[Hereditary episodic adynamia. Gamstorp's disease]

The authors report a family in which the mother and her one son had typical eipsodes of flaccid muscular paralysis with raised serum potassium level during the episode. In the period between these episodes only myotonia was observed. Histological examinations and EMG confirmed the diagnosis. Myotonia was present in two other siblings.

Hypothyroidism with subacute pseudomyotonia--an early form of Hoffmann's syndrome? Report of a case

A 25-year-old man was admitted to the hospital because of painful muscle cramps and action myospams of subacute onset and 6 weeks' duration. No myotonia could be demonstrated objectively and his deep tendon reflexes showed no prolongation of the relaxation phase. Serum creatinine was raised but creatinine clearance was normal. Serum levels of aldose, CPK, ASAT and ALAT were increased but ordinary light microscopy revealed no histological signs of muscle disease in a quadriceps biopsy. ECG showed a prolonged PQ interval and flat T waves in the left precordial leads. Laboratory tests of thyroid function revealed intensive hypothyroidism, and high titers of circulating thyroid antibodies were demonstrated. During 2 1/2 months of thyroid therapy, the muscle symptoms gradually disappeared completely and the patient could return to work. By that time the serum enzymes and the ECG had normalized. Despite the lack of objective signs of myotonia, we consider that the very dominant subjective muscle symptoms, severe enough to prevent the patient from performing his ordinary manual work and completely reversible on thyroid therapy, justify the designation of hypothyroid myopathy. The question is raised whether the case represents an early form of Hoffmann's syndrome.

Neuropathy in myotubular or centronuclear myopathy

A detailed electrophysiological study has been made of the extensor digitorum brevis, thenar, hypothenar and soleus muscles in one patient with myotubular or centronuclear myopathy. The main finding was a noticeable reduction in the population of active motor units in all the investigated muscles. The remainer units showed normal sizes. The experimental observations have been interpreted in terms of a neuropathic process.

Genetic approaches to the nosology of muscular disease: myotonias and similar diseases

Besides myotonic dystrophy some generalized myotonias exist, until now mostly diagnosed as "Thomsen's disease." It is questionable whether the dominant "myotonia congenita" is homogeneous. Surely there is at least one recessive type of generalized myotonia, which is also clinically different from Thomsen's disease. Paramyotonia congenita Eulenburg is a genetically independent type separated from paralysis periodica paramyotonia. Further diseases with myotonia and some other diseases of differential disgnostic importance with regard to myotonias are mentioned