Question

Etiopathogenesis and types of Periodic Paralysis.

Hint:

Periodic paralysis is often triggered by changes in potassium levels or thyroid dysfunction. Genetic testing can help confirm the diagnosis.

Answer 1

Periodic paralysis is a group of disorders characterized by recurrent episodes of muscle weakness or paralysis, often triggered by specific factors such as potassium fluctuations, stress, or exercise. The key points about the etiopathogenesis and types of periodic paralysis are:
1. Etiopathogenesis:
- Genetic mutations: Periodic paralysis is primarily caused by autosomal dominant genetic mutations that affect the ion channels, leading to improper ion transport across muscle cell membranes. The most common mutations are found in the SCN4A gene, which encodes the sodium channel, and the CACNA1S gene, which encodes the calcium channel.
- Impaired ion exchange: Disruption in the movement of sodium, potassium, or calcium ions leads to improper muscle depolarization, resulting in episodes of weakness or paralysis.
- Electrolyte disturbances: Changes in the levels of potassium, sodium, or calcium in the blood are major triggers for attacks.
2. Types of Periodic Paralysis:
- Hypokalemic Periodic Paralysis: Characterized by episodes of muscle weakness associated with low levels of potassium in the blood. Attacks can be triggered by stress, exercise, or high carbohydrate meals.
- Hyperkalemic Periodic Paralysis: Characterized by episodes of muscle weakness or paralysis due to high potassium levels in the blood. These attacks can occur spontaneously or be triggered by factors like rest after exercise.
- Thyrotoxic Periodic Paralysis: A form of periodic paralysis that occurs in patients with hyperthyroidism, often presenting as sudden-onset paralysis associated with low potassium levels.