Pain syndromes and etiologies in ambulatory AIDS patients.

Ambulatory AIDS patients participating in a quality of life study were recruited for an assessment of pain syndromes. Of 274 patients with pain, 151 (55%) consented to the assessment which included a clinical interview, neurologic examination, and review of medical records. The number, type, and etiology of pains were evaluated in terms of risk factors, age, sex, CD4+ lymphocyte count, and performance status. The average number of pains per patient was 2.7 (range, 1-7), yielding a total of 405 pains. The most common pain diagnoses were headache (46% of patients; 17% of all pains), joint pain (31% of patients; 12% of pains), pain due to polyneuropathy (28% of patients; 10% of pains), and muscle pain (27% of patients; 12% of pains). Pathophysiology was inferred for all pain syndromes (except for headache), 45% of pain syndromes were somatic in nature, 15% were visceral, 19% were neuropathic, and 4% were unknown, psychogenic, or idiopathic; 17% of pains were classified as headache, hence pathophysiology could not be determined. Pain resulted from diverse etiologies, including the direct effects of HIV/AIDS-related conditions (30%) pre-existing unrelated conditions (24%), and therapies for HIV/AIDS and related conditions (4%). The latter category, pain related to HIV therapies, occurred in 11% of patients. In 37% of the pains, the etiology could not be determined from the information available. In univariate analyses, lower CD4+ cell counts were significantly associated with polyneuropathy (P < 0.05) and headache (P < 0.05), and female gender was significantly associated with the presence of headache (P < 0.05) and radiculopathy (P < 0.001). These data confirm the diversity of pain syndromes in AIDS patients, clarify the prevalence of common pain types, and suggest associations between specific patient characteristics and pain syndromes. The large proportion of patients who could not be given a diagnosis underscores the need for a careful diagnostic evaluation of pain in this population.