Acute methemoglobinemia with hemolytic anemia following bio-organic plant nutrient compound exposure: Two case reports

Refractory Methemoglobinemia Secondary to Topical Dapsone With Subsequent Autoimmune Hemolytic Anemia

We present a case of refractory methemoglobinemia with subsequent autoimmune hemolytic anemia in a young female after two days of topical dapsone use. A 15-year-old female with no known genetic risk factors was found to have a methemoglobinemia concentration of 37.1% after presenting with cyanosis, dyspnea, tachycardia, and oxygen saturation of 88% on 15 L of oxygen via a non-rebreather mask. Despite treatment with methylene blue, her methemoglobin concentrations continued to spike, requiring additional doses of methylene blue in addition to ascorbic acid and cimetidine. After discharge on the fourth day, she presented to another hospital with similar symptoms and was again found to have methemoglobinemia before developing autoimmune hemolytic anemia. This patient had no known underlying risk factors, including a normal BMI, normal renal function, two negative glucose-6-phosphate-dehydrogenase (G6PD) deficiency tests, and surprisingly a negative Coombs test. Although rare, particularly in the setting of topical dapsone use, methemoglobinemia remains an important consideration in the differential diagnosis of cyanosis and hypoxia, with early recognition by the emergency medicine physician being imperative for good patient outcomes.

Anemia That Presented with Desaturation: A Focus on Core Concepts

Background. Methemoglobinemia is a potentially life-threatening condition which presents with cyanosis and characteristic “chocolate-coloured blood.” Although a co-oximetry would give a prompt diagnosis, there have been multiple reports of misdiagnosing this treatable condition—from being diagnosed as sepsis to asthma and even being operated for “ruptured ectopic pregnancy.” Here, we report a case which presented without the classical signs of poisoning and methemoglobinemia—without vomiting, cyanosis, or chocolate-coloured blood. We also discuss the common misconceptions regarding anemia physiology and the pitfalls in diagnosing this condition and warn the reader regarding the reflexive use of antidotes like methylene blue. Case Presentation. A well-grown 3-year old boy presented with an acute history of irritability, cola-coloured urine, and desaturation on examination. The child was pale, with tachypnoea and in failure. Blood smear was suggestive of severe hemolytic anemia. Methemoglobinemia was diagnosed on co-oximetry. By focussing on physiologic principles of management rather than a specific antidote, the child was discharged home, well and active within 3 days of intensive care admission.

Determination of Median Lethal Concentration (LC50) and Nitrite Accumulation in the Blood and Tissue of Blood Cockle (Tegillarca granosa, Linnaeus 1758)

This study aimed to determine the nitrite toxicity of blood cockle Tegillarca granosa, with the objectives being to identify the median lethal concentration (LC50) and the accumulation level of nitrite in Tegillarca granosa, and to determine the relationship of nitrite accumulation with mortality percentage. The levels of LC50 and accumulation of nitrite were determined after 72 h of exposure to different nitrite concentrations (0, 0.5, 1.0, 1.5, and 2.0 mg/L). Nitrite accumulation was analysed using Method 8153 and a DR2800 spectrophotometer (HACH, Loveland, CO, USA). LC50 was identified at 1.53 mg/L, and nitrite accumulated in the ranges of 0.012 to 0.106 mg/L wet weight and 0.002 to 0.089 mg/L wet weight in the blood and soft tissue samples, respectively. Accumulation concentration in both tissue and blood cells increased proportionally with the exposure concentration, and had a strong positive relationship with the percentage of mortality. Our findings suggest that prolonged exposure of nitrite led to accumulation in the blood and tissues and caused cockle mortality.