THE AURAL COMPLICATIONS 
OF INFLUENZA. 
BY 
EDWARD B. DENCH, M. D. 
Professor of Otology, Bellevue Hospital Medical College; 
Consulting Otologist to St. Luke's Hospital; Attending 
Aural Surgeon, N. Y. Eye and Ear Infirmary ; 
Fellow of the American Otological 
Society; of the N. Y. Otolog- 
ical Society, etc. 
REPRINTED FROM 
©ransattions of gark ^cabling of gjtbicine 
for 1895. THE AURAL COMPLICATIONS .OF 
INFLUENZA. 
BY 
EDWARD B. DENCH, M. D. 
PROFESSOR OF OTOLOGY, BELLEVUE HOSPITAL MEDICAL COLLEGE ; CONSULTING 
OTOLOGIST TO ST. LUKE'S HOSPITAL; ATTENDING AURAL SURGEON, 
N. Y. EYE AND EAR INFIRMARY; FELLOW OF THE 
AMERICAN OTOLOGICAL SOCIETY J OF 
THE N. Y. OTOLOGICAL 
SOCIETY, ETC. 
\Reprinted from Transactions of the New York Academy of Medicine. 
CONCORD, N. H.: 
THE RUMFORb PRESS. 
1898. THE AURAL COMPLICATIONS OF INFLUENZA. 
In considering this subject we have first to remember 
that epidemic influenza belongs to the class of acute infec- 
tious diseases. The constitutional poison effects certain 
general changes common to all acute infectious diseases, 
and therefore the influence of this malady upon any par- 
ticular organ of the body resembles that of any other acute 
systemic infection. According as the toxic principles 
expend themselves either upon the upper air passages or 
upon the nerve centers, the aural complications usually 
manifest themselves as affections of the conducting 
mechanism or of the perceptive tract. It is still a mooted 
question whether the effect produced upon this organ of 
special sense is due to the action of the specific germ of 
the disease, or whether the development of certain toxines 
in the blood renders the tissues more vulnerable to the 
action of certain micro-organisms found in similar local 
conditions, not depending upon influenza. When the ner- 
vous system is principally involved the action upon the 
organ of hearing may be indirect; some disturbance of the 
vaso-motor center so affecting the circulation in either the 
external or middle ear, or in the labyrinth, as to impair or 
pervert audition without causing an inflammation. 
For convenience of classification we may consider the 
effects of this disease upon the external auditory meatus, 
upon the middle ear and the Eustachian tube, and upon 
the labyrinth and trunk of the auditory nerve. Why in 
certain cases aural complications play so prominent a part, 
while in others the ear remains unaffected, undoubtedly 
depends upon some pre-existing local condition. The same 4 
Dench : The Aural Complications op Influenza. 
cause is often operative in determining the particular part 
of the auditory apparatus affected. 
It is probable that an external otitis either of the circum- 
scribed or diffuse variety directly complicating epidemic 
influenza, is rather rare. Such complications can usually 
be explained upon the theory that the intense congestion 
of the vessels of the head which the disease causes, ren- 
ders the tissues of the canal especially susceptible to in- 
fection. 
In one instance which came under my own observation, 
there was an extensive growth of aspergillus in either 
external auditory meatus, following a severe attack of 
influenza. No doubt the spores had been present in the 
canal for an indefinite period, but the intense local conges- 
tion which the constitutional disease caused constituted a 
condition that accelerated their growth sufficiently to pro- 
duce severe symptoms. 
The development of vesicles upon the walls of the 
meatus and upon the surface of the drum membrane has 
also been observed in cases of this constitutional malady 
and may, I think, be considered as trophoneurotic in origin 
and of the sdme nature as herpes. These vesicles are 
sometimes filled with clear serum, while in other instances 
they are filled with blood. 
When we come to consider the middle ear and the 
Eustachian tube the importance of a previous pathological 
condition of the upper air-passages must be borne in mind. 
Adenoid growths in the nasopharynx, nasal obstruction, 
enlarged faucial tonsils, etc., are all operative in causing 
involvement of the middle ear. The complications vary 
in severity from a simple closure of the Eustachian tube 
on the one hand, to a severe suppurative otitis media with 
mastoid involvement upon the other. Why, in one in- 
stance, the patient should escape with a simple tubal 
congestion, and in another case should suffer from acute 
suppuration, is still a matter of conjecture. The most Dench : The Aural Complications of Influenza. 
5 
plausible explanation is that the intensity of the local 
complication depends upon the degree of systemic infec- 
tion. It is also probable that some pre-existing local con- 
dition may have rendered the parts particularly suscepti- 
ble to infection. It is doubtful whether the disturbance is 
ever caused by the local action of the specific microbe of 
influenza. Thus in a simple tubal catarrh we have a 
relaxation of the vessels of the Eustachian tube and an 
intense congestion and oedema of its lining membrane 
completely occluding the canal. The effect upon the mid- 
dle ear depends entirely upon the reduction of atmospheric 
pressure in the tympanum. This constitutes the mild type 
of middle-ear complication in influenza. Carried one step 
further, the vessels within the middle ear dilate and there 
is transudation of serum into the tympanic cavity. This 
fluid forms an exceedingly good culture medium for the 
development of bacteria which may find their way into the 
cavity through the tube. In the more virulent cases the 
connective tissue structures lying in the upper part of the 
tympanic cavity become susceptible to the action of pyo- 
genic bacteria, and then we have a severe inflammation of 
this connective tissue, or an acute purulent otitis. The 
middle ear then will be the site of a simple transudation, a 
mild catarrhal inflammation, or a purulent inflammation 
according as the power of resistance of the tissues is 
diminished by the action of the poison circulating in the 
blood. 
The aural complications observed during the various 
epidemics seem rather to bear out this view. In the first 
epidemic in this country, the aural complications were far 
more grave than in the epidemics of the last two years. 
The involvement of the mastoid process was exceedingly 
common and usually so rapid in progress as to necessitate 
operative interference. During the past two years simple 
tubal congestion or a congestion of the tube and middle 
ear with an effusion of serum into the tympanic cavity, 6 
Dench : The Aural Complications of Influenza. 
has been more common than an acute purulent inflamma- 
tion. 
The symptoms to which these various conditions give rise 
are so well known as to scarcely demand remark here. It 
is well to remember, however, certain appearances which 
enable us to decide between an acute purulent process and 
simple catarrhal inflammation or tubal and tubo-tym- 
panic congestion. An acute purulent inflammation with- 
in the tympanum must of necessity involve the connec- 
tive tissue structures lying within the tympanic vault, 
hence otoscopic examination reveals in the early stages an 
intense congestion of that portion of the membrane lying 
above the short process of the malleus, while the remain- 
der of the membrane may be perfectly normal in color. 
This may be the only deviation from the normal standard 
and yet the patient may complain of intense pain in the 
ear. Viewed a few hours later we find the upper portion 
of the drum membrane bulging into the canal, frequently 
to such an extent as to hide the short process, while the 
superior wall of the meatus seems to be continuous with 
this red, bulging portion. The tumefaction may be so 
great as to partially hide the part of the membrane 
below the processus brevis, and the inflammation may 
advance so rapidly as to cause but little deviation from the 
normal standard of color in the inferior portion of the visi- 
ble drum membrane. An inflammation here is exceedingly 
prone to be followed by mastoid inflammation unless dealt 
with promptly. It is always wise to incise this tume- 
fied tissue immediately, the knife being inserted close 
behind the short process of the malleus, carried backward 
to the periphery of the drum membrane, and then outward 
upon the canal wall. The object of this incision is to de- 
plete the tissues of the tympanic vault and thus to abort 
the inflammation. If instituted early this plan seldom fails 
to prevent extension to the mastoid process. Even after 
disintegration has taken place within the tympanum, and Dench : The Atiral Complications of Influenza. 
7 
pus is evacuated upon incision, the free use of the knife as 
described not infrequently prevents extension to the mas- 
toid process. 
The picture presented by a simple tubal catarrh, tubo- 
tympanic congestion, or an acute catarrhal inflammation is 
very different. In tubal catarrh the changes seen upon 
speculum examination depend simply upon the rarefac- 
tion of the air within the tympanum. The drum mem- 
brane is drawn inward, the short process of the malleus is 
prominent, the long process fore-shortened, and the trans- 
verse diameter of the fundus of the canal is apparently 
increased, owing to the displacement inward of the poste- 
rior segment of the membrane. There is no congestion 
of the membrane and no increased vascularity of the canal, 
the tissues above the short process of the malleus appear- 
ing perfectly normal. 
Where both the tube and middle ear are congested we 
have, in addition to a displacement of the drum mem- 
brane inward, a turgescence of this structure itself lim- 
ited to its periphery and to the manubrial plexus. If there 
has been a transudation of serum into the cavity we may 
recognize either the fluid line if the membrane is suffi- 
ciently thin, or air bubbles may be seen in the fluid appear- 
ing as bright points which change their position upon forc- 
ing air into the middle ear. A sign of practical importance 
is that the region of increased vascularity is confined to 
the region of the larger blood vessels,-in other words, 
it is limited to the periphery of the membrane and to the 
manubrial plexus. There is no injection of the membrane 
itself, but simply a dilatation of the normal venous chan- 
nels. 
In an acute catarrhal inflammation, the lower portion of 
the tympanic cavity alone is involved; the drum mem- 
brane is uniformly reddened, and presents an appearance 
very different from that seen when the process is of an 
acute purulent character. In this last condition we have 8 
Dench : The Ariral Complications of Influenza. 
already stated, that the parts first affected were situated 
above the short process of the malleus. In an acute 
catarrhal inflammation the entire tympanic membrane, 
particularly the membrana vibrans or that part lying 
below the short process of the malleus, at first appears 
pinkish, and then of a deeper red color. The membrane 
bulges into the canal as the fluid accumulates behind it, 
and this fluid is sero-mucous in character, and not puru- 
lent. It is seldom that the increased vascularity reaches 
such a stage as to completely obscure the short process 
of the malleus, and often the entire outline of the manubrium 
can be made out. 
Here also an early and free incision is demanded to pre- 
vent a subsequent extension to the cellular tissue in the 
tympanic vault. When the effusion is not excessive it may 
be absorbed, the process being aided by inflation. If there 
is a large quantity of fluid it must be evacuated by a free 
incision. Paracentesis or simple puncture of the mem- 
brane is not sufficient to evacuate the fluid in these cases. 
The incision should lie in the posterior segment, should be 
free, and should follow the periphery of the membrane, 
extending from the lower and posterior portion of the mem- 
brane upward to the posterior fold. This not only evac- 
uates the inflammatory products, but also thoroughly de- 
pletes the tissues and favors a rapid return to the normal 
condition. It is well in making this incision to carry the 
knife inward until the internal tympanic wall is encount- 
ered, and to divide the mucous membrane covering this, 
as well as the drum membrane, in order to more completely 
empty the engorged vessels. 
Where we have to deal with tubal obstruction, or with 
a tubo-tympanic congestion, catheterization is usually suf- 
ficient to relieve the condition; if, however, there has been 
an extensive effusion it may be necessary to evacuate this 
by incision as in the cases of acute catarrhal inflammation. 
To recapitulate, the gravity of the middle-ear complication Dench : The Aural Complications of Influenza. 
9 
depends upon the portion of the tympanic cavity involved, 
and this in turn is determined by the appearance of the 
parts upon otoscopic examination. Those cases in which 
the tympanic vault is affected are of a grave nature, rapid 
in progress, and frequently extend to the mastoid; they 
are characterized by redness and bulging of the mem- 
brana tympani above the short process of the malleus, 
the superior wall of the canal appearing to sink down- 
ward so as to partially hide the drum membrane, and thus 
reduce the vertical diameter of the fundus of the canal. 
Those cases involving simply the Eustachian tube, or the 
tube and lower portion of the middle-ear cavity, are of a 
less serious nature and are not as a rule followed by mast- 
oid inflammation. Here the speculum shows no diminution 
in the vertical diameter of the drum membrane and that 
portion of the membrane above the short process of the 
malleus is not involved, the lower portion of the tympanic 
cavity being alone affected. 
So far we have considered those cases seen in the early 
stages and before perforation of the drum membrane has 
taken place. When the drum membrane has ruptured 
spontaneously, the perforation is usually small and must 
be enlarged in order to effect free drainage. An investi- 
gation of the discharge from the middle ear in these cases 
has shown the presence of the ordinary bacteria of suppu- 
ration, and according to Scheibe1 a bacillus of a particular 
form which is found only in cases following influenza, and 
which seems to be identical with the influenza microbe ob- 
served by Pfeiffer, Kitasato, and Canon. As the flinical 
history of these cases differs only in degree from that of an 
acute otitis media arising from other causes, it seems more 
probable that this particular bacillus is not the cause of 
the inflammation, but that by its action the tissues are 
rendered more susceptible to the ordinary bacilli of sup- 
puration. 
1Miinchen. med. Wochenschrift, 1892, No. 14. 10 
Dench : The Aural Complications of Influenza. 
The treatment of the discharge from the ear which 
appears either after spontaneous rupture, or after incision, 
is a matter of importance, to prevent either mastoid inflam- 
mation, or the infection of the external auditory meatus. 
The parts must be kept thoroughly cleansed, and this 
can best be done by frequent irrigation. Boiled water, or 
a mild antiseptic solution, is to be employed, the ear being 
irrigated twice or more times daily according to the amount 
of discharge. Where early incision has been employed 
the discharge seldom lasts more than a few days. Where 
spontaneous rupture has taken place the discharge disap- 
pears only after a considerable period and is much more 
profuse. In the catarrhal cases cleanliness is of the 
utmost importance in order to prevent infection of the 
discharge in the canal and the subsequent development 
of a purulent inflammation. It is also necessary in cases 
where an incision is to be made to thoroughly sterilize the 
canal before operating, in order to prevent infection. This 
is best done by wiping out the meatus with an alcoholic 
solution of the bicholoride of mercury (1-3000). All 
instruments should be sterilized by boiling. Too much 
cannot be said in favor of an early free incision in all 
cases when the tympanic vault is involved, and in cases 
of acute catarrhal otitis which threaten to perforate spon- 
taneously. Evacuation of the fluid by surgical means is 
always to be preferred to evacuation by spontaneous per- 
foration. 
Where the mastoid is involved, the early application of 
cold by means of the aural icebag, or the Leiter coil, may 
abort the inflammation. In regard to the particular part of 
the mastoid affected in these cases Politzer1 has observed 
that the superficial cells are more frequently involved, while 
the antrum escapes, being shut off from the purulent focus 
by the swelling of the mucous membrane; he therefore 
deems it unnecessary in operating upon such cases to 
1Archiv. fur Ohrenheilkunde, Vol. XXX, p. 252. Dench : The Aural Complications of Influenza. 
11 
enter the antrum and limits his operative interference to 
the superficial cells. In cases which have come under my 
own observation where the mastoid has been involved, the 
process has not limited itself to the superficial cells and I 
have found it necessary to perform the ordinary radical 
operation. There is no harm in opening the antrum and 
if it is not done a purulent focus may be overlooked. From 
the extreme rapidity with which the mastoid inflammation 
progresses early operation in these cases is to be advised. 
If cold is used, in the hope of aborting the inflammation, 
it should not be continued longer than forty-eight hours. 
It is true that the tenderness may disappear temporarily 
after the local application of cold for a longer period than 
that mentioned, but it has always been my experience, that 
operative interference was required at a later period, if 
cold applications had failed to obliterate local tenderness 
in forty-eight hours. The prolonged application of the 
ice-coil simply holds the mastoid inflammation in check, 
but does not cause it to disappear. 
In cases demanding operation, either on account of the 
attempt to abort the mastoid inflammation having been 
unsuccessful, or because the patient was seen after the 
osseous tissue was so involved as to render all other treat- 
ment useless, the writer has been impressed with the 
amount of destruction which had taken place even in 
acute cases. Often the entire mastoid has been found 
to be filled with granulation tissue, although the dis- 
ease was of but short duration. For this reason therefore 
a complete and thorough operation is always advisable, 
the entire mastoid process being converted into one large 
cavity by the free use of the curette and chisel, and free 
communication being established between this cavity and 
the middle ear in all cases. 
The involvement of the -perceptive apparatus as the 
result of epidemic influenza is much less common than 
involvement of the middle ear. It is sometimes impossi- 12 
Dench: The Aural Complications of Influenza. 
ble to determine whether the lesion is located in the nerve- 
trunk or in the labyrinth. A diagnosis of the involvement 
of the perceptive tract is made chiefly by exclusion, the 
cases not presenting upon functional examination the char- 
acteristic evidences of an affection of the conducting mech- 
anism. Functional examination where the middle ear is 
involved, shows an increase in bone conduction, an eleva- 
tion of the lower tone limit, that is, an impaired perception 
for tuning-forks of low pitch, while the perception for 
the highest sounds of the musical register is unimpaired. 
We occasionally find in cases where the hearing has 
become impaired after an attack of influenza that these 
symptoms are wanting, and that there is no evidence of 
any inflammation present or previous, in the Eustachian 
tube, or middle ear, to explain the condition. We find 
that the lowest notes of the musical scale are heard 
perfectly, that bone conduction is diminished, and that the 
upper notes are usually perceived poorly, although the 
upper-tone limit may be normal. Here we are compelled 
to believe that the labyrinth, or in some cases the auditory 
nerve-trunk, is the part affected. The changes which 
have taken place can only be surmised, but when we 
remember the circulatory disturbance which epidemic 
influenza causes it will not seem strange that the laby- 
rinthine circulation should suffer. It seems probable that 
in many cases these circulatory disturbances may be 
angioneurotic in character. 
The result of treatment in some of these cases would indi- 
cate that there had been an effusion into the bony labyrinth, 
increasing the labyrinthine pressure, and thus impairing 
audition. In one instance-that of a young man aged 
fifteen years-there was tinnitus and marked impairment 
of hearing. The audition was greatly interfered with by 
loud noises, the patient hearing better in a quiet place 
than in a noise. Examination showed a great diminution 
in bone conduction, while the low notes of the musical Dench : The Aural Complications of Influenza. 
13 
scale were heard perfectly. Inspection and auscultation 
gave negative results. Under the administration of pilo- 
carpine, and later of strychnia, all these symptoms disap- 
peared completely and the hearing became normal. In 
some of these cases the presence of vertigo aids us in the 
diagnosis, while in others we must depend entirely upon 
the functional examination and the absence of any physi- 
cal evidence of inflammation of the middle ear, in order to 
decide upon the location of the lesion. 
There is one condition which deserves attention, and that 
is the ease with which the auditory apparatus is fatigued 
in certain cases of aural involvement after influenza. The 
hearing may be surprisingly good at the beginning of the 
examination, but as this is prolonged the power of audi- 
tion gradually diminishes. These patients also complain 
that the effort to hear for any length of time causes great 
fatigue. This auditory fatigue not infrequently compli- 
cates an affection of the middle ear, and unless recog- 
nized, efforts at treatment are disappointing; the middle 
ear condition may yield entirely to treatment, and yet the 
power of audition will remain far below the normal stand- 
ard. The use of strychnia in large doses seems to be the 
most successful means of overcoming this phenomenon. 
It is scarcely probable that this symptom depends upon any 
labyrinthine disturbance, and it is more than likely that it 
is due to certain changes in the auditory nerve-trunk. 
Gradnigo1 reports an instance in which in addition to the 
fact that the auditory nerve became easily fatigued, there 
was also faulty perception for the middle notes of the 
musical register, a condition which he considers indicative 
of involvement of the nerve-trunk. 
1Afchiv. fiir Ohrenheilkunde, Vol. XXVI, p. 141