Up to half of infections are asymptomatic or lead to nonspecific respiratory symptoms. Unilateral or bilateral parotitis lasting >2 days is present in 70-90% of symptomatic infections.

• A prodrome involving low-grade fever, malaise, myalgia, headache, and anorexia may precede the development of parotitis and last for 1-7 days.
  • - Pts with parotitis typically have difficulty eating, swallowing, and/or talking and may have an earache.
  • - Glandular swelling disappears within 1 week.
• Epididymo-orchitis is the second most common manifestation of mumps, developing in 15-30% of cases in postpubertal males.
  • - Orchitis, characterized by a painful, tender, and enlarged testis, is bilateral in 10-30% of cases and resolves within 1 week.
  • - Oophoritis (manifested by lower abdominal pain and vomiting) occurs in ~5% of women with mumps.
  • - Sterility after mumps is rare.
• Symptomatic CNS disease (e.g., aseptic meningitis) occurs in <10% of pts and is usually self-limited.
  • - In CSF pleocytosis, neutrophils often predominate in the first 24 h before being replaced by lymphocytes on the second day.
  • - Cranial nerve palsies occasionally lead to permanent sequelae, particularly deafness.
• Less common manifestations include pancreatitis, myocarditis, thyroiditis, nephritis, and arthritis. Mumps in pregnancy does not appear to lead to premature birth, low birth weight, or fetal malformations.