Enlargement of the carotid bodies in cirrhosis of the liver

The carotid bodies were dissected out at necropsy and weighed in seven subjects with cirrhosis of the liver and in seven control subjects of comparable age free of liver disease. The mean combined carotid body weight of the control group was 17mg but in the cirrhotic patients it was 35 mg, a statistically significant difference (P < 0.005). Differential counts of the various types of glomic cell (progenitor, dark and light variants of chief cells and sustentacular cells) were carried out. The enlargement of the carotid bodies in the subjects with cirrhosis was associated with increased numbers of the dark variant of chief cell. The mean number of dark cells per unit area in the control group was 361 cells/mm2 but in the cirrhosis group it was 1024 cells/mm2, a statistically significant difference (P < 0.005). It is postulated that the prominence of dark cells may be associated with secretion of a natriuretic peptide in response to the hyperaldosteronism and sodium retention of cirrhosis of the liver. Alternatively, it may be a response to hypoxaemia resulting from porta-pulmonary shunts.