Histochemical and Molecular Genetic Study of MELAS and MERRF in Korean Patients

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episode (MELAS) and myoclonic epilepsy and raggedred fibers (MERRF) are rare disorders caused by point mutation of the tRNA gene of the mitochondrial genome. To understand the pathogenetic mechanism of MELAS and MERRF, we studied four patients. Serially sectioned frozen muscle specimens with a battery of histochemical stains were reviewed under light microscope and ultrastructural changes were observed under electron microscope. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed and the tRNA genes were sequenced to confirm mutations. In two patients with MELAS, strongly succinyl dehydrogenase positive blood vessels (SSVs) and many cytochrome oxidase (COX) positive raggedred fibers (RRFs) were observed, and A3243G mutations were found from the muscle samples. In two patients with MERRF, neither SSV nor COX positive RRFs were seen and A8344G mutations were found from both muscle and blood samples. In the two MERRF families, the identical mutation was observed among family members. The failure to detect the mutation in blood samples of the MELAS suggests a low mutant load in blood cells. The histochemical methods including COX stain are useful for the confirmation and differentiation of mitochondrial diseases. Also, molecular biological study using muscle sample seems essential for the confirmation of the mtDNA mutation.

Two Cases of Neuroleptic Malignant Syndrome

The neuroleptic malignant syndrome (NMS), a serious and potentially fatal complication, has been reported to occur in some patients with administration od neuroleptic medications. Its major manifestations are muscular rigidity, autonomic instability, altered consciousness, and hyperthermia, often accompanied by raised creatine kinase (CK) and leukocytosis. Manifestations of NMS are attributed to dopamine receptor blockade in the striatum, increasing thermogenesis, and in the hypothalamus, impaired heat dissipation. Owing to the potential lethality of NMS, the early diagnosis is important. The authors report two survived patients with the NMS who were treated by generalized supportive care and drug therapy.

Cryptococcal Meningoencephalitis Associated with Focal Cerobellar Iesion

Cryptococcal meningoencephalitis is one of the most cornInon fungal infections of the central nervous system, which mainly affects immunocompromised hosts, especially AIDS patients and patients with long-term steroid therapy. In advanced cases, it causes various complications such as encephailitis, hydrocephalus, and even death if not treated or inadequately treated. Authors have treated a case of cryptococcal meningoencephalitis with focal cerebellar lesion, whose primary infection sources were thought to be right frontal sinus and the ethmoidal sinus, with combination chemotherapy of amphotericine B and flucytosine.

A Case of Multiple Mononeuropathy Associated with Polyarteritis Nodosa

Polyarteritis nodosa(PAN) has been depicted as a necrotizing arteritis of small and medium-sized muscular arteries, affecting multiple organ systems throughout the body. The etiology of PAN remains unknown, but the histopathologic resemblance to chronic serim sickness has suggested an immune complex pathogenesis. The peripheral nervous system(PNS) is more frequently affected (in about 20-50% of patients) than the central nervous system(in about 10-20% of patients). Although multiple mononeuritis multiplex is generally considered to be the typical PNS manifestation of PAN, distal symmetrical polyneuropathy may occur more frequently than previous recognized. We report a case of polyarteritis nodosa with mononeuritis multiplex and distal symmetrical polyneuropathy, which was diagnosed by electrophysiological study and biopsies of muscle and sural nerve.