Tympanocentesis, first described in 1768, is a diagnostic and therapeutic procedure in which a needle is inserted through the tympanic membrane to aspirate fluid from the middle ear (Figure 199-1). The procedure is considered diagnostic when the material obtained is sent for laboratory and/or microbiological analysis. It is considered therapeutic in most instances because it relieves pressure, reducing pain, and often shortens the course of acute otitis media (AOM).
Tympanocentesis of the right ear. The patient is lying supine with their head directed to the left. A. An ear speculum is inserted into the external auditory canal. A needle is inserted through the posterior inferior quadrant of the tympanic membrane to aspirate middle ear fluid. B. Magnified view of the tympanic membrane.
The procedure is quick, simple, and not as frequently performed as it should be. General practitioners and Pediatricians would frequently perform the procedure for the relief of pain in the preantibiotic era. Tympanocentesis is making a resurgence. It should be considered when a patient presents to the Emergency Department seeking treatment for a painful AOM.1 The American Academy of Family Physicians, American Academy of Pediatrics, and the Centers for Disease Control and Prevention all include tympanocentesis in their practice guidelines for AOM. Many authors are calling for culture-directed antibiotic therapy for otitis media to reduce the need for broad-spectrum antibiotics and prevent the emergence of multiresistant organisms.2-7
ANATOMY AND PATHOPHYSIOLOGY
The ear is divided into the external, middle, and inner parts. The external ear is comprised of the auricle, the external auditory canal, and the external auditory meatus. The middle ear contains an air space and mastoid cells ventilated by the eustachian tube, the tympanic membrane, and the three ossicles. The inner ear is comprised of the cochlea, semicircular canals, fluids, and cranial verve VIII. The facial nerve courses through the middle ear space and mastoid process. It can be affected by a severe infection in these areas. Facial asymmetry during an acute ear infection is an indication of an unusually severe infection.
Inspection of the tympanic membrane will usually show it to be bulging during an acute infection with loss of mobility on pneumatic otoscopy. Conditions that are more chronic may show color changes of the tympanic membrane. There may be associated scarring and distortion.
Tympanocentesis is performed to obtain fluid for microbiological culture and antibiotic sensitivity testing to determine the infectious cause of a middle ear effusion.1 Tympanocentesis is warranted for patients with AOM that is severe or unresponsive to conventional antimicrobial therapy for 48 to 72 hours or in a child less than 8 weeks of age to rule out gram-negative organisms. ...