encephalitis

encephalitis
encephalitic /en sef'euh lit"ik/, adj.
/en sef'euh luy"tis/, n. Pathol.
1. inflammation of the substance of the brain.
2. Also called encephalitis lethargica /li thahr"ji keuh/. a form of this condition, caused by a filterable virus and characterized by apathy and abnormal sleepiness; sleeping sickness.
[1835-45; ENCEPHAL- + -ITIS]

* * *

Inflammation of the brain, most often due to infection, usually with a virus.

One class of encephalitis (including multiple sclerosis) attacks the myelin sheath that insulates nerve fibres rather than the neurons themselves. In most cases, symptoms include fever, headache, lethargy, and coma. Convulsions are most common in infants. Characteristic neurological signs include uncoordinated, involuntary movements and localized weakness. The symptoms and a lumbar puncture (to obtain cerebrospinal fluid for analysis) may establish the presence but not the cause. Treatment usually aims to relieve the symptoms and ensure quiet rest. Various symptoms may remain after recovery.

* * *

plural  encephalitides 

      from Greek enkephalos (“brain”) and itis (“inflammation”), inflammation of the brain. Inflammation affecting the brain may also involve adjoining structures; encephalomyelitis is inflammation of the brain and spinal cord, and meningoencephalitis is inflammation of the brain and meninges (the membranes covering the brain). Encephalitis is most often caused by an infectious organism and sometimes by such noninfective agents as chemicals, including lead (lead poisoning), arsenic (arsenic poisoning), and mercury (mercury poisoning). Although encephalitis can be produced by many different types of organisms, such as bacteria, protozoans (protozoan), and helminths (worms), the most frequent causal agents are viruses (virus). The encephalitis-producing viruses are divided into two groups: (1) those that invade the body and produce no damage until they are carried by the bloodstream to the nerve cells of the brain (e.g., the rabies and arthropod-borne viruses) and (2) those that invade the body and first injure nonnervous tissues and then secondarily invade brain cells (e.g., the viruses causing herpes simplex, herpes zoster, dengue, acquired immune deficiency syndrome [ AIDS], and yellow fever).

      Symptoms common to most types of encephalitis are fever, headache, drowsiness, lethargy, coma, tremors, and a stiff neck and back. Convulsions may occur in patients of any age but are most common in infants. Characteristic neurological signs include uncoordinated and involuntary movements, weakness of the arms, legs, or other parts of the body, or unusual sensitivity of the skin to various types of stimuli. These symptoms and signs and an examination of the cerebrospinal fluid by a lumbar puncture (spinal tap) can usually establish the presence of encephalitis, but they do not necessarily establish the cause, which often remains unknown. This makes specific treatment difficult, and, even when the causative virus is known, there may be no effective treatment. Treatment of encephalitis is therefore largely supportive. Patients require intensive medical care, with continuous monitoring of their heart and respiratory functions and management of their fluid and electrolyte balances. Symptoms remaining after recovery from the acute phase of brain inflammation vary considerably, depending on the type of encephalitis and on the age and general health of the patient. Many individuals are weak and debilitated after an attack but recover with no serious effects. Some encephalitides may cause irreparable brain damage. Prognosis depends upon the specific viral agent that caused the encephalitis; mortality can be as high as 70 percent.

      A large number of acute encephalitides are of the type known as demyelinating encephalitis, which may develop in children as a complication of such viral diseases as measles or chickenpox or as a result of vaccination against such viral diseases as smallpox. Damage to the nerve cell body does not occur, but the insulation (myelin sheath) surrounding the nerve fibres is gradually destroyed.

      Encephalitis lethargica, or sleeping sickness (to be distinguished from African sleeping sickness, or African trypanosomiasis), occurred in epidemics in Europe and in the United States about the time of World War I but has not been reported since 1930, although certain individuals may rarely exhibit residual symptoms (postencephalitic Parkinsonism). The causative agent of sleeping sickness was never established, although the influenza virus was suspected.

* * *


Universalium. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Encephalitis — is an acute inflammation of the brain, commonly caused by a viral infection. It can be caused by a bacterial infection such as bacterial meningitis spreading directly to the brain (primary encephalitis), or may be a complication of a current… …   Wikipedia

  • Encephalitis — En*ceph a*li tis, n. [NL., from Gr. egke falos the brain + itis.] (Med.) Inflammation of the brain. {En ceph*a*lit ic}, a. [1913 Webster] …   The Collaborative International Dictionary of English

  • Encephalītis — (griech.), Gehirnentzündung; Encephalocele, Gehirnbruch; Encephalomalacie, Gehirnerweichung; Encephalopathie, Gehirnkrankheit …   Meyers Großes Konversations-Lexikon

  • Encephalitis — vgl. Enzephalitis …   Das Wörterbuch medizinischer Fachausdrücke

  • encephalitis — 1843, from medical L. encephalon (from Gk. enkephalos brain, lit. within the head, from en in + kephale head ) + ITIS (Cf. itis) …   Etymology dictionary

  • encephalitis — ► NOUN ▪ inflammation of the brain. DERIVATIVES encephalitic adjective. ORIGIN from Greek enkephalos brain …   English terms dictionary

  • encephalitis — [en sef΄ə līt′is, en΄sefə līt′is] n. [ ENCEPHAL(O) + ITIS] inflammation of the brain encephalitic [en sef΄əlit′ik] adj …   English World dictionary

  • Encephalitis — Inflammation of the brain. Encephalitis occurs, for example, in 1 in 1,000 cases of measles. It may start (up to 3 weeks) after onset of the measles rash and present with high fever, convulsions, and coma. It usually runs a blessedly short course …   Medical dictionary

  • encephalitis — n. inflammation of the brain. It may be caused by a viral or bacterial infection or it may be part of an allergic response to a systemic viral illness or vaccination (see encephalomyelitis). Viral encephalitis is endemic in some parts of the… …   The new mediacal dictionary

  • Encephalitis — Klassifikation nach ICD 10 G04 Enzephalitis, Myelitis und Enzephalomyelitis G04.2 Bakterielle Meningoenzephalitis und Meningomyelitis, anderenorts nicht klassifiziert …   Deutsch Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”