This document discusses measles, an acute viral infection characterized by a maculopapular rash. It covers the etiology (measles virus), epidemiology (endemic worldwide, high transmission rate), clinical features (incubation 10-12 days, prodrome of fever and cough, pathognomonic Koplik's spots, spreading rash), diagnosis (clinical features, IgM antibodies, virus isolation), and differentiation from other rash-causing illnesses. Measles is highly contagious and can cause severe illness or death, especially in malnourished or unvaccinated children.
2. Measles
• It is an acute viral infection characterized by a final stage
with a maculopapular rash erupting successively over the
neck and face, trunk, arms, and legs, and accompanied
by a high fever and catarrhal symptoms of URT.
3.
4. Etiology
• Measles virus, the cause of measles, is an RNA virus of the
genus Morbillivirus in the family Paramyxoviridae.
• Only one serotype is known
• It is rarely subclinical .
5. Epidemiology
• Measles is endemic throughout the world.
• In the past, epidemics tended to occur irregularly , appearing in
the spring in large cities at 2-4-yr intervals (3 yr interval in India)
as new groups of susceptible children were exposed
• When introduced into a virgin community more than 90% of that
community will be infected.
6. • Prior to the use of measles vaccine, the peak incidence was
among children 5-10 yr of age.
• Disease has high mortality and morbidity in developing
countries
8. Epidemiological determinants
• Agent factors
AGENT : paramyxo virus
Cannot survive outside human body
SOURCE OF INFECTION : A case of measles
carriers are not known to occur
subclinical measles occur more often.
INFECTIVE MATERIAL : Secretion of the nose, throat and respiratory
tract of a case of measles.
9. COMMUNICABILITY : Highly infectious during prodomal period and
eruption
declines rapidly after appearance of rash.
SECOND ATTACK RATE : There is only one antigenic type of measles
virus
infection confers lifelong immunity
10. • Host factors
AGE : Infancy or childhood (6 months to 3 years of age)
SEX : Incidence equal
IMMUNITY : No inborn immunity. Immunity conferred only by attack of
measles
11. NUTRITION : Tends to be severe in the malnourished Children
Carrying a mortality upto 400 times higher than in well nourished children having
measles.
May be related to poor cell meditated immune response secondary to malnutrition
Additionally severely malnourished have been shown to excrete measles virus for
longer periods.
An attack of severe measles may be followed by weight loss precipitating the
child into malnutrition.
12. Transmission
• Measles is highly contagious ; directly from person to person
• Maximal dissemination of virus occurs by droplet infection and
droplet nuclei during the prodromal period ( catarrhal stage ).
13. • Transmission to susceptible contacts often occurs prior to
diagnosis of the index case
• Portal of entry is respiratory tract
• Infection through conjunctiva is considered likely
• Recipients of vaccine are non-contagious to others
14. Pathogenesis
• The essential lesion of measles is found in the skin ,
conjunctivae , and the mucous membranes of the nasopharynx
, bronchi , and intestinal tract .
• Serous exudate and proliferation of mononuclear cells and a
few polymorphonuclear cells occur around the capillaries
15. • Hyperplasia of lymphoid tissue usually occurs, particularly in
the appendix, where multinucleated giant cells of up to 100
μm in diameter ( Warthin-Finkeldey reticuloendothelial giant
cells ) may be found.
• In the skin , the reaction is particularly notable about the
sebaceous glands and hair follicles
16. • Koplik spots consist of serous exudate and proliferation of
endothelial cells similar to those in the skin lesions.
• A general inflammatory reaction of the buccal and pharyngeal
mucosa extends into the lymphoid tissue and the
tracheobronchial mucous membrane
17. • Interstitial pneumonitis resulting from measles virus takes the
form of Hecht giant cell pneumonia .
• Bronchopneumonia may occur from secondary bacterial
infection
19. Incubation period
• lasts approximately 10-12 days to the first prodromal symptoms
and another 2-4 days to the appearance of the rash; rarely, it
may be as short as 6-10 days .
• Body temperature may increase slightly 9-10 days from the date
of infection and then subside for 24 hr or so.
• The patient may transmit the virus by the 9th-10th day after
exposure and occasionally as early as the 7th day, before the
illness can be diagnosed
20. Predomal phase
• usually lasts 3-5 days and is characterized by:
• low-grade to moderate fever
• dry cough
• coryza
• conjunctivitis .
These symptoms nearly always precede the appearance of Koplik spots
, the pathognomonic sign of measles, by 2-3 days
21. • The conjunctival inflammation and photophobia may suggest
measles before Koplik spots appear.
• .
22. Koplicks spot
• An enanthem or red mottling is usually present on the hard and soft
palates
• the pathognomonic sign of measles
• are grayish white dots , usually as small as grains of sand, that have slight,
reddish areolae ; occasionally they are hemorrhagic .
• tend to occur opposite the lower molars but may spread irregularly over
the rest of the buccal mucosa.
• Rarely they are found within the midportion of the lower lip , on the palate ,
and on the lacrimal caruncle .
• They appear and disappear rapidly , usually within 12-18 hr .
• As they fade , a red , spotty discoloration of the mucosa may remain
23.
24. Predomal phase (cont.)
• Occasionally , the prodromal phase may be severe , being
ushered in by a sudden high fever , sometimes with convulsions
and even pneumonia .
• Usually the coryza, fever, and cough are increasingly severe up
to the time the rash has covered the body.
• The temperature rises abruptly as the rash appears and often
reaches 40°C (104°F) or higher.
25. • In uncomplicated cases , as the rash appears on the legs and
feet, the symptoms subside rapidly within about 2 days , usually
with an abrupt drop in temperature to normal.
26. Eruptive stage
Usually starts as faint macules on the:
upper lateral parts of the neck
behind the ears
along the hairline
posterior parts of the cheek .
27. The rash
The individual lesions become increasingly maculopapular as the
rash spreads rapidly over the:
• entire face
• neck
• upper arms
• upper part of the chest
within approximately the first 24 hr <
28.
29. • During the succeeding 24 hr the rash spreads over the back,
abdomen, entire arm, and thighs.
• As it finally reaches the feet on the 2nd-3rd day , it begins to
fade on the face.
30. • The rash fades downward in the same sequence in which it
appeared.
• The severity of the disease is directly related to the extent and
confluence of the rash.
• In mild measles the rash tends not to be confluent , and in very
mild cases there are few, if any, lesions on the legs
31. • In severe cases the rash is confluent , the skin is completely
covered, including the palms and soles, and the face is swollen
and disfigured.
• The rash is often slightly hemorrhagic ; in severe cases with a
confluent rash, petechiae may be present in large numbers, and
there may be extensive ecchymoses
32. • Complete absence of rash is rare except :
• 1. in patients who have received immunoglobulin (Ig) during the
incubation period
• 2. in some patients with HIV infection
• 3. occasionally in infants younger than 9 mo of age who have
appreciable levels of maternal antibody
33. • In the hemorrhagic type of measles ( black measles ), bleeding
may occur from the mouth, nose, or bowel.
• In mild cases the rash may be less macular and more nearly
pinpoint , somewhat resembling that of scarlet fever or rubella
34. • Itching is generally slight .
• As the rash fades , branny desquamation and brownish
discoloration occur and then disappear within 7-10 days.
35. Diagnosis
• The diagnosis is usually apparent from the characteristic
clinical picture ; laboratory confirmation is rarely needed
• Testing for measles IgM antibodies is recommended in
some situations
• Measles IgM is detectable for 1 mo after illness , but
sensitivity of IgM assays may be limited in the first 72 hr of
the rash illness.
36. • Isolation of measles virus from clinical samples is also
useful in identifying the genotype of the strain to track
transmission patterns.
• All suspected measles cases should be reported
immediately to local or health departments.
• During the prodromal stage multinucleated giant cells can
be demonstrated in smears of the nasal mucosa
37. • Antibodies become detectable when the rash appears ;
• Testing of acute and convalescent sera demonstrates the
diagnostic seroconversion or fourfold increase in titer.
• Measles virus can be isolated by tissue culture in human
embryonic or rhesus monkey kidney cells
38. • Cytopathic changes , visible in 5-10 days, consist of
multinucleated giant cells with intranuclear inclusions .
• The white blood cell count tends to be low with a relative
lymphocytosis
• Cerebrospinal fluid in patients with measles encephalitis
usually shows an increase in protein and a small increase in
lymphocytes . The glucose level is normal.
39. • The rash of rubeola must be differentiated from that of:
• Rubella
• Roseola infantum (human herpesvirus 6
• Infections resulting from:
• echovirus
• coxsackievirus
• adenovirus
• Infectious mononucleosis
• Toxoplasmosis
• Meningococcemia
• Scarlet fever
• Rickettsial diseases
• Kawasaki disease
• Serum sickness
• Drug rashes