What is sphenoid sinusitis?

What is sphenoid sinusitis?

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Sphenoid sinusitis – or sphenoiditis – corresponds to the inflammation of the sinuses of the same name, located at the back of the nose, above the nostril wings. This condition, almost exclusively of bacterial origin, can cause intense pain behind the eyes and headaches. What are the possible complications of this type of sinusitis? How to treat it? The answers of Dr Raphael Hadjedj, ENT doctor and head and neck surgeon.

What is the sphenoid sinus?

The sphenoid sinus is a paired air cavity located in the body of the sphenoid bone, central and posterior to the other three sinuses.

It is divided into two parts – right and left – separated by a thin bony septum. These two sinuses are not present at birth, and only appear around the age of 10, to complete their development after puberty. They are located in close proximity to important structures such as the optic nerve and the internal carotid artery. They communicate with the nasal cavity through the sphenoid ostium located in a recess called the “ethmoidosphenoidal recess”.

The two sphenoid sinuses can vary greatly in size and shape and are rarely symmetrical. Sphenoid sinusitis, also known as sphenoiditis, is the inflammation of these sinuses. When only one of the two sphenoid sinuses is affected, we speak of unilateral sphenoid sinusitis.

Pain, fever, headache: what are the symptoms?

The main symptom of sphenoid sinusitis is headache. “It is generally located at the back of the head or behind the eye and tends to increase when the head is tilted forward.” describes Dr Hadjedj. These headaches can intensify at night and resist usual analgesics.

These headaches can be accompanied by a fever often above 38.5°C.

A runny nose, which is rarer, occurs mainly at the back of the nose. In some cases, vision problems may also appear.

What are the causes of sphenoid sinusitis?

Sphenoid sinusitis is generally the result of a bacterial superinfection, and is therefore almost never of viral origin. Nasopharyngitis and colds, which cause inflammation of the lining of the nose and sinuses, are often the cause of this disease. Finally, in a few rare cases, sphenoid sinusitis is due to a fungal infection (by a fungus), we then speak of aspergillary sinusitis, which is chronic sinusitis.

There are nevertheless some aggravating risk factors, including:

  • Smoking, which irritates and inflames the nasal mucous membranes;
  • Allergies, which can cause inflammation of the sinuses and facilitate infection;
  • Diseases that weaken the immune system, such as diabetes or AIDS, which make the body less able to fight infections.


The diagnosis of sphenoid sinusitis is initially made on the basis of clinical symptoms such as pain behind the eye and intense headaches, often worse at night.

However, to confirm the diagnosis and assess the severity of the infection, medical imaging tests are generally necessary.

Endoscopy may be offered to look for the presence of pus in nasal secretions” explains the ENT doctor.

The CT scan is then the reference method to visualize the opacity of the sphenoid sinus and identify possible damage to the posterior ethmoidal cells. If in doubt, an MRI may be offered to identify possible complications.

All this information collected allows the specialist doctor to make an accurate diagnosis and plan the most appropriate treatment.

How to treat sphenoid sinusitis?

Which antibiotic: augmentin, ciflox, cefpodoxime or amoxicillin?

In the presence of sphenoidal sinusitis, it is recommended to start with a simple monoantibiotic treatment with Augmentin® (1g 3 times a day) or Cefpodoxime_proxetil® (200mg 2 times a day). “If symptoms persist for 48 hours, it is more appropriate to switch to dual antibiotic therapy Augmentin® in combination with Ciflox®“But simple amoxicillin, usually offered for the treatment of bacterial maxillary sinusitis (the most common), is not recommended in cases of sphenoiditis because the spectrum is too narrow.

A control scan is always carried out 2 to 3 weeks after the start of treatment, to check that the antibiotics have been effective.


Surgery is resorted to when sphenoid sinusitis is linked to an identified anatomical problem or when drug treatments are not sufficient to resolve the inflammation. The commonly considered surgical procedure is sphenoidotomy, which involves opening the sphenoid sinus in order to improve ventilation and drainage. Electrosurgical septoplasty combined with turbinoplasty can be considered in the event of anatomical nasal obstruction. These interventions generally take place under general anesthesia.

How long does sinusitis with antibiotics last?

The duration of antibiotic treatment for sphenoid sinusitis varies depending on the severity of the infection. Generally, the recommended duration of antibiotic treatment is 7 to 10 days. “In some cases, when the infection is severe, treatment can last up to 15 days” specifies Dr. Hadjedj. Whatever happens, it is essential to respect the duration of the treatment prescribed by the doctor, even if the symptoms seem to improve sooner.

What are the complications?

Due to its proximity to the brain as well as certain important nerves and blood vessels, untreated sphenoid sinusitis can lead to serious complications.

Possible complications are:

  • Serious neurological complications, such as meningitis or intracerebral abscess, due to spread of infection to the brain, are rare but possible” indicates the ENT,
  • Bone infections, which may require surgery;
  • Visual disturbances, such as decreased visual acuity, oculomotor nerve paralysis, or eyelid swelling.

To avoid these complications, it is therefore essential to quickly consult a healthcare professional if you have symptoms of sphenoid sinusitis.