Isolated invasive fungal sphenoid sinusitis-induced extensive bone erosion and severe meningoencephalitis: diagnosis and multidisciplinary management

Background

Fungal infection of the paranasal sinus is generally classified into different types based on the histological features according to the diagnosis criteria of deShazo et al;1 2 allergic, chronic non-invasive (fungus ball), chronic invasive, granulomatous invasive and acute fulminant invasive fungal infection. In addition to this classification, other types such as semi-invasive fungal infection3 and saprophytic colonisation4 have been also suggested in the literature.

The sphenoid sinus is surrounded by important structures such as the cavernous sinus, optic nerve, internal carotid artery, cranial nerves, pituitary gland and orbital apex. Thus, making sphenoid invasive fungal sinusitis (IFS) more aggressive and dangerous than on other paranasal sinuses.5

Differentiation between acute and chronic IFS depends on the speed of progression; according to Chakrabarti,6 acute lasts <4 weeks in immunocompromised patients and chronic for >3 months.

We report a case of isolated sphenoid IFS in a healthy immunocompetent patient. The IFS induced an extensive bony erosion of the sinus walls, complicated by cerebrospinal fluid (CSF) leak and severe fungal meningoencephalitis. Clinical manifestations, radiological and histological findings, medicosurgical management, outcomes and follow-up are documented.

Case presentation

A woman in her 60s was admitted to the emergency department for suspected epileptic seizures in the context of right-sided headache lasting for 5 days. She was in good general health, and her medical background showed neither immunosuppressive conditions nor previous sinus surgery. There was no history of sinusitis or any sphenoid sinus infection’s disease in the past. No history of epilepsy, head trauma or intake of any medications or drugs. There was no fever.

She presented repetitive episodes of fixed gaze and decreased consciousness lasting 10–20 s. She reported visual hallucinations with complex geometrical forms and an oppressive feeling near the temporal or occipital lobe. Otherwise, her neurological exam was initially unremarkable. The EEG confirmed seizure originating from the right temporal lobe.

Radiological workup by CT angiography of the brain showed multiple zones of hypodense collections in the subdural space with mass effect on the cerebral parenchyma (figure 1A) and complete opacification of the right sphenoid sinus with central calcifications and extensive bony-wall erosion. No signs of intracranial hypertension. MRI of the brain showed encephalitis foci in the right parahippocampal, right mid-frontal and left parietal region (figure 1B–E). 3-D CT reconstruction showed multiple zones of bony erosion of the right sphenoid sinus, the lateral wall in contact with internal carotid artery, posterior and superior walls in height of the right clivus and focal erosion at the floor of the optic nerve (figure 1F–G).

The patient was hospitalised in the neurology department, where an extensive workup showed neither systemic infection nor immunosuppression. A lumbar puncture was pathological and revealed a mild pleocytosis with lymphocytes predominance (leucocytes 6.3/x 10⁹/L including 96% of lymphocytes, erythrocytes 355/µL, proteins 1130 mg/L and normal glucose value at 4.2 mmol/L). General bacteriological, anaerobic and fungus culture was negative.

Prompt surgical drainage of the right sphenoid sinus was performed via a transnasal endoscopic approach, using a 3-D navigation system. Nasal endoscopic evaluation during the surgery showed normal appearance of the nasal mucosa with no presence of purulent secretions or any other inflammatory signs in both nasal cavities. After complete drainage of the sinus, a large area of bone erosion at the lateral sinus wall was observed (figure 2A,B). The microbiological analysis by direct microscopic exam and after culture of samples taken from the contents of the sinus were positive for Aspergillus fumigatus and Staphylococcus epidermidis.

Multiple intravenous and oral treatments were administrated with antibiotics (Fortam, meropenem and clamoxycyline) and antifungal (amphotericin B and voriconazole). The antibiotic treatment was adapted according to the results of the antibiograms. Extensive bony erosion allowed for a sinus-meningeal communication with CSF leakage confirmed by B2-transferrin analysis. In order to protect the internal carotid artery, second sinus surgery was performed 2 weeks after the first sinus drainage. Fat grafts were harvested from the periumbilical area with fascia lata graft harvested from the right lateral thigh. The surgical procedure was performed by transnasal endoscopic approach, using the 3-D navigation system. The sphenoid sinus was plugged in three layers, and the grafts were fixed using adhesive tissues (figure 2C–F). The postoperative care was simple without complications.

During her hospital stay, the seizures became more complex with forced lateral gaze deviation to the left and right facial and arm twitching. She had several focal status epilepticus despite several antiepileptic drugs. Seizures were eventually controlled with levetiracetam, lacosamide, valporic acid and clobazam. The various EEG performed during hospitalisation showed a marked improvement. Different radiological evaluation by MRI and CT scan of the brain showed significant improvement of the encephalopathic foci and favourable aspect of the right sphenoid sinus.

The patient was discharged after hospitalisation of 49 days. The antifungal treatment by voriconazol was continued for an additional 6 months. Antiepileptic therapy by pregabaline 100 mg two times per day and levetiracetam 1 g two times per day was also continued.

Follow-up at 6 months showed absence of rhinology symptoms, nasal fibroendoscopy demonstrated good aspect and well integration of the grafts with complete sealing of the right sphenoid sinus. She experienced some focal autonomic and cognitive seizures during an attempt of antiepileptic drugs. She is currently seizure-free under three antiseizure drugs. After several months of rehabilitation, she was able go home and live with her husband. She is independent for daily activities but unable to work. She kept a mild anterograde memory impairment. She does not remember the first 3 months of her illness and suffers a degree of retrograde amnesia.

Outcome and follow-up

Surgical drainage of the right sphenoid sinus combined by medical treatment allowed to good local control of the fungal infections disease.

Plugging of the right sphenoid sinus was performed to protect the internal carotid artery and by using several types of graft.

Follow-up at 6 months showed free rhinology symptoms and good aspect of the right sphenoid sinus.

Neurology outcomes were favourable with regression of the meningoencephalitis.

Evolution of the epileptic seizures was favourable under several medication.

Neurology follow-up at 6 months showed free epileptic seizures, only minor sequel with mild anterograde memory impairment.