Unilateral Phrenic Nerve Palsy: A Rare Manifestation of Vincristine Neurotoxicity

Excerpt

A 4-y-old girl was diagnosed with B precursor acute lymphoblastic leukemia. The child was severely malnourished weighing 10 kg (<3rd centile). Systemic examination revealed no evidence of central nervous system infilteration or pre-existing neuropathy. Biochemical investigations revealed hypoalbuminemia (serum albumin 1.0 mg/dL). Patient was treated with MCP_841 protocol [1]. Accordingly child received prednisolone (40 mg/m²⁾, L-asparaginase (6,000 U/m²), vincristine (1.4 mg/m²), daunorubicin (30 mg/m²) with weekly intrathecal methotrexate during induction. Four days after the fourth vincristine dose, child was noted to have tachypnea. There was no fever, cough, coryza and no evidence of congestive heart failure. On neurological examination there were no cranial nerve palsies or any motor deficits, but deep tendon reflexes were not elicitable. A chest radiograph revealed raised right dome of diaphragm with no evidence of mediastinal lymphadenopathy (Fig. 1). A possibility of vincristine- induced neurotoxicity was considered. Nerve conduction velocity test revealed axonal degeneration in lower extremity. Further vincristine was omitted from the treatment protocol. Child was started on oral pyridoxine and pyridostigmine and tachypnea gradually improved, but did not return to normalcy. Presently child is in maintenance phase of therapy without vincristine and is in remission.

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