Case report Methemoglobinemia secondary to topical silver nitrate therapyÐa case report Trong-Duo Chou a , Nicole S. Gibran b, *, Kevin Urdahl c , Eric Y. Lin b , David M. Heimbach b , Loren H. Engrav b a Department of Surgery, Tri-Service General Hospital, Taipei, Taiwan b University of Washington Burn Center, Harborview Medical Center, Seattle, WA, USA c Department of Pediatrics, University of Washington, Seattle, WA, USA Accepted 22 February 1999 Abstract Methemoglobinemia is a rare complication in individuals exposed to nitrates or nitrites. Whereas methemoglobinemia is a recognized potential complication in burn patients treated with topical 0.5% silver nitrate solution, no report of methemoglobinemia in burn patients has been present in the literature for more than 15 years. We raise consciousness about this complication with a case report of a 12-month-old child with necrotizing fasciitis resulting from a cutaneous ¯ank infection. The patient developed cyanosis 20 days after initiation of topical treatment with 0.5% silver nitrate solution. Intravenous injection of methylene blue can restore normal blood oxygenation. # 1999 Elsevier Science Ltd and ISBI. All rights reserved. Keywords: Burns; Silver nitrate; Methemoglobinemia; Dermal substitute 1. Introduction Methemoglobinemia represents a condition in which nitrite induced oxidation of the ferrous iron (Fe 2+ ) in the heme molecule to ferric iron (Fe 3+ ) results in diminished oxygen carrying capacity by the hemo- globin molecule. Whereas normal red blood cells con- tain a small amount of methemoglobin, the body regulates this level by enzymatic reduction of the hemoglobin molecule mediated by the enzyme NADH- cytochrome-b5 reductase (NADH-methemoglobin re- ductase). Several recognized chemical compounds (Table 1) [1] in the home, industry, and clinical therapy increase the rate of heme oxidation and over- whelm the capacity of red blood cells to maintain hemoglobin in the reduced state [2]. The most common toxic substances are the nitrite/nitrate family. These include sodium nitrite, amyl nitrite, nitroglycerin, nitroprusside and silver nitrate. Most of the published reports in the literature over the past 20 years have involved nitrite and nitrate exposure due to water con- tamination or meat processing. Silver nitrate solution is a common antimicrobial, used in burn centers, that has been recognized to cause methemoglobinemia. However, the last published reports of methemoglobi- nemia due to silver nitrate exposure were in 1969 [3,4]. Therefore, we felt that a case report of silver nitrate- induced methemoglobinemia would promote awareness of this unusual but real complication associated with a commonly used therapeutic agent. 2. Case report The patient was a 12-month-old female infant, who was transferred from a regional hospital to our Burn Center for treatment of an intractable infection with Burns 25 (1999) 549±552 0305-4179/99/$20.00+0.00 # 1999 Elsevier Science Ltd and ISBI. All rights reserved. PII: S0305-4179(99)00031-5 www.elsevier.com/locate/burns * Corresponding author. Dr Nicole S. Gibran, Division of Surgery, Box 359796, Harborview Medical Center, 325 Ninth Avenue, Seattle, Washington 98104, USA. Tel.: +1-206-731-2931; fax: +1-206-731- 3656. E-mail address: nicoleg@u.washington.edu (Nicole S. Gibran)