Mumps
In the United States, aggressive vaccination has significantly decreased the prevalence of mumps sialadenitis, with approximately 300 cases reported annually (Barskey, et al, 2013).
Mumps is a specific acute viral infection due to a paramyxovirus, an RNA virus that belongs to the influenza and para-influenza family. In 85% of cases, it affects the school-age children under the age of 15 years, with an incubation period of 2 to 3 weeks. The illness starts by 1 to 2 days of prodromal influenza-like syndrome (discomfort, loss of appetite, nausea, chills, fever, sore throat, and headache), followed by the appearance of the characteristic face swelling. The patient is infectious from 3 days before the onset of salivary swellings to 7 days after, through airborne droplets of infected saliva. A single episode of infection confers lifelong immunity. Fortunately, this condition has been mostly eradicated as a result of vaccination (McQuone, 1999).
The swelling, which that usually starts unilateral and in a few days becomes bilateral, lasts from a couple of days to one week (Figure 1). The virus causes fever and is considered the commonest cause of acute painful profuse swelling of the parotid gland.
The gland is soft and tender, but never suppurates. Impingement on the auriculotemporal and great auricular nerves causes much pain as the gland is pressured during mastication. Symptoms usually resolve within 5 to 10 days.
Mumps may be complicated by pancreatitis, orchitis, and oophoritis. It might be a cause of abortion during the first trimester of pregnancy because of fetal endocardial fibroelastosis. Sensorineural deafness (1/20,000) and meningo-encephalitis are rare, but are more likely to occur in adults.
Figure 1.
Mumps in a 10-month child with a smooth enlargement of the right parotid gland
Laboratory findings include leukocytopenia with relative lymphocytosis. Serum amylase peaks in the 1st week and normalizes by the 2nd or 3rd week. Soluble antibodies directed against the nucleoprotein core of the virus appear within the final week of infection, and disappear within 8 months. Antibodies directed against the outer surface appear several weeks after soluble antibodies, and persist for 5 years. Mumps is a self-limited disease that requires rest and symptomatic treatment only, which includes antibiotics, sialagogues and rehydration (McQuone, 1999).
Human Immunodeficiency Virus (HIV)-Associated Sialadenitis
The presentation of HIV-associated sialadenitis is in the form of chronic, bilateral enlargement of parotid glands where the glands are painless, hard and nodular. The disease is more common among children than among adults. The condition may be associated with xerostomia and xerophthalmia, being so similar to the classical Sjogren's syndrome in adulthood. Although, both conditions share similar histological characteristics, yet, HIV-associated sialadenitis is usually associated with a negative autoantibody screen. Multiple glandular cysts causing gross parotid swelling and facial disfigurement is another pattern of presentation. Thirty percent of HIV-infected children have been reported to have enlargement of their parotid glands. In addition, patients with HIV are more susceptible to infection with cytomegalovirus (CMV) and adenoviruses as causative agents for non-mumps parotitis (Huang, 1991; Schoidt, 1989).
Useful imaging tools include ultrasound (US), computed tomography (CT) scan and magnetic resonance imaging (MRI). The latter two demonstrate the characteristic ‘Swiss cheese’ appearance of multiple large cystic lesions (Figure 2). These tools can also guide fine-needle aspiration (FNA), which reveals serous fluid with the presence of lymphocytes and macrophages. As the parotid gland contains many lymph nodes (LNs) at different levels, they might be enlarged as the HIV virus mainly affects the lymphoid tissue. The sole indication of surgery in such cases might be to improve the esthetic appearance (Huang, 1991; Schoidt, 1989).
Figure 2.
MRI showing the characteristic Swiss-cheese appearance of multiple large cystic lesions