A case of methemoglobinemia after ingestion of an aphrodisiac, later proven as dapsone

Acquired methemoglobinemia: A systematic review of reported cases

INTRODUCTION

Acquired methemoglobinemia may cause cyanosis and tissue ischemia unresponsive to oxygen supplementation.

METHODS

We performed a literature search to identify cases of acquired methemoglobinemia published between 1980 and 2020. Clinical, diagnostic, and treatment details were extracted from eligible cases.

RESULTS

A total of 76 reports involving 87 cases were analyzed. The median age at presentation was 32.5 with male to female ratio of 1.6. Cyanosis and SpO₂ <90 % were reported in 82 % and 60 % of cases, respectively. Dapsone or cocaine-based anesthetics were causative in 52 % of cases; most anesthetic-related cases occurred in the peri-procedural setting. Methylene blue (MB) and red cell transfusion were given in 71 % and 10 % of cases, respectively. Compared to MB untreated patients, MB treated patients were more likely to be cyanotic (91.9 % vs 54.2 %), had higher proportions (%) and levels (g/dL) of methemoglobin (MetHb) - 33.2 % vs 15.3 % and 3.1 g/dL vs 1.2 g/dL, respectively. We found that among cyanotic cases, the median MetHb level was 3.0 g/dL (0.4-12.3 g/dL) with 74 % of values ≥ 1.5 g/dL. An SaO2:SpO₂ ratio of >1 was not universally present, but always coincided with an [SaO₂-SpO₂] delta value greater than zero.

CONCLUSIONS

Cyanosis and hypoxemia were not universal findings of acquired methemoglobinemia in our series. In addition, not all patients had cyanosis at MetHb ≥ 1.5 g/dL or an SaO2:SpO₂ ratio of >1. All those with an SaO₂:SpO₂ >1 did, however, have a delta value greater than zero - a finding not previously reported which we feel holds diagnostic value.

Case files of the medical toxicology fellowship at Banner Good Samaritan Medical Center in Phoenix, AZ: methemoglobinemia following dapsone exposure

Acquired methemoglobinemia is a common, potentially fatal syndrome that can occur as a result of exposure to numerous xenobiotics. A case report of a 14-month-old female who developed methemoglobinemia following a dapsone ingestion. The child was treated with numerous boluses of methylene blue and ultimately required a continuous infusion of methylene blue. The common causes of methemoglobinemia, as well as the underlying pathophysiology, diagnosis, and treatment strategies are discussed.

Isobutyl-nitrite-induced methemoglobinemia; treatment with an exchange blood transfusion during hyperbaric oxygenation

A young man was accidentally intoxicated with isobutyl nitrite by a threefold lethal dose. Due to nitrites' ability to change hemoglobine into methemoglobine the patient showed signs of severe hypoxia, which could not be treated by conventional means. Therefore the patient was rapidly transferred to a hyperbaric chamber. The patient was treated with pure oxygen at 283 kPa under which a blood exchange transfusion was performed. The patient fully recovered.