Subdural empyema and herpes zoster syndrome (Hunt syndrome)

[tirath]

subdural empyema and herpes zoster syndrome (Hunt syndrome) complicating routine removal of third molars. Subdural empyema is an extremely rare but life-threatening complication of dental sepsis arising spontaneously or after dental surgery. The clinician should be familiar with its presentation and have a high index of suspicion, because late recognition and delay in its treatment can increase the associated morbidity and mortality. Surgical procedures and in particular maxillofacial surgery have also been known to trigger varicella zoster reactivation resulting in Hunt syndrome. Some patients develop the characteristic rash several days after the onset of facial weakness, so that Hunt syndrome may initially be misdiagnosed as Bell’s palsy.

        

[sushantpatel_doc]

Ramsay Hunt syndrome (RHS) type 2 also known as herpes zoster oticus is a disorder that is caused by the reactivation of pre-existing herpes zoster virus in a nerve cell bundle in the head (the geniculate ganglion). The neurons in this ganglion are responsible for the movements of facial muscles, the touch sensation of a part of ear and ear canal, the taste function of the frontal two-thirds of the tongue, and the moisturization of the eyes and the mouth. The syndrome specifically refers to the combination of this entity with weakness of the muscles activated by the facial nerve. In isolation the latter entity would be called Bell’s Palsy.

Symptoms and signs
The symptoms and signs include acute facial nerve paralysis, pain in the ear, taste loss in the front two-thirds of the tongue, dry mouth and eyes, and eruption of a erythematous vesicular rash in the ear canal, the tongue, and/or hard palate.

Since the vestibulocochlear nerve is in proximity to the geniculate ganglion, it may also be affected, and patients may also suffer from tinnitus, hearing loss, and vertigo.

Pathophysiology
RHS type 2 is essentially shingles of the geniculate ganglion. Briefly, the herpes zoster virus lies dormant in various nerve cells in the body, where it is kept in check by the patient’s immune system. Given the opportunity, for example during an illness that suppresses the immune system, the virus is reactivated and travels to the end of the nerve cell, where it causes the symptoms described above.

Like shingles, however, lack of lesions does not definitely exclude the existence of a herpes infection. The virus can be detected, even before the eruption of vesicles, from the skin of the ear.

Prognosis
The largest study on the treatment of RHS type 2 has shown that complete recovery can be achieved in 75% of patients if treatment with prednisone and acyclovir is started within the first 3 days of onset of facial paralysis. Chances of complete recovery decrease as treatment is delayed. Studies have shown that half of all patients whose treatment was delayed had complete loss of response to facial nerve stimulation.

Treatment apparently has no effect on the recovery of hearing loss.

Diazepam is sometimes used to treat the vertigo.

        

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