Chronic retropharyngeal abscess

Retropharyngeal abscess is a collection of pus between the posterior pharyngeal wall and the fascia and muscles covering the cervical vertebrae. It occurs in two forms - 1. The acute primary retropharyngeal abscess which is common in infants, and 2. Chronic retropharyngeal abscess which is common in adults. These two types of abscesses differ in their etiology and management.

Chronic retropharyngeal abscess commonly known to occur in adults. This is usually caused by tuberculosis. The tuberculous foci occur in the bodies of the cervical vertebrae( Pott's disease) which later spread into the retropharyngeal space. Primary syphilis of the mouth and pharynx may also cause retrophrayngeal abscess. This abscess usually is present in midline and is free to spread to either side also. Rarely infections can spread from tonsils to involve this space.

Symptoms: These patients have excruciating pain while swallowing (odynophagia). Young infants with retrophryngeal abscess will refuse feed, may have extensive drooling. In adults the head may be held straight. Torticollis is also common in these patients. These patients may have difficulty in breathing (stridor), in which case tracheostomy must be considered to secure the airway in the first place. Constitutional symptoms like fever / toxicity is very common in acute retropharyngeal abscess.

Investigations:

Complete blood count show leucocytosis. Blood cultures can also be performed to ascertain the appropriate antibiotics to be used.

C reactive proteins are also found to increased in these patients

Xray soft tissue neck - A.P. and lateral views.

These pictures show prevertebral soft tissue widening. This can be ascertained by estimating the size of the prevertebral soft tissue which is normally half the size of the body of the corresponding vertebra. If the widening is more than half the body size of the corresponding vertebra then retropharyngeal abscess must be considered. The cervical spine are straightend with loss of the normal lordosis (Ram Rod spine). Above the prevertebral shadow air shadow is seen in almost all cases of retropharyngeal abscesses. This gas shadow is caused by entrapped air which occur during breathing. Some bacteria esp. Clostridium are known to form gases which may be entrapped in the prevertebral space.

If tuberculosis is considered to be the cause of chronic retropharyngeal abscess then surgery is contraindicated. Anti tuberculous therapy is initiated.

Patients with non tuberculous chronic retropharyngeal abscess need to undergo incision and drainage under local anesthesia. Local anesthesia is preferred in order to prevent aspiration.