Common Viral Exanthemas (Measles, Chickenpox

1
Common Viral Exanthemas (Measles, Chickenpox
Rubella)

• Dr SARIKA GUPTA (MD,PhD),Assistant Professor

2
Measles-Etiology

• An acute viral disease
• Highly contagious
• Measles virus is a single-stranded,
  lipid-enveloped RNA virus in the family
  Paramyxoviridae and genus Morbillivirus
• Humans are the only host of measles virus
• Maintenance of gt90 immunity through vaccination-
  NO OUTBREAKS

3
(No Transcript)
4
Measles-Pathogenesis

• Necrosis of the respiratory tract epithelium an
  accompanying lymphocytic infiltrate
• Small vessel vasculitis on the skin on the oral
  mucous membranes
• Warthin-Finkeldey giant cells pathognomonic for
  measles, formed by fusion of infected cells, with
  up to 100 nuclei and intracytoplasmic and
  intranuclear inclusions
• Measles virus also infects CD4 T cells,
  resulting in suppression of the Th1 immune
  response

5
Measles-Pathogenesis

• 4 phases
• Incubation period
• Prodromal illness
• Exanthematous phase
• Recovery

6
Measles-Pathogenesis
7
Measles-Transmission

• Through the respiratory tract or conjunctivae
• Following contact with large droplets or
  small-droplet aerosols in which the virus is
  suspended
• Patients are infectious from 3-4 days before to
  up to 4-6 days after the onset of rash

8
Measles-Clinical Features

• High fever, an enanthem, cough, coryza,
  conjunctivitis a prominent exanthem
• Incubation period 8-12 days
• Prodromal phase mild fever, conjunctivitis with
  photophobia, coryza, a prominent cough KOPLIKS
  SPOTS
• Koplik spots enanthem the pathognomonic sign
  of measles
• Appear 1 to 4 days prior to the onset of the rash
• Discrete red lesions with bluish white spots in
  the center on the inner aspects of the cheeks at
  the level of the premolars

9
Measles-Clinical Features

• Koplicks spots spread
• to involve the lips,
• hard palate gingiva
• They also may occur
• in conjunctival folds

10
Measles-Clinical Features

• Temperature rises abruptly as rash appears may
  reach upto 40OC
• Measles rash generalized, maculopapular,
  erythematous, confluent
• The rash begins on the face around
• the hairline behind the ears
• It then spreads downward
• to the neck, trunk, arms, legs
• feet over next 24-48 hours

11
Measles-Clinical Features

• The rash fades over about 7 days in the same
  progression as it evolved
• Leaves a fine, browny, branny desquamation of
  skin
• Severity of disease related to the extent
  confluence of rash
• Rash may be absent in immunocompromised children
  
• Hemorrhagic measles (black measles) bleeding
  from mouth, nose or bowels

12
Measles-Clinical Features

• Diarrhoea more common in malnourished small
  children
• Severe cases generalized lymphadenopathy
  including cervical mesenteric lymph nodes
• Mild splenomegaly

13
Measles-Diagnosis

• Almost always based on clinical and epidemiologic
  findings (history of contact)
• Fever of at least 3 days with at least one of
  three C (cough, coryza, conjuctivitis)
• Decreased total white blood cell count, with
  relative lymphocytosis

14
Measles-Diagnosis

• IgM antibody in serum appears 1-2 days after the
  onset of the rash remains detectable for about
  1 mo
• Demonstration of a fourfold rise in IgG
  antibodies in acute convalescent specimens
  collected 2-4 wk later
• Viral isolation from blood, urine or respiratory
  secretions by culture or rt-PCR

15
Measles-Differential Diagnosis

• Rubella-rashes fever are less striking
• Roseola infantum (exanthem subitum)- rash appear
  as the fever disappears
• Echovirus
• Coxsachie
• Adenovirus
• Infectious mononucleosis
• Scarlet fever-diffuse fleshy papular rash with
  goose flesh texture

16
Measles-Differential Diagnosis

• Meningococcemia-rashes are similar but NO
  conjuctivitis cough
• Kawasaki disease- no cough, elevations of
  neutrophils and acute-phase reactants the
  characteristic thrombocytosis
• Drug fever

17
Measles-Complications

• Due to the pathogenic effects of the virus on the
  respiratory tract immune system
• Risk factors for complications
• Children lt5 years of age adults gt20 years of
  age
• Severe malnutrition
• Vitamin A deficiency
• Immunocompromised persons

18
Measles-Complications

• Pneumonia- giant cell pneumonia (direct viral
  infection) or superimposed bacterial infection
  (Streptococcus pneumoniae, Haemophilus influenzae
   Staphylococcus aureus)
• Croup, tracheitis or bronchiolitis
• Acute otitis media
• Sinusitis and mastoiditis
• Retropharyngeal abscess
• Activation of pulmonary tuberculoses

19
Measles-Complications

• Diarrhea vomiting
• Appendicitis- obstruction of the appendiceal
  lumen by lymphoid hyperplasia
• Febrile seizures
• Encephalitis- 1-3/1,000 cases of measles
  postinfectious, immunologically mediated process,
  not due to a direct viral effect

20
Measles-Complications

• Measles encephalitis in immunocompromised
  patients-from direct damage to the brain by the
  virus
• Thrombocytopenia
• Myocarditis
• Bacteremia, cellulitis toxic shock syndrome
• Measles during pregnancy-high maternal morbidity,
  fetal wastage stillbirths congenital
  malformations in 3 of live born infants

21
Measles-SSPE

• Fatal degenerative disease of central nervous
  system
• Chronic complication of measles
• Result from a persistent infection with an
  altered measles virus that is harbored
  intracellularly in the CNS for several years
• Usually after 7-10 year the virus apparently
  regains virulence attacks the cells in the CNS
• Change in personality, gradual onset of mental
  deterioration myoclonus
• Measles vaccination protects against SSPE

22
Measles-Treatment

• SUPPORTIVE
• Maintenance of hydration, oxygenation comfort
• Antipyretics-comfort and fever control
• Vitamin A supplementation-reduced morbidity and
  mortality from measles
• Single dose of 200,000 IU orally for children
  1 yr of age (100,000 IU for children 6 mo1 yr
  of age and 50,000 IU for infants lt6 mo of age)

23
Measles-Prevention

• Isolation- from 7 days after exposure to 4-6 days
  after the onset of rash
• Vaccine or immunoglobulin- vaccine is effective
  in prevention or modification of measles only if
  given within 72 hr of exposure. Immune globulin
  may be given up to 6 days after exposure to
  prevent or modify infection.
• Immune globulin-for susceptible household
  contacts younger than 6 months of age, pregnant
  women immunocompromised persons
• Immunization during an outbreak-immunize infant
  as young as 6 months of age additional dose at
  12-15 months of age

24
Rubella

• Rubella (German measles or 3-day measles)
• Mild exanthematous disease of infants children
• Major clinical significance- fetal damage as part
  of the congenital rubella syndrome
• Etiology Rubella virus RNA virus of genus
  Rubivirus under family Togaviridae
• Humans are the only known host

25
Rubella-Epidemiology

• Transmission-through oral droplet or
  transplacental route
• Virus is shed in nasopharyngeal secretions 7 days
  before exanthem upto 7-8 days after its
  disappearance
• Rubella susceptibility among women of child
  bearing age in India- 4-43

26
Rubella-Pathogenesis

• Infection virus replication in the
  respiratory epithelium spreads to regional
  lymph nodes
• viremia viral shedding from the
  nasopharynx
• Cellular tissue damage in the infected fetus
  tissue necrosis, reduced cellular multiplication
  time, chromosomal breaks production of a
  protein inhibitor causing mitotic arrests
• Most distinctive feature of congenital rubella
  chronicity
• Ongoing tissue damage and reactivation

27
Rubella

• Risk factor for severe congenital defects stage
  of gestation at the time of infection
• Maternal infection during the 1st 8 wk of
  gestation most severe widespread defects
• Risk for congenital defects 90 for maternal
  infection before 11 wk of gestation, 33 at
  11-12 wk, 11 at 13-14 wk 24 at 15-16 wk
• After 16 wk of gestation defects uncommon

28
Rubella-Clinical Features

• POSTNATAL INFECTION
• Incubation period 14-21 days
• Prodrome low-grade fever, sore throat, red eyes
  with or without eye pain, headache, malaise,
  anorexia lymphadenopathy (suboccipital,
  postauricular anterior cervical lymph nodes)
• Rash begins on the face neck as small,
  irregular pink macules that coalesce it spreads
  centrifugally to involve the torso extremities,
  where it tends to occur as discrete macules

29
Rubella-Clinical Features

• Rash fades from the face as it extends to the
  rest of the body so that the whole body may not
  be involved at any 1 time
• The duration of the rash is generally 3 days it
  resolves without desquamation

30
Rubella-Clinical Features

• About the time of onset of the rash, examination
  of the oropharynx- reveal tiny, rose-colored
  lesions (Forchheimer spots) or petechial
  hemorrhages on the soft palate
• Subclinical infections are common (25-40)
• Polyarthritis or arthralgia-common in adult
  females
• Lab findings Leukopenia, neutropenia mild
  thrombocytopenia

31
Rubella-Differential Diagnosis

• Mild form of measles
• Scarlet fever
• Roseola infantum
• Enteroviral infections
• Drug fever
• Infectoius mononucleosis
• Erythema infectiosum

32
Rubella-Diagnosis

• Supportive history of exposure or consistent
  clinical findings
• Rubella specific IgM enzyme immunosorbent assay
  (4-72 days)
• Fourfold rise in IgG in sequential sera
• Rubella virus culture from nasopharynx blood by
  tissue culture system or PCR
• WHO definition of PROBABLE infection fever,
  maculopapular rash, lymphadenopathy or
  arthralgia/arthritis
• WHO definition of CONFORMED infection probable
  case with IgM positivity within 28 days of onset
  of rash

33
Rubella-Complications

• Postinfectious thrombocytopenia 
• Arthritis- classically involves the small joints
  of the hands
• Encephalitis-a postinfectious syndrome following
  acute rubella a rare progressive
  panencephalitis manifesting as a
  neurodegenerative disorder years following
  rubella
• Guillain-Barré syndrome, peripheral neuritis
• Myocarditis

34
Congenital Rubella Syndrome

• Result of in utero fetal infection
• Classical CRS triad cataract, sensorineural
  hearing loss congenital heart disease
• Clinical manifestations
• Intrauterine growth restriction, postnatal mental
  motor retardation
• Bilateral/unilateral cataract, salt-and-pepper
  retinopathy, microphthalmia
• Nerve deafness
• Meningoencephalitis at birth

35
Congenital Rubella Syndrome

• Patent ductus arteriosus, pulmonary artery
  stenosis, VSD ASD, myocarditis
• Hepatitis
• Dermal erythropoiesis (blueberry muffin lesions)
• Thrombocytopenic purpura
• Anemia
• Hepatosplenomegaly
• Microcephaly
• Interstitial pneumonitis
• Delayed manifestations Diabetes mellitus (20),
  thyroid dysfunction (5)

36
Rubella-Treatment

• No specific treatment available for either
  acquired rubella or CRS
• Supportive treatment- antipyretics and analgesics
• Intravenous immunoglobulin or corticosteroids-for
  severe, nonremitting thrombocytopenia
• Hearing screening- important, early intervention
  improve outcomes

37
Rubella-Treatment

• Management of exposed pregnant women
• Rubella antibody status is tested immediately
  result positive mother is immune no
  further action
• Rubella antibody status negative repeat
  samples after 1-2 weeks negative 1st
  specimen positive test result in either the 2nd
  or 3rd specimen seroconversion suggesting
  recent infection termination of pregnancy
  

38
Rubella-Treatment

• Management of congenital rubella syndrome
• Children with CRS may excrete the virus in
  respiratory secretions up to 1 yr of age
• Isolation contact precautions maintained unless
  repeated cultures of urine and pharyngeal
  secretions have negative results
• Isolation at home my be required for 1 year
• Care of CRS infants require multidisciplinary
  team
• Prognosis poor
• PREVENTION by IMMUNIZATION

39
Chickenpox (Varicella)

• Varicella is an acute febrile rash illness
• Caused by VZV which is a neurotropic human a-
  herpesvirus
• Secondary attack rate 90
• Transmission by airborne spread or through
  direct contact with skin lesions
• Varicella results from inoculation of the virus
  onto the mucosa of the upper respiratory tract
  tonsillar lymphoid tissue

40
Chickenpox-Pathogenesis
41
Chickenpox (Varicella)

• Transportation of virus in a retrograde manner
  through sensory axons to the dorsal root ganglia
  throughout the spinal cord
  establishment of virus latent infection in the
  neurons subsequent reactivation 
  
• herpes zoster, a vesicular rash
  that usually is dermatomal in distribution

42
Chickenpox-Clinical Fetures

• Prodromal symptoms fever (moderate), malaise,
  anorexia, headache occasionally mild abdominal
  pain, 24-48 hours before the rash appears
• These symptoms resolve within 2-4 days after the
  onset of the rash
• Varicella rash often appear first on the scalp,
  face, or trunk
• The initial exanthem consists of intensely
  pruritic erythematous macules that evolve through
  the papular stage to form clear, fluid-filled
  vesicles
• Clouding umbilication of the lesions begin in
  24-48 hr

43
Chickenpox-Clinical Fetures

• While the initial lesions are crusting, new crops
  form on the trunk then the extremities
• The simultaneous presence of lesions in various
  stages of evolution is characteristic of
  varicella
• The distribution of the rash is predominantly
  central or centripetal

Pearl on a rose patel
44
Chickenpox-Clinical Fetures

• The average number of varicella lesions is about
  300 (10-1500)
• Hypopigmentation or hyperpigmentation of lesion
  sites persists for days to weeks in some children
• Severe scarring is unusual unless the lesions
  were secondarily infected

45
Chickenpox-Differential Diagnosis

• Vesicular rashes caused by
• Herpes simplex virus
• Enterovirus
• Rickettsial pox
• S. aureus
• Drug reactions
• Contact dermatitis
• Insect bites

46
Chickenpox-Diagnosis

• CLINICAL
• Leukopenia during the 1st 72 hours after onset of
  rash followed by a relative absolute
  lymphocytosis
• Elevated hepatic enzymes
• Specific diagnosis of VZV infection needed in
  immunocompromised children

47
Chickenpox-Complictions

• Mild thrombocytopenia, petechiae (common)
  purpura, hemorrhagic vesicles, hematuria
  gastrointestinal bleeding (rare)
• Cerebellar ataxia, encephalitis, Guillian-Barre
  syndrome, transverse myelitis
• Pneumonia
• Nephritis, nephrotic syndrome, hemolytic-uremic
  syndrome
• Arthritis
• Myocarditis, pericarditis
• Pancreatitis

48
Chickenpox-Complictions

• Orchitis
• Secondary bacterial infections of the skin (group
  A streptococci  S. aureus) impetigo,
  cellulitis, lymphadenitis subcutaneous
  abscesses varicella gangrenosa- more invasive
  skin infections

49
Congenital Varicella Syndrome

• In infants born to women who have varicella
  before 20 wk of gestation
• Characterized by
• Cicatricial skin scarring in a zoster-like
  distribution, limb hypoplasia
• Neurologic abnormalities microcephaly, cortical
  atrophy, seizures mental retardation
• Eye abnormalities chorioretinitis,
  microphthalmia cataracts
• Renal abnormalities hydroureter hydronephrosis
• Autonomic nervous system abnormalities
  neurogenic bladder, swallowing dysfunction
  aspiration pneumonia

50
Chickenpox-Complictions

• If a baby is born lt4 days after onset of maternal
  varicella or upto 2 days before the onset high
  risk for severe varicella a high mortality rate

51
Chickenpox-Treatment

• Supportive treatment for fever itching
• Indications for acyclovir in children
• Malignancies
• BMT
• Chmotherapy or high dose steroid treatment
• HIV infection
• Severe vaicella
• Chronic skin disease
• Long term salicylate therapy
• Chlidren gt12 years
• Treatment should be initiated within 24 hr of
  the onset of rash

52
Chickenpox-Treatment

• Foscarnet is the only drug for the treatment of
  acyclovir-resistant VZV infections (in children
  infected with HIV)

53
Chickenpox-Prevention

• Since persons with chickenpox are infectious for
  1-2 days before the onset of rash isolation only
  reduces the spread
• Individual protection NECESSARY (vaccine)