Prevalence of abnormal adrenocortical function in human immunodeficiency virus infection by low-dose cosyntropin test.

Recent evidence suggests that 10 microg cosyntropin test has higher sensitivity for detecting hypothalamus-hypophysis-adrenal axis (HHA-A) dysfunction. Our objective was to determine prevalence of glucocorticoid insufficiency with the 10 microg cosyntropin test and the level of the HHA-A defect. One hundred and four HIV-infected patients underwent the 10 microg cosyntropin test. In abnormal and borderline respondents, insulin-induced hypoglycaemia test and human corticotropin releasing hormone test were used to confirm and localize the level of the HHA-A defect. Thirty-two patients with HIV infection and 72 with AIDS were identified. Prevalence of glucocorticoid insufficiency by the 10 microg cosyntropin test was 21.2%. By clinical categories, the frequency in AIDS and HIV infection patients was 26.4% and 9.4%, respectively. Confirmed glucocorticoid insufficiency by insulin-induced hypoglycaemia test was found in 16 out of 19 cases. Twelve cases had primary glucocorticoid insufficiency, 7 had secondary glucocorticoid insufficiency and 3 were false positive. In conclusion, adrenocortical dysfunction occurs in approximately 20% of the cases with HIV disease. Clinical findings commonly occurring in HIV disease as well as adrenocortical insufficiency are not reliable indicators for performing adrenocortical laboratory assessment. Our results suggest screening all AIDS patients with the 10 microg cosyntropin test.

Chronic lymph flow and transcapillary fluid flux during angiotensin II hypertension.

The roles of the transvascular fluid flux and lymph flow in the distribution of extracellular fluid volume during angiotensin II (ANG II) hypertension were evaluated in 11 conscious dogs. Similarly, the factors regulating the distribution of plasma protein across the microvasculature were assessed. By the second day of ANG II infusion, the thoracic duct lymph flow had increased 58% above control, transcapillary fluid flux had increased 45%, and plasma volume, sulfate space, and interstitial fluid volume remained close to control. In addition, the thoracic duct lymph protein transport had increased 34%, and the accompanying increase in transcapillary protein flux prevented any change in plasma protein mass. Also, at this time, the lymph flow and protein transport from subcutaneous tissue in the hind limb were not increased, and the permeability-surface area product of this region decreased 40%. The origin of the increased thoracic duct lymph flow on day 2 probably was from the splanchnic bed. In conclusion, the increased lymph flow during ANG II hypertension compensated for the increase in transcapillary fluid flux, thus preventing edema formation.

Chronic transvascular fluid flux and lymph flow during volume-loading hypertension.

The chronic roles of the transcapillary fluid flux and lymph flow in the distribution of extracellular fluid volume during volume-loading hypertension were investigated in five conscious dogs. Similarly, the distribution of plasma proteins across the microvasculature was evaluated. During the early phases of volume-loading hypertension the fluid balance was positive, which caused the extracellular fluid volume and the plasma volume to increase 25 and 15%, respectively. The thoracic duct lymph flow more than doubled, but the increase in transcapillary fluid flux was even greater. Therefore the interstitial fluid volume increased 30%. This fluid shift from the vasculature into the interstitium probably prevented an even greater rise in arterial pressure. In addition, the transcapillary protein flux more than doubled, but the accompanying increase in lymph protein transport prevented any change in plasma protein mass. During the latter part of the saline-infusion period, the lymph flow declined toward its control, which caused a net transfer of fluid into the interstitium. In conclusion, the transcapillary fluid flux and lymph flow play significant roles in extracellular fluid volume distribution.