Familial Periodic Paralysis

Familial periodic paralysis presents a well-defined clinical picture. It was first described by Cavare (1853), whose findings have been supplemented by studies of the electrocardiogram (Janota and Weber, 1928), of the electroencephalogram (Watson, 1946), and of rare features such as non-familial incidence, protracted seizures, visceral involvement, and fatal complications (Smith, 1939). Precipitation of attacks has been ascribed to physical exertion and mental strain, indulgence in carbohydrates or alcohol, alimentary disturbance such as overeating, hunger, diarrhoea, or constipation, and exposure to cold or damp. Postulated relationships between this and other conditions -e.g., endocrinopathy (Shinosaki, 1926), migraine (MacLachlan, 1932), muscular dystrophy (Biemond and Daniels, 1934), spinal vascular spasm (Vernon, 1936), chemical defect of the neuraxis (Pudenz, McIntosh, and McEachern, 1938)-are inconstant and indefinite. The search for an adequate pathology was initiated by suspicion that muscular metabolism was deranged by some transitory autotoxaemia, which was suggested by arrest of gastric digestion and motility during the palsy (Mitchell, Flexner, and Edsall, 1902), and by transient urinary anomalies-e.g., acetonuria (Pastine, 1918), albuminuria (Shinosaki, 1926), and creatinuria (Ferrebee, Atchley, and Loeb, 1938). Recent studies of the blood chemistry of this syndrome have led to a fundamental advance in the state of knowledge as it existed between the review of the literature made by Singer and Goodbody (1901) and that by Schoenthal (1934). From a casual observation that the potassium content of the blood serum was lowered during the palsy (Biemond and Daniels, 1934) there developed a new line of inquiry (Walker, 1935). A low serum potassium was found in attacks induced by administration of glucose in large quantities and insulin, separately and together (Aitken, Allott, Castleden, and Walker, 1937), and by adrenaline injection (Allott and McArdle, 1938). Attention has been drawn to alterations in the phosphorus balance of the blood (Milhorat, 1937; Allott and McArdle, 1938), variations in electrolyte features of the blood (Ferrebee et al., 1938), and experimental evidence suggestive of a central controlling factor (Pudenz et al., 1938). The pathogenesis of this disease presumably depends upon an excessive call for potassium in the muscles, its consequent withdrawal from the blood and retention in the body, with parallel changes in phosphorus metabolism. Undue lability of the serum potassium and phosphorus in relation to sugar mobilization perhaps conditions some motor dysfunction, such as interference with transmission of nerve impulses or inhibition of the muscular contractile response. It has long been recognized that this palsy may be averted or arrested by the ingestion of various potassium saltse.g., the acetate (Singer and Goodbody, 1901), the carbonate, the chlorate (Mitchell et al., 1902), the bromide (Holtzapple, 1905), the chloride (Aitken et al., 1937), the citrate (Herrington, 1937), and the phosphate (Allott and McArdle, 1938). The success of prophylactic potassium medication at night (Allott and McArdle, 1938) is probably related to nocturnal lowering of serum potassium in this malady (Gammon, Austin, Blithe, and Reid, 1939). Symptoms have been controlled also by choline esters (Pudenz et al., 1938), pilocarpine (Guttmann, 1931), and pancreatic extract (Vernon, 1936), and averted by cod-liver oil (G.D.H., 1948). The following case, which illustrates typical familial and clinical features of this rare and remarkable malady, shows a prominent association between muscular exertion and paralytic seizures, a striking hemiplegic distribution of symptoms, and a prompt response to potassium therapy.