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)
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)
Which virus causes the condition illustrated below?
Rubella virus
Which virus is responsible for the “slapped cheeks” rash phenomenon?
Parvovirus B19
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)
