A TYPICAL PRESENTATION OF HERPES SIMPLEX ENCEPHALITIS

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Barik B.K., Pardhan B, Murmu M, Sethy R.C., Bhakta S, Das A.K.

ABSTRACT:

Herpes simplex virus (HSV) encephalitis usually caused by HSV1 is gravest and commonest form of acute encephalitis. It is usually present with fever, headache, seizure, confusion, stupor and coma. Psychosis may be associated with these manifestations. Here we are reporting a case of clinico-radiologically diagnosed case of HSV encephalitis that present predominantly with psychosis and make diagnostic dilemma. (The Ind. Pract 2005; 58 (1):38-39.

KEY WORDS:

      Herpes Simplex Virus, Encephalitis, Psychosis

INTRODUCTION:

      Among all acute encephalitis 10% of cases are due to HSV. It is usually present like other acute encephalitis. Psychosis is a distinct feature due to involvement of temporal lobe, medial and orbital part of frontal lobe. CT scan imaging may identify the cerebral lesion at temporal and frontal lobe. Fatality rate varies between 30-70%. Early presumptic diagnosis with the help of clinical examination, C.S.F. examination and radio imaging and early therapeutic intervention with acyclovir may save the life of the patient. C.S.F. PCR is the diagnostic approach now for herpes simplex encephalitis.

CASE REPORT:

      A 38 year old male presented with psychotic behavior or last 20 days. He was febrile for about 6 days 2 weeks back. Fever was typically low grade, contunuosu. With the onset of fever he starts incoherent talk.

      He  was also unable to recognize the known persons. His speech frequency was very much decreased and he was reluctant to take food. He was admitted to local private hospital on days of his illness where his CS examination was done. At that time his CSF cell count was 296/cumm, mostly lymphocytes, protein 72mg% and sugar 48mg%. His treatment was started  there in the line of TB meningitis but patient gradually deteriorated. Due to his uncontrolled psychotic behavior, psychatric consultation was done, treated with haloperidol. But patient’s psychosis did not improve. Rather his bladder and bowel control was lost.

      On the day of our hospital admission patient was febrile, drowsy, disoriented, illusion and auditory hallucination were present. Sensory aphasia, inhoherent talks were associated with those features. His plantar reflex was B/L extensor and gait unsteady. Investigation revealed WBC 11100/cumm. ESR 15mm and RBS 127mg% DC – N 51% and L 49%. Repeat C.S.F. examination was done which revealed total WBC count 76/cumm mostly lymphocytes, protein 28 mg% and sugar 78 mg%. CSF contained plenty of RBC. CT scan of brain showed hypodense area at B/L temporal and fronto medial lobe (Fig. 1 and Fig 2) suggestive of HS encephalitis. Treatment was started with acyclovir 500 mg IV 8 hourly with monitoring pf S. Creatinine level. On 10^th day of therapy patient’s psychosis decreased, was able to recognize his wife and son and plantar become flexor, though auditory and gustatory hallucination still persisted.

DISCUSSION:

HSV 1 and 2 infection can manifest a spectrum of illness from stomatitis and progenitor lesion to facial nerve palsy and encephalitis. Encephalitis is due to HSV1. The unique localization of the disease in the temporal lobe may be explained by the virus  route of entry into the CNS¹. The lesion takes the form of haemorrhagic necrosis of temporal and medial part of frontal lobe². Lesion of these areas in imaging study with CT or MRI is highly suggestive³. Patients with Japanese encephalitis display abnormalities of thalamus, basal ganglia and midbrain. Other forms of viral encephalitis imaging studies are non- specific.

Manifestations like hallucination, anosmia, personality changes, bizarre behavior or delirium, aphasia usually observed in H.S. encephalitis. Temporal lobe seizure usually seen in ECG. Affection of memory can be recognized in the convalescent state.   

CSF often cloudy due to RBC as well as WBC protein may be raised but sugar usually normal. In minority of cases, low sugar in CSF may confuse with TB or fungal meningitis. Test for detection of HSV in the CSF by PCR are useful in diagnosis while virus is replicating in  first few days of illness.

Our patient presented at OPD after 3 weeks of illness when the absolute ways to establish the diagnosis is fluorescent antibody study and viral culture of brain tissue obtained by biopsy. Avoiding this hazardous procedure, we treated the patient with empirical antiviral agents based on compatible clinical, radiological and CSF findings. Treatment option  for HSE is acyclovir in the dose of 30 mg /kg/day for 10-14 days⁵. Our patient was responding well with above mentioned treatment. After one month follow up , patient improved with mild psychotic behaviour, gaustatory hallucination and depression.

REFERENCES:

1.      Davis L.E., Joshson R.T.: An explanation for localization of herpes simplex encephalitis. Ann Neural 1979; 5: 2.

2. Adams H. Miller D: Herpes Simplex encephalitis: A clinical and pathological analysis of twenty two cases. Post Grad M.D. J 1973; 49:93.
3. Davis J.M. et al : CT of herpes simplex encephalitis with clinico pathological correlation. Radiology 1978; 129:409 – 17.
4. Lakeman F.D., Whitley R.J. et al : Diagnosis of Herpes simplex encephalitis: Application of PCR to CSF from brain biopsied patient correlation with disease. J. infect disease 1995; 171: 857.