320 THE EAR
Recently much work has been done on the theory that this condition may
be included among the auto-immune diseases.
PATHOLOGY. The fluid is always sterile on culture, and has a relatively
high protein content especially in serous fluid, while protein-bound carbo-
hydrates are frequently present in higher concentration in fluid of a high
viscosity. Cellular elements, macrophages, lymphocytes, polymorphs and
plasma cells are found in varying proportions, but eosinophils are seldom
identified. Culture for viruses has generally proved unrewarding. Biopsy of
the middle ear mucosa demonstrates an increase of mucus-secreting cells, a
decrease of serum-secreting cells and a degeneration of the ciliated epithelium.
SYMPTOMS. The prime, and often the only, symptom is deafness. This
may not be noted by the parents, but may be recognized by the teacher in
the nursery or primary school. It may only be discovered by the screening
of children by the school audiometric service. If deafness is suspected by
the parents it may be said to have dated from a specific upper respiratory
tract infection, with or without earache. All too often parents attribute lack
of hearing to inattention or preoccupation on the part of the child. Many
parents will comment on the fact that the child turns up the volume of the
television set. The ambient level of noise in many households is such that
voices are raised, and the deafness of the affected child goes unnoticed.
CLINICAL FEATURES. The onset is generally gradual, and in very young
children it may be unrecognized. In such children slow development of
speech or defects in speech may be the cause of referral to hospital, and all
such children should have an otological examination. Aspiration of middle
ear glue may be all that is required.
The condition occurs most frequently in the 4—7 years age group, and is
less common in older children. Examination of the ear may show the drum-
heads occluded by wax which is often crusted. When the membranes are
seen there is no single diagnostic feature. The drumhead may be indrawn,
sometimes slightly, sometimes acutely. On other occasions it may appear
full posteriorly or postero-inferiorly. A long-standing case or a recurrent
case may show retraction pockets either in the attic above the lateral process
of the malleus, or posterosuperiorly below the posterior horizontal fold,
In the latter instance there is a well-defined lower edge to the retraction,
and this edge is concave upwards.
Various colours of the membrane may be noted. In a few cases the drum-
head may appear nearly normal in colour but there are dilated surface
vessels along the handle of the malleus and as a palisade in the lowest part
of the membrane. A thin serous fluid may show as a yellow or amber-
coloured drumhead, and the handle of the malleus appears chalky-white
against the darker background. Most membranes are flushed rather than
congested, and dilated vessels are seen to radiate on the surface. Should the
middle ear fluid contain blood pigments the membrane will appear blue,
varying from a slate colour to inky blue.
A characteristic finding, which is not easy to elicit in children, is that
there is a loss of the normal drum movement when positive and negative
pressures are applied by the pneumatic (Siegle's) speculum.
The condition is occasionally met with in adults or in the elderly, usually
after a severe cold. It is more often unilateral. Otoscopy may show a
fluid level with a concave meniscus (see Plate X, 3), or air bubbles