HIV Opportunistic Infections Flashcards
Pneumocystis Jroveci Pneumonia
Diffuse interstitial pneumonia. Yeast-like fungus. Transmitted via inhalation of cysts. CD4<200. Ground glass appearance on CXR. Disc-shaped yeast on methane silver stain of lung tissue. ^LDH. Tx: TMP-SMX - start prophylaxis when CD4<200.
Esophageal Candidiasis
White, dimorphic, pseudohyphae and budding yeast in cold, germ tubes in warm.
Immunocompromised: persistent infection –> spread to esophagitis and disseminated infection can –> infective endocarditis.
AIDS-defining.
Presentation: retrosternal pain upon swallowing.
ORAL THRUSH NOT AIDS DEFINING.
T-cell deficient - superficial infection more likely.
Neutropenic - disseminated candidiasis (hematogenous)
Toxoplasmosis
Toxoplasma gondii.
AIDS –> brain abscess seen as ring-enhancing lesionS on MRI (also seen in primary CNS lymphoma- but usu just 1)
Cysts in meat, oocytes in cat feces, crosses placenta.
Tachyzoite on biopsy.
Tx: sulfadiazine + pyrimethamine.
Prophylaxis when CD4<100.
Toxoplasmosis in immunocompromised: cysts rupture and release tachyzoites.
- Chorioretinitis
- Encephalitis (most common cause of encephalitis in HIV)
- Pneumonitis (rare)
Cryptococcal Meningitis
Cyptococcus neoformans.
Narrow budding, heavily encapsulated yeast, not dimorphic.
Soil, pigeon droppings.
Inhalation; hematogenous dissemination to meninges.
Sabouraud agar.
India ink (clear halo) and mucicarmine (red inner capsule).
Polysaccharide capsular antigen +.
Causes cryptococcosis, cryptococcal meningitis, cryptococcal encephalitis (soap bubbles in brain).
Immunocompromised.
Cryptococcal meningitis CD4<100.
Indolent course - fever, malaise, headache.
Prophylaxis w fluconazole.
CMV Retinitis
CMV is icosahedral, enveloped, ds linear DNA herpesvirus.
Reactivation of latent infection when host becomes immunocompromised.
CD4<100.
Infected cells w owl eye inclusions.
Full thickness retinal necrosis and edema –> scar tissue. Tearing –> retinal detachment.
Exam: bilateral retinal hemorrhage and cotton wool exudates.
Mycobacterium Avium Complex (MAC)
Acid fast aerobic bacilli. (Usu found in macrophages when infected)
Mycolic acid in cell wall.
M avium or M intracellulare –> disseminated non-TB disease in AIDS.
Nonspecific presentation: cough, fatigue, malaise, weakness, dyspnea, chest discomfort, occasionally hemoptysis.
Distinguished from TB: anemia, ^Alk phos, ^ LDH.
Prophylaxis CD4<40 - clarithromycin or azithromycin.
Aspergillosis
A. fumigatus is mold w acute angled branching (V shape, <45) septate hyphae. Some species make aflatoxins assoc w hepatocellular carcinoma.
Causes invasive aspergillosis, esp in immunocompromised and those w chronic granulomatous disease.
Can cause aspergillomas in pre-existing lung cavities (esp after TB infections).
Allergic bronchopulmonary aspergillosis (ABPA): HSR assoc w asthma and CF. Ig-E mediated. Bronchiectasis and eosinophilia.
Invasive aspergillosis - pulm infiltrates and fever in neutropenic pt - get CXR.
Mucormcosis
Mold, non-septate branching hyphae >/=90 angle.
Ubiquitous, but usu immunocompromised or DM w DKA, neutropenic
Inhaled, but disseminates and angioinvasive –> tissue infarction/necrosis - penetrates cribriform plate and enters brain.
Presentations: invasive sinusitis, rhinocerebral abscess, pulm, renal, cutaneous, wounds
Tx: surgical debridement
Yeasts
Candida, cryptococcus, pneumococcus
Molds
Aspergillus, mucorales
Germ tube +
C. albicans
tx: azole
Yeast w large capsule
Cryptococcus
Chronic steroids + cough
Pneumocystis
Pulmonary sx + neutropenia
Aspergillus
acute angle!
DKA + facial ischemia
Murocmycosis
