Rhinocerebral mucormycosis : Medico-surgical emergency

Clinical History

A 32-year-old woman presented in post-partum with inaugural acidoketosis decompensation.
In spite of the improvement of the glycemic figures and the correction of the acidoketosis, the neurological status of the patient did not improve.
On clinical examination an unconscious, febrile (39 degrees) patient was found with pupils in anisocoria, right exophtalmos and plentiful, purulent secretions.

Imaging Findings

Magnetic resonance imaging (MRI) was performed and revealed extensive necrosis of the right nasal fossa, ethmoidal cells and the inner wall of the right maxillary sinus (Fig. 1), associated with a thrombosis of the right cavernous sinus and ophtalmic vein (Fig. 2).
There are also intracerebral lesions related to encephalitis (Fig. 3) and septation of the subcutaneous fat, and thickening of the underlying superficial fascia in relation with a facial cellulitis (Fig. 4).

Discussion

Mucormycosis is an infection caused by mycoses of the order of Mucorales. These organisms are anaerobic and thermoresistant [1].Gateways are multiple: inhalation of spores in the upper aerodigestive tract or inoculation at a vascular entry point or a major wound. These germs have a angioinvasive character [2], they penetrate into vessels thanks to an elastase enzyme, then the mycelian invasion causes a thrombosis of vessels, an infarction and a necrosis of tissues. There is no inter-human contamination, thus it is not necessary to isolate patients affected by mucormycosis [3].
Rhinocerebral mucormycosis is the most frequent (39 %); it manifests clinically as a sinusitis, a cellulitis with signs of parietal necrosis, or as neurological complications [4].
Cerebrofacial CT is the essential examination in rhinocerebral mucormycosis. The most often found radiological signs are osteolysis, nodular thickening of the mucous membrane of the sinus with no enhancement of the affected zones; the preantral and postantral fat may become infiltrated.
MRI estimates better the intracranial invasion and the orbital extension. Angio MRI allows to objectify the thrombosis of cavernous sinuses, internal carotid and its branches. CT or MRI images are not characteristic but highly suggestive in a diabetic in ketoacidosis. Finally, CT and MRI allow to evaluate the evolution of the disease under treatment.
The treatment is medical and surgical. It is based on the intravenous Amphotericin B (1 to 1, 5 mg / kg per day), which must be established as soon as the diagnosis is suspected [5]. The treatment duration is 12 weeks at least. The surgical resection of the necrosed tissues is essential and must be associated with medical treatment. The surgical debridement of the lesions allows to reduce the fungal burden, and allows the systemic treatment to reach the infected zones. The treatment of predisposing factors (in particular diabetes control) is essential [6].
Despite therapeutic advances, the prognosis of rhinocerebral forms of mucormycosis remains gloomy because 20 to 50% of patients die, and neurological sequelae are common [7].
This observation emphasizes the particular gravity of mucormycosis in diabetic patients. It shows the diagnostic difficulties related to the absence of specificity of clinical manifestations. It indicates the necessity of a fast confirmation of the diagnosis by the biopsy sample in order to establish adequate treatment which must be begun in the stage of diagnostic suspicion.

Differential Diagnosis List

Final Diagnosis

Rhinocerebral mucormycosis

URL:	https://www.eurorad.org/case/11497
DOI:	10.1594/EURORAD/CASE.11497
ISSN:	1563-4086