Myotonia in colchicine myoneuropathy

Myoedema: a forgotten sign in acute colchicine myopathy

Colchicine myopathy typically presents acutely to subacutely with progressive limb weakness. The patients may not be on high doses of colchicine but almost always have acute kidney injury. Dehydration from colchicine-induced diarrhoea is often a precipitating factor. The concomitant neurotoxicity may produce mild sensory complaints. This combination of acute neurological symptoms preceded by diarrhoea prompts the diagnosis of Guillain-Barre syndrome (GBS). The absence of cranial nerve deficits, raised creatine kinase and myotonic discharges on electromyogram may help in differentiating this condition from GBS. We describe a clinical sign, myoedema - a mounding phenomenon of muscle that is elicited by percussion and resolves when the patient recovers. It aids in the bedside diagnosis of acute colchicine myopathy as well as distinguish it from other more common causes of acute flaccid paralysis. We also discuss the possible mechanism of colchicine toxicity and the mounding phenomenon.

Non-dystrophic myotonia: 2-year clinical and patient reported outcomes

INTRODUCTION/AIMS

Consistency of differences between non-dystrophic myotonias over time measured by standardized clinical/patient-reported outcomes is lacking. Evaluation of longitudinal data could establish clinically relevant endpoints for future research.

METHODS

Data from prospective observational study of 95 definite/clinically suspected non-dystrophic myotonia participants (six sites in the United States, United Kingdom, and Canada) between March 2006 and March 2009 were analyzed. Outcomes included: standardized symptom interview/exam, Short Form-36, Individualized Neuromuscular Quality of Life (INQoL), electrophysiological short/prolonged exercise tests, manual muscle testing, quantitative grip strength, modified get-up-and-go test. Patterns were assigned as described by Fournier et al. Comparisons were restricted to confirmed sodium channelopathies (SCN4A, baseline, year 1, year 2: n = 34, 19, 13), chloride channelopathies (CLCN1, n = 32, 26, 18), and myotonic dystrophy type 2 (DM2, n = 9, 6, 2).

RESULTS

Muscle stiffness was the most frequent symptom over time (54.7%-64.7%). Eyelid myotonia and paradoxical handgrip/eyelid myotonia were more frequent in SCN4A. Grip strength and combined manual muscle testing remained stable. Modified get-up-and-go showed less warm up in SCN4A but remained stable. Median post short exercise decrement was stable, except for SCN4A (baseline to year 2 decrement difference 16.6% [Q1, Q3: 9.5, 39.2]). Fournier patterns type 2 (CLCN1) and 1 (SCN4A) were most specific; 40.4% of participants had a change in pattern over time. INQoL showed higher impact for SCN4A and DM2 with scores stable over time.

DISCUSSION

Symptom frequency and clinical outcome assessments were stable with defined variability in myotonia measures supporting trial designs like cross over or combined n-of-1 as important for rare disorders.

Colchicine-Induced Acute Myopathy: Case Study From Saudi Arabia

Colchicine-induced myopathy has been described in patients with chronic renal failure and patients who are using a concomitant drug like a statin. However, pure myopathy caused by colchicine has never been reported in Saudi Arabia. A 64-year-old patient received colchicine for his gout arthritis disease and developed upper and lower limb weakness. He had a proximal weakness, and his muscle enzymes were very high. Furthermore, the needle electromyography (EMG) examination showed abundant fibrillations, myotonic discharges, and myopathic motor units. Two weeks after colchicine cessation, his weakness improved dramatically with normalization of creatine kinase (CK) and disappearance of myotonic discharges in the repeated EMG. This is the first case in Saudi Arabia that showed colchicine-induced myositis. The local clinicians' community needs to be aware of this rare side effect, as clinical suspicion is the most important diagnostic clue and the only effective treatment is the termination of colchicine.

Colchicine-induced rhabdomyolysis: a review of 83 cases

A 74-year-old man with medical history significant for atrial fibrillation, hyperlipidaemia and coronary artery disease on atorvastatin presented to the emergency department with profound weakness. The patient reports he first noticed his weakness 4 weeks after starting colchicine, prescribed for recurrent pericarditis with pericardial effusion, a complication following recent coronary artery bypass grafting. The patient was also on prednisone therapy for presumed post-pericardiotomy syndrome. The weakness involved all four limbs but was more notable in the lower extremities, with preserved sensation and tenderness to palpation. Labs showed an elevated creatinine phosphokinase and serum creatinine consistent with rhabdomyolysis. Discontinuation of the offending medications, including colchicine and atorvastatin, as well as intravenous fluid resuscitation with physical rehabilitation, led to improvement in the patient's symptoms. He was eventually discharged to a rehabilitation facility to continue physical therapy.

Efficacy and safety of gout flare prophylaxis and therapy use in people with chronic kidney disease: a Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN)-initiated literature review

Gout flare prophylaxis and therapy use in people with underlying chronic kidney disease (CKD) is challenging, given limited treatment options and risk of worsening renal function with inappropriate treatment dosing. This literature review aimed to describe the current literature on the efficacy and safety of gout flare prophylaxis and therapy use in people with CKD stages 3-5. A literature search via PubMed, the Cochrane Library, and EMBASE was performed from 1 January 1959 to 31 January 2018. Inclusion criteria were studies with people with gout and renal impairment (i.e. estimated glomerular filtration rate (eGFR) or creatinine clearance (CrCl) < 60 ml/min/1.73 m²), and with exposure to colchicine, interleukin-1 inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs), and glucocorticoids. All study designs were included. A total of 33 studies with efficacy and/or safety analysis stratified by renal function were reviewed-colchicine (n = 20), anakinra (n = 7), canakinumab (n = 1), NSAIDs (n = 3), and glucocorticoids (n = 2). A total of 58 studies reported these primary outcomes without renal function stratification-colchicine (n = 29), anakinra (n = 10), canakinumab (n = 6), rilonacept (n = 2), NSAIDs (n = 1), and glucocorticoids (n = 10). Most clinical trials excluded study participants with severe CKD (i.e. eGFR or CrCl of < 30 mL/min/1.73 m²). Information on the efficacy and safety outcomes of gout flare prophylaxis and therapy use stratified by renal function is lacking. Clinical trial results cannot be extrapolated for those with advanced CKD. Where possible, current and future gout flare studies should include patients with CKD and with study outcomes reported based on renal function and using standardised gout flare definition.

Guidelines on clinical presentation and management of nondystrophic myotonias

The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.

Toxic Myopathies

PURPOSE OF REVIEW

This article reviews the pathogenesis, clinical features, and management of toxic myopathy related to common medications, critical illness, and illicit substances.

RECENT FINDINGS

Muscle symptoms are common among statin users and are usually reversible after discontinuation of the statin; rarely, however, statins trigger an immune-mediated necrotizing myopathy that persists and requires immunomodulatory therapy. Autoantibodies targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase can distinguish the toxic and immune-mediated forms. Immune checkpoint inhibitors, increasingly used in the treatment of advanced cancer, have recently been associated with the development of inflammatory myositis. A reversible mitochondrial myopathy has long been associated with zidovudine, but recent reports elucidate the risk of myopathy with newer antivirals, such as telbivudine and raltegravir.

SUMMARY

The medications most commonly associated with myopathy include statins, amiodarone, chloroquine, hydroxychloroquine, colchicine, certain antivirals, and corticosteroids, and myopathy can occur with chronic alcoholism. Certain clinical, electrodiagnostic, and histologic features can aid in early recognition. Stopping the use of the offending agent reverses symptoms in most cases, but specific and timely treatment may be required in cases related to agents that trigger immune-mediated muscle injury.

Toxic myopathies

Muscle tissue is highly sensitive to many substances. Early recognition of toxic myopathies is important, because they potentially are reversible on removal of the offending drug or toxin, with greater likelihood of complete resolution the sooner this is achieved. Clinical features range from mild muscle pain and cramps to severe weakness with rhabdomyolysis, renal failure, and even death. The pathogenic bases can be multifactorial. This article reviews some of the common toxic myopathies and their clinical presentation, histopathologic features, and possible underlying cellular mechanisms.

Protracted febrile myalgia syndrome in a kidney transplant recipient with familial Mediterranean fever

Drug-induced toxic myopathy is a complication of familial Mediterranean fever in patients who receive colchicine, especially when combined with cyclosporine. Protracted febrile myalgia syndrome is a severe form of familial Mediterranean fever. A 34-year-old man who had familial Mediterranean fever for > 15 years developed kidney failure because of secondary amyloidosis. He received living-unrelated-donor kidney transplant that functioned normally. He was on colchicine prophylaxis that was continued after transplant, and he received immuno-suppression induction with antithymocyte globulin and maintenance with prednisolone, mycophenolate mofetil, and cyclosporine. After 2 months, he presented with severe myopathy and elevated creatine kinase. Muscle biopsy showed evidence of drug-induced toxic myopathy, most likely caused by cyclosporine in combination with colchicine. Cyclosporine was replaced with sirolimus and colchicine was stopped. Symptoms partially improved and creatine kinase decreased to normal. The prednisolone dosage was reduced gradually to 5 mg daily. At 8 months after transplant, he was readmitted because of severe arthralgia, prolonged fever, pleuritic chest pain, diffuse abdominal pain, purpuric rash, macroscopic hematuria, proteinuria, and diarrhea. The C-reactive protein and erythrocyte sedimentation rate were elevated. The clinical diagnosis was recurrent familial Mediterranean fever presenting as protracted febrile myalgia syndrome. Despite the history of toxic myopathy, he was restarted on colchicine (0.5 mg, twice daily), and colchicine was well tolerated. There was marked improvement of most symptoms within several days. Follow-up 5 years later showed normal kidney graft function and no familial Mediterranean fever activity on colchicine prophylaxis. In summary, familial Mediterranean fever reactivation and protracted febrile myalgia syndrome after kidney transplant may be treated with colchicine and modulation of immunosuppressive therapy.

Non-dystrophic myotonia: prospective study of objective and patient reported outcomes

Non-dystrophic myotonias are rare diseases caused by mutations in skeletal muscle chloride and sodium ion channels with considerable phenotypic overlap between diseases. Few prospective studies have evaluated the sensitivity of symptoms and signs of myotonia in a large cohort of patients. We performed a prospective observational study of 95 participants with definite or clinically suspected non-dystrophic myotonia recruited from six sites in the USA, UK and Canada between March 2006 and March 2009. We used the common infrastructure and data elements provided by the NIH-funded Rare Disease Clinical Research Network. Outcomes included a standardized symptom interview and physical exam; the Short Form-36 and the Individualized Neuromuscular Quality of Life instruments; electrophysiological short and prolonged exercise tests; manual muscle testing; and a modified get-up-and-go test. Thirty-two participants had chloride channel mutations, 34 had sodium channel mutations, nine had myotonic dystrophy type 2, one had myotonic dystrophy type 1, and 17 had no identified mutation. Phenotype comparisons were restricted to those with sodium channel mutations, chloride channel mutations, and myotonic dystrophy type 2. Muscle stiffness was the most prominent symptom overall, seen in 66.7% to 100% of participants. In comparison with chloride channel mutations, participants with sodium mutations had an earlier age of onset of stiffness (5 years versus 10 years), frequent eye closure myotonia (73.5% versus 25%), more impairment on the Individualized Neuromuscular Quality of Life summary score (20.0 versus 9.44), and paradoxical eye closure myotonia (50% versus 0%). Handgrip myotonia was seen in three-quarters of participants, with warm up of myotonia in 75% chloride channel mutations, but also 35.3% of sodium channel mutations. The short exercise test showed ≥10% decrement in the compound muscle action potential amplitude in 59.3% of chloride channel participants compared with 27.6% of sodium channel participants, which increased post-cooling to 57.6% in sodium channel mutations. In evaluation of patients with clinical and electrical myotonia, despite considerable phenotypic overlap, the presence of eye closure myotonia, paradoxical myotonia, and an increase in short exercise test sensitivity post-cooling suggest sodium channel mutations. Outcomes designed to measure stiffness or the electrophysiological correlates of stiffness may prove useful for future clinical trials, regardless of underlying mutation, and include patient-reported stiffness, bedside manoeuvres to evaluate myotonia, muscle specific quality of life instruments and short exercise testing.

Electrodiagnosis of myotonic disorders

Clinical and electrical myotonia is caused by a small group of neuromuscular disorders. This article reviews myotonia and its differential diagnosis. The use of electrodiagnostic testing to evaluate the primary myotonic disorders (myotonic dystrophy and the nondystrophic myotonias) is also discussed.

Colchicine myoneuropathy in chronic renal failure patients with gout (Case Report)

Colchicine myoneuropathy is a rare and often underdiagnosed disease. It often presents as painless subacute muscle weakness. We present a case of painful colchicine myoneuropathy in a 76-year-old man with chronic renal failure and gout. Published work about clinical presentations of colchicine myoneuropathy in gouty arthritis patients are reviewed. During the previous year, the patient had a drug regimen of colchicine 0.5 mg three times per day for a 3 day course each month. He developed bilateral lower leg weakness and severe myalgia. His serum creatinine level was 680.7 micromol/L and creatinine kinase was 959 IU/L on admission. Laboratory findings included decreasing amplitude of motor and sensory nerve conduction velocity and an electromyogram showed small amplitude, short duration polyphasic waves over the right biceps. A muscle biopsy disclosed vacuolar changes in the cytoplasm. These results all supported a diagnosis of colchicine myoneuropathy. After cessation of colchicine, the creatinine kinase level decreased approximately 50% in 6 days, myalgia subsided and his muscle weakness improved gradually over the next 2 weeks.

Drug-induced myopathies

The incidence of drug-induced myopathic disorders is unknown. Estimates depend in part on definitions used. Cholesterol-lowering agents have been singled out as common offenders. However, the large number of available drugs, polypharmacy especially among the elderly, and known risk factors make the incidence of mild muscle disorders likely more common than suspected, but severe myopathies are likely rare. This article considers factors contributing to drug-induced myopathies and reviews examples of offending drugs.

Toxic Myopathies

Muscle tissue is highly sensitive to drugs and toxins because ot its high metabolic activity and potential sites for disruption of energy-producing pathways. Early recognition of toxic myopathies is important, as they potentially are reversible on removal of the offending toxin, with greater likelihood of complete resolution the sooner this is achieved. Clinical features range from mild muscle pain and cramps to severe weakness with rhabdomyolysis, renal failure, and even death. The pathogenic bases can be multifactorial. This article reviews drugs responsible for common types of toxic myopathy and their clinical and histopathologic features and illustrates possible underlying cellular mechanisms.

Colchicine myotoxicity: case reports and literature review

Two of our patients experienced myotoxicity associated with colchicine administration. The first was a 54-year-old woman who was receiving dialysis and came to the emergency department with progressive generalized weakness and vomiting. She recently had taken colchicine for the treatment of gout. Physical examination revealed proximal muscle weakness and tenderness on palpation. Her creatine kinase (CK), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were elevated at 7185, 563, and 541 U/L, respectively. Drug-induced myopathy was suspected and colchicine was discontinued. The patient was discharged after symptom resolution 1 week later. The second patient was an 83-year-old woman with chronic renal insufficiency who came to the hospital with anorexia, diarrhea, and inability to get out of bed due to progressive weakness. Her colchicine dosage recently had been increased for gout management. Physical examination revealed generalized muscle weakness and tenderness on palpation. Her CK, ALT, and AST levels were elevated at 1797, 147, and 172 U/L, respectively. Electromyographic results were consistent with colchicine myopathy. The patient was discharged with minimal residual muscle weakness 1 week after discontinuation of colchicine. A literature search identified 82 documented cases of colchicine-induced myotoxicity. Most patients had a history of proximal weakness and pain with elevated CK, ALT, and AST levels. Onset of symptoms generally occurred days to weeks after initial administration of colchicine at the usual dosage in patients with renal impairment or a change in underlying disease state in those receiving long-term therapy. Muscle toxicity was not necessarily accompanied by gastrointestinal symptoms. Concomitantly administered drugs often were cyclosporine or corticosteroids. Diagnosis may be confirmed by electromyography or muscle biopsy. Colchicine-induced myotoxicity is a rare adverse effect but is well described in the literature. Clinicians should recognize that renal impairment is the primary risk factor for development of colchicine-induced myotoxicity, and that dosage adjustment or alternative therapy may be required.

Electrodiagnostic studies in the management and prognosis of neuromuscular disorders

Prognosis remains a neglected aspect of modern medical care and research, behind diagnosis and treatment. The very term "electrodiagnosis" implies as much. Despite this, much has been published regarding the use and benefit of electrodiagnostic techniques in assessing prognosis and assisting in management of patients after the diagnosis has been established. This information is often hidden or otherwise not emphasized. This review summarizes the literature regarding the use of such techniques for prognosis and management of disorders of lower motor neurons, peripheral nerves, neuromuscular transmission, and muscle.

Colchicine-induced myopathy with myotonia in a patient with chronic renal failure

Although colchicine induced myopathy has been described in patients with chronic renal failure, colchicine induced myopathy with myotonia has been reported very rarely. A 49-year-old man with chronic renal failure was hospitalised for investigation of fatigue, malaise and severe pain in all extremities. He was on colchicine therapy for 5 months. Neurological examination showed mildly decreased sensation in a distal symmetric pattern in lower extremities, moderate proximal limb weakness, hyporeflexia and severe myalgia on palpation. No clinical evidence of myotonia was present. Laboratory studies showed elevated creatine phosphokinase (CK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Electromyographic (EMG) findings were compatible with myopathy and abundant, widespread myotonic discharges were determined. Muscle biopsy was consistent with vacuolar myopathy. After withdrawal of colchicine, CK, LDH, AST and ALT levels were normalised and the symptoms were disappeared gradually. In conclusion, the detection of myopathic motor unit potentials with myotonic discharges on EMG in patients on colchicine therapy is an important finding and it is possible to suggest that this clue may lead to the invasive procedure of muscle biopsy unnecessary.

Colchicine-induced acute myopathy in a patient with concomitant use of simvastatin

Colchicine and 3-hydroxy-3-methy-glutaryl coenzyme A (HMG-CoA) reductase inhibitors are well known to cause myopathy. Myotoxicity is dose-dependent in both drugs; therefore, the onset of symptoms usually takes months or years. We report the case of a patient with chronic renal failure who had been taking simvastatin for 2 years and developed acute weakness 2 weeks after the start of treatment with colchicines for recurrent gout. The electromyography and elevated muscle enzymes indicated that his symptoms were caused by myopathy. When this patient stopped taking both drugs, his weakness resolved rapidly. Acute myopathy induced by combination therapy with colchicines and simvastatin is rare. In patients with chronic renal failure, co-administration of colchicine with simvastatin may accelerate the onset of myopathy because CYP3A4 (part of cytochrome P450) is crucial in the breakdown of both drugs. When adding colchicine to a medication regimen that includes a HMG-CoA reductase inhibitor for patients with renal insufficiency, drugs that are metabolized outside the CYP3A4 system (e.g., fluvastatin and pravastatin) should be selected instead.

Electrodiagnostic approach to the patient with suspected myopathy

Uncovering the cause of a suspected myopathy may be challenging. However, a careful approach starts with utilizing the wealth of available information regarding the clinical and laboratory features of myopathy. Electrodiagnostic testing is then obtained (in most cases). Recognition of the pattern of EMG findings in light of the clinical and laboratory features should narrow the differential diagnosis and dictate the next steps in the evaluation. Histopathologic or molecular studies, or both may follow. Ultimately, this approach usually allows the clinician to make the correct diagnosis.

Acute onset of colchicine myoneuropathy in cardiac transplant recipients: case studies of three patients

Colchicine causes both muscle and peripheral nerve toxicity of subacute onset in patients with renal insufficiency. We report three cardiac transplant recipients, treated with colchicine for cyclosporin A (CyA)-induced gout, who developed acute weakness due to colchicine myoneuropathy. The onset of disabling weakness occurred over a 1-2 week period. All three patients had concomitant renal insufficiency and an elevated serum creatine kinase and two elevated CyA levels at the time of presentation. Electromyography revealed features of myopathy and motor axonal neuropathy in all three patients. Two underwent muscle biopsy which confirmed the presence of sarcoplasmic vacuoles characteristic of colchicine-induced myopathy. All patients rapidly improved with either colchicine dose reduction or drug discontinuation. In conclusion, cardiac transplant recipients treated with CyA and colchicine may be at increased risk of developing colchicine-induced myoneuropathy especially in the setting of concurrent renal insufficiency. In patients with post-transplantation gouty arthritis, other treatment modalities are suggested; and if colchicine is administered, the dose should be reduced, CyA levels should be monitored closely and patients should be assessed for signs of neuromuscular toxicity.