**4. Diagnostics**

The principal goal in diagnostics is to identify if the patient is indeed suffering from encepha‐ litis and then the aetiological agent of encephalitis. The most common causes of viral ence‐ phalitis are HSV and VZ encephalitis and they are the only curable causes also.

#### **4.1. EEG**

validity of this reflex clinically argued as changes in foot tapping have been shown to more

Muscle bulk can be primarily assessed by inspection. Symmetry is important, with consider‐ ation given to the dominance of the hand and overall body habitus. Generalized wasting or cachexia should be noted and may reflect systemic disease, including neoplasia. Severe atrophy strongly suggests denervation of a muscle, such as with lower motor neuron (LMN) lesions. The most common method is assessing muscle tone is passively moving the patients limb. Tone can either be decreased or increased. The two common patterns of pathologically increased tone, spasticity and rigidity[43]. We should consider the difference between spasticity and rigidity. Spasticity [44] is manifested as an increased resistance to ignition of movement proceeded with a rapid passive movement. Rigidity is an increase in tone which is

Coordination is tested as a part of a sequence of movements. Typically the patient is asked to hold his/her hands in front with the palms up, first with the eyes open and then closed (as when examining pronator drift, above). Now we should consider posture, gait and any abnormal movements. The patient should be able to stand erect with eyes open and closed to see if doing so incites abnormality in movements. Then you should ask the patient to walk and

Now we can compare the differences between upper motor neurons and lower motor neuron

efficiently show upper motor neuron (UMN) lesions[42].

seen throughout a variety of movements[45].

assess if there are any abnormalities in gait[46].

**Comparison UMN LMN**

Location of symptoms Contralateral2: pages 254 Ipsilateral 2: pages 254

Reflexes Absent 1: page 46 Present 1: page 50

Fasciculation Absent 3: chapter 9 Present3: chapter 9

Spasticity Present1: page 46 Absent1: page 50

Flaccidity Absent 2: pages 250 Present1: page 50

**Table 4.** A comparison between Upper Motor Neurons and Lower Motor Neuron lesion signs

2. Neuroanatomy text and atlas : john H. Martin third edition : 2003 McGraw-Hill

Rowland (Editor), Randy Rowland By Lippincott Williams & Wilkins Publishers

1. Adapted from: Reinhard Rohkamm, M.D., Color Atlas of Neurology, 2004 Thieme Pages 46 to 50.

3. Merritt's Neurology 10th Edition (June 2000): by H. Houston Textbook of Neurology Merritt (Editor), Lewis P.

Somatic sensation can be tested using the dermatomes. However this is completely subjective to the patient's perception. It is up to the examiner to determine if indeed there is a loss of

lesion signs (table 4)

10 Encephalitis

**3.8. Sensory system**

EEG changes in encephalopathies are similar to any encephalitis aetiological agent. There is a progressive increase in slow wave activities[47], the degree of which parallels the severity of brain dysfunction. A diffuse slow-wave background followed by the rapid development of periodic complexes in may be diagnostic of herpes-simplex encephalitis[48]. None of these patterns is specific to a particular pathophysiological process or diagnosis, but periodic epileptiform discharges are most likely to occur in an acute course of the disease[49].

### **4.2. Radiography**

MRI is the most sensitive non-invasive test in early diagnosis of HSE due to its high sensitivity to inflammatory increased brain water content. The classical findings in herpes encephalitis are periodic lateral epileptiform discharge and hyper intense T2-weighted signal in the temporal lobe on MRI however these findings are nonspecific[50]. Japanese encephalitis MRI clues would be bilateral thalamic involvement; hemorrhagic involvement can be occasionally seen. Locations in which lesions can be seen are cerebrum, the midbrain and cerebellum, the pons and the basal ganglia. The locations in which hemorrhagic lesions can be seen are cortex, the midbrain, cerebellum, and pontine lesions[51]. Eastern equine encephalitis produces focal radiographic signs what distinguishes it from HSV encephalitis involvement of the basal ganglia and thalami[52]. An MRI preformed on a patient with Epstein-Barr virus encephalitis could show focal lesions in the basal ganglia[53]. The tick-borne encephalitis MRI revealed pronounced signal abnormalities in the basal ganglia and thalamus, without contrast en‐ hancement[54]. Meningovascular syphilis can manifest T2-weighted hyper intense signal abnormalities, which are thought to represent cerebral infarctions[55].

#### **4.3. Lumbar puncture**

Lumbar puncture is indicated in a patient with suspected CNS infections (table 5).

Contraindications of lumbar puncture should be kept in mind. If the patient is showing signs of papilledema or an intracranial mass is suspected an urgent CT should be performed[56]. Local skin infections are an absolute contraindication and so are spinal deformities. Uncon‐ trolled bleeding diathesis is also a contraindication.


tion[59]. The TaqMan assay was specific for WN virus and demonstrated a greater sensitivity

The Clinical Management of the Patient with Encephalitis

http://dx.doi.org/10.5772/55171

13

The treatment is mainly focused on medical treatment as surgery is rarely required. Medical treatments rely on the assessment of the patients' needs. Prioritising clinical care is crucial as encephalitis can be life threatening so focusing treatment on jus the aetiological agent is a flaw in the clinician's judgement. Ensuring the patient's vital signs stay within a physiological range and if an aetiological agent is discovered then treatment specified for that agent should be

Encephalitis is a medical emergency. Initially as we discussed the ABCD guidelines should be followed. Then after the diagnostic steps are undertaken the patient should be isolated until

Varicella-Zoster Virus Acyclovir is recommended. Gancyclovir or adjunctive

EBV Acyclovir initially or cidofovir once EBV identified4. Herpes B virus No drug has been shown to be effective, although

1. Herpes simplex virus infections of the central nervous system: encephalitis and meningitis, including Mollaret's. 2. Antiviral Therapy of Herpes simplex and Varicella-zoster Virus Infections Peter Wutzler Institute for Antiviral

3. Cytomegalovirus infection of the central nervous system. Griffiths P. Source Department of Virology, Royal Free

6. Interferon-α protects mice against lethal infection with StLouisencephalitis virus delivered by the aerosol and

The next most common aetiological cause of encephalitis is bacterial. Neurosyphillis treatment is based on administering Penicillin at the same levels of treponemicidal levels found in

Human herpes 6 Gancyclovir or foscarnet should be used in

corticosteroids 2

valacyclovir is the preferred agent1

immunocompromised patients1

the aetiology is determined as most viral causes are airborne (table 6).

**Virus Treatment** HSV-1 and HSV-2 Acyclovir1

Cytomegalovirus Gancyclovir 3

Measles Steroid therapy 5 St. Louis Encephalitis Interferon alfa-2a 6

Chemotherapy, Clinicum of the University of Jena, Erfurt, Germany

4. Diagnosis and treatment of viral encephalitis : A Chaudhuri, P G E Kennedy 5. Treatment of measles encephalitis with adrenal steroids : John E. Allen

**Table 6.** The treatment modalities for viral aetiological agents of encephalitis.

and University College Medical School, London, UK

subcutaneous routes : T.J.G Brooks, R.J Phillpotts

than the PCR method [60].

**5. Treatment**

deployed.

**5.1. Medical treatment**

2. Role of Local Anesthesia During Lumbar Puncture in Neonates : Joaquim M.B. Pinheiro, Sue Furdon, Luis F. Ochoa :Pediatrics Vol. 91 No. 2 February 1, 1993 pp. 379 -382

3. Choosing the best needle for diagnostic lumbar puncture : Damien Carson, MB BCh, FRCA and Michael Serpell, MB BCh, FRCA : Neurology July 1, 1996 vol. 47 no. 1 33-37

4. Lumbar Puncture : Miles S. Ellenby, M.D., Ken Tegtmeyer, M.D., Susanna Lai, M.P.H., and Dana A.V. Braner, M.D. New England Journal Med 2006; 355:e12September 28, 2006

5. Lumbar Puncture Technique: Thomas A. McLennan Canadian Medical Association Journal (1962) Volume: 86, Issue: 17, Pages: 789

**Table 5.** A step by step method of performing a lumbar puncture.

Once CSF is obtained test tube one sample is usually used for detecting protein and glucose levels. Test tube 2 is used to establish a possible etiological agent so can be used for serology and bacterial cultures. Test-tube 3 is used to establish cell count and finally test-tube 4 is reserved for any specifics tests.

#### **4.4. Serology**

Once you have a CSF sample it can be used to preform serology tests in order to identify any possible viral causes of encephalitis.

As the most common causes of encephalitis are viral, serology is a useful tool for diagnosis the aetiological agents of encephalitis. Routine PCR diagnosis of HSE type 1 and 2 is a highly sensitive and specific method for diagnosing encephalitis[57]. The identification of West Nile virus immunoglobulin M in cerebrospinal fluid is the recommended test to document central nervous system infection, but this test may not be positive in spinal fluid collected less than 8 days after the onset of symptoms[58].For the diagnosis of JE virus (JEV) infection an immu‐ noglobulin M capture dot enzyme immunoassay can distinguish JEV from dengue infec‐ tion[59]. The TaqMan assay was specific for WN virus and demonstrated a greater sensitivity than the PCR method [60].
