Gamstorp disease is one of the forms of transient muscle weakness associated with a sharp increase in the potassium content in the blood. Gamstorp disease is manifested by attacks of weakness occurring with varying frequency in the limbs and muscles of the face, which are accompanied by paresthesia, vegetative disorders, decreased reflexes and muscle tone without sensitivity disorders. Gamstorp disease is diagnosed on the basis of its typical clinical picture, data on the potassium content in the blood during the attack and inter-attack periods. Treatment includes a hypokalemic diet and taking diuretics that promote intensive excretion of potassium from the body.
G72.3 Periodic paralysis
Gamstorp disease was described in detail in the middle of the XX century by J. Gamstorp. It is one of the variants of paroxysmal myoplegia — paroxysmal severe weakness in the extremities, often leading to complete immobilization of the patient (paralysis). Unlike other myoplegias, Gamstorp disease is caused by a significant increase in the level of potassium in the blood. Gamstorp disease is much less common than the hypokalemic form of paroxysmal myoplegia (Westphal-Shakhnovich disease).
Gamstorp disease is a hereditary disease. In modern neurology, it is also called familial episodic adynamia. The inheritance of Gamstorp disease occurs according to the autosomal dominant principle and is characterized by complete penetrance of the gene. The disease is often traced in several generations of the same family. Women and men get Gamstorp disease with approximately the same frequency.
Characteristic is the occurrence of the first attack in the first 10 years of life, most often before the age of 5. As a rule, an attack begins with a feeling of heaviness arising in the extremities, and paresthesia (numbness, tingling) of the face and limbs. Then total muscle weakness appears, it increases rapidly and within 30 minutes reaches the degree of pronounced paresis or complete paralysis. During an attack of Gamstorp disease, there is a decrease in muscle tone (muscle hypotension), loss of tendon reflexes, vegetative disorders: pallor, “marbling” or redness of the skin, dry skin, tachycardia, lability of blood pressure, hyperhidrosis and severe thirst. Often, an attack of Gamstorp’s disease is accompanied by weakness of the facial muscles, which is manifested by a violation of articulation (dysarthria) and facial expressions (“masked face”).
Unlike Westphal-Shakhnovich’s disease, pathology is characterized by the development of seizures in the daytime. Factors provoking an attack are usually physical overload, starvation, hypothermia. In most cases, Gamstorp disease is accompanied by seizures of short duration (1-3 hours), but in some cases the attack is observed for several days.
Disease can occur with different frequency of attacks — from several times a year or a month to daily paroxysms. The intensity of seizures and the degree of severity of motor disorders during an attack in Gamstorp disease also varies and may be different from attack to attack. At the same time, complete paralysis develops quite rarely. Gamstorp disease is characterized by the absence of any neurological abnormalities in the intercrime period.
Gamstorp disease can be assumed by the presence of characteristic seizures and the familial nature of the disease. To distinguish Gamstorp’s disease from other types of paroxysmal myoplegia (hypo- and normokalemic) allows a biochemical study of blood taken for analysis during the attack. An increase in the level of potassium in the blood serum to 6-7 mmol / l during the attack and its normalization outside the attack allow the neurologist to confirm the diagnosis.
Gamstorp disease must be differentiated primarily from Landry’s ascending paralysis. This is possible with a thorough study of the clinical picture of the attack (absence of sensitivity disorders and an increase in body temperature) and analysis of the results of the study of the electrolyte composition of the blood. It is also necessary to differentiate the attacks of Gamstorp’s disease from epileptic seizures. Electroencephalography is of auxiliary importance for the exclusion of epilepsy. In doubtful cases of Gamstorp’s disease, CT or MRI of the spine can be performed, which does not reveal any abnormalities and thereby allows to exclude organic pathology (hematomyelia, central nervous system tumor, polio, cerebrospinal circulation disorder).
It should also be remembered that myoplegic syndrome can occur in some endocrine diseases (hyperthyroidism, hyperaldosteronism, pangypopituitarism, adrenal tumors, hypercorticism), gastrointestinal pathology (malabsorption syndrome, enterocolitis, liver cirrhosis), kidney disorders (nephrotic syndrome, renal failure). However, these diseases are usually accompanied by a decrease in potassium levels, while Gamstorp’s disease is characterized by its increase. Hyperkalemia may be accompanied by adrenal insufficiency, but the absence of other typical symptoms for it and a blood test for the content of adrenal hormones makes it possible to exclude this diagnosis.
The therapy of Gamstorp disease consists in limiting the intake of potassium from food and in drug stimulation of its withdrawal from the body. Patients with Gamstorp disease are recommended a diet rich in carbohydrates, with an increased content of table salt and a restriction of potassium-containing products (milk, kefir, cheese, dried apricots, prunes, dried fruits, etc.). It is necessary to adhere to a fractional diet with small intervals between meals.
For the purpose of enhanced excretion of potassium in the urine, diuretics are prescribed: hydrochlorothiazide, furosemide. Relief of an attack in Gamstorp disease is carried out by intravenous administration of 40 ml of 40% glucose with insulin or 20 ml of 10% calcium chloride. Some authors point to the positive effect of inhaled administration of salbutamol.