What a final-year mumps topic covers

1. Virology, transmission, incubation, infectivity, epidemiology
2. Clinical presentation
   • Typical parotitis and prodrome
   • Atypical/subclinical illness
3. Complications by organ system
   • CNS, testes/ovaries, pancreas, hearing, pregnancy
4. Differential diagnosis of parotid swelling
5. Diagnosis
   • RT-PCR, buccal swab technique/timing, serology, public-health notification
6. Management
   • Supportive care, analgesia, hydration, complication-specific management
7. Infection prevention and public health
   • Isolation period, contact management, outbreak precautions
8. Vaccination
   • MMR schedule, contraindications, outbreak third-dose indications
9. Exam and bedside approach
   • High-yield viva questions, red flags, common pitfalls

High-level clinical framework

Mumps: final-year medical student guide

1. Definition and why it still matters

Mumps is an acute infection with an enveloped, negative-sense single-stranded RNA paramyxovirus, causing epidemic parotitis and potentially aseptic meningitis, orchitis, pancreatitis, and sensorineural hearing loss.

2. Virology

3. Epidemiology and transmission

Transmission

• Respiratory droplets
• Saliva and direct close contact
• Contaminated respiratory secretions or fomites less commonly

Incubation period

• Average: 16-18 days
• Range: 12-25 days

Infectious period

• 2 days before parotitis begins
• Through 5 days after onset of parotitis

Important epidemiological facts

• In the pre-vaccine era, most people acquired mumps during childhood.
• Two-dose MMR programmes have reduced incidence dramatically.
• Cases can occur in people with two documented MMR doses.
• Breakthrough outbreaks do not mean MMR is ineffective. Mumps vaccine effectiveness is lower than the measles component, immunity can decline with time, and close, repeated exposure can overcome partial immunity.

4. Clinical presentation

A. Typical mumps

Prodrome

• Low-grade fever
• Malaise and fatigue
• Headache
• Myalgia
• Anorexia
• Sore throat or nonspecific upper-respiratory symptoms

Parotitis

• Painful swelling and tenderness of one or both parotid glands
• Usually begins on one side, then becomes bilateral in many patients
• May involve the submandibular or sublingual glands
• Swelling peaks over 1-3 days and usually settles over approximately 7-10 days
• Ear lobule is pushed upward and outward
• The angle of the mandible may be obscured
• Pain may increase with chewing or acidic foods due to salivary stimulation

5. Complications

A. Mumps orchitis

• Primarily postpubertal males.
• Reported in approximately 15-35% of postpubertal males with mumps.
• Usually unilateral, but may be bilateral in roughly one-quarter of cases.

• Usually occurs around 1 week after parotitis.
• Can precede parotitis or occur without it.

• Fever
• Acute testicular pain, swelling, erythema, and tenderness
• Scrotal edema
• Possible epididymal involvement

• Pain and swelling usually improve in about a week, but tenderness can last longer.
• Testicular atrophy may develop.
• Permanent infertility is uncommon, although impaired spermatogenesis and subfertility may occur, especially with bilateral disease.

• Bed rest
• Scrotal elevation/support
• Cold packs
• NSAID or paracetamol
• Exclude torsion and bacterial epididymo-orchitis
• No routine antiviral or corticosteroid treatment

B. Oophoritis and mastitis

C. Aseptic meningitis

• Headache
• Fever
• Neck stiffness
• Vomiting
• Photophobia
• Drowsiness

D. Encephalitis

• Altered mental state
• Seizures
• Focal neurological deficit
• Aphasia
• Reduced consciousness
• Marked fever or deterioration

E. Hearing loss

• Usually sudden, unilateral, and sensorineural
• May be transient
• May have tinnitus, vertigo, or other vestibular symptoms
• Permanent, particularly bilateral, deafness is rare but important

F. Pancreatitis

• Epigastric pain radiating to the back
• Persistent vomiting
• Abdominal tenderness
• Raised lipase

G. Pregnancy

6. Differential diagnosis of parotitis

7. Diagnosis

A. When to suspect mumps

• Acute unilateral or bilateral parotitis or other salivary-gland swelling
• A compatible prodrome
• Orchitis, oophoritis, aseptic meningitis, pancreatitis, or sudden hearing loss without another clear cause
• Exposure to a case or an outbreak setting
• Incomplete vaccination history

B. First actions in suspected mumps

1. Isolate using droplet precautions
2. Notify local infection-control and public-health teams
3. Obtain a focused history and examination for complications
4. Collect diagnostic specimens promptly
5. Do not wait for results before instituting isolation

C. Laboratory confirmation

Preferred test: rRT-PCR

• Obtain a buccal swab for real-time reverse-transcription PCR.
• Massage the parotid gland for about 30 seconds before swabbing to improve yield.
• Collect as early as possible after parotitis begins.
• Ideally collect in the first 0-3 days and within 10 days of onset.

Serology

• Serum mumps IgM can support the diagnosis.
• IgM is more likely detectable several days after symptom onset.
• In vaccinated patients, IgM may be absent, delayed, or transient.
• A negative IgM is therefore not sufficient to exclude mumps.
• IgG positivity mainly reflects past infection or vaccination and is not, by itself, proof of acute disease.

Other samples

• Urine, CSF, and blood may occasionally be tested in specific clinical contexts.
• In a patient with CNS disease, send CSF for routine cell count, glucose, protein, bacterial studies, and a viral workup guided by local protocols.

In suspected mumps, take a buccal swab for rRT-PCR as soon as possible and serum for IgM. In a vaccinated patient, negative IgM or PCR does not reliably exclude mumps if clinical suspicion remains high.

8. Management

A. Uncomplicated mumps

• Oral fluids and nutrition
• Rest
• Paracetamol or NSAIDs for pain and fever, if appropriate
• Soft diet
• Avoid acidic foods and drinks if they worsen salivary pain
• Warm or cool compresses to swollen glands according to comfort
• Safety-net advice and review if complications develop

B. Admit or urgently assess if there is

• Altered consciousness, seizures, focal neurology, or severe headache
• Meningism or suspected encephalitis
• Severe dehydration or inability to drink
• Severe abdominal pain or suspected pancreatitis
• Acute painful swollen testis, especially if torsion cannot be excluded
• Sudden hearing loss or severe vertigo
• Immunocompromise, severe comorbidity, or diagnostic uncertainty

9. Infection prevention and public health

Isolation

• Keep the patient away from school, university, work, and healthcare duties during this period.
• Encourage cough hygiene and hand hygiene.
• Avoid sharing utensils, drinks, towels, or close face-to-face contact.
• In hospital, use a single room if feasible and droplet precautions.

Notification

Contacts

• Check evidence of immunity and MMR status.
• Bring those without adequate MMR vaccination up to date.
• MMR given after exposure does not reliably prevent mumps from that exposure, but it provides future protection.
• In an outbreak, public-health authorities may recommend a third MMR dose for people at increased risk who have already received two doses.
• There is no standard immune-globulin post-exposure prophylaxis for mumps.

10. Vaccination

Routine vaccination

• First dose at 12-15 months
• Second dose at 4-6 years

Vaccine effectiveness

Who should not receive MMR?

• Pregnancy
• Severe immunodeficiency
• Previous anaphylaxis to a vaccine component or a prior dose

Third dose

Bedside approach to a patient with suspected mumps

History

• Onset and progression of swelling
• Unilateral versus bilateral involvement
• Fever, headache, malaise, myalgia
• Pain when chewing or with acidic foods
• Contacts with parotitis or known mumps
• University, school, shared accommodation, team sport, military, prison, or outbreak exposure
• Travel
• MMR doses and dates, if known
• Testicular pain or swelling
• Pelvic pain or breast pain
• Headache, neck stiffness, photophobia, drowsiness, seizures
• Hearing loss, tinnitus, vertigo
• Abdominal pain and vomiting
• Immunocompromise and pregnancy status

Examination

• Vital signs and hydration assessment
• Inspection and palpation of parotid, submandibular, and cervical areas
• Oral examination, including Stensen duct for pus
• Otoscopy if ear symptoms
• Full neurological examination if headache or altered sensorium
• Abdominal examination
• Genital examination if genital symptoms, with urgent torsion assessment where appropriate
• Hearing assessment at the bedside if auditory symptoms

Investigations

• Buccal swab rRT-PCR
• Serum mumps IgM
• FBC, U&E, CRP only if clinically indicated, not to diagnose mumps
• Lipase if pancreatitis is suspected
• Urinalysis and STI testing if epididymo-orchitis is in the differential
• Urgent scrotal ultrasound if torsion is possible
• Lumbar puncture and neuroimaging guided by CNS presentation

High-yield viva questions

What is the most common clinical manifestation?

When is mumps infectious?

What is the best confirmatory test?

How do you improve buccal-swab yield?

Does a negative IgM rule out mumps?

What is the most important complication in postpubertal males?

What is the emergency differential diagnosis of mumps orchitis?

What should you do immediately for suspected mumps in hospital?

Is there an antiviral treatment?

Can vaccinated people get mumps?

Memory aid

• Meningitis / meningoencephalitis
• Unilateral sensorineural hearing loss
• Male orchitis
• Pancreatitis
• Salivary-gland swelling
• Sterility is rare, but testicular atrophy/subfertility can occur

Suspect mumps in acute parotitis even in vaccinated people. Isolate and notify early. Confirm with early buccal-swab rRT-PCR, do not over-rely on IgM, provide supportive treatment, and actively look for orchitis, CNS disease, pancreatitis, and hearing loss.

Pathophysiology of meningococcal infection

1. The bacterium evades innate immune killing and multiplies rapidly in blood
2. Its lipooligosaccharide endotoxin causes an overwhelming inflammatory and endothelial injury response

The whole process in one flow

Respiratory-droplet acquisition
        ↓
Nasopharyngeal colonization
        ↓
Mucosal invasion and entry into blood
        ↓
Survival in blood: capsule + complement evasion
        ↓
High-grade bacteremia and release of LOS endotoxin
        ↓
Cytokine storm + endothelial injury
        ↓
Capillary leak + vasodilation + myocardial dysfunction + DIC
        ↓
Septic shock, purpura fulminans, multiorgan failure
        ↓
In some patients: crossing blood-meningeal barrier
        ↓
Meningitis: intense subarachnoid inflammation, cerebral edema, raised ICP

1. Acquisition and colonization of the nasopharynx

Initial attachment

• Type IV pili: the key initial adhesins
• Opa and Opc proteins: allow closer adherence to epithelial receptors
• Other adhesins such as NadA

• Attachment to epithelial microvilli
• Formation of bacterial microcolonies
• "Twitching motility", allowing movement across the epithelial surface
• Subsequent invasion of the mucosa

Factors that promote invasion

• Recent viral upper-respiratory infection
• Cigarette smoke exposure
• Dry, cold conditions
• Crowding, such as in dormitories, military barracks, or mass gatherings
• Young age, especially after maternal antibody protection wanes
• Lack of protective bactericidal antibody

2. Survival in the bloodstream: why the capsule matters

• Complement activation
• C3b opsonization
• Phagocytosis by neutrophils and macrophages
• Membrane attack complex formation, particularly C5-C9

A. Polysaccharide capsule

• Inhibits opsonization
• Reduces antibody-mediated phagocytosis
• Reduces complement-mediated killing
• Allows persistence and rapid multiplication in the bloodstream

B. Factor H binding and complement evasion

Why terminal complement deficiency is high risk

• Terminal complement deficiency: C5-C9
• Properdin deficiency
• C3 deficiency
• Use of complement inhibitors, especially eculizumab or ravulizumab
• Functional or anatomical asplenia
• Antibody deficiency

3. Meningococcemia: endotoxin is the central event

LOS versus LPS

Lipid A + core polysaccharide + O antigen

4. How LOS produces septic shock

Step 1: Innate immune recognition

• LPS-binding protein
• CD14
• MD-2
• TLR4 on monocytes/macrophages, neutrophils, and endothelial cells

Step 2: Cytokine and inflammatory mediator release

• TNF-alpha
• IL-1 beta
• IL-6
• IL-8
• Other chemokines
• Nitric oxide
• Complement activation products
• Procoagulant mediators

Step 3: Endothelial dysfunction

• Increased vascular permeability
• Capillary leak
• Loss of intravascular volume
• Tissue edema
• Leukocyte adhesion and vascular inflammation
• Microvascular thrombosis
• Impaired tissue perfusion

Step 4: Vasodilatory shock

• Systemic vasodilation
• Reduced systemic vascular resistance
• Hypotension
• Maldistribution of blood flow

Step 5: Coagulation activation and DIC

• Widespread microthrombi
• Consumption of platelets and clotting factors
• Disseminated intravascular coagulation, DIC
• Simultaneous thrombosis and bleeding
• Ischemic injury to skin, kidneys, adrenals, and limbs

5. Why the rash is petechial or purpuric

Endothelial injury + thrombocytopenia + DIC + dermal microvascular thrombosis

• Small, non-blanching petechiae

• Larger purpura
• Ecchymoses
• Purpura fulminans
• Skin necrosis
• Acral ischemia and limb loss

6. Waterhouse-Friderichsen syndrome

• Acute adrenal failure
• Severe hypotension refractory to usual resuscitation
• Hypoglycemia and electrolyte disturbance may occur
• Rapid cardiovascular collapse

7. How it causes meningitis

• Choroid plexus
• Meningeal microvascular endothelium
• Disruption/opening of intercellular junctions

1. Bacteria multiply because CSF has limited antibody and complement activity.
2. Bacterial LOS and cell-wall components stimulate macrophages, endothelial cells, and recruited neutrophils.
3. Cytokines increase blood-brain barrier permeability.
4. Neutrophilic inflammation produces a purulent exudate.
5. Cerebral edema and impaired CSF circulation develop.

• Fever
• Headache
• Neck stiffness
• Photophobia
• Vomiting
• Altered consciousness
• Seizures, focal deficits, or coma in severe disease

Mechanisms of brain injury in meningococcal meningitis

8. Why some people develop sepsis, some meningitis, and some both

• Degree and speed of bloodstream multiplication
• Amount of LOS released
• Host inflammatory response
• Host antibody and complement status
• Bacterial strain virulence
• Whether and when bacteria cross the blood-meningeal barrier

Exam-focused summary

Neisseria meningitidis first colonizes the nasopharynx using type IV pili and adhesins. It invades the bloodstream through the mucosa and evades complement and phagocytosis using its polysaccharide capsule, factor H-binding proteins, and LOS sialylation. Rapid bacterial proliferation releases LOS endotoxin, which activates TLR4-mediated cytokine release. This causes endothelial injury, capillary leak, vasodilation, myocardial dysfunction, coagulation activation, DIC, petechiae, purpura fulminans, and septic shock. The organism can cross the blood-meningeal barrier and multiply in CSF, where intense inflammation causes purulent meningitis, cerebral edema, raised intracranial pressure, and possible neurological injury.

• Pili: attach to nasopharynx
• Adhesins: invade epithelium/endothelium
• Capsule: avoids complement and phagocytosis
• Endotoxin, LOS: cytokine storm, shock, DIC
• Leptomeningeal invasion: meningitis and cerebral edema

Meningococcal infection: brief pathophysiology

1. Colonization
   It first attaches to the nasopharynx using type IV pili. Most people remain asymptomatic carriers.
2. Bloodstream invasion
   In a few people, it crosses the mucosa and enters blood. Its polysaccharide capsule protects it from phagocytosis and complement killing.
3. Meningococcemia and shock
   The organism multiplies rapidly and releases LOS endotoxin. LOS activates TLR4, causing release of TNF-alpha, IL-1, IL-6, and other inflammatory mediators.
4. Endothelial injury and DIC
   The cytokine response causes:
   • Vasodilation and capillary leak → hypotension/shock
   • Endothelial injury
   • Coagulation activation → DIC
   • Skin microthrombi and bleeding → non-blanching petechiae/purpura
5. Meningitis
   Bacteria can cross the blood-brain barrier into CSF. Inflammation in the subarachnoid space causes meningeal irritation, cerebral edema, raised intracranial pressure, and sometimes seizures or coma.

Pili help colonization, capsule allows survival in blood, and LOS endotoxin causes cytokine storm, shock, DIC, purpura, and potentially meningitis.