Neurology Clerkships
Case 18  
Author: Eric Kraus, MD
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This is a 39 year-old male who first started having problems in the fifth grade of intermittent weakness. The patient's typical events include arm weakness, difficulty walking, right footdrop, dry mouth, and possibly arrhythmias. His triggers are mostly a high-salt diet, but can include beer, high carbohydrate meals, and extra exercise. Normally, he has mild events every two to three months, lasting 24 to 48 hours, with occasional events that last longer, even some requiring admission to the hospital. In between events, he does not describe any permanent weakness.

The patient presents to the ER today after eating a very large piece of ice cream cake. This is a typical episode, but wishes to be seen while the symptoms are present in case it makes a diagnostic difference.

The work-up to date has included a normal EMG with no evidence of myotonia, a normal muscle biopsy that did not show any deficiencies in myophosphorylase or CPT (Carnitine Palmitoyl Transferase), normal TSH, normal CPK, and negative acetylcholine receptor antibodies.

1. Single kidney.
2. Childhood orthopedic problems in his legs, requiring braces. Left leg smaller than the right.

1. Advil prn

Allergies: None

Family History: Negative for similar disease, and he has one biological daughter who is healthy at age 13.

Social History: Works at a local supermarket. He has a 13-year-old daughter, two adopted children, and one stepson on his wife's side.

BP 132/66   HR  104   T 36.5°C
General: Thin male lying on a stretcher. Speech is fluent and strong. Breathing unlabored.
Mental Status: A + O x 3
HEENT: PERRLA. EOMI. Oropharynx benign with tongue and palate midline. Face has normal strength and sensation.
Motor (Power/Tone/Bulk)
: In the upper extremities 4/5 at the deltoids, 5/5 at the biceps, 4/5 at the right triceps, 4+/5 at the left triceps, 4/5 grip, 4+ interossei, 4/5 supraspinatus, and 3/5 infraspinatus. In the lower extremities, hip flexors 4/5, hip extensors 4/5, abductors 5/5, adductors 4/5, knee flexion 4/5, knee extension 4/5, foot dorsiflexors 4/5, and foot plantar flexion 5/5. Tone was normal in the legs, and there is no evidence of myotonia either to grip or percussion in the hand. His left leg is definitely smaller in bulk, mostly in the calf, and his foot looks much smaller on the left side.
Sensory: Normal.
Reflexes: 1/4 biceps, otherwise absent.
Coordination: Normal considering the weakness.
Gait: Slow. Stiff locked knees. Bilateral foot drop and mild waddle. Holds onto the furniture to prevent falling.
Abnormal Movements: None.
Other Organs: Lungs CTA. Heart RRR.

EKG: Normal.

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