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|LETTERS TO EDITOR
|Year : 2019 | Volume
| Issue : 4 | Page : 1152-1153
Proximal Myopathy as a Presenting Manifestation of Wilson's Disease
Hansashree Padmanabha1, Aruna Sethuraman2, Gosala RK Sarma1
1 Department of Neurology, St Johns Medical College and Hospital, Bengaluru, Karnataka, India
2 Department of Pediatrics, St Johns Medical College and Hospital, Bengaluru, Karnataka, India
|Date of Web Publication||10-Sep-2019|
Dr. Aruna Sethuraman
Department of Pediatrics, St Johns Medical College and Hospital, Bengaluru - 560 034, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Padmanabha H, Sethuraman A, Sarma GR. Proximal Myopathy as a Presenting Manifestation of Wilson's Disease. Neurol India 2019;67:1152-3
Wilson's disease (WD) is an autosomal recessively inherited neurometabolic disorder due to mutations in ATP7B gene leading to impaired copper metabolism and excessive copper accumulation in the liver, brain and eyes. The presenting manifestations are myriad and predominantly have hepatic or central nervous system (CNS) involvement. Proximal myopathy as a presenting manifestation of WD is rare and not well documented. The authors share an experience of an 8-year-old boy diagnosed as WD presenting with proximal weakness.
An 8-year-old boy had presented with progressive difficulty in running and climbing stairs for past 3 months. Subsequently, within a month he developed jaundice and abdominal distension associated with facial puffiness. On examination, he had normal anthropometry, icterus, pedal oedema and firm hepatomegaly with shifting dullness. Neurologically, he had hip extensor and abductor predominant proximal weakness (MRC Grade 3/5) with preserved reflexes and sensations. He was second born to a third-degree consanguineous couple with unremarkable family history. Work up for proximal weakness revealed normal creatine phosphokinase 89 IU/L, normal nerve conduction parameters and myopathic interference pattern in electromyography of quadriceps femoris. In view of normal electrolytes, arterial blood gas (ABG) and urine pH, proximal renal tubular acidosis (RTA) was ruled out. Parents refused the muscle biopsy. Additional investigations revealed mild transaminitis (aspartate aminotransferase of 122 U/L, alanine aminotransferase of 85 U/L), hypoalbuminaemia, coagulopathy, low ceruloplasmin 0.024 g/L (N 0.2–0.5 g/L) and high 24 h urinary copper of 554 μg/24 h. Slit-lamp examination showed the Kayser–Fleischer (KF) ring. Hence, a final diagnosis of WD with proximal myopathy was considered. He has been initiated on oral penicillamine at 20 mg/kg/day, oral zinc 25 mg thrice daily along with restriction of copper-rich diet. Trientine could not be given due to its unavailability in the country.
The involvement of musculoskeletal system in WD is uncommon. Few manifestations are described including arthralgia, arthritis, hypokalemic proximal weakness, rarely rhabdomyolysis and spasmodic muscle cramps., The largest series by Taly et al. had reported only 22 of 282 (0.07%) patients with WD manifesting with proximal myopathy. Experimentally copper accumulation in skeletal muscles is known to cause signs of muscle degeneration as early as 3 days. The probable mechanism of myopathy in WD could be due to intracellular copper accumulation in the skeletal muscles leading to oxidative stress, free radical formation, secondary mitochondrial dysfunction and cell death. Presently, 3 months into chelation the proximal weakness has substantially resolved, suggesting the direct effect of copper. The authors described this case to highlight that proximal myopathy though rare, can be a presenting manifestation of WD usually associated with evidence of hepatic or CNS involvement. Absence of calf muscle hypertrophy, normal creatine phosphokinase, normal nerve conduction studies and KF ring on slit-lamp examination might be additional clues to clinch the diagnosis.
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| » References|| |
Taly AB, Meenakshi-Sundaram S, Sinha S, Swamy HS, Arunodaya GR. Wilson disease: Description of 282 patients evaluated over 3 decades. Medicine (Baltimore) 2007;86:112-21.
Rosen JM, Kuntz N, Melin-Aldana H, Bass LM. Spasmodic muscle cramps and weakness as presenting symptoms in Wilson disease. Pediatrics 2013;132:e1039-42.
Geissinger HD, Robinson GA. Copper-induced skeletal myopathy in rabbits. Can J Comp Med 1981;45:97-102.