When the inflammation is situated in the meseneephalon or medulla oblongata instead of in the hemispheres, it gives rise to certain clinical conditions which deserve special deseription.
Wernicke first described a symptom-complex which has since been designated aeute bientorrhagie superior polien.cephalitis. A short pro dromal period, marked by headache, vomiting and vertigo, is followed by hebetude, rigidity of the neck, ocular palsies, disturbance of the gait and ataxia. As a rule there is no fever. The course of the disease is progressive. Death usually occurs in from 1 to 2 weeks. The causes of this condition are believed to be alcoholism and infectious diseases (influenza). Post inortena, acute latemorrhagic inflammation of the gray matter in the third ventricle and in the aqueduct of Sylvius, extend ing over into the fourth ventricle, has been observed. In children this form of encephalitis is rare.
When the acute inflammatory process is situated in the central portions of the medulla oblongata nearer the spinal extremity, the symptoms are those of an acute in ferior poliencephalitis. The bulbar nerves, that is, the facial, hypoglossus, vagus, and spinal accessory, are chiefly involved. Disturbances of speech, dysphagia, interferenee with the movements of the mouth and tongue, aphonia, disturbance of the pulse and respiration, dribbling of saliva, hysterical laughing, and crying are present. It is needless to say that if the inflammation is so extensive as to involve all the nuclei of the cranial nerves, the symptoms of a superior and inferior nuclear palsy are combined; and if the process also involves the pyramidal tract, hemiplegia, monoplegia, tremor and intention tremor develop. A severe inflammation of this kind affecting the bulbar region, which occurs chiefly after infectious diseases and as the result of poisons but may-, like poliomyelitis, develop spontane ously, usually terminates fatally, recovery with permanent symptoms being a rare event (Kollarits). It is worthy of note, however, as show ing the analogy with doubtful forms of encephalitis resembling brain tumors, that even an acute bulbar affection may run a tnild course and end in complete recovery (as for example, after meat and sausage poisoning). Whether in eases of this kind inflammation or changes
resembling inflammation are actually present is difficult to decide, particularly as acute fatal bulbar affections sometimes exhibit no post mortem lesion except possibly aggregations of micrococci in the portions of the brain supposed to be diseased.
Finally, we should devote a special paragraph to disseminated mycloencephalitis. In this affection, multiple inflammatory foci are produced in the brain, medulla oblongata and spinal cord, which may run an acute, subacute or chronic course. The cause is in aIl probability to be sought in the infectious diseases. The symptoms are extremely variable consisting as they do in a combination of symptoms referable to the cranial and bulbar nerves and disturbanees in the extremities grouped without any apparent order. Either the cerebral or the spinal symptoms may predominate, and the clinical pieture may- be chiefly that of a cerebral infantile palsy, of a bulbar affection or of a poliomye litis. A number of observers have contributed post-mortem proofs of this widespread disease, which extends over the entire central nervous system (Redlich, Schupfer and others). The terminal stage of the disease is a condition in which disturbance of speech and of the intelligence, tremor and spasm are the most prominent symptoms. The picture of a multiple sclerosis may thus be simulated. Indeed, it is not too much to say that most of the cases diagnosed as multiple sclerosis in child hood represent the remains of circumscribed inflammations in the brain and spinal cord which have ended in recovery.
The differential diagnosis froni multiple sclerosis is based on the history of some infectious diseases, the acute onset, and on the arrest of symptoms or, in other words, the failure of the disease to progress steadily. Post mortem the remains of a former inflammation are found instead of, as iu multiple sclerosis, the formation of neurogliar tissue exclusively.