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lnfectious Disease Genital Warts Prevention The HPV vaccine protects against HPV types that cause genital warts and cervical cancer (see General Internal Medicine) Diagnosis Genital warts are typically painless, flesh colored, and exophytic. Diagnosis is made clinically. Treatment Most infections clear spontaneously. Treatment does not prevent HpV transmission. patient-applied agents include podofilox (podophyllotoxin), imiquimod, and sinecatechins. Physician-administered treatments include podophyllin resin, trichloroacetic acid, cryotherapy, and surgical removal. Osteomyelitis Diagnosis Microorganisms infect bone by o contiguous spread from adjacent soft tissue or joints; usually polymicrobial o hematogenous seeding; most commonly identified is Stophylococcus oureus o direct inoculation as a result of surgery or trauma; usually polymicrobial Pain at the involved site without systemic symptoms is the typical presentation. Consider osteomyelitis when chronic wounds do not respond to appropriate therapy. Patients who have undergone total joint arthroplasty and have new or unresolved joint pain may have a prosthetic joint infection. STUDY TABLE: Categorization and Characterization of Osteomyelitis Category Characteristics Acute hematogenous osteomyelitis lnfection of intervertebral disk space and two adjacent vertebrae Contiguous osteomyelitis Patients with a diabetic foot ulcer that is deep (presence of exposed bone), large (>2 cm in diameter), or chronic (nonhealing after 6 weeks of standard care) Following foot puncture wound Pseudomonas is frequently isolated following puncture wounds through the rubber sole of a shoe Sternal osteomyelitis Unstable sternum and fever after thoracic surgery Sternoclavicular joint osteomyelitis lnjection drug use Sickle cell disease Most commonly caused by Salmonella species and 5. aureus

Following foot puncture wound Pseudomonas is frequently isolated following puncture wounds through the rubber sole of a shoe Sternal osteomyelitis Unstable sternum and fever after thoracic surgery Sternoclavicular joint osteomyelitis lnjection drug use Sickle cell disease Most commonly caused by Salmonella species and 5. aureus Testing Select radiography as the first imaging test; it can confirm the diagnosis iftypical findings are present but cannot exclude the diagnosis if negative. If plain radiography is not diagnostic, select MRI; if contraindicated, select CT. Half of patients with acute hematogenous osteomyelitis will have positive blood cultures. Bone biopsy is the definitive diagnostic study for osteomyelitis. A positive blood culture obviates the need fbr a bone biopsy In stable chronic osteomyelitis (absent cellulitis or bacteremia), withhold antimicrobial therapy until deep bone cultures have been obtained. 243

lnfectious Disease S. oureus (including MRSA) is the most common cause of vertebral osteomyelitis. MRI is the most sensitive imaging modality to detect vertebral osteomyelitis. Patients with imaging studies suggestive of vertebral osteomyelitis but negative blood cultures should undergo a CT-guided percutaneous needle biopsy. DOil'T BE TRICKED r Do not obtain sinus tract and wound drainage cultures. Treatment For all patients: o administration of culture guided antimicrobials (usually 4-6 weeks) . surgical debridement (if warranted) . removal of orthopedic prosthetic devices (if feasible) Patients with vertebral osteomyelitis and neurologic compromise or spinal instability should undergo evaluation for immediate surgical intervention. Patients with sepsis, neurologic deficit, spinal instability, or epidural abscess should receive empiric antibiotic therapy. Vancomycin or dapto mycin plus ceftriaxone, ceftazidime, cefepime, or a fluoroquinolone are appropriate choices. For diabetic foot infections with osteomyelitis, bone biopsy and culture directs antibiotic selection. In patients with poor arterial vascular supply, also choose revascularization. DOil'T BE TRICKED . Surgery is not needed for uncomplicated hematogenous vertebral Hematogenous Osteomyelitis: MRI shows moderate destruction of osteomyelitis. the inferior L3 and superior L4 vertebral bodies compatible with osteo- . A positive MRI persists long after effective therapy for osteomyelitis; myelitis. Moderate nanowi ng of the thecal sac is seen at th is level owi ng to retropulsion of an enhancing bony fragment. do not obtain follow-up MRI in patients improving clinically. TESTYOURSELF A 60 year old man has pain in his lower thoracic spine that began l0 days ago following a urinary tract infection. Temperature is 37 .9 "C (100.2 "F). Point tenderness of the lower thoracic spine is present. ANSWER: For diagnosis, choose acute hematogenous osteomyelitis of the vertebral spine. For management, obtain urine and blood cultures and spine MRI.

TESTYOURSELF A 60 year old man has pain in his lower thoracic spine that began l0 days ago following a urinary tract infection. Temperature is 37 .9 "C (100.2 "F). Point tenderness of the lower thoracic spine is present. ANSWER: For diagnosis, choose acute hematogenous osteomyelitis of the vertebral spine. For management, obtain urine and blood cultures and spine MRI. Fever of Unknown Origin Diagnosis Fever of unknown origin is characterized by a temperature >38.3 oC (100.9 .F) for at least 3 weeks that remains undiagnosed after two outpatient visits or 3 days of inpatient evaluation. 244

lnfectious Disease STUpY ?ABLE: Categories and Common Causes of Fever of Unknown Origin Category Common Causes \-tasstc lnfection (primary CMV infection, endocarditis, TB, abscesses, complicated UTI), neoplasm, connective tissue disease, endocrine diseases Health care-associated Drug fevel septic thrombophlebitis, PE, sinusitis, postoperative complications (occult abscesses), Clostridi oides diffici I e, device- or procedure-related endocarditis Neutropenic Aspergillosis, candidiasis, drug fevel PE, underlying malignancy; cause not documented in 40"/o-607o of cases HIV-associated CMV, cryptococcosis, TB and nontuberculous Mycobacteria infection, toxoplasmosis, lymphoma, lRlS Drug induced fever may occur at any time but usually appears days to weeks after initiation of a new drug. Initial studies include at least three sets of blood culture, an ESR, TB testing, and serolo$/ for HIV; it is reasonable to perform chest imaging as initial diagnostic imaging. Primary I m m u nodeficiency Synd romes Diagnosis and Testing The most common primary immunodeficiency is IgA deficiency. Most patients with isolated IgA deficiency are asympto matic but may present with recurrent sinopulmonary infections or giardiasis and have an increased risk for autoimmune disorders, including RA and SLE. Patients are at high risk for transfusion reactions because of the development of anti-IgA antibodies. CVID is characterized by low levels of one or more immunoglobulin classes or subclasses. Findings include: ' hypogammaglobulinemia . recurrent bacterial upper and lower respiratory infections (including bronchiectasis) r predilection for infection with encapsulated bacteria (pneumococcus, Hoemophilus) o infectious diarrhea, specifically Giardia infection Measure serum IgM, IgA, and IgG (all low), as well as IgG subclasses (variably low), and then abilig to mount an antibody response to tetanus toxoid and pneumococcal polysaccharide vaccine (absent). Treatment lV immune globulin is first-line therapy for CVID. N4ost patients with selective IgA deficiency do not require treatment. DOI{'T BE TRICKED . Live vaccines should be avoided in persons with CVID

Measure serum IgM, IgA, and IgG (all low), as well as IgG subclasses (variably low), and then abilig to mount an antibody response to tetanus toxoid and pneumococcal polysaccharide vaccine (absent). Treatment lV immune globulin is first-line therapy for CVID. N4ost patients with selective IgA deficiency do not require treatment. DOI{'T BE TRICKED . Live vaccines should be avoided in persons with CVID TESTYOURSETF A 37-year old woman has had eight episodes of documented sinusitis annually for the past 15 years. She had a single episode of pneumonia as a child. ANSWER: For diagnosis, choose CVID. For management, choose measurement of serum immunoglobulin levels and, if low measurement of antibody response to pneumococcal and tetanus vaccines. 245