Mucormycosis

A 44-year-old woman with a 20-year history of poorly controlled diabetes mellitus presents with headache and unilateral proptosis. The patient is febrile and appears toxic. Her serum glucose level is 640 mg/dL. An urgent CT scan of the head reveals a retroorbital abscess and severe opacification of the frontal and ethmoid sinuses.
Which of the following organisms is most likely responsible for this infection?

• a. Cryptococcus neoformans
• b. Mucormycosis
• c. Mycobacterium tuberculosis
• d. Toxoplasma gondii
• e. Listeria monocytogenes
• f. Staphylococcus epidermis

The answer is (b).
Mucormycosis is a rare fungal disease (Rhizopus species are the most common causative organisms ) limited to persons with preexisting illness and may be seen in poorly controlled diabetic patients. Severe infection of the facial sinuses, which may extend into the brain, is the most common presentation. Patients present with fever, nasalcongestion, sinus pain, diplopia, and coma.
Physical examination may reveal a necrotic nasal turbinate, reduced ocular motion, proptosis, and blindness. CT scan or MRI will reveal the extent of sinus involvement prior to surgery.

Postmortem photograph of a woman with diabetes and left rhinocerebral mucormycosis complicating ketoacidosis. Rhizopus oryzae was the causative organism. Note the orbital and facial cellulitis and the black nasal discharge. (Courtesy of A. Allworth, MD, Brisbane, Australia)