Nonfundus Signs and Symptoms of IICP
Enlargement of the Blind Spot - Disc swelling for any reason causes perimetric enlargement of the blind spot. It is not likely to be seen before physical signs of disc swelling.
Transient Visual Obscurations - Bilateral transient loss of vision lasting 15 to 30 seconds is a positive symptom of IICP. Patients frequently blame it on something else and fail to report it. You must specifically ask about this symptom explaining the details of the symptom.
Pupillary Abnormalities - Pupil abnormalities are not usually part of papilledema and IICP.
However,supratentorial masses as they encroach on the tentorial notch can compress the third nerve and cause a large and poorly reactive pupil. Further pressure can compress the cerebral peduncle beneath it and cause contralateral hemiparesis. Occasionally the pressure is directed to the opposite side and the hemiparesis is ipsilateral to the pupil and is called a Kernahan Notch Syndrome. The basic clinical rule of thumb is to trust that the abnormal pupil is the side on which the lesion is located. This is particularly useful in deciding which side to drill a burr hole to relieve pressure from a subdural collection of blood.
Lateral Rectus Weakness - A lateral rectus palsy can be a result of IICP. However, if one is following IICP, such as occurs in pseudotumor cerebri, a horizontal phoria measurement at distance with a Maddox rod should be made at each visit in order to monitor a more subtle lateral rectus weakness. An increasing esophoria at distance is a sign of an impending 6th nerve palsy.
Headache - Headache is frequently associated with IICP. The headache is increased by maneuvers that increase intracranial pressure such as a Valsalva. That maneuver in contrast frequently helps vascular headaches and has no influence on tension headaches. Nausea and vomiting which are traditionally associated with IICP is infrequently seen with vascular headaches. Headache located behind the ear is suggestive of venous sinus thrombosis.
Venous Souffle' - This is soft sound heard by the patient when he is very quiet as is the case just before going off to sleep. It is a soft blowing sound. It is a subjective response in that it is heard only by the patient and can not be heard by the examiner. It is not always mentioned by the patient, in contrast to carotid cavernous fistula which is.
Thomas J. Walsh, M.D.