**4. Diagnosis**

virus type 1 (HSV 1) and 2 (HSV 2), is known as herpes meningoencephalitis (HME) [2]. The direct infection in the brain or meninges is called primary HME, whereas if it spreads from other parts to the brain, then it is called secondary HME. Both the male and female are affected at an equal ratio with a higher mortality and morbidity rate (∼50%) for infants. Like a communicable infection, spread through air, water, or close contact [3], the viruses after entering the patient through mouth, nose, or genital tract reach to the brain‐crossing blood‐brain

50 Meningoencephalitis - Disease Which Requires Optimal Approach in Emergency Manner

The symptoms of this infection are a combinatorial effect of both the meningitis and encephalitis insisting the physicians to suspect meningoencephalitis [4]. Symptoms resemble to the common viral infections but may vary among the children and adults. Some of the typical symptoms of HME are nuchal rigidity, blurred vision, and purple body rashes. The infection can spread among people through droplets, foods, air, or close contact. There is always a need for early diagnosis of the infection followed by treatment. The disease can be suspected initially on the basis of the specific symptoms of the patients. This can be further confirmed by several laboratory‐based, imaging, or advanced techniques [5]. Although the prevention of HME is not possible through vaccination, but proper precaution measures can reduce the risk of spreading and relapsing of the disease. Abstain or safety measures during sexual inter-

course and proper management during pregnancy lessen the risk of contamination.

symptoms, causes, diagnosis, prevention, and treatment of HME.

Mild infected persons may recover in few weeks but a severely infected person requires longer time and intense care. Early treatment of the patients with antiviral drugs may hugely reduce the risk of the contamination and death. Anticonvulsants or diuretics can minimize the inflammation, cranial pressure, or pain. In this chapter, we have discussed in detail about the

The symptoms of HME resemble to common flu and may vary among children, adults, and neonates. HME type 1 is more prominent at age below 20 years or over 40 years. The earlier symptoms shown in children and adults are fever, disorientation, or speech problem. At a later stage, headache, vomiting, fever, drowsiness, seizures, and unconsciousness also appear. Specific symptoms of this infection are nuchal rigidity, blurred vision, hallucinations, purple rashes or behavioral changes [4]. Infants are mainly infected by type 2, and the symptoms

HME is mainly caused by HSV type 1, type 2 or as secondary squeal of other diseases like Crohn's disease [2, 6]. HME accounts for about 10% of the total meningoencephalitis cases

children. The infection is contaminated through coughing, sneezing or close contact. Type 1

. Most of the HME cases are seen in case of infants or

include high fever, bulging of forehead, poor feeding or constant sleepiness.

barrier and cause infection.

**2. Symptoms**

**3. Causes**

with a effecting rate of about 2/10<sup>6</sup>

On the basis of different symptoms seen in the suspected patients, physicians suggest different preliminary or confirmatory diagnostic tests [5]. Diagnosis of the HME involves several stages, initially differentiation from other closely related infections and then distinguishes between bacterial, fungal, and viral meningoencephalitis. The final step involves confirmation of HME from other forms of aseptic meningoencephalitis. Diagnosis can be carried out from blood, saliva, urine or cerebrospinal fluid (CSF) of the patients with the CSF being preference. Diagnosis of HME is done as below:

## **4.1. Laboratory methods**

## *4.1.1. Body fluid test*

Different types of body fluids like urine, blood, or saliva of the suspected patients can be tested for antigens, antibodies, level of WBCs, proteins, procalcitonin, or glucose. These components are mainly detected through biochemical analysis or immunological assays. Increase in the WBC count in the CSF or the presence of IgM antibodies in the serum confirm HME. The level of these components confirms pathogenic condition of a person and differentiates between bacterial, fungal, and aseptic meningoencephalitis. The presence of WBCs or microorganisms turns the CSF from transparent to cloudy in color. Increase in the lymphocyte count is a characteristic of viral infection. Increase in the amount of proteins or decrease in the glucose in CSF also confirm viral infection. But biochemical analysis may be inconclusive or misleading. Therefore, further tests like PCR or blotting must be carried out for further confirmation of the specific infection. Sometimes, the samples from the patients are cultured and sensitivity tests carried out for confirmation of the pathogen [8–10]. But this consumes 2–3 days for confirmation. Microscopic analysis of the patient samples is also another alternative diagnostic method. But this is a preliminary mode of diagnosis and nonspecific.

## *4.1.2. Spinal tap*

Diagnosis using CSF through spinal tap or lumbar puncture is one of the most preferable methods to distinguish meningoencephalitis from blood toxicity or sepsis. This technique involves extraction of about 0.5–1.0 ml of CSF from the subarachnoid space between lumbar (L) vertebrae L3/L4 or L4/L5 [8]. The change in the composition of CSF, presence of pathogens or their by‐products, presence of lactic acid, lactate dehydrogenase, or C‐reactive proteins or increase in the white blood cells (WBCs) count of CSF can be detected by various methods [9, 10]. CSF‐based detection is one of the traditional methods used for the diagnosis of several disorders associated with the central nervous system. Although the method is less time consuming, it is low sensitivity and nonspecific.

#### **4.2. Non‐laboratory tests**
