Things That Go ‘Mump’ in the Night: What to do with Parotid Swelling
CASE
A healthy graduate student presents to the ER in the middle of the night with facial swelling and voice hoarseness. She states that she has been feeling generally unwell with aches and a sore throat for the past two days. Tonight, she took a throat lozenge shortly before going to bed, but awoke a while later with worsening hoarseness, throat tightness, and facial swelling. She states that the swelling is over her jawline and appears symmetric. She provides her license photo, which shows a dramatic difference in the contour of her mandible.
She is allergic to cats, but denies any recent exposure. She has no other known allergies and multiple prior exposures to this brand of throat lozenge. She denies wheezing, abdominal discomfort, and rash. She is only on birth control. She denies any inhalational drug use. She denies any dental pain or recent dental manipulation.
Her vital signs are within normal limits and she is afebrile. She has no stridor, drooling, or dysphonia, but exam demonstrates marked bilateral parotid/submandibular swelling. The region is not tender nor is it erythematous or warm. Her uvula is midline and without swelling. No lesions are noted in the posterior oropharynx. The tongue is unremarkable. She endorses ongoing throat tightness.
Lab work is obtained. She has a mild leukocytosis to 12.8. EBV and Strep are both negative. Given the extent of swelling and her subjective complaint of throat tightness, you obtain CT imaging (Figure 1).
Figure 1: CT neck.
The radiologist calls you to discuss the case. He says that she has enlargement of bilateral parotid glands and submandibular glands. He notes extensive subcutaneous edema in the retromandibular tissues and upper neck. Fortunately he says her airway looks patent. He inquires, “What do you think is going on?”
You start to worry that she may have mumps. You’ve never seen mumps, but you know it exists. Time for a quick review…
The Background
Mumps is a viral illness that is generally preventable by vaccine.
Peak incidence is late winter and early spring.
Mumps still occurs in outbreaks in closed environments such as college dormitories, military barracks, and schools, but is rare <1 yo due maternal antibodies.
An outbreak is defined as ≥3 cases linked by place and time.
Mumps is much more likely to occur in unvaccinated individuals than in vaccinated individuals, but there are rare reports of vaccinated patients developing mumps.
Transmission occurs by direct contact, respiratory droplets and fomites. Viral shedding precedes onset of symptoms.
Prolonged incubation period of 12-25 days.
The Presentation
There is often a non-specific prodrome of myalgias, headache, fever, and malaise.
Salivary gland swelling usually occurs within the first 2-3 days of symptom onset.
The hallmark of mumps is parotid swelling. It can be painful and tender, but not always, and can last up to 10 days.
The swelling can be unilateral (25% of cases) or bilateral. The swelling can start on one side and then progress to involve both sides.
Other salivary glands such as the sublingual glands and submandibular glands can swell, but this only occurs in 10% of cases.
Associated complications:
Orchitis (typically develops 5-10 days following parotitis with high fevers and severe testicular pain).
Meningitis (more common in males. May develop before, during or after parotitis. In some cases, meningitis occurs in the absence of parotitis. Associated with CSF pleocytosis).
Other rare complications: encephalitis, pancreatitis, and arthritis.
The Differential
Many other viral infections can cause parotid swelling (EBV, HSV, HIV, CMV, coxsackie, etc.).
Bacterial parotitis presents as typically firm, tender swelling associated with high fevers and toxic appearance. S.aureus is most often implicated.
Salivary gland stone, salivary tumor, sarcoidosis, Sjögren's syndrome.
The Work-up
Patient should be placed on droplet precautions.
At the time of presentation, two laboratory specimens should be drawn. A serum mumps IgM level and a buccal or oral swab should be sent for RT-PCR. At our institution, these are send-out labs.
The IgM level should be sent in a red-top tube.
The IgM level is not always accurate if the sample is obtained within the first 5-days of symptom onset. Therefore, if the IgM level returns as normal and the RT-PCR has not resulted (or was never sent), the CDC recommends a second serum sample be sent 5-10 days after symptom onset.
It is recommended that the parotid gland be “milked” and the swab be taken from the site of Stensen’s duct (buccal mucosa).
The swab used for strep testing can be used for the buccal swab.
Buccal swabs should be obtained as soon as possible after symptom onset. It provides the best means for laboratory confirmation, particularly in patients who have been vaccinated.
A CBC typically demonstrates leukopenia and a relative lymphocytosis.
Often serum amylase will be elevated.
The Treatment
No specific treatment.
20-30% of cases are asymptomatic.
Supportive care with NSAIDs/Tylenol.
If a patient is admitted, they should be placed on droplet precautions until parotid swelling resolves.
Individuals treated on an outpatient basis should remain at home and minimize contact with others for five days following symptom onset.
Vaccination:
Patients who are incompletely immunized and at risk during a mumps outbreak (i.e. college students on a campus with mumps cases) should receive two doses or the MMR vaccine separated by at least 28-days.
As of January 2018, the Advisory Committee on Immunization Practices (AICP) made a change regarding the MMR vaccination. In the setting of a mumps outbreak, they now recommend those individuals at risk and who are >2 years out from their last MMR vaccination receive a third dose of the MMR vaccine. This recommendation comes following a large study involving university students. Approximately 5000 students who had previously received 2-MMR vaccinations received a third MMR vaccination during an outbreak. There was a significant reduction in the attack rate in those individuals receiving a third dose compared to those who had only received two doses (6.7 vs 14.5 cases per 1000). The effect was more pronounced in those students that had >2 years elapse since their last MMR vaccination.
Reporting:
Reporting varies state by state. Rhode Island DOH mandates reporting within four days of Mumps recognition.
Mumps is not mandatorily reported to the CDC, but often the CDC will be aware and involved in large outbreaks.
Case Outcome
Patient reported that she had previously been completely vaccinated. At the time of her evaluation, two local universities had reported mumps cases. Her presentation occurred prior to the AICP recommendation. Serum IgM and buccal samples were collected. Patient was clinically stable and comfortable with discharge. She was advised to stay at home for 5-days. Her IgM levels were undetectable and the buccal PCR returned as negative. She most likely had a viral adenitis.
Faculty Reviewer: Dr. Kristina McAteer
References
Albrecht, M. (2018). Mumps. In E.L.Baron (Ed.), UpToDate. Retrieved February 9, 2018 from https://www.uptodate.com/contents/mumps.
Center for Disease Control and Prevention. (2017). Mumps. Retrieved from https://www.cdc.gov/mumps/index.html.