Elsevier

The Lancet

Volume 351, Issue 9106, 21 March 1998, Pages 867-870
The Lancet

Early Report
“Buffalo hump” in men with HIV-1 infection

https://doi.org/10.1016/S0140-6736(97)11443-XGet rights and content

Summary

Background

Enlargement of the dorsocervical fat pad (“buffalo hump”) has been reported in numerous HIV-1-infected patients. Some investigators have speculated that this finding is associated with protease-inhibitor treatment.

Methods

Between June, 1995, and October, 1997, we studied eight HIV-1-infected men who had developed a buffalo hump while otherwise stable on antiretroviral therapy. Measurement of 24 h urinary free cortisol excretion and an overnight low-dose dexamethasone suppression test were done to screen for Cushing's syndrome. In one patient, plasma cortisol concentrations were measured every 4 h for 24 h to assess the circadian rhythm of cortisol. Results of total and regional body-composition analysis by dual-energy X-ray absorptiometry, and glucose, cholesterol, triglyceride, and cortisol concentrations were compared with those obtained in a control population of 15 HIV-1-positive men whose age, body-mass index (BMI), and CD4-lymphocyte count were within the range of values in the eight study patients.

Findings

The eight patients with a buffalo hump were clinically stable on various antiretroviral regimens, four of which included a protease inhibitor. No other signs of Cushing's syndrome were observed, and plasma cortisol values did not differ significantly from those of controls. 24 h urinary free cortisol excretion was normal in seven patients and slightly raised in one (248 nmoles). In this patient, a repeat 24 h urinary free cortisol was 175 nmoles and plasma cortisol concentrations over 24 h showed a normal circadian pattern (nadir 83 nmol/L at 2400 h). All eight patients had normal suppression of cortisol values after dexamethasone 1 mg (plasma cortisol less than 83 nmol/L). When compared with HIV-1-positive controls, men with a buffalo hump had a significantly greater proportion of fat in the trunk region, suggesting central fat accumulation. Triglyceride but not cholesterol values were higher in the patients than in controls but this difference was not significant. Fasting glucose values did not differ significantly.

Interpretation

The development of a buffalo hump cannot be attributed to hypercortisolism in these eight men. Furthermore, its occurrence is not unique to patients on protease inhibitors. Although the mechanism for dorsocervical fat accumulation is unclear, we speculate that regional abnormalities in lipogenesis and lipolysis occur, possibly influenced by the hormonal and metabolic changes seen with HIV-1 infection and its treatment.

Introduction

The accumulation of adipose tissue in the dorsocervical region, commonly referred to as “buffalo hump, is a typical finding in patients with glucocorticoid excess. Although benign, this disorder can lead to substantial disfigurement and so compromise quality of life. Recently, anecdotal reports of HIV-1-infected patients who developed a buffalo hump have appeared on the Internet (“Crix list”: http://crix.pinkpage.com/; accessed on March 9, 1998) and in the medical literature.1, 2 The observation that enlargement of the dorsocervical fat pad occurred after initiation of combination antiretroviral therapy that included a protease inhibitor has led to the suggestion that the enlargement could be a consequence of protease-inhibitor therapy.

We report the results of studies done in eight HIV-1-positive men referred for investigation of a buffalo hump, four of whom were on triple antiretroviral regimens that included a protease inhibitor. Measurement of urinary free cortisol excretion and an overnight low-dose dexamethasone suppression test were done to screen for Cushing's syndrome. In addition, total and regional body-composition analysis and measurements of lipids, glucose, and cortisol in these men were compared with those obtained in a control population of HIV-1-infected men without buffalo hump.

Section snippets

Patients

We studied eight consecutive HIV-1-positive men referred to the Division of Endocrinology, San Francisco General Hospital, for investigation of dorsocervical-fat-pad enlargement between June, 1995, and October, 1997. 15 HIV-1-positive men without dorsocervical-fat-pad enlargement were selected as controls during the same period from a natural history cohort study conducted by our group. The controls were selected to be within the range of the age, body-mass index (BMI), and CD4-lymphocyte count

Results

The clinical characteristics of the eight men with buffalo hump are shown in table 1. The mean time from diagnosis of HIV-1 infection was 9·6 (SD 3·7; range 5–15) years. All eight patients were on stable nucleoside-analogue therapy; four of these (patients 5–8) had started treatment with a protease inhibitor 2–18 months (median 7·5) before development of a buffalo hump. Patients 1–6 reported stable bodyweights. Patient 7 reported 7 kg weight loss due to colitis 4 months before the development

Discussion

We have excluded Cushing's syndrome as the cause of dorsocervical-fat-pad enlargement in the eight HIV-1-positive men reported here. All patients had a normal response to a low dose of dexamethasone, with suppression of plasma cortisol values to less than 83 nmol/L. These findings exclude Cushing's syndrome with more than 95% certainty.6, 7, 8 24 h urinary free cortisol excretion, which is higher than normal in more than 90% of patients with Cushing's syndrome,9, 10, 11 was within the normal

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