# Neuromyelitis Optica spectrum disorder complicated with pure red cell aplasia: a case report

## TL;DR

A patient with neuromyelitis optica spectrum disorder developed pure red cell aplasia, a blood disorder not previously reported in this condition.

## Contribution

This is the first reported case of pure red cell aplasia complicating neuromyelitis optica spectrum disorder.

## Key findings

- A 54-year-old NMOSD patient developed PRCA, confirmed by bone marrow biopsy.
- Treatment with recombinant human erythropoietin improved blood cell counts and symptoms.
- The case highlights the need for immune and bone marrow evaluation in NMOSD patients with blood abnormalities.

## Abstract

Pure red cell aplasia (PRCA) in neuromyelitis optica spectrum disorder (NMOSD) has not been reported before. This study presents a patient with NMOSD who developed PRCA.

A 54-year-old female was admitted in January 2023 for dysuria and progressive numbness and weakness of lower limbs. She had difficulty standing and walking in a straight line. Both lower limbs were positive for the Babinski and Chaddock signs. MRI showed abnormal signals in the spinal cord. Aquaporin-4-IgG (AQP-4-IgG) was positive (1:320), and NMOSD was confirmed. Intravenous immunoglobulin and methylprednisolone were given, and the symptoms improved. She received maintenance treatment with methylprednisolone tablets, and the dosage was gradually reduced. She was readmitted for fatigue, palpitations, and shortness of breath in May 2023. Bone marrow aspiration and biopsy showed elevated erythroid precursors and erythroid hypoplasia, with normal megakaryocytes and myeloid precursors. Chest CT showed no mediastinal lymph node enlargement or thymoma. PRCA secondary to NMOSD was diagnosed. Recombinant human erythropoietin was given. Her condition improved after 1.5 months, as indicated by blood cell count and imaging.

This case suggests that PRCA can be secondary to NMOSD. A comprehensive immune function and bone marrow evaluation might be necessary if abnormal blood cells are found while managing NMOSD.