atrial-natriuretic-factor and Myxedema

The average plasma AVP in 12 cases of patients with overt myxedema was higher than that of normal controls (n = 5) before water loading, though there was no significant difference (P greater than 0.05). The plasma ANP levels were increased (P less than 0.05). After water loading the average plasma osmolality level of patients was lower, and the mean plasma AVP concentration of patients was not suppressed after loading. A disturbance in water clearance was demonstrated. The mean levels of plasma ANP and aldosterone were not markedly changed in patients before and after loading. These observations coincide with the changes of SIADH. Most of the above blood parameters were improved along with thyroid function in 9 patients who were restored to normal after replacement with desiccated thyroid.

Topics: Adolescent; Adult; Aldosterone; Arginine Vasopressin; Atrial Natriuretic Factor; Female; Humans; Inappropriate ADH Syndrome; Male; Middle Aged; Myxedema; Water-Electrolyte Balance

We monitored the plasma and urine osmolalities, fractional excretion of sodium, fractional excretion of chloride, plasma levels of antidiuretic hormone (ADH, AVP), aldosterone and atrial natriuretic peptide (ANP) before and after acute water ingestion in 12 patients with overt hypothyroidism. The ability of the patients to dilute and concentrate urine was found impaired and the ability of excretion of water load decreased and delayed. Acute water load test was proved to be effective in evaluating the urinary excreting function for the patients. We hypothesize that inappropriate secretion of anti-diuretic hormone and elevated plasma ANP may be homeostatic factors for abnormal urinary excretion in patients with hypothyroidism.

Topics: Adolescent; Adult; Aldosterone; Atrial Natriuretic Factor; Body Water; Female; Humans; Male; Middle Aged; Myxedema; Natriuresis; Osmolar Concentration; Vasopressins; Water-Electrolyte Balance

A 40-year old female was admitted with complaints of general fatigue and dyspnoea brought on by effort. There were edema on the face, a diffuse and slightly hard goiter on the neck and non-pitting edema in the lower legs. Laboratory findings showed low levels of serum T3 (0.37 ng/ml) and T4 (2.0 micrograms/dl), a very high level of serum TSH (549.8 microU/l), positive thyroid test (x 400) and positive microsome test (x 102,400). The chest roentgenogram showed an enlargement (CTR 62%) of the cardiac silhouette in the shape an ice bag, and the electrocardiogram revealed low QRS voltage with T-wave flattening in all leads. Remarkable pericardial effusion was shown on the two-dimensional echocardiogram. Judging from the indications of hypothyroidism, positive antithyroid antibody and pericardial effusion. This patient was diagnosed as having myxedema heart due to chronic thyroiditis. The levels of plasma alpha-hANP did not elevate so much as the levels in normal controls after right atrial (RA) pacing, although mean right atrial pressure was higher than in normal controls after RA pacing. The levels of plasma alpha-hANP after RA pacing in euthyroid state were higher than those in hypothyroid state. The levels of plasma alpha-hANP after RA pacing became higher after the administration of ATP or db-cAMP both in euthyroid and hypothyroid states. These results indicate that the impaired alpha-hANP secretion in myxedema heart is improved by the administration of thyroxine, ATP or db-cAMP.

Topics: Adenosine Triphosphate; Adult; Atrial Natriuretic Factor; Bucladesine; Chronic Disease; Drug Therapy, Combination; Female; Heart Diseases; Humans; Myxedema; Thyroiditis; Thyroxine