Biopsy proven evolution of post streptococcal glomerulonephritis to rapidly progressive glomerulonephritis of a post infectious type.

A 15 year old boy with chronic impetigo was admitted with severe acute oliguric renal failure requiring temporary dialytic treatment. Renal biopsy revealed typical diffuse and proliferative glomerulonephritis of the poststreptococcal type. Subsequently high temperature developed with flank pains at the biopsy site, concomitantly with deterioration of renal function. On exploration, a sterile perirenal hematoma was found and a wedge renal biopsy revealed crescentic rapidly progressive glomerulonephritis of the post infectious type. Deterioration to end stage renal failure occurred within a few months. Although universally accepted, biopsy proven evolution from diffuse proliferative and exudative glomerulonephritis to crescentic form of post streptococcal glomerulonephritis has been rarely reported.

Induction of chronic renal failure in the mouse: a new model.

An animal model with experimental uremia is an important research tool for the study of the sequence of pathophysiological events taking place in the uremic syndrome. An appreciable number of animal models and methods for the induction of chronic uremia have been published. It is surprising that no such method has been reported in the mouse, which is an important laboratory animal. A new method for the induction of chronic uremia in the mouse is described. It consists of unilateral destruction of most of the renal cortex by burns combined with contralateral nephrectomy. This method can be carried out in one or two stages. Follow-up of the experimental animals reveals that significant uremia developed within 4 weeks and remained constant for the rest of the study period, i.e. 10 weeks.

Breast mycobacterial infection in a haemodialysis patient.

Mycobacterial infection is relatively common among patients maintained on haemodialysis and may present in uncommon locations and acquire an unusual course. We present a patient in whom a breast mass was found to be caused by primary mycobacterial infection. This is to our knowledge the first report on breast mycobacterial infection in a haemodialysis patient.

Eosinophilia in uremia.

Peripheral and bone marrow eosinophils were determined in a group of patients on chronic hemodialysis and in predialysis uremics. Healthy subjects were taken as controls. Increased number of eosinophils in bone marrow were found in the predialysis uremic group and this finding was even more accentuated in the dialyzed patients. Marrow eosinophilia correlated linearly with serum creatinine levels in the predialysis group. The peripheral eosinophil count was normal in the uremic group and in part of the hemodialysis group. Marked and progressive peripheral eosinophilia was evident in a distinct subgroup of the dialysis patients. Marrow eosinophilia seems to be part of the uremic syndrome. The possible nature of the factor(s) involved in the derangement of eosinophil homeostasis is discussed.

Hyperoxaluria is not a cause of nephrocalcinosis in phosphate-treated patients with hereditary hypophosphatemic rickets.

The treatment of X-linked hypophosphatemia (XLH) consists of phosphate and vitamin D3 derivatives. Transient hypercalciuria and hypercalcemia are well-known signs of vitamin D intoxication. Despite urinary calcium excretion control, the danger of nephrocalcinosis in treated patients has been emphasized. It has recently been suggested that hyperoxaluria might be a causative factor of nephrocalcinosis other than calcium in phosphate-treated XLH patients. We measured urinary oxalate and phosphate excretion in 12 patients with the syndrome of hereditary hypophosphatemic rickets with hypercalciuria (HHRH) receiving only oral phosphates and in 5 XLH patients receiving both oral phosphates and vitamin D. No correlation was found between the dosage of phosphate supplements or urinary phosphate excretion and urinary oxalate excretion, in either group of patients. Nephrocalcinosis, presenting as hyperechogenicity of the medullary pyramids, was found in 2 of the 5 XLH patients and only in 2 HHRH patients who had been treated with excessive doses of vitamin D2 and calcium, prior to the true diagnosis being established. We conclude: (1) hyperoxaluria is not a cause of nephrocalcinosis in phosphate-treated patients with hereditary hypophosphatemic rickets; (2) prolonged phosphate treatment alone does not induce nephrocalcinosis in HHRH patients, and (3) we believe that in XLH patients, nephrocalcinosis is essentially due to vitamin D overdosage at some stage, or noncompliance in phosphate intake, leading to repeated undetected hypercalciuric periods.

Hereditary hypophosphatemic rickets with hypercalciuria.

We studied a new hereditary syndrome of hypophosphatemic rickets and hypercalciuria in six affected members of one kindred. In all patients, the manifestations of disease began in early childhood. The characteristic features are rickets, short stature, increased renal phosphate clearance (the ratio between the maximal tubular reabsorption rate for phosphorus and the glomerular filtration rate [TmP/GFR] is 2 to 4 S.D. below the age-related mean), hypercalciuria (8.6 mg of urinary calcium per kilogram of body weight per 24 hours vs. the upper normal value of 4.0), normal serum calcium levels, increased gastrointestinal absorption of calcium and phosphorus, an elevated serum concentration of 1,25-dihydroxyvitamin D (390 +/- 99 pg per milliliter vs. the upper normal value of 110), and suppressed parathyroid function (an immunoreactive parathyroid hormone level of 0.33 +/- 0.1 ng per milliliter and a cyclic AMP level of 1.39 +/- 0.12 nmol per deciliter of glomerular filtrate vs. the lower normal values of 0.3 and 1.5, respectively). Long-term phosphate supplementation as the sole therapy resulted in reversal of all clinical and biochemical abnormalities except the decreased TmP/GFR. We propose that the pivotal defect in this syndrome is a renal phosphate leak resulting in hypophosphatemia with an appropriate elevation of 1,25-dihydroxyvitamin D levels, which causes increased calcium absorption, parathyroid suppression, and hypercalciuria. This syndrome may represent one end of a spectrum of hereditary absorptive hypercalciuria. Our observations support the importance of phosphate as a mediator in controlling 1,25-dihydroxyvitamin D production in human beings.

Hypercalciuric rickets: metabolic studies and pathophysiological considerations.

Extensive metabolic studies were performed in a 14-year-old boy suffering from the rare clinical entity known as childhood idiopathic hypercalciuria associated with dwarfism, renal tubular abnormalities and bone lesions. The salient features were: hyperphosphaturia with hypophosphatemia, hypercalciuria with normocalcemia, elevated serum 1,25-dihydroxycholecalciferol[1,25(OH)2D3] levels, marked intestinal hyperabsorption of calcium and phosphorus, with low serum parathyroid hormone (PTH) and urinary adenosine 3':5'-cyclic monophosphate (c-AMP). Bone biopsy confirmed the clinical and radiological diagnosis of rickets. It appears that the following pathophysiological sequence is operating: primary renal phosphate leak with hypophosphatemia, increased 1,25(OH)2D3 synthesis, enhanced intestinal calcium absorption which in turn inhibits release of PTH and c-AMP. Hypercalciuria is seen to be secondary to both avid intestinal calcium absorption and depressed PTH activity, and rickets the result of phosphate depletion. Treatment with oral phosphorus only resulted in an acceleration of growth rate, cure of rickets, and return of urinary calcium excretion to normal values.

Vitamin D resistant rickets with alopecia: a form of end organ resistance to 1,25 dihydroxy vitamin D.

A 4-year-old girl presented with severe clinical and radiological rickets, and alopecia since the age of 1 year. Laboratory studies revealed: hypocalcaemia, hypophosphataemia, secondary hyperparathyroidism, abnormally low intestinal calcium absorption, and markedly elevated circulating 1,25(OH)2D3 levels. A normal calcaemic response to parathyroid extract was obtained. Treatment attempts with vitamin D2, 1 alpha (OH)D3 and 1,25(OH)2D3 were totally ineffective. Intestinal resistance to the action of 1,25(OH)2D3 appeared well established in this case. Refractoriness of bone to this hormone seems less certain. From this new entity of 'Vitamin D resistant rickets due to end organ unresponsiveness', six cases have been hitherto reported in the literature. However, only two have enough resemblance to our case, to constitute a distinct and well defined nosologic subunit. The molecular basis of this disorder(s) remains to be elucidated.