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Shigella (Shigella sp.) Enteritis

Clinical Presentation:  Acute onset of bloody diarrhea/mucus..

Diagnostic Considerations:  Diagnosis by demonstrating organism in stool specimens. Shigella­ ulcers in colon are linear, serpiginous, and rarely lead to perforation. . More common in gay men..

Therapeutic Considerations:  Shigella dysentery is more acute/fulminating than amebic dysentery.. Shigella has no carrier state, unlike Entamoeba.. Shigella infections acquired outside of United States have high rates of TMP–SMX resistance.. Therapy is indicated to shorten the duration of illness and to prevent spread of infection.. Shigella has no carrier state..

Prognosis:  Good if treated early. . Severity of illness related to Shigella species: S. . dysenteriae (most severe) > S.. flexneri > S.. boydii/S.. sonnei (mildest)..

Clinical Presentation:  White, cheesy, vaginal discharge or vulvar rash ± itching/pain.. Local ­infection not a sign of disseminated disease..

Diagnostic Considerations:  Local infection.. Not a manifestation of disseminated disease..

Pitfalls:  Women with advanced AIDS receiving fluconazole may develop fluconazole-resistant ­Candida.. Therapeutic Considerations:  For recurrence, consider maintenance with fluconazole 100–200 mg (PO) weekly..

Prognosis:  Good response to therapy.. Relapses are common..

Coccidioidomycosis (C. immitis) Infection

*Therapy for meningeal infection should be lifelong with fluconazole 400–800 mg q24h. . There are ­insufficient data to recommend discontinuation of chronic maintenance therapy in other settings..

Clinical Presentation:  Typically a complication of advanced HIV infection (CD4 cell count < 200/mm3).. Most patients present with disseminated disease, which can manifest as fever, diffuse pulmonary­ infiltrates, adenopathy, skin lesions (multiple forms – verrucous, cold abscesses, ulcers, nodules), and/or bone lesions.. Approximately 10% will have spread to the CNS in the form of ­meningitis (fever, headache, altered mental status)..

Diagnostic Considerations:  Consider the diagnosis in any patient with advanced HIV-related immunosuppression who has been in a C.. immitis endemic area (Southwestern US, northern Mexico) and presents with a systemic febrile syndrome.. Diagnosis can be made by culture of the organism, ­visualization of characteristic spherules on histopathology, or a positive complement-fixation antibody (≥ 1:16).. In meningeal cases, CSF profile shows low glucose, high protein, and lymphocytic pleocytosis..

Pitfalls:  Antibody titers often negative on presentation.. CSF profile of meningitis can be similar to TB.. Prognosis:  Related to extent of infection and degree of immunosuppression.. Clinical response tends to be slow, especially with a high disease burden and advanced HIV disease.. Meningeal disease is treated life-long regardless of CD4 recovery..

Extrapulmonary Tuberculosis

Clinical Presentation:  Multiple presentations possible (e. .g. ., lymphadenitis, osteomyelitis, meningitis, hepatitis).. Dissemination is more common in patients with low CD4 cell counts (< 100/mm3)..

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Diagnostic Considerations:  Diagnosis by isolator blood cultures or tissue biopsy..

Pitfalls:  Patients with disseminated disease frequently have pulmonary disease, which has implications for infection control..

Therapeutic Considerations:  Response to therapy may be slower than in normal hosts.. Prognosis:  Usually responsive to therapy..

Herpes Simplex Virus (HSV) Disease

Herpes Simplex (genital/oral)

Clinical Presentation:   Painful, grouped vesicles on an erythematous base that rupture, crust, and heal within 2 weeks.. Lesions may be chronic, severe, ulcerative with advanced ­immunosuppression.. Diagnostic Considerations:  Diagnosis by viral culture of swab from lesion base/roof of blister; alternative diagnostic techniques include Tzanck prep or immunofluorescence staining..

(e..g.., cervical adenitis), or severe disease with fever, wasting ± diarrhea/meningitis/GI ulcerations.. Diagnostic Considerations:  Diagnosis by urine/serum histoplasmosis antigen, sometimes by culture of bone marrow/liver or isolator blood cultures.. May occur in patients months to years after having lived/ moved from an endemic area..

Pitfalls:  Relapse is common after discontinuation of therapy.. Cultures may take 7–21 days to turn positive..

Therapeutic Considerations:  Initial therapy depends on severity of illness on presentation.. Extremely sick patients should be started on amphotericin B deoxycholate, with duration of IV therapy dependent on response to treatment.. Mildly ill patients can be started on itraconazole.. All patients require chronic suppressive therapy, with possible discontinuation for immune reconstitution with CD4 counts > 100/ mm3 for at least 6 months.. HIV patients with CD4 > 500/mm3 and acute pulmonary histoplasmosis might not require therapy, but a short course of itraconazole (4–8 weeks) is reasonable to prevent systemic spread..

Prognosis:  Usually responds to treatment, except in fulminant cases..

Mycobacterium avium-intracellulare (MAI)

Clinical Presentation:  Typically presents as a febrile wasting illness in advanced HIV disease (CD4 < 50/mm3). . Focal invasive disease is possible, especially in patients with advanced immunosuppression after starting antiretroviral therapy.. Focal disease likely reflects restoration of pathogen-specific immune response to subclinical infection (“immune reconstitution inflammatory syndrome” [IRIS]), and typically manifests as lymphadenitis (mesenteric, cervical, thoracic) or rarely disease in the spine mimicking Pott’s disease.. Immune reconstitution syndrome usually occurs within weeks to months after starting antiretroviral therapy for the first time, but may occur a year or more later..

Diagnostic Considerations:  Diagnosis by isolation of organism from a normally sterile body site (blood, lymph node, bone marrow, liver biopsy).. Lysis centrifugation (DuPont Isolator) is the preferred blood culture method.. Anemia/↑ alkaline phosphatase are occasionally seen..

Pitfalls:  Isolator blood cultures may be negative, especially in immune reconstitution inflammatory syndrome initially..

Therapeutic Considerations:  Some studies suggest benefit for addition of rifabutin 300 mg (PO) q24h, others do not. . Rifabutin may require dosage adjustment with NNRTI’s and PI’s. . For concurrent use with nelfinavir, indinavir, or amprenavir, decrease rifabutin to 150 mg (PO) q24h. . For concurrent use with ritonavir, decrease rifabutin to 150 mg (PO) 2–3x/week. . For concurrent use with efavirenz, increase rifabutin to 450–600 mg (PO) q24h. . The dose of PI’s or NNRTI’s may need to be increased by 20–25%. . Monitor carefully for rifabutin drug toxicity (arthralgias, uveitis, leukopenia). . Treat IRIS initially with NSAIDs; if symptoms persist, systemic corticosteroids (prednisone 20–40 mg daily) for 4–8 weeks can be used.. Some patients will require a more prolonged course of corticosteroids with a slow taper over months.. Azithromycin is often better tolerated than clarithromycin and has fewer drug-drug interactions.. Optimal long-term management is unknown, though most studies suggest that treatment can be discontinued in asymptomatic patients with > 12 months of therapy and CD4 > 100/ mm3 for > 6 months..

Prognosis:  Depends on immune reconstitution in response to antiretroviral therapy.. Adverse prognostic factors include high-grade bacteremia or severe wasting..

Varicella Zoster Virus (VZV)

Clinical Presentation:  Primary varicella (chickenpox) presents as clear vesicles on an erythematous base that heal with crusting and sometimes scarring.. Zoster usually presents as painful tense vesicles on an erythematous base in a dermatomal distribution.. In patients with HIV, primary varicella is more severe/prolonged, and zoster is more likely to involve multiple dermatomes/disseminate.. VZV can rarely cause acute retinal necrosis, which requires close consultation with ophthalmology..

Diagnostic Considerations:  Diagnosis is usually clinical.. In atypical cases, immunofluorescence can be used to distinguish herpes zoster from herpes simplex..

Pitfalls:  Extend treatment beyond 7–10 days if new vesicles are still forming after initial treatment period.. Corticosteroids for dermatomal zoster are not recommended in HIV-positive patients.. Therapeutic Considerations:  IV therapy is generally indicated for severe disease/cranial nerve zoster.. Prognosis:  Usually responds slowly to treatment..