Dapsone-induced methemoglobinemia in renal transplant recipients: more prevalent than previously thought.

BACKGROUND: After an outbreak of Pneumocystis pneumonia (PCP) in our nephrology unit, dapsone was used as the second-line chemoprophylactic agent. Dapsone is the most common cause of drug-induced methemoglobinemia (MHb). Its prevalence is poorly described in the renal transplant population. Because dapsone is excreted by the kidneys, we hypothesized that the rate of MHb in these patients would be higher than previously reported. We aimed to describe the demographics, risk factors, and presenting features of MHb in these renal transplant patients. METHODS: Twenty-six transplant recipients commenced on dapsone for chemoprophylaxis against PCP from February to September 2011. All patients had normal glucose-6-phosphate dehydrogenase levels before treatment. Characteristics of patients with MHb were compared with those of the rest of the cohort to determine potential risk factors. RESULTS: Twelve (46%) patients developed MHb (levels 6.4 ± 4.1%). Six (50%) of the patients with MHb were asymptomatic on presentation. Cases had a mean drop in hemoglobin of 19 ± 7%. MHb led to five admissions (median length of stay 5 days, range 1-10 days). MHb level showed a strong correlation with the length of stay (correlation coefficient 0.762, P = 0.002). CONCLUSION: This is the highest reported prevalence of MHb, to our knowledge, in patients receiving dapsone, and its use led to significant hospitalization in this population. This study raises concerns about the use of dapsone as chemoprophylaxis in renal transplant recipients.

Investigation of a cluster of cutaneous aspergillosis in a neonatal intensive care unit.

Between December 2007 and July 2008, three neonates in a neonatal intensive care unit (NICU) in Salford, UK, were diagnosed with primary cutaneous aspergillosis (PCA) due to Aspergillus fumigatus. The first PCA case, in December 2007, developed multi-organ failure leading to death within a short time frame: the other two cases survived after treatment with intravenous antifungal therapy followed by oral posaconazole. Air, surface, and water samples were collected within the NICU and from the incubators that were occupied by the neonates. All recovered fungal isolates were confirmed as A. fumigatus by sequencing the beta-tubulin region. Microsatellite strain typing demonstrated genotypically related A. fumigatus isolates from the neonates and the humidity chambers (HCs) of the neonates' incubators, suggesting that the source of the infection may have been the HCs/incubators used in the NICU. Aspergillus strain typing may be a useful tool in clinical outbreak settings to help understand the source of exposure and to design targeted environmental interventions to prevent future infections.

Necrotising orbital cellulitis.

PURPOSE: To report 2 cases of severe necrotising orbital cellulitis which illustrate the need for aggressive surgical management to prevent blindness. METHODS: The case records of 2 patients with necrotising orbital cellulitis were reviewed. RESULTS: Both patients had orbital cellulitis associated with sinusitis. Each case was characterised by the rapid development of severe systemic toxicity, extensive soft tissue necrosis and abscess formation. One patient developed panophthalmitis and the eye had to be eviscerated. The other patient underwent repeated surgical drainage of multiple orbital abscesses. This led to resolution of the infection and preservation of vision. CONCLUSIONS: Atypical rapidly progressive necrotising orbital cellulitis may occasionally be encountered. In such cases, aggressive surgical drainage of orbital abscesses is crucial to prevent blindness and death.