Measles

Essentials of Diagnosis

• Onset of prodrome 7–18 days after exposure in an unvaccinated patient

• Prodrome:

  • Fever

  • Coryza

  • Cough

  • Conjunctivitis

  • Malaise

  • Irritability

  • Photophobia

  • Koplik spots

• Rash

  • Brick red, irregular, maculopapular

  • Appears 3–4 days after onset of prodrome

  • Begins on the face and proceeds "downward and outward," affecting the palms and soles last

• Leukopenia

General Considerations

• Transmitted by inhalation of infective droplets

• Highly contagious

• Communicability is greatest during the preeruptive and catarrhal stages, continuing for 4 days after the appearance of rash

• Illness confers permanent immunity

Demographics

• Between January 1 and October 1, 2019, a total of 1249 measles cases and 22 measles outbreaks were reported in 31 states of the United States

• The WHO previously considered measles eradicated in most countries worldwide including the Americas

• However, many countries now have ongoing measles outbreaks, including

  • The Democratic Republic of the Congo

  • Ethiopia

  • Georgia

  • Kazakhstan

  • Kyrgyzstan

  • Madagascar

  • Myanmar

  • Philippines

  • Sudan

  • Thailand

  • Ukraine

• During 2019, measles outbreaks have also occurred in countries with high vaccination coverage, including

  • The United States

  • Israel

  • Thailand

  • Tunisia

  • Many European countries

• Intentional undervaccination continues to undermine measles elimination programs

Symptoms and Signs

• Prodromal phase

  • Fever

  • Malaise may be marked

  • Coryza (nasal obstruction, sneezing, and sore throat)

  • Persistent and nonproductive cough

  • Conjunctivitis manifests as redness, swelling, photophobia, and discharge

• These symptoms intensify over 2–4 days before onset of the rash and peak on the first day of the rash

• Characteristic measles rash appears on the face and behind the ears

  • Initial lesions are pinhead-sized papules that coalesce to form a brick red, irregular, blotchy maculopapular rash

  • Spreads to the trunk and extremities, including the palms and soles

  • Lasts for 3–7 days and fades in the same manner it appeared

• Koplik spots

  • Small, irregular, and red with whitish center on the mucous membranes

  • Appear about 2 days before the rash and last 1–4 days as tiny "table salt crystals" on the palatal or buccal mucosa opposite the molars or on vaginal membranes

• Other findings

  • Pharyngeal erythema

  • Tonsillar yellowish exudate

  • Coating of the tongue in the center with a red tip and margins

  • Moderate generalized lymphadenopathy

  • Splenomegaly

Differential Diagnosis

• Kawasaki disease

• May be mistaken for other exanthematous infections

• Koplik spots are pathognomonic

• Leukopenia usually present unless secondary bacterial complications exist

• Thrombocytopenia is common

• Proteinuria is often observed

• Real-time reverse transcriptase-polymerase chain reaction (RT-PCR), available from the CDC and some public health laboratories, can help establish a diagnosis

• Detection of IgM measles antibodies with ELISA or fourfold rise in measles antibody titer is diagnostic

• IgM assays can be falsely negative the first few days of infection and falsely positive in the presence of rheumatoid factor or with acute rubella, erythroparvovirus (parvovirus B19), or HHV-6 infection

• Administer antipyretics and fluids as needed

• Vitamin A supplementation for all children

  • 200,000 units/day orally for 2 days to children with measles more than 1-year-old

  • 100,000 units/day for children 6–12 months old

  • 50,000 units/day for children younger than 6 months)

  • A third dose is recommended 2–4 weeks later for children with vitamin A deficiency

• Ribavirin is used in selected severe cases of pneumonitis, but insufficient data prevent recommending antiviral use

• Zinc has a role in the maintenance of normal immune functions, but insufficient data are available to recommend zinc supplementation to children with measles

Complications

• Otitis media (the most common complication)

• Postinfectious encephalomyelitis

• Inclusion body encephalitis

• Subacute sclerosing panencephalitis (SSPE) is very rare

• Bronchopneumonia or bronchiolitis

• Bronchiectasis may occur in up to one-quarter of nonvaccinated children

• Cervical adenitis

• Pneumonia

• Diarrhea and protein-losing enteropathy are significant complications among malnourished children

• Conjunctivitis, keratitis, and otosclerosis

Prevention

• See Table 30–7

• Vaccine coverage rates must exceed 95% to prevent outbreaks

• One vaccine dose is about 93% effective

• Two doses of vaccine are estimated to be 97% protective

• MMR and MMRV vaccine should not be administered to pregnant women, patients with anaphylactic reactions to neomycin, and patients with known primary or acquired immunodeficiency

• Asymptomatic patients living with HIV infection with CD4 counts higher than 200 cells/mcL should receive MMR vaccine but not MMRV vaccine

• Illness confers permanent immunity

Prognosis

• An estimated 21.1 million deaths were prevented between 2000 and 2017 by use of measles vaccination

• In the United States, the case fatality rate is around 2 per 1000 reported cases, with deaths principally due to respiratory and neurologic complications

• Deaths in the developing world are mainly related to diarrhea and protein-losing enteropathy

• Pregnant women with measles may be at increased risk for death

When to Refer

• Any suspect cases should be reported to public health authorities

• HIV infection

• Pregnancy

When to Admit

• Meningitis, encephalitis, or myelitis

• Severe pneumonia

• Diarrhea that significantly compromises fluid or electrolyte status