I know the buffalo hump will develop in cases in extreme conditions of the adrenal glands--Cushing's syndrome. Why does it develop in HIV/AIDS? Is it the side effect of medicine, or does the medicine effect the adrenal glands/cortisone which then causes the buffalo hump to grow. Or is it becuase the patient's stress may cause the cortisone imbalance which in turn causes the buffalo hump?

In a limited number of patients, it may well be some abnormally increased cortisol level. However, in HIV infection (and particularly with its treatment with certain drugs, such as the older protease inhibitors), there is some abnormality of how fat and subcutaneous tissue is laid down. The specific defect has not been conclusively identified, but it leads to accumulation of fat in the abdomen and back of the neck, and loss of subcutaneous tissue in the buttocks, arms, legs and face. The two changes (acumulation in some areas and loss in others) may even be completely separate processes. We now know what antiretroviral drugs to use to avoid this problem as much as possible, so hopefully it will happen less and less often as we move forward. Identifying the specific mechanism of the changes will also be helpful in designing more targeted treatments.