ACUTE OUTIS MEDIA 313
grey tinge above the line. Bubbles may also be visible through the drum-
head, produced by the pressure of air in the fluid and may be seen immedi-
ately after inflation of the middle ear. Catheterization produces differing
sounds on auscultation, being unduly loud in some cases and in others
producing an interrupted gurgling sound. If catheterization results in com-
plete diffusion of fluid the membrane assumes a more normal colour, but
in the presence of a thickened drumhead these changes may not be seen.
Ejection of the condition may also be difficult when the tympanum is
full of fluid. Then the membrane may have a darker colour than normal or
a distinctly yellow tinge with a glistening appearance. In some cases the
colour is bluish owing to the presence of blood in the effusion. The handle
of the malleus is often sharply defined.
In cases where the drumhead has a full or slightly bulging appearance
with dilatation of the vessels radiating from the malleus and showing
as red wavy lines on its surface (see Plate X, 4), an intermediate
stage between acute non-purulent and acute purulent otitis media has
DIAGNOSIS. The diagnosis can generally be made on the otoscopic appear-
ances particularly when a hairline or bubbles of air can be seen in the
tympanum. Deafness _of conductive type, shown by tuning fork tests and
confirmed by audiometry, is present. The pneumatic speculum used to
determine mobility of the drumhead may also demonstrate movement of
the hairline and air bubbles when they are present. In uncomplicated cases
successful inflation disperses fluid, equalizes pressure within the tympanum
to atmospheric pressure and restores hearing.
PROGNOSIS. In recent cases and in those due to obstructive causes such
as adenoids the prognosis is good provided that the causal condition is
adequately treated. Recurrences lead to structural changes in the middle ear
with a less favourable prognosis in regard to hearing.
TREATMENT. Dramagejjf fluid from the middle ear firstly by the natural
route., the Eustachian tube, may be assisted by the use of decongestant
nasal drops such as ephedrine hydrochloride 1 per cent in normal saline, by
steam inhalations containing menthol and by the administration of an ant i-
Mstarnine^preparation especially where an allergic factor is present. During
inhalations Valsalva's auto-inflation may be performed but successful infla-
tion may require politzerization or Eustachian catheterization carried out
daily. Failure of these measures with persisting deafness requires surgical
treatment, which should result in the immediate return of normal hearing.
Myringotomy is preferred to needle aspiration because of the latter's
frequent failure. The procedure is usually performed under general anaes-
thesia employing the operating microscope. A small stab incision in the
antero-inferior quadrant of the membrane permits the entry of air into the
middle ear and allows aspiration of the effusion. The myringotomy incision
tends to heal rapidly so that an effort should be made to obtain total aspira-
tion of fluid. In cases of persistent or recurring effusion myringotomy
requires to be repeated and a small plastic tube, a grommet, is inserted.
This provides further drainage and aeration of the middle ear. In most
cases the grommet is self-extruded in a few weeks or months. If not, it may
be removed either as an outpatient in adults or under anaesthesia in