Septic arthritis (Clinical)

Epidemiology and Etiology

Epidemiology^[1,9]

• Incidence Incidence The 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: 2–6 cases per 100,000 people in the United States
• More common in children than adults: peaks between the ages of 2 and 3 years
• 2:1 male predominance

Etiology^[1,7]

The majority of septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease are monomicrobial. Common organisms include:

• Staphylococci:
  • Staphylococcus aureus Staphylococcus aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Brain Abscess (most common)
  • S. epidermidis S. epidermidis A species of staphylococcus that is a spherical, non-motile, gram-positive, chemoorganotrophic, facultative anaerobe. Mainly found on the skin and mucous membrane of warm-blooded animals, it can be primary pathogen or secondary invader. Staphylococcus
• Streptococci:
  • Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus pyogenes
  • S. pneumoniae
  • S. agalactiae
• Gram-negative bacteria gram-negative bacteria Bacteria which lose crystal violet stain but are stained pink when treated by gram’s method. Bacteriology:
  • Pseudomonas aeruginosa Pseudomonas aeruginosa A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. Aeruginosa is a major agent of nosocomial infection. Pseudomonas
  • Escherichia coli Escherichia coli The gram-negative bacterium Escherichia coli is a key component of the human gut microbiota. Most strains of E. coli are avirulent, but occasionally they escape the GI tract, infecting the urinary tract and other sites. Less common strains of E. coli are able to cause disease within the GI tract, most commonly presenting as abdominal pain and diarrhea. Escherichia coli
  • Kingella kingae
  • Neisseria gonorrhoeae Neisseria gonorrhoeae A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of gonorrhea. Neisseria: Consider in sexually active young adults, often with simultaneous genital infection with Chlamydia trachomatis Chlamydia trachomatis Type species of Chlamydia causing a variety of ocular and urogenital diseases. Chlamydia.
  • Haemophilus influenzae Haemophilus Influenzae A species of Haemophilus found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through viii. Haemophilus
  • Salmonella Salmonella Salmonellae are gram-negative bacilli of the family Enterobacteriaceae. Salmonellae are flagellated, non-lactose-fermenting, and hydrogen sulfide-producing microbes. Salmonella enterica, the most common disease-causing species in humans, is further classified based on serotype as typhoidal (S. typhi and paratyphi) and nontyphoidal (S. enteritidis and typhimurium). Salmonella species

Risk factors^[1,3,5,7,11]

• Infants and children:
  • Prematurity Prematurity Neonatal Respiratory Distress Syndrome
  • Hemophilia Hemophilia The hemophilias are a group of inherited, or sometimes acquired, disorders of secondary hemostasis due to deficiency of specific clotting factors. Hemophilia A is a deficiency of factor VIII, hemophilia B a deficiency of factor IX, and hemophilia C a deficiency of factor XI. Patients present with bleeding events that may be spontaneous or associated with minor or major trauma. Hemophilia (due to hemarthroses)
  • Immunosuppression:
    • Chemotherapy Chemotherapy Osteosarcoma
    • HIV HIV Anti-HIV Drugs
    • Sickle cell anemia Sickle cell anemia A disease characterized by chronic hemolytic anemia, episodic painful crises, and pathologic involvement of many organs. It is the clinical expression of homozygosity for hemoglobin S. Sickle Cell Disease
    • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
• Adults:
  • Age > 80 years
  • Chronic disease/immunosuppression:
    • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • HIV HIV Anti-HIV Drugs
  • Joint disease:
    • Rheumatoid arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis
    • Osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis
    • Gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout
  • Joint procedures:
    • Surgery
    • Intra-articular injections
    • Joint prosthesis Joint prosthesis Prostheses used to partially or totally replace a human or animal joint. Soft Tissue Abscess
  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease or ulcers
  • IV drug use

Prosthetic joint infection (PJI)^[7,14]

• Usually occurs within 2 years after surgery
• Unlike native joints, prosthetic joints Prosthetic joints Prostheses used to partially or totally replace a human or animal joint. Soft Tissue Abscess do not contain cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology and, therefore, are not at risk for cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology destruction. 
• Chronic infection (> 3 months after surgery) is more common than acute infection (1–3 months after surgery).
• Risk factors:
  • Longer procedural time
  • Postoperative wound drainage
  • Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
  • Malnutrition Malnutrition Malnutrition is a clinical state caused by an imbalance or deficiency of calories and/or micronutrients and macronutrients. The 2 main manifestations of acute severe malnutrition are marasmus (total caloric insufficiency) and kwashiorkor (protein malnutrition with characteristic edema). Malnutrition in children in resource-limited countries
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
  • Tobacco use and heavy alcohol use
  • Prior surgery at the same site
  • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs
  • Bacterial colonization Colonization Bacteriology
• Microbiology: S. aureus S. aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Staphylococcus is the most common organism.

Pathophysiology

Joints can be inoculated in different ways. Infecting organisms multiply in the synovial fluid and synovial lining.^[1,5] 

• Invasion of the joint occurs through:
  • Hematogenous seeding Hematogenous Seeding Septic Arthritis (most common)
  • Direct inoculation of organisms into the joint
  • Extension Extension Examination of the Upper Limbs from an adjacent infection
• Previously damaged joints are particularly susceptible to infection by way of:
  • Neovascularization
  • Dysfunctional cellular defenses
  • Absent basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN) on the synovial membrane Synovial Membrane The inner membrane of a joint capsule surrounding a freely movable joint. It is loosely attached to the external fibrous capsule and secretes synovial fluid. Hip Joint: Anatomy
• Progression of the disease:
  • Bacterial invasion → inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation → release of cytokines Cytokines Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. Adaptive Immune Response and proteases Proteases Proteins and Peptides
  • This response, plus bacterial toxins → destruction of:
    • Articular cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology
    • Synovium
    • Subchondral bone Subchondral Bone Osteochondritis Dissecans
  • Pannus Pannus A genus of cyanobacteria in the family synechococcaceae that is free-floating and occurs in various water environments attaching to algae and submersed plants. Septic Arthritis formation occurs.
  • If a large effusion develops → impairment of the blood supply → aseptic necrosis Aseptic Necrosis Septic Arthritis

Clinical Presentation and Diagnosis

Clinical presentation^[1–5]

• Usually acute in onset
• Joint signs and symptoms:
  • Swelling Swelling Inflammation and effusion
  • Warmth
  • Moderate-to-severe pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion
  • Restricted movement
  • Usually monoarticular, but 20% of cases may be oligo- or polyarticular
• Constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis:
  • Fever Fever Fever 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
  • Fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia
  • Tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children
• Commonly affected joints:
  • Knee (> 50% of cases)
  • Wrist
  • Ankle
  • Hip
  • Elbow
  • Axial Axial Computed Tomography (CT) joints (in IV drug users):
    • Sacroiliac
    • Sternoclavicular joint Sternoclavicular Joint Examination of the Upper Limbs
• Strongly consider septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis in acute onset of a hot, swollen, and tender joint with restricted movement.^[6]
• PJI:
  • Acute infection presents similarly to an infection of a native joint.
    • New joint effusion Joint Effusion Septic Arthritis
    • Erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion
    • Warmth 
    • Constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis ( fever Fever Fever 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, malaise Malaise Tick-borne Encephalitis Virus)
  • Chronic infection:
    • Has a more subtle pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways (but suspect in cases of new pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways after a pain-free interval post surgery)
    • Can be associated with an open wound, abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease, or sinus tract

Arthrocentesis Arthrocentesis Puncture and aspiration of fluid (e.g., synovial fluid) from a joint cavity. It is used sometimes to irrigate or administer drugs into a joint cavity. Septic Arthritis^[6–9]

The diagnosis of septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis is made with synovial fluid analysis Synovial Fluid Analysis Rheumatoid Arthritis.

• Should be attempted before antibiotics are given
• A positive Gram stain Gram stain Klebsiella and/or culture confirms the diagnosis.
• A purulent aspirate gives a presumptive diagnosis:
  • WBC count > 50,000 cells/μL
  • Neutrophils Neutrophils Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes. Innate Immunity: Phagocytes and Antigen Presentation predominance
• Nucleic acid amplification Nucleic acid amplification Laboratory techniques that involve the in-vitro synthesis of many copies of DNA or RNA from one original template. Septic Arthritis testing may be performed if N. gonorrhoeae N. gonorrhoeae A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of gonorrhea. Neisseria is suspected.
• Include an analysis for crystals to rule out gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout.
• Absence of organisms on Gram stain Gram stain Klebsiella and synovial fluid culture does not exclude the diagnosis of septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. 
• In PJI:^[14]
  • Consult the patient’s orthopedic surgeon.
  • Thresholds in synovial fluid analysis Synovial Fluid Analysis Rheumatoid Arthritis differ; the type of prosthesis and the time after implantation Implantation Endometrial implantation of embryo, mammalian at the blastocyst stage. Fertilization and First Week affect the cell count.

Laboratory evaluation^[6,7,12,13]

Laboratory studies that support the diagnosis:

• ↑ Erythrocyte sedimentation rate Erythrocyte Sedimentation Rate Soft Tissue Abscess ( ESR ESR Soft Tissue Abscess): ≥ 10 mm/hr
• ↑ C-reactive protein (CRP): ≥ 1.5 mg/dL
• ↑ WBC count
• Blood cultures (should always be obtained)
• Cervical, urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy, rectal, or oropharyngeal swabs for nucleic acid amplification Nucleic acid amplification Laboratory techniques that involve the in-vitro synthesis of many copies of DNA or RNA from one original template. Septic Arthritis test if N. gonorrhoeae N. gonorrhoeae A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of gonorrhea. Neisseria is suspected
• Renal and liver Liver The 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 function should be measured, as dysfunction may impact antibiotic choice or dosing.

Imaging^{[5–7,13,15]}

• Plain X-rays X-rays X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. X-rays:
  • Joint-space narrowing or widening
  • Subchondral bony changes, osteopenia Osteopenia Osteoporosis (especially in the later stages)
  • Periarticular soft tissue Soft Tissue Soft Tissue Abscess swelling Swelling Inflammation
  • Normal studies do not rule out septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis.
  • Can rule out other conditions under consideration (e.g., fractures) 
  • Gas visible within the joints suggests infection with E. coli or anaerobes Anaerobes Lincosamides.
• Ultrasound:
  • Identification Identification Defense Mechanisms of a joint effusion Joint Effusion Septic Arthritis
  • Can assist with aspiration of the effusion
• CT:
  • Evaluates soft tissue Soft Tissue Soft Tissue Abscess compartments, allowing differentiation from cellulitis Cellulitis Cellulitis is a common infection caused by bacteria that affects the dermis and subcutaneous tissue of the skin. It is frequently caused by Staphylococcus aureus and Streptococcus pyogenes. The skin infection presents as an erythematous and edematous area with warmth and tenderness. Cellulitis, myositis, and tenosynovitis
  • Most sensitive in detecting tissue gas
  • Able to show periosteal reaction and bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types erosions Erosions Corneal Abrasions, Erosion, and Ulcers
• MRI:
  • Most appropriate imaging method after initial study, especially when radiographs suggest joint effusion Joint Effusion Septic Arthritis
  • Sensitive for early identification Identification Defense Mechanisms of joint effusion Joint Effusion Septic Arthritis
  • Evaluates the extent of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types and soft-tissue abnormalities
  • Assesses for associated osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis (which is important to detect, as this may need surgery)
  • Particularly helpful in evaluating sacroiliac and sternoclavicular joint Sternoclavicular Joint Examination of the Upper Limbs infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
  • Not as sensitive as CT in detecting soft tissue Soft Tissue Soft Tissue Abscess gas

Management

Components of management include: (1) early identification Identification Defense Mechanisms and treatment, (2) antibiotic therapy, and (3) joint aspiration/drainage (with orthopedic consultation, as indicated).

Antibiotic therapy

Antibiotic selection Selection Lymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen. B cells: Types and Functions is based on the initial Gram stain Gram stain Klebsiella and tailored based on culture data. Rapid joint destruction can occur in septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis (of a native joint), so broad-spectrum Broad-Spectrum Fluoroquinolones antibiotic coverage is often required initially. 

Empiric regimen if Gram stain Gram stain Klebsiella is negative (no organism seen, but synovial fluid cell count elevated):^{[6,9,11,13,16–21]}

• Concerning organisms:
  • S. aureus S. aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Staphylococcus 
  • Gram-negative organisms (especially in trauma patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship and immunocompromised immunocompromised A 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 patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship and those with IV drug use or indwelling catheters Indwelling catheters Catheters designed to be left within an organ or passage for an extended period of time. Pseudomonas)
• Vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides 15–20 mg/kg/dose every 8–12 hours, with adjustment made based on therapeutic monitoring
• 3rd- or 4th-generation cephalosporin Cephalosporin Multidrug-resistant Organisms and Nosocomial Infections (added to vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides):
  • Traumatic bacterial arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis, either:
    • Ceftriaxone Ceftriaxone A broad-spectrum cephalosporin antibiotic and cefotaxime derivative with a very long half-life and high penetrability to meninges, eyes and inner ears. Cephalosporins 2 g IV daily 
    • Cefotaxime Cefotaxime Semisynthetic broad-spectrum cephalosporin. Cephalosporins 2 g IV every 8 hours
  • High risk for Pseudomonas Pseudomonas Pseudomonas is a non-lactose-fermenting, gram-negative bacillus that produces pyocyanin, which gives it a characteristic blue-green color. Pseudomonas is found ubiquitously in the environment, as well as in moist reservoirs, such as hospital sinks and respiratory equipment. Pseudomonas infection, either:
    • Ceftazidime Ceftazidime Semisynthetic, broad-spectrum antibacterial derived from cephaloridine and used especially for pseudomonas and other gram-negative infections in debilitated patients. Cephalosporins 2 g IV every 8 hours
    • Cefepime Cefepime A fourth-generation cephalosporin antibacterial agent that is used in the treatment of infections, including those of the abdomen, urinary tract, respiratory tract, and skin. It is effective against pseudomonas aeruginosa and may also be used in the empiric treatment of febrile neutropenia. Cephalosporins 2 g IV every 8–12 hours 

Gram-positive Gram-Positive Penicillins cocci Cocci Bacteriology:^{[6,10,11,13,22–29]}

• Empiric vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides
• If cultures grow MSSA:
  • Cefazolin Cefazolin A semisynthetic cephalosporin analog with broad-spectrum antibiotic action due to inhibition of bacterial cell wall synthesis. It attains high serum levels and is excreted quickly via the urine. Cephalosporins 2 g IV every 8 hours
  • Nafcillin Nafcillin A semi-synthetic antibiotic related to penicillin. Staphylococcal Scalded Skin Syndrome (SSSS) 1.5–2 g IV every 4–6 hours
  • Dicloxacillin Dicloxacillin One of the penicillins which is resistant to penicillinase. Penicillins 500 mg by mouth every 6 hours
  • Flucloxacillin 2 g IV every 6 hours (not available in the US)
  • Clindamycin Clindamycin An antibacterial agent that is a semisynthetic analog of lincomycin. Lincosamides 600 mg by mouth or IV 3 times a day or vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides if penicillin-allergic
• If cultures grow MRSA MRSA A strain of Staphylococcus aureus that is non-susceptible to the action of methicillin. The mechanism of resistance usually involves modification of normal or the presence of acquired penicillin binding proteins. Staphylococcus:
  • Vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides
  • Daptomycin Daptomycin A cyclic lipopeptide antibiotic that inhibits gram-positive bacteria. Lipopeptides and Lipoglycopeptides 6 mg/kg/day IV
  • Linezolid Linezolid An oxazolidinone and acetamide derived anti-bacterial agent and protein synthesis inhibitor that is used in the treatment of gram-positive bacterial infections of the skin and respiratory tract. Oxazolidinones 600 mg by mouth or IV every 12 hours
  • Clindamycin Clindamycin An antibacterial agent that is a semisynthetic analog of lincomycin. Lincosamides 600 mg by mouth or IV 3 times a day
  • Trimethoprim Trimethoprim The sulfonamides are a class of antimicrobial drugs inhibiting folic acid synthesize in pathogens. The prototypical drug in the class is sulfamethoxazole. Although not technically sulfonamides, trimethoprim, dapsone, and pyrimethamine are also important antimicrobial agents inhibiting folic acid synthesis. The agents are often combined with sulfonamides, resulting in a synergistic effect. Sulfonamides and Trimethoprim– sulfamethoxazole Sulfamethoxazole A bacteriostatic antibacterial agent that interferes with folic acid synthesis in susceptible bacteria. Its broad spectrum of activity has been limited by the development of resistance. Sulfonamides and Trimethoprim: 2 double-strength tablets 2 times daily

Gram-negative bacilli Bacilli Shigella:^[11,13,30]

• Empiric options:
  • 3rd- or 4th-generation cephalosporins Cephalosporins Cephalosporins are a group of bactericidal beta-lactam antibiotics (similar to penicillins) that exert their effects by preventing bacteria from producing their cell walls, ultimately leading to cell death. Cephalosporins are categorized by generation and all drug names begin with “cef-” or “ceph-.” Cephalosporins (e.g., ceftazidime Ceftazidime Semisynthetic, broad-spectrum antibacterial derived from cephaloridine and used especially for pseudomonas and other gram-negative infections in debilitated patients. Cephalosporins, cefepime Cefepime A fourth-generation cephalosporin antibacterial agent that is used in the treatment of infections, including those of the abdomen, urinary tract, respiratory tract, and skin. It is effective against pseudomonas aeruginosa and may also be used in the empiric treatment of febrile neutropenia. Cephalosporins)
  • Aztreonam Aztreonam The carbapenems and aztreonam are both members of the bactericidal beta-lactam family of antibiotics (similar to penicillins). They work by preventing bacteria from producing their cell wall, ultimately leading to bacterial cell death. Carbapenems and Aztreonam 2 g IV every 8 hours
• For P. aeruginosa P. aeruginosa A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. Aeruginosa is a major agent of nosocomial infection. Pseudomonas (especially in the setting of sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock, neutropenia Neutropenia Neutrophils are an important component of the immune system and play a significant role in the eradication of infections. Low numbers of circulating neutrophils, referred to as neutropenia, predispose the body to recurrent infections or sepsis, though patients can also be asymptomatic. Neutropenia, or increased risk of resistance Resistance Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow. Ventilation: Mechanics of Breathing), add 1 of the following:
  • Fluoroquinolone
  • Gentamicin Gentamicin Aminoglycosides

Gram-negative cocci Cocci Bacteriology:[6,9,11,13]

• Ceftriaxone Ceftriaxone A broad-spectrum cephalosporin antibiotic and cefotaxime derivative with a very long half-life and high penetrability to meninges, eyes and inner ears. Cephalosporins (management of choice in N. gonorrhoeae N. gonorrhoeae A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of gonorrhea. Neisseria infection)
• Aminoglycosides Aminoglycosides Aminoglycosides are a class of antibiotics including gentamicin, tobramycin, amikacin, neomycin, plazomicin, and streptomycin. The class binds the 30S ribosomal subunit to inhibit bacterial protein synthesis. Unlike other medications with a similar mechanism of action, aminoglycosides are bactericidal. Aminoglycosides

Duration of therapy depends on additional factors:^[6]

• With negative blood cultures:
  • 2 weeks of parenteral antibiotics
  • Additional 1–2 weeks of oral antibiotics
• With positive blood cultures: 4 weeks of parenteral antibiotics
• P. aeruginosa P. aeruginosa A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. Aeruginosa is a major agent of nosocomial infection. Pseudomonas infection: 4–6 weeks

Antibiotics for PJI:^[7,14]

• Antibiotic options are affected by several factors, including the duration of symptoms (acute vs. chronic PJI).
• Additionally, surgical procedures are involved:
  • Debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome and retention of prosthesis, OR
  • Resection arthroplasty Arthroplasty Surgical reconstruction of a joint to relieve pain or restore motion. Osteoarthritis with or without planned stage reimplantation
• Ultimately, the complex treatment is decided on by the orthopedic surgeon in consultation with other specialties (e.g., infectious disease).
• See Infectious Disease Society of America guideline for additional details.

Surgical interventions

Joint drainage Joint Drainage Septic Arthritis:^[5–7]

• Involve orthopedic team early:
  • +/– Cardiothoracic team if sternoclavicular joint Sternoclavicular Joint Examination of the Upper Limbs involvement
  • Required if PJI suspected
• Generally warranted in all patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship
• Often requires repeated drainage to dryness until cultures are negative and effusions resolve.
• Options:
  • Needle aspiration Needle aspiration Using fine needles (finer than 22-gauge) to remove tissue or fluid specimens from the living body for examination in the pathology laboratory and for disease diagnosis. Peritonsillar Abscess
  • Arthroscopic drainage Arthroscopic Drainage Septic Arthritis (e.g., for hip, shoulder joint Shoulder joint The articulation between the head of the humerus and the glenoid cavity of the scapula. Examination of the Upper Limbs)
  • Arthrotomy Arthrotomy Septic Arthritis (open surgery) is indicated when:
    • Repeated percutaneous drainage Percutaneous Drainage Echinococcus/Echinococcosis fails to control joint effusion Joint Effusion Septic Arthritis
    • Joint is technically difficult to aspirate
    • Adjacent soft tissues are infected
  • Contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation:
    • The only direct definitive contraindication to joint aspiration is an underlying abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease. 
    • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs is a relative contraindication (due to risk of hemarthrosis Hemarthrosis Bleeding into the joints. It may arise from trauma or spontaneously in patients with hemophilia. Hemophilia) but should be balanced against the much higher risk associated with not detecting septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. 
• Aspiration technique:
  • If unable to obtain fluid on initial aspiration, consider:
    • Using a larger-gauge needle and a smaller syringe (generates a greater pressure differential so improves chances of obtaining fluid)
    • Compression Compression Blunt Chest Trauma on the contralateral side of the affected joint while gently rotating the needle
    • Ultrasound-guided aspiration 

Surgical debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with prosthesis:^[6,14]

• Always refer a patient with a possibly infected prosthetic joint to an orthopedic surgeon.
• Debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome with preservation of prosthesis:
  • Infection occurs within 30 days of implantation Implantation Endometrial implantation of embryo, mammalian at the blastocyst stage. Fertilization and First Week.
  • Presentation within 3 weeks of symptom onset
  • No evidence of draining sinus tract
• Debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome with removal of prosthesis:
  • Prosthesis is removed and a joint spacer placed.
  • 6-week course of antibiotics
  • Eventual replacement with a new joint prosthesis Joint prosthesis Prostheses used to partially or totally replace a human or animal joint. Soft Tissue Abscess

Recommendations specific to primary care and emergency department^[6,7]

• The most common hot and tender joint to present is the metatarsophalangeal joint Metatarsophalangeal Joint Foot: Anatomy of the great toe. This is nearly exclusively gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout and can be diagnosed clinically. 
• Never inject intra-articular steroids Steroids A 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 into a joint for which septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis is part of the differential diagnosis. 
• Admit patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with suspected sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock to the hospital. 
• The skills necessary to aspirate a joint in the hospital will likely be held by specialists and trainees in emergency medicine, orthopedics, and rheumatology. 

Complications^[8]

This list of complications is not exhaustive.

• Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock and death
• Osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis 
• Secondary osteoarthritis Secondary Osteoarthritis Osteoarthritis 

Differential Diagnosis

• Reactive arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis: a seronegative, autoimmune spondyloarthropathy Spondyloarthropathy Ankylosing Spondylitis that is often precipitated by a GI or genitourinary infection. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with an asymmetric oligoarthritis Oligoarthritis Ankylosing Spondylitis, enthesopathy Enthesopathy Reactive Arthritis, dactylitis Dactylitis Ankylosing Spondylitis, and/or sacroiliitis Sacroiliitis Inflammation of the sacroiliac joint. It is characterized by lower back pain, especially upon walking, fever, uveitis; psoriasis; and decreased range of motion. Many factors are associated with and cause sacroiliitis including infection; injury to spine, lower back, and pelvis; degenerative arthritis; and pregnancy. Ankylosing Spondylitis. The diagnosis is clinical, and a negative synovial Gram stain Gram stain Klebsiella and culture will help rule out septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Management includes NSAIDs NSAIDS Primary vs Secondary Headaches, disease-modifying antirheumatic drugs Disease-modifying antirheumatic drugs Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs) ( DMARDs DMARDs Disease-modifying antirheumatic drugs are antiinflammatory medications used to manage rheumatoid arthritis. The medications slow, but do not cure, the progression of the disease. The medications are classified as either synthetic or biologic agents and each has unique mechanisms of action and side effects. Disease-Modifying Antirheumatic Drugs (DMARDs)), and treatment of an active infection.
• Gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis: an arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis due to precipitation of monosodium urate crystals Monosodium Urate Crystals Gout in the joints. The condition is characterized by acute, painful, recurring, monoarticular arthritis Monoarticular Arthritis Septic Arthritis. The most commonly involved joint is the 1st metatarsophalangeal joint Metatarsophalangeal Joint Foot: Anatomy. The diagnosis is made with identification Identification Defense Mechanisms of negatively birefringent, needle-shaped crystals in the synovial fluid, which differentiates gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout from septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Therapies include NSAIDs NSAIDS Primary vs Secondary Headaches, colchicine Colchicine A major alkaloid from colchicum autumnale l. And found also in other colchicum species. Its primary therapeutic use is in the treatment of gout. Gout Drugs, steroids Steroids A 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, and uric acid Uric acid An oxidation product, via xanthine oxidase, of oxypurines such as xanthine and hypoxanthine. It is the final oxidation product of purine catabolism in humans and primates, whereas in most other mammals urate oxidase further oxidizes it to allantoin. Nephrolithiasis reduction with allopurinol Allopurinol A xanthine oxidase inhibitor that decreases uric acid production. It also acts as an antimetabolite on some simpler organisms. Gout Drugs.
• Pseudogout: intra-articular calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes pyrophosphate deposition. The etiology is not clear. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with acute flares of joint swelling Swelling Inflammation, warmth, and pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. Pseudogout usually affects larger joints, such as the knee. Diagnosis is with identification Identification Defense Mechanisms of positively birefringent and rhomboid crystals in the synovial fluid, which differentiates pseudogout from septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Management includes NSAIDs NSAIDS Primary vs Secondary Headaches, corticosteroids Corticosteroids Chorioretinitis, and colchicine Colchicine A major alkaloid from colchicum autumnale l. And found also in other colchicum species. Its primary therapeutic use is in the treatment of gout. Gout Drugs.
• Osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis ( OA OA Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis): arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis due to cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology destruction and changes in the subchondral bone Subchondral Bone Osteochondritis Dissecans. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship develop gradual joint pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, stiffness lasting < 30 minutes, and decreased range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs. Physical exam may reveal crepitus Crepitus Osteoarthritis with joint motion and osteophyte Osteophyte Bony outgrowth usually found around joints and often seen in conditions such as arthritis. Osteoarthritis formation. The diagnosis is clinical. Synovial fluid will be non-inflammatory, which differentiates OA OA Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis from septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Management includes analgesics, glucocorticoid intra-articular injections, and surgery for advanced disease.
• Osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis: an infection of the bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types most commonly caused by S. aureus S. aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Staphylococcus. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, redness Redness Inflammation, and swelling Swelling Inflammation of the affected site and may have associated symptoms such as fever Fever Fever 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 chills Chills The sudden sensation of being cold. It may be accompanied by shivering. Fever. Laboratory values will demonstrate elevated WBC, CRP, and ESR ESR Soft Tissue Abscess in most cases. The most sensitive and specific imaging modality to diagnose osteomyelitis Osteomyelitis Osteomyelitis is an infection of the bone that results from the spread of microorganisms from the blood (hematogenous), nearby infected tissue, or open wounds (non-hematogenous). Infections are most commonly caused by Staphylococcus aureus. Osteomyelitis is MRI. Management requires long-term antibiotics and potential surgical debridement Debridement The removal of foreign material and devitalized or contaminated tissue from or adjacent to a traumatic or infected lesion until surrounding healthy tissue is exposed. Stevens-Johnson Syndrome.
• Lyme disease Lyme disease Lyme disease is a tick-borne infection caused by the gram-negative spirochete Borrelia burgdorferi. Lyme disease is transmitted by the black-legged Ixodes tick (known as a deer tick), which is only found in specific geographic regions. Patient presentation can vary depending on the stage of the disease and may include a characteristic erythema migrans rash. Lyme Disease: a tick-borne infection caused by the Gram-negative spirochete Spirochete Treponema is a gram-negative, microaerophilic spirochete. Owing to its very thin structure, it is not easily seen on Gram stain, but can be visualized using dark-field microscopy. This spirochete contains endoflagella, which allow for a characteristic corkscrew movement. Treponema Borrelia burgdorferi Borrelia burgdorferi A specific species of bacteria, part of the borrelia burgdorferi group, whose common name is lyme disease spirochete. Borrelia. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with late disease may develop a migratory polyarthritis Migratory Polyarthritis Rheumatic Fever, particularly in large joints. An erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion migrans rash Rash Rocky Mountain Spotted Fever as well as neurologic, cardiac, and ocular manifestations may also be present. Synovial fluid analysis Synovial Fluid Analysis Rheumatoid Arthritis and serologic testing can confirm a Lyme infection and will differentiate the disease from septic arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Antibiotic therapy is used for treatment.