Oesophagus

Question 1

List some DDx for dysphagia?

Answer 1

Neuromuscular (difficulty with solids and liquid, intermittent)
o Primary- achalasia (diffuse oesophageal spasm, myenteric plexus defect), myasthenia gravis
o Secondary- scleroderma, myotonic dysphagia, bulbar palsy, pharyngeal paralysis

Mechanical (solids NOT liquids, constant)
(Note: normal lumen 2-3cm, dysphagia if <1.3cm)
o Intraluminal- foreign body
o Luminal-
- Oesophageal adenocarcinoma
- Strictures (progressive): GORD, medication-induced (e.g. NSAID), chemo/radiation
- Pharyngeal pouch: neck bulge
- Oesophageal webs: extension of normal mucosal tissue (usually anterior post-cricoid)
- Osophageal rings (Schatzki rings): concentric smooth extension of oesophageal tissue
o Extraluminal:
- Enlarged aorta or LA
- Mediastinal mass: lymphadenopathy, retrosternal goitre, bronchial tumour

Functional dysplasia: dysphagia in absence of other major motor, structural or mucosal abnormalities

Question 2

What imaging should be ordered to investigate dysphagia?

Answer 2

1. Barium swallow test- indicated in likely oesophageal lesion or strictures, prior to endoscopy (reduce perforation risk)
   - Scleroderma findings: dilated lower oesophagus, difficulty emptying oesophageal contents into stomach
2. Endoscopy-
   - Look for fibrosis, sclerosis, mass, lesion
   - Visualize or biopsy any dysplastic region
   - See if LES open
   - Stent obstructions
3. Oesophageal manometry- thin, pressure-sensitive tube placed in whole oesophageal length, pt sips water and device assesses peristaltic movements
   - Scleroderma: reduced peristalsis in lower 2/3 (smooth m) and loss of LES tone
   - Achalasia: LES unaffected
   - Diffuse oesophageal spasm: uncoordinated contraction

Question 3

Describe scleroderma?

Answer 3

Scleroderma is an autoimmune disease

• characterised by a triad of autoimmunity, non-inflammatory vasculopathy and collagen deposition with fibrosis
• Clinical: skin sclerosis (puffy, taught, no wrinkles, fingertip pitting), sclerosis of renal/GIT/CVS, oesophageal dysphagia (90%), spontaneous scarring BV disease, varying inflammation (assoc w overactive immune system), reflux
• Epi: 75% F, age 30-50yo
• Types: systemic (anti-SCL-70 Ab) and localised (CREST syndrome)

Question 4

Describe the pathogenesis of dysphagia in scleroderma?

Answer 4

⇒ Scleroderma (increased collagen depositing and fibrosis) -> small BV damage
⇒ Intramural neuronal damage -> smooth muscle atrophy (lower 2/3) -> loss of tone (lower 2/3)
⇒ Loss of peristalsis -> hypomotility, weakness, LES incompetence

Question 5

Name the normal sites of oesophageal constriction?

Answer 5

4 sites:

1) C6: cricopharyngeal sphincter (15cm from incisor)
2) T4: aortic arch (25cm from incisor)
3) T5-6: L main bronchus (28cm from incisor)
4) T10: oesophageal hiatus (40cm from incisor)

Note: enlarged LA can also constrict oesophagus

Question 6

Describe the vasculature of the oesophagus?

Answer 6

Upper 1/3 (cricoid cartilage to aortic arch level)
o Arterial: Inferior thyroid artery
o Venous: inferior thyroid vein

Middle 1/3
o Arterial: Oesophageal branches of aorta
o Venous: Azygos vein

Lower 1/3
o Arterial: L gastric artery
o Venous: L gastric vein, inferior phrenic vein

Question 7

Describe the innervation of the oesophagus?

Answer 7

Upper part:
o Parasympathetic- recurrent laryngeal nerve (branch of vagus n)
o Sympathetic- cell bodies in middle cervical ganglion (running in on inferior thyroid arteries)
Lower part:
o Parasympathetic- vagus nerve -> forms anterior and posterior oesophageal plexus
o Sympathetic- sympathetic trunks and greater splanchnic nerve
Entire oesophagus:
o Motor supply to muscle (striated and smooth)- vagus nerve (directly or via recurrent laryngeal branch)
o Mucosal mucus glands (secretomotor fibers)- vagus
o Inferior ganglion sensory fibred- vagus

Question 8

Discuss the layers of the oesophagus wall?

Answer 8

Layers:

• Stratified squamous epithelium
• Inner circular muscle- continuous w cricopharyngeus muscle
• Outer longitudinal muscle- attached to midline ride on cricoid cartilage and to arytenoid cartilages

Muscle changes: upper 1/3 skeletal, middle 1/3 mixed, lower 1/3 smooth muscle

Question 9

Describe the neuromuscular physiology of swallowing?

Answer 9

1. Voluntary oral phase:
   ⇒ Food moved by tongue (CN12) and mastication muscles (CNV3) up and back towards pharynx
   ⇒ Pharynx sensory receptors activated
   ⇒ Vagus and glossopharyngeal n.s. transmit to medullary swallowing centre -> initiates swallowing reflex
   ⇒ Cerebellum controls output of motor nuclei CN V3, 7, 12
2. Involuntary pharyngeal phase:
   ⇒ Soft palate elevated to seal off nasopharynx
   ⇒ CN9 provides sensory feedback, pharyngeal plexus and CNV2 provide motor feedback
   ⇒ Trachea closed off to protect airway:
   - Hyoid bone raised, epiglottis falls back
   - Vocal cords move to midline
   ⇒ UES relaxes -> initates primary peristaltic wave
3. Oesophageal phase
   ⇒ Vagal motor neurons signal enteric nerves in oesophagus -> initiates peristaltic wave
   ⇒ Food bolus propelled down oesophagus
   ⇒ LED opens and stomach relaxes in to receive food