Which among the following is contraindicated in myasthenia patient?
**Core Concept**
Myasthenia gravis is an autoimmune disease characterized by the production of antibodies against acetylcholine receptors (AChRs) at the neuromuscular junction, leading to muscle weakness and fatigue. The primary goal of treatment is to increase the concentration of acetylcholine available for neurotransmission, thereby improving muscle function.
**Why the Correct Answer is Right**
Succinylcholine (A) is a depolarizing muscle relaxant that acts by activating AChRs for an extended period, leading to prolonged muscle paralysis. In myasthenia gravis patients, succinylcholine can cause a severe exacerbation of muscle weakness due to its prolonged action on the already compromised AChRs. This is because the disease is characterized by the reduced number of functional AChRs, making it difficult for the muscle to recover from the depolarizing effect of succinylcholine.
**Why Each Wrong Option is Incorrect**
**Option B:** Atracurium, a non-depolarizing muscle relaxant, is not contraindicated in myasthenia gravis patients. Non-depolarizing muscle relaxants can be used cautiously in these patients, as they do not activate AChRs and can be reversed with anticholinesterases.
**Option C:** Aminoglycosides, a class of antibiotics, are not directly contraindicated in myasthenia gravis patients. However, they can exacerbate muscle weakness by interfering with acetylcholine release and increasing the concentration of neuromuscular blocking substances.
**Option D:** Cisatracurium, a non-depolarizing muscle relaxant, is not contraindicated in myasthenia gravis patients. Cisatracurium is a more selective relaxant with a lower risk of inducing histamine release compared to atracurium.
**Clinical Pearl / High-Yield Fact**
In myasthenia gravis patients, it is essential to use non-depolarizing muscle relaxants cautiously and to monitor for signs of neuromuscular blockade. Anticholinesterases, such as neostigmine, can be used to reverse non-depolarizing muscle relaxants in these patients.
**Correct Answer:** A. Succinylcholine is contraindicated in myasthenia gravis patients due to its depolarizing effect on already compromised acetylcholine receptors.