Histamine, cortisol and organ changes in fatal anaphylactic shock in guinea-pigs.

Anaphylactic shock was produced in guinea-pigs by sensitizing them with oval albumin and challenging them with an intracardial dose (rapid shock) or intraperitoneal dose (slow shock) of the same protein 4 weeks later. The animals died within 5 min or 30 min, respectively. Blood for biochemical assays was taken by cardiac puncture and tissue samples were excised for histamine assay and histological studies. High concentrations of histamine (4-5 times the control values) were measured in the animals which died rapidly, but not in the others, whereas the histamine content of the stomach wall and lungs was decreased both in rapid and slow shock. Plasma cortisol was low in the rapid shock group. Plasma free fatty acids were high in both groups, but glucose only in the slow shock group. The lungs were distended, indicating bronchial obstruction. Occasional platelet agglutinations were seen in the lung veins. The most promising signs regarding the diagnosis of death from anaphylaxis were the high plasma histamine values and acute emphysema.