Clinical features of patients with dystrophinopathy sharing the 45-55 exon deletion of DMD gene.

Becker muscular dystrophy (BMD) was first described in 1953 by Emile Becker as a benign variant of Duchenne muscular Dystrophy (DMD). Compared with DMD, BMD is clinically more heterogeneous, with initial presentation in the teenage years and loss of ambulation beyond the age of 16 and a wide spectrum of clinical presentations, ranging from only myalgias and muscle cramps to exercise intolerance and myoglobinuria, asymptomatic elevation of serum creatin-kinase, or mild limb-girdle weakness and quadriceps myopathy. About 50% of patients become symptomatic by the age of 10 and the most part by the age of 20 years. However few patients can be free of symptoms till their fifties and cases of late-onset Becker Muscular Dystrophy have also been described. In this report we describe the clinical features of patients with dystrophinopathy sharing a deletion of exons 45-55, occasionally or retrospectively diagnosed. These data are important for both the prognostic aspects of children presenting this dystrophin gene mutation, and for the genetic counseling in these families (reassuring them on the benign course of the disease), and last but not least to keep in mind a diagnosis of BMD in asymptomatic adults with mild hyperckemia.

Rhabdomyolysis in a recreational swimmer.

Rhabdomyolysis is a clinical and biochemical syndrome resulting from skeletal muscle injury, which may ultimately lead to acute renal failure (ARF) and death. Exertional rhabdomyolysis refers to skeletal muscle injury that is usually induced by strenuous eccentric exercises in a hot and humid environment. It is usually seen in marathoners and military personnel. We present the case of a 32-year-old Malaysian man who had rhabdomyolysis and myoglobinuria without ARF after two episodes of unaccustomed swimming. He was treated conservatively, and recovered uneventfully. A brief discussion on the pathophysiology of rhabdomyolysis, the principles of management and recuperation is included.

Insuficiencia renal aguda por picadura múltiple de abejas africanizadas. Comunicación de 43 casos / Acute renal failure due to multiple stings by Africanized bees. Report on 43 cases

Se comunican 43 casos de insuficiencia renal aguda (IRA) por picadura múltiple de abejas africanizadas (AA) recopilados entre 1982 y 2007 en la Sección de Nefrología de la Universidad de Antioquía y el Hospital San Vicente de Paúl, de Medellín, Colombia. No se realizó ninguna intervención diferente a responder la interconsulta a nefrología y a ordenar los procedimientos de diálisis. Los datos obtenidos de las historias clínicas incluyeron datos demográficos; presentación clínica; exámenes de laboratorio realizados en el momento del ingreso; evolución de función renal para documentar la mejoría y la curación de la IRA; intervalos entre picaduras y desenlaces; número de sesiones de diálisis; duración del seguimiento y la hospitalización; supervivencia, y mortalidad. Los datos no fueron completos en los 43 casos; por ello se expone el número exacto de observaciones cuando corresponde. Edad promedio: 56 ± 26 años (rango, 2-96); 37 (86%) fueron hombres; 38 (de 41 con datos) procedían del área rural (91%); 22 de 39 fueron agricultores (56,4%); 33 de 41 provinieron de la ciudad de Medellín o el departamento de Antioquía (80,5%). Número de picaduras por paciente: aproximadamente 900. Intervalo entre picadura múltiple e IRA <48 horas: 31 casos (72,1%; promedio 2,6 ± 2,6 días; rango, 1-12); 37 de 43 requirieron diálisis (86%); promedio de sesiones: 4,7 ± 3,3 (rango, 1-12). Supervivencia: ocurrió en 36 casos (83,7%); mortalidad: en siete, todos >60 años (16,3%). La mejoría de la función renal se produjo en 36 casos (83,7%) y la normalización en 15 de los 36 casos (41,7%). El intervalo hasta el inicio de la diuresis fue de 10,6 ± 6,8 días (rango, 1-25). La duración de la hospitalización fue de 16,9 ± 8,7 días (rango, 1-39). El seguimiento fue de 25,2 ± 18,3 días (rango, 1-75). Hematuria y oliguria se produjeron antes de 24 horas de las picaduras; hubo elevación de CPK en el 90%, de ALT en el 96%, de AST en el 89%, de láctico-deshidrogenasa en el 95%, y de BUN y creatinina en el 100%. Basándonos en nuestros hallazgos y en la revisión de la información de la que disponemos, postulamos que este tipo de IRA se produce como resultado de rabdomiólisis con mioglobinuria subsiguiente, lo que desencadena una necrosis tubular aguda nefrotóxica; probablemente influye, además, algún grado de nefrotoxicidad directa no cuantificable con los métodos diagnósticos actuales. Un mayor conocimiento de esta entidad por parte de la comunidad médica puede ayudar a mejorar el tratamiento y el pronóstico de los pacientes que la presentan (AU)

Acute renal failure due to multiple stings by Africanized bees. Report on 43 cases. This study reports on acute renal failure (ARF) due to multiple stings by Africanized bees (AB) occurring in 43 cases collected between 1982 and 2007 (at the Nephrology Section, University of Antioquia School of Medicine and San Vicente de Paul University Hospital, Medellin, Colombia). No intervention on patient care was performed except for responding the Nephrology consult and prescribing dialysis. Data obtained from the medical records included demography; clinical presentation; laboratory results on admission; evolution of renal function to document improvement and normalization; intervals between stings and outcomes; number of dialysis sessions; length of follow-up and hospitalization; survival; and mortality. Not all patients had complete data and therefore, the number of observations is included where required. Mean age was 56 ± 26 yr (range 2–96); 37 (86%) were men; 38 (of 41 cases) came from rural areas (91%); 22 (of 39) were farmers (56.4%); 33 (of 41) lived in Medellin or in the department of Antioquia (80.5%). Number of stings per patient: ~ 900. Interval between stings and ARF < 48 hours: in 31 cases (72.1%; mean 2.6 ± 2.6 days; range 1–12); 37 (of 43) required dialysis (86%); mean number of sessions: 4.7 ± 3.3 (range 1–12). Survival occurred in 36 cases (83.7%) and mortality, in 7, all > 60 yr (16.3%). At last follow-up, renal function improvement was documented in 36 (83.7%) and normalization in 15 of them (41.7%). Interval until initiation of diuresis: 10.6 ± 6.8 days (range 1–25). Duration of hospitalization: 16.9 ± 8.7 days (range 1–39). Follow-up: 25.2 ± 18.3 days (range 1–75). Hematuria and oliguria occurred before 24 hours; there was an increase of CPK in 90%, of ALT in 96%, of AST in 89%, of DHL in 95%, and of BUN and creatinine in 100%. Based on our findings and on the review of the available information, we propose that this type of ARF occurs as a result of rhabdomyolysis with subsequent myoglobinuria, which lead to nephrotoxic acute tubular necrosis; a variable degree of direct nephrotoxicity, not quantifiable with current diagnostic methods, is also probably involved. A better knowledge of this entity by the medical community could improve care and prognosis of the patients who develop it (AU)

New-generation Skulachev ions exhibiting nephroprotective and neuroprotective properties.

A mitochondria-targeted chimeric compound consisting of a rhodamine derivative linked to a plastoquinone molecule (10-(6'-plastoquinonyl)decylrhodamine, SkQR1) was studied under conditions of acute brain or kidney damage. A protective effect of this compound was demonstrated in a model of focal brain ischemia, rat kidney ischemia/reperfusion, myoglobinuria (rhabdomyolysis, or crush syndrome), and pyelonephritis. We found that a single intraperitoneal injection of SkQR1 diminishes the size of the ischemic zone in the brain and improves performance of a test characterizing neurological deficit in ischemic animals. Control substance not containing plastoquinone appeared to be not neuroprotective. The data show that SkQR1 is a nephroprotectant and neuroprotectant, which can be due to the antioxidative action of this Skulachev cation.

Myopathy and parkinsonism in phosphoglycerate kinase deficiency.

A 25-year-old man with exertional myoglobinuria had no evidence of hemolytic anemia, but he had severe parkinsonism that was responsive to levodopa. Phosphoglycerate kinase (PGK) activity was markedly decreased in muscle, and molecular analysis of the PGK1 gene identified the p.T378P mutation that was recently reported in a patient with isolated myopathy. This case reinforces the concept that PGK deficiency is a clinically heterogeneous disorder and raises the question of a relationship between PGK deficiency and idiopathic juvenile Parkinson disease.

Deaths in custody: are some due to electronic control devices (including TASER devices) or excited delirium?

Deaths have occurred after law-enforcement incidents involving applications of electronic control devices (ECDs) (including TASER devices). An "excited delirium" syndrome (reported in the literature prior to the development of ECDs currently in use), however, includes several factors that may be related to such deaths in custody. In this review, potential detrimental effects of ECDs are compared with possible changes due to excited delirium. Although extreme (i.e., long-duration or repeated) exposures to ECDs can result in significant hyperkalaemia, acidaemia, and myoglobinemia in animal models, limited applications (such as those normally used in law-enforcement situations) would appear to have only transient effects. In addition, the hyperthermia observed in patients with excited delirium does not seem to be directly exacerbated by ECD applications. ECD use is unlikely to be a common cause of ventricular fibrillation, but other events that are generally associated with excited delirium (e.g., drug use) may be related to subsequent ventricular fibrillation or asystole. Metabolic or respiratory acidosis may only be serious consequences of long-duration or repeated ECD applications. On the basis of current available information, factors other than ECDs themselves may be more important when death occurs after the use of ECDs.

Rhabdomyolysis: a review of the literature.

Rhabdomyolysis is a potentially life-threatening syndrome that can develop from a variety of causes; the classic findings of muscular aches, weakness and tea-coloured urine are non-specific and may not always be present. The diagnosis therefore rests upon the presence of a high level of suspicion of any abnormal laboratory values in the mind of the treating physician. An elevated plasma creatine kinase (CK) level is the most sensitive laboratory finding pertaining to muscle injury; whereas hyperkalaemia, acute renal failure and compartment syndrome represent the major life-threatening complications. The management of the condition includes prompt and aggressive fluid resuscitation, elimination of the causative agents and treatment and prevention of any complications that may ensue. The objective of this review is to describe the aetiological spectrum and pathophysiology of rhabdomyolysis, the clinical and biological consequences of this syndrome and to provide an appraisal of the current data available in order to facilitate the prevention, early diagnosis and prompt management of this condition.

The place of suxamethonium in pediatric anesthesia.

Suxamethonium is a drug that promotes very strong views both for and against its use in the context of pediatric anesthesia. As such, the continuing debate is an excellent topic for a 'Pro-Con' debate. Despite ongoing efforts by drug companies, the popular view still remains that there is no single neuromuscular blocking drug that can match suxamethonium in terms of speed of onset of neuromuscular block and return of neuromuscular control. However, with this drug the balance of benefit vs risk and side effects are pivotal. Suxamethonium has significant adverse effects, some of which can be life threatening. This is particularly relevant for pediatric anesthesia because the spectrum of childhood diseases may expose susceptible individuals to an increased likelihood of adverse events compared with adults. Additionally, the concerns related to airway control in the infant may encourage the occasional pediatric anesthetist to use the drug in preference to slower onset/offset drugs. In the current environment of drug research, surveillance and licensing, it is debatable whether this drug would achieve the central place it still has in pediatric anesthesia. The arguments for and against its use are set out below by our two international experts, Marcin Rawicz from Poland and Barbara Brandom from USA. This will allow the reader an objective evaluation with which to make an informed choice about the use of suxamethonium in their practice.

Myoglobinuria in boys with Duchenne muscular dystrophy on corticosteroid therapy.

Myoglobinuria is a recognised complication of Duchenne muscular dystrophy (DMD), but has only once been reported in ambulant boys on corticosteroid therapy [Dubowitz V, Kinali M, Main M, Mercuri E, Muntoni F. Remission of clinical signs in early Duchenne muscular dystrophy on intermittent low-dosage prednisolone therapy. Eur J Paediatr Neurol 2002;6(3):153-9.]. We present three prednisolone-treated boys with myoglobinuria and in two cases this was recurrent. All three showed improved motor performance in response to the introduction of corticosteroids. The greater activity of steroid-treated individuals may place their dystrophin-deficient muscles under greater mechanical stress, predisposing to further muscle fibre damage and consequent myoglobinuria. Families and physicians need to have an increased awareness of this possibility and of the appropriate management of myoglobinuria.

Rhabdomyolysis.

Rhabdomyolysis is a syndrome involving the breakdown of skeletal muscle causing myoglobin and other intracellular proteins and electrolytes to leak into the circulation. The development of rhabdomyolysis is associated with a wide variety of diseases, injuries, medications and toxins. While the exact mechanisms responsible for all the causes are not fully understood, it is clear that muscle damage can occur from direct injury or by metabolic inequalities between energy consumption and energy production. Rhabdomyolysis is diagnosed by elevations in serum creatine phosphokinase (CPK), and while there is no established serum level cut-off, many clinicians use five times the upper limit of normal ( approximately 1000 U/l). Rhabdomyolysis can be complicated by acute renal failure (occurring in 4%-33% of patients), compartment syndrome, cardiac dysrhythmias via electrolyte abnormalities, and disseminated intravascular coagulopathy. The mainstay of treatment is hospitalisation with aggressive intravenous fluid (IVF) resuscitation with the correction/prevention of electrolyte abnormalities. There are additional adjunctive therapies to IVF, such as alkalinisation of the urine with sodium bicarbonate, diuretic therapy or combinations of both; however the lack of large randomised control studies concerning the benefits of these treatments makes it difficult to make strong recommendations for or against their use in the treatment of rhabdomyolysis. Regardless of these controversies, the overall prognosis for rhabdomyolysis is favourable when treated with early and aggressive IVF resuscitation, and full recovery of renal function is common. Irrespective of the cause of rhabdomyolysis the mortality rate may still be as high as 8%. This is a comprehensive review of the pathophysiology, diagnosis, complications and treatment options for rhabdomyolysis.

Exercise-induced cramp, myoglobinuria, and tubular aggregates in phosphoglycerate mutase deficiency.

We report two patients in whom phosphoglycerate mutase (PGAM) deficiency was associated with the triad of exercise-induced cramps, recurrent myoglobinuria, and tubular aggregates in the muscle biopsy. Serum creatine kinase (CK) levels were elevated between attacks of myoglobinuria. Forearm ischemic exercise tests produced subnormal increases of venous lactate. Muscle biopsies showed subsarcolemmal tubular aggregates in type 2 fibers. Muscle PGAM activities were markedly decreased (3% of the normal mean) and molecular genetic studies showed that both patients were homozygous for a described missense mutation (W78X). A review of 15 cases with tubular aggregates in the muscle biopsies from our laboratory and 15 cases with PGAM deficiency described in the literature showed that this clinicopathological triad is highly suggestive of PGAM deficiency.

A case of CPT deficiency, homoplasmic mtDNA mutation and ragged red fibers at muscle biopsy.

A 45-year-old male patient had an episode of acute renal failure with myoglobinuria, myalgias, weakness, and markedly increased serum CK levels. Similar episodes had occurred in the past. Carnitine palmitoyl-transferase II (CPT II) deficiency was documented both biochemically and genetically. Interestingly, muscle biopsy also showed some ragged red fibers (RRF) and complete mitochondrial DNA (mtDNA) sequence disclosed a homoplasmic T3394C point mutation. This mutation is described in Leber's hereditary optic neuropathy (LHON) or in patients with diabetes mellitus.

Peripheral neuropathy, episodic myoglobinuria, and respiratory failure in deficiency of the mitochondrial trifunctional protein.

Mitochondrial trifunctional protein (TFP) deficiency is a rare disorder of the fatty acid beta-oxidation cycle with heterogeneous phenotypes and occurs secondary to either alpha- or beta-subunit mutations. We characterized the neuromyopathic phenotype of TFP deficiency through adolescence or adulthood in 11 patients, 8 with beta-subunit mutations and 3 with alpha-subunit mutations. Two independent clinical features occurred: infantile-onset progressive peripheral neuropathy and episodic exercise-, illness- or fasting-induced rhabdomyolysis accompanied by respiratory failure (in five patients). The combination of episodic rhabdomyolysis and peripheral neuropathy occurred in 10 of the 11 patients. The neuromyopathic phenotype is common in TFP deficiency (11 of 27 families from our cohort). Therefore, this disorder must be considered in the differential diagnosis of progressive peripheral neuropathy with or without episodic myoglobinuria.

Myoglobinuria and COX deficiency in a patient taking cerivastatin and gemfibrozil.

The authors describe a patient who presented with myoglobinuria after starting cerivastatin-gemfibrozil therapy. Muscle histochemistry revealed ragged-red fibers and cytochrome c oxidase negative (COX) fibers, and biochemistry showed a defect of COX activity. Immunoblot analysis showed a 60% reduction of COX I and COX II polypeptides. Cerivastatin myotoxicity might be related to a depletion of essential metabolites needed to anchor COX subunit I to mitochondrial membrane.

A3 adenosine receptor knockout mice are protected against ischemia- and myoglobinuria-induced renal failure.

A(3) adenosine receptor (AR) activation and inhibition worsen and improve, respectively, renal function after ischemia-reperfusion (I/R) injury in rats. We sought to further characterize the role of A(3) ARs in modulating renal function after either I/R or myoglobinuric renal injury. A(3) knockout mice had significantly lower plasma creatinines compared with C57 controls 24 h after I/R or myoglobinuric renal injury. C57 control mice pretreated with the A(3) AR antagonist [3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5 dicarboxylate] or agonist [0.125 mg/kg N(6)-(3-iodobenzyl)-N-methyl-5'-carbamoyladenosine (IB-MECA)] demonstrated improved or worsened renal function, respectively, after I/R or myoglobinuric renal injury. Higher doses of IB-MECA were lethal in C57 mice subjected to renal ischemia. H(1) but not H(2) histamine receptor antagonist prevented death in mice pretreated with IB-MECA before renal ischemia. Improvement in renal function was associated with significantly improved renal histology. In conclusion, preischemic A(3) AR activation (0.125 mg/kg IB-MECA) exacerbated renal I/R injury in mice. Mice lacking A(3) ARs or blocking A(3) ARs in wild-type mice resulted in significant renal protection from ischemic or myoglobinuric renal failure.