Hypokalemic periodic paralysis is a rare autosomal dominant genetic disorder characterized by recurrent attacks of skeletal muscle weakness with associated hypokalemia which is precipitated by stress, cold, carbohydrate load, infection, glucose infusion, hypothermia, metabolic alkalosis, anesthesia, and steroids.
It is an autosomal dominant,inherited disorder, caused by mutations in calcium, sodium, or potassium channels of skeletal muscles.
The pathophysiology of FHPP involves mutations in genes encoding ion channels in skeletal muscle, primarily the voltage-gated calcium channel alpha-1 subunit (CACNA1S) and the sodium channel alpha subunit (SCN4A).
It is most often diagnosed in patients younger than 20 years of age who are Asian descent and have a family history of the disease.
HKPP, a rare genetic disorder with autosomal dominant inheritance and characterized by recurrent attacks of skeletal muscle weakness with associated hypokalemia which is precipitated by stress, cold, carbohydrate load, infection, glucose infusion, hypothermia, metabolic alkalosis, anesthesia, and steroids.
Hypokalemic familial periodic paralysis is a rare channelopathy with muscle weakness and a matching fall in the potassium levels in the blood.
it is a autosomal dominant genetic disorder in the gene encoding for the dihydropyridine sensitive calcium channel.
The weakness may be limited to muscle groups or may present as more severe muscle paralysis.
The decrease in potassium is associated with abnormal uptake of potassium by the muscle cells.
It usually presents either as a paralytic form or as a paramyotonic form.
Factors that trigger weakness or paralysis are anesthesia, surgery, pregnancy, insulin, alcohol, strenuous exercise, and steroids.
Care includes control of plasma potassium, avoidance of large glucose and salt loads, maintenance of body temperature, acid–base balance, and careful use of neuromuscular blocking agents.
Allaying anxiety, avoiding stress and adequate analgesia is vital in preventing an attack.
Fluctuations in electrolytes, infection, and pain can lead to periodic paralysis in the post-operative period.
Hypokalemia manifests earlier than paralysis.
Preventing hypokalemia can prevent paralysis.
Dextrose intravenous solutions administered during surgery should be avoided and normal saline (0.9%) should be preferred.
Patients often report additional symptoms either before, during, or after attacks: including paresthesias, sweating, myalgia, extreme fatigue, thirst, shortness of breath, palpitations, clumsiness, irritability, and mental dullness.
Provocative testing can be dangerous.
Potassium challenge tests risk hyperkalemic arrhythmia.
Insulin challenge tests can be equally dangerous due to risk of hypoglycemia.
Simple exercise challenge, which is relatively safe, is partly helpful when the serum potassium is high or low.
Specifically, ECG, TSH, free T3 and free T4 are the minimum indicated laboratory investigations, with renal and adrenal function also recommended.
These disorders are autosomal dominant with male preponderance.
The condition typically manifests in childhood or adolescence and is often triggered by factors such as rest after exercise, carbohydrate-rich meals, or certain medications.
These mutations lead to dysfunctional ion channel activity, resulting in abnormal muscle membrane excitability and subsequent muscle weakness during hypokalemic episodes.
Clinically, patients experience transient episodes of flaccid muscle weakness, which can last from hours to days.
Episodes can vary in frequency from daily to infrequent occurrences.
Between attacks, muscle strength is typically normal, although some individuals may develop persistent muscle weakness over time.
Management of FHPP focuses on preventing and treating acute attacks.
Acute episodes are managed with potassium supplementation to restore normal serum potassium levels.
Lifestyle modifications to avoid known triggers and, in some cases, the use of medications such as acetazolamide, which can help reduce the frequency and severity of attacks.