[Reevaluation of validity of percent creatinuria for diagnosing steroid myopathy]

Steroid myopathy is usually a slowly progressive disease, which causes weakness primarily to the proximal muscles of the upper and lower extremities. The monitoring of this problem is difficult in situations in which the primary disease itself produces muscle weakness. The distinguishing feature in steroid myopathy is the occurrence of creatinuria in the presence of normal muscle enzymes including creatine kinase and aldolase. To evaluate the usefulness of percent creatinuria {urinary excretion of creatine/(urinary excretion of creatine + urinary excretion of creatinine)} in the diagnosis of steroid myopathy, we measured percent creatinuria in 26 patients (14 male and 12 female) without muscle diseases before the initiation of steroid treatment We found that the median values of percent creatinuria of the male and female patients were 2.5% and 17.1%, and that the ratios of the male and female patients presenting with an elevated percent creatinuria (more than 10%) were 3 out of 14 patients (21.4%) and 8 out of 12 patients (66.7%), respectively. We also found one patient with mild renal dysfunction presenting with an elevated percent creatinuria but without muscle weakness or myalgia. These findings suggest that the measurement of percent creatinuria is of little value in the diagnosis of steroid myopathy with a cutoff value of 10%. Furthermore, it is important to measure percent creatinuria before the steroid treatment, while paying close attention to the measurement method, sex, renal function and protein level of the diet.

Riboflavin therapy. Biochemical heterogeneity in two adult lipid storage myopathies

Two unrelated adult males, aged 36 (patient 1) and 25 (patient 2) years, presented with subacute carnitine-deficient lipid storage myopathy that was totally and partly responsive to riboflavin supplementation in the two patients, respectively. Plasma acyl-carnitine and urinary organic acid profiles indicated multiple acyl coenzyme A dehydrogenase deficiency, which was mild in patient 1 and severe in patient 2. The activities of short-chain and medium-chain acyl coenzyme A dehydrogenases in mitochondrial fractions were decreased, especially in patient 2. This was in agreement with Western blotting results. Flavin-dependent complexes I and II were studied by immunoblotting and densitometric quantification of two-dimensional electrophoresis with comparable results. Complex I was present in normal amounts in both patients, whereas complex II was decreased only in the pretherapy muscle of patient 2. Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) concentrations in muscle and isolated mitochondria, and the activity of mitochondrial FAD pyrophosphatase, showed that patient 1 had low levels of FAD (46%) and FMN (49%) in mitochondria, with a significant increase (P < 0.01) in mitochondrial FAD pyrophosphatase (273%) compared with controls. Patient 2 had similar low levels of FAD and FMN in both total muscle (FAD and FMN 22% of controls) and mitochondria (FAD 26%; FMN 16%) and normal activity of mitochondrial FAD pyrophosphatase. All of these biochemical parameters were either totally or partly corrected after riboflavin therapy.

[The effect of corticotherapy on respiratory muscles]

Skeletal muscle myopathy is one of the main side-effects of systemically administered corticosteroids, and involves respiratory as well as peripheral muscles. After prolonged treatment with moderate doses of either fluorinated or non-fluorinated corticosteroids, chronic myopathy may occur. In patients, such myopathy is characterized by the gradual onset of proximal limb muscle weakness and a sudden increase in creatine excretion in 24h urine. This myopathy is associated with a generalized fiber atrophy of the quadriceps in which myopathic changes are present. Since these changes were also observed in animal models, it was concluded that steroid treatment was responsible for them. After cessation of treatment, recovery of muscle force occurs but may be protracted. The severity of corticosteroid-induced myopathy appears to depend upon the type of steroid used, the treatment duration, the dose and the treatment regimen where repetitive burst treatment effects are worse than those obtained with continuous treatment with the same dose. During short-term treatment with massive doses of corticosteroids as frequently used to treat status asthmaticus, acute myopathy may develop and is characterized by generalized fiber necrosis and rhabdomyolysis. Because such necrosis was not observed in animal studies, it was suggested that the necrosis may result from the combined effect of corticosteroids with other agents such as aminoglycoside antibiotics and/or muscle relaxants.

Impaired water diuresis in a patient with pseudo-Bartter syndrome

A 32-year-old man was diagnosed as having pseudo-Bartter syndrome due to surreptitious habitual vomiting and to maldigestion related to decayed teeth. His chief complaints were muscle pain and weakness. In this case, metabolic alkalosis, hypokalemia, hypochloremia, increased plasma renin activity and aldosterone levels were noticed with marked decreases in urinary chloride excretion. Creatinine clearance (GFR) and renal plasma flow (RPF) were also decreased. Blood pressure was normal, but the pressor response to angiotensin II was attenuated. Before treatment with 0.9% saline infusion, plasma vasopressin (AVP) was not suppressed sufficiently by lowering the plasma osmolality (Posm) with an oral water load (WL), but it normally responded to a rise in Posm due to hypertonic saline infusion. Moreover, plasma AVP was normally suppressed by WL after the replenishment of saline. Plasma atrial natriuretic peptide (ANP) was low before WL, but increased normally in response to WL. However, inconsistent with the normal response in this case, decreases in plasma AVP failed to dilute urinary osmolality and to increase urine flow, irrespective of the levels of plasma ANP. These results indicate that chronic inanition due to surreptitious vomiting causes impaired renal diluting ability through decreases in GFR and RPF, irrespective of the levels of plasma AVP and ANP.

[Physiopathological aspects of secondary hyperuricemia]

Secondary hyperuricaemia expresses a heterogeneous group of clinical conditions generally classified according to the pathogenetic criteria. Hyperuricaemia can depend on an increased production, reduced renal excretion or on the combination of both. Myelo and lymphoproliferative diseases are clinically prevalent among the conditions accompanying this overproduction. The most frequent causes of reduced uric acid excretion are chronic renal failure and diuretic treatment. In recent years, several conditions of hyperuricaemia with mixed pathogenesis have revealed a common mechanism connected to the ATP cellular depletion.

Myopathy in Williams-Beuren syndrome

Williams-Beuren syndrome (WBS) is a disorder of unknown aetiology. The classical features of the syndrome include a typical ('elfin') facies, mental retardation and heart defects. Myopathy has not so far been part of the spectrum of WBS. We studied six patients with WBS aged 3-25 years, five of whom showed clinical and morphological evidence of myopathy. The clinical manifestations of myopathy included hypotonia in infancy, walking delay, joint contractures, scoliosis, and increased exhaustion on exertion. These symptoms were present in variable expression but part of a typical postural pattern. Examination of muscle biopsies showed lipid storage in four patients and increased variability of fibre size in three. In one patient a muscle biopsy gave normal results. Biochemical investigation in four patients with morphological evidence of lipid storage in muscle revealed muscle carnitine deficiency in three. In addition, enzyme activities of fatty acid beta-oxidation were low in one of two specimens tested. It is concluded that a clinically relevant myopathy is part of the multi-system manifestation of WBS and a clinical trial of carnitine supplementation is justified.

Analysis of proteinuria using a commercial system for automated electrophoresis and isoelectric focusing

We describe an investigation of proteinuria using Pharmacia PhastSystemTM electrophoresis apparatus. The analysis of urinary proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of unconcentrated urine followed by silver staining took about 2 h and could clearly demonstrate tubular dysfunction or glomerular damage in urines with a negative or only trace-positive dip-stick test for protein. In addition, we show the identification of urinary proteins by immunoblotting from SDS-PAGE gels and the characterisation of Bence-Jones proteins by isoelectric focusing (IEF) and immunoblotting.

Detection of carriers of cerebrotendinous xanthomatosis

Patients suffering from cerebrotendinous xanthomatosis (an autosomal recessive inborn error of metabolism) can easily be distinguished from patients not suffering from this disease, as the first excrete large amounts of the bile alcohol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol, in urine, whereas the second do not. In order to find out, whether carriers of cerebrotendinous xanthomatosis can be detected in a biochemical way, we compared known carriers with controls. The urinary excretions of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol of both groups were practically absent and no selection of carriers with cerebrotendinous xanthomatosis could be made on that basis. When, however, carriers and non-carriers were subjected to cholestyramine treatment, by which endogenous bile acid synthesis was stimulated, the urinary excretion of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol in the carrier rose considerably, whereas this excretion remained essentially the same in the non-carriers. This test can be of value in the genetic counseling of carriers with cerebrotendinous xanthomatosis and helpful in the detection of newborn patients with cerebrotendinous xanthomatosis.

Excretion of total and muscular N tau-methylhistidine and creatinine in muscle diseases

The daily urinary excretions of N tau-methylhistidine and creatinine from 52 adult patients were measured under standardized conditions. The ratio of N tau-methylhistidine to creatinine excretion was calculated on the basis of the total and muscle-specific excretion rates and correlated to the clinical status of the patients. In patients with muscular diseases and in those with diseases of the central nervous system, the total daily excretion of both metabolites was about 30% lower than in controls. The muscle-specific ratio in patients with diseases of the central nervous system and patients with muscular diseases was not different from that observed in controls. Only in patients with neurogenic atrophies was the ratio elevated, so that it was more than twice the control value. The ratio of excreted N tau-methylhistidine/creatinine is only valid as an indicator of myofibrillar protein breakdown after correction for the contribution of nonskeletal muscle tissues to the urinary excretion.

Urinary profile of L-carnitine and its derivatives in starved normal persons and ACTH injected patients with myopathy

Effect of starvation or ACTH injection on the urinary level and profile of L-carnitine and its derivatives was studied in four healthy adult men or in a normal child and two patients with myopathy, respectively. Mean total L-carnitine level in the control urine sample obtained before starvation was 389 +/- 34 mumol . man . day. The percentage distribution was found to be 46% for free-, 9% for acetyl- and 45% for acyl-L-carnitine. The acyl-L-carnitine fraction contained short-chain (65%) and long-chain acyl-L-carnitine (35%). With 2-day starvation urinary excretion of free-L-carnitine was slightly decreased and, in contrast, that of acetyl-L-carnitine was considerably increased, resulting in a significant increase in urinary total L-carnitine levels. Urinary excretion of acyl-L-carnitine was increased two-folds with starvation, but that of long-chain acyl-L-carnitine was not changed. In a normal child (female, 3.5 yr) and two patients (female, 4.5 yr and male, 23 yr) with myopathy, ACTH injection induced a significant elevation of urinary total L-carnitine levels, being mainly caused by an increased excretion of free-L-carnitine and, in the adult patient, acyl-L-carnitine. Muscle total L-carnitine contents were normal in two children but abnormally low in the adult patient, who had simultaneously very low urinary total L-carnitine level before ACTH injection. Thus, in the adult patient myopathy might be possibly caused in part by carnitine deficiency. Starvation and ACTH-induced changes in urinary level and profile of L-carnitine and its derivatives were discussed in relation to carnitine biosynthesis as well as renal regulation of carnitine clearance.

[Melituric picture in a group of myasthenics]

On the ground of preceding researches carried out about myodystrophias, the authors studied the melituric symptomatology in both a group of myasthenic patients and a group of control. The chromatographic analysis and the dosage of some urinary carbohydrates, showed that there are not statistically significant differences between the group of myasthenic patients and that of controls.

Nuclear medicine imaging in rhabdomyolysis

A case of severe rhabdomyolysis is reported in which, some seven and one-half weeks after its occurrence, a gallium scan was strongly positive, due to abscess formation in the damaged muscle. A bone scan was weakly positive in the same area, due to gallium photons. A review of the the reported cases reveals that bone scans are a very sensitive indicator of acute muscle damage and are useful to monitor its repair.

Creatine kinase in a biochemical test panel: the high cost of a seemingly inexpensive test

Analysis of cost-effectiveness of a laboratory test requires not only calculating the cost of doing the test in the laboratory, but also determining the clinical effectiveness of the data produced. In this hospital, creatine kinase (CK) is available only as part of a 19-test panel. The cost per CK result was $0.64, based on cost of material and labor used exclusively for CK. To evaluate the yield from CK as a screening test, 252 patients were investigated with CK greater than 200 U/l on a biochemical panel within 24 hours of admission. The authors found no instance of a new diagnosis established because of the initially elevated CK. To complete the analysis of cost-effectiveness, the authors estimated the daily workload for CK tests needed for diagnostic purposes. Of the 600 CK tests done daily as part of biochemical panels, no more than 40 were clinically necessary. The true cost for a useful CK test was $9.60--15 times higher than the apparent cost of $0.64.

Acid-base and electrolyte alterations in horses with exertional rhabdomyolysis

In examination of the acid-base and electrolyte status of 7 horses with acute exertional rhabdomyolysis, the most consistent abnormality was hypochloremia. Metabolic acidosis was not evident in any of the horses. Therefore, the use of sodium bicarbonate in treatment of such disorders may not be indicated in all cases.

Increased rates of myofibrillar protein breakdown in muscle-wasting diseases

The excretion of endogenous creatinine and 3-methylhistidine by subjects with muscle diseases has been measured in order to assess muscle mass and fractional rates of myofibrillar protein degradation. Increases in the rates of myofibrillar protein breakdown were observed in all subjects with Duchenne, Becker, autosomal recessive Duchenne-like, and limb-girdle muscular dystrophy; dystrophia myotonica; myotonia congenita; peroneal muscular atrophy; myasthenia gravis; and central core disease; in some cases of spinal muscular atrophy; but in no cases of facioscapulohumeral muscular dystrophy of dystonia musculorum deformans. All increases in myofibrillar protein breakdown were associated with reductions in muscle proportion below the normal. Muscle-wasting diseases may respond to therapy directed towards an inhibition of muscle protease activity; the efficacy of such therapy can be monitored by the 3-methylhistidine-to-creatinine excretion ratio.

Rhabdomyolysis associated with urethral stricture repair: report of a case

A case is reported of rhabdomyolysis and acute tubular necrosis following an exaggerated knee-chest position to repair a urethral stricture. To our knowledge this is the first case reported of this syndrome occurring after a urologic procedure.

Decrease of 3-methylhistidine and increase of NG,NG-dimethylarginine in the urine of patients with muscular dystrophy

The amounts of 3-methylhistidine, N epsilon,N epsilon-dimethyllysine, N epsilon, N epsilon, N epsilon-trimethyllysine, NG,NG-dimethylarginine, and NG,N'G-dimethylarginine were determined in the urine specimens of healthy subjects and patients of corresponding ages with Duchenne, limb-girdle, and congenital types of muscular dystrophy, and motor neuron diseases. The amount of excretion of 3-methylhistidine decreased and that of NG,NG-dimethylarginine increased significantly in Duchenne and limb-girdle types of muscular dystrophy, but not in diseases with neurogenic muscular atrophy. The decrease of 3-methylhistidine was observed consistently throughout the course of the Duchenne type of muscular dystrophy. The amounts of the other methylamino acids both in myogenic and neurogenic myopathies were not different from those in healthy subjects.

The pattern of urinary catecholamines and their metabolites in Duchenne myopathy, in relation to disease evolution

In this report we have tried to determine whether or not catecholamines are involved in the progressive muscular dystrophy. Catecholamines and their metabolites were studied in urines of children with Duchenne disease or other forms of myopathy (limb-girdle and facio-scapulo humeral myopathies). Catecholamine deaminated metabolites were normal in either form of myopathy; in contrast, Duchenne patients, contrarily to other children, eliminated excessive amounts of most amines (catecholamines and methoxylated amines) in relation to age and degree of disease evolution. Our results indicate that catecholamines are not the primary factors involved in the pathogenesis of Duchenne myopathy, but are rather secondary to some disease effects. It is suggested that the high excretion of catecholamines and their methoxylated amine metabolites observed in severely affected Duchenne boys might be related to thermoregulatory process or/and to alterations in some enzymatic systems.

Heroin-associated rhabdomyolysis with cardiac involvement

A heroin addict had rhabdomyolysis with cardiac involvement. The patient was admitted with edema of the right leg and oliguria. Admission diagnoses were right illofemoral thrombophlebitis, acute renal failure, and heroin addiction. Urinalysis was strongly positive for "blood" in the absence of hemolysis or marked hematocyturia, and a diagnosis of rhabdomyolysis was made. Peritoneal dialysis succeeded in lowering blood urea nitrogen and serum potassium levels, but the patient died on the fourth hospital day. Postmortem examination disclosed focal myocardial myolysis, diffuse rhabdomyolysis of the right soleus muscle, and acute renal tubular necrosis. Direct toxicity or hypersensitivity to heroin or an adulterant is considered in the pathogenesis of myolysis.

Diagnostic meaning of the urinary output of Nepsilon-methylated lysines. Investigation of healthy individuals and patients with malignant diseases, myopathies or renal failure

In the urine of 36 healthy persons the excretion of the three Nepsilon-methylated lysines and some other basic amino acids was determined. The following average values, related to 1 g creatinine, were found: Lys(Me) 16.2 mumol, Lys(Me2) 31.2 mumol, Lys(Me3) 40.5 mumol. The 24-hour excretion in 6 adults related to 1 kg body weight, had the following average values: Lys(Me) 0.37 mumol, Lys(Me2) 0.88 mumol, Lys(Me3) 0.92 mumol. In patients with degenerative or inflammatory myopathies (6 cases) as well as with generalized tumors (7 cases) urinary output of methyllysines was not significantly altered. In a patient with extremely impaired renal function, it was found that the plasma level and the excretion pattern of the methylated lysines were unequivocally altered. Metabolic stability and renal excretion of 3H-labelled l-Lys(Me3) were investigated in man. During a 24 hour period 65 per cent of Lys(Me3) was excreted into the urine unmetabolized after intravenous injection but not more than 20 per cent after oral administration.