Overview
Definition:
Mumps is an acute viral illness caused by the mumps virus, a paramyxovirus
While typically self-limiting, it can lead to significant complications affecting various organ systems, most notably the testes (orchitis) and central nervous system (meningitis/encephalitis).
Epidemiology:
Before widespread vaccination, mumps was a common childhood illness, peaking in late winter and spring
With the Measles-Mumps-Rubella (MMR) vaccine, incidence has dramatically decreased, but outbreaks can still occur in unvaccinated or under-vaccinated populations
Complications are less frequent with vaccination.
Clinical Significance:
Understanding mumps complications is crucial for pediatric residents to diagnose and manage these serious sequelae, prevent long-term sequelae like infertility from orchitis, and recognize neurological involvement
Prompt diagnosis and supportive care are key.
Clinical Presentation
Mumps Orchitis:
Sudden onset of testicular pain and swelling, typically unilateral but can be bilateral
Fever, nausea, vomiting, and headache may accompany testicular involvement
Onset is usually 4-8 days after parotid swelling begins or as a sole manifestation
Testicular atrophy may occur.
Mumps Meningitis:
Characterized by fever, headache, nuchal rigidity, photophobia, and sometimes vomiting
Neurological signs like lethargy or irritability can be present
Typically occurs during or shortly after the prodromal phase of parotitis
Usually benign and self-limiting.
Mumps Encephalitis:
Less common than meningitis, presenting with more severe neurological symptoms including confusion, seizures, focal neurological deficits, and coma
Can have significant morbidity and mortality
Differentiated from meningitis by more profound CNS dysfunction.
Diagnostic Approach
History Taking:
Detailed history of vaccination status is paramount
Ask about fever, headache, neck stiffness, photophobia, testicular pain/swelling, and any recent contact with a known mumps case
Note any preceding or concurrent parotitis.
Physical Examination:
For orchitis: Unilateral or bilateral testicular tenderness, marked swelling, and erythema of the scrotum
Epididymal tenderness may also be present
For meningitis/encephalitis: Assess for nuchal rigidity, Kernig's and Brudzinski's signs, altered mental status, and focal neurological deficits
Examine for parotid swelling.
Investigations:
Diagnosis is primarily clinical
Confirmation can be done via serology (IgM antibodies against mumps virus), viral isolation from saliva, urine, or CSF, or RT-PCR of these samples
Cerebrospinal fluid (CSF) analysis in meningitis typically shows lymphocytic pleocytosis, elevated protein, and normal glucose.
Differential Diagnosis:
For orchitis: Bacterial epididymitis, testicular torsion, incarcerated hernia, trauma
For meningitis/encephalitis: Other viral meningoencephalitides (enterovirus, HSV), bacterial meningitis, aseptic meningitis from other causes, Guillain-Barré syndrome.
Management
Orchitis Management:
Primarily supportive care
Bed rest, scrotal support, and analgesics (e.g., paracetamol, ibuprofen) for pain and fever
Cold compresses may provide symptomatic relief
Steroids have been used but evidence for significant benefit in preventing atrophy is limited
Close monitoring for testicular atrophy.
Meningitis Management:
Supportive care is the mainstay
Hospitalization for monitoring
Analgesics for headache and fever
Hydration and electrolyte balance
Antiemetics if vomiting is severe
Antiviral therapy is not indicated for mumps meningitis
Typically resolves within 7-10 days.
Encephalitis Management:
Aggressive supportive care in an ICU setting may be required
Management of seizures with anticonvulsants
Intracranial pressure monitoring if indicated
Careful fluid and electrolyte management
Antivirals are not effective against mumps encephalitis
Steroids may be considered in severe cases, but evidence is debated.
Supportive Care:
Adequate hydration and nutrition are important for all complications
Monitor vital signs closely
Neurological assessment for CNS involvement
Pain management tailored to the specific complication.
Complications
Early Complications:
Orchitis (most common in post-pubertal males), oophoritis (less common in females), pancreatitis, myocarditis, deafness (rare, can be unilateral or bilateral), encephalitis, meningitis.
Late Complications:
Testicular atrophy and infertility in males with severe orchitis
Permanent neurological sequelae from encephalitis (rare)
Hearing loss from deafness
Recurrent parotitis is rare.
Prevention Strategies:
The most effective prevention is vaccination with the MMR vaccine
Ensuring high vaccination coverage in the community significantly reduces the incidence of mumps and its complications
Public health measures for outbreak control in unvaccinated populations.
Prognosis
Factors Affecting Prognosis:
For orchitis, the severity and bilaterality can influence the risk of infertility
For meningitis, the prognosis is generally excellent with full recovery
For encephalitis, prognosis varies widely, with severe cases carrying risk of permanent neurological damage or death.
Outcomes:
Most cases of mumps resolve without sequelae
Mumps meningitis is almost always benign
Mumps encephalitis has a variable outcome, with significant recovery in most, but potential for long-term deficits
Orchitis can lead to testicular atrophy and infertility in a proportion of affected males.
Follow Up:
For orchitis, follow-up may be needed to monitor for testicular atrophy and assess fertility if desired
For meningitis and encephalitis, neurological assessment may be warranted post-recovery, especially in severe cases
Routine follow-up is not typically required for uncomplicated mumps.
Key Points
Exam Focus:
MMR vaccine is key to prevention
Orchitis is common in post-pubertal males, with risk of atrophy/infertility
Mumps meningitis is usually benign (lymphocytic pleocytosis on CSF)
Mumps encephalitis is rare but serious.
Clinical Pearls:
Always inquire about vaccination status in suspected mumps cases
Differentiate testicular pain from torsion vs
orchitis
Recognize early signs of CNS involvement
Supportive care is primary for most complications.
Common Mistakes:
Underestimating the potential for serious complications like orchitis and encephalitis
Delaying diagnosis of meningitis/encephalitis due to atypical presentation
Failure to adequately investigate testicular pain in a child with mumps.