Occasionally, an abscess forms in the lymph nodes behind a child's pharynx which bulges forwards. Sometimes an abscess is the result of infection round an impacted fish bone. If the swelling is large enough, he may asphyxiate. If it bursts, he may get an aspiration pneumonia. The major differential diagnosis is a chronic tuberculous retropharyngeal abscess.
RETROPHARYNGEAL ABSCESSES For the general method, see Section 5.2. If the patient is dehydrated, give him intravenous fluids.
ACUTE ABSCESS IN A CHILD. The great danger of a general anaesthetic is that the patient will inhale pus. Ketamine is relatively safe because his cough reflex is less suppressed. Give it intravenously, give only just enough, and keep his head down.
Have a tracheostomy set (52.2) and suction ready. Lie him on his back with his head over the end of the table, so that his pharynx is as nearly upside down as possible.
If his abscess is pointing, you may be able to open it with sinus forceps alone. If you can get a really good view, you may be able to aspirate it with a needle. If this is impractical, open his abscess with a guarded knife (5-6). Put your index finger into his mouth, and slide the knife along it. Drain it by Hilton's method (5-3), as for a peritonsillar abscess.
CAUTION ! Don't let him inhale pus[md]suck immediately you incise.
If severe bleeding follows, and you cannot control it, apply local pressure for 15 minutes. If that fails (rare), be prepared to tie his external carotid artery (3.3).
ACUTE ABSCESS IN AN ADULT. Anaesthetize the mucosa over the abscess with 4% lignocaine, preferably as an aerosol, and incise it with his head down and on one side, as in a child.
TUBERCULOUS RETROPHARYNGEAL ABSCESSES (rare) are usually subacute and follow infection of the body of a vertebra. Refer him if you can. Only consider drainage if obstruction to his airway is a real danger. Drain his abscess through an external incision in front of his sternomastoid down to his prevertebral fascia. Displace his thyroid gland and trachea anteriorly.