Rocky Mountain spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever (RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever) is a bacterial infection caused by the obligate intracellular parasite Rickettsia rickettsiiRickettsia rickettsiiA species of gram-negative, aerobic bacteria that is the etiologic agent of rocky mountain spotted fever. Its cells are slightly smaller and more uniform in size than those of rickettsia prowazekii.Rickettsia. Transmission occurs through an arthropod vector, most commonly the American dog tickAmerican Dog TickRocky Mountain Spotted Fever (Dermacentor variabilisDermacentor VariabilisRocky Mountain Spotted Fever). Rocky Mountain spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever is prevalent in the southeastern United States. Early signs and symptoms of RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever are nonspecific and include a high feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, severe headacheHeadacheThe symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders.Brain Abscess, and rashRashRocky Mountain Spotted Fever. The rashRashRocky Mountain Spotted Fever is characteristic in that it begins peripherally and moves centrally, and also appears on the hands and soles. A high clinical suspicion is required for diagnosis, and empiric treatment with doxycycline is recommended within 5 days of symptom onset.
Rocky Mountain spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever (RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever) is an infectious disease caused by the bacteriaBacteriaBacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. BacteriologyRickettsia rickettsiiRickettsia rickettsiiA species of gram-negative, aerobic bacteria that is the etiologic agent of rocky mountain spotted fever. Its cells are slightly smaller and more uniform in size than those of rickettsia prowazekii.Rickettsia, which is usually transmitted by ticksTicksBlood-sucking acarid parasites of the order ixodida comprising two families: the softbacked ticks (argasidae) and hardbacked ticks (ixodidae). Ticks are larger than their relatives, the mites. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many tick-borne diseases, including the transmission of rocky mountain spotted fever; tularemia; babesiosis; african swine fever; and relapsing fever.Coxiella/Q Fever.
Epidemiology[6,9,10]
IncidenceIncidenceThe number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time.Measures of Disease Frequency: has risen from 495 cases in 2000 to about 5,200 cases in 2019
Affects all ages, but most common in those 40–64 years of age
Most common rickettsial infection in the United States
Occurs throughout the United States, but most prevalent in the southeastern and south-central states:
Arkansas, Missouri, North Carolina, Tennessee, and Virginia account for > 50% of cases.
More cases have been reported in Arizona in the past several years.
Outside the United States:
Canada
Mexico
South America (Brazil, Bolivia, Argentina, and Colombia)
Distribution is dependent on the location of the tick vector.
Risk factors:
Season:
More common in spring and summer
> 90% of cases are from April to September when adult DermacentorDermacentorA widely distributed genus of ticks, in the family ixodidae, including a number that infest humans and other mammals. Several are vectors of diseases such as tularemia; rocky mountain spotted fever; colorado tick fever; and anaplasmosis.RickettsiaticksTicksBlood-sucking acarid parasites of the order ixodida comprising two families: the softbacked ticks (argasidae) and hardbacked ticks (ixodidae). Ticks are larger than their relatives, the mites. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many tick-borne diseases, including the transmission of rocky mountain spotted fever; tularemia; babesiosis; african swine fever; and relapsing fever.Coxiella/Q Fever are most active.
Increased tick burden: residency near wooded areas or areas with high grass
Distribution of spotted fever rickettsiosis in the United States, of which RMSF is a type, 2014
Image: “US distribution of spotted fever rickettsiosis” by CDC. License: Public Domain
Brown dog tick (Rhipicephalus sanguineusRhipicephalus sanguineusA species of tick (ticks) in the family ixodidae, distributed throughout the world but abundant in southern europe. It will feed on a wide variety of mammals, but dogs are its preferred host. It transmits a large number of diseases including babesiosis; theileriosis; ehrlichiosis; and mediterranean spotted fever.Rocky Mountain Spotted Fever): Arizona
Central and South America:
Brown dog tick (Rhipicephalus sanguineusRhipicephalus sanguineusA species of tick (ticks) in the family ixodidae, distributed throughout the world but abundant in southern europe. It will feed on a wide variety of mammals, but dogs are its preferred host. It transmits a large number of diseases including babesiosis; theileriosis; ehrlichiosis; and mediterranean spotted fever.Rocky Mountain Spotted Fever): Mexico
Yellow dog tick (AmblyommaAmblyommaA genus of hardbacked ticks, in the family Ixodidae. It includes the lone star tick, Amblyomma americanum, and the Gulf Coast tick, Amblyomma maculatum, in the Americas. Amblyomma americanum is the primary vector of Ehrlichia chaffeensis and Ehrlichia ewingii which cause Ehrlichiosis. Other Amblyomma-associated diseases include tularemia and rickettsiosis.Rickettsia aureolatum): Brazil
Adult Dermacentor tick
Image: “Adult Dermacentor spp. tick” by Center for Infectious Diseases and Travel Medicine, University Hospital Freiburg, Hugstetter Strasse, Germany. License: CC BY 2.0
Pathophysiology
R. rickettsii are transmitted to human hosts through the bite of an infected tick.[4,5]
During feeding, bacteriaBacteriaBacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology are released from tick salivary glandsSalivary glandsThe salivary glands are exocrine glands positioned in and around the oral cavity. These glands are responsible for secreting saliva into the mouth, which aids in digestion. There are 3 major paired salivary glands: the sublingual, submandibular, and parotid glands.Salivary Glands: Anatomy.
RickettsiaRickettsiaRickettsiae are a diverse collection of obligate intracellular, gram-negative bacteria that have a tropism for vascular endothelial cells. The vectors for transmission vary by species but include ticks, fleas, mites, and lice. Rickettsiahave a tropism for endothelial cells and adhere to the cells via membrane lipopolysaccharidesLipopolysaccharidesLipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: lipid a, core polysaccharide, and o-specific chains (o antigens). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal b-cell mitogens commonly used in laboratory immunology.Diarrheagenic E. coli (LPS) and rickettsial outer membrane proteinsRickettsial Outer Membrane ProteinsRocky Mountain Spotted Fever (rOmpsRompsRocky Mountain Spotted Fever).
RickettsiaRickettsiaRickettsiae are a diverse collection of obligate intracellular, gram-negative bacteria that have a tropism for vascular endothelial cells. The vectors for transmission vary by species but include ticks, fleas, mites, and lice. Rickettsiaare then endocytosed into host cells and cause host cell lysis via:
Phospholipase DPhospholipase DAn enzyme found mostly in plant tissue. It hydrolyzes glycerophosphatides with the formation of a phosphatidic acid and a nitrogenous base such as choline. This enzyme also catalyzes transphosphatidylation reactions.Yersinia pestis/Plague
tlyC
RickettsiaRickettsiaRickettsiae are a diverse collection of obligate intracellular, gram-negative bacteria that have a tropism for vascular endothelial cells. The vectors for transmission vary by species but include ticks, fleas, mites, and lice. Rickettsiaare then able to spread hematogenously through the blood and also via lymphatics:
Damage to small vessels are due to cell injuryCell injuryThe cell undergoes a variety of changes in response to injury, which may or may not lead to cell death. Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible. Cell Injury and Death caused by phospholipases, proteasesProteasesProteins and Peptides and free radical-induced lipid peroxidationLipid peroxidationPeroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.Drug-Induced Liver Injury.
Continued replication within vessels causes immune responses with increased lymphocytesLymphocytesLymphocytes are heterogeneous WBCs involved in immune response. Lymphocytes develop from the bone marrow, starting from hematopoietic stem cells (HSCs) and progressing to common lymphoid progenitors (CLPs). B and T lymphocytes and natural killer (NK) cells arise from the lineage.Lymphocytes: Histology and macrophagesMacrophagesThe relatively long-lived phagocytic cell of mammalian tissues that are derived from blood monocytes. Main types are peritoneal macrophages; alveolar macrophages; histiocytes; kupffer cells of the liver; and osteoclasts. They may further differentiate within chronic inflammatory lesions to epithelioid cells or may fuse to form foreign body giant cells or langhans giant cells.Innate Immunity: Phagocytes and Antigen Presentation → vasculitisVasculitisInflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body.Systemic Lupus Erythematosus.
Widespread vasculitisVasculitisInflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body.Systemic Lupus Erythematosus can result in microhemorrhages and disseminated intravascular coagulationDisseminated intravascular coagulationDisseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation (DICDICDisseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation).
VasculitisVasculitisInflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body.Systemic Lupus Erythematosus → ↑ vascular permeability, which can lead to:
EdemaEdemaEdema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema (peripheral, cerebral, and pulmonary)
HypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension and shockShockShock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock → ↓ organ perfusion and dysfunction
Symptoms usually occur within 2–14 days of exposure to an infected tick bite. Initial symptoms may be vague and non-specific (feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, generalized malaiseMalaiseTick-borne Encephalitis Virus). PatientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship may not be aware of tick exposure.
Classic triad[5,6]
All 3 components of the “classic triad” are seen in only 44% of cases.[7]
FeverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever (> 38.9°C (102.0°F))
HeadacheHeadacheThe symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders.Brain Abscess(less common in children)[13]
Appears 3–5 days after onset of symptoms in about 90% of patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship; < 50% have a rashRashRocky Mountain Spotted Fever within the 1st 72 hours
Later: can become petechial (considered a sign of severe disease)
Distribution:
Usually starts on the wrists and ankles, then generalizes
Involves the palms and soles (but not always)[11]
Nonpruritic
Note: About 10% of patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship will not develop a rashRashRocky Mountain Spotted Fever (“spotless” RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever).
Classical RMSF rash, maculopapular and not sparing the soles and palms
NauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics and/or vomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
EdemaEdemaEdema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema (around eyes and extremities)
Neurologic:
Confusion
LethargyLethargyA general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction.Hyponatremia
Stupor
Ocular involvement:[8]
ConjunctivitisConjunctivitisConjunctivitis is a common inflammation of the bulbar and/or palpebral conjunctiva. It can be classified into infectious (mostly viral) and noninfectious conjunctivitis, which includes allergic causes. Patients commonly present with red eyes, increased tearing, burning, foreign body sensation, and photophobia. Conjunctivitis
Retinal hemorrhages
PapilledemaPapilledemaSwelling of the optic disk, usually in association with increased intracranial pressure, characterized by hyperemia, blurring of the disk margins, microhemorrhages, blind spot enlargement, and engorgement of retinal veins. Chronic papilledema may cause optic atrophy and visual loss.Idiopathic Intracranial Hypertension
Complications[2,5,6]
Complications of untreated infection may include:
EncephalitisEncephalitisEncephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis.Encephalitis
MyocarditisMyocarditisMyocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis/arrhythmia
Pulmonary edemaPulmonary edemaPulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure.Pulmonary Edema
Adult respiratory distress syndrome
Arrhythmias
Coagulopathy (including DICDICDisseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation; rare)
Gastrointestinal bleedingGastrointestinal bleedingGastrointestinal bleeding (GIB) is a symptom of multiple diseases within the gastrointestinal (GI) tract. Gastrointestinal bleeding is designated as upper or lower based on the etiology’s location to the ligament of Treitz. Depending on the location of the bleeding, the patient may present with hematemesis (vomiting blood), melena (black, tarry stool), or hematochezia (fresh blood in stools). Gastrointestinal Bleeding
The diagnostic workup for RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever may depend on practice location. The following information is based on US and European guidelines. See your local guidelines for additional guidance.
History[6,7]
Recent travel to areas with high prevalencePrevalenceThe total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time.Measures of Disease Frequency
Local lymphadenopathyLymphadenopathyLymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy
Conjunctival erythemaErythemaRedness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes.Chalazion
SeizuresSeizuresA seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
GangreneGangreneDeath and putrefaction of tissue usually due to a loss of blood supply.Small Bowel Obstruction of digits and ears
General laboratory studies[2,6,12,13]
Most patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship will have normal laboratory findings initially, including normal WBC count (but often immature myeloid cellsMyeloid CellsThe classes of bone marrow-derived blood cells in the monocytic series (monocytes and their precursors) and granulocytic series (granulocytes and their precursors).White Myeloid Cells: Histology).
Later abnormalities include:
ThrombocytopeniaThrombocytopeniaThrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia (30%–50% of cases)
AnemiaAnemiaAnemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types (30%)
Decreased fibrinogenFibrinogenPlasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides a and b, the proteolytic action of other enzymes yields different fibrinogen degradation products.Hemostasis concentration and increased fibrinFibrinA protein derived from fibrinogen in the presence of thrombin, which forms part of the blood clot.Rapidly Progressive Glomerulonephritis split products
Leukopenia
Prolonged partial thromboplastin timePartial thromboplastin timeThe time required for the appearance of fibrin strands following the mixing of plasma with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of blood coagulation.Hemostasis (PTT) and prothrombin timeProthrombin timeClotting time of plasma recalcified in the presence of excess tissue thromboplastin. Factors measured are fibrinogen; prothrombin; factor V; factor VII; and factor X.Hemostasis (PT) due to consumption of clotting factors
Increased serum liverLiverThe liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy and muscle enzymesEnzymesEnzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes (ASTASTEnzymes of the transferase class that catalyze the conversion of l-aspartate and 2-ketoglutarate to oxaloacetate and l-glutamate.Liver Function Tests, ALTALTAn enzyme that catalyzes the conversion of l-alanine and 2-oxoglutarate to pyruvate and l-glutamate.Liver Function Tests, LDHLDHOsteosarcoma, CK)
HyperbilirubinemiaHyperbilirubinemiaA condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine.Jaundice
AzotemiaAzotemiaA biochemical abnormality referring to an elevation of blood urea nitrogen and creatinine. Azotemia can be produced by kidney diseases or other extrarenal disorders. When azotemia becomes associated with a constellation of clinical signs, it is termed uremia.Acute Kidney Injury
HyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia
Confirmatory tests[6,11‒13]
SerologySerologyThe study of serum, especially of antigen-antibody reactions in vitro.Yellow Fever Virus:
Indirect immunofluorescence assay (IFA): most widely available and utilized
Perform both acute and convalescent serologySerologyThe study of serum, especially of antigen-antibody reactions in vitro.Yellow Fever Virus testing to compare levels:[6]
1st sample: within 1st 2 weeks
2nd sample: 2‒4 weeks later
SeroconversionSeroconversionThe appearance of antibodies against causative agents in the blood of individuals during the course of an infection or following immunization.HIV Infection and AIDS: 4x increase in IgGIgGThe major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b.Hypersensitivity Pneumonitis antibody levels
Immunoglobulin M (IgMIgMA class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.Immunoglobulins: Types and Functions) and IgGIgGThe major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b.Hypersensitivity PneumonitisantibodiesAntibodiesImmunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution.Immunoglobulins: Types and Functions generally appear 7–10 days after illness onset.[13]
Note: Acute serologySerologyThe study of serum, especially of antigen-antibody reactions in vitro.Yellow Fever Virus is often negative and not helpful in the first 5 days. Treatment should be based on clinical manifestations and not delayed.
Polymerase chain reactionPolymerase chain reactionPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR) (PCRPCRPolymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules.Polymerase Chain Reaction (PCR)) on a blood sample:
Low sensitivity (as circulating organisms are low)
Direct immunofluorescence testing or immunoperoxidase staining
Not readily available across the United States
70% sensitive, 100% specific
Sensitivity decreases when antibiotic treatment has been given.
Culture:
Difficult to perform
Reserved for researchResearchCritical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws.Conflict of Interest purposes
Giemsa-stained R. rickettsii in the cells of a tick
Management of RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever may vary depending on practice location. The following information is based on US-based guidelines. Please see your local guidelines for more guidance.
Antibiotics[6,13]
Should be started empirically if there is high clinical suspicion
Preferably within 5 days of symptom onset
1st line: doxycycline (oral or intravenous)
Treatment of choice, even in pregnancyPregnancyThe status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth.Pregnancy: Diagnosis, Physiology, and Care
Dosing:
Adults: 100 mg every 12 hours for 5–14 days; give a loading doseLoading DoseDosage Calculation of 200 mg x 1 if critically ill
Treat for ≥ 3 days after the feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever subsides and clinical improvement
Minimum: 5–7 days
Severe disease may require a longer treatment period.
If doxycycline cannot be used (e.g., severe allergyAllergyAn abnormal adaptive immune response that may or may not involve antigen-specific IgEType I Hypersensitivity Reaction) or if the patient is pregnant → consult infectious disease specialist
Alternative: chloramphenicolChloramphenicolChloramphenicol, the only clinically relevant drug in the amphenicol class, is a potent inhibitor of bacterial protein synthesis by binding to the 50S ribosomal subunit and preventing peptide bond formation. Chloramphenicol is a broad-spectrum antibiotic with wide distribution; however, due to its toxicity, its use is limited to severe infections.Chloramphenicol (less effective)
May be difficult to acquire
Potential risks:
Aplastic anemiaAplastic AnemiaAplastic anemia (AA) is a rare, life-threatening condition characterized by pancytopenia and hypocellularity of the bone marrow (in the absence of any abnormal cells) reflecting damage to hematopoietic stem cells. Aplastic anemia can be acquired or inherited, however, most cases of AA are acquired and caused by autoimmune damage to hematopoietic stem cells. Aplastic Anemia
Note: Use of any antibiotics besides doxycycline (including chloramphenicolChloramphenicolChloramphenicol, the only clinically relevant drug in the amphenicol class, is a potent inhibitor of bacterial protein synthesis by binding to the 50S ribosomal subunit and preventing peptide bond formation. Chloramphenicol is a broad-spectrum antibiotic with wide distribution; however, due to its toxicity, its use is limited to severe infections.Chloramphenicol) may increase the risk of death.
Additional care considerations[14]
Deciding care setting:
Individuals at higher risk for hospitalizationHospitalizationThe confinement of a patient in a hospital.Delirium:
ImmunocompromisedimmunocompromisedA human or animal whose immunologic mechanism is deficient because of an immunodeficiency disorder or other disease or as the result of the administration of immunosuppressive drugs or radiation.Gastroenteritis individuals, such as those:
Indications for hospitalizationHospitalizationThe confinement of a patient in a hospital.Delirium (those with severe, or the potential for severe, disease):
HypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension and shockShockShock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock
Inability to tolerate oral doxycycline
Social factors that may prohibit outpatient therapy and follow-up
ComorbiditiesComorbiditiesThe presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.St. Louis Encephalitis Virus (e.g., immunocompromisedimmunocompromisedA human or animal whose immunologic mechanism is deficient because of an immunodeficiency disorder or other disease or as the result of the administration of immunosuppressive drugs or radiation.Gastroenteritis state, G6PDG6PDPentose Phosphate Pathway deficiency)
Outpatient care:
Appropriate for those who:
Have mild, early disease
Can tolerate oral doxycycline
Requires close follow-up care → keep in contact with patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship to ensure response to therapy
FeverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever generally subsides within 24‒48 hours.
May need to consider an alternative diagnosis or coinfection if feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever persists
In cases where the diagnosis is uncertain, a 24-hour “watch-and-wait” approach to antibiotic initiation may be considered:
Ideal candidates:
Appear well (may have feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
No obvious tick bite
Normal physical examination
Laboratory values within normal range
Requires close monitoring owing to the potential for rapid clinical decline
Hospital care:
Specialist consultations (if available):
Critical care
Infectious disease
Monitor for:
Treatment response: clinical improvement may take > 48 hours in severe disease
Intracranial hypertensionHypertensionHypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
ShockShockShock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock
ARDS
Renal failureRenal failureConditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate.Crush Syndrome
HyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia
In addition to antibiotics (e.g., IV doxycycline), therapies may include (depending on the clinical course):
DialysisDialysisRenal replacement therapy refers to dialysis and/or kidney transplantation. Dialysis is a procedure by which toxins and excess water are removed from the circulation. Hemodialysis and peritoneal dialysis (PD) are the two types of dialysis, and their primary difference is the location of the filtration process (external to the body in hemodialysis versus inside the body for PD).Peritoneal Dialysis and Hemodialysis
Blood and/or platelet transfusions
AnticonvulsantAnticonvulsantAnticonvulsant drugs are pharmacological agents used to achieve seizure control and/or prevent seizure episodes. Anticonvulsants encompass various drugs with different mechanisms of action including ion-channel (Na+ and Ca+2) blocking and GABA reuptake inhibition. First-Generation Anticonvulsant Drugs medications
Reporting[14]
In the US, RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever is a reportable disease under a new category (since 2010) called spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever rickettsiosis (SFR). Notify the local health department of potential cases.
Prevention
Prevention of tick bites
Detection and removal of attached ticksTicksBlood-sucking acarid parasites of the order ixodida comprising two families: the softbacked ticks (argasidae) and hardbacked ticks (ixodidae). Ticks are larger than their relatives, the mites. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many tick-borne diseases, including the transmission of rocky mountain spotted fever; tularemia; babesiosis; african swine fever; and relapsing fever.Coxiella/Q Fever
PrognosisPrognosisA prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations.Non-Hodgkin Lymphomas
Chronic alcohol use disorderAlcohol use disorderAlcohol is one of the most commonly used addictive substances in the world. Alcohol use disorder (AUD) is defined as pathologic consumption of alcohol leading to impaired daily functioning. Acute alcohol intoxication presents with impairment in speech and motor functions and can be managed in most cases with supportive care. Alcohol Use Disorder
MeningococcalmeningitisMeningitisMeningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis: a meningeal infection with Neisseria meningitidisNeisseria meningitidisA species of gram-negative, aerobic bacteria. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the nasopharynx. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis. It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being a, b, c, y, and w-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.Neisseria.FeverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, headacheHeadacheThe symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders.Brain Abscess, and rashRashRocky Mountain Spotted Fever are commonly noted in patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship with meningococcal meningitisMeningitisMeningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis. However, there is usually no history of tick exposure and symptoms do not improve with doxycycline. Diagnosis is established with lumbar punctureLumbar PunctureFebrile Infant. Treatment is usually with ceftriaxoneCeftriaxoneA broad-spectrum cephalosporin antibiotic and cefotaxime derivative with a very long half-life and high penetrability to meninges, eyes and inner ears.Cephalosporins or penicillinPenicillinRheumatic Fever.
Infectious mononucleosisMononucleosisInfectious mononucleosis (IM), also known as “the kissing disease,” is a highly contagious viral infection caused by the Epstein-Barr virus. Its common name is derived from its main method of transmission: the spread of infected saliva via kissing. Clinical manifestations of IM include fever, tonsillar pharyngitis, and lymphadenopathy. Mononucleosis: a viral infection caused by the Epstein-Barr virusEpstein-Barr VirusEpstein-Barr virus (EBV) is a linear, double-stranded DNA virus belonging to the Herpesviridae family. This highly prevalent virus is mostly transmitted through contact with oropharyngeal secretions from an infected individual. The virus can infect epithelial cells and B lymphocytes, where it can undergo lytic replication or latency. Epstein-Barr Virus. Initial clinical symptoms of RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever and infectious mononucleosisMononucleosisInfectious mononucleosis (IM), also known as “the kissing disease,” is a highly contagious viral infection caused by the Epstein-Barr virus. Its common name is derived from its main method of transmission: the spread of infected saliva via kissing. Clinical manifestations of IM include fever, tonsillar pharyngitis, and lymphadenopathy. Mononucleosis are very similar to any viral infection, with malaiseMalaiseTick-borne Encephalitis Virus and low-grade feverLow-Grade FeverErythema Infectiosum. MononucleosisMononucleosisInfectious mononucleosis (IM), also known as “the kissing disease,” is a highly contagious viral infection caused by the Epstein-Barr virus. Its common name is derived from its main method of transmission: the spread of infected saliva via kissing. Clinical manifestations of IM include fever, tonsillar pharyngitis, and lymphadenopathy. Mononucleosis can present with a rashRashRocky Mountain Spotted Fever but usually spares the palms and soles. Diagnosed with a monospot test. Treatment is largely supportive.
Thrombotic thrombocytopenic purpuraThrombotic thrombocytopenic purpuraThrombotic thrombocytopenic purpura (TTP) is a life-threatening condition due to either a congenital or an acquired deficiency of ADAMTS-13, a metalloproteinase that cleaves multimers of von Willebrand factor (VWF). The large multimers then aggregate excessive platelets resulting in microvascular thrombosis and an increase in consumption of platelets. Thrombotic Thrombocytopenic Purpura (TTPTTPThrombotic thrombocytopenic purpura (TTP) is a life-threatening condition due to either a congenital or an acquired deficiency of adamts-13, a metalloproteinase that cleaves multimers of von Willebrand factor (vWF). The large multimers then aggregate excessive platelets resulting in microvascular thrombosis and an increase in consumption of platelets.Thrombotic Thrombocytopenic Purpura): a life-threatening condition caused by defects of von Willebrand factorvon Willebrand factorA high-molecular-weight plasma protein, produced by endothelial cells and megakaryocytes, that is part of the factor VIII/von Willebrand factor complex. The von Willebrand factor has receptors for collagen, platelets, and ristocetin activity as well as the immunologically distinct antigenic determinants. It functions in adhesion of platelets to collagen and hemostatic plug formation. The prolonged bleeding time in von Willebrand diseases is due to the deficiency of this factor.Hemostasis. Complications of RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever include thrombocytopeniaThrombocytopeniaThrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia and disseminated intravascular coagulationDisseminated intravascular coagulationDisseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation (DICDICDisseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation), which can cause a purpuric rashRashRocky Mountain Spotted Fever and be mistaken for TTPTTPThrombotic thrombocytopenic purpura (TTP) is a life-threatening condition due to either a congenital or an acquired deficiency of adamts-13, a metalloproteinase that cleaves multimers of von Willebrand factor (vWF). The large multimers then aggregate excessive platelets resulting in microvascular thrombosis and an increase in consumption of platelets.Thrombotic Thrombocytopenic Purpura. Diagnosis is established with blood work. Treatment involves plasmapheresisPlasmapheresisProcedure whereby plasma is separated and extracted from anticoagulated whole blood and the red cells retransfused to the donor. Plasmapheresis is also employed for therapeutic use.Stevens-Johnson Syndrome and steroidsSteroidsA group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus.Benign Liver Tumors.
MeaslesMeaslesMeasles (also known as rubeola) is caused by a single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae. It is highly contagious and spreads by respiratory droplets or direct-contact transmission from an infected person. Typically a disease of childhood, measles classically starts with cough, coryza, and conjunctivitis, followed by a maculopapular rash. Measles Virus: a viral infectionassociated with feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever and maculopapularMaculopapularDermatologic ExaminationrashRashRocky Mountain Spotted Fever. The rashRashRocky Mountain Spotted Fever usually starts on the face and then progresses to the trunk and extremities, sparing the palms and soles. Diagnosis is made clinically and confirmed by serologySerologyThe study of serum, especially of antigen-antibody reactions in vitro.Yellow Fever Virus, and treatment is largely supportive.
Billing and Coding
Diagnosis Codes:
These codes are used to formally document a diagnosis of Rocky Mountain Spotted FeverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever (RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever), a critical step for patient records, billing, and mandatory reporting to public health agencies like the CDC.
Domain
Code
Description
ICD-10-CM
A77.0
Spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever due to Rickettsia rickettsiiRickettsia rickettsiiA species of gram-negative, aerobic bacteria that is the etiologic agent of rocky mountain spotted fever. Its cells are slightly smaller and more uniform in size than those of rickettsia prowazekii.Rickettsia
ICD-11
1C31.0
Spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever due to Rickettsia rickettsiiRickettsia rickettsiiA species of gram-negative, aerobic bacteria that is the etiologic agent of rocky mountain spotted fever. Its cells are slightly smaller and more uniform in size than those of rickettsia prowazekii.Rickettsia
SNOMED CT
27954003
Rocky Mountain spotted feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever (disorder)
Evaluation & Workup:
These laboratory codes are used to order serologySerologyThe study of serum, especially of antigen-antibody reactions in vitro.Yellow Fever Virus and other blood tests to confirm the presence of Rickettsia rickettsiiRickettsia rickettsiiA species of gram-negative, aerobic bacteria that is the etiologic agent of rocky mountain spotted fever. Its cells are slightly smaller and more uniform in size than those of rickettsia prowazekii.RickettsiaantibodiesAntibodiesImmunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution.Immunoglobulins: Types and Functions. Because of the disease’s severity, treatment is often started before these confirmatory results are available.
Domain
Code
Description
CPT
86757
Antibody; RickettsiaRickettsiaRickettsiae are a diverse collection of obligate intracellular, gram-negative bacteria that have a tropism for vascular endothelial cells. The vectors for transmission vary by species but include ticks, fleas, mites, and lice. Rickettsia
Complete (CBC), automated (Hgb, Hct, RBC, WBC and platelet count)
LOINC
6516-2
Rickettsia rickettsiiRickettsia rickettsiiA species of gram-negative, aerobic bacteria that is the etiologic agent of rocky mountain spotted fever. Its cells are slightly smaller and more uniform in size than those of rickettsia prowazekii.Rickettsia Ab [Titer] in Serum
Medications:
These codes are used in pharmacy and hospital systems to prescribe and track the administration of doxycycline, the essential, life-saving antibiotic treatment for RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever in both adults and children.
Domain
Code
Description
RxNorm
3640
Doxycycline (ingredient)
ATC
J01AA02
Doxycycline
HCPCS
J0120
Injection, TetracyclineTetracyclineA naphthacene antibiotic that inhibits amino Acyl tRNA binding during protein synthesis.Drug-Induced Liver Injury, up to 250 mg
Complications & Supportive Procedures:
These codes are used in critical care settings to document and manage severe, life-threatening complications of untreated RMSFRMSFRocky mountain spotted fever (RMSF) is a bacterial infection caused by the obligate intracellular parasite rickettsia rickettsii. Transmission occurs through an arthropod vector, most commonly the american dog tick (dermacentor variabilis). Early signs and symptoms of rmsf are nonspecific and include a high fever, severe headache, and rash.Rocky Mountain Spotted Fever, such as encephalitisEncephalitisEncephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis.Encephalitis, acute kidney failure, or the need for mechanical ventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing.
Domain
Code
Description
ICD-10-CM
G04.90
EncephalitisEncephalitisEncephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis.Encephalitis and encephalomyelitis, unspecified
ICD-10-CM
N17.9
Acute kidney failure, unspecified
ICD-10-CM
J80
Acute respiratory distress syndromeAcute Respiratory Distress SyndromeAcute respiratory distress syndrome is characterized by the sudden onset of hypoxemia and bilateral pulmonary edema without cardiac failure. Sepsis is the most common cause of ARDS. The underlying mechanism and histologic correlate is diffuse alveolar damage (DAD). Acute Respiratory Distress Syndrome (ARDS)
ICD-10-PCS
5A1955Z
Respiratory VentilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing, Greater than 96 Consecutive Hours
References
Riedel, S., Jawetz, E., Melnick, J. L., Adelberg, E. A. (2022). Jawetz, Melnick & Adelberg’s Medical Microbiology (pp. 357–361). New York: McGraw-Hill Education.
Fournier, P.-E., Raoult, D. (2019). Rickettsial infections. In Crow, M. K., et al. (Eds.), Goldman-Cecil Medicine. (26th ed., vol. 2, pp. 2017–2026).
Sathiamoorthi, S., Smith, W. M. (2016). The eye and tick-borne disease in the United States. Current Opinion in Ophthalmology, 27(6), 530–537. https://doi.org/10.1097/ICU.0000000000000308
Kjemtrup, A. M., Padgett, K., et al. (2022). A forty-year review of Rocky Mountain spotted fever cases in California shows clinical and epidemiologic changes. PLoS Neglected Tropical Diseases, 16(9), e0010738. https://doi.org/10.1371/journal.pntd.0010738
Bishop, A., Borski, J., Wang, H.-H., et al. (2022). Increasing incidence of spotted fever group rickettsioses in the United States, 2010–2018. Vector Borne and Zoonotic Diseases, 22(9), 491–497. https://doi.org/10.1089/vbz.2022.0021
Jay, R., & Armstrong, P. A. (2020). Clinical characteristics of Rocky Mountain spotted fever in the United States: A literature review. Journal of Vector Borne Diseases, 57(2), 114–120. https://doi.org/10.4103/0972-9062.310863
Committee on Infectious Diseases, American Academy of Pediatrics. Rocky Mountain spotted fever. In Kimberlin, D. W., et al. (Eds). Red Book: 2018 Report of the Committee on Infectious Diseases (31st ed.).
Centers for Disease Control and Prevention (2016). Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis—United States. MMWR. Retrieved January 22, 2023, from https://www.cdc.gov/mmwr/volumes/65/rr/pdfs/rr6502.pdf
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