Iatrogenic Anemia (Hemolysis) Following the Use of Methylene Blue Powder in Newborn: A Case Report

Methylene blue was first described for the treatment of methemoglobinemia but practical usage of the compound for surgical purpose is common. The aim of this report is to describe a case of hemolysis in neonatal period as a potential hazard of methylene blue toxicity without presence of G6PD deficiency.
In October 2015, a 36-week GA female infant with 2.05 kg weight was delivered by cesarean section with APGAR score of 9/9 from a healthy mother, with common type esophageal atresia. She underwent surgical repair with drainage tube placement on second day of life in our subspecialty referral center, Tehran, Iran. Her blood group type was A and her mother was AB with no family history of hematologic disease. On fifth day postoperative, 2 mL of methylene blue solution that was prepared by dissolving its powder in the hospital laboratory were fed per oral for confirmation of the integrity of esophagus after repair. 8 days after methylene blue ingestion, we met suddenly the occurrence of severe anemia and hyperbilirubinemia with Hb: 6 gr/dL (post-operative Hb: 15 gr/dL) , retic count: 4.8%, total bill/direct: 20/ 0.3, indirect coombs negative ,G6PD: sufficient, ALT: 30 U/L, and AST: 66U/L. At follow-up 2 months after the initial operation, barium meal showed moderate stricture at the site of anastomosis.
We considered two main reasons for hemolysis in our patient. The first explanation is that our patient received 20 mg/kg MB as solution which was nearly 5 - 10 times more concentrated than the recommended dose. The second is that the absorption of MB from mediastinal/plural space could be more than expected. Our justification for this event is the anastomosis site stricture at follow-up that was suggestive of Methylene blue leak to mediastinal/plural space on first day after repair. Therefore, paying attention to the preparation of methylene blue solution from its powder is essential. Determination of G6PD status as a risk factor for development of methylene blue toxicity is recommended. However, G6PD with two rechecks was sufficient for our patient.