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Título

Progressive muscle weakness and dysphagia in an elderly patient: chloroquine myopathy

RESUMO

Case report: A 70 years-old woman sought medical care due to unintentional weight loss of 10 to 15kg in 2 months. There was progressive weakness, dysphagia and dysphonia. She had been treated for gastric cancer and arthritis and was under the use of chloroquine, nortriptyline, desvenlafaxine and a combined formula of indomethacin, prednisone and famotidine. Neurological examination disclosed generalized muscle wasting and weakness, with marked involvement of proximal, axial and bulbar muscles. CK was elevated. Investigation for paraneoplastic syndrome was normal. She was admitted to our hospital to receive clinical and nutritional care and complete the investigation. The EMG showed increased spontaneous activity at rest and findings consistent with a myopathic pattern. The muscle biopsy showed a vacuolar myopathy with autophagic vacuoles. A hypothesis of toxic myopathy due to chronic chloroquine use was made. Medication was discontinued and, although in intensive care, the patient evolved with multiple clinical complications and death. Discussion: Chloroquine is a drug used worldwide for treatment of malaria, and as an immunomodulator to treat a variety of inflammatory disorders. It has a high affinity to some cellular compartments, resulting in abnormalities of lysosomal function and autophagy, as chloroquine remains sequestered into those organelles after chemical modifications due to the acid pH. The cumulative effect can be deleterious to skeletal muscle, which can have a spectrum of clinical presentations. There is a predilection for axial, proximal limb, bulbar, respiratory, and cardiac muscles. The morbidity is high, even after drug discontinuation, although some patients may improve. In our case, there was a rapid evolution to multiple organ dysfunction with respiratory failure secondary to her severe clinical condition.
Final comments: the skeletal muscle is a highly vascularized tissue and, thus, susceptible to the toxic effects of various substances, including a variety of therapeutic drugs. Although rare, chloroquine myopathy can result in marked morbidity and potential mortality if not accurately and promptly diagnosed. The nonspecific clinical manifestations, specially when occurring in the elderly population, may contribute to a misleading diagnosis. In our patient, the muscle biopsy was a crucial tool to characterize the skeletal muscle involvement and attribute chloroquine toxicity as a preponderant factor in her muscle disease.

Palavras Chave

CHLOROQUINE; MYOPATHY; PROGRESSIVE MUSCLE WEAKNESS

Área

Doenças Neuromusculares