Mucormycosis is inherently found in soil and decomposing plants . The main pathogenesis form is hematogenous dissemination (angio-invasion) due to its adhering ability and invade the endothelium of blood vessels neighbors, allowing it to invade any organ system and represents the third fungal infection angioinvasive most common .
The disease can be present in the lung tissue, gastrointestinal, rhino-orbital-cerebral and distributed in the skin . Rhinocerebral and pulmonary forms account for about 54% and 60% of cases respectively. The primary site of infection differs with the various genders included in the Mucorales order and the underlying systemic condition of the organism . It is a rare condition that arises more commonly in people with compromised immunity, such as in transplanted solid organs, leukemia, lymphoma, myeloma, diabetes mellitus, extreme burns, kidney dysfunction, liver cirrhosis, antineoplastic chemotherapy, chronic corticosteroid use, or immunosuppressive treatment .
Nithyanandam et al. , describes a mortality rate of approximately 40% in diabetics with rhinocerebral mucormycosis and a similar survival rate for rhinocerebral disease in patients with hematological neoplasms . Mucormycosis rarely develops in other cases of immunosuppression such as AIDS or in immunocompetent patients .
In rhino-orbital-cerebral mucormycosis, the most common complaints are purulent or bloody rhinorrhea (most of the time unilateral), fever, headache, and general malaise. Fever is variable and may be absent in up to half of cases . When orbital involvement occurs, complaints are eyelid edema, diplopia and decreased visual acuity. On physical examination, unilateral or bilateral rhinorrhea, proptosis, chemosis, periorbital cellulitis, alteration of the intrinsic and extrinsic ocular motricity and amaurosis can be observed. Nasofibrolaryngoscopy can demonstrate necrotic lesions in the nasal mucosa .
If left untreated, the infection typically progresses from the ethmoid sinus to the orbit, causing loss of extraocular muscle activity and exophthalmos. It is very important to keep in mind that, if mucormycosis is suspected, initial and empiric therapy with pollinated antifungal should begin before the diagnosis is confirmed, rather than waiting for a long sequence of diagnostic tests to be completed .
Rhinocerebral presentation of Mucormycosis remains the most common clinical form of the disease, accounting for half of all cases . About 70% of cases of rhinocerebral mucormycosis (occasionally referred to as craniofacial) are found in diabetic patients in ketoacidosis , but it also occurred in patients who received solid organ transplantation or those with prolonged neutropenia . Rhinocerebral disease is a growing problem in patients undergoing hematopoietic stem cell transplantation  and in these cases, it has been widely associated with the use of steroids for graft-versus-host disease. The infection can spread to the central nervous system through the orbital apex, the involvement of bony walls of the paranasal sinuses, or the cribriform plate of the ethmoid .
Risk of death increases rapidly as the fungus penetrates the skull and reaches the main intracranial vasculature. The early surgical excision of the infected sinuses and proper debridement of the retro-orbital space, in this situation, might prevent the infection from spreading to the eye, therefore preventing its need for enucleation, resulting in an exceptionally high rate of cure for patients (around 85 %) . To ensure that all necrotic tissue has been debrided and the infection has not advanced, periodic surgical exploration of the sinuses and orbit may be required .
The diagnosis is based on the association between mycological analysis, histopathology and clinical signs . Treatment development relies on the speed of diagnosis  and the implementation of surgery and antifungal therapy . From an imagery point of view, CT scan is the most commonly available diagnostic aid, yet, bone loss is also seen late in the course of infection and other tissue necrosis has already occurred.
Magnetic resonance imaging (MRI) is a very useful technique for detecting potential intradural and intracranial extensions. Perineural presence can be shown by a contrast-enhanced MRI . After all, it is very possible for patients at an early stage of the disease to have regular imaging scans, which reinforces that a surgical procedure with early biopsies, if there is clinical suspicion, is necessary for a correct diagnosis. Histological diagnosis of mucormycosis is supported by the finding of non-septate or small septate hyphae and these changes are different from that found, for example, in the stain of Aspergillus, the hyphae of which are narrower and often septate. The genus and species of the organism can be determined by growing the infected tissue in its own environment. Nevertheless, microorganisms are rarely isolated in blood, cerebrospinal fluid or sputum cultures .
The treatment of Mucormycosis is focused on multimodal therapy: application of antifungal drugs, regulation of predisposing factors (diabetes, immunosuppressive agents) and surgical debridement to eliminate infected and necrotic tissue .
The most widely used drug is Amphotericin B, classic or liposomal, in high daily doses (5 mg/kg/day) and may include an additional antifungal agent, such as Caspofungin, for 6 to 8 weeks . Posaconazole (800 mg/day) is used in a reduction therapy and can be used in combination with Amphotericin B, as this medication is highly active against some species of Mucorales. Hyperbaric oxygen can be used as adjuvant therapy, but its benefit is not yet well established .
The responsiveness of the species to drug treatment may differ considerably such that the patient receiving Amphotericin B alone is inadequate during the diagnosis time. Minutes and hours matter, and if clinical suspicion is high, work can continue immediately, even if the patient is clinically healthy because late diagnosis is correlated with adverse outcomes . Treatment success depends directly on efficacy, speed of diagnosis , and a combined approach between the surgical procedure and antifungal therapy .
Surgery (debridement) is necessary and urgent due to an immense amount of tissue necrosis arising during mucormycosis, which cannot be stopped by the death of the organism . Given the fast-growing nature of rhinocerebral mucormycosis and the substantial rise in mortality as the infection reaches the brain, diabetic patients with headaches and vision changes are candidates for early assessment with imaging and nasal endoscopy to rule out mucormycosis. Radiographic findings are below clinical progression in this disease and a negative imaging study does not provide a justification for postponing more aggressive diagnostic maneuvers (endoscopy with biopsy) if the clinical suspicion is high .
In cases where the suspicion of Mucormycosis is high, blind biopsies of the sinus mucosa and/or thickened extraocular muscles are required for a conclusive diagnosis and the endoscopic approach is the most suitable .
The nature of the underlying disease and the reversibility of immune dysfunction are also important determinants of survival. Poor prognosis factors are: (a) delay in starting treatment, (b) intracranial involvement (hemiplegia and hemiparesis), (c) palatal or orbital, as well as (d) bilateral involvement of the sinuses and (e) facial necrosis . Cerebral involvement is characterized by changes in the state of consciousness, which can cause seizures and/or hemiplegia. If occurs invasion of the cavernous sinus, fungal aneurysms of the internal carotid artery are common and generally fatal .
Mucormycosis is a rare opportunistic infection with an adverse prognosis. Very commonly, it affects those with a compromised immune system. Prevention involves environmental control, avoiding or minimizing direct contact with fungal propagules present in plants, flowers and domestic dust, and correct management of systemic impairments already present in the health of the patient.