Page 224 - AIDSBK23C

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GENITOURINARY PATHOLOGY IN AIDS

The genitourinary system is occasionally affected by infectious agents seen in AIDS
(Table 5). When either malignant lymphoma, cryptococcosis, or Mycobacterium tuberculosis is
present with AIDS at autopsy, the kidney is involved about one fourth of the time. Despite the
fact that HIV infection is most frequently spread by sexual means, lesions of the male and female
genital tract with HIV infection are not frequent, and no specific direct effect of HIV has been
documented at these sites. Clinical life-threatening urologic problems are rare in AIDS, but
patients can have urinary tract and prostatic infections more frequently than in
immunocompetent persons.[919]
Urinalysis may reveal proteinuria and microalbuminuria associated with HIV infection.
Approximately a third of HIV-infected persons may have either finding. Risks include African-
American race, higher HIV-1 RNA level, ad lower CD4 lymphocyte count. Microalbuminuria is
associated with development of insulin resistance and increased risk for cardiovascular and renal
diseases.[920]
Hematuria is not common from opportunistic infections or neoplasms because such
lesions are neither numerous nor extensive in the genitourinary tract (Table 5). Cytomegalovirus
inclusions are not commonly observed in urine specimens. Decreased renal function may be
associated with nephritis from drug therapies (amphotericin B, pentamidine, sulfamethoxazole).
Acute renal failure with tubular necrosis may occur in the terminal course with AIDS.
Serum electrolyte abnormalities are relatively common with AIDS. Hypokalemia can be
seen with chronic diarrhea and vomiting, while hyperkalemia is associated with metabolic
acidosis and impaired renal function. Hyponatremia, which is present in up to a third of
hospitalized patients with HIV-infection, can occur with diarrhea and with volume depletion, as
well as with a syndrome of inappropriate antidiuretic hormone secretion (SIADH) from
respiratory or CNS infections. Hyponatremia is a poor prognostic sign.[921]
A number of pharmacologic agents used to treat opportunistic infections seen in AIDS
can lead to renal failure as evidenced clinically by elevated blood urea nitrogen (BUN) and
creatinine measurements. The drugs foscarnet, didanosine, and pentamidine have been
implicated in cases of hypocalcemia, while foscarnet may also predispose to hypercalcemia.
Hyperuricemia can occur with didanosine therapy.[264,922]
Acute tubular necrosis (ATN) can occur from a variety of causes. Nephrotoxic ATN has
been reported with several pharmacologic agents for opportunistic infections, including
amphotericin B, pentamidine, and foscarnet. The antiretroviral agents adefovir, tenofovir,
cidofovir and ritonavir can also produce ATN.[257,921]
Protease inhibitors have been implicated in production of crystal-induced acute renal
failure and nephrolithiasis. Indinavir has been associated with nephrolithiasis in 5 to 25% of
patients. Crystallization occurs from inadequate hydration of patients taking this medication.
Other drugs with this side effect include sulfadiazine, acyclovir, and foscarnet. This effect can
be potentiated with lysis syndrome and high uric acid levels in patients treated for malignant
lymphomas. Urinary tract calculi can occur with sulfadiazine and indinavir therapy.[921,923]
Urinary tract infection (UTI) with HIV infection is most likely to occur when the CD4
count drops below 500/microliter. The most common bacterial pathogens include Escherichia
coli, Enterobacter, Pseudomonas aeruginosa, Proteus spp, Klebsiella, Acinetobacter,
Staphylococcus aureus, group D Streptococcus, and Serratia. UTI with Salmonella organisms