Nystagmus, or small consensual oscillations of the eyeballs, very often indicates the presence of cerebral disease. It is common in the second and third stages of tubercular meningitis, and is then accompanied by severe and obvious symptoms of intra-cranial mischief. It is not un frequently seen in chronic hydrocephalus and even in simple edema of the brain, and is sometimes present as a consequence of cerebral atrophy. In cases of tumour of the brain nystagmus often precedes paralysis of the ocular muscles as an early symptom of a growth within the skull. Nys tagmus is not, however, always a consequence of cerebral mischief. If it occurs in an infant in whom no other sign of nervous disturbance has been noticed it should suggest a congenital cataract ; for this lesion if left untreated is apt to induce oscillatory movements of the eyeball from alter nate contractions of the recti and oblique muscles of the eye. Even in older children the symptom may be due to a congenital cataract which has been overlooked. In rare cases nystagmus is the consequence of a local chorea.
The condition of the pupils should be always noted. During sleep in a healthy child the pupils are contracted but they dilate when the child wakes up. They are contracted in the early stage of meningitis, either the simple or tubercular form, and are also small if opium has been ad ministered in too large quantities. In the later stage of meningitis and in many forms of cerebral disease the pupils are large and equal. If they are sluggish and contract imperfectly or not at all under the influence of light, the sign is a very grave one. If they are unequal on the two sides, the eyes themselves being perfectly free from disease, we can have little hope of the patient's recovery.
Impairment or loss of sight is another symptom of importance. In tumour of the brain it occurs early, and if combined with headache and vomiting is very characteristic of a cerebral growth. It is often observed in meningitis and in thrombosis of the cerebral sinuses. Li these cases optic neuritis may. perhaps be discovered by the ophthalmoscope.
Delirium in the young baby is indicated by sudden screams, staring of the eyes, and a frightened look. In the older child by restlessness and random talking, as it is in the adult. The symptom is comparatively rarely the consequence of cerebral disease, although it may occur in cases of tubercular meningitis. As a rule, delirium in the child is evidence either of digestive derangement, of the febrile state, or of some altered condition of the blood such as obtains in the acute specific fevers. In ex ceptional cases a transient delirium may be due to mere weakness, and may be seen on the subsidence of pyrexia at the end of an attack of acute febrile disease. In such a case it disappears at once when the child is
spoken to and he answers perfectly rationally. Early and pronounced delirium, accompanied by a high temperature, is very commonly induced by croupous pneumonia ; and in any illness beginning with such symp toms it is to this disease that our thoughts would naturally turn.
Drowsiness, with dilated pupils, passing into stupor, is often a sign of intra-cranial mischief. After a fit of convulsions from reflex irritation, the child may be drowsy for an hour or two ; but unless congestion of the brain have supervened and effusion of fluid have taken place into the skull cavity, it is a symptom which in such a case soon passes away. If the fits are frequently repeated, and in the intervals the child is heavy and stupid, with large sluggish pupils ; if he takes no notice of familiar faces ; and especially if the temperature is high, and there are signs of headache, the case is probably one of meningitis.
It must, however, be borne in mind that drowsiness approaching even to stupor may be present without being due to a cerebral lesion. Certain cases of pneumonia in the child are accompanied by stupor without the temperature being extraordinarily elevated, and may give rise to strong suspicions of cerebral, disease. In such cases there is often little to attract attention to the chest, and all the symptoms point to the brain as the part affected. So, also, at the beginning of certain fevers, in urmmia, and even in some cases of severe gastric disturbance there may be great drowsiness and stupor, although there is uo lesion of the brain.
Loss of consciousness is not easy to detect in infants. The popular test is the capability of recognising a familiar face. If the baby no longer "takes notice," he is thought to be unconscious. But it must be remem bered that impairment of sight is an early symptom of tumour of the brain, and may be present in other forms of cerebral disease. A child, therefore, may cease to recognise objects and faces because his sight and not his intelligence is defective. In all cases of unconsciousness or sup posed unconsciousness it is important to notice if the child still takes liquid food. An infant, if his stupor is profound, or if he is suffering pain in the head or elsewhere, refuses his food ; while, if he is only stupid and drowsy, without being completely comatose, and is in no pain, he will often take his bottle with avidity. In cerebral haemorrhage and serous effusion a child sucks well from the bottle. When he is tortured with ear ache or abdominal colic, he refuses all food while the pain lasts ; and a child suffering from meningitis can only be fed with great difficulty.