Introduction
Hyperkalemic periodic paralysis occurs as an autosomal dominant inheritance, indicating that one copy of a mutated gene is enough to cause the disorder. This disorder can be identified clinically as they present with weak limbs and seem to be clumsy or easily irritable. Proper diagnosis can be done by correlating the clinical features with laboratory testing or gene testing. Symptomatic treatment is given to treat the condition, and proper follow-up and surveillance are necessary for the betterment of the treatment.
What Is Hyperkalemic Periodic Paralysis?
Hyperkalemic periodic paralysis is a genetically acquired condition due to a mutation of the gene SCN4A. It mostly presents with muscle weakness as the mutated gene shows its impact directly on the muscles, affecting the overall activities of the individual. Though not a fatal condition in most cases, care should be taken at the earliest to diagnose and treat the condition.
What Are the Causes of Hyperkalemic Periodic Paralysis?
Genetic mutations in the gene SCN 4A lead to hyperkalemic periodic paralysis. A protein encoding for the apt functioning of muscles, which helps in movement, is made according to the instructions given by the gene SCN4A. For the body to move, there has to be continuous contraction and relaxation of the muscles in a coordinated manner. This occurs with the help of ions like sodium (positively charged atoms), which flow through channels. The channels are formed by the gene SCN4A, which controls the movement of ions. Alterations in the gene lead to alterations in its functioning, which do not stay open for a long or remain closed for a long period, allowing more sodium ions to pass into the muscle cells. This, in turn, increases the release of potassium from the muscles, reducing the skeletal muscle's ability to contract or relax, leading to muscle weakness and altering body movements.
What Are the Symptoms of Hyperkalemic Periodic Paralysis?
The frequency of the paralysis attacks increases with time under 50 years, after which there is a decline in the frequency.
The attacks can be triggered by agents such as a cold environment, stress, hunger, relaxation after exercise, potassium-rich foods, extra sleep, pregnancy, menstruation, and medication.
Following are the symptoms noticed:
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Muscle weakness.
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Stiffness in arms or hands.
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Clumsiness and irritability.
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Myotonia muscle stiffness in the face and eyelids.
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Paramyotonia (stiffness occurring due to exercise and coldness)
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Muscle atrophy (muscle wasting).
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Thyroid dysfunction (alteration of thyroid function leading to decreased or increased production of thyroid hormone).
What Is the Diagnosis for Hyperkalemic Periodic Paralysis?
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Clinical findings help in diagnosing the condition along with EMG (electromyography) and gene testing.
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History of nearly two attacks of weakness in muscles of the eyes or trunk, along with breathing difficulties from the past month.
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Laboratory testing for serum creatinine and serum potassium can be elevated.
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Electromyography can show certain features indicating altered muscles.
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Although laboratory findings help in establishing the diagnosis, confirmation of the diagnosis can be done by performing molecular genetic testing. This includes single-gene testing and comprehensive genomic testing.
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The mutation in the genes can be identified by these tests confirming the diagnosis.
What Is the Treatment for Hyperkalemic Periodic Paralysis?
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Symptomatic treatment is suggested for the disorder.
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Attacks of muscle weakness can be corrected by exercising and consumption of carbohydrates during the weakness. Intravenous administration of Glucocorticoids or administration of Salbutamol can help in preventing the attacks.
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Calcium gluconate administered intravenously can also help in terminating the attacks in certain cases.
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Decreased muscle tone can be treated by inhalation of oxygen incorporating a non-depolarizing muscle relaxant, which is followed by intubation.
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Respiratory or general muscle weakness can be prevented by glucose infusion, maintaining normal body temperature, and maintaining potassium levels at their lowest.
What Are the Primary Preventive Manifestations?
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Diet or Environment: Consumption of meals that are rich in carbohydrates and avoiding fruits and fruit juices that are potassium-rich foods, avoiding fasting and tiring work.
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Starting the Day Early: Attacks usually occur when people rest in bed for a long time, like on weekends or holidays. For this reason, individuals are advised to have a complete breakfast after rising early.
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Lifestyle: Agents that trigger the weakness should be avoided by keeping low stress and avoiding intense exercise.
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Diuretics: Increased potassium leads to hyperkalemic attacks of muscle weakness, and to prevent them, Diuretics can be used. Thiazide diuretics are preferable because they show minimal side effects. It should be noted to keep the dosage at the lowest levels possible.
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Surveillance: It is recommended to keep individuals with hyperkalemic periodic paralysis under surveillance. Monitoring every six months concerning diuretic-induced hypokalemia is necessary to maintain the levels of serum potassium. Muscle weakness can be evaluated by neurologic examination or by conducting an MRI (magnetic resonance imaging) scan of the leg muscles every year. A thyroid functioning test is also advised every year to monitor thyroid function.
What Are the Agents to Avoid When Diagnosed With Hyperkalemic Periodic Paralysis?
Depolarizing agents or opioids, used as a part of general anesthesia, should be avoided as they can increase or elevate the muscle reaction, leading to pain and stiffness of the muscles that can also impair mechanical ventilation.
Arterial hypertension is treated using ACE (angiotensin converting enzyme) inhibitors, which should be avoided as they can cause hyperkalemia as a complication when combined with Diuretics, leading to kidney function impairment.
What Is the Management for Hyperkalemic Periodic Paralysis in Pregnant Women?
The frequency of hyperkalemic periodic paralysis during pregnancy is up to 90 %, and nearly 80 % of them recover. Treatment with diuretics on a chronic basis can be continued during pregnancy. A higher risk to the infant has not been reported when the mother is exposed to the treatment.
Conclusion:
Hyperkalemic periodic paralysis is a genetic disorder that occurs in the parents, even if one of them shows a mutation. Generally, it can be diagnosed with the help of clinical presentation, family history, and certain laboratory findings of serum potassium and sodium levels. Once the diagnosis is done, symptomatic treatment can be started. Genetic testing can also be carried out to estimate the diagnosis in individuals not showing clinical findings. Genetic counseling is also necessary to know and evaluate the prevalence of the disorder in the family.
