measles Flashcards
what is measles?
highly contagious infection caused by morbillivirus of paramyxovirus family
what is measles caused by?
morbillivirus of the paramyxovirus family
what is the time scale of measles infection?
incubation period of 10 days with further 2-4 days of prodromal symptoms- malaise, fever, cough before characteristic skin rash develops
when is the person with measles infectious?
when symptoms first appear (4 days before rash appears) to 4 days after the onset of rash
how is measles spread?
airbone infection spread by droplets from coughing or sneezing, close personal contact or direct contact with nasal or throat secretions
why has the prevalence of measles dropped?
introduction of measles immunication
how often does complications of measles occur in developed countries?
10-20% but higher in developing countries
what are some of the infectious complications of measles and why do they occur?
measles virus suppresses reaction of the immune system to other pathogens
secondary infections of the respiratory tract include:
otitis media (7-9%)
pneumonitis
tracheobronchitis
pneumonia (1-6%)
what are some of the CNS complications?
convulsions (1 in 200 cases)
encephalitis (1 in 1000 cases)
blindness
subacute sclerosing panecehalitis (SSPE)
what is subacute sclerosing panecephalitis?
a rare but serious degenerative disease of CNS
involves seizures and decline in motor, cognitive and behavioural function
affects about 1 in 25,000 people with measles
up to 16 times more common in children who contract measles at very young age (less than 1 year)
occurs median of 7 years after exposure to virus
what is the prognosis of measles?
most make a full recovery with symptomatic management after 7 days of symptoms
death rare in developed countries
fatality depends on age of person, nutritional status, vaccine coverage and available healthcare
what to enquire about when you consider a diagnosis of measles in people presenting with a rash, fever etc?
check persons immunisation history
if person has had significant contact with possible case of measles
look for presence of typical features of measles
what are the typical features of measles?
presenting with classic symptoms of cough and coryzal symptoms and conjunctivitis and fever of 39 degrees or more without antipyretics and maculopapular rash
what are koplik’s spots?
pathognomonic for measles
may appear on buccal mucosa around same time as rash
consist of 2-3 mm red spots with white or blue-white centres
what is the typical rash in measles?
erythematous and maculopapular and may become confluent
appears on face and behind ears first when symptoms most severe
descends down body to trunk and limbs and forms on hands and feet last over course of about 3-4 days
rash fades after 5 days
