Rhinocerebral mucormycosis refers to an uncommon form of invasive fungal sinus infection.
The presentation can vary, ranging from exophthalmos, rhinorrhoea, and ophthalmoplegia with loss of visual acuity and peripheral facial palsies occurring rarely4.
It originates in the paranasal sinuses and can frequently invade to orbital and cerebral regions. If detected and treated early, involvement can be limited to the nasal cavity and paranasal sinuses.
It is caused by fungi of order Mucorales which can include Mucor, Rhizopus, and Absidia species. The fungi temselves are ubiquitus, subsisting on decaying vegetation and diverse organic material 12. Given the opportunity, fungal spores can invade the nasal mucosa (which are often not phagocytised due to poor immune response). They then germinate, forming angioinvasive hyphae that cause infarction of the involved tissue, giving in a “dry” gangrene appearance.
- diabetics: especially those with poor control 1-3
- immunocompromised states
Can show varying degree of sinus opacification with most having a tumefactive nature 6. They generally demonstrate a rim of soft-tissue thickness along the paranasal sinuses. Complete sinus opacification, air-fluid levels and obliteration of the nasopharyngeal tissue planes can also occur.
MRI sinuses - brain
Reported signal characteristics include
- T1 (non contrast): isointense lesions relative to brain in most cases (~80%) 5
- variable with around 20% of patients showing high T2 signal 5.
- fungal elements themselves tend to have low signal on T2
- T1 C+ (Gd): the devitalised mucosa appears on contrast-enhanced MR imaging as contiguous foci of nonenhancing tissue : this gives a black turbinate sign 10.
Treatment and prognosis
The condition in general carries high morbidity. Management options include reversal of immunosuppression, systemic amphortericin B and surgical debridement in selected cases. Untreated cases can rapidly progress and can be aggressive 7-8. Complications associated with wider intracranial extension can be potentially fatal 9-11.
- orbital spread
- intracranial extension
- vascular thrombosis (from extension): including the cavernous sinus thrombosis 10
- subsequent infarction:
- 1. Rupp ME. Images in clinical medicine. Rhinocerebral mucormycosis. N. Engl. J. Med. 1995;333 (9): 564. doi:10.1056/NEJM199508313330906 - Pubmed citation
- 2. Gamba JL, Woodruff WW, Djang WT et-al. Craniofacial mucormycosis: assessment with CT. Radiology. 1986;160 (1): 207-12. doi:10.1148/radiology.160.1.3715034 - Pubmed citation
- 3. Ferguson BJ. Mucormycosis of the nose and paranasal sinuses. Otolaryngol. Clin. North Am. 2000;33 (2): 349-65. Pubmed citation
- 4. Mbarek C, Zribi S, Khamassi K et-al. Rhinocerebral mucormycosis: five cases and a literature review. B-ENT. 2011;7 (3): 189-93. Pubmed citation
- 5. Herrera DA, Dublin AB, Ormsby EL et-al. Imaging findings of rhinocerebral mucormycosis. Skull Base. 2009;19 (02): 117-25. doi:10.1055/s-0028-1096209 - Free text at pubmed - Pubmed citation
- 6. Horger M, Hebart H, Schimmel H et-al. Disseminated mucormycosis in haematological patients: CT and MRI findings with pathological correlation. Br J Radiol. 2006;79 (945): e88-95. doi:10.1259/bjr/16038097 - Pubmed citation
- 7. Deshpande AH, Munshi MM. Rhinocerebral mucormycosis diagnosis by aspiration cytology. Diagn. Cytopathol. 2000;23 (2): 97-100. Pubmed citation
- 8. Peterson KL, Wang M, Canalis RF et-al. Rhinocerebral mucormycosis: evolution of the disease and treatment options. Laryngoscope. 1997;107 (7): 855-62. Pubmed citation
- 9. Saedi B, Sadeghi M, Seilani P. Endoscopic management of rhinocerebral mucormycosis with topical and intravenous amphotericin B. J Laryngol Otol. 2011;125 (08): 807-10. doi:10.1017/S0022215111001289 - Pubmed citation
- 10. Safder S, Carpenter JS, Roberts TD et-al. The "Black Turbinate" sign: An early MR imaging finding of nasal mucormycosis. AJNR Am J Neuroradiol. 2010;31 (4): 771-4. AJNR Am J Neuroradiol (full text) - doi:10.3174/ajnr.A1808 - Pubmed citation
- 11. Peterson KL, Wang M, Canalis RF et-al. Rhinocerebral mucormycosis: evolution of the disease and treatment options. Laryngoscope. 1997;107 (7): 855-62. Pubmed citation
- 12. Thomas S, Singh VD, Vaithilingam Y et-al. Rhinocerebral mucormycosis-a case report. Oral Maxillofac Surg. 2012;16 (2): 233-6. doi:10.1007/s10006-011-0292-7 - Pubmed citation
Infections of the central nervous system
- classification by aetiology
- eastern equine encephalitis
- enterovirus rhomboencephalitis
- flavivirus encephalitis
herpes virus family
- herpes simplex virus 1 (HSV-1) encephalitis
- herpes simplex virus 2 (HSV-2) encephalitis
- varicella zoster virus (VZV) encephalitis
- Epstein-Barr virus (EBV) encephalitis
- cytomegalovirus (CMV) encephalitis
- human herpesvirus 6 (HHV-6) encephalitis
- HIV CNS manifestations
- HTLV-1-associated myelopathy
- JC virus
- measles encephalitis
- Nipah virus (NiV) encephalitis
- rabies encephalitis
- CNS listeriosis (Listeria monocytogenes)
- CNS nocardiosis (Nocardia spp)
- CNS tuberculosis (Mycobacterium tuberculosis)
- Lyme disease (Borrelia burgdorferi)
- neurosyphilis (Treponema pallidum)
- Rocky Mountain spotted fever (Rickettsia rickettsii)
- cerebral amoebiasis
- cerebral malaria (Plasmodium falciparum)
- cerebral sparganosis (Spirometra mansonoides)
- neurocysticercosis (Taenia solium)
- neurohydatidosis (Echinococcus spp)
- neurotoxoplasmosis (Toxoplasma gondii)
- others or those with possible infectious aetiologies
- classification by location
- meninges and ventricular system
- brain parenchyma, brainstem, and spinal cord
- classification by aetiology