ENCEFALITE VIRAL HERPÉTICA FOR THE VIRUS OF THE HERPES

ENCEFALITE VIRAL HERPÉTICA FOR THE VIRUS OF THE HERPES


Introduction

The encefalite provoked for human Herpesvírus 1 (HSV), or other viruses of the subfamília Alphaherpesviridae, is a relatively uncommon illness, however of gravity many times preoccupying had to the high degree of morbimortalidade. The main causer of herpética encefalite, in adults, is the HSV-1. However, in neonatais infections, it must be thought mainly about a acometimento for the HSV-2.
The HSV-1 is a capable virus of if keeping of latent form in ganglia medulares. About 90% of the adult population it shows positive sorologia for exposition to this patógeno. In some cases, mainly in occasions of fall of the imunológico state (for it estresse, for example), injuries ulceradas in the labial mucosa can appear of carriers of latent infection for this virus.

The etiopatogenético mechanism of the herpética encefalite well is not known, being attributed multiple determinative factors to it. The herpética encefalite can appear in such a way through primary infection for the HSV how much for latent infection.
The encefálico comprometimento predominates in the cinereous substance, but it also reaches the white substance, being very common in the medial portion of the secular wolf, wolf frontal and límbico system. In general, the acometimento is bilateral, but some patients can show an anti-symmetrical standard. The characteristic alterations are folloied petequiais hemorrhages of necrosis in the involved small farms.

Clinical and Disgnostic

Initially, is important to have science of that the clinical picture of the illness can be acute or subagudo. The patients present fever (despite about 10% of the patients they can attend a course afebris), intense chronic headache, mannering alterations of the conscience level and (psicomotora agitation is common), and focal or generalized convulsions. Déficits motor can occur but they are not common.
It must be intent to the fact of that many of the symptoms that follow the illness are common in psychiatric patologias, as alterations of the level of conscience with deliriums, disorientation, alterations of personality and psicomotora agitation; thus, the guiding maken a mistake to the psychiatrist can compromise the correct treatment irremediably.
The diagnosis of the herpética encefalite possesss controversial aspects extremely, a time that the definitive diagnosis only can be given through cerebral biópsia. This procedure, however, demonstrates little importance in the practical one, a time that the therapeutical empiricist attends a course with insignificant collateral effect and methods of image as the more sensible and specific magnetic resonance if has become each time.
The nuclear magnetic resonance is an excellent method of image, mainly the T2 sequences, to identify cerebral alterations caused by the HSV. A new form of sequence meets in studies that raises the especificidade of the magnetic resonance for the detention of herpética encefalite, called “diffusion-weighted (DW). The computerized cat scan can be used, however the false-negative tax can arrive 40%.
The examination of the cefalorraquidiano liquid extracted by lumbar punção also is important, mainly to discard possible distinguishing disgnostic as bacterial meningite for enterovírus or. Great part of the patients presents pleocitose has led, with proteinorraquia discrete increased and glicorraquia many times normal or little reduced.
The eletroencefalograma is a sufficiently inespecífico examination in the herpética encefalite, but it can disclose pathological standards on the acometido secular wolf in about 75% of the acometidos patients.
The sorologia for the virus simplex herpes can be made, however the result only acquires value if to confirm negatividade, being able itself to affirm then that the patient never entered in contact with the HSV. The positividade of the examination necessarily does not mean acute infection of encéfalo for the etiológico agent.

The reaction of chain of polimerase (PCR) in the líquor is extremely useful, but the high cost restricts its use.
Research of patologias that attend a course with imunodepressão, as malignant infection for the HIV and neoplasias, must receive attention in patients with herpética encefalite, mainly in return cases.

Treatment
The disgnostic suspicion of herpética encefalite it must be made in quick way, allowing that antiviral therapy can be carried through of fast form - the morbimortalidade meets related closely with the rapidity with that if it initiates the therapeutical one. The more early if it institutes the treatment, better will be the possibilities of the patient of if recouping free of sequels.
The choice drug is to aciclovir, managed for saw endovenosa (10 mg/kg of 8/8 hours), in regimen of hospital internment, during ten days. Aciclovir is a drug of few collateral effect, being generally very well tolerated for the patient. By the fact of the encefalite herpética to possess a character of high gravity if not treated correctly, its pursuing must be made with continuous medical comment in hospital scope.
In some patients, it can have return of the encefalite picture, whose etiopatogenético mechanism is not elucidated. However, one knows currently that patient with comprometimento of the imunológico system they are more inclined to have repeated pictures of herpética cerebral infection. In these cases, therapeutical more aggressive and/or drawn out it must be considered.
The prognostic of the illness depends on factors as precocious or delayed beginning of the treatment, age of the patient (people with less than thirty years of age demonstrate better recovery of what the those oldest ones), and level of conscience of the sick person (patient half-comatosos comatosos or worse show prognostic in relation to the therapeutical effectiveness).


Conclusion

 The herpética encefalite is a in such a way rare pathology one, however with great risk of sequels and even though death. These characteristics emphasize the importance of the precocious diagnosis and the treatment. The clinical picture is relatively specific and the diagnosis can be established through examination of the líquor, eletroencefalograma and magnetic resonance. Other examinations as sorologia for HSV and PCR also can be used. The cerebral biópsia for histopatológico diagnosis is reason of controversas in the current scientific way. The treatment is made with aciclovir, preferential endovenoso, per ten days. The evolution of the patient of close so that must be folloied the therapeutical control can frequently be evaluated how much to its effectiveness.