Model Answer
0 min readIntroduction
Measles, also known as rubeola, is a highly contagious viral disease that remains a significant public health concern globally, particularly in developing countries. It is caused by the measles virus, a single-stranded, enveloped RNA virus of the paramyxovirus family. Characterized by a distinctive maculopapular rash, measles can lead to severe complications, including pneumonia, encephalitis, and even death. Understanding its clinical features is crucial for prompt diagnosis and effective management, preventing further transmission and minimizing morbidity and mortality. This answer will detail the clinical presentation of measles, from initial prodromal symptoms to the characteristic rash and potential complications.
Clinical Features of Measles
The clinical course of measles can be divided into distinct phases: incubation, prodrome, exanthem (rash), and convalescence.
1. Incubation Period
The incubation period, from exposure to the first symptoms, typically lasts 10-14 days. During this time, the virus is replicating, and the individual is not infectious.
2. Prodromal Phase (2-4 days)
This phase marks the onset of symptoms before the appearance of the rash. Key features include:
- Fever: High fever, often reaching 104°F (40°C), is usually the first symptom.
- Cough: A dry, hacking cough develops, often worsening over time.
- Coryza: Runny nose with clear discharge.
- Conjunctivitis: Red, watery eyes, often with photophobia (sensitivity to light).
- Koplik Spots: These are pathognomonic (unique) for measles. They appear as small, white spots with bluish-white centers on a red background, typically found on the buccal mucosa (inner lining of the cheeks) 2-3 days before the rash.
3. Exanthem Phase (Rash)
The rash typically appears 14 days after exposure, starting on the face (around the hairline) and spreading downwards to the neck, trunk, and extremities. The rash is:
- Maculopapular: Consisting of flat, red spots (macules) and small, raised bumps (papules).
- Confluent: The spots often merge together, forming larger patches.
- Progressive: The rash spreads over 3-5 days.
- Fading: As the rash fades, it leaves behind brownish discoloration and mild desquamation (scaling).
4. Convalescence Phase
This phase follows the resolution of the rash. Symptoms gradually subside, but a lingering cough may persist for several weeks. The individual remains infectious for approximately 4 days after the appearance of the rash.
Complications of Measles
Measles can lead to several serious complications, particularly in young children, malnourished individuals, and those with weakened immune systems:
- Pneumonia: The most common cause of measles-related death.
- Encephalitis: Inflammation of the brain, leading to neurological damage.
- Otitis Media: Middle ear infection.
- Diarrhea: Often severe and can lead to dehydration.
- Subacute Sclerosing Panencephalitis (SSPE): A rare but fatal degenerative disease of the central nervous system that develops years after the initial measles infection.
- Corneal Ulceration: Can lead to blindness.
Diagnosis
Diagnosis is typically based on clinical presentation, especially the presence of Koplik spots and the characteristic rash. Laboratory confirmation can be achieved through:
- Measles-specific IgM antibody detection: Indicates recent infection.
- Measles virus RNA detection by RT-PCR: Highly sensitive and specific.
Conclusion
Measles presents with a characteristic clinical course, progressing from prodromal symptoms like fever, cough, coryza, and conjunctivitis, to the appearance of a maculopapular rash and potential complications. Early diagnosis, based on clinical features and confirmed by laboratory testing, is crucial for effective management and prevention of transmission. Vaccination remains the most effective strategy for controlling measles and preventing its devastating consequences. Continued efforts to achieve and maintain high vaccination coverage are essential for global measles elimination.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.