Overview
Definition:
Measles is a highly contagious viral illness caused by the measles virus (a paramyxovirus), characterized by fever, cough, coryza, conjunctivitis, and a characteristic maculopapular rash
It is a significant cause of morbidity and mortality in unvaccinated children worldwide.
Epidemiology:
Measles is endemic in many parts of the world, particularly in regions with low vaccination coverage
Outbreaks can occur rapidly due to the virus's high transmissibility
In India, measles remains a public health concern despite vaccination efforts, with outbreaks frequently reported
The disease primarily affects unvaccinated children, with peak incidence in those aged 6-12 months and 1-5 years
The introduction of measles vaccine has drastically reduced its incidence in developed countries, but it remains a major challenge in developing nations.
Clinical Significance:
Measles is important for pediatricians and residents preparing for DNB and NEET SS exams due to its potential for severe complications and its role as an indicator of public health vaccination status
Prompt recognition, appropriate isolation measures, and timely vitamin A supplementation are crucial for reducing morbidity, mortality, and secondary spread.
Clinical Presentation
Symptoms:
Prodromal phase (2-4 days): Fever, often high
Cough, persistent and dry
Coryza, clear nasal discharge
Conjunctivitis, bilateral, with photophobia
Koplik spots, small white or bluish-white spots on the buccal mucosa, typically appearing 1-2 days before the rash
Rash phase (3-5 days after onset of symptoms): Maculopapular rash, starting on the face and behind the ears, spreading downwards to the trunk and limbs
The rash may coalesce
Resolution of fever and rash often occurs around the same time.
Signs:
Fever (may be as high as 40°C)
Conjunctival injection
Nasal discharge
Pharyngeal erythema
Characteristic Koplik spots on buccal mucosa
Generalized maculopapular rash, blanching initially, then becoming purpuric
Cervical lymphadenopathy may be present
Possible mild hyaline cough.
Diagnostic Criteria:
Clinical diagnosis is based on characteristic symptoms and signs, especially the presence of fever, cough, coryza, conjunctivitis, and the pathognomonic Koplik spots, followed by a descending maculopapular rash
Laboratory confirmation is recommended for public health surveillance and outbreak investigation
This includes detection of measles-specific IgM antibodies in serum collected during or after rash onset, or detection of measles RNA by RT-PCR in throat, nasopharyngeal, or urine samples
A four-fold rise in measles-specific IgG antibody titers between acute and convalescent serum samples can also confirm infection.
Diagnostic Approach
History Taking:
Detailed history of fever onset and duration
Character of cough, coryza, and conjunctivitis
Presence of photophobia
History of vaccination status (including number of doses and timing)
Exposure to known measles cases
Travel history
Any recent immunosuppression or underlying medical conditions
Red flags include high fever, severe cough, signs of respiratory distress, neurological symptoms, or immunocompromised state.
Physical Examination:
General examination: assess hydration, nutritional status, and signs of distress
Vital signs: temperature, heart rate, respiratory rate
HEENT: examine conjunctivae for injection, observe for nasal discharge, check buccal mucosa for Koplik spots
Respiratory system: auscultate for rales, rhonchi, or signs of pneumonia
Skin: observe the distribution and character of the rash.
Investigations:
Serological tests: Measles IgM antibody assay (positive from day 3-4 of rash onset, remains positive for several weeks)
Measles IgG antibody assay (useful for assessing past infection or immunity, acute and convalescent titers for diagnosis)
Molecular tests: RT-PCR for measles RNA from throat swab, nasopharyngeal aspirate, or urine (detects virus early in infection, useful for outbreak investigation)
Complete blood count (CBC) may show lymphocytosis or leukopenia
it is not diagnostic but can rule out secondary bacterial infection.
Differential Diagnosis:
Other viral exanthems: rubella, roseola infantum, erythema infectiosum (fifth disease), enteroviruses
Bacterial infections: scarlet fever
Drug reactions
Kawasaki disease
Pityriasis rosea.
Management
Initial Management:
Isolation: immediate airborne isolation (negative pressure room or cohorting with other measles patients) to prevent transmission is paramount
This should be maintained for at least 4 days after the onset of rash
Supportive care: focus on hydration, nutrition, and symptomatic relief.
Medical Management:
Vitamin A supplementation: Crucial for reducing measles-related morbidity and mortality, especially in malnourished children or those with severe measles
WHO recommends vitamin A (200,000 IU orally for children >1 year, 100,000 IU for infants 6-11 months) on diagnosis and repeated the next day
A third dose can be given 2-4 weeks later
Dosing should be adjusted based on age and nutritional status
For children with clinical signs of vitamin A deficiency, higher doses may be indicated
Antipyretics: Acetaminophen or ibuprofen for fever
Antitussives may be considered for bothersome cough
Antibiotics are NOT indicated for uncomplicated measles but are crucial for treating secondary bacterial complications (e.g., otitis media, pneumonia).
Surgical Management:
Not applicable for uncomplicated measles
Surgical interventions may be required for managing complications like lung abscesses or complications of encephalitis, but this is rare.
Supportive Care:
Maintain adequate hydration through oral fluids or intravenous fluids if necessary
Ensure good nutrition
Monitor vital signs closely for any deterioration
Eye care: warm compresses for conjunctivitis
Nasal care: saline drops and suction for nasal congestion
Strict adherence to airborne precautions for all healthcare personnel and visitors.
Complications
Early Complications:
Otitis media (most common bacterial complication)
Pneumonia (viral or secondary bacterial)
Laryngotracheobronchitis
Diarrhea
Keratoconjunctivitis leading to corneal ulceration and blindness (especially with vitamin A deficiency)
Stomatitis
Encephalitis (1 in 1000 cases, often severe and can lead to permanent neurological sequelae)
Myocarditis
Thrombocytopenia.
Late Complications:
Subacute sclerosing panencephalitis (SSPE): a rare, fatal neurodegenerative disease that can occur years after measles infection, particularly in those infected at a young age.
Prevention Strategies:
High vaccination coverage with at least two doses of measles-containing vaccine (MCV) is the most effective strategy
Post-exposure prophylaxis with measles immunoglobulin (IG) within 6 days of exposure can modify or prevent measles in susceptible individuals
Prompt isolation of infected individuals to prevent further spread
Health education on hygiene and infection control measures.
Prognosis
Factors Affecting Prognosis:
Age (infants and adults have worse prognosis)
Nutritional status (malnutrition significantly increases mortality)
Immune status (immunocompromised individuals have higher risk of complications and mortality)
Presence and severity of complications
Access to medical care and timely treatment.
Outcomes:
In well-nourished children with access to care and vitamin A supplementation, the prognosis for uncomplicated measles is generally good, with complete recovery
However, severe complications can lead to long-term disability or death
Mortality rates are significantly higher in developing countries and in immunocompromised individuals.
Follow Up:
Children who have had measles should be monitored for signs of complications, especially pneumonia, otitis media, and neurological issues
If vitamin A deficiency was suspected or present, follow-up for signs of visual impairment is important
Regular well-child check-ups should include assessment of growth and development
For SSPE, long-term neurological monitoring is required.
Key Points
Exam Focus:
Airborne isolation for 4 days post-rash
Vitamin A is crucial to reduce mortality (dosing is key: 200k IU >1yr, 100k IU 6-11mo)
Koplik spots are pathognomonic prodromal sign
Measles encephalitis is immune-mediated or direct viral invasion
SSPE is a late complication
Vaccination is primary prevention.
Clinical Pearls:
Always ask about vaccination status in children presenting with fever and rash
Remember Koplik spots are transient
look for them early
Aggressive supportive care and timely identification of secondary bacterial infections are critical
Consider vitamin A deficiency in malnourished populations.
Common Mistakes:
Delayed isolation leading to nosocomial outbreaks
Underestimating the severity of measles and its complications
Inadequate or delayed vitamin A supplementation
Failing to consider secondary bacterial infections and treat them promptly
Misdiagnosing measles as less severe viral exanthems.