Measles, Mumps, Rubella Flashcards
A 7 year old boy presents to your clinic with a 10 day history cough, coryza and conjunctivitis. The family had recently travelled to California 2 weeks prior. The patient also developeda rash that started from the face and spread downwards to the toes centrally to peripheraly. Prior to the rash, the patient has lesions inside the oral cavity. What infection are you thinking?
For our purposes, we’re thinking measles
How do you diagnose Measles? (4 ways)
Serology (initial IgM levels then IgG afterwards)
Viral culture
RT-PCR
Pathology
Measles is highly infectious. Describe the transmission of the disease.
What are 4 classical symptoms of measles infection?
Which component of the immune system is implicated in measles infection?
Basically respiratory droplets (aka airborne)
**
Conjunctivitis, cough, coryza and Koplik spots in mouth before rash
**
Cellular immunity
___ is an enveloped, spherical single stranded RNA virus that causes measles
Measles virus (member of Paramyxovirus)
Name the 6 proteins that make up Measles virus
Hemagglutinin (attachment)
Fusion (entry)
Nucleocapsid
Polymerase and phosphoprotein
Non structural proteins: •regulate cellular response to infection (inhibit interferon)
Describe the pathophysiology of measles
(what is the incubation period for the virus before the onset of rash and/or fever?)
Invasion of respiratory epithelium >> lymph nodes >> blood stream (viremia - febrile illness ensues) >> dissemination to other organs
10 days to fever (pt is infectious at this point - viremia)
14 days to rash (indication of adaptive immune response and end of viremia)
Describe the effect of immune amnesia that happens with measles infection and how that relates to pt death
Immune amnesia: the virus infects immune cells and takes them out of circulation, which makes folks susceptible to other infections (so those are what lead to mortality)
**infections linked to mortality - pneumonia, diarrhea**
Name another complication that can arise from measles infection (hint: its in the brain)
Acute
Acute disseminated encephalomyelitis
Sub acute sclerosing panencephalitis - encephalitis that happens many years post infection
Which virus causes the condition below?
Measles virus
Name the diseases that make up the Paramyxovirus family
Measles
Mumps
Parainfluenza
The difference between mumps and measles pathogenesis is that after the virus infects the respiratory epithelium, spreads to lymph nodes and enters the blood stream, the virus disseminates to ___
The difference between mumps and measles pathogenesis is that after the virus infects the respiratory epithelium, spreads to lymph nodes and enters the blood stream, the virus disseminates to glandular sites
**think about sites that are close to the URT: salivary glands, cochlea, cardiac, seminiferous tubules, kidneys**
**Note also that its the immune response to infection that produced symptoms**
How is mumps transmitted?
During what time of year would you expect a pt with mumps to present?
Saliva, fomites but mainly respiratory transmission
Winter-spring
The glands most commonly affected by mumps include: __
Besides glandular infection, mumps can also cause what kind of meningitis?
The glands most commonly affected by mumps include: salivary glands and testes
**unilateral then usually spreads to other side**
**
Aseptic meningitis
What are 3 complications that can arise from mumps?
Encephalitis-meningitis
Deafness (rare, was common prior to infection): May occur with or without CNS disease
Infertility (rare even if bilateral orchitis): though epididymo-orchitis is common
What condition is illustrated below?
Mumps (note the angle of the jaw is gone; if you can see angle of the jaw: cervical lymphadenitis)
How is mumps diagnosed?
IgM antibody: 4-fold rise in IgG (wait for weeks after initial presentation)
Culture: Saliva, CSF
PCR: can be positive after vaccine
What virus causes a rash that starts all at once and disappears as quickly as it appears?
Rubella
(think about rubies. as soon as you see them you gon snatch them so naturally they don’t stick around for very long)
Rubella is a member of the __ virus family and is transmission thru __
Rubella is a member of the Togavirus family and is transmission thru person-person spread
Rubella is transmitted by ___ and has a 2-3 week incubation period. While people are often asymptomatic, clinical presentation includes rash, __ and __
Rubella is transmitted by large respiratory droplet and has a 2-3 week incubation period.
While people are often asymptomatic, clinical presentation includes rash, cervical lymphadenopathy and arthritis
Occipital and posterior auricular lymphadenopathy: remember the rubies in the back and behind the ear of the child king in the sketchy video
Which virus causes the condition illustrated below?
Rubella virus
What are the characteristics of congenital rubella syndrome (as in presentation)? (hint: organs affected - eyes, ears, heart)
Cataracts
Heart disease (patent ductus arteriosus, pulmonary artery stenosis)
Deafness
*note also hepatosplenomegaly and blueberry muffin rash - there’s other things that cause this rash btw)
Which virus is responsible for the “slapped cheeks” rash phenomenon?
Parvovirus B19
Describe the characteristics of Parvovirus B19
small, non enveloped, icosahedral capsid ss dna virus
How does parvovirus cause anemia? (think about where the virus infects for replication)
Parvovirus infects mitotically active cells for replication and such, so it likes erythroid precursors (and fetal capillary endothelium)
**note that it can also infect endothelial cells and myocardial cells but those aren’t related to the anemia**
Parvovirus is transmitted thru the ___ and by viremia, spreads to the bone marrow where it can cause anemia. Immune response to infection can then lead to __ and ___
Name 2 other ways by which parvovirus can be transmitted
Parvovirus is transmitted thru the respiratory tract and by viremia, spreads to the bone marrow where it can cause anemia. Immune response to infection can then lead to rash and arthralgias
Can also be transmitted by organ donation and blood transfusion
During what time of year would you expect parvovirus infection to occur?
Besides the slapped cheeck rash, what is a characteristic skin infection that is caused by parvovirus infection? (you can’t forget this one b/c you saw it in the clinic)
Infection peaks in late winter - early spring
Causes Fifth disease! (erythema infectiousum - high fever coincides with viremia then 5 days later: slapped cheek rash followed by lace-like reticular rash)
What is the primary manifestation of parvovirus in adult women?
Arthralgias, arthritis
**other one is aplastic anemia in people with hemoglobinopathies like sickle cell disease**
**others still: myocarditis, and non-immune hydrops fetalis - happens in pregaz**
How is parvovirus Dx?
Clinical findings
Serology (IgM/IgG)
PCR - blood, amniotic fluid, fetal cord blood
Explain how you would manage parvovirus infection in the following scenarios:
aplastic crisis
chronic infection in immunodeficient pts
exposed pregaz
Aplastic crisis: transfusion
Chronic infection in immunodeficient – IVIG
Exposed pregnant women - explain low risk and get ok for diagnostic testing. If infected fetus, follow w/ ultrasound and perform intrauterine transfusion
