Mumps PDF

MUMPS By Dr.Elaf Yousif Beram M.B.CH.B, F.I.M.S/ FM Learning Objectives: 1. To know the causative agent of mumps. 2. To know the clinical presentation and complication of disease. 3. To know the available treatment and prevention for that disease. Background: An acute infectious...

MUMPS By Dr.Elaf Yousif Beram M.B.CH.B, F.I.M.S/ FM Learning Objectives: 1. To know the causative agent of mumps. 2. To know the clinical presentation and complication of disease. 3. To know the available treatment and prevention for that disease. Background: An acute infectious disease caused by an RNA virus of the family paramyxoviridae which has a predilection for glandular and nervous tissues. Clinically, the disease is recognized by non suppurative enlargement and tenderness of one or both the parotid glands. Other organs may also be involved. Constitutional symptoms vary, or may be in apparent. The disease occurs throughout the world. Although morbidity rate tends to be high, mortality rate is negligible. In most parts of the world, the annual incidence of mumps in the absence of immunization is in the range of 100-1000 cases/100,000 population with epidemic peak every 2-5 years. Natural infection with this virus is thought to confer lifelong protection. Agents factor: (a) AGENT : The causative agent, Myxouirus parotiditis is a RNA virus of the myxovirus family. There is only one serotype. (b) SOURCE OF INFECTION : Both clinical and subclinical cases. Subclinical cases which account for 30- 40 per cent of all cases ,appear to be responsible for maintaining the cycle of infection. The virus can be isolated from the saliva or from swabs taken from the surface of Stenson's duct. Virus has also been found in the blood, urine, human milk and on occasion in the CSF. (c) PERIOD OF COMMUNICABILITY : Usually 4-6 days before the onset of symptoms and a week or more thereafter. The period of maximum infectivity is just before and at the onset of parotitis. Once the swelling of the glands has subsided, the case may be regarded as no longer infectious. (d) SECONDARY ATTACK RATE : Estimated to be about 86 per cent. Host factors : (a) AGE AND SEX : Mumps is the most frequent cause of parotitis in children in the age group 5-9 years. The average age of incidence of mumps is higher than with measles, chickenpox or whooping cough. However, no age is exempt if there is no previous immunity. The disease tends to be more severe in adults than in children. (b) IMMUNITY : One attack, clinical or subclinical, is assumed to induce lifelong immunity. There is only one antigenic type of mumps virus, and it does not exhibit significant antigenic variation. Most infants below the age of 6 months are immune because of maternal antibodies. Environmental factors : Mumps is largely an endemic disease. Cases occur throughout the year, but the peak incidence is in winter and spring. Epidemics are often associated with overcrowding. Mode of transmission : The disease is spread mainly by droplet infection and after direct contact with an infected person. Incubation period : Varies from 2 to 4 weeks, usually 14-18 days. Clinical features : Mumps is a generalized virus infection. In 30-40 per cent of cases mumps infection is clinically non-apparent. In clinically apparent cases. it is characterized by pain and swelling in either one or both the parotid glands but may also involve the sublingual and submandibular glands. Often the child complains of "ear ache'' on the affected side prior to the onset of swelling. There may be pain and stiffness on opening the mouth before the swelling of the gland is evident. Mumps may also affect the testes, pancreas, CNS, ovaries, prostate, etc. In severe cases, there may be fever, headache and other constitutional symptoms which may last from 3-5 days. The swelling subsides slowly over 1-2 weeks. COMPLICATIONS : Though frequent, are not serious. These include orchitis , pancreatitis, meningoencephalitis, thyroiditis, neuritis, hepatitis and myocarditis. Testicular swelling and tenderness denote orchitis, which is the most common extra salivary gland manifestation of mumps in adults. It is unilateral in about 75 per cent of cases. High fever usually accompanies orchitis, which develops typically 7-10 days after the onset of parotitis in about 25-40 per cent of post- pubertal men. Bilateral orchitis is rare and the assumption that mumps orchitis may lead to sterility is ill-founded. Upper abdominal pain, nausea and vomiting suggest pancreatitis. Mumps is a leading cause of pancreatitis in children. It occurs in about 4 per cent of patients. Lower abdominal pain and ovarian enlargement suggest oophoritis which occurs in 5 per cent of post pubertal women, usually unilateral. Rarer complications include nerve deafness, polyarthritis, hydrocephalus, encephalitis. cerebellar ataxia, facial palsy and transverse myelitis. Encephalitis is associated with cerebral edema, serious neurologic manifestations and sometimes death. Up to 15% of mumps patients may develop meningitis, and a much smaller proportion may develop encephalitis. Mumps is one of the main infectious causes of sensorineural deafness. Mumps infection in the first trimester of pregnancy is associated with a 25% incidence of spontaneous abortion, although congenital malformations following mumps infection in pregnancy have not been reported. Prevention: Prevention : VACCINATION : Highly effective live attenuated vaccine is now available for the prevention of mumps. A single· dose (0.5 ml) intramuscularly produces detectable antibodies in 95 per cent of vaccines. The duration of long-term immunity is not known. It is recommended for routine immunization for children over 1 year of age, either alone or in combination with other virus vaccines, eg. in MMR vaccine or as a quadrivalent vaccine with varicella. There are no known cases of long-term sequelae associated with mumps vaccination. Countries including mumps vaccines in their national immunization program are advised by WHO to set disease control targets (control or elimination) and to design their mumps immunization strategy accordingly. Strategies to achieve mumps elimination include very high coverage with the first dose of mumps vaccine, ensuring a second opportunity for vaccination and conducting catch-up immunization of susceptible cohorts. MMR vaccine should not be administrated for the following condition: 1. Had two doses of the MMR vaccine after 12 months of age. 2.. People who have had a life-threatening allergic reaction to the antibiotic neomycin or any other component of the MMR vaccine 3. Pregnant women or women who plan to get pregnant within the next four weeks 4. People with severely compromised immune systems. Side effects of the vaccine: The MMR vaccine is very safe and effective. Getting the MMR vaccine is much safer than getting mumps. Most people experience no side effects from the vaccine. Some people experience a mild fever or rash or achy joints for a short time., children who get the MMR vaccine might experience a seizure caused by fever. But these seizures haven't been associated with any long-term problems. Control: The control of mumps is difficult because the disease is infectious before a diagnosis can be made. The long and variable incubation period, and the occurrence of subclinical cases make the control of spread difficult. However, cases should be isolated till the clinical manifestations subside. Steps should be taken to disinfect the articles used by the patient. Contacts should be kept under surveillance. Mumps surveillance : Case definitions : WHO recommends the following case definitions for mumps surveillance : a. Clinical mumps : acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, lasting 2 or more days and without other apparent cause. b. Laboratory confirmed mumps : a patient with clinical mumps and laboratory confirmation by positive mumps lgM antibody (without mumps immunization in the previous 6 weeks) or; sero-conversion with 4-fold or greater rise in mumps lgG titer; or isolation of mumps virus from saliva, urine or cerebrospinal fluid. c. Epidemiologically-confirmed mumps : a patient with clinical mumps who is epidemiologically linked to a laboratory-confirmed mumps case. Summary: Mumps caused by an RNA virus of the family paramyxoviridae which has a predilection for glandular and nervous tissues. Clinically, the disease is recognized by non suppurative enlargement and tenderness of one or both the parotid glands. Other organs may also be involved. Questions: 1. A previously healthy 7-year-old child presented with acute, unilateral facial and neck swelling, associated with fever and malaise. She was not fully immunized. On examination fever 39.2 C, tender unilateral parotid swelling and unable to open mouth. A. What is the most likely diagnosis? B. What is the etiological agent? C. How can diagnose that disease? 2. A 27-year-old previously healthy man presented to the emergency department with a two-day history of fever and right-sided scrotal swelling. Records of his childhood vaccinations included immunization against measles–mumps–rubella (MMR) but did not specify the number of doses. The patient reported that he had a self-limited episode of bilateral painful neck swelling seven days before presenting to the emergency department. He did not have headache, neck stiffness, abdominal pain, urinary tract symptoms, urethral discharge or rash. Upon examination, his temperature was 39.0°C. The oropharynx was normal, and there was no swelling of the parotid glands. Testicular examination showed a tender right testis and epididymis. A. What is most likely cause in this case? B. What are other consequences of that disease? C. How can be prevented? THANK YOU