Mumps
Summary
Mumps is an acute viral infection caused by a Paramyxovirus, characterised by painful swelling of the parotid glands ("Epidemic Parotitis"). Before the introduction of the MMR vaccine, it was a common childhood illness. Today, outbreaks occur in unvaccinated communities or young adults (university students) with waning immunity. While the parotitis is self-limiting, Mumps is significant due to its complications: Orchitis (in post-pubertal males), Meningitis (usually aseptic), Pancreatitis, and Deafness. Diagnosis is confirmed by Oral Fluid PCR. It is a Notifiable Disease. [1,2]
Key Facts
- Transmission: Droplet spread (coughing/sneezing) and direct contact with saliva.
- Infectivity: Most infectious from 2 days before to 5 days after the onset of swelling.
- Orchitis: Occurs in 20-30% of post-pubertal males. Can lead to testicular atrophy (50%) but sterility is rare (usually unilateral).
- Amylase: Serum amylase is universally raised (Salivary + Pancreatic origin).
Clinical Pearls
The Sour Taste Test: The pain of Mumps parotitis is classically worsened by salivation. Giving the child lemon juice or a sour sweet causes intense pain in the angle of the jaw.
Loss of the Jaw Angle: Parotid swelling obliterates the angle of the mandible. If you can clearly feel the sharp corner of the jaw bone, the swelling is likely lymphadenopathy (which sits below the jaw), not parotitis.
Orchitis Timing: Testicular swelling typically starts 1 week after the parotitis. Warn patients to return if this happens.
MMR Failure: Two doses of MMR are ~88% effective. Breakthrough cases can occur (often milder), but the vast majority of cases in outbreaks are unvaccinated.
Incidence
- Drastically reduced by vaccination.
- Outbreaks: Occur cyclically (every 3-5 years) particularly in universities/colleges.
Risk Factors
- No MMR vaccination.
- Close contact (schools/dorms).
Virology
- Agent: Mumps virus (RNA Paramyxovirus).
- Entry: Respiratory epithelium -> Local replication -> Viraemia.
- Tropism: High affinity for glandular tissue (Salivary, Testes, Pancreas, Ovaries) and CNS (Meninges).
History
Other Manifestations
Head and Neck
- Parotid Swelling: Diffuse, tender, boggy swelling anterior and inferior to the ear.
- Assessment:
- Ear lobe pushed upwards and outwards.
- Angle of mandible obscured.
- Stensen's Duct (inside cheek opposite 2nd upper molar) may be red/swollen.
Systemic
- Genitals: Check for scrotal swelling/tenderness (Orchitis).
- Neurology: Check for meningism.
- Abdomen: Epigastric tenderness.
Microbiology (The Gold Standard)
Mumps is a Notifiable Disease. Testing is required for surveillance.
- Oral Fluid Swab (PCR): Viro-cult swab / Oracol swab rubbed on the gums/cheek. Detects viral RNA. Highest yield in first week.
- Serology (IgM): Blood test. Can be used if swab negative or late presentation (>7 days).
Bloods
- Amylase: Elevated (Salivary/Pancreatic).
- Inflammatory Markers: CRP/WBC usually normal or mildly elevated (Viral).
Management Algorithm
SUSPECTED MUMPS
(Tender Parotitis)
↓
ISOLATE PATIENT
(5 days from onset)
↓
NOTIFY PUBLIC HEALTH
+ SWAB (Oral Fluid)
↓
┌───────────┴───────────┐
UNCOMPLICATED COMPLICATED
(Parotitis only) (Orchitis/Meningitis)
↓ ↓
SUPPORTIVE ASSESS SEVERITY
(Analgesia, Fluids, (Pain control? Fluid
Rest) intake?)
↓ ↓
MILD SEVERE
(Home) (Admit)
1. General Measures
- Isolation: Exclude from school/work for 5 days after onset of swelling.
- Hydration: Key, but avoid acidic drinks (stimulate painful salivation).
- Analgesia: Paracetamol/Ibuprofen.
2. Management of Orchitis
- Supportive: Bed rest, Scrotal support (tight underwear), Ice packs.
- Analgesia: Start NSAIDs early.
- Follow up: Reassurance re: fertility. Atrophy may occur months later.
3. Management of Meningitis
- Usually benign and self-limiting.
- Admission for lumbar puncture to exclude bacterial meningitis if diagnosis uncertain.
- Supportive care.
4. Public Health
- Notify: Health Protection Team (HPT).
- Contacts: Check MMR status. Offer vaccine if unimmunised (though unlikely to prevent current infection if already incubating).
- Orchitis: 20-30% of post-pubertal males.
- Meningitis: Aseptic. 15%.
- Sensorineural Hearing Loss: Unilateral. Permanent in 1 in 20,000 cases. Transient in 4%.
- Pancreatitis: Usually mild.
- Spontaneous Abortion: If infection in first trimester (27% risk). No congenital malformations associated (unlike Rubella).
- Parotitis: Resolves in 7-10 days.
- Orchitis: Symptoms resolve in 1-2 weeks. Fertility usually preserved.
- Immunity: Infection confers lifelong immunity.
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Mumps | PHE / UKHSA | Oral fluid swab for all suspected cases. Exclude for 5 days. |
| Immunisation | Green Book | MMR at 1 year and 3y4m. Catch up effectively at any age. |
Landmark Knowledge
1. MMR Controversy (Wakefield, 1998)
- Event: Fraudulent paper linking MMR to autism.
- Impact: Massive drop in vaccination rates in early 2000s.
- Result: Resurgence of Mumps (and Measles) outbreaks in university students who missed doses as children (the "Wakefield Cohort").
What is Mumps?
It is a viral infection that causes the salivary glands in the cheeks to swell up, giving a "hamster" appearance.
Is it serious?
Usually, it is just painful and annoying. However, in teenage boys and men, it can spread to the testicles (Orchitis), causing severe pain and swelling. It can also cause meningitis (headache).
Can it make men sterile?
This is a huge worry for patients. The answer is: Rarely. While it can shrink the testicle (atrophy), it is very rare for it to cause complete infertility, especially as it usually only affects one side.
When can I go back to school?
You are infectious for 5 days after the swelling started. You must stay home until then to stop spreading it.
Primary Sources
- Public Health England. Mumps: guidance, data and analysis. Gov.uk.
- Hviid A, et al. Mumps. Lancet. 2008;371:932-944. PMID: 18342688.
- Davis NF, et al. The increasing incidence of mumps orchitis: a comprehensive review. BJU Int. 2010;105:1060-1065.
Common Exam Questions
- Paediatrics: "Child with swollen cheeks, ear pushed out. Diagnosis?"
- Answer: Mumps Parotitis.
- Urology: "20yo male, 1 week after 'flu-like illness/swollen face', presents with swollen testis. Diagnosis?"
- Answer: Mumps Orchitis.
- Infectious Disease: "Transmission period?"
- Answer: 2 days before to 5 days after swelling.
- ENT: "Unilateral hearing loss after viral illness. Cause?"
- Answer: Mumps.
Viva Points
- MMR Vaccine: Type? Live Attenuated. Contraindicated in pregnancy/immunocompromised.
- Aseptic Meningitis: What does CSF show? Lymphocytosis, Raised Protein, Normal Glucose. (Bacteria not seen).
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.