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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, but a variety of organisms have been linked to osteomyelitis. The majority of patients present with pain, redness, and swelling of the affected site, and may have associated symptoms such as fever and chills. Laboratory values will demonstrate elevated WBC, CRP, and erythrocyte sedimentation rate ( ESR ESR Soft Tissue Abscess) in most cases. The most sensitive and specific imaging modality to diagnose osteomyelitis is MRI. Management may require 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.

Last updated: Jul 6, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Epidemiology and Etiology

Epidemiology

  • Overall 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 is unknown.
    • May account for approximately 50,000 cases annually in the United States
    • Higher 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 in developing countries
  • Males > females
  • Non-hematogenous osteomyelitis is more common in adults.
  • Hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases osteomyelitis is more common in children.
    • Long 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 osteomyelitis is the most common subtype in children.
    • Vertebral osteomyelitis is the most common subtype in adults.

Etiology and classification

Osteomyelitis is classified based on the route of infection.

Non-hematogenous osteomyelitis (80% of cases):

  • Direct inoculation of bacteria Bacteria Bacteria 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 due to: 
    • Surgery
    • Prosthetic devices
    • Trauma
    • Hardware for fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures fixation
    • Soft tissue Soft Tissue Soft Tissue Abscess infection
  • Polymicrobial:
    • Staphylococcus Staphylococcus Staphylococcus is a medically important genera of Gram-positive, aerobic cocci. These bacteria form clusters resembling grapes on culture plates. Staphylococci are ubiquitous for humans, and many strains compose the normal skin flora. Staphylococcus aureus (present in > 50% of cases)
    • 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
    • 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
    • Gram-negative bacteria gram-negative bacteria Bacteria which lose crystal violet stain but are stained pink when treated by gram’s method. Bacteriology
    • Anaerobic bacteria Bacteria Bacteria 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

Hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases osteomyelitis (20% of cases):

  • Bacteria Bacteria Bacteria 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 spread via blood supply from the primary site of infection.
  • Monomicrobial: 
    • 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 (most common)
    • 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
    • Enteric gram-negative bacteria gram-negative bacteria Bacteria which lose crystal violet stain but are stained pink when treated by gram’s method. Bacteriology
    • 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 aeruginosa
    • Serratia Serratia A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in the natural environment (soil, water, and plant surfaces) or as an opportunistic human pathogen. Acute Cholangitis
    • 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
    • Mycobacterium Mycobacterium Mycobacterium is a genus of the family Mycobacteriaceae in the phylum Actinobacteria. Mycobacteria comprise more than 150 species of facultative intracellular bacilli that are mostly obligate aerobes. Mycobacteria are responsible for multiple human infections including serious diseases, such as tuberculosis (M. tuberculosis), leprosy (M. leprae), and M. avium complex infections. Mycobacterium tuberculosis Tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis
    • 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
    • Kingella
    • Bartonella henselae Bartonella henselae A species of gram-negative bacteria that is the etiologic agent of bacillary angiomatosis. This organism can also be a cause of cat-scratch disease in immunocompetent patients. Bartonella
    • Candida Candida Candida is a genus of dimorphic, opportunistic fungi. Candida albicans is part of the normal human flora and is the most common cause of candidiasis. The clinical presentation varies and can include localized mucocutaneous infections (e.g., oropharyngeal, esophageal, intertriginous, and vulvovaginal candidiasis) and invasive disease (e.g., candidemia, intraabdominal abscess, pericarditis, and meningitis). Candida/Candidiasis
    • Histoplasmosis Histoplasmosis Histoplasmosis is an infection caused by Histoplasma capsulatum, a dimorphic fungus. Transmission is through inhalation, and exposure to soils containing bird or bat droppings increases the risk of infection. Most infections are asymptomatic; however, immunocompromised individuals generally develop acute pulmonary infection, chronic infection, or even disseminated disease. Histoplasma/Histoplasmosis
    • Blastomycosis Blastomycosis Blastomycosis is an infection caused by inhalation of the spores of the fungus, Blastomyces. Blastomyces species thrive in moist soil and decaying material and are common in the Ohio and Mississippi River valleys and the Great Lakes regions of the United States and Canada. Although most patients are asymptomatic, some can develop pneumonia. Blastomyces/Blastomycosis
    • Coccidioidomycosis Coccidioidomycosis Coccidioidomycosis, commonly known as San Joaquin Valley fever, is a fungal disease caused by Coccidioides immitis or Coccidioides posadasii. When Coccidioides spores are inhaled, they transform into spherules that result in infection. Coccidioidomycosis is also a common cause of community-acquired pneumonia and can cause severe disease in the immunocompromised. Coccidioides/Coccidioidomycosis

Risk factors

  • Non-hematogenous: 
    • Trauma
    • Pressure ulcers
    • Foreign body Foreign Body Foreign Body Aspiration (prosthetics)
    • 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
    • Peripheral vascular disease 
    • Peripheral neuropathy Neuropathy Leprosy
  • Hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases:
    • Sickle cell anemia Anemia Anemia 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
    • 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
    • IV drug use
    • Indwelling catheters Indwelling catheters Catheters designed to be left within an organ or passage for an extended period of time. Pseudomonas
    • Immunodeficiency Immunodeficiency Chédiak-Higashi Syndrome
    • Endocarditis Endocarditis Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Endocarditis
Table: Common causes of osteomyelitis based on patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship’ underlying risk factors
Risk factors Infectious Infectious Febrile Infant agents
No specific risk factor 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
Prosthetic joint replacement Prosthetic Joint Replacement Septic Arthritis
  • 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
  • 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 (creates biofilms Biofilms Encrustations formed from microbes (bacteria, algae, fungi, plankton, or protozoa) embedded in an extracellular polymeric substance matrix that is secreted by the microbes. They occur on body surfaces such as teeth (dental deposits); inanimate objects, and bodies of water. Biofilms are prevented from forming by treating surfaces with dentifrices; disinfectants; anti-infective agents; and anti-fouling agents. Proteus on prosthetics)
Sickle cell anemia Anemia Anemia 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
  • 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
  • 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
Chronic granulomatous disease Granulomatous disease A defect of leukocyte function in which phagocytic cells ingest but fail to digest bacteria, resulting in recurring bacterial infections with granuloma formation. When chronic granulomatous disease is caused by mutations in the cybb gene, the condition is inherited in an X-linked recessive pattern. When chronic granulomatous disease is caused by cyba, ncf1, ncf2, or ncf4 gene mutations, the condition is inherited in an autosomal recessive pattern. Common Variable Immunodeficiency (CVID)
  • Serratia Serratia A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in the natural environment (soil, water, and plant surfaces) or as an opportunistic human pathogen. Acute Cholangitis
  • Aspergillus Aspergillus A genus of mitosporic fungi containing about 100 species and eleven different teleomorphs in the family trichocomaceae. Echinocandins
Vertebral osteomyelitis
  • M. tuberculosis Tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis (Pott’s disease)
  • 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
Sexually active, no other risk factors 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 (more likely to cause septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis than osteomyelitis)
Cat or dog bite Pasteurella multocida Pasteurella multocida A species of gram-negative, facultatively anaerobic, rod-shaped bacteria normally found in the flora of the mouth and respiratory tract of animals and birds. It causes shipping fever; hemorrhagic bacteremia; and intestinal disease in animals. In humans, disease usually arises from a wound infection following a bite or scratch from domesticated animals. Dog and Cat Bites
IV drug use or 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
  • 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
  • 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
  • Candida Candida Candida is a genus of dimorphic, opportunistic fungi. Candida albicans is part of the normal human flora and is the most common cause of candidiasis. The clinical presentation varies and can include localized mucocutaneous infections (e.g., oropharyngeal, esophageal, intertriginous, and vulvovaginal candidiasis) and invasive disease (e.g., candidemia, intraabdominal abscess, pericarditis, and meningitis). Candida/Candidiasis

Pathophysiology

Osteomyelitis is 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 that results from hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases or non-hematogenous spread of infectious Infectious Febrile Infant organisms.

  • Since 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 is usually resistant to infection, the following is usually required:
    • A large inoculum of organisms
    • 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 damage
    • Foreign material
  • The pathogenesis is poorly understood, but appears to be affected by several factors:
    • Host immune status
    • Underlying disease
    • Virulence Virulence The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its virulence factors. Proteus of the organisms:
      • Adherence
      • Defense mechanisms Defense mechanisms Defense mechanisms are normal subconscious means of resolving inner conflicts between an individual’s subjective moral sense and their thoughts, feelings, or actions. Defense mechanisms serve to protect the self from unpleasant feelings (anxiety, shame, and/or guilt) and are divided into pathologic, immature, mature, neurotic, and other types. Defense Mechanisms
      • Proteolytic activity
    • Vascularity and location 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 (e.g., the metaphysis Metaphysis Bones: Structure and Types 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 is commonly affected in hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases spread due to the rich vascular supply of the growth plates Growth Plates The area between the epiphysis and the diaphysis within which bone growth occurs. Osteosarcoma)
  • Timeline of infection:
    • Acute osteomyelitis evolves over days or weeks.
    • Chronic osteomyelitis persists over months to years and causes:
      • 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 ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage and necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage
      • 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 loss
      • Sinus tract formation
Pathophysiology of osteomyelitis

Pathophysiology of osteomyelitis:
A. Initial infection is localized to the cortical region.
B. There is progression into the subperiosteal space with lifting of the periosteum Periosteum Thin outer membrane that surrounds a bone. It contains connective tissue, capillaries, nerves, and a number of cell types. Bones: Structure and Types.
C. Diffuse infection occurs with sequestrum ( avascular Avascular Corneal Abrasions, Erosion, and Ulcers necrotic region) and sinus tract formation.

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Clinical Presentation

Acute osteomyelitis

  • Onset may be gradual.
  • Signs and symptoms:
    • 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
    • Localized swelling Swelling Inflammation
    • Warmth
    • Erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion
    • Dull pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways

Chronic osteomyelitis

  • Similar to acute osteomyelitis
  • Intermittent 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 pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Draining sinus tract (pathognomonic)
  • 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 are less common.

Physical exam

  • Check for tenderness to palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination over 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.
  • Assess for a nidus of infection:
    • Wound healing Wound healing Wound healing is a physiological process involving tissue repair in response to injury. It involves a complex interaction of various cell types, cytokines, and inflammatory mediators. Wound healing stages include hemostasis, inflammation, granulation, and remodeling. Wound Healing
    • High likelihood of osteomyelitis if it is possible to probe Probe A device placed on the patient’s body to visualize a target Ultrasound (Sonography) a chronic ulcer to 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 with a sterile Sterile Basic Procedures tool
  • Check sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology function.
  • Evaluate for diminished pulses.

Subtypes

Vertebral osteomyelitis:

  • Most common subtype of hematogenous Hematogenous Hepatocellular Carcinoma (HCC) and Liver Metastases osteomyelitis in adults
  • The lumbar spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy is most commonly affected.
  • Slow progression of symptoms:
    • Localized back pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
      • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma to the legs, abdomen, or groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination
      • Worsened with activity and at night
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology and sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology deficits with severe progression

Sternoclavicular and pelvic osteomyelitis:

Long 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 osteomyelitis:

  • Least common subtype in adults, but most common in children
  • Can present similar to septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis of a joint
  • Weight bearing on affected long bones Long bones Length greater than width. Bones: Structure and Types may be difficult.

Diagnosis

Laboratory evaluation

  • The following tests support the diagnosis of osteomyelitis:
  • The following cultures Cultures Klebsiella provide necessary identification Identification Defense Mechanisms and sensitivity data for the causative organism:
    • Blood cultures Cultures Klebsiella:
      • Positive in 50% of cases
      • Obtain prior to initiating antibiotics, if possible.
    • Tissue culture:
      • Should also be obtained prior to antibiotics, if possible
      • 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 biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma is the best way to identify the etiology.
      • Wound or abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease cultures Cultures Klebsiella are not reliable.

Imaging

  • 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:
    • 1st-line imaging modality
    • May not show changes in first 2 weeks of disease
    • A normal X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests does not rule out osteomyelitis.
    • Rules out metastasis Metastasis The transfer of a neoplasm from one organ or part of the body to another remote from the primary site. Grading, Staging, and Metastasis or fractures
    • Findings:
  • MRI:
    • Most sensitive and specific modality for osteomyelitis
    • Detects infection within 3–5 days of onset
    • Use is limited if surgical hardware is present.
    • Findings:
      • Bone marrow Bone marrow The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells. Bone Marrow: Composition and Hematopoiesis edema Edema Edema 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 is the earliest feature.
      • Cortical destruction
      • Soft tissue Soft Tissue Soft Tissue Abscess 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
    • Contrast enhancement helps distinguish abscess Abscess Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Chronic Granulomatous Disease margins and adjacent periosteum Periosteum Thin outer membrane that surrounds a bone. It contains connective tissue, capillaries, nerves, and a number of cell types. Bones: Structure and Types or soft tissue Soft Tissue Soft Tissue Abscess involvement.
  • 3-phase 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 scan:
    • Utilizes a radionuclide tracer, which accumulates in areas of osteoblast activity
    • 3 phases: 
    • Significant uptake in all 3 phases in osteomyelitis
  • Tagged WBC scan:
    • Blood is drawn from the patient, and autologous WBCs are labeled with a radionuclide tracer.
    • The tagged cells are then injected back into the patient, and the scan is performed.
    • Tagged WBCs accumulate at the site of infection.
    • Best used in distal extremities
    • Can be falsely positive if other inflammatory conditions are present in the area (e.g., fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures)

Management

Antibiotic therapy

  • Options:
  • May be sufficient in select patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with: 
    • Uncomplicated disease, particularly in children
    • Osteomyelitis of a diabetic foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
    • No underlying hardware or prosthetics

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

  • Often required if osteomyelitis is associated with:
    • Necrotic, purulent wound
    • Infected fluid collections
    • Injured or dead 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
    • Hardware/prosthetics
  • Removal of necrotic and diseased 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:
    • Culture of the wound 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 should be obtained during 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 to narrow antibiotic therapy.
    • Can allow placement of local antimicrobials
  • Hardware removal is often required.

Duration of treatment

  • Length of treatment varies greatly and is influenced by: 
    • Presence or absence of hardware
    • Options for 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 ability to remove all infected 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 treatment regimens average 6 weeks.
  • Long-term oral suppressive therapy should be considered for: 
    • Individuals with retained hardware
    • Necrotic 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/tissue that is not able to be debrided
  • Duration may be guided by CRP levels, but is often clinically determined by the resolution of symptoms.

Differential Diagnosis

  • Leukemia: the unregulated proliferation of WBCs that causes the lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs nodes and spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy to enlarge as well as bone marrow Bone marrow The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells. Bone Marrow: Composition and Hematopoiesis failure and anemia Anemia Anemia 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. Osteomyelitis and leukemia may present with similar constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis, such as night sweats Night sweats Tuberculosis, 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 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 pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways (especially in children). Cross-sectional imaging, peripheral blood smear Blood smear Myeloperoxidase Deficiency, and CBC with markedly increased WBC will provide the diagnosis. Management includes chemotherapy Chemotherapy Osteosarcoma.
  • Cancer metastasis Metastasis The transfer of a neoplasm from one organ or part of the body to another remote from the primary site. Grading, Staging, and Metastasis: cancers that metastasize to 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 include those of the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. , breast, kidney, thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy, and lung. The presentation may be similar to osteomyelitis, with long 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 pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways or back pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. However, constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis are rarely seen. On imaging, kidney, thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy, and lung cancer Lung cancer Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Lung Cancer can appear lytic. Biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma is the most definitive way to distinguish metastasis Metastasis The transfer of a neoplasm from one organ or part of the body to another remote from the primary site. Grading, Staging, and Metastasis from osteomyelitis. Management depends on the primary cancer type.
  • Charcot arthropathy Arthropathy Osteoarthritis: results from the combination of mechanical and vascular consequences of diabetic peripheral neuropathy Neuropathy Leprosy. This process triggers Triggers Hereditary Angioedema (C1 Esterase Inhibitor Deficiency) a local inflammatory response that causes pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, swelling Swelling Inflammation, and erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion of the affected joint. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship can also develop 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 wounds from their neuropathy Neuropathy Leprosy and progress to secondary osteomyelitis. X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests images will confirm the diagnosis. Management includes joint stabilization.
  • Chronic recurrent multifocal Multifocal Retinoblastoma osteomyelitis: a sterile Sterile Basic Procedures inflammatory disorder seen in children that can cause 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 damage if not treated. The pathology is poorly understood, but is presumed to be related to osteoclast dysfunction. Children may present with episodic or chronic pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways to 1 or multiple areas. The diagnosis is based on imaging. Laboratory values will be normal, unlike in osteomyelitis. Primary treatment involves NSAID NSAID Nonsteroidal antiinflammatory drugs (NSAIDs) are a class of medications consisting of aspirin, reversible NSAIDs, and selective NSAIDs. NSAIDs are used as antiplatelet, analgesic, antipyretic, and antiinflammatory agents. Nonsteroidal Antiinflammatory Drugs (NSAIDs) therapy. Immunosuppression may be needed if primary treatment fails.
  • Septic arthritis Septic arthritis Septic arthritis is an infection of the joint due to direct inoculation, contiguous extension, or hematogenous spread of infectious organisms into the joint space. This process causes an acute, inflammatory, monoarticular arthritis. Septic Arthritis: an infection of the joint that can be caused by bacteria Bacteria Bacteria 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 or other microorganisms. 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 acutely swollen, warm joint with limited 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. Constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis are present in some patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship. Diagnosis is made by synovial fluid analysis Synovial Fluid Analysis Rheumatoid Arthritis and culture. Unlike osteomyelitis, there are rarely bony changes on imaging. Management involves drainage, 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 antibiotic therapy.

References

  1. Momodu, I. I., Savaliya, V. (2021). Osteomyelitis. StatPearls. Retrieved March 3, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK532250/
  2. Lalani, T., Schmitt, S. K. (2021). Nonvertebral osteomyelitis in adults: clinical manifestations and diagnosis. In Baron, E. L. (Ed.), UpToDate. Retrieved March 3, 2021, from https://www.uptodate.com/contents/nonvertebral-osteomyelitis-in-adults-clinical-manifestations-and-diagnosis
  3. Sopirala, M. M. (2020). Pathogenesis of osteomyelitis. In Baron, E. L. (Ed.), UpToDate. Retrieved March 3, 2021, from, https://www.uptodate.com/contents/pathogenesis-of-osteomyelitis
  4. Osmon, D. R., Tande, A. J. (2021). Nonvertebral osteomyelitis in adults: treatment. In Baron, E. L. (Ed.), UpToDate. Retrieved March 3, 2021, from https://www.uptodate.com/contents/osteomyelitis-in-adults-treatment
  5. Spritzer, C. E. (2020). Approach to imaging modalities in the setting of suspected nonvertebral osteomyelitis. In Baron, E. L. (Ed.), UpToDate. Retrieved March 3, 2021, from https://www.uptodate.com/contents/approach-to-imaging-modalities-in-the-setting-of-suspected-nonvertebral-osteomyelitis
  6. Hordon, L. D. (2020). Diabetic neuropathic arthropathy. In Romain, P. L. (Ed.), UpToDate. Retrieved March 3, 2021, from https://www.uptodate.com/contents/diabetic-neuropathic-arthropathy
  7. Schmitt, S. (2020). Osteomyelitis. StatPearls. Retrieved March 4, 2021, from https://www.msdmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/infections-of-joints-and-bones/osteomyelitis
  8. Kishner, S., Hart, E. K., Nixon, G. C., and Laborde, J. M. (2020). Osteomyelitis. In Poduval, M. (Ed.), Medscape. Retrieved March 4, 2021, from https://emedicine.medscape.com/article/1348767-overview

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