Mumps

Mumps, also known as epidemic parotitis, is a highly contagious viral disease caused by the mumps virus, a member of the Paramyxoviridae family. The disease is characterised by painful swelling of the parotid glands and a range of non-specific symptoms such as fever, headache, malaise, muscle pain, and loss of appetite.

Mumps primarily affects children and is most commonly spread through respiratory droplets and direct contact with infected saliva.

Signs and Symptoms

The incubation period for mumps ranges from 7 to 25 days, with symptoms typically appearing 16 to 18 days after exposure. Initial symptoms include fever, headache, muscle pain, and loss of appetite. The hallmark symptom is parotitis, or swelling of the parotid glands, which occurs in about 90% of symptomatic cases. This swelling usually lasts 2 to 3 days but can extend to a week or longer. Other salivary glands, such as the submandibular and sublingual glands, may also be affected.

Complications, though rare, can be severe. These include orchitis (inflammation of the testes), oophoritis (inflammation of the ovaries), pancreatitis, and aseptic meningitis. Orchitis occurs in 10-40% of post-pubertal males and can lead to reduced fertility. Mumps meningitis occurs in 5-10% of cases and can result in severe headaches, vomiting, and neck stiffness. Other complications include encephalitis, which affects less than 0.5% of cases, and deafness, occurring in about 4% of cases.

Diagnosis

In regions where mumps is widespread, diagnosis is often based on clinical presentation, particularly the presence of parotitis. In areas where mumps is less common, laboratory tests are necessary to confirm the diagnosis. These tests include antibody testing, viral cultures, and reverse transcription polymerase chain reaction (rRT-PCR) to detect mumps virus RNA. Lumbar puncture may be performed in cases of meningitis to rule out other causes, revealing elevated white blood cell counts and protein levels in cerebrospinal fluid.

Prevention

Mumps is preventable through vaccination. The MMR vaccine, which protects against measles, mumps, and rubella, is the most commonly used vaccine. The MMRV vaccine also includes protection against varicella (chickenpox). Vaccination is typically administered in early childhood, but can also be given in adolescence or adulthood if needed. The MMR vaccine is highly effective, though its effectiveness is higher after two doses compared to one. Despite high vaccination rates, outbreaks can still occur due to factors such as waning immunity and low vaccination coverage in certain regions.

Treatment

There is no specific antiviral treatment for mumps; management is supportive. This includes rest, hydration, and pain relief. Anti-fever medications, excluding aspirin in children due to the risk of Reye syndrome, can help manage fever. Analgesics may be used to control pain, particularly in cases of orchitis. In severe neurological cases, ventilatory support may be necessary. Intramuscular immunoglobulin may benefit some cases if administered early, though its effectiveness in outbreaks is limited. Antibiotics may be prescribed to prevent secondary bacterial infections.

Prognosis

The prognosis for mumps is generally excellent, with most cases resolving within two weeks without long-term complications. However, complications such as orchitis can lead to testicular atrophy and reduced fertility in some cases. Deafness, though rare, can be permanent. The overall case-fatality rate is low, between 1.6 and 3.8 per 10,000 cases, typically occurring in those who develop encephalitis.

Mumps remains a significant public health concern, particularly in regions with low vaccination rates. Continued efforts to improve vaccine coverage and address factors contributing to outbreaks are essential in controlling the spread of this disease.

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Self-assessment MCQs (single best answer)

What is the primary cause of mumps?

Which family does the mumps virus belong to?

What is the most characteristic symptom of mumps?

Which of the following is a common complication of mumps in post-pubertal males?

How is mumps primarily transmitted?

Which of the following diagnostic tests is commonly used to confirm mumps in areas where it is less common?

Which vaccine is used to prevent mumps?

Which of the following is NOT a recommended treatment for mumps?

What is the approximate incubation period for mumps?

What is the typical case-fatality rate for mumps?