Rubella (German Measles)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Rubella, also known as German measles, is a contagious viral infection characterised by a distinctive red-pink rash. It primarily affects children and is generally mild, but can have serious consequences if contracted by pregnant women, as it can lead to congenital rubella syndrome in the unborn child. Rubella is preventable through vaccination and has become rare in countries with high immunisation rates.

Aetiology

Rubella is caused by the rubella virus, which is a member of the Togaviridae family. The virus is primarily spread through respiratory droplets when an infected person coughs or sneezes, and can also be transmitted via direct contact with nasal or throat secretions. It is highly contagious, particularly during the period from 1 week before to 1 week after the rash appears.

Pathophysiology

After the rubella virus enters the body through the respiratory tract, it replicates in the nasopharynx and lymph nodes. The virus then spreads to the bloodstream (viraemia), which leads to systemic infection. The characteristic rash of rubella is a result of the body’s immune response to the virus. In pregnant women, the virus can cross the placenta, infecting the developing foetus and leading to congenital rubella syndrome, which can cause severe birth defects.

Risk Factors

• Lack of vaccination: Children who have not received the MMR (measles, mumps, and rubella) vaccine are at higher risk of contracting rubella.
• Pregnancy: Pregnant women who are not immune to rubella are at risk of passing the infection to their unborn baby, leading to serious complications.
• Travel: Travel to areas with low vaccination rates or rubella outbreaks increases the risk of contracting the virus.
• Close contact with infected individuals: Living or spending time with someone who has rubella increases the risk of transmission.

Signs and Symptoms

The symptoms of rubella are generally mild in children and often include:

• Fever: A low-grade fever (below 38.5°C) is common.
• Rash: A red-pink rash typically starts on the face and spreads downward to the trunk and limbs. It usually lasts 3 to 5 days.
• Swollen lymph nodes: Particularly at the back of the neck and behind the ears.
• Cold-like symptoms: Runny nose, sore throat, and mild conjunctivitis (red eyes).
• Joint pain: More common in older children and adolescents, particularly in females.
• Fatigue: General malaise and tiredness.

In some cases, rubella can be asymptomatic, especially in young children.

Investigations

Rubella is primarily diagnosed through clinical presentation, but confirmation may require laboratory testing, particularly in pregnant women or cases where the diagnosis is unclear:

• Serology: Blood tests can detect rubella-specific IgM antibodies, which confirm recent infection, or IgG antibodies, which indicate immunity due to past infection or vaccination.
• PCR testing: Polymerase chain reaction (PCR) testing can be used to detect the rubella virus in throat swabs, urine, or blood, especially in cases of suspected congenital rubella syndrome.
• Prenatal testing: Pregnant women exposed to rubella may undergo amniocentesis to test for the virus in amniotic fluid if infection is suspected.

Management

There is no specific antiviral treatment for rubella, and management is primarily supportive. The focus is on relieving symptoms and preventing complications, particularly in pregnant women.

Supportive Care:

• Fever and pain relief: Paracetamol or ibuprofen can be used to reduce fever and alleviate discomfort.
• Rest: Encourage plenty of rest to help the body recover.
• Hydration: Ensure the child stays hydrated by drinking plenty of fluids.

Prevention:

The best way to prevent rubella is through vaccination:

• MMR vaccine: The MMR vaccine protects against measles, mumps, and rubella. It is routinely given to children in the UK at 12 months of age, with a second dose at 3 years and 4 months. Vaccination is highly effective and has led to a dramatic decrease in rubella cases.
• Isolation: Children with rubella should stay away from school or childcare settings for at least 5 days after the rash appears to prevent the spread of the virus.

Pregnancy Considerations:

If a pregnant woman is exposed to rubella, prompt testing and referral to a specialist are necessary. In cases of confirmed rubella infection during pregnancy, there is a high risk of miscarriage or severe congenital abnormalities (congenital rubella syndrome). Specialist care and counselling are essential.

References

1. NHS (2023). Rubella (German Measles): Causes, Symptoms and Treatment. Available at: NHS Website
2. NICE (2024). Rubella: Diagnosis and Management Guidelines. Available at: NICE Guidance
3. British Medical Journal (BMJ) (2022). Rubella and Congenital Rubella Syndrome: Clinical Management. Available at: BMJ