Gastrointestinal manifestations of HIV infection are common. Approximately 50 percent of AIDS patients will present with gastrointestinal complaints at some time during their illness. The most frequent presenting symptoms include odonophagia, abdominal pain, bleeding, and diarrhea. Organisms commonly associated with gastrointestinal infection in AIDS patients are shown in Table 139-4. Emergency department evaluation should focus on recognizing the severity of symptoms and obtaining appropriate initial diagnostic studies. Therapy should include volume and electrolyte repletion and initiation of antibiotic therapy when appropriate. Disposition should be based on the duration of symptoms, the clinical appearance of the patient, and the response to emergency department therapy.
Diarrhea is the most frequent gastrointestinal complaint and is estimated to occur in 50 to 90 percent of AIDS patients. It is caused by a wide variety of enteric pathogens that affect the general population as well as other, less virulent organisms that are more common in the immunocompromised population. Emergency department evaluation of patients with diarrhea should include microscopic examination of stool for leukocytes, ova, and parasites; acid-fast staining; and bacterial culture of stool. Common causes include bacterial organisms, such as Shigella, Salmonella, enteroadherent Escherichia coli, and Campylobacter; parasitic organisms, such as Giardia, Cryptosporidium, and Isospora belli; CMV; M. avium intracellulare; and antibiotic therapy.17
Clinical clues regarding the cause of diarrheal illnesses may be provided by the patient's history and confirmed by supplementary testing; however, results are usually not available during the emergency department visit. Bacterial pathogens generally follow a more acute and fulminant course, while parasitic infections are more frequently indolent. If bacterial infection is suspected, empiric treatment with ciprofloxacin, which covers the common bacterial pathogens, can be started. Cryptosporidium and Isospora infection are common parasitic causes and are associated with profuse watery diarrhea. Both can be identified by a modified acid-fast stain. Isospora belli is usually responsive to TMP-SMZ, but relapse is common. Cryptosporidiosis tends to be difficult to treat. In patients with end-stage disease, the most common pathogens are CMV and M. avium intracellulare; both diagnoses usually require biopsy. Prolonged antimicrobial therapy is indicated for treatment, and resistance and relapse are frequent for both entities. About 15 percent of patients with late-stage AIDS suffer from severe, high-volume, watery diarrhea with no pathogen identified even after thorough investigation. The presumed diagnosis is AIDS-related enteropathy. Patients often require admission for correction of electrolyte abnormalities and rehydration. Octreotide, the somatostatin analogue, may be helpful in some cases.
Emergency department management should be directed toward repletion of fluid and electrolytes. Patients who are nontoxic appearing and can tolerate liquids can be referred for outpatient follow-up of test results. Patients with severe diarrhea who do not require antibiotics may benefit from symptomatic therapy, such as attapulgite (Kaopectate), psyllium (Metamucil) and, if necessary, diphenoxylate hydrochloride with atropine (Lomotil).
Oral lesions are common in HIV-infected patients and frequently contribute to malnutrition. Oral candidiasis or thrush affects more than 80 percent of AIDS patients. The tongue and buccal mucosa are commonly involved, and the plaques characteristically can be easily scraped from an erythematous base. Differentiation from hairy leukoplakia (usually manifested as adherent, white, thickened lesions on the lateral tongue borders) may be challenging for the inexperienced, but microscopic examination on potassium hydroxide smear confirms the diagnosis. The development of oral candidiasis is a poor prognostic sign and is predictive of progression to AIDS. Most oral lesions can be managed symptomatically on an outpatient basis. Clotrimazole or nystatin suspension or troches (five times daily) are the preferred treatment. Refractory or recurrent disease can be managed with oral fluconazole. Amphotericin B is reserved for severe cases.
Other causes of painful oral and perioral lesions include oral hairy leukoplakia, herpes simplex virus, and Kaposi's sarcoma. Herpes simplex can usually be recognized by typical vesicular lesions, with diagnosis confirmed by identifying multinucleated giant cells from scrapings or by culture. Both herpes simplex and hairy leukoplakia are responsive to oral acyclovir. Oral Kaposi's sarcoma appears as a nontender, well-circumscribed, slightly raised violaceous lesion. Diagnosis requires biopsy; topical treatments may be palliative.
Esophageal involvement may occur with Candida, herpes simplex, and CMV. Complaints of odonophagia or dysphagia are usually indicative of esophagitis and may be extremely debilitating. Disease typically occurs in patients who have oral thrush and CD4 counts of less than 100 cells/pL. Treatment of esophagitis in the emergency department is usually presumptive. Endoscopy, histologic staining, culture, and biopsy are reserved for patients who fail to respond or have atypical presentations. Presumptive treatment for Candida, which accounts for 50 to 70 percent of cases, is with oral fluconazole (200 to 400 mg qd for 2 to 3 weeks) or oral ketoconazole (100 to 200 mg qd for 2 to 3 weeks). Relapses are common, and intravenous amphotericin B may occasionally be required. Treatment failures endoscopically discovered to be caused by CMV and herpes simplex are treated with acyclovir and gancyclovir, respectively.
Hepatomegaly occurs in approximately 50 percent of AIDS patients. Elevation of alkaline phosphatase levels is frequently seen. Jaundice is rare. Coinfection with hepatitis B and hepatitis C is common, especially among injected drug users. Opportunistic infection with CMV, Cryptosporidium, M. avium intracellulare, and MTB may also cause signs of hepatitis.
Anorectal disease is common in AIDS patients. Proctitis is characterized by painful defecation, rectal discharge, and tenesmus. Common causative organisms include Neisseria gonorrhoeae, Chlamydia trachomatis, syphilis, and herpes simplex. Proctocolitis includes the same symptoms in the presence of diarrhea, and multiple bacterial organisms may be responsible (most commonly Shigella, Campylobacter, and Entamoeba histolytica). Diagnostic evaluation should include anoscopy, with microscopic examination, Gram stain, and culture of pus and/or stool.
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