RCM represents one-third to one-half of all cases of Zygomycosis. The process originates in the nose and paranasal sinuses following inspiration of fungal spores. It is estimated that 70% of the cases of rhinocerebral zygomycosis occur in the setting of DKA (7). Disease starts with symptoms consistent with sinusitis. Low-grade fever, dull sinus pain, drainage, and soft-tissue swelling are initially seen, followed in a few days by double vision, increasing fever, and obtundation. Examination reveals a unilateral generalized reduction of ocular motion, chemosis, and proptosis. Facial skin adjacent to paranasal sinuses may be invaded by direct extension, turning progressively red, purple, and black. Fever, decreased vision, and facial swelling are the most common complaints in the first 72 hours of the disease (6). Other common complaints include facial pain and nasal congestion or discharge. Headache was found early in the disease in only 25% of patients in one large study but may be a common late finding.
Schwartz noted that these nerve abnormalities are often consistent with orbital apex syndrome (unilateral ptosis, proptosis, visual loss, complete ophthalmoplegia, and ophthalmic and maxillary nerve anesthesia and anhidrosis) (11). Most cases of orbital apex syndrome are due to mucormycosis or Aspergillus, and visual loss is usually irreversible. In contrast with typical bacterial orbital cellulitis, patients with RCM may have minimal preseptal lid erythema, more pain in the forehead or temple than in the eye, and early onset of decreased sensation in the first and second divisions of cranial nerve V. The facial edema associated with RCM may be confused with periorbital cellulitis. The periorbital edema described for RCM is soft, cool, and nontender, differentiating it from the warm, tender, taut edema of cellulitis (9). Mucormycosis can be further distinguished from cellulitis by examining the character of the ptosis, if present; RCM produces a paralytic ptosis in which the eyelid can be raised easily by the examiner, whereas the edematous ptosis of cellulitis is resistant to opening. Altered mental status may be the only finding in some patients, and this disorder should be considered particularly in diabetic patients with altered mental states, who do not improve after 24 to 48 hours with correction of electrolyte abnormalities. Abramson et al. specifically noted a "characteristic" presentation that combines some of the most common findings: a dark, necrotic epistaxis ipsilateral to facial pain and soft periorbital swelling (9).
The disease may become rapidly progressive, extending into neighboring tissues. Involved tissues become red, then violaceous, and finally black as vessels are thrombosed and the tissues undergo necrosis. Extension into the periorbital region of the face and ultimately into the orbit is often found, even at presentation. Periorbital edema, proptosis, and tearing are early signs of orbital involvement. Ocular or optic nerve involvement is first suggested by pain, blurring, or loss of vision in the infected eye. Cranial nerve palsies may also be seen. Extension from the sinuses into the mouth often occurs, producing painful, black, necrotic ulcerations into the hard palate, which are sharply delineated and respect the midline. A bloody nasal discharge is generally the first sign of that the disease has invaded through the nose and sinuses and into the brain. Patients may demonstrate an altered mental state due either to ketoacidosis or to CNS invasion. Specifically, coma may be due to direct invasion of the frontal lobe.
Once the eye is infected, fungal disease can readily progress up the optic nerve, again gaining access to the CNS. Fungal invasion of the globe or ophthalmic artery leads to blindness. Angioinvasion is often seen and may result in systemically disseminated disease. Decidedly uncommon forms of rhinofacial disease published in the literature include isolated sinusitis and calcified fungal ball of the sinus. Early cases with rhinocerebral zygomycosis were almost uniformly fatal. There is still a high mortality rate with rhinocerebral disease, but curative interventions have been made with early diagnosis and aggressive surgical and antifungal treatment. The nature of the underlying disease is the most important determinant of survival, with up to 75% of immunocompetent individuals surviving in some series, compared to 60% of diabetics or 20% of individuals with other systemic disease achieving cure (6).
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