Measles, Mumps and Rubella Flashcards
[6-minute video]: Measles - Professor Dave Explains
[6-minute video]: Mumps - Osmosis from Elsevier
[7-minute video]: Rubella - Animated Biology with Arpan
🛸
Briefly discuss the structure and genome of Paramyxoviruses.
🛸 enveloped, spherical or pleomorphic
🛸 non-segmented negative-sense RNA
[Diagram]
Paramyxovirus, which causes measles, is classified under the genus ____________.
Morbillivirus
Discuss the pathogenesis of measles.
🛸 The measles virus enters the body through the respiratory tract. It attaches to host cells using the hemagglutinin (H) protein, which binds to receptors like CD150 (Signalling Lymphocytic Activation Molecule: SLAM) on immune cells.
🛸 The fusion (F) protein facilitates the fusion of the viral envelope with the host cell membrane, allowing the viral RNA to enter the host cell.
🛸 Inside the host cell, the viral RNA-dependent RNA polymerase transcribes the negative-sense RNA genome into positive-sense mRNA, which is then translated into viral proteins.
🛸 The virus initially replicates in the alveolar macrophages and dendritic cells and then spreads to local lymphoid tissues.
🛸 The virus then disseminates through the bloodstream to various organs, including the skin, liver and spleen.
[Diagram] [Diagram 2] [Diagram 3]
Outline signs and symptoms of measles.
fever, dry cough, runny nose, sore throat, conjunctivitis, Koplik’s spots, maculopapular rash
[Diagram 1] [Diagram 2] [Image 1] [Image 2]
Koplik spots: [Image 3] [Image 4]
Further notes:
🛸 A maculopapular rash is characterized by both flat and raised skin lesions. Features:
(a) Macules: flat, discolored spots on the skin
(b) Papules: small, raised bumps
🛸 [Short video]: Measles vs Chickenpox
What complications may be associated with Measles infection?
(1) Bronchopneumonia: It is the most common cause of death from measles in young children. [It affects about 1 in 20 children with measles.]
(2) Otitis media: An ear infection that can lead to hearing loss if not treated properly. [It occurs in about 1 in 10 children with measles.]
(3) Laryngotracheobronchitis: Inflammation of the larynx, trachea, and bronchi, causing barking cough and difficulty breathing.
(4) Diarrhea
(5) Blindness: Can result from severe measles infection, particularly in malnourished children or those with vitamin A deficiency.
(6) Encephalitis: This includes:
✔ Acute Meningoencephalitis (AME): Inflammation of the brain and its surrounding membranes, leading to severe neurological symptoms.
✔ Subacute Sclerosing Panencephalitis (SSPE): A rare, fatal brain disorder that occurs years after the initial measles infection.
Further notes:
Subacute Sclerosing Panencephalitis (SSPE) is a devastating and rare neurological disorder that typically develops 7 to 10 years after a person has recovered from measles.
Pathogenesis:
Cause: SSPE is caused by a persistent infection with a mutated form of the measles virus that remains in the brain.
Mechanism: The virus slowly damages the central nervous system, leading to progressive neurological deterioration.
Symptoms:
Early Symptoms: Behavioral changes, memory loss, and intellectual decline.
Progression: As the disease advances, symptoms include muscle spasms, seizures, and loss of motor skills.
Late Stages: Severe neurological impairment, leading to coma and eventually death.
Prognosis:
Outcome: SSPE is almost always fatal, with most patients dying within 1 to 3 years of diagnosis.
Treatment: There is no cure, but antiviral medications and supportive care can help manage symptoms and potentially slow progression.
Briefly discuss diagnostic tests for Measles.
(1) Serology
🦠 IgM antibodies: Detection of measles-specific IgM antibodies in the blood is a primary method for diagnosing acute measles infection. These antibodies typically appear within a few days of rash onset and can be detected for up to a month.
🦠 Paired IgG: Measuring IgG antibodies in paired serum samples taken during the acute and convalescent phases can show a four-fold increase, confirming recent infection.
(2) PCR testing of throat, nasopharynx, blood or urine samples
(3) Lymph Node Biopsy: Examination of a lymph node biopsy can reveal multinucleated giant cells, known as Warthin-Finkeldey cells, with paracortical hyperplasia. These findings are characteristic of measles infection and can support the diagnosis, especially in complicated cases. [Slide 1] [Slide 2] [Slide 3] [Slide 4]
Briefly discuss treatment of Measles.
✔ treatment is supportive
✔ no specific antiviral medications have been licensed for the treatment of measles
Briefly discuss prevention of Measles.
💉 Administration of MMR (Measles/Mumps/Rubella) vaccine which contains live attenuated viruses.
Name three types of Measles-containing vaccines.
(a) Measles & Rubella vaccine (MR) [given in Kenya at 9 and 18 months]
(b) Measle, Mumps & Rubella vaccine (MMR)
(c) Measles, Mumps, Rubella and Varicella Vaccine (MMRV)
Further notes:
Measles-only is currently not available.
Which vitamin has been used in the treatment of measles?
Vitamin A
Mumps virus
(a) Family
(b) Basic structure
(c) Genome type
Mumps transmission
🩺 Respiratory droplets
🩺 Direct contact with saliva of infected persons e.g through sharing utensils
🩺 Touching surfaces or objects contaminated with the virus and then touching the mouth or nose [contact with fomites].
Further notes:
It most commonly affects children between the ages of 5 and 9.
Mumps clinical presentation
What are the complications of Mumps?
(1) Orchitis: Unilateral (mostly)/bilateral testicular inflammation, testicular pain and swelling, permanent or temporary hypofertility development, fever
(2) Acute pancreatitis: Severe epigastric pain radiating to the back, increased serum amylase/lipase, enlarged pancreas with peripancreatic fluid on imaging
(3) Neurological disease: Aseptic meningitis, encephalitis, sensorineural hearing loss
(4) Deafness
Briefly discuss specimen collection and diagnosis of mumps.
◾ Specimen: saliva, urine, CSF, blood
◾ PCR to detect viral RNA
◾ Serology to detect anti-Mumps IgM antibodies
Management of Mumps
◾ No specific treatment is available
◾ MMR vaccine (live attenuated)
Rubella virus
(a) Family
(b) Genus
(c) Basic structure
(d) Genome
Rubella transmission
respiratory droplets, direct contact (saliva, fomites), congenital transmission (transplacentally)
Briefly discuss the pathogenesis of postnatal Rubella.
🛸 The virus typically enters the body through the respiratory epithelium of the nasopharynx.
🛸 After entry, the virus replicates in the epithelial cells of the respiratory tract.
🛸 The virus then spreads to regional lymph nodes (primary viremia) and replicates in the reticuloendothelial system.
🛸 Approximately 6-20 days after infection, the virus spreads via the bloodstream to various body sites, including skin, joints and other organs (secondary viremia).
Rubella clinical presentation
(1) Non-specific signs: Fever, anorexia, headache
(2) Pharyngitis
(3) Conjunctivitis
(4) Tender lymphadenopathy (sub-occipital)
(5) Forchheimer sign (20% of patients): Pin point lesions or petechiae in the soft palate [Image]
(6) Rash: Maculopapular
What are some complications of postnatal Rubella in:
(a) younger children
(b) adolescents and adults
(a) younger children: encephalitis
(b) adolescents and adults: arthralgia/arthritis, thrombocytopenic purpura
Outline symptoms of Congenital Rubella Syndrome.
🩺 Sensorineural hearing loss (in 60% of patients)
🩺 Ocular abnormalities (40%) – cataracts, glaucoma, retinopathy
🩺 Cardiac abnormalities (50%) – PDA, PA stenosis
🩺 Abortion/stillbirth
🩺 CNS: mental retardation, hypotonia, microcephaly, encephalitis
🩺 Hepatosplenomegaly
🩺 Anemia & thrombocytopenic purpura
Further notes:
◾ thrombocytopenic purpura: Thrombocytopenic purpura is a condition characterized by a low platelet count (thrombocytopenia) and the presence of purpura, which are purple spots on the skin caused by bleeding underneath.
◾ PDA (Patent Ductus Arteriosus) is a condition where the ductus arteriosus, a blood vessel that allows blood to bypass the lungs in a fetus, fails to close after birth. This results in abnormal blood flow between the aorta and the pulmonary artery.
◾ PA stenosis is a condition characterized by the narrowing of the pulmonary artery.
◾ A mnemonic for some of the symptoms:
Rubi’s: Congenital rubella
Cat: cataracts
Has: heart defects
Deafness: sensorineural deafness
Identify: [Image]
Warthin-Finkeldy cell
Which one of the following statements about Sub-acute Sclerosing Panencephalitis is false?
(a) It has a gradual onset
(b) It is caused by measles virus
(c) It is rare
(d) It can occur more than 5 years after the initial measles attack
(e) It is usually resolves without any antiviral therapy
(e) It is usually resolves without any antiviral therapy
The following is true about Measles virus except?
(a) It has a HN (hemagglutinin & neuraminidase) surface glycoprotein
(b) It is enveloped
(c) Has a Fusion (F) glycoprotein
(d) Man is the only reservoir
(e) Highly contagious
(a) It has a HN (hemagglutinin & neuraminidase) surface glycoprotein
