A family study of hereditary angioneurotic oedema.
Hereditary angioneurotic oedema is a rare condition inherited as an autosomal dominant and characterized by episodic circumscribed oedema of the skin, subcutaneous tissues, or mucous membranes. Life may be threatened when the pharynx or larynx are involved and oedema of the intestinal mucous membrane, presenting as colicky abdominal pain and vomiting, may lead to unnecessary surgical intervention. The condition is due to deficiency of the functional inhibitor of the activated first component of complement. Consumption of the inhibitor by activation of other plasma esterase systems permits spontaneous activation of the initial stages of the complement system and leads to the appearance of a kinin derived from the second component of complement which causes oedema by increasing vascular permeability.

Four patients in three generations of a family with hereditary angioneurotic oedema are presented with special reference to attacks of abdominal colic. The clinical and radiological appearances and serological changes are described before, during, and after treatment by transfusion of fresh-frozen plasma. It was confirmed that this, by replacing the inhibitor, is highly effective in terminating attacks without significant side-effects. It was also confirmed by a controlled trial that epsilon-aminocaproic acid acts prophylactically by reducing the frequency and severity of attacks of oedema.