Unusual manifestations in primary hypothyroidism.

Nineteen patients with overt hypothyroidism were examined for the prevalence of myocardial disfunction, respiratory disturbances, peripheral neuropathy, and visual failure due to pituitary enlargement. Prevalences of pericardial effusion and myocardial disfunction (decrease PEP/LVET) were 50% and 75%, respectively. The degree of decreased myocardial function did not parallel with the grade of pericardial effusion. Arterial blood analysis indicated a frequent incidence of hypoxia in hypothyroidism. The incidence of hypoxia was 69%. The hypoxia was improved by thyroxine replacement therapy. In 6 patients examined for the ventilatory control, all had the index for hypercapnic ventilatory drive lower than normal control. It was suggested that the hypoxia in hypothyroidism was caused by a depression of the respiratory center in the brain and by anemia. Sensory nerve conduction was diminished in 6 of 11 hypothyroid patients and motor conduction in 6 of 15 was studied. In distal segments of sensory nerves, the abnormality frequently appeared before clinical symptoms of polyneuropathy. Visual field defect was detected in 71% of patients suffering of primary hypothyroidism. The most common characteristic change was the defect in the central visual field. All cases of visual field defect were cured by thyroid hormone replacement therapy. Two cases with deteriorated visual failure who did not improve during physiological replacement, were successively treated with over dosage of thyroid hormone.