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Case Reports
. 2019 Jan 24;2019(1):omy111.
doi: 10.1093/omcr/omy111. eCollection 2019 Jan.

The mystery of 'saturation gap': a case of dapsone-induced methaemoglobinemia in a pregnant mother with leprosy

Andy Sing Ong Tang  1 , Siaw Tze Yeo  1 , Yeon Chiat Teh  1 , Wee Meng Kho  2 , Lee Ping Chew  3 , Pubalan Muniandy  2
Affiliations
Case Reports

The mystery of 'saturation gap': a case of dapsone-induced methaemoglobinemia in a pregnant mother with leprosy

Andy Sing Ong Tang et al. Oxf Med Case Reports. .

Abstract

Limited data regarding methemoglobinemia in pregnancy, particularly secondary to dapsone is available up to date. We report a case of dapsone-induced methemoglobinemia in a pregnant mother with multibacillary leprosy who presented with fever, productive cough and cyanosis of 2 days duration 2 weeks after multidrug therapy was commenced. On examination, she had central cyanosis with low oxygen saturation (SpO2 = 84-88%). Arterial blood gas analysis showed PO2 of 111 mmHg and SO2 of 98 mmHg. Patient was administered 100% oxygen inhalation, but there was no improvement in cyanosis. Vitamin C (1000 mg/day) was prescribed. Dapsone was replaced by ofloxacin 200 mg twice daily. There was a gradual increase in SpO2 level. She delivered a healthy baby. In conclusion, clinicians should be aware of the side effects of dapsone and know how to promptly manage any undesirable events. Ofloxacin is a safe and feasible alternative in replacement of dapsone in pregnancy.

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Figures

Figure 1:
Figure 1:
Hypoaesthetic annular plaques on forearm (left) and back (right).
Figure 2:
Figure 2:
Cyanosis evident on initial presentation.
See this image and copyright information in PMC

References

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