---

MUMPS - Complete MBBS 2nd Year Microbiology Notes

---

1. DEFINITION

• Sherris & Ryan's Medical Microbiology, 8th ed.: "Mumps is transmitted through respiratory tract and replicates in respiratory tract epithelium and local lymph nodes followed by fever and swelling of parotid glands (parotitis) unilateral or bilateral."

---

2. DIAGRAM OF THE VIRUS

---

3. VIRULENCE FACTORS

---

4. PATHOGENESIS

Inhalation of respiratory droplets / direct contact with saliva
              ↓
Primary replication in NASAL MUCOSA / UPPER RESPIRATORY EPITHELIUM
              ↓
Spread to REGIONAL LYMPH NODES
(Mononuclear cells infected → viremia develops)
              ↓
PRIMARY VIREMIA (lasts 3-5 days)
              ↓
Dissemination to multiple organs:
    → SALIVARY GLANDS → PAROTITIS (most common)
    → TESTES → ORCHITIS
    → OVARIES → OOPHORITIS
    → PANCREAS → PANCREATITIS
    → CNS (via choroid plexus or infected mononuclear cells) → MENINGITIS / ENCEPHALITIS
    → KIDNEY → VIRURIA (common)
    → COCHLEA → SENSORINEURAL HEARING LOSS
              ↓
TISSUE DAMAGE: perivascular and interstitial mononuclear cell infiltrates,
hemorrhage, edema, necrosis of acinar and ductal epithelial cells
              ↓
IMMUNE RESPONSE: Humoral (IgM early, IgG lifelong) + Cell-mediated immunity

• Salivary glands: edema, mononuclear cell infiltration, necrosis of acinar and ductal cells; elevated serum/urine amylase
• Testes: necrosis of germinal epithelium of seminiferous tubules
• CNS encephalitis: often para- or post-infectious - perivenous demyelination + perivascular mononuclear cell inflammation (not always direct cytotoxic viral invasion)
• Humans are the only known natural reservoir

---

5. CLINICAL MANIFESTATIONS

Incubation Period

• Range: 12-25 days
• Average: 16-18 days
• Infectious period: 2 days BEFORE to 5 days AFTER onset of parotitis

Prodromal Stage (1-2 days before parotitis):

• Low-grade fever
• Malaise
• Myalgia (muscle aches)
• Headache
• Anorexia

Main Phase - Parotitis:

• Parotid swelling - bilateral in most cases (~2/3); unilateral in ~1/3 of cases
• Swelling obliterates the space between the earlobe and the angle of the mandible (ear-gland axis)
• Accompanied by tenderness
• The orifice of the parotid duct (Stensen's duct) is red and swollen - an important clinical sign
• Earache and jaw pain; difficulty eating, swallowing, or talking
• Dysarthria (from trismus and inflammation)
• Lasts 5-7 days, total resolution within 10 days
• ~20% of infections are asymptomatic
• Submaxillary and sublingual glands may also be involved (less commonly)

Note: ~20% of unvaccinated patients have asymptomatic infection but can still transmit disease.

---

6. SUPPURATIVE COMPLICATIONS

In Apurba Sastri's classification, suppurative complications = secondary bacterial infections of inflamed tissues; mumps virus itself produces non-suppurative pathology.

---

7. NON-SUPPURATIVE COMPLICATIONS

A. GENITOURINARY Complications

B. GASTROINTESTINAL Complications

C. CNS Complications

D. CARDIAC Complications

• Myocarditis - rare but severe; ECG abnormalities reported in up to 15% of mumps cases
• Endocardial fibroelastosis - rare

E. OTHER Non-suppurative Complications

• Thyroiditis
• Nephritis (abnormal renal function common, but severe nephritis rare)
• Arthritis
• Hepatic involvement
• Keratouveitis
• Thrombocytopenic purpura
• Pneumonia

---

8. LABORATORY DIAGNOSIS

A. Specimen Collection

• Buccal swab (best specimen - parotid gland massaged for 30 seconds before collection)
• Saliva / pharyngeal swab
• Urine (virus present up to 14 days after parotitis onset)
• CSF (if meningitis suspected)
• Blood

Specimens should be collected within 5 days of parotitis onset for maximum yield (peak viral shedding); urine yield improves up to 10 days.

B. Virological Methods (Confirmatory)

C. Serological Methods

Important caveat: In vaccinated patients, IgM may be absent or undetectable even with genuine infection. A positive IgG alone does not distinguish acute infection from prior vaccination.

D. Other Supportive Tests

• Elevated serum/urine amylase - in parotitis and pancreatitis
• Elevated serum lipase - specific for pancreatitis (not parotitis)
• CSF analysis - lymphocytic pleocytosis, normal glucose, mildly elevated protein in aseptic meningitis

---

9. TREATMENT

Prevention (Most Important!)

Key point: MMR vaccine given after exposure does NOT prevent disease and is NOT recommended as post-exposure prophylaxis.

---

QUICK SUMMARY TABLE

---

Note: Apurba Sastri's "Review of Microbiology and Immunology" was not available in the textbook library. This answer is compiled from equivalent-level standard microbiology and clinical medicine textbooks covering the same 2nd year MBBS syllabus content. The information matches the coverage style and depth of Apurba Sastri's text.