Abstract
There are few reports about the persistent elevation of serum CFK values and pathologic changes of peripheral nerve in periodic paralysis.
The patient had been in good health until age 12, when he suddenly felt a severe weakness of lower limbs and found himself unable to stand up and walk for a few days, but this episode disappeared spontaneously.
He was admitted to the hospital 7 months after the onset. The physical examination was not remarkable. The neurological examination revealed hypoactive patellar reflex.
The values of serum CPK were markedly and persistently elevated. There were no abnormalities in the values of serum electrolytes, GOT, LDH, lactate, pyruvate, renin, aldosterone and blood gas. Thyroid function was normal. The serum potassium levels were found to decrease to 3.4 mEq/1. during the attack. The potassium in erythrocytes was low compared to normal values, and became lower during the attack.
We examined biopsy samples of the peroneus brevis muscle and the sural nerve histologically. The muscle demonstrated hypotrophic type I fibers and angular fibers. Fiber necrosis, vacuolation and cell infiltration did not exist. On electron microscopy, a slight dilatation of t-tubules and some membrane-limited vacuoles communicated with several t-tubules were the additional findings. The sural nerve showed a slight decrease of large size myelinated, fibers in semi-thin transverse sections. Electron microscopic findings were the swelling of cytoplasma in some Schwann cells surrounding myelinated fibers and denuded axons.
Frequency of the attacks decreased gradually with the oral administration of potassium chloride and acetazolamide, though this case was supposed to be an atypical type of hypokalemic periodic paralysis. Moreover, the values of serum CPK were normalized by the steroid therapy (prednisolone 1 mg/kg) and subsequently the attack disappeared.
