Question

Plasmapheresis is used in all of the following except:

• A. Myasthenic crisis
• B. Cholinergic crisis
• C. Guillain-Barre syndrome
• D. Polymyositis

Hint:

Plasmapheresis clears antibodies; a cholinergic crisis is a drug overdose, so it does not apply.

Answer 1

The Correct Option is B

Step 1: This is a negative question. Plasmapheresis removes circulating antibodies and immune complexes from plasma, so it helps antibody mediated and autoimmune diseases. Find the condition where it does not apply.
Step 2: Myasthenic crisis (option A) is severe weakness from anti acetylcholine receptor antibodies, often with respiratory failure. Plasmapheresis rapidly removes these antibodies and is a standard rescue treatment, so it is used here.
Step 3: Guillain-Barre syndrome (option C) is an autoimmune demyelinating polyneuropathy. Plasmapheresis is a proven first line therapy that removes the offending antibodies and shortens recovery, so it is used here.
Step 4: Polymyositis (option D) is an autoimmune inflammatory myopathy. In refractory cases plasmapheresis may be used as part of immune directed therapy, so it can be applied here.
Step 5: Cholinergic crisis (option B) is caused by an excess of anticholinesterase drugs, leading to too much acetylcholine at the junction. This is a drug overdose problem, not an antibody problem. It is treated by stopping the drug, giving atropine, and supporting ventilation, not by plasmapheresis.
Step 6: Therefore plasmapheresis is not used in cholinergic crisis.
Answer: Option B.