One case of spinal bulbar muscular atrophy misdiagnosed as polymyositis: Case report

Rationale: Spinal bulbar muscular atrophy (SBMA) is a rare X-linked recessive motor neuron degenerative disease. Due to the lack of specificity in its early clinical manifestations, SBMA is easily misdiagnosed. Herein, we present a case in which SBMA was misdiagnosed as polymyositis.

Patient concerns: A 58-year-old patient began to develop symptoms of limb weakness 20 years ago and was admitted to the Second Hospital of Hebei Medical University 10 years ago without special treatment. Two years ago, the above symptoms worsened and he was admitted to Peking Union Medical College Hospital. The patient was misdiagnosed as polymyositis. According to the gene mutation characteristics of SBMA, the patient was diagnosed with SBMA.

Diagnoses: The result of the Kennedy gene test was positive, and the patient was diagnosed with Kennedy disease.

Interventions: After the diagnosis of SBMA, the patient was given symptomatic treatment to alleviate the condition.

Outcomes: Conservative treatment after discharge was requested. It is recommended that patients avoid bucking to prevent complications.

Lessons: This is a case of milder SBMA being misdiagnosed as polymyositis. For patients with weak limbs, the possibility of SBMA should be considered.