Unusually high serum levels of lactate dehydrogenase without perivalvular leakage following double valve replacement: predictor of tetany attack after thyroidectomy.

A 57-year-old woman who complained of exertional dyspnea was diagnosed as having severe aortic valve stenosis and mitral valve regurgitation. The patient underwent double valve replacement with a mechanical prosthesis. Postoperative laboratory data showed unusually high serum lactate dehydrogenase (LDH) levels, even though no perivalvular leakage was detected by echocardiography. Tetany occurred suddenly owing to hypoparathyroidism, which seemed to be a late complication after thyroidectomy. After calcium administration, the symptoms dramatically diminished, as did the serum LDH levels. Hypoparathyroidism should be doubted if serum LDH levels increase higher than the normal range following valve replacement without obvious perivalvular leakage.

Hypoparathyroidism in a patient with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency caused by the G1528C mutation.

Mitochondrial trifunctional protein (MTP), an enzyme complex participating in fatty acid beta-oxidation, is the potential site of two documented defects: long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) and MTP deficiencies. LCHAD deficiency usually manifests as hypoglycemia, with hepatopathy, hypotonia, cardiomyopathy, and retinopathy. Hypoparathyroidism has been detected in a patient with MTP deficiency. We now report on a patient with LCHAD deficiency and hypoparathyroidism, evidenced by hypocalcemia, hyperphosphatemia, and a low level of parathyroid hormone, in whom the parathyroid glands could not be located after death.

[Serum striated muscle enzymes in autoimmune hypoparathyroidism].

Elevated serum levels of creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) are generally present in cases of muscle or heart disease, though there are some exceptions. We treated a 56-year-old man diagnosed as suffering from primary idiopathic hypoparathyroidism (PIHP). The neurologic examination was normal, but serum levels of CPK and LDH, and especially isoenzymes of striated muscle, were elevated. Elevated levels of these enzymes in PIHP are rare. In this case they most probably leaked from muscle into the blood circulation after changes in the muscle cell membrane due to hypocalcemia.

Spontaneous hypoparathyroidism: clinical, biochemical and radiological features.

The clinical, biochemical and radiological features of spontaneously occurring hypoparathyroidism in 13 patients (mean age 9 years, range 4 months to 20 years) are highlighted. Nine patients presented with a history of generalised seizures and 2 were in acute hypocalcemic crisis at the time of admission. Ocular involvement (corneal opacities, cataract) was present in 3 patients and vitiligo in 1 patient. The serum calcium level was low (mean 5.46 mg/dl, range 5.0-7.2) and serum phosphorus level was high (mean 8.49 mg/dl, range 6-14 mg/dl) in all the patients. Six patients had elevated serum alkaline phosphatase (greater than 20 KAU). Radiological examination revealed osteopenia in 3 patients. Nine patients underwent a head CT scan; 5 had evidence of basal ganglia calcification. The findings of elevated serum alkaline phosphatase and osteopenia are at variance with existing literature and may possibly reflect pre-existing vitamin D deficiency.

Calcium-ATPase activity in erythrocyte ghosts from patients with familial benign hypercalcaemia.

It has been suggested that the parathyroid glands and the kidneys are insensitive to the high extracellular calcium levels found in familial benign hypercalcaemia (FBH) (familial hypocalciuric hypercalcaemia) and that there may be a general disorder of the plasma membrane 'calcium pump'. We have found that the activity of the calcium-stimulated, magnesium-dependent ATPase of erythrocyte ghost membranes from patients with FBH was significantly higher (p less than 0.01) than that from normal subjects. Values in FBH, as a group, were higher than those in primary hyperparathyroidism, but the difference was not significant. We suggest that the membrane abnormality in FBH could be a disorder of the regulation of the calcium pump.

Hypoparathyroidism and elevated muscle enzymes.

We studied a patient with hypocalcemia and increased serum activity of sarcoplasmic enzymes. Idiopathic hypoparathyroidism was established by history, low serum parathyroid hormone content, and marked responsiveness of urinary cyclic AMP and phosphate to parathyroid hormone. Muscle-associated isoenzymes of creatine phosphokinase and lactic dehydrogenase were increased, but there was no concomitant muscle weakness. Muscle biopsy was normal by morphologic and histochemical examination. The patient was treated with calcium and vitamin D. As the calcium rose, there were corresponding decreases in the serum activities of creatine phosphokinase and lactic dehydrogenase, with correlation coefficients of -0.88 and -0.64, respectively (p less than 0.01).

Hypocalcaemic myopathy with paranoid psychosis.

A description is given of a patient with idiopathic hypoparathyroidism and a paranoid psychosis. Changes in muscle, electromyograms, and blood enzyme levels were related to hypocalcaemia. Reference is made to the elevations of these enzyme levels found in other cases of psychosis.