Hypokalemic periodic paralysis is an uncommon disease that has rarely been reported in blacks. Historical, clinical, and pathological findings in three black patients, in addition to those previously reported in the literature, suggest that the spectrum of the disease is identical in both blacks and whites. Considering the disease as either different or unknown in the black population is probably not justified

Bernstein, Jack M.

Kleerekoper, Michael

English

Henry Ford Health System Scholarly Commons

Henry Ford Hospital Medical Journal Volume 30 Number 2 Article 2 6-1982 Familial Hypokalemic Periodic Paralysis in Blacks Jack M. Bernstein Michael Kleerekoper Follow this and additional works at: https://scholarlycommons.henryford.com/hfhmedjournal  Part of the Life Sciences Commons, Medical Specialties Commons, and the Public Health Commons Recommended Citation Bernstein, Jack M. and Kleerekoper, Michael (1982) "Familial Hypokalemic Periodic Paralysis in Blacks," Henry Ford Hospital Medical Journal : Vol. 30 : No. 2 , 55-58. Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol30/iss2/2 This Article is brought to you for free and open access by Henry Ford Health System Scholarly Commons. It has been accepted for inclusion in Henry Ford Hospital Medical Journal by an authorized editor of Henry Ford Health System Scholarly Commons. Henry Ford Hosp Med J Vol 30, No 2,1982 Familial Hypokalemic Periodic Paralysis in Blackst Jack M. Bernstein, MD* and Michael Kleerekoper, MD Hypokalemic periodic paralysis is an uncommon disease that has rarely been reported in blacks. Historical, clini-cal, and pathological findings in three black patients, in addition to those previously reported in the literature. suggest that the spectrum of the disease is identical in both blacks and whites. Considering the disease as either different or unknown in the black population is probably not justified. Familial hypokalemic periodic paralysis is an uncom-mon syndrome characterized by flaccid paralysis of the skeletal muscles associated with hypokalemia. The para-lytic episodes are usually associated with profound hypokalemia and almost always aborted by the adminis-tration of potassium. Death due toeithercardiacarrythmias or paralysis of respiratory muscles is unusual. In North America, the disease has been reported almost exclu-sively in Caucasians. We have been able to find only four reports (1-4) com-prising four black families in whom this disease existed. In this paper, we report an additional two black families with familial hypokalemic periodic paralysis. Case Reports Case 1 A 22-year-old black woman was admitted to the hospital for evaluation of " l ow potassium." At the age of nine, she went to sleep one night on a hard f loor, and when she awoke the next morning she found that she could not move, although she could talk and swallow. She was given orange juice and within several hours regained her strength. Soon after, she was seen by a physician who told herthat she had " l ow potassium"; she received oral potassium supplementation which she has taken since. Attacks of paralysis occurred after she ate a meal, espe-cially those rich in carbohydrates, or drank soda pop. Occasionally, attacks were precipitated by cold or sleep. Exercise fo l lowed by rest induced an attack although cont inuing to exercise slowed the onset of weakness. Attacks occurred more frequently in the winter than in the summer, and thus, she needed less potassium triplex in the summer. She denies that she has chronic diarrhea or diabetes, uses diuretics, or eats large amounts of licorice. Her father (Case 2) is the only other affected member of this family. Physical examination revealed a young black woman in no apparent distress. General physical examination was normal except for a scar over the lower back secondary to an operation for scoliosis. Neurologic examination revealed minimal proximal weakness of the lower extrem-ities. Blood pressure was 106/70, pulse 96 and regular. Laboratory examination revealed sodium 132, potassium 4.1, chloride 104, and HCO324 with normal glucose and T4 on admission. On the third hospital day, 75.0 gm of glucose was infused over one-and-a-half hours. Two hours after first receiving the glucose, the patient evi-denced an objective decrease in strength with weakness of plantar f lexion and extension. In the next hour, the patient became almost completely paralyzed; only her facial and respiratory muscles were spared, and she was areflexic.The serum potassium at this time was 2.1 mEq/L. An electromyogram at this t ime showed a marked loss of motor unit activity, but the remaining motor units appeared normal in configuration and duration. Fre-quent P waves and fibrillations were seen. On full con-tract ion, there was rapid recruitment of motor units that appeared small and polyphasic. The patient was given Submit ted for pub l icat ion: September 8,1981 Accepted for pub l icat ion: October 19,1981 tThis paper received the Annual In-Training Manuscr ipt Award presented by the Henry Ford Hospital Medica l Journal. •Former ly , Department of Internal Med ic ine , Henry Ford Hospital ; presently. Department of Med ic ine , Marshall University, School of Med ic ine , Hun l i ng ton , West Virginia 25701 • •Depar tmen t of Internal Med i c i ne , Division of Bone and Minera l Metabo l i sm, Henry Ford Hospital Address reprint requests to Dr. Kleerekoper, Depar tment of Internal M e d i -c ine, Henry Ford Hospital , 2799 W Crand Blvd, Detro i t , M l 48202 55 Bernstein and Kleerekoper intravenousand oral potassium and bythe next morning she had recovered most of her strength. Repeat EMG showed marked improvement, but some myopathy remained. A muscle biopsy (Fig. 1) showed a vacuolar myopathy. The patient is presently doing well. She takes potassium supplements several times a week when she feels an attack beginning, and these successfully abort the attacks. Case 2 A 51-year-old black man, the father of the patient de-scribed above, went to sleep one night at the age of 13 and awoke paralyzed. He remained paralyzed although he was able to speak and swallow. He was carried f rom place to place, and after three days, he regained his strength. Major attacks came on approximately every three months and were precipitated by eating, espe-cially if fo l lowed by rest or too much exercise. "Keeping mov ing " sometimes ameliorated the attacks. By chance, he discovered that drinking orange juice or eating bananas shortened the period of paralysis. In 1955 at the age of 26, he was evaluated at another institution where hypokalemic periodic paralysis was diagnosed and potassium supplementation after each meal was prescribed. Through the late 1950s, the attacks came further and further apart, and he was able to decrease his potassium supplements unti l betook them only when his weakness started. In this way, complete paralysis was prevented. The periodic weakness was replaced by a generalized permanent weakness, and his lower extremities were more involved than his upper extremities. At present, he only rarely takes potassium. General physical examination was negative except for evidence of chronic lung disease, keratosis pilaris, and generalized muscle wasting. Reflexes were physiologic and symmetrical. Muscular strength was reduced; the most severe weakness involved the flexors of the hip and knee. The quadriceps femoris exhibited only minimal weakness. Both the deltoids and the triceps were weak-ened, but the biceps brachialis was normal. Accompany-ing the weakness was marked muscle wasting in these muscle groups. Laboratory examination revealed sodium 140, potassium 3.9, chloride 100, HCO3 37. Complete blood count, urinalysis, and VDRL were all normal or negative. Presently the patient is doing well and takes no medica-tions. His weakness does not significantly impair his activity, except for some difficulty in cl imbing stairs. Fig.1 Muscle biopsy. Vacuoles are present in several of the muscle fibers (hematoxyl in and eosin). Or ig inal magnif icat ion 25 X, enlarged to approximately X 750. Case 3 A 29-year-old black man was admitted to the hospital with quadriparesis. He had his first attack of weakness at the age df 13, when he awoke one morning paralyzed. He was admitted to another hospital, but the cause of the weakness was not found, and he was discharged after several days, after he recovered spontaneously. During the next year, when he had several further epi-sodes of paralysis, a diagnosis of hypokalemic paralysis was established. Over the next several years, the patient was hospitalized for paralysis many times. Attacks were precipitated by emotional upset, sleep, alcohol intake, heavy meals, or excessive exercise. In 1971, his therapy was changed to spironolactone (50 mg. p.o. t. i.d.), and he was placed on a low carbohydrate, low sodium diet. In spite of this, he had a severe attack of paralysis with respiratory decompensation that required intubation. His potassium at that t ime wasl .6mEq/L. Since then, the patient has done well with only occasional bouts of weakness. A brother died at the age of 21 dur ing an attack of paralysis, although no other family members, including parents and three siblings, are affected. Physical examination revealed a young black man with quadriparesis who was able to move his head and neck. He was areflexic. The remainder of the examination was normal. Blood pressure was 130/80, and pulse 80 and regular. Laboratory examination revealed sodium 140, potassium 1.7, chloride 112, HCO3 25. T4 was normal. Intravenous supplementation with potassium resulted in almost complete restoration of strength wi th in 24 hours. The 56 Familial Hypokalemic Paralysis in Blacks TABLE 1 Characteristics of Periodic Paralysis in Blacks Reference Age of Other Family Family Sex Onset Precipitating Factors Members Affected 1 1 Male 34 Meals, exercise, sleep Son 2 2 Male 23 Exercise, sleep Total of 27 members in Male 24 Exercise, high carbohydrate meal, sleep 4 generations, 15 men and 12 women : 3/27 died dur ing an attack. 3 3 Male 27 High carbohydrate meals, exercise, sleep Present report (Case 1) 4 Female 9 Cold, sleep, exercise, heavy meals Father Present report (Case 2) Male 13 hieavy meals, sleep, exercise Daughter Present report (Case 3) 5 Male 13 Emotional upset, sleep, a lcohol , heavy meals, exercise Brother (died dur ing attack) patient was discharged, and potassium supplementation was prescribed. He has done well since. Discussion Hypokalemic periodic paralysis classically has its onset dur ing the first to third decade of life. Wi th in each fam-ily, the age of onset is relatively constant though it may vary f rom family to family. It is thought to be inherited as an autosomal dominant with incomplete penetrance and affects men more than women (5). Clinically, several factors may predispose to an attack: exposure to cold temperatures, vigorous exercise fo l -lowed by rest, eating a meal rich in carbohydrates, or emotional upset (5,6). Eating refined carbohydrates or a large carbohydrate meal is the most common, precipitat-ing cause of paralysis. Most attacks occur as paralysis when the patient awakens. Attacks may last several hours to several days. They occur less and less frequently with the passage of t ime, sometimes completely abating in later life. Permanent myopathic weakness may occur as the sequela of years of recurrent attacks (6). Histologically, affected muscles show a vacuolar myopathy that is characteristic of hypokalemic paralysis but is also seen in other chronic hypokalemic states, systemic lupus erythematosus, chloroquine myopathy,steroid myopathy, and chronic polymositis (7). The pathology of the attacks is not completely under-stood. Between attacks of paralysis, the potassium con-tent of muscle increases dramatically, suggesting an intracellular shift o f t he potassium (8). In vitro studies by H of man and Smith (8) have shown that all diseased mus-cle specimens are significantly depolarized in vitro, irrespective of the patient's clinical condit ion. Insulin, at normal serum potassium concentrations, further depo-larizes the fibers. These findings may account for the patient's sensitivity to carbohydrate ingestion and to insulin. The disease has been treated with potassium supple-mentation or spironolactone. Recently, acetazolamide has been found to be effective in the prophylaxis of hypokalemic, as well as hyperkalemic, paralysis (9). On the basis of the five black families on whom we have clinical data, it would seem that the disease behaves identically to that in whites (6) (Table I). In blacks, the disease begins in the second or th i rd decade of life, but occasionally occurs late in the first or early in the fourth decades. Of 34 documented or clinically suspect cases (not including six cases [4] on whom there is no pub-lished clinical data), 12 women and 22 men were affected, indicating male predominance in spite of probably dominant inheritance (2). Factors which precipitated attacks (Table I) were identi-cal to those noted in the literature (5,6). We were partic-ularly impressed with the onset of weakness in two of 57 Bernstein and Kleerekoper our patients (Cases 1 and 3) after they drank sweetened soda pop and ate high carbohydrate meals. Four of the 34 patients died dur ing attacks, a prevalence similar to that which had previously been reported (5). Progression to permanent myopathic weakness as the patient grows older and attacks occur less often also seems to be the pattern in blacks. Our second patient, who is 51 years old at the present t ime, has obvious diffuse muscle wasting and generalized weakness although he no longer has acute exacerbations. His daughter (Case 1), who still suffers f rom hypokalemic paralysis, also has some early, permanent myopathic changes. Histologically, both our first patient and that of Martinez-Cat inchi, et al (3) had vacuolar myopathies with minimal atrophic changes. These findings are identical to those which have been previously reported (5). Conclusion We have seen three cases of hypokalemic periodic paralysis in two black families. The total number of blacks reported in the literature now totals 40 in six separate, apparently unrelated families. Clinical features including age of onset, inheritance, precipitating fac-tors, mortality, course and prognosis appear to be iden-tical to those seen in the Caucasian populat ion. To con-sider the disease in blacks as "almost unheard o f " (5) or dif ferent f rom that seen in whites is probably not justif ied. References 1. Forman BH. Hypokalemic periodic paralysis (Letter). JAMA1971; 216:146. 2. Corbett VA, Nuttal l FQ. Familial hypokalemic periodic paralysis in blacks. Ann Intern M e d 1975:83:63-5. 3. Mart inez-Cat inchi FL, Johnson CD, Cox RA. Hypokalemic per i -odic paralysis in a PuertoRican black (Letter). JAMA1977:237:447. 4. Glynn MF, Talso PS, Oester KT, Fudema J: Studies in familial periodic paralysis, Clin Res 1962:10:226. 5. Meyers FR. A summary review of the diagnosis and pathology of the primary famil ial per iodic paralyses. Ann Clin Lab Sci 1975:5: 216-21. 6. Pearson C M , Kalyanaraman K. The periodic paralyses. In : Stan-bury JB, Wyngaarden DS, eds. The metabol ic basis of inheri ted disease. New York: McGraw-Hi l l , 1972:1181-1203. 7. Kalyanaraman M D , Khurana R. Hypokalemic vacuolar myopathy of chronic alcohol ism: A histological and histochemical study. Dis Nerv Syst 1977:38:287-8. 8. Hofman W W , Smith RA. Hypokalemic per iodic paralysis studied in vitro. Brain 1970;93:445-74. 9. Resnich JS, Engel WK, Griggs RC, Stam AC. Acetazolamide pro-phylaxis in hypokalemic periodic paralysis. N Eng J M e d 1968:278: 582-6. 58 

Familial Hypokalemic Periodic Paralysis in Blacks

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Familial Hypokalemic Periodic Paralysis in Blacks

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