L4 Chickenpox and Meningitis PDF

Chickenpox and Meningitis Assist prof. Rasha Ahmed M.B. Ch. B F.I.B.M.S Family Medicine  Objectives of the lecture 1. To know the type, the causative agent of the infections, and the mode of transmission 2. Epidemiology of the infections 3. Important signs and symptoms and complications of i...

Chickenpox and Meningitis Assist prof. Rasha Ahmed M.B. Ch. B F.I.B.M.S Family Medicine  Objectives of the lecture 1. To know the type, the causative agent of the infections, and the mode of transmission 2. Epidemiology of the infections 3. Important signs and symptoms and complications of infections 4. Strategies for prevention and control of infections with specific emphasis on vaccination 2 Chicken pox  Is a common illness among children, particularly those under the age of 12. An itchy rash of spots that look like blisters can appear all over the body and may a companied by flu – like symptoms. Causative agent Human herpes virus 3 (Varicella – Zoster virus) (VZV) which is a member of Herpes virus group. - A person usually has only one episode of chicken pox, but (VZV) can lie dormant within the body and cause different type of skin eruption later in life called shingles (herpes zoster). 4  Mode of Transmission From person to person by direct contact. Droplet or airborne spread of vesicle fluid or secretions of the respiratory tract. Indirectly through articles freshly solid by discharges from vesicles. Incubation period: from 2 to 3 weeks. Period of communicability Chicken pox is contagious from about 2 days before the rash appears and lasts until all the blisters are crusted over 5  Complication Chickenpox is a mild Illness but can affect some infants, teens, adults, and people with weak immune systems more severely. Some people can develop serious bacterial infections involving: Skin. Lung. Bone and joint. Brain (encephalitis). Even children with normal immune systems can occasionally develop complications, most commonly a skin infection near the blisters. 6  Chicken pox and pregnancy If a pregnant woman who hasn't had chicken pox in the past ,contract it (especially in the 1st 20 weeks of pregnancy), the fetus is at risk for congenital varicella syndrome (affect newborn may have a low birth weight and characteristic abnormalities of skin, arms, legs, hands, feet, the brain and the eyes) and the severity of infection depending upon when the maternal infection occurred during fetal development. 7 If she develops chicken pox just before or after the child is born, the newborn is at risk for severe generalize chicken pox. There is no risk to developing baby if the woman develops shingles during pregnancy. A pregnant woman who had chicken pox before pregnancy, her baby will be protected from infection for the first few months of life. 8  Prevention Immunization against chicken pox by giving live attenuated varicella virus vaccine 0.5 ml (SC) dose of age 12-15 months old and booster shot at 4-6 years old. The vaccine is about 70% to 85% effective at preventing mild infection and more than 95% effective in preventing moderate to sever forms of the infection Although the vaccine works pretty well, some children who are immunized still will get chicken pox, but will have much milder symptoms. Healthy children who had chicken pox usually develop life long protection. 9  Control 1. Report to the local health authority. 2. Isolation: exclude children from school until vesicles become dry, usually after 5 days. 3. Concurrent disinfection of articles soiled by discharge from nose, and throat. 4. Protection of contacts: the vaccine is recommended for use in susceptible persons following exposure to varicella. Varicella Zoster immuno-globulin (VZIG) given within 96 hours of exposure may prevent or modify the disease in susceptible close contacts of cases. VZIG indicates for certain high-risk person exposed to chicken pox including: 10 New born of mothers who develop chicken pox within 5 days prior to or within 48 hours after delivery. Children who are receiving drugs that suppress the immune system. People with leukemia or immune deficiencies 5.Investigation of contact and source of infection. 6.Treatment of the cases. 11 MENINGITIS 12 1. Viral meningitis: Relatively common but rarely serious clinical condition. It is caused by a variety of infectious agents, many of which are associated with other specific diseases. In about 50%, the etiology can not be identified. Important viruses are: a. Mumps virus is responsible for most epidemics (more than 25%) in nonimmunized populations. b. Enteroviruses. c. Coxsackievirus group B d. Echovirus. e. Other viruses ( poliovirus, measles virus) 14 2. Bacterial meningitis. This is a more serious disease and the main causes are: a. Neisseria meningitides causing meningococcal meningitis. b. Pneumococcal pneumoniae causing pneumococcal meningitis c. Hemophilus influenzae serotype B causing haemophilus meningitis. Bacterial Meningitis Facts Bacterial meningitis is 1 of the top 10 infectious causes of death worldwide, according to the CDC. Half of the survivors suffer neurological damage and/or other permanent side effects.  Most episodes of acute bacterial meningitis occur in previously healthy persons, special higher risk groups are: People with a fractured skull. People with primary antibody or complement deficiency. People with sickle cell disease. Neonates. The spread of infection is usually by droplets (respiratory droplets) favored by overcrowding. It may follow blood-borne spread from the upper or lower respiratory tract. S. pneumoniae and H. influenzae are usually secondary to infection elsewhere in the body. 16 Signs and symptoms  Fever Other key symptoms Severe headache Petechial or purpuric rash Nasua and vomiting Rapid breathing  Fatigue and lethargy Kerning's sign  Neurological symptoms Brudzinski's sign  Neck stiffness  Altered mental status  Photophobia  Seizers 17 Neurological Complications 1. Seizers 2. Hearing loss 3. cognitive impairment 4. Hydrocephalus 5. Cranial nerve damage 6, Stroke 7. Brain abscess Systemic complication 1. Septic shock 2. Disseminated intravascular coagulation(DIC) Multiorgan failure Two main barriers protect the meninges from being infected. A surface defense mechanism of the nasopharynx (IgA) and a bactericidal substance in the plasma. 18  Comparative epidemiology M. meningitis S. meningitis H. influenzae Reservoir man man man IP 2-10 days ? 2-4 days Transmission airborne airborne airborne Communicability As long as microorganisms are present in the secretions of patients. When antibiotic therapy starts, patients are usually no longer infectious to others within 24 hrs. 24-48 hrs. 24-48 hrs. Immunity: Exists but May last for Not definite Duration ? years 19  Prevention a. avoidance of close contact. b. reduction of overcrowding in living and workplaces). c. Immunization is of limited application except for M. meningitis d. Chemoprophylaxis:( rifampicin, ceftriaxone, ciprofloxacin, sulphadiazine). It helps to: 1. protect susceptible persons. 2. abort early clinical cases. 3. eliminate carriers. 20 Control measures 1. Notification. 2. Isolation as long as infection is likely to be transmitted to others. 3. Chemoprophylaxis for close contacts may be useful in epidemic situations. 4. Treatment of cases with appropriate antibiotics. 21