INTRODUCTION Granulomatous inflammation is a distinctive ...

emains very poor (Brad et al., 2005).
Pathology
Fungi of the order Mucorales are causes of mucormycosis. These fungi are found as ubiquitous
bread and fruit molds that thrive in soil, manure, or decaying material (Ribes et al., 2000).
Both mononuclear and polymorphonuclear phagocytes of normal hosts kill Mucorales by the
generation of oxidative metabolites and the cationic peptides defensins (Waldorf, 1989).
Hyperglycemia and acidosis are known to impair the ability of phagocytes to move toward and kill
the organisms by both oxidative and nonoxidative mechanisms. Additionally, corticosteroid
treatment affects the ability of bronchoalveolar macrophages to prevent germination of the spores
in vitro or after in vivo infection induced by intranasal inoculation (Waldorf et al., 1984)
A recently identified important clinical feature is the increased susceptibility to mucormycosis of
patients with elevated available serum iron. It has been known for two decades that patients
treated with the iron chelator deferoxamine have a markedly increased incidence of invasive
mucormycosis (Boelaert et al., 1994). Multiple lines of evidence support the conclusion that
patients in systemic acidosis have elevated levels of available serum iron, likely due to release of
iron from binding proteins in the presence of acidosis (Artis et al., 1982).
Transmission occurs through the inhalation of airborne spores, and the typical port of entry is the
sinuses. The fungus can grow rapidly, invading the orbit and brain (Metwally, 2006-7).
A hallmark of mucormycosis infections is the virtually uniform presence of extensive
angioinvasion with resultant vessel thrombosis and tissue necrosis. This angioinvasion is
associated with the ability of the organism to hematogenously disseminate from the original site of
infection to other target organs (Bouchara et al., 1996).
Infection spreads along vascular and neuronal structures and infiltrates the walls of blood vessels.
Infections cause erosion of bone through walls of the sinus and spread into the orbit and the retroorbital
area and may extend into the brain. Invasion of nerves, blood vessels, cartilage, bone, and
meninges is common. Direct invasion by fungal elements results in thrombosis and nerve
dysfunction. Advancing infection can result in cavernous sinus thrombosis, carotid artery
thrombosis, and jugular vein thrombosis. The term rhinocerebral indicates sinus involvement but
does not always mean that CNS invasion has occurred (Metwally, 2006-7).
Clinical Presentations
Rhinocerebral mucormycosis continues to be the most common form of mucormycosis, accounting
for between one-third and one-half of all cases. About 70% of rhinocerebral cases are found in
diabetic patients in ketoacidosis. More rarely, rhinocerebral mucormycosis has also occurred in
patients who received a solid organ transplant or those with prolonged neutropenia (Gleissner et
al., 2004). Recently, rhinocerebral disease has been an increasing problem in patients undergoing
hematopoietic stem cell transplantation. These cases have largely been associated with steroid use
for graft-versus-host disease (Marr et al., 2002).
The initial symptoms of rhinocerebral mucormycosis are consistent with either sinusitis or
periorbital cellulitis and include eye or facial pain and facial numbness, followed by the onset of
conjunctival suffusion, blurry vision, and soft tissue swelling. Fever is variable and may be absent
in up to half of cases; white blood cell counts are typically elevated, as long as the patient has
functioning bone marrow (Thajeb et al., 2004). If untreated, infection usually spreads from the
ethmoid sinus to the orbit, resulting in loss of extraocular muscle function and proptosis. Marked