Rhabdomyolysis: Review of the literature

Rhabdomyolysis is a serious and potentially life threatening condition. Although consensus criteria for rhabdomyolysis is lacking, a reasonable definition is elevation of serum creatine kinase activity of at least 10 times the upper limit of normal followed by a rapid decrease of the sCK level to (near) normal values. The clinical presentation can vary widely, classical features are myalgia, weakness and pigmenturia. However, this classic triad is seen in less than 10% of patients. Acute renal failure due to acute tubular necrosis as a result of mechanical obstruction by myoglobin is the most common complication, in particular if sCK is >16.000 IU/l, which may be as high as 100,000 IU/l. Mortality rate is approximately 10% and significantly higher in patients with acute renal failure. Timely recognition of rhabdomyolysis is key for treatment. In the acute phase, treatment should be aimed at preserving renal function, resolving compartment syndrome, restoring metabolic derangements, and volume replacement. Most patients experience only one episode of rhabdomyolysis, mostly by substance abuse, medication, trauma or epileptic seizures. In case of recurrent rhabdomyolysis, a history of exercise intolerance or a positive family history for neuromuscular disorders, further investigations are needed to identify the underlying, often genetic, disorder. We propose a diagnostic algorithm for use in clinical practice.     

Statin myopathy

Many different classes of medications can cause toxic myopathy. One of the most frequently implicated classes is the statins. Statin myotoxicity ranges from asymptomatic creatine kinase elevations or myalgias to muscle necrosis and fatal rhabdomyolysis. Statins may also cause an autoimmune myopathy requiring immunosuppressive treatment. The mechanisms of statin myotoxicity are unclear. If unrecognized in its early manifestations, complications from continued statin therapy may lead to rhabdomyolysis and death. Risk factors for myotoxicity include concomitant medication use and medical conditions, and the patient’s underlying genetic constitution. We review these considerations along with the recommended evaluation and treatment for patients presenting with statin myotoxicity.     

First presentation of LPIN1 acute rhabdomyolysis in adolescence and adulthood

LPIN1 mutations are a known common cause of autosomal recessive, recurrent and life-threatening acute rhabdomyolysis of childhood-onset. The first episode of rhabdomyolysis usually happens in nearly all cases before the age of 5 and death is observed in 1/3 of patients. Here we present two cases of acute rhabdomyolysis with a milder phenotype caused by LPIN1 mutation presenting in adolescence (11 years old) and adulthood (40 years old) after Parvovirus infection and metabolic stress, respectively. In our opinion, the mutation types, epigenetic factors, the environment exposition to triggers or the existence of proteins with a similar structure of LPIN1, may have a role in modulating the onset of rhabdomyolysis. LPIN1 should be included on a panel of genes analysed in the investigation of adult individuals with rhabdomyolysis. Metabolic and viral stressors should be included in the list of possible rhabdomyolysis precipitant.     

Malignant McLeod myopathy

Mild myopathy is a common manifestation of the X-linked McLeod neuroacanthocytosis syndrome. We present a patient with McLeod syndrome and a primarily subclinical myopathy, who developed severe rhabdomyolysis with renal insufficiency after a prolonged period of excessive motor restlessness due to an agitated psychotic state and a single dose of clozapine. Other possible causes for rhabdomyolysis such as prolonged immobility, trauma, hyperthermia, generalized seizures, toxin exposure, or metabolic changes were excluded. Clinical course was favorable, with persistent slight elevation of serum creatine kinase levels caused by the underlying myopathy. Our findings suggest that McLeod myopathy is a predisposing factor for severe rhabdomyolysis. This possibly life-threatening condition should be added to the clinical spectrum of McLeod syndrome, and serum creatine kinase levels should be carefully monitored in patients with this syndrome, particularly if a hyperkinetic movement disorder is present or neuroleptic medication is used.     

Thyroid replacement therapy in Down's syndrome with hypothyroidism.

Three elderly subjects with Down's syndrome and biochemical evidence of hypothyroidism were investigated before and after four months of thyroid replacement treatment. The patients' appearance was demonstrated by photographs and the biochemical thyroid values and the intellectual performance were assessed. The appearance before treatment varied from a florid myxoedematous appearance to a state without features indicating myxoedema. Thyroid replacement therapy was given in usual dose and the biochemical response was similar to that seen in normal subjects. The intellectual performance improved little or not at all. The characteristic discomfort usually associated with hypothyroidism was very pronounced in one case and disappeared totally during treatment. It is concluded that the diagnosis of hypothyroidism in elderly subjects with Down's syndrome can be very difficult when based on appearance and history alone and biochemical thyroid tests are often necessary. The patients should be treated with replacement therapy just as other patients suffering from hypothyroidism.     

Increased frequency of rhabdomyolysis in familial dysautonomia

Introduction:Familial dysautonomia (FD; OMIM # 223900) is an autosomal recessive disease with features of impaired pain and temperature perception and lack of functional muscle spindles. After 3 FD patients presented with rhabdomyolysis in a short time span, we aimed to determine the frequency of rhabdomyolysis is this population. Methods: This study was a retrospective chart review of 665 FD patients. Results: Eight patients had at least 1 episode of rhabdomyolysis. Two patients had 2 episodes. The average incidence of rhabdomyolysis in FD was 7.5 per 10,000 person‐years. By comparison, the average incidence with statins has been reported to be 0.44 per 10,000 person‐years. Mean maximum creatine kinase (CK) level was 32,714 ± 64,749 U/L. Three patients had hip magnetic resonance imaging showing gluteal hyperintensities. Conclusions: Patients with FD have an increased incidence of rhabdomyolysis. We hypothesize that this may result from a combination of absent functional muscle spindles and muscle mitochondrial abnormalities. Muscle Nerve, 2015     

Statin-associated cerebellar ataxia. A Brazilian case series

BackgroundDrug-induced cerebellar ataxias (DICA) represent an important group of secondary cerebellar ataxias. Herein, we reported a case series of progressive cerebellar ataxia induced by HMG-CoA reductase inhibitors (statins).MethodsObservational study with a Brazilian case series of patients with cerebellar ataxia due to statins use.ResultsWe described four patients with cerebellar ataxia, predominantly gait ataxia, due to statins use. Mean age was 67.5 years old, predominantly male, with several comorbidities, such as dyslipidemia, diabetes mellitus, hypertension, and myocardial revascularization. After statin withdrawal, and treatment with coenzyme Q10 in some patients, progressive improvement of gait ataxia was observed.DiscussionWe presented a case series of four patients with cerebellar ataxia due to statins use, which represents a new rare side-effect of statins, probably related to coenzyme Q10 deficiency.     

Induction of the C-terminal proteolytic cleavage of AβPP by statins

Statins are drugs commonly used to inhibit cholesterol synthesis, with the goal of reducing vascular diseases such as myocardial infarction and stroke. Statins have also been suggested as a therapeutic option for Alzheimer's disease (AD), although their benefit in AD remains controversial. We have previously shown that the intracellular C-terminal cleavage of the amyloid-β protein precursor (AβPP) is a major contributor to the neuronal toxicity seen in AD, and that this cleavage can be induced by amyloid-β. We now report that certain brain permeable statins are also able to induce the C-terminal cleavage of AβPP and associated cell death, whereas other statins do not. This statin effect on AβPP exceeded the effects of all other FDA-approved drugs in a library composed of these compounds, suggesting that this effect on AβPP cleavage is unique to a subset of the statins. Furthermore, the greatest effect occurred with cerivastatin, which has previously been shown to be the statin associated with the greatest risk of rhabdomyolysis. These results may have implications for the choice of which statins to evaluate in AD therapeutic trials; furthermore, the results may inform statin choice in individuals who are at high risk for the development of AD, such as those with an apolipoprotein E ε4 allele.     

Hypothyroid myopathy with a strikingly elevated serum creatine kinase level

Although serum creatine kinase (CK) levels are frequently modestly elevated in patients with hypothyroid myopathy, elevations in serum CK to the levels usually seen in inflammatory myopathies or dystrophies are rare. We report a patient with progressive proximal weakness and a serum CK level of over 29,000 IU/L, in whom subsequent laboratory evaluation identified profound hypothyroidism. Thyroid hormone replacement therapy resulted in resolution of clinical symptoms and a marked reduction in the serum CK level. Such a high serum CK level in a patient with hypothyroidism underscores the importance of assessing thyroid function in patients with weakness, regardless of serum CK levels, even when systemic symptoms and signs of hypothyroidism are minimal or absent.     

Idiopathic rhabdomyolysis in children

Idiopathic rhabdomyolysis (myoglobinuria) in children differs clinically from adult cases. The childhood form generally presents with fewer attacks of greater severity and without an exertional precipitant. The mortality rate in children is high. Two fatal cases, in patients ages 3 years and 8 months and 9 months respectively, are reported. The second case is the youngest patient reported to have died with rhabdomyolysis. Both children had weakness of a subacute but relentlessly progressive nature. Weakness of the respiratory muscles led to death in each case after a course of several weeks. Myoglobinuria was never a prominent feature of the illness.The pathologic changes in the skeletal muscles of both cases were similar and consisted of widespread necrosis of individual muscle fibers randomly distributed among intact fibers. There was no evidence of inflammatory changes. Electron microscopic study of the muscle of Case 1 showed the affected fibers to be in various stages of necrosis. Phagocytosis and regeneration were also seen. These morphologic alterations of muscle are similar to those seen in adult cases of rhabdomyolysis, despite the differences in the clinical manifestations and in the prognosis.     

Multiple cerebral infarctions in a patient with Churg-Strauss syndrome

Neurological manifestation of Churg-Strauss syndrome (CSS) is common and usually consists of peripheral neuropathy due to small-vessel vasculitis, while cerebral manifestation is less frequent. We report the case of a 77-year-old woman with multiple cerebral infarctions and hypereosinophilia. The presence of hypereosinophilia, asthma, sinusitis and vasculitis led to the diagnosis of CSS. As cerebral infarctions occurred monophasically and an elevation of heart enzymes was present, we assumed cardiac involvement and multiple cerebral infarctions due to cardiac embolism. Treatment with high-dose IV methylprednisone and cyclophosphamide pulses led to significant improvement. This case illustrates multiple cerebral infarctions in CSS. CSS should always be considered in patients with hypereosinophilia and stroke.     

Cytoskeletal myotoxicity from simvastatin and colchicine

We report the case of a 79-year-old man with mild chronic renal failure who developed severe rhabdomyolysis after combined exposure to simvastatin and colchicine. Colchicine induces myopathy through disruption of microtubular function with subsequent vacuolization and pseudomyelinic body accumulation. Statin therapy is associated with myonecrosis, membranous myeloid bodies, and vacuolization, presumably as a function of impaired isoprenoid metabolism. Vesicle trafficking requires small G-protein prenylation and statins can disrupt cytoskeletal integrity. We propose that synergistic cytoskeletal myotoxicity may account for the extreme elevation of serum creatine kinase not previously reported in pure colchicine myopathy.     

Association of MS with thyroid disorders.

A controlled prospective study was conducted to determine whether thyroid disorders are present with increased frequency in patients with MS. We found that thyroid disorders were at least three times more common in women with MS than in female controls. This was accounted for mainly by the prevalence of hypothyroidism among the female MS patients. Because hypothyroidism is usually due to Hashimoto's thyroiditis, its association with MS may support the hypothesis of autoimmune pathogenesis for MS. Our findings might have therapeutic implications because interferon treatment can induce antithyroid antibodies and thyroiditis.     

Delayed chorea after recovery from a symmetric parkinsonian syndrome due to striatal myelinolysis

Extrapontine myelinolysis (EPM) is rare and usually results from osmotic stress due to inappropriate correction of electrolyte disturbances. Parkinsonism is a relatively common manifestation of EPM, seen in 60% of patients. Dopaminergic therapy leads to good recovery in many patients. Delayed extrapyramidal manifestations, including hyperkinetic movement disorders such as chorea or dystonia, are postulated to result from aberrant neuronal regeneration or denervation supersensitivity following the initial osmotic insult. We present a patient with a symmetric parkinsonian syndrome due to EPM involving the striatum who made a good recovery with levodopa therapy, only to develop chorea five months later. The possible mechanisms underlying the genesis of these movement disorders in EPM is discussed.     

Congenital Muscular Dystrophy Presenting with Respiratory Failure

Respiratory failure is an unusual initial manifestation of congenital muscular dystrophy. The authors describe a case of congenital muscular dystrophy in a patient presenting with rhabdomyolysis at birth. Despite an initially poor prognosis, aggressive respiratory therapy during the neonatal period permitted normal subsequent development. The muscular dystrophy predominantly involved the respiratory muscles.     

Statin myotoxicity: A review of genetic susceptibility factors

The 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors (statins) are among the most common medications prescribed worldwide, but their efficacy and toxicity vary between individuals. One of the major factors contributing to intolerance and non-compliance are the muscle side-effects, which range from mild myalgia through to severe life-threatening rhabdomyolysis. One way to address this is pharmacogenomic screening, which aims to individualize therapy to maximize efficacy whilst avoiding toxicity. Genes encoding proteins involved in the metabolism of statins as well as genes known to cause inherited muscle disorders have been investigated. To-date only polymorphisms in the SLCO1B1 gene, which encodes the protein responsible for hepatic uptake of statins, and the COQ2 gene, important in the synthesis of coenzyme Q10, have been validated as being strongly associated with statin-induced myopathy. The aim of this review is to summarize studies investigating genetic factors predisposing to statin myopathy and myalgia, as the first step towards pharmacogenomic screening to identify at risk individuals.     

Acute pediatric rhabdomyolysis

Rhabdomyolysis is a relatively common condition that may occur intermittently in chronic and inflammatory myopathy, muscular dystrophy, and metabolic myopathy. Rhabdomyolysis can also present acutely in otherwise healthy individuals. The list of etiologies for acute muscle cell lysis is enormous, with new causes described yearly. Series on acute pediatric rhabdomyolysis have not yet been published. This article describes a retrospective review of children admitted to the authors' institution during an 8-year period in whom rhabdomyolysis was recognized as a complication during their hospital stay. Patients with intermittent or relapsing rhabdomyolysis were excluded. Nineteen children were identified. Trauma (five cases), nonketotic hyperosmolar coma (two cases), viral myositis (two cases), dystonia (two cases), and malignant hyperthermia-related conditions (two cases) were the most common causes of rhabdomyolysis. Acute renal failure was the most frequent complication, occurring in 42% of cases. The mean age of renal failure patients was 13.9 years, compared to 8 years for non-renal failure children. Careful assessment of the initial urinalysis would have suggested a diagnosis of rhabdomyolysis in 9 of 16 patients tested.     

Posterior reversible encephalopathy syndrome in IgA vasculitis: Neuroimaging of a 14-year-old child

IgA vasculitis (IgAV) is a leukocytoclastic vasculitis and characterized by involvement of small vessels in skin, gastrointestinal system, joints, kidneys, and less frequently other organs. It is the commonest vasculitis in childhood and etiology is not completely known. Neurological manifestations of IgAV are very rare and usually seen in patients with severe hypertension or as an uncommon feature such as peripheral neuropathy. Posterior reversible encephalopathy syndrome (PRES) is a clinic-radiologic entity characterized with temporary vasogenic edema developing typically in posterior circulation of the brain and has been reported as a rare manifestation of IgAV. In this paper, a PRES case of 14-year-old male with IgAV is reported and etiopathogenesis was discussed with literature. Diagnosis was made by magnetic resonance imaging because of the existence of neurological symptoms (headache and visual loss) during the course of disease. His radiological findings have resolved with therapy. Although neurological involvement is a rare manifestation in IgAV, we recommend magnetic resonance imaging in such patients for diagnosis and evaluation of complications.     

Trifunctional enzyme deficiency: Adult presentation of a usually fatal β-oxidation defect

Disorders of mitochondrial fatty acid oxidation are a common cause of exercise-induced rhabdomyolysis and myoglobinuria. We report three adult patients from a family with symptoms of recurrent exercise-induced rhabdomylysis. This presentation closely resembles adult-type carnitine palmitoyltransferase II deficiency except that these patients had an associated peripheral neuropathy. Investigation of fatty acid oxidation in the patients revealed a deficiencyof the mitochondrial trifunctional enzyme of β-oxidation, a newly described fatty acid oxidation disorder with multiorgan involvement and a usually fatal outcome in early childhood. Our cases therefore represent a new phenotype of the disease, which is characterized by recurrent rhabdomyolysis and peripheral neuropathy, but without involvement of other organs, and which is associated with prolonged survival beyond the fourth decade. A low-fat/high-carbohydrate diet proved bneficial in one of the patients, drastically reducing the frequency of rhabdomyloytic episodes. Our findings suggest that mitochondrial trifnctional enzyme deficiency should be considered in patients with recurrent eipsodes of myoglobinuria and peripheral neuropathy presenting in later life.     

Statin-associated myopathy and its exacerbation with exercise

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are a common and effective treatment for hypercholesterolemia, with a low overall rate of side-effects. The most common complication is some degree of skeletal muscle myopathy, ranging from painless serum creatine kinase elevations to rhabdomyolysis. Unfortunately, the likelihood and/or severity of complications increases with the combination of statin treatment and physical activity. The specific pathways that mediate statin-associated myopathy are unclear, and research directly addressing the exacerbation with exercise is limited. Potential mechanisms include the induction of skeletal muscle fiber apoptosis, alterations in ubiquitin-proteasome pathway activity, mitochondrial dysfunction, and terpenoid depletion. In this review we provide an overview of research that specifically addresses the combination of statin-associated myopathy and physical activity and highlight some deficiencies in the available literature, as well as future directions for this important subset of statin-associated myopathy.