Infectious Disease · Viral Parotitis
The facts most likely to be tested
Mumps is caused by a paramyxovirus that typically presents with bilateral parotitis and fever.
The most common extra-salivary complication in post-pubertal males is orchitis, which carries a risk of infertility.
Mumps is a leading cause of aseptic meningitis in unvaccinated populations, often presenting with nuchal rigidity and headache.
Physical examination reveals erythema and edema of Stensen's duct opening, which is a pathognomonic finding for parotitis.
Diagnosis is primarily clinical, but can be confirmed via RT-PCR or viral culture of a buccal swab.
Prevention is achieved through the live-attenuated MMR vaccine, which is administered in two doses at ages 12-15 months and 4-6 years.
Management of mumps is supportive, consisting of hydration, analgesics, and warm or cold compresses for parotid swelling.
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A 19-year-old male college student presents to the urgent care clinic with a 3-day history of fever, malaise, and bilateral ear pain. On physical exam, he has bilateral parotid gland swelling and erythema of the Stensen's duct openings. He reports he is unsure of his childhood vaccination status. Two days later, he develops severe unilateral testicular pain and scrotal swelling.
What is the most likely diagnosis and the most common serious complication in this patient?
Mumps complicated by orchitis.
The patient's presentation of bilateral parotitis and subsequent orchitis is classic for mumps, which is tested via the association between parotitis and post-pubertal male reproductive complications.
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Etiology / Epidemiology
Caused by Paramyxovirus; primarily affects unvaccinated children and young adults in crowded settings.
Clinical Manifestations
Presents with parotitis and fever; Stensen's duct inflammation is pathognomonic.
Diagnosis
RT-PCR of buccal swab is the gold standard for confirmation.
Treatment
Supportive care with hydration and analgesics; no antiviral therapy exists.
Prognosis
Self-limiting; orchitis is the most common complication in post-pubertal males.
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Epidemiology & Etiology
Mumps is a highly contagious Paramyxovirus transmitted via respiratory droplets. Incidence is highest in unvaccinated populations or during outbreaks in college dormitories and military barracks. The incubation period typically lasts 16–18 days.
Pertinent Anatomy
The virus exhibits tropism for the parotid glands, leading to swelling that obscures the angle of the mandible. Inflammation of the Stensen's duct (parotid duct) orifice is a hallmark clinical finding.
Pathophysiology
The virus enters the respiratory tract, replicates in the nasopharynx and regional lymph nodes, and spreads via viremia to glandular and CNS tissues. Systemic involvement occurs due to the virus's affinity for glandular epithelium and the meninges.
Clinical Manifestations
Patients present with prodromal fever, malaise, and myalgia followed by bilateral or unilateral parotitis. Look for erythema and edema of the Stensen's duct. Orchitis is a major concern in post-pubertal males, presenting with severe testicular pain and swelling, which carries a risk of infertility.
Diagnosis
Diagnosis is primarily clinical, but RT-PCR of a buccal or oral swab is the gold standard for laboratory confirmation. Serum IgM antibodies may be used but can yield false negatives in early infection. Amylase levels are frequently elevated due to parotid involvement.
Treatment
Management is strictly supportive care including rest, fluids, and NSAIDs for pain. Aspirin should be avoided in children due to the risk of Reye syndrome. Isolation is required for 5 days after the onset of parotitis to prevent transmission.
Prognosis
Most cases resolve within 10 days. Complications include aseptic meningitis, pancreatitis, and sensorineural hearing loss. Orchitis occurs in 20-30% of post-pubertal males, though sterility is rare.
Differential Diagnosis
Suppurative parotitis: usually unilateral with purulent discharge from the duct
Sialolithiasis: pain exacerbated by eating, often with a palpable stone
HIV parotitis: typically painless and associated with lymphadenopathy
Parainfluenza: lacks the classic parotid swelling pattern
Neoplasm: firm, fixed mass rather than acute inflammatory swelling