Calcium Metabolism in Bone Disease: Effects of Treatment with Microcrystalline Calcium Hydroxy Apatite Compound and Dihydrotachysterol1

Microcrystalline calcium hydroxyapatite compound (MCHC) was given orally together with small doses of dihydrotachysterol (DHT) to a number of patients with osteogenesis imperfecta (OI). Serial calcium and phosphate balances in three patients representing wide variations in severity of OI are presented over periods from eight months to two years. The combination of MCHC and DHT resulted in an immediate positive calcium balance which was maintained throughout the period of assessment in 2 cases. However, no radiological improvement could be demonstrated. Substituting calcium gluconate for MCHC resulted in a reduction of positive balance. No adverse effects were noted. The reasons why MCHC with DHT should result in increased calcium retention are discussed. This combination of MCHC and DHT could be of benefit in many common situations of bone demineralization, such as osteoporosis.

The D Vitamins and Dihydrotachysterol in Metabolic Diseases

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Possible prevention and treatment of steroid-induced osteoporosis

Patients with steroid-induced, juvenile and senile osteoporosis were studied using balance techniques. The changes in calciun and phosphorus balance associated with glucocorticoid therapy were corrected with vitamin D and bendrofluazide given in combination. No hypercalcaemia occurred in osteoporotic patients who continued to receive glucocorticoids. Calcium and phosphorus balance was also improved in the osteoporotic subjects not receiving steroids, but these patients became hypercalcaemic during treatment. It is suggested that vitamin D, bendrofluazide and steroids antagonize the actions of one another on the renal tubule, gut and bone and in this way prevent the increased calciuria which occurs with glucocorticoid therapy. Since the increased calciuria and negative calcium balance induced by glucocorticoids is considered to be the result of excessive bone resorption, an adequate dose of bendrofluazide and vitamin D in combination might prevent the development of, or even reverse, steroid-induced osteoporosis.

Osteoporosis in childhood

Osteoporosis is defined as 'too little normal bone', the disorder being rarer in children than adults. The varied forms in childhood can be classified as those secondary to some other disease and primary forms of the disorder which include the genetically determined osteogenesis imperfecta types and idiopathic forms of osteoporosis. A plea is made for greater clinical application in attempting to discriminate differing forms of these primary disorders. Osteogenesis imperfecta it is argued is a heterogeneous condition with the evidence favouring both dominantly and recessively transmitted forms in different kindreds. Another possible osteogenesis imperfecta variant is characterized by dwarfing, scoliosis and peculiar cystic lesions of the proximal humeri. Idiopathic juvenile osteoporosis is a term reserved for the acute osteoporosis beginning in the immediate prepubertal years and may differ in its cause from idiopathic osteoporosis beginning rather earlier in childhood. It is emphasized that immobilization osteoporosis is of very great importance and may become superimposed upon other osseous dysplasias. A complete understanding of these conditions will be helped by elucidation of the basic underlying defects in collagen and other constituents of bone matrix.

Hypophosphataemic osteomalacia in fibrous dysplasia

We describe three patients with fibrous dysplasia of bone in whom there was evidence of hypophosphataemic osteomalacia or rickets. Two of the patients had polyostotic fibrous dysplasia and osteomalacia. The third was a child with fibrous dysplasia of the facial and cranial bones and rickets. In all cases the manifestations of osteomalacia or rickets were controlled with large doses of vitamin D. In the child the rickets and hypophosphataemia ceased when most of the bone affected by fibrous dysplasia was surgically resected. Previously reported cases of the association between fibrous dysplasia and hypophosphataemic osteomalacia are reviewed. We suggest that these cases are analogous to the syndrome of 'tumour rickets' where hypophosphataemia appears to be due to the presence of a mesenchymal tumour and regresses when the tumour is removed.

Medullary carcinoma of thyroid gland in a girl aged 10 years

A healthy girl of 10 years presented with lumps on her tongue, shown on biopsy to be neuromas. She had had operations to her feet for pes cavus and was relatively long-limbed but had no other 'Marfanoid' features. She had a high plasma calcitonin level. At operation a normal sized thyroid gland was totally removed. It contained two discrete masses of malignant C-cells and diffuse foci elsewhere. The plasma calcitonin fell slowly to normal on follow-up but was noted to be rising 2 1/2 years later. We stress the importance of making this diagnosis as early as possible and mention briefly another child aged 15 months, similarly diagnosed and operated upon.

Plasma 25-hydroxyvitamin-D-levels during pregnancy in Caucasians and in vegetarian and non-vegetarian Asians

Plasma 25-hydroxyvitamin-D(25-O.H.D.), Ca, P, and alkaline-phosphatase levels were determined in three separate periods during pregnancy in 14 Caucasian mothers, 23 vegetarian Asians, and 16 non-vegetarian Asians. Non-pregnant women from the same group were used as controls. The expected steady rise in alkaline phosphate during pregnancy due to increase in the placental isoenzyme, and the fall in total Ca due to haemodilution, were noted. No appreciable changes in 25-O.H.D. levels occurred, but throughout pregnancy the levels in the vegetarian Asians were lower than in the other two groups. The same analyses were made in maternal and cordplasmas in some of these patients. The babies' 25-O.H.D. levels averaged 87% of their mothers'. There was no clear evidence that pregnancy as such led to increased vitamin-D requirement in any case of these groups.

Masked primary (or tertiary) hyperparathyroidism

Two patients are described in whom the preliminary clinical and laboratory investigations suggested a diagnosis of osteomalacia, from gluten-sensitive enteropathy in one and from anticonvulsant therapy in the other. However, when the primary disease was corrected by diet and extra vitamin D, respectively, both patients developed hypercalcaemia. A standard hydrocortisone test in the second patient failed to reduce the hypercalcaemia. In both patients parathyroid tumours were found at operation. It is suggested that both patients had tertiary hyperparathyroidism in which the normally tell-tale hypercalcaemia was at first masked by the other abnormalities, and that this masking may account for some cases reported as having normocalcaemic primary (or tertiary) hyperpatathyroidism. Interpretation of total plasma-calcium is likely to be unreliable unless the 25-hydroxyvitamin-D levels can be shown or assumed to be normal.

Extensive calcinosis with minimal scleroderma: treatment of ectopic calcification with aluminum hydroxide

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Successful removal of single metastasis in recurrent parathyroid carcinoma

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Five cases of alpha chain disease

Five patients suffering from alpha chain disease are described. Clinically the patients presented with clubbing and the symptoms of malabsorption. There was a characteristic, predominantly plasma cell infiltrate of the wall of the small intestine. Spread of the plasmacytosis beyond the small intestine to bone marrow (1), peripheral blood (1), and probably the nasopharyngeal lymphoid tissue (1) is described. Fragments of the heavy chain of IgA (alpha chain) were found in serum (5), urine (3), jejunal fluid (2), and saliva (1). The jejunal biopsy of one patient was shown to synthesize free alpha chain in tissue culture. A new and simple immunoselection technique for the identification of free alpha chain is described. Marked clinical remissions were achieved in two patients treated with intermittent cytotoxic and steroid therapy, and in a third patient who received intermittent cytotoxic therapy and tetracycline.

Treatment of calcinosis circumscripta with probenecid

A 23-year-old woman presented with an 11-year history of peripheral joint pains and stiffness slowly progressing to the development of gross calcinosis circumscripta. She had no definite evidence of systemic scleroderma. She was first treated for one year with frequent intravenous sodium EDTA, which increased urinary calcium and enhanced negative calcium balance but did not lessen her calcinosis. She was then treated with probenecid up to 2 g daily and her calcinosis lessened steadily over three years. Plasma levels of both phosphorus and urate fell during this time.

Rickets and osteomalacia of various origins

Further causes of rickets or osteomalacia need to be added to the list previously published by the author. These include phosphate deficiency osteomalacia from prolonged consumption of aluminum hydroxide, rickets and osteomalacia from prolonged therapy by antiepileptic drugs, rickets associated with the severe form of osteopetrosis, further rare causes of the Fanconi syndrome, congenital rickets occurring when the mother has osteomalacia from dietary causes or has celiac disease and temporary neonatal rickets probably due to enzymic immaturity. The importance is stressed of defining as closely as possible the type of rickets or osteomalacia one is dealing with, especially when considering therapy and detailed pathogenesis.

Treatment of primary hyperoxaluria

Nine patients with primary hyperoxaluria have been followed regularly for 1 to 11 years, and their treatment and progress are discussed in relation to the known natural history of the disease. 6 of them probably have the usual form of primary hyperoxaluria associated with increased glycollic acid excretion, while 3 who are sibs have the recently described variant associated with L-glyceric aciduria and normal glycollic acid excretion. All 9 patients have been on regimens designed to increase the urinary solubility of calcium oxalate, with or without the simultaneous lowering of urinary calcium and raising of urinary phosphate excretions. 8 patients have been treated for 1½-7½ years (average duration 4 years) with oral magnesium hydroxide, and 2 patients have been treated with sodium phosphate. One of the latter was changed after 3½ years to magnesium hydroxide and the other has been on sodium phosphate combined with a low calcium diet and cellulose phosphate continuously for 5½ years. 2, not at first diagnosed as hyperoxalurics, were first given sodium bicarbonate for their presumably secondary renal tubular acidosis. The over-all progress of the whole group is felt to have been better than could be expected from the known natural history of primary hyperoxaluria. They average 4¼ years on treatment during 5 years of our observation and all remain clinically well after an average of 9½ years since the onset of their first symptoms. Results warrant the recommendation that, until reliable means are available to decrease oxalate over-production, affected patients should be treated continuously with magnesium hydroxide. A more final opinion must await many more years of follow-up. The failure of several attempts to lower urinary oxalate excretion in these patients is also reported.

Osteomalacia with long-term anticonvulsant therapy in epilepsy

The investigation and treatment of osteomalacia are described in four patients with epilepsy treated with long-term anticonvulsant therapy. It is suggested that drug-mediated enzyme induction may be the mechanism responsible by causing a greatly increased inactivation of vitamin D in these patients.

Calcium metabolism in sarcoidosis

Fifteen patients with hypercalcaemia and sarcoidosis have been studied. Twelve were males of average age 34; the three females averaged 53.

Cases included widely varying sarcoid manifestations, but five gave a clear history of rather excessive ingestion of low-dosage vitamin D preparations. The data confirm that in most cases there is an undue sensitivity to all the actions of vitamin D, the situation therefore mimicking vitamin D intoxication. Two patients volunteered to receive ultra-violet irradiation and became hypercalcaemic with corresponding clinical and biochemical changes.

Steroids make normal the calcium abnormalities just as they do in straight vitamin D intoxication. However, in three further patients the hypercalcaemia did not respond to steroids and was shown to be due to the presence of an over-acting parathyroid gland, removal of which corrected the abnormality. There are a sufficient number of other similar cases in the literature to suggest that the development of parathyroid adenomas is another even rarer complication of sarcoidosis which must be carefully distinguished from vitamin D sensitivity.