Otitic Hydrocephalus - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Otitic hydrocephalus is a condition in which increased intracranial pressure is observed. It occurs due to a complication of a middle ear infection called otitis media. Cerebrospinal fluid composition is not affected, but an elevated cerebrospinal fluid pressure is present intracranially. It most commonly occurs in children and young individuals. Uncommon in adults.

What Is Otitic Hydrocephalus?

Otitis hydrocephalus is a rare condition in which there is an intracranial pressure elevation due to cerebrospinal fluid. This condition is due to a complication of middle ear infections like otitis media. In this, cerebrospinal fluid (CSF) remains normal. This condition was first described by Symonds. This is considered a syndrome.

It is also known as pseudotumor cerebri. Its mechanism needs to be clearly known. It may be due to increased production of cerebrospinal fluid or reduced absorption of cerebrospinal fluid. There are no associated neurological findings with this condition except for intracranial pressure.

What Are the Causes of Otitic Hydrocephalus?

This is a rare complication of middle ear infections. This can be caused due to

• Acute otitis media.

• Chronic otitis media.

• Otologic surgery.

First, it was thought that this condition was caused due to otitis media and others. Later it was found that the actual cause of this condition is thrombosis of the transverse sinus (blood clot formation in the brain’s venous sinuses).

Otitis hydrocephalus may be a misnomer as later it was considered this condition might occur in the absence of otitis and also that individuals affected may not have dilated ventricles that indicate true hydrocephalus.

Many names were coined by many authors, like serous meningitis, pseudotumor cerebri, and benign intracranial hypertension.

The pathophysiology of this condition varied with time and different authors who conducted research.

• Earlier, Symonds thought that this condition was due to an infection of the lateral sinus extending into the confluence of the sinuses to involve the superior sagittal sinus (major dural sinus present in the brain, which receives venous drainage). When this superior sagittal sinus is infected, it prevents CSF absorption leading to a rise in intracranial pressure.

• In 1933, Weed and Flexner thought that the rise in intracranial pressure in this condition is due to the disruption of venous circulation.

• In 1969, Hosal thought that cause was a vasomotor reflex phenomenon that arose in the thrombosed epithelium of the vein rather than due to obstruction in the vein.

The most common bacterias involved are S. pneumoniae, S. pyogenes, and H. influenzae.

Hence the etiology is not known properly.

What Are the Symptoms of Otitis Hydrocephalus?

Though the cause is unknown, the symptoms are consistent. They are

• Increased intracranial pressure.

• Headache.

• Drowsiness.

• Vomiting.

• Blurred vision.

• Diplopia.

• Acute or chronic otitis media.

• Papilloedema and ipsilateral abducens nerve palsy.

• Optic atrophy may develop slowly.

• Fluctuation of CSF fluid pressure can be transmitted to the inner ear and may cause headache, and this may trigger migraine-associated vertigo (dizziness).

• The condition of otitis hydrocephalus is linked to lateral sinus thrombosis. Not all people who have lateral sinus thrombosis will have otitis hydrocephalus.

How to Diagnose Otitis Hydrocephalus?

The diagnosis of otitis hydrocephalus is an exclusion as a high degree of suspicion is required to relate the symptoms. Ear symptoms are not much evident as other symptoms like headache, blurred vision, etc, which are prominent.

1. Fundoscopic Examination: It is done to look for papilloedema as evidence of intracranial pressure. This examination is enough to diagnose this condition in the absence of ventricular dilation or meningitis.

2. Magnetic Resonance Imaging (MRI): This imaging test is done to rule out any space-occupying lesion in the sinus. It gives a superior image of the venous sinuses. It is a good tool to visualize the thrombi.

3. Computed Tomography (CT): This test is also done to view the sinuses.

4. Magnetic Resonance Venography: This is used to view the dural venous thrombosis. This test is not done to diagnose otitis hydrocephalus.

What Are the Treatments for Otitis Hydrocephalus?

Treating the condition is very important -

• To decrease intracranial pressure.

• To overcome any ear diseases present.

• To prevent serious complications like optic nerve atrophy.

If surgery is not indicated, then the condition should be treated with medications.

• Medications like Acetazolamide, corticosteroids, diuretics, and Mannitol are used to decrease intracranial pressure.

• Decompression of sigmoid sinus.

• Mastoidectomy is done to remove the infectious process (cholesteatoma) and address the thrombosis. While performing mastoidectomy, an incision is placed on the lateral sinus, the clot is removed, and local packing is given. It is important to remove all perisinus infections.

• Anticoagulants are used to be given before giving antibiotics for individuals with lateral sinus thrombosis. These are not in use nowadays as they may increase the risk of venous infarctions.

• For individuals affected with lateral sinus thrombosis who do not respond to initial surgery and antibiotics, internal jugular ligation is reserved.

• For some individuals, optic nerve decompression is necessary. Optic nerve sheath fenestration reduces the CSF pressure placed on the optic nerve. When the pressure decreases, the vision improves.

• Lumbar drainage of CSF can be performed serially or continuously by placing lumbar drainage.

• A shunt may be required if drainage has to be done for long periods of time.

• Repeated lumbar puncture or long-term thecoperitonial shunting may be necessary. Treatment should be continued for many weeks. Permanent vision loss is uncommon. If such complications occur, they cannot be repaired.

What Is the Differential Diagnosis of Otitis Hydrocephalus?

To rule out brain abscesses, other sources of elevated intracranial pressure and computed tomography are required.

Conclusion

The ear is an important organ of the body. It helps in the hearing process. Any slight changes in the ear lead to discomfort. This affects the quality of life of an individual. Otitis hydrocephalus is a complication of a middle ear infection. This creates elevated intracranial pressure. This condition, if not treated, leads to serious complications. As a result, it is critical to understand the ailment, including its causes, symptoms, diagnosis, and treatment. Understanding allows individuals to seek medical guidance as soon as possible. Early detection aids in the delivery of successful treatment. This, in turn, contributes to a high quality of life.