MKSAP quiz: Type 1 diabetes, ketoacidosis, and fungal infection

This month's quiz asks readers to evaluate a 40-year-old man admitted to the emergency department with a 1-day history of headache and epistaxis.

A 40-year-old man is admitted to the emergency department with a 1-day history of headache and epistaxis. He has had type 1 diabetes mellitus requiring insulin for 30 years and two episodes of ketoacidosis in the past year.

On physical examination, temperature is 36.0 °C (96.8 °F), blood pressure is 100/70 mm Hg, pulse rate is 120/min, and respiration rate is 22/min. There is mild proptosis of the right eye with periorbital edema and a black eschar on the inferior turbinate of the right nostril. Skin examination shows no other lesions. The remainder of the examination is normal.

Laboratory studies are consistent with diabetic ketoacidosis. Blood cultures are negative. A chest radiograph is normal.

CT of the head reveals mild proptosis of the right eye and right ethmoid and maxillary sinusitis with bony erosion. Intravenous amphotericin B is instituted.

In addition to treatment of this patient's diabetic ketoacidosis and institution of antifungal therapy, which of the following is the most important next step in treatment?

A. Add piperacillin-tazobactam
B. Add posaconazole
C. Administer hyperbaric oxygen treatment
D. Perform surgical debridement

MKSAP Answer and Critique

The correct answer is D. Perform surgical debridement. This item is available to MKSAP 16 subscribers as item 65 in the Infectious Disease section. Information about MKSAP 16 is available online. Treat mucormycosis (previously zygomycosis) in a patient with diabetic ketoacidosis.

Based on his clinical scenario and physical examination findings, this patient most likely has rhino-orbital mucormycosis (previously zygomycosis) and requires emergency surgical debridement and intravenous amphotericin B. Because of a recent change in taxonomy, the class name Zygomycetes has been replaced, and, therefore, the term “zygomycosis” is no longer appropriate. Classic manifestations of mucormycosis are sinusitis, rhino-orbital infection, and rhinocerebral infection. Following inhalation of spores, infection is initially localized to the nasal turbinates and sinuses. Infection can progress rapidly to the orbit or brain. Prompt administration of intravenous amphotericin B and aggressive surgical debridement are essential in cases of suspected mucormycosis given the high mortality rate (25% to 62%) associated with this disorder.

Piperacillin-tazobactam is a broad-spectrum β-lactam/β-lactamase inhibitor combination that is used to treat polymicrobial bacterial infections. It does not possess antifungal activity and, therefore, would not be appropriate as the next important step in managing a life-threatening fungal infection.

Oral posaconazole is a broad-spectrum azole antifungal agent that has in vitro activity against mucormycoses. This agent may have a role in step-down therapy for patients who have responded to amphotericin B or as salvage therapy for patients who have not responded to first-line treatment, but it would not be appropriate first-line treatment in this patient.

The efficacy of hyperbaric oxygen treatment of mucormycosis has not been definitively demonstrated in clinical trials. Hyperbaric oxygen is not a first-line treatment and should not be considered in this patient.

Key Point

  • Successful management of mucormycosis (previously zygomycosis) hinges on prompt administration of appropriate antifungal therapy coupled with aggressive surgical debridement.