Infectious Disease · Viral Infections
The facts most likely to be tested
Mumps is caused by the Mumps virus, a paramyxovirus transmitted via respiratory droplets.
The classic clinical presentation is bilateral parotitis characterized by parotid gland swelling and earlobe displacement.
Orchitis is the most common post-pubertal complication, which carries a risk of infertility if bilateral.
Aseptic meningitis is the most common neurological complication of mumps infection.
Pancreatitis is a rare but serious systemic complication associated with mumps infection.
Diagnosis is primarily clinical, but can be confirmed via RT-PCR or viral culture of a buccal swab.
Prevention is achieved through the MMR vaccine, which is a live-attenuated vaccine administered in two doses.
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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 painful swelling in front of his ears. Physical examination reveals bilateral parotid gland enlargement with upward and outward displacement of the earlobes. He reports that his testicular pain began this morning. He is unsure of his childhood vaccination status.
What is the most likely diagnosis and the most significant long-term risk associated with his current testicular symptoms?
Mumps; infertility
The patient's presentation of bilateral parotitis and orchitis is classic for mumps. Orchitis is a common post-pubertal complication that can lead to testicular atrophy and infertility.
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Etiology / Epidemiology
Viral infection caused by Paramyxovirus; primarily affects unvaccinated children and young adults.
Clinical Manifestations
Presents with parotitis and orchitis; bilateral parotid swelling is the classic board finding.
Diagnosis
RT-PCR of buccal swab is the gold standard; elevated serum amylase is common.
Treatment
Supportive care with hydration and analgesics; avoid aspirin due to Reye syndrome risk.
Prognosis
Usually self-limiting; orchitis is the most common complication in post-pubertal males.
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Epidemiology & Etiology
Caused by the Paramyxovirus, transmitted via respiratory droplets. Incidence is highest in unvaccinated populations or settings with close contact like college dorms. Outbreaks occur despite the MMR vaccine due to waning immunity.
Pertinent Anatomy
The virus targets the parotid glands, causing inflammation and ductal obstruction. Swelling often obscures the angle of the mandible, a key physical exam landmark.
Pathophysiology
The virus replicates in the upper respiratory tract and regional lymph nodes before systemic viremia. It exhibits high affinity for glandular tissue and the central nervous system. This systemic spread explains the multi-organ involvement beyond the salivary glands.
Clinical Manifestations
Prodrome includes fever, headache, and myalgia followed by parotitis. Look for Stensen's duct inflammation. Red flags include signs of aseptic meningitis (nuchal rigidity) or orchitis (testicular pain/swelling), which can lead to infertility.
Diagnosis
The RT-PCR of a buccal swab is the gold standard for confirmation. Serum IgM antibodies are useful but may be falsely negative in vaccinated individuals. Elevated serum amylase (salivary origin) is a supportive, non-specific finding.
Treatment
Management is strictly supportive care including rest, fluids, and NSAIDs for pain. Aspirin is strictly contraindicated 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. Orchitis occurs in 20-30% of post-pubertal males; while painful, it rarely causes permanent sterility. Monitor for aseptic meningitis or pancreatitis as rare but serious sequelae.
Differential Diagnosis
Sialadenitis: usually bacterial, associated with ductal stones and purulent discharge
Sjogren syndrome: chronic, bilateral, associated with dry eyes and mouth
Parotid tumor: firm, fixed mass, usually unilateral and painless
HIV parotitis: associated with lymphadenopathy and chronic course
Bulimia: bilateral parotid hypertrophy due to chronic vomiting