Infectious Disease Flashcards
Malignant otitis externa
Symptoms: ear discharge and severe ear pain that radiates to the TMJ; also granulation tissue in the ear canal
Risk factors: diabetes mellitus and other immunosuppressing conditions
- not responsive to topical antibiotics
HIV post-exposure prophylaxis
- Initiate therapy within first few hours and continue to treat for 28 days
3 drug regimen: 2 NRTIs (tenofovir and emtracitabine)
integrase strand transfer inhibitor (raltegravir), protease inhibitor, or NNRTI
- Risk of seroconversion is
Acute pyelonephritis treatment
Uncomplicated: Mild to moderate - TMX or fluoroquinolones (cipro)
Severe - IV ceftriaxone, TMX, or fluoroquinolones (cipro or levo)
Complicated - indwelling catheter, urinary obstruction or retention, recent urologic procedure or hospital-aquired infection, renal impairment with azotemia, immunosuppression, and diabetes
IV antibiotics and hospitalization
Mild to moderate - ceftriaxone, cefepime, fluoroquinolones (levo and cipro)
Severe - ampicillin-sulbactam, ticarcillin-clavulanate, piperacillin-tazobactam, meropenem, imipenem, aztreonam (+or- gentamicin)
- Diabetic pts are started on IV Abs and then switched to oral after 48-72 hours. Oral antibiotics are continued for 10 - 14 days.
Histoplasmosis
- Present in soil, bird and bat droppings; no human to human spread
Immunocompetent: asymptomatic or mild pulmonary disease
Immunocompromised: pancytopenia, hepatosplenomegaly, and adenopathy - Reticulonodular or cavitary pneumonia, mucocutaneous ulcers
Diagnosis: pancytopenia, elevated LDH and ferritin, elevated liver enzymes, positive urine or serum antigen, blood culture, or microscopy
Treatment: Immunocompetent - no treatment or oral itraconazle
Immunocompromised, severe infection, or disseminated disease - amphotericin B w/ switch to itraconazole after initial response
-Seen in AIDS patients with CD4 counts
Crytptococcal meningoencephalitis
- seen in HIV pts with CD4or= 1 yr)
- Wait 2-8 wks after induction therapy before starting antiretrovirals due to risk of immune reconstitution syndrome.
- May require serial lumbar punctures to reduce pressures.
Invasive aspergillosis
- Occurs in immunocompromised pts
Symptoms: fever, cough, dyspnea, hemoptysis
CXR: cavitary lesion
CT scan: pulmonary nodules wi/ halo sign or air crescent
Bacillary angiomatosis
- Caused by Bartonella hensalae and Bartonella quintana (Gram negative bacillus)
- Common in immunosuppressed pts
Symptoms: exophytic purple skin masses, hepatomegaly and intrahepatic lesions, fever, weight loss, abdominal pain
Treatment: oral erythromycin
- High risk of hemorrhage during liver biopsy.
Isoniazid for TB
- mild, subclinical liver injury is common with severe hepatitis only affecting a small number of people.
- Continue treatment in healthy pts with mild liver injury and monitor closely.
- With severe hepatitis, switch to second-line therapy.
Treatment of Lyme disease in pregnancy
Oral amoxicillin
Acute HIV infection
Symptoms: fever, lymphadenopathy, sore throat, arthralgias, macular rash, GI symptoms
- HIV Ab may be negative (not yet seroconverted)
Prophylaxis criteria for Lyme disease
Must meet all 5:
- Attached tick is an adult or nymphal Ixodes scapularis
- tick attached for >or= to 36 hours or its engorged
- Prophylaxis started within 72 hrs of removal
- Local Borrelia burgdorferi infection rate >20%
- no contraindications to doxycycline
Rubella
Congenital: sensorineural hearing loss, intellectual disability, cardiac anomalies, cataracts, glaucoma
Children: low-grade fever, conjunctivitis, coryza, cervical lymphadenopathy, Forschheimer spots (petechaie on the soft palate), cephalocaudal spread of blanching, erythematous maculopapular rash (spares the soles and palms)
Adults and adolescents: same as children + arthralgias/arthritis
Diagnosis: PCR, acute and convalescent serology for anti-rubella IgM and IgG
Prevention: Live attenuated vaccine
Treatment: supportive
Complications: postinfectious encephalitis
Measels
- Higher fever (>104), more gradual cranial-caudal spread of the rash, arthritis is not present
Paroxysmal nocturnal hemoglobinuria
Symptoms: fatigue, cytopenia, and venous thrombosis (abdominal, cerebral)
Diagnosis: pancytopenia, elevated LDH and decreased haptoglobin, indirect hyperbilirubinemia, hemoglobinuria, absence of CD55 and CD59 (lack of glycosylphosphatidylinositol which prevents complement inhibitory proteins on the cell surface from working).
- Absence allows the membrane attack complex to form.
Treatment: iron and folate supplementation and eculizumab
(inhibits complement activation)
- Both intravascular and extravascular hemolysis.
- Symptoms in the 4th decade.
Tuberculosis
Infection: accumulation of neutrophils, macrophages and bacilli in the lower lung forms a tubercle w/ associated lympadenopathy forming a Gohn complex —–> cell-mediated immune response w/ latent TB
Reactivation: cough, weight loss, fever, night sweats
CXR - upper lobe infiltrates w/ cavities
