- Microbiology & Etiology
- Gram-negative rod, oxidase (+).
- Curved, comma or S-shaped (seagull wing appearance).
- Thermophilic: Grows best at 42°C (Campy-fire burns hot).
- Motile (polar flagella).
- Transmission
- Fecal-oral route.
- Major reservoir: Intestinal tract of animals (esp. poultry).
- Risk factors: Ingestion of undercooked poultry, unpasteurized milk, contact with infected animals (puppies/kittens).
- Pathophysiology
- Organism invades the mucosa of the colon and destroys epithelial cells.
- Produces cytolethal distending toxin → cell cycle arrest and DNA damage.
- Inflammation leads to bloody, inflammatory diarrhea.
- Clinical Features
- Prodrome: High fever, headache, myalgias, and malaise (12–24 hours before GI symptoms).
- GI Symptoms:
- Abrupt onset of severe, crampy abdominal pain (often mimics acute appendicitis or pseudoappendicitis). c
- Tenesmus.
- Diarrhea: Initially watery, progressing to bloody/mucoid stools (up to 10+ episodes/day).
- Diagnostics
- Stool Culture: Gold standard.
- Requires selective media (Skirrow agar or Campy-BAP) containing antibiotics (vancomycin, polymyxin B, trimethoprim).
- Incubated at 42°C under microaerophilic conditions.
- Stool leukocyte/lactoferrin (+).
- Differential
- Acute Appendicitis: Diff by absence of prodromal diarrhea/fever prior to pain; US or CT abdomen shows appendiceal inflammation without colitis. c
- Complications
- Guillain-Barré Syndrome (GBS):
- Ascending paralysis/weakness.
- Mechanism: Molecular mimicry. Antibodies against C. jejuni lipooligosaccharides cross-react with gangliosides (e.g., GM1) in peripheral nerve myelin/axons.
- Reactive Arthritis (Reiter syndrome):
- Triad: Urethritis, Uveitis, Arthritis (“Can’t see, can’t pee, can’t climb a tree”).
- Assoc. with HLA-B27.
- Treatment
- Supportive Care: Fluid and electrolyte replacement (mainstay).
- Antibiotics (reserved for severe/prolonged cases):
- First-line: Azithromycin (macrolides).
- Alternative: Fluoroquinolones (though resistance is increasing).