6.1 Upper GI Flashcards
Where does the oesophagus begin?
C5
At what vertebral level dies the oesophagus pass through the diaphragm at the oesophageal hiatus?
T10
What is the oesophagus?
A muscular tube connecting the pharynx to the cardia of the stomach, behaving as a conduit for food
What type of muscle comprises the upper cervical oesophagus?
Skeletal muscle
What type of muscle comprises the middle and upper thoracic oesophagus?
Skeletal and smooth muscle
What type of muscle comprises the lower thoracic oesophagus?
Smooth muscle
In what state does the lower oesophageal sphincter tonically exists in?
Exists in a constricted state
What reflex causes the LOS to open?
Receptive relaxation, facilitating the passage of substrate into the cardia of the stomach
What diaphragmatic structure surrounds the LOW?
The left and right crus of the diaphragm
During inspiration what happens to the LOS?
The diaphragmatic sling would constrict the oesophagus forming a functional sphincter that prevents gastric reflex when intra-abdominal pressure rises
Which ligament attaches the oesophagus to the diaphragm?
Intact phrenoesphageal ligament
The upper limb of the phrenoesophageal ligament resides where?
Superior to the surface of the diaphgram
Where does the lower limb of the phrenoesophgeal ligament reside?
Cardia region of the stomach
What is the function of the phrenoesophageal ligament?
Allows the independent movement of the diaphragm an oesophagus during respiration and swallowing
What is the acute angle between the cardia, at the entrance of the stomach and the oesophagus?
Angle of His
What is the purpose of the angle of His?
Prevents reflux of duodenal bile, enzymes and gastric acid from entering the oesophagus
What are the four stages of swallowing?
Stage 0: Chewing, and saliva prepares bolus
Stage I: Pharyngeal phase
Stage II: Upper oesophageal phase
Stage III: Lower oesophageal phase
In what state are the UOS and lOS in during chewing?
Both are constricted
What is the pharyngeal phase?
The pharyngeal musculature guides food bolus towards oesophagus
UOS opens reflexly
In what state are both the UOS and LOS in during the pharyngeal phase?
- Upper oesophagus sphincter opens reflexly.
* LOS opened by vasovagal reflex (receptive relaxation).
What is the upper oesophageal phase?
- Upper sphincter closes
- Superior circular muscle rings contract and inferior rings dilate promoting peristaltic movements.
- Sequential contractions of longitudinal muscles (act antagonistically, contracting ahead of the bolus.
What state is the UOS during the upper oesophageal phase?
Closed
What happens during the lower oesophageal phase?
Lower sphincter closes as food passes through
What is the resting pressure of the LOS?
20mmHg
What happens to the LOS pressure during receptive relaxation?
Pressure decreases to <5mmHg, opening the sphincter, to allow substrate to pass through into the stomach
Which neurones mediate receptive relaxation of the LOS?
Inhibitory noncholinergic noradrenergic NCNA neurones of the myenteric plexus within the muscularis layer
How is receptive relaxation of the LOS mediated?
Receptive relaxation is induced by the stimulation of NCNA fibres, opening the LOS, by inhibiting contraction
What is dysphagia?
Difficulty in swallowing
What is odynophagia?
Pain on swallowing
What is regurgitation?
Refers to the return of oesophageal contents from above an obstruction (functional or mechanical).
What is reflux?
Passive return of gastroduodenal contents to the mouth.
What terms describes hypomotility of the oesophagus?
Achalasia
What is achalasia?
Achalasia refers to the absence of ganglion cells within the Auerbach’s myenteric plexus in the LOS wall.
• Loss of NCNA inhibitory neurones therefore receptive relaxation to facilitate the movement of bolus into the cardia of the stomach is impaired – the LOS remains in the constricted state
Which type of neurones are absent in achalsia?
Inhibitory NCNA neurones
What happens to the LOS in achalasia?
Remains in a constricted state due to a loss of receptive relaxation
What are the oesophageal motor abnormalities that resemble achalasia (secondary(?
Chaga’s disease
Protozoa infection
Amyloid/sarcoma/eosinophillic oesophagitis
Which autoimmune cells are recruited causing a loss of immunological tolerance and autoimmune inflammation?
Th1 cells release cytokines
Which types of antibodies stimulates neuronal apoptosis in achalasia?
Antimyenteric antibodies – loss of NCNA inhibitory neurones
What happens to the resting pressure of the LOS in hypermotility?
The resting pressure increases due to loss of inhibitory NCNA neurones, maintains an excessively constricted state
- This causes delayed receptive relaxation that is inadequate (reflux phase pressure is LOS is markedly higher than the stomach)
What is the main consequence of hyper-motility of the oesophagus?
Swallowed food accumulates within the oesophagus, increasing pressure throughout, leading to oesophageal dilation
Peristaltic waves ceases
What happens to peristaltic waves in hyper-motility of the oesophagus?
Ceases
What type of onset does achalasia have?
Insidious onset, with persistent symptoms prior to treatment
How is oesophageal dilation detected?
Upon barium swallow
What happens to the risk of developing oesophageal cancer in patients with achalasia?
Increases 28-fold (0.34% annual incidence)
What are the presentations of achalasia?
Weight loss, oesophagitis, and risk of pneumonia, due to aspiration into the lungs
What is pneumatic dilatation?
A wire connected with a deflated balloon descending through the LOS, and is inflated, for the treatment of achalasia
• Circumferential stretching (+tearing of muscle fibres) – reduces the resting pressure of the LOS and promotes relaxation of the stricture.
What is the main non-surgical treatment recommended for achalasia?
Pneumatic dilatation
What are the surgical interventions for achalasia?
Heller’s myotomy
and
Dor fundolipication
Peroral endoscopic myotomy (POEM)
What is Heller’s myotomy?
Heller’s myotomy: A continuous myotomy performed for 6cm on the oesophagus & 3cm onto the stomach. Laparoscopic scissors to cut the muscularis layer, exposing the mucosal layer such that the fundus is wrapped around the exposed mucosa.
• Dor fundoplication – anterior fundus folded over oesophagus and sutured to the right side of myotomy.
What are the risks associated with Heller’s myotomy?
- Oesophageal and gastric perforation (10-16%)
- Division of vagus nerve – rare
- Splenic injury (1-5%).
What is peroral endoscopic myotomy (POEM)?
- Endoscope enters into the dilated oesophagus, whereby a mucosal incision is made.
- Formation of a submucosal tunnel, accessing the muscularis layer
- Myotomy
- Closure of mucosal incision.
What is scleroderma?
An autoimmune disorder characterised by fibroblast activation, producing elevated amounts of collagen
Hypomotility in early stages due to neuronal defects - atrophy of oesophageal smooth muscle
Disruption of peristalsis in the distal portion of the oesophagus
Decreased resting pressure f the LOS - this potentates the likeliness of developing GORD (CREST syndrome is associated), as the LOS i uncontracted
What is the greatest risk associated with scleroderma?
Gastro-oesophageal reflux