اميوتروفيك لترال اسكلروزيس يا بيماري كندي: گزارش يك مورد بيماري

AMYOTROPHIC LATERAL SCLEROSIS OR KENNEDYʹʹS DISEASE: A CASE REPORT OF A PATIENT WITH THREE YEARS OF MISDIAGNOSIS

بيماري كندي (Kennedy disease) يا اتروفي عضلاني نخاعي و بولبار (BSMA) يك اختلال وابسته به جنس مغلوب با شروع در بزرگسالي است كه در اثر تكرار تري نوكليوتيد سيتوزين آدنين - گوانين (CAG) ايجاد مي‌شود. به علت هم پوشاني علايم اين بيماري با ساير اختلالات نوروماسكولر نظير اميوتروفيك لترال اسكلروزيس (ALS) يا اتروفي عضلاني نخاعي (SMA)، بيماري كندي گاهي اوقات اشتباه تشخيص داده شده يا مورد توجه قرار نمي‌گيرد. در اين گزارش آقاي 56 ساله‌اي با تشخيص بيماري كندي معرفي مي‌شود كه به مدت سه سال با تشخيص ALS تحت درمان بوده است.

Kennedyʹs Disease (KD) Bulbar and spinal muscular atrophy (BSMA) is an adult onset, X-linked, recessive disorder caused by expansion of a polymorphic CAG tandem repeat. Because Kennedy’s clinical symptoms overlap with some other neuromuscular disorders such as amyotrophic lateral sclerosis (ALS) or spinal muscular atrophies, KD sometimes is misdiagnosed or left unnoticed. Here we describe a case of Kennedy’s disease confirmed by genetic testing who had been diagnosed and treated with ALS for three years. We describe a 56-year-old man presented with progressive onset of lower limbs muscular atrophy, weakness, and fasciculations since five years ago. He also complained of instability and fatigue when walking. Since three years ago, he had difficulty in swallowing and talking. He denied any sensory symptoms and sphincter disturbances. On examination at disease beginning he had normal mental status, bilateral facial palsy, tongue atrophy and fasciculation. The patient had lower limb muscle atrophy with mild weakness. The deep tendon reflexes all were depressed and the plantar responses were abolished. There were no sensory and cerebellar signs. Neuroimaging didnʹt show any significant pathology. Electrodiagnostic examination (EDX) revealed neurogenic pattern with low compound muscle action potentials (CMAP) and acute and chronic denervation pattern in tested muscles, so the patient diagnosed with ALS and treatment started with Riluzole, six months ago we visited him again with new onset sensory symptoms of face and limb parenthesis. Sensory examination revealed mild impairment of pinprick and thermal senses at limbs although senses of vibration and joint position were normal. He had also perioral and facial fasciculations. Since patientʹs signs and symptoms progression was gradual with developing of sensory findings we questioned the initial diagnosis and reevaluate it later on, EDX study showed decreased lower extremities CMAP with absent F-wave and H-reflects. All sensory parameters were near absent. Genetic studies revealed an increased CAG repeat number (50 normal up to 34), confirming the diagnosis of Kennedy disease. KD is the most common disease which is confused with ALS and recognition of KD is important because its prognosis, natural history, family testing, and management is different from ALS so it is necessary to rule out KD in suspected male cases of ALS. Keywords: Amytrophic lateral sclerosis (ALS), Kennedy’s Disease (KD)