Acute and Chronic Disease Reports
Open Access

Pathophysiology Involved in Various Types of Encephalitis

Kishore Varma^{* *}Correspondence: Dr. Kishore Varma, Department of Pulmonary and Critical Medicine, Oregon Health and Sciences University, Portland, USA, Email:

Author info »

Description

Inflammation of the brain is encephalitis. In addition to bacteria, fungi, and parasites, encephalitis can be brought on by viruses including the rabies and herpes simplex viruses. Autoimmune conditions and specific drugs are additional factors. The aetiology is still mostly unknown in many cases. Immune system weakness is one of the risk factors. Blood tests, medical imaging, and cerebrospinal fluid analysis are frequently used to support the diagnosis, which is normally made primarily on symptoms. Vaccines can stop some types from occurring. Corticosteroids, anticonvulsants, and antiviral drugs (like acyclovir) may all be used in the course of treatment.

Symptoms and indications

Adults who have encephalitis typically exhibit sudden onset fever, headache, confusion, and occasionally seizures. Children who are younger or new-borns may exhibit irritability, low appetite, and fever. Typically, neurological tests show a sleepy or disoriented person. A stiff neck, caused by inflammation of the meninges protecting the brain, is a sign of meningitis or meningoencephalitis in the patient.

Cause

Viral: Viral encephalitis can develop as one of the after effects of a latent infection or as a direct result of an acute infection. Although the cause of viral encephalitis in the majority of cases is unknown, herpes simplex infection is the most frequently recognised cause of viral encephalitis. Rabies, polio, and measles viruses are additional causes of acute viral encephalitis.

pathogenic and significant: It can be brought on by a bacterial illness, such as bacterial meningitis, or it could be a consequence of the infectious disease syphilis that is currently rife (secondary encephalitis). People with weakened immune systems are also susceptible to developing encephalitis from certain protozoal or parasite infestations, such as toxoplasmosis, malaria, or primary amoebic meningoencephalitis. Encephalitis can also be brought on by Lyme disease or Bartonella henselae. The meninges of some bacteria, such as Mycoplasma and those that cause rickettsial illness, become inflamed, which leads to encephalitis.

Acute diffuse encephalitis that is demyelinated is one aetiology that is not infectious.

Inflammatory encephalitis: The term limbic encephalitis describes an inflammatory condition that only affects the limbic system of the brain. Clinical manifestations frequently include disorientation, lack of inhibition, memory loss, convulsions, and abnormal behaviour. The medial temporal lobes and, occasionally, other limbic structures exhibit T2 hyper intensity in MRI images. There are some autoimmune causes of limbic encephalitis.

Chronic encephalitis: Catatonia, psychosis, aberrant movements, and disruption of the autonomic nervous system are some of the symptoms of autoimmune encephalitis. Rasmussen encephalitis and antibody-mediated anti-N-methyl-D-aspartatereceptor encephalitis are instances of autoimmune encephalitis. The most prevalent autoimmune form of anti-NMDA receptor encephalitis, which affects 58 percent of women between the ages of 18 and 45, is accompanied by ovarian teratoma.

Lethargic encephalitis: Lethargy, a high fever, a headache, and a delayed physical response are all signs of encephalitis lethargica. The aetiology of encephalitis lethargica is unknown; however symptoms can include tremors, muscle discomfort, and paralysis in the upper body. Encephalitis lethargica was on the rise everywhere from 1917 to 1928.

Diagnosis

Only those who have experienced lethargy, a change in personality, or a decreased or altered level of consciousness for longer than 24 hours should be considered to have encephalitis. Several tests can be used to determine whether someone has encephalitis:

1) An MRI brain scan can diagnose inflammation and rule out other potential reasons.

2) Encephalitis will result in an aberrant signal on an EEG, which monitors brain activity.

3) A lumbar puncture (also known as a spinal tap) is a procedure that uses cerebral-spinal fluid taken from the lumbar area to perform a test to identify.

4) Blood test

5) Analysis of urine

Prevention

People who are at risk should think about getting vaccinated against tick-borne and Japanese encephalitis. For all intents and purposes, smallpox is nearly eradicated, making post-infectious encephalomyelitis a complication of vaccination against it, avoidable. Patients with encephalitis should be watched out for vaccination against pertussis contraindications.

Treatment

For the treatment of Toxoplasmic Encephalitis (TE), which is brought on by Toxoplasma gondii and can be fatal in those with weakened immune systems, pyrimethamine-based maintenance therapy is frequently employed. The likelihood of recurrence in individuals with HIV with TE is reduced from around 18% to 11% when Highly Active Anti Retroviral Therapy (HAART) is combined with the well-established pyrimethamine-based maintenance medication. This is a critical distinction since relapse may affect the severity and prognosis of the disease and raise healthcare costs. It is unknown if intravenous immunoglobulin is beneficial in treating paediatric encephalitis.

Due to a paucity of randomised double-blind studies with adequate patient numbers and follow-up have been unable to come to any definitive findings. When compared to a placebo (fake treatment), intravenous immunoglobulin for Japanese encephalitis didn't seem to be any more effective.

Epidemiology

7.4 new instances of acute encephalitis are reported annually per 100,000 inhabitants in Western nations. The incidence is 6.34 per 100,000 individuals per year in tropical nations. With roughly 250,000 occurrences each year from 2005 to 2015 in the US, the number of encephalitis cases has not changed significantly over time. During this time, there were seven cases of encephalitis hospitalised in the US per 100,000 persons. According to estimates, encephalitis killed 150,000 people worldwide in 2015 and infected 4.3 million people. An annual incidence of 2-4 cases per million people is reported for herpes simplex encephalitis.