Other signs with subacutely evolving masses in the posterior fossa include pain in the neck, stiff neck, head tilt, and paresthesias in the shoulders, dysphagia, and loss of tendon reflexes in the arms. Head tilt, stiff neck, arching of the neck, and paresthesias over the shoulders are attributable to the herniation of the cerebellar tonsils into the foramen magnum, and tonic extensor spasms of the limbs and body (so-called cerebellar fits) and coma are caused by the compressive effects of the cerebellar mass on medullary structures or of hydrocephalus on upper brainstem structures. In any case, respiratory arrest is the feared and often fatal effect of medullary compression by a “cerebellar pressure cone.” It may occur suddenly, without the aforementioned additional signs. With cerebellar mass lesions there may also be upward herniation of the cerebellum through the incisura of the tentorium. The clinical effects have not been clearly determined, but Cuneo and colleagues have attributed decerebrate posturing and pupillary changes—initially both pupils are miotic but still reactive, progressing to anisocoria and enlargement—to this type of brain displacement.
It should be stated that, early in their evolution, tumors of the brain may exist with hardly any symptoms. A slight bewilderment, slowness in comprehension, or loss of capacity for sustained mental activity may be the only deviations from normal, and signs of focal cerebral disease are wholly lacking. On the other hand, there is in many patients with brain tumor an early indication of cerebral disease in the form of a progressive hemiparesis, a seizure, aphasia, or behavioral change such as disinhibition, occurring in a previously well person. In a third group, the existence of a brain tumor is apparent because of the presence of the signs of increased intracranial pressure such as relentless and morning headache, vomiting, diplopia, or intermittent visual blurring. In yet another group, the symptoms are so characteristic as to make it likely that not only is there an intracranial neoplasm, but that it is located in a particular region. These localized masses create certain syndromes seldom caused by other disorders.
In the further exposition of this subject, intracranial tumors are considered in relation to these common modes of clinical presentation: 1. Patients who present with focal cerebral signs and general impairment of cerebral function, headaches, or seizures 2. Patients who present with evidence of increased intracranial pressure 3. Patients who present with specific intracranial tumor syndromes
Patients Presenting with Generalized and Focal Impairment of Cerebral Function, Headaches, or Seizures
Altered mental function, headache, dizziness, and seizures are the usual manifestations in this group of patients. Until the advent of modern imaging procedures, these were the patients who presented the greatest difficulty in diagnosis and about whom decisions were often made with a great degree of uncertainty. Their initial symptoms are vague, and not until some time has elapsed will signs of focal brain disease appear; when they do, they are not always of accurate localizing value.
A lack of persistent application to everyday tasks, undue irritability, emotional lability, mental inertia, faulty insight, forgetfulness, reduced range of mental activity (judged by inquiring about the patient’s introspections and manifested in his conversation), indifference to common social practices, lack of initiative and spontaneity—all of which may be misattributed to anxiety or depression—make up the cognitive and behavioral abnormalities seen in this clinical circumstance. Inordinate drowsiness, sleepiness, or apathy may be prominent. We have sought a convenient term for this complex of symptoms, which is perhaps the most common type of mental disturbance encountered with neurologic disease, but none seems entirely appropriate. There is both a reduction in the amount of thought and action and a slowing of reaction time. MacCabe referred to this condition as “mental asthenia,” which has the merit of distinguishing it from depression.