A 70 kg young athlete was planned for surgery. During anesthesia,vecuronium was not available so repeated doses of succinylcholine was given intermittently up to 640mg. During recovery ,patient was not able to spontaneously respire and more limbs. What is the cause

**Core Concept**
Succinylcholine is a depolarizing neuromuscular blocker that can cause hyperkalemia and potentially lead to malignant hyperthermia, especially when used in high doses or in susceptible individuals. The clinical scenario described suggests rhabdomyolysis, which can be caused by excessive succinylcholine administration.

**Why the Correct Answer is Right**
The repeated doses of succinylcholine in this patient likely caused rhabdomyolysis, a condition characterized by the breakdown of skeletal muscle tissue. This breakdown leads to the release of intracellular contents, including potassium, myoglobin, and other muscle enzymes, into the bloodstream. The high dose of 640mg succinylcholine is well above the recommended maximum dose of 400mg, increasing the risk of rhabdomyolysis. The inability to spontaneously respire and the presence of more limbs (likely muscle fasciculations) are consistent with this diagnosis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that succinylcholine should be used with caution in patients with a history of burns, trauma, or other conditions that may increase the risk of rhabdomyolysis. The recommended maximum dose of succinylcholine is 400mg, and doses above this should be avoided.

**Correct Answer: D. Rhabdomyolysis**

✓ Correct Answer: B. Phase 2 blockade