encephalitiscia
- 1. ENCEPHALITIS
- 2. WHAT IS ENCEPHALITIS? Acute inflammation of the brain. Children, elderly and those with a weak immune system are those who are more prone to encephalitis. The treatment given and the chances to recovery depend completely on the virus involved and how severe the inflammation is. Acute – encephalitis : affects brain directly
- 3. CAUSES The exact cause of encephalitis is unknown. Usually caused by a virus or sometimes even a bacterial infestation as well as non infectious inflammatory conditions may cause encephalitis . Few viruses that may be instrumental in causing encephalitis includes – 1)Herpes simplex 2) Polio viruses 3)Mosquito – borne viruses 4)Tick – borne 5) Rabies 6) childhood viruses
- 4. RATE OF INCIDENCE There were no studies that specifically addressed the incidence of encephalitis. However, there were studies from various countries that mentioned the incidence of encephalitis in different settings. Those studies suggested of 1.77 to 6.34 for tropical countries and an IR of 0.51-7.4 for Western industrialized countries. An IR of 145-185 was recorded during an epidemic in Nepal in 1997. A hospital-based study from Andhra Pradesh, India, suggested an IR of 1. A review article suggested that the minimum IR must be fixed at 6.0 based on earlier studies
- 5. Biological Base • Just as a thief with a copied key can open a lock that is not his, a virus begins to enter a cell via a similar type of crime. • Outermost layer of virus has special protiens that latch onto a cell and “pick” the molecular locks on its surface. • These locks, which cover the surface of a cell, are called receptors.
- 6. • When there is no virus, receptors are used to convey important signals from the outside world to the inside of the cell. • Unrelated viruses can attach (bind) at different times to the same kind of receptor on a cell surface. • A virus’s preference for infecting a certain type of cell (like a neuron) is called tropism, and is caused by the specific interaction of the virus with a receptor found on that kind of cell.
- 7. • In addition to binding to a cell surface receptor, a virus often has to bind to a second cell surface receptor, called co-receptor. In these cases, its only after this second interaction that a virus can enter into a cell.
- 9. • Infectious encephalitis • Autoimmune encephalitis • Chronic encephalitis • Limbic encephalitis • HIV encephalitis • Encephalitis Lethargica
- 10. Infectious Encephalitis • Viruses are the most common agents that cause Infectious Encephalitis. Within the British Isles herpes simplex virus (the cold sore virus) is the virus most frequently identified. • Some of the known types of Infectious Encephalitis are: o Herpes Simplex Encephalitis o West Nile Encephalitis o Tick Borne Encephalitis o Japanese Encephalitis
- 11. Autoimmune Encephalitis • Autoimmune Encephalitis may be triggered by infection in which case the term "Post-infectious Encephalitis" is used. ADEM( Acute Disseminated Encephalomyelitis ) is a Post-infectious Encephalitis. The illness usually follows in the wake of a mild viral infection (such as those that cause rashes in childhood) or immunisations. Typically there is a delay of days to two to three weeks between the triggering infection and development of the Encephalitis. • It has recently been recognised that there are other types of Autoimmune Encephalitis resulting from an attack of the brain by the body's immune system.
- 12. Limbic Encephalitis • The term ‘Limbic Encephalitis’ (LE) is used when the limbic areas of the brain are inflamed (swollen) and consequently not functioning properly.
- 13. HIV Encephalitis Human Immunodeficiency Virus (HIV) can affect the brain in different ways. • HIV-meningoencephalitis is infection of the brain and the lining of the brain by the HIV virus. It occurs shortly after the person is first infected with HIV and may cause headache, neck stiffness, drowsiness, confusion and/or seizures. • HIV-encephalopathy (HIV-associated dementia) is the result of damage to the brain by longstanding HIV infection. It is a form of dementia and occurs in advanced HIV infection. • Mild Neurocognitive Disorder is problems with thinking and memory in HIV, however is not as severe as HIV-encephalopathy. Unlike HIV-encephalopathy it can occur early in HIV infection and is not a feature of Aquired Immune Deficiency Syndrome - AIDS.
- 14. Encephalitis Lethargica • Encephalitis Lethargica (EL) is a serious sporadic form of Encephalitis. • a form of encephalitis caused by a virus and characterized by headache and drowsiness leading to coma. • The term "sleeping sickness", where people seem to fall asleep or freeze whilst eating or working was first used to describe two cases in Vienna.
- 15. SYMPTOMATOLOGY
- 16. Initial Signs • Headache • Malaise • Anorexia • Nauseaand Vomiting • Abdominal Pain
- 17. S ymptoms • Fever • Headache • Behavioral changes • Altered level ofconsciousness • Focalneurological deficits • seizures
- 18. Developing Signs
- 21. Possible Complications • Permanent brain damage may occur in severe casesof encephalitis. It canaffect: Hearing Memory Muscle control Sensation Speech Vision
- 22. DIAGNOSIS
- 23. DIAGNOSIS • Because the various types of encephalitis produce similar symptoms, doctors cannot rely on clinical features to differentiate among the many causes of brain inflammation. The primary objective in diagnosing viral encephalitis is to determine if it is caused by: • Herpes simplex or other conditions that can be treated with specific medications • Arbovirusesorothervirusesthat can be managed only by targeting symptoms
- 24. IMAGING TECHNIQUES • For suspected encephalitis scanning technique is often the first diagnostic step. • Computerized tomography (CT)or magnetic resonance imaging (MRI)scans can show the extent of the inflammation in the brain and help differentiate encephalitis from other conditions. MRIs are recommended over CT scans because they can detect injuries in parts of the brain that suggest infection with herpes virus at the onset of the disease, while CT scans cannot. • Electroencephalogram (EEG),which records brain waves, may reveal abnormalities inthetemporal lobe that are indicative of herpes simplex encephalitis.
- 25. CEREBROSPINAL FLUID TESTS • When encephalitis is suspected, a sample of cerebrospinal fluid istaken using a lumbarpuncture. • The sample istaken to count white blood cells and identify specific blood cell types, to measure proteins and blood sugar levels, and to determine spinal fluid pressure. • Doctors use CSF to test for herpes simplexvirus,Epstein- Barrvirus,varicella-zoster virus,enteroviruses, and to look for the presence of antibodies to the WestNile virus. • While cerebrospinal fluid tests may help diagnose encephalitis, they cannot provide information on how severe the diseasewill be.
- 26. BLOOD TESTS • Blood tests may be used to test for West Nile virus and other arbovirusinfections. • Blood and urine tests are used to isolate and identify viruses. • Enzyme-linked immunosorbentassays (ELISA), including IgM-capture ELISA(MAC-ELISA) and IgG ELISA, can identify viruses that cause encephalitis soon after infection. • Polymerase chain reaction (PCR) can identify small amounts of viralDNA.
- 27. BRAIN BIOPSY • Tiny samples of brain tissue are surgically removed for examination and testing for the presence of the virus. • Tissue is prepared usingstaining techniques and then viewed under an electron microscope. • In a few cases, the viruses in brain cells are able to be cultured; that is, the viruses can actually be made to replicate in samples. • A brain biopsy is thegold standard fordiagnosing rabies.
- 28. TREATMENT • The goals of treatment are to provide supportive care (rest, nutrition, fluids) to help the body fight the infection, and to relieve symptoms. Reorientation and emotional support for confused or delirious people may be helpful. Medications may include: • Antiviral medications, such as acyclovir (Zovirax)and • • • • • foscarnet (Foscavir) --to treat herpes encephalitis or other severe viral infections (however, no specific antiviral drugs are available to fight encephalitis) Antibiotics --if the infection is caused by certain bacteria Anti-seizuremedications (such as phenytoin) --to prevent seizures. Steroids(suchas dexamethasone) --to reduce brain swelling (in rare cases) Sedatives --to treat irritability or restlessness Acetaminophen --for fever and headache.
- 29. TREATING PROBABLECAUSES OF ENCEPHALITIS • Since it isdifficulttodetermine thecause of encephalitis, and rapid treatment isessential, clinical guidelines recommend immediately administering intravenously the antiviraldrug acyclovir without waiting to determine the cause of the illness. • Once the doctor receives results from diagnostic tests, drug treatment depends on the cause of the encephalitis. Antiviral drug treatments for specific causes of encephalitis include: • • • Herpes Simplex Virus . Acyclovir isrecommended. Varicella-Zoster Virus . Acyclovir isrecommended. Ganciclovir or adjunctive corticosteroids may also be considered. Epstein-Barr Virus . Corticosteroids may be used, although risksmay outweigh benefits. (Acyclovir isnot recommended.) • For bacterial meningitis,antibiotics (notantiviraldrugs)are used.
- 30. ADDITIONAL TREATMENTS • Other encephalitis treatments are aimed at reducing symptoms. • Seizures may be prevented by using oral anticonvulsant drugsorintravenous lorazepam (Ativan). • Sedatives may beprescribed for irritability or restlessness. • Simple pain relievers may be used for fever and headache.
- 31. Prognosis • Acute phase of illness different from person to person • Some recover with slight disability, others profound disability and a few need residential care for a life time • Degree and type of damage cause of inflammation severity of the infection area affected delay in seekingtreatment
- 32. Recent trends Extensivefrontalgray mattervolume reduction related toa possible sequalae ofencephalitis (Evernsel&etal, 2015) 39 year old man Normal growth till 2years At 2, a febrile illness with convulsions- unconscious for a week. No treatment given Could walk only at 5, no speech, lacking self-care, disorganized behavior and mental retardation Untreated encephalitis at 2 years damaged frontal region
- 36. Thank You