Review Question - QID 217088

This patient has measles as evidenced by her high fever, cough, conjunctivitis, Koplik spots (whitish lesions on the buccal mucosa), and a downward-spreading maculopapular rash. Measles is an RNA virus that is enveloped, single-stranded, non-segmented, and negative-sense.

Measles (rubeola) is an extremely contagious but preventable viral disease. It belongs to the Paramyxoviridae family. Its classic presentation includes Koplik spots (pathognomonic), which are followed by the 3 C’s (cough, conjunctivitis, and coryza) and a caudally spreading rash that precedes fever. It is spread by aerosolized respiratory droplets and has an incubation period of around 2 weeks. While most can recover, a serious potential complication is subacute sclerosing panencephalitis, a neurodegenerative disease with both cognitive and motor dysfunction. The envelope of the virus helps avoid immune system detection in addition to facilitating droplet transmission. It also has glycoproteins that assist with binding and identifying host cells. Measles can be prevented by the MMR vaccine delivered at ages 1 and 4-5. Treatment is primarily supportive.

Bester provides an overview of measles and its vaccination. Following infection, immune suppression can follow for several months. While no antivirals exist for measles, vitamin A supplementation is recommended to decrease mortality for younger patients. Elimination of measles in a population can be achieved with 2 doses of the MMR vaccine with coverage of at least 93% of the population.

Incorrect Answers:
Answer 1: Enveloped, linear, non-segmented, double-stranded virus can describe poxviruses like the smallpox virus. Smallpox is characterized by lesions that synchronously evolve from macules to umbilicated vesicles. It is a DNA virus that belongs to the Poxviridae family.

Answer 3: Enveloped, single-stranded, non-segmented, positive-sense virus can describe rubella, which is an RNA virus in the Matonaviridae family. Also known as German measles, rubella is another common viral exanthem, but can also present with polyarthralgia and/or postauricular lymphadenopathy. In comparison to measles, rubella has a rash that resolves in around 3 days. However, it does not present with Koplik spots.

Answer 4: Enveloped, single-stranded, segmented, negative-sense virus can describe influenza, which is an RNA virus in the Orthomyxoviridae family. While the patient developed a high fever and cough, influenza does not present with a rash or Koplik spots.

Answer 5: Non-enveloped, linear, non-segmented, single-stranded virus describes parvovirus B19, which is a DNA virus that belongs to the Parvoviridae family. It causes erythema infectiosum, which is characterized by an erythematous rash of the cheeks and reticular rash of the trunk. While this patient has a rash, the Koplik spots are pathognomonic for measles.

Bullet Summary:
Measles is an enveloped, single-stranded, non-segmented, negative-sense virus that is characterized by Koplik spots, maculopapular rash, cough, conjunctivitis, and coryza.