IDIOPATHIC PAROXYSMAL MYOGLOBINURIA WITH ACUTE RENAL FAILURE AND HYPERCALCEMIA

Bone scintigraphy of severe hypercalcemia following simvastatin induced rhabdomyolysis

Simvastatin induced rhabdomyolysis with renal failure is a well reported clinical entity with hyperkalemia recognized as a life threatening risk. The risk of delayed hypercalcemia during the recovery of renal function is not well appreciated as this varies in severity and can be caused by multiple mechanisms. We present a patient with high dose simvastatin induced rhabdomyolysis leading to late onset of severe hypercalcemia due to calcium phosphate deposition in muscles diagnosed by distinctive bone scintigraphy. A 60-year-old Asian male was admitted to the hospital for profound weakness one week following the initiation of simvastatin 80 mg daily post myocardial infarction. His clinical course was complicated by contrast nephropathy. One week later, he developed progressive weakness in all his extremities and inability to raise his head and eat. Simvastatin was discontinued at this point. CPK elevation to greater than 425,000 U was found, consistent with rhabdomyolysis. He became oliguric requiring hemodialysis. Muscle biopsy showed severe muscle necrosis and type 2 fiber atrophy. One month later, he developed hypercalcemia with suppressed intact PTH and 1, 25(OH) D levels. Whole body bone scintigraphy showed calcium phosphate deposition throughout his musculature. His calcium levels normalized in 1 week on hemodialysis. This patient's experience illustrates the marked risk of delayed severe hypercalcemia from rhabdomyolysis due to dissolution of myocellular calcium phosphate deposits. It also provides an opportunity to review the different mechanisms of hypercalcemia especially in statin induced rhabdomyolysis. Recognition of this phenomenon is critical for appropriate follow up and treatment of such patients.

Case report: delayed hypercalcemia after rhabdomyolysis-induced acute renal failure

Abnormal calcium metabolism is a common complication of rhabdomyolysis -induced acute renal failure. During the oliguric phase, patients are frequently hypocalcemic. Hyperphosphatemia and skeletal resistance to parathyroid hormone are believed to be possible underlying mechanisms. In addition, there have been reports of hypercalcemia during the diuretic recovery phase after rhabdomyolysis. The pathophysiology of the hypercalcemia observed in the recovery phase is a subject of debate. Several mechanisms have been proposed, including mobilization of calcium from muscle deposits, secondary hyperparathyroidism, and elevated levels of 1,25 dihydroxyvitamin D. The authors report the case of a 30-year-old man admitted for evaluation of marked hypercalcemia (18.3 mg/dL) who was hospitalized 3 weeks earlier for acute renal failure secondary to rhabdomyolysis. Plasma parathyroid hormone and 1,25 dihydroxyvitamin D levels were suppressed during the period of maximal hypercalcemia. A technetium pyrophosphate scan demonstrated extensive deposition of calcium throughout the pelvic and lower extremity muscles. This case of delayed hypercalcemia after rhabdomyolysis supports the hypothesis that mobilization of calcium deposits from soft tissue, including muscle, is central to the pathogenesis of this syndrome.

Myoglobinemia and endurance exercise: a study of twenty-five participants in a triathlon competition

Twenty-five athletes competing in a triathlon, an endurance competition, were studied to determine the relationship of sustained muscle exertion with myoglobinemia and clinical rhabdomyolysis. Of 24 athletes who completed the event, each individual demonstrated a dramatic rise and fall in serum myoglobin over a 24 hour period, with an average peak level of 842 ng/ml. While all subjects exhibited symptoms of myalgia after exertion, none required hospitalization. A significant correlation was demonstrated with average serum myoglobin and finishing time (P less than 0.0125) and postexercise temperature (P less than 0.05). Appropriate training of individuals, whether athletes or military recruits, appears to be an important factor in reducing myoglobinemia. Exercise-induced myoglobinemia appears to be dependent on intensity of athletic performance, measured as a function of time, distance, and activity performed. The athletes who finished first had the highest levels of myoglobinemia.

Hypercalcaemia in association with renal failure: the role of immobilisation

Hypercalcaemia occurring after ten weeks of immobilisation was observed in four adult patients all of whom had had prior renal failure sufficient to require renal dialysis. In all patients parathyroid hormone levels were normal or low and in three plasma 1,25(OH)2D3 levels were low. These findings are consistent with immobilisation induced increases in bone calcium resorption. Renal excretion of calcium may have been impaired by renal dysfunction resulting in hypercalcaemia and suppression of plasma PTH and 1,25(OH)2D3 levels. Resolution of the hypercalcaemia was associated with remobilisation. Parathyroidectomy is inappropriate treatment.

Hypophosphatemia-induced hypercalcemia during acute renal failure

A case of hypophosphatemia-induced hypercalcemia during post-traumatic acute renal failure is described. Proposed causes for the hypophosphatemia include changes in tissue distribution of phosphate associated with hyperalimentation and phosphate losses during hemodialysis. In the absence of hyperparathyroidism the hypercalcemia as well as changes in osteoclast morphology found on bone biopsy are ascribed to a direct effect of hypophosphatemia on bone.

Dialytic support of dogs with clinically occurring renal failure: a realistic model of acute renal failure in man

In canine veterinary medicine, both acute and chronic renal failure occur relatively frequently, from a variety of causes similar to those in man. However, the normal dog has a very high protein catabolic rate and high endogenous kidney function, and, therefore, requires frequent and highly efficient dialysis, for maintenance during renal failure. We have developed techniques to support the uremic dog with hemodialysis. An experimentally anephric dog, and two dogs with clinically occurring acute renal failure (caused by ethylene glycol intoxication and heat stroke) have been supported with frequent use of hollow fiber dialyzers, using a carotid artery to jugular vein shunt. Patency of shunts was maintained by administration of oral aspirin. A very high urea and creatinine generation rate necessitated daily dialysis during much of the clinical course of renal failure. The experimentally anuric animal was supported for 35 days. The ethylene glycol-induced renal failure animal was euthanized on the 21st day, and the heat stress-induced renal failure animal recovered sufficient intrinsic renal function after 16 days of dialysis for maintenance of life without dialysis.

Suppressive effects of 24,25-dihydroxycholecalciferol on bone resorption induced by acute bilateral nephrectomy in rats

The possible suppressive effects of 24,25-dihydroxycholecalciferol on secondary hyperparathyroidism and increased bone resorption were investigated in adult rats raised on a diet normal in calcium, phosphorus, and vitamin D, and subjected to acute bilateral nephrectomy. The animals had received subcutaneous radiocalcium 4 wk before the experiment. 5 h after nephrectomy an increase in serum total calcium, (45)Ca-specific activity, citrate, phosphorus, and magnesium concentrations were observed. Serum immunoreactive parathyroid hormone increased, while serum calcitonin decreased. The osteoclast count in the tibial metaphyses was augmented. The biochemical and histological changes observed were partly parathyroid hormone and calcitonin independent, as they also occurred in parathyroidectomized hypocalcemic rats. Pretreatment with 650 pmol of 24,25-dihydroxycholecalciferol 16 h before nephrectomy prevented bone calcium mobilization and diminished the rise in serum total calcium and citrate both in parathyroid-intact and in parathyroidectomized animals. In parathyroid-intact rats, serum immunoreactive parathyroid hormone and calcitonin remained normal in spite of the fall in serum-ionized calcium, and the number of osteoclasts did not increase. In parathyroidectomized rats, 24,25-dihydroxycholecalciferol did not prevent the postnephrectomy rise in the osteoclast count. This latter observation suggests that this metabolite exerts its effect on bone either by acting on cells other than osteoclasts, i.e., the osteocytes, or by inhibiting cell activity. At equimolar dosage 1,25-dihydroxycholecalciferol had a potent stimulatory effect on bone resorption. This effect of 1,25-dihydroxycholecalciferol was partly blocked by the simultaneous administration of 24,25-dihydroxycholecalciferol. The potential clinical significance of these observations remains to be determined.

The pathophysiology of altered calcium metabolism in rhabdomyolysis-induced acute renal failure. Interactions of parathyroid hormone, 25-hydroxycholecalciferol, and 1,25-dihydroxycholecalciferol

We studied six oliguric patients with rhabdomyolysis-induced acute renal failure. On admission, all had marked hyperphosphatemia and hypocalcemia associated with low levels of 1,25-dihydroxycholecalciferol [1,25(OH)2D]. During the early polyuric phase, moderate hypercalcemia was accompanied by marked elevations in plasma 1,25(OH)2D and persistent elevations in parathyroid hormone (both amino and carboxy terminals). During the late polyuric phase, the levels of serum calcium and 1,25(OH)2D reverted to normal. Thus, in rhabdomyolysis-induced acute renal failure, the hypocalcemia of the oliguric phase may be secondary to decreased synthesis of 1,25(OH)2D; severe hyperphosphatemia may also have a major role. The hypercalcemia of the polyuric phase may be partly due to increased synthesis of 1,25(OH)2D, resulting from the high parathyroid hormone levels and recovery of renal function.

Acute drug-associated rhabdomyolysis: an examination of its diverse renal manifestations and complications

Thirty patients with drug associated acute nontraumatic rhabdomyolysis were evaluated. Acute renal failure, oliguric (ORF) in ten and nonoliguric (NORF) in another ten patients, was observed. The remaining ten patients did not develop renal failure (NRF). To identify factors that may have contributed to this clinical diversity, these three groups were compared. Data from 51 patients reported in the literature were also included in the analysis. The patients with ORF were slightly younger than patients with NORF. They had higher incidence of muscle swelling and higher serum potassium. ORF was more severe, lasted longer, and required more dialysis than NORF. The group of patients with renal failure had higher incidence of coma and more patients with very high muscle enzyme elevation than NRF patients. Hypercalcemia, a unique complication of rhabdomyolysis, was reported in 22 patients. It was not seen in patients without renal failure. There were no differences in age, incidence of coma, muscle swelling, and muscle enzyme between those who did and those who did not develop hypercalcemia. Sixteen patients with nerve entrapment had higher incidence of coma and muscle swelling than the rest of the patients.

Acute renal failure due to non-traumatic rhabdomyolysis

Seventeen patients with acute renal failure of diverse aetiology showed myoglobinuria and elevated levels of serum creatine phosphokinase (mean 119·2 Sigma u./ml) and adolase (mean 88·5 Sibley-Lehninger (SL)u./ml), indicating the presence of diffuse muscle cell injury. The primary conditions which led to rhabdomyolysis and acute renal failure were burns, eclampsia, prolonged labour, crush injury, epileptiform convulsions, status asthmaticus, viral myositis and intoxication with chemicals including copper sulphate, mercuric chloride and zinc phosphide. In 10 non-myoglobinuric patients with acute renal failure, serum creatine phosphokinase was normal (mean 8·9 Sigma u./ml) and serum aldolase was only slightly elevated (mean 11·2 SL u./ml). Although uric acid was elevated in both groups, the values were significantly higher in myoglobinuric (mean 0·728 ± 0·199 mmol/l) compared to non-myoglobinuric patients (mean 0·583 ± 0·093 mmol/l). During the oliguric phase, hypocalcaemia was observed in 82·2% of myoglobinuric patients and in 20% of non-myoglobinuric patients. Ten out of 15 patients with myoglobinuric renal failure developed hypercalcaemia during the diuretic phase whereas only 3 non-myoglobinuric patients showed a transient hypercalcaemia. Although the mean serum potassium was somewhat higher in the myoglobinuric patients, the difference between the 2 groups was not significant. It is concluded that acute renal failure associated with non-traumatic rhabdomyolysis is not infrequent and may occur in a variety of conditions where gross evidence of muscle injury is lacking.

Transient hypercalcaemia following acute renal failure

Two patients with transient hypercalcaemia during recovery from acute renal failure are described. The literature is reviewed and possible pathophysiological mechanisms discussed. Patients with renal failure following muscle damage should have regular measurement of plasma calcium.

Heat illness. II. Pathogenesis

The effects of elevated temperatures and the time-temperature combinations for irreversible damage are outlined. Coagulation abnormalities and the effects on the kidney, liver, heart, brain and serum enzymes, the role of electrolytes and water, including salt deficiency and the controversial question of salt supplements, potassium deficiency, changes in other electrolytes and sweat solutes, and rhabdomyolysis (including a discussion of experimental work on dogs) are reviewed. The section ends with a discussion of the effects of drugs and an account of a recent fatal case of heat stroke which may have been triggered by chlorpromazine therapy.

Idiopathic rhabdomyolysis

The clinical, biochemical, and pathological findings in 2 children with idiopathic rhabdomyolysis are reported. Hypocalcaemic tetany, a previously unrecognized complication of severe muscle damage, was seen in one child and was associated with hyperphosphataemia and hyperphosphaturia consequent on the rhabdomyolysis. Respiratory distress and an acute tubular necrosis contributed to her eventual death. The second child recovered; an intracellulr granular material of unknown nature was seen in his muscle biopsy on electron microscopy. The literature of idiopathic recurrent rhabdomyolysis occurring in childhood is reviewed.

Muscle necrosis and acute renal failure in carbon monoxide poisoning

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