Gradenigo Syndrome - Cause, Clinical Features, Diagnosis, and Treatment

What Is Gradenigo Syndrome?

It is a classic combination of three symptoms, which are

1. Otitis Media: There is a chronic infection of the middle ear without an intact tympanic membrane which is called suppurative otitis media.

2. Retro-Orbital Pain: There is facial pain in the retro-orbital region supplied by the frontal and maxillary branches of the fifth cranial nerve called the trigeminal nerve. This nerve is affected due to the spread of inflammation to Meckel cave (the opening through which the trigeminal nerve passes).

3. Abducens Nerve Palsy: It is paralysis of the sixth cranial nerve as secondary involvement of nerve passing through the opening in the base of the skull called the Dorello canal.

What Is the Cause of Gradenigo Syndrome?

The incidence of Gradenigo syndrome is rare after the discovery of antibiotics. It was first described by Giuseppe Gradenigo in 1904. The disease was a typical progression of partially treated or untreated otitis media. But it is now becoming relatively rare because of appropriate antibiotic use. During the pre-antibiotic era, about two to seven percent of cases with ear infections reported intracranial complications after the improperly treated ear infection. With the proper use of more powerful and effective antibiotics and more evolved and improved surgical techniques, the incidence of intracranial complications has reduced significantly to 0.04 to 0.15 percent of cases.

How Does Gradenigo Syndrome Occur?

The source of infection is the bacteria spread from the middle ear to the air cells in the mastoid (the bone just behind the ear). The air cells are composed of highly vascular marrow which has increased susceptibility to infections. Bacteria can then travel to the nearby structure like the petrous part of the temporal bone (the pyramid-shaped present at the base of the skull between the sphenoid and the occipital bone). This part of the temporal bone has several crucial structures around it, which includes the trigeminal ganglion (the collection of neuronal bodies of the trigeminal nerve) and the abducens nerve. These two structures are demarcated from the petrous part of the temporal bone only by the dura mater (the outer covering of the brain and spinal cord). So, any kind of infection and inflammation in this region will affect and damage these nerves. This can cause pain along the nerve distribution in the face and horizontal diplopia (side-to-side double vision) secondary to unilateral esotropia (inward or nasal deviation of the eye on one side).

What Are the Clinical Features of Gradenigo Syndrome?

• The typical triad of signs are :

  • Otorrhea.

  • Facial pain.

  • Horizontal diplopia.

• Other symptoms include:

  • Fever.

  • Headache.

  • Pain and tenderness in the ear.

  • Discharge from the ear.

  • Nausea and vomiting.

  • Dizziness.

  • Confusion.

  • Photophobia (sensitive to light).

  • Excessive lacrimation (production of tears).

  • Severe pain on one side of the face.

  • Diplopia (double vision).

What Is the Diagnosis of Gradenigo Syndrome?

• Patient History: A detailed investigation of patient history and clinical evaluation characterized by the classic triad of otitis media, facial pain, and abducens nerve paralysis.

• Clinical Examination: The functioning of extraocular muscles which are present outside the eyeball are checked, especially the lateral rectus muscle is checked. And in the ear, the middle ear part and tympanic membrane are checked for discharge.

• Laboratory Tests: Complete blood count is evaluated for erythrocyte sedimentation rate (ESR) and C-reactive protein levels. And fluid discharged from otorrhea (liquid discharge from the ear) is cultured for the selection of antibiotics for treatment.

• Computed Tomography (CT): It is the choice of investigation to examine petrous temporal bone to locate the lesions. It has the advantage of low false-positive (a result that shows a person has the disease when the person does not have the disease). It can also measure the extent of temporal bone pneumatization ( formation of air cavities in bone) and marrow formation.

• Magnetic Resonance Imaging (MRI): This device uses strong magnetic and radio waves to visualize the internal structures. So it can study the composition of the lesion which cannot be done by a CT scan. The need to know the composition of the lesion is significant to differentiate it from other similar conditions like osteomyelitis, cholesteatoma, and petrous apicitis and come to an accurate diagnosis, and plan the treatment accordingly.

What Is the Treatment for Gradenigo Syndrome?

• Antibiotic Therapy: High doses of antibiotics are given for the infection. It is the most common choice of treatment. If the inflammation has spread to key structures and puts them at risk of irreversible damage, performing surgery is the treatment of choice. The antibiotics used are:

  • Cephalosporins.

  • Metronidazole.

  • Penicillin.

  • Ampicillin.

  • Vancomycin.

• Surgical Therapy: Surgery is the primary form of treatment in patients who are not responding to antibiotic therapy and who are noncompliant with antibiotics. Surgeries performed are mastoidectomy and petrosectomy where the granulation tissue and dead bone tissue are removed that are formed due to the infection present in the mastoid and petrous temporal bone.

  • Mastoidectomy: A mastoidectomy surgery is started by making a retro auricular (behind the ear) incision to reach the mastoid antrum (air filled cavity) and mastoid cells. Mastoid cells bordering the sigmoid sinus and middle and posterior cranial fossa are removed using an electric burr and curette.

  • Petrosectomy: It is similar to the mastoidectomy surgery, but performed in the petrous part of the temporal bone. The dead and infectious tissue is removed and further damage to the bone like erosion and inflammation is prevented.

  • Infralabyrinthine Approach: It is another way to access the petrous temporal bone through the infra labyrinthine air cell tract present in the temporal bone. The cavity irrigation is done with saline and hydrogen peroxide after the drainage of purulent secretions.

  • Myringotomy: To drain the fluid, a cut is made in the tympanic membrane called a myringotomy.

What Are the Complications of Gradenigo Syndrome?

• Hearing loss.

• Meningitis (inflammation of the meningeal layer covering the brain and spinal cord).

• Vernet’s syndrome (spread of infection to the base of the skull).

• Sigmoid sinus thrombosis.

• Spread of infection to the cavernous sinus.

• Hydrocephalus.

• Intracranial, para pharyngeal, and prevertebral abscess.

• Death.

Conclusion

With enhanced medical and surgical techniques, the occurrence of Gradenigo syndrome is becoming rare now. The prognosis of the syndrome is good if diagnosed early before it spreads to the key structures. The discovery of antibiotics has made it possible to prevent the spread of infection to other parts. A regular follow-up with an otolaryngologist is essential.