Rhinocerebral mucormycosis: a rare but life-threatening opportunistic infection in diabetic patients

Backgrounds/Aim

Mucormycosis is an uncommon necrotizing infection caused by fungi within the class Zygomycetes and the order Mucorales. It mainly occurs in immunocompromised states, including diabetes, with the rhinocerebral disease being the most common type of mucormycosis seen in patients with diabetes. The aim of this study is to document the pathogenesis and clinical presentation of rhinocerebral mucormycosis as well as to emphasize the need of early recognition and aggressive treatment of the disease, as it is the only chance to increase the survival rate.

Methods

From the review of the international literature, it is obvious that the disease originates in the nasal/sinus mucosa after inhalation of fungal spores and takes rapidly progressive course extending to neighboring tissues, including the orbit and sometimes the brain. The pathogenesis of the disease includes the reduced iron- binding capacity to transferrin, due to the acidic milieu (in case of diabetic ketoacidosis), that results in increased free iron and therefore promotes the growth of the fungus. Patients typically present with malaise, retro-orbital headache, fever, dark blood-tinged rhinorrhea and a characteristic black eschar in the oral and nasal cavity. In the diagnostic work-up, the histologic section reveals wide, non-septate hyphae with right-angled branching. Sinus and blood cultures are less important, however they should not be omitted. Imaging studies (CT, MRI) are important in order to evaluate the extent of the disease.

Results-conclusion

Treatment of rhinocerebral mucormycosis should consist of prompt control of hyperglycemia and ketoacidosis, aggressive surgical detriment of involved tissue and administration of parenteral amphotericin B.

A high index of suspicion is needed, in appropriate clinical settings, to diagnose and aggressively treat this infection in view of the high mortality rate for susceptible patients.