Quiz Form

Question Date: 02/10/2023

Question: 32 year old lady presented with optic neuritis and paraparesis. MRI brain and orbit and spine showed demyelinating plaques. There was long segment myelitis and optic neuritis involving the optic chiasma. CSF Routine showed 5 cells and 80mgdl proteins. Serum NMO antibody was positive. She was started on Inj Methylprednisolone and azathioprine 50 mg 1-0-1. Her symptoms improved however three weeks later she developed fever and pancytopenia<br><br>Which of the following laboratory test results could explain her pancytopenia cause?

Options:

• TPMT genotyping
• Bone marrow examination
• Serum erythropoietin
• Parvovirus PCR

Correct Answer: TPMT genotyping

Explaination: Patients with low activity of thiopurine methyltransferase due to SNP of TPMT gene, have thiopurine toxicity which causes myelotoxicity

Reference: Chan, A., Pirmohamed, M. & Comabella, M. Pharmacogenomics in neurology Current state and future steps. Annals of Neurology 70, 684697 (2011).