Hypokalemic vs. Hyperkalemic periodic paralysis – High Yield NEET PG & INI – CET guide
Why This Topic is Important for NEET PG & INI-CET
Periodic paralysis disorders are commonly tested in NEET PG and INI-CET. A solid grasp of hypokalemic and hyperkalemic periodic paralysis will help in answering questions correctly. These conditions involve ion channel activity affecting muscle function, leading to temporary paralysis. Let’s break it down in a high-yield, exam -focused manner.
What is periodic paralysis?
Periodic paralysis refers to rare neuromuscular disorders characterized by episodes of muscle weakness or paralysis triggered by fluctuation in serum potassium levels. The two main types are mentioned in the tabular format highlighting key differences.
Mnemonic to remember
“HYPO has HIGH triggers, HYPER has Low Triggers”
- HYPO Kalemic Paralysis = HIGH Sugar & Carb intake causes an attack .
- HYPER Kalemic paralysis = LOW Food intake (Fasting) triggers the episode.
| Key differences – High – Yield Table | ||
| Feature | Hypokalemic Periodic Paralysis | Hyperkalemic Periodic paralysis |
| Cause | Mutation in CACNA1S/SCN4A gene Primary answer as calcium channel defect | Mutation in SCN4A gene Primary answer as sodium channel defect |
| Serum potassium during attack | Low (<3.5 mEq/L) | High (>5.0 mEq/L) |
| Triggers | High -carb meals, exercise, stress | Fasting, rest after exercise |
| Onset | Teenage years (10-20 years) | Early childhood |
| Duration of Attack | Hours to days | Minutes to hours |
| Reflexes | Reduced | Normal |
| Treatment | Potassium supplementation, avoiding triggers | Glucose, diuretics (thiazides) |
Clinical cases to remember
| Hypokalemic Periodic Paralysis | Hyperkalemic Periodic Paralysis |
| A 15-year-old male wakes up with sudden muscle weakness after eating a large pizza and soda the previous night Blood tests show low serum potassium ( 2.5 mEq/L) | A 6-year-old child experiences muscle weakness after skipping breakfast. Symptoms resolve spontaneously after a few hours. Blood tests show elevated potassium ( 5.6 mEq/L). |
Diagnosis & Investigations
- Serum potassium levels during an attack
- Electromyography (EMG): Shows myotonic discharges in Hyper PP
- Genetic testing: Confirms mutations in SCN4A (Hyper PP) and CACNA1S/SCN4A (Hypo PP)
- Exercise Test: Potassium levels drop in Hypo PP and rise in Hyper PP
Treatment Approach – High Yield Table
| Condition | Acute attack Management | Long-Term prevention |
| Hypokalemic PP | Oral /IV potassium | Avoid high-carb meals, Acetazolamide |
| Hyperkalemic PP | Glucose + insulin, diuretics | Low potassium, diet, acetazolamide |
Exam Pearls – Must – Know for NEET PG & INI- CET
- Hypokalemic PP is often linked to thyrotoxic periodic paralysis – commonly seen in Asian populations.
- Hyperkalemic PP is associated with myotonia (delayed muscle relaxation after contraction).
- Acetazolamide is used in both conditions as it stabilizes ion channels but can worsen type 2 RTA.
📌Related High – Yield Topics to Read click on this link https://www.marwahmedicine.com/blogs/
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