What Is Hyperkalemic Periodic Paralysis?

Periodic paralysis, also known as periodic paralysis, refers to a group of diseases that are characterized by recurrent paroxysmal flaccid paralysis of the skeletal muscles. Most of them are accompanied by abnormal changes in serum potassium concentration levels. Divided into three types of low potassium, normal blood potassium and high potassium. Low-potassium periodic paralysis is the majority in clinical practice, and normal blood potassium and high-potassium periodic paralysis are rare.

Basic Information

Visiting department

Neurology

Multiple groups

male

Common causes

Due to hyperthyroidism, primary aldosteronism, 17-hydroxylase deficiency, barium poisoning, etc.

Common symptoms

Flaccid paralysis of limbs and trunk, early and heavy muscle involvement

Causes of periodic paralysis

According to the cause, it can be divided into two types: primary and secondary. Primary refers to those whose pathogenesis is unknown and hereditary; secondary is caused by changes in blood potassium caused by other diseases, and is found in hyperthyroidism, primary aldosteronism, 17- Hydroxylase deficiency, barium poisoning, ingestion of glycyrrhizic acid preparations, and abuse of thyroid hormones.

Clinical manifestations of periodic paralysis

1. Hypokalemia periodic paralysis

The disease can occur at any age, and it is mostly in early childhood to 40 years old, as early as 4 years old and late to 60 years old. There are more men than women, and the number of cases decreases with age. Full meals (especially excessive carbohydrate intake), alcoholism, strenuous exercise, overwork, cold or emotional stress, or napping can all be induced.

Typical seizures occur at night or early in the morning, peaking within a few hours and manifesting as flaccid paralysis of the limbs and trunk, with early and heavy muscle involvement. The degree can be light or heavy. Muscle weakness usually begins with both lower limbs, extends to both upper limbs, is symmetrical on both sides, and is heavier at the proximal end; muscle tension decreases and tendon reflexes weaken or disappear. The patient was sober, with normal articulation, rarely affected head and facial muscles, and normal urine and stool functions. Severe cases can involve the diaphragm, respiratory muscles, myocardium, and even death. Seizures usually last 6 to 24 hours, or 1 to 2 days, and individual cases can last for several days. Early affected muscles tend to recover first. All episodes are normal; the frequency of the episodes varies, which can be once every few weeks or months. Individual cases have frequent episodes, even every day, and once in several years or only once in a lifetime. With the increase of age, the frequency of the disease gradually decreases until it stops. If it is complicated by adrenal tumors and hyperthyroidism, the attacks are often more frequent. Muscle pain and stiffness may persist for several days after the attack, and may be accompanied by polyuria and sweating. Frequent authors may have persistent lower limb weakness and localized muscular atrophy.

Atypical cases can manifest as weakness in one limb or some muscle groups, paralysis of the arms can not raise the arms, transient weakness during habitual movements, and daily transient episodes are related to exposure to cold. Some patients have deformed feet at an early age and develop chronic chronic proximal myopathy at middle age, accompanied by myofiber vacuoles, degeneration, and myopathic action potentials.

2. Hyperkalemia-type periodic paralysis

Rarely, mainly found in Nordic countries, mostly autosomal dominant inheritance, onset from infancy to childhood (before 10 years old), often caused by hunger, cold, infection, pregnancy, strenuous exercise or taking potassium, during the day Onset. Potassium ions enter the plasma from the muscles during the onset, and the potassium level rises to 5-6 mmol / L. Symptoms of weakness are also heavy near the lower extremities. Some patients may have signs of tonicity during the onset, such as involving the face and hands, facial "rigidity", half-closed eyes, stiff hand muscles, flexion of fingers and abduction. The duration of the attack is short, less than 1 hour. Mild weakness lasts for 1 to 2 days after each attack. The frequency of attacks is multiple times a day or once a year. Eating, general activities, intravenous calcium, insulin or epinephrine can stop the attack. Some patients with recurrent attacks may have permanent weakness and apraxia of the proximal muscles of their limbs. Diuretics such as acetazolamide and hydrochlorothiazide, which can increase potassium excretion, can be used to prevent seizures.

3. Periodic paralysis of normal blood potassium

Also known as sodium-reactive normal blood potassium type periodic palsy, it is rare, it is autosomal dominant inheritance, and has the same genetic mutation as high potassium type periodic palsy. Onset before the age of 10 years, the triggers are similar to low potassium periodic paralysis. Extreme seizures, thirst and other symptoms are often present before the attack. The main symptoms are paroxysmal weakness, severe speech insufficiency and difficulty breathing. Its symptoms are similar to periodic hypoparalysis of hypokalemia, but the duration is more than 10 days; similar to periodic paralysis of hyperkalemia, it can be induced by potassium salt. However, the difference between the two is that the blood potassium concentration during the attack is normal, and the application of a large amount of saline infusion during the attack can restore paralysis. If the amount of salt is reduced, the clinical attack can be induced.

Periodic paralysis

Serum potassium test

Periodic paralysis of hypokalemia type, serum potassium decreases during onset, often below 3.5mmol / L; Periodic paralysis of hyperkalemia type, serum potassium increases during onset, which can reach 5-6 mmol / L; period of normal blood potassium type Blood potassium was normal during the onset of paralysis.

2. ECG examination

When hypokalemia occurs, the electrocardiogram often has hypokalemia changes such as PR interval, QRS plexus and QT interval prolongation, ST segment decline, T wave low level, U wave is obvious and often merges with T wave. Hypokalemia often decreases earlier than serum potassium. At the onset of hyperkalemia periodic paralysis, the changes of the electrocardiogram were initially increased T wave, QT interval prolonged, and then gradually reduced R wave, S wave deepened, ST segment decreased, PR interval and QRS time prolonged.

Diagnosis of periodic paralysis

According to the characteristics of patients with intermittent myasthenia gravis, combined with tendon reflexes, serum potassium concentration, and changes in electrocardiogram during the onset, it is generally not difficult to make a diagnosis. However, it should be noted that to determine whether low-potassium periodic paralysis is primary or secondary, the treatment of the cause is the key.

Periodic paralysis treatment

1. Low potassium type periodic paralysis

Adults take potassium chloride orally or nasally at a time. For those with respiratory muscle paralysis, artificial respiration, sputum and oxygen should be given in time. Cardiac arrhythmia can be applied intravenously with 10% potassium chloride, insulin and 5% glucose solution. But digitalis is prohibited. Intermittent treatment of seizures: those with more frequent seizures can take potassium chloride orally every night before bedtime. If there is hyperthyroidism or adrenal cortical masses, corresponding drugs or surgical treatment should be performed. Still need to be alert to individual patients who still have arrhythmia, difficult to treat, and can die due to ventricular tachycardia. In general, you should avoid inducements such as overwork and oversaturation.

2. High potassium type periodic paralysis

Mild attacks usually do not require treatment. For more severe attacks, you can choose: 10% calcium gluconate or calcium chloride 10 ~ 20ml intravenous injection. Insulin 10 20U was added with 500ml of 10% glucose solution. 4% sodium bicarbonate solution. Hydrochlorothiazide or furosemide potassium excretion treatment.

The intake of potassium should be controlled during the intermittent period, mainly the sources of potassium that are easily overlooked, such as potassium penicillin and stock blood for more than a week. Usually eat a high salt, high carbohydrate diet.

3. Periodic paralysis of normal blood potassium

Can use saline or 5% dextrose saline intravenously during the onset, and try to take table salt. Take potassium-removing sodium and other drugs such as acetazolamide or glucocorticoid. However, excessive potassium excretion can be transformed from this type to low potassium periodic paralysis, which should be paid attention to. Usually should take a high-salt and high-sugar diet. Those with frequent attacks can take potassium-removing and sodium-preserving drugs to prevent or reduce their onset.

Periodic paralysis prevention

1. Low potassium type periodic paralysis

A variety of triggering factors should be avoided, such as cold, full meals and a lot of carbohydrates. More frequent attacks, taking acetazolamide in the intermittent period (2 to 4 times a day), or acetone (4 times a day) can prevent the disease. Low sodium and high potassium diets or taking potassium chloride daily can also help reduce seizures. For patients with secondary periodic paralysis, removal of the primary disease is the best prevention.

2. High potassium type periodic paralysis

Those with frequent attacks should be given a high-carbohydrate diet during the intermittent period, taking acetazolamide (2 to 4 times a day), or hydrochlorothiazide (2 to 3 times a day), or dichlorobenzenedisulfonamide to prevent the attack.

3. Periodic paralysis of normal blood potassium

A variety of triggering factors should be avoided, such as cold, full meals and a lot of carbohydrates. Extremely halophilic patients should be avoided if they are induced by limiting salt or given potassium. Some patients are given acetazolamide intermittently (2 to 4 times a day) or low-dose glucocorticoids can prevent seizures.