A
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A 1 year old boy presents with motor delay since birth. Examination shows joint contractures, hypotonia & diffuse weakness. Intelligence is normal. Serum CK is elevated at 950. MRI shows increased T2 signal in CNS white matter. Answer: Laminin-α2 & α-Dystroglycan Biopsy shows no active myopathy but many small immature muscle fibers. Diagnosis: Congenital Muscular Dystrophy |
B
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A 20 year old male noted difficulty climbing stairs. His mother has a history of malignant hyperthermia during surgery. Examination shows symmetric proximal weakness. Serum CK is 500. EMG is myopathic. Answer: NADH and ATPase Biopsy shows central cores & all type I fibers. Diagnosis: Central Core Disease |
C
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A 20 year old male is admitted to the cardiac service for repeated syncope. His mother died suddenly several years ago. Exam shows scapular winging, symmetric weakness in the biceps and triceps, and elbow contractures. Biopsy shows no active myopathy. Serum CK is 426. EKG shows bradycardia and atrial arrhythmias. Answer: Emerin Diagnosis: Emery-Dreifuss Muscular Dystrophy |
D
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A 5 year old male is evaluated for falling and slow running. He was normal until 3 years of age. Examination shows large calves, proximal weakness, waddling gait and difficulty arising from the floor. Serum CK is 11,000. Answer: Dystrophin Biopsy shows prominent muscle fiber necrosis & regeneration. Diagnosis: Duchenne Muscular Dystrophy |
E
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A 36 year old female is evaluated for slowly progressive fatigue and weakness. The patient's mother had similar problems. Examination shows large calves and proximal weakness. Serum CK is 700. Answer: ATPase: Internal nuclei are mostly in type 2 fibers. Pyknotic nuclear clumps are common. Diagnosis: Myotonic Dystrophy, Type 2 |
F
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A 36 year old mentally retarded Afro-American female is evaluated for weakness and excessive sleepiness. The patient's mother had milder weakness, but died suddenly in her 40's. Examination shows distal > proximal weakness, especially with grip. Serum CK is normal. Answer: Acid phosphatase: Granules in muscle fiber cytoplasm. EMG shows myotonia Diagnosis: Myotonic Dystrophy, Type 1 |