Upper GI tract Flashcards
Describe the anatomical contributions to the lower oesophageal sphincter
3-4 cm distal oesophagus within abdomen
Diaphragm surrounds LOS
An intact phrenoesophageal ligament - The upper limb attaches the esophagus to the superior surface of the diaphragm and the lower limb attaches the cardia region of the stomach to the inferior surface of the diaphragm at the cardiac notch of stomach. The ligament allows independent movement of the diaphragm and esophagus during respiration and swallowing.
Angle of His - acts as a barrier against reflux
Describe the stages of swallowing
Stage 0: Oral phase - Chewing & saliva prepare bolus. Both oesophageal sphincters constricted.
Stage 1: Pharyngeal phase - Pharyngeal musculature guides food bolus towards oesophagus. Both oesophageal sphincters open.
Stage 2: Upper oesophageal phase - Upper sphincter closes. Superior circular muscle rings contract & inferior rings dilate. Sequential contractions of longitudinal muscle.
Stage 3: Lower oesophageal phase - Lower sphincter closes as food passes through
How is the motility of the oesophagus measured?
Manometry pressure measurements - tube passed through nose down oesophagus to record pressure of the contractions, exposing whether contractility is normal or not.
What are normal pressure measurements in the oesophagus?
Peristaltic waves ~ 40 mmHg
LOS resting pressure ~ 20 mmHg
↓<5 mmHg during receptive relaxation - this is mediated by inhibitory noncholinergic nonadrenergic (NCNA) neurons of myenteric plexus
What causes functional disorders of the oesophagus?
Absence of a stricture. Caused by either abnormal oesophageal contraction (hypermotility, hypomotility, disordered coordination) or failure of protective mechanisms for reflux (gastrooesophageal reflux disease).
What is dysphagia?
Dysphagia is difficulty in swallowing. Localisation important - depends whether distal or the cricopharyngeal sphincter. Types of dysphagia:
For solids or fluids
Intermittent or progressive
Precise or vague in appreciation
What is odynophagia, regurgitation and reflux?
Odynophagia is pain on swallowing
Regurgitation refers to return of oesophageal contents from above an obstruction. May be functional or mechanical.
Reflux is passive return of gastroduodenal contents to the mouth.
What is achalasia?
Refers to hypermotility. Occurs due to loss of ganglion cells in Aurebach’s myenteric plexus in LOS wall which leads to decreased activity of inhibitory NCNA neurones.
What is the proposed pathophysiology of achalasia?
An environmental trigger such as a chronic infectious insult combined with a genetic predisposition and genetic factors (mutations and SNIPs ALADIN, NOS, IL-10 etc) lead to increase in non autoimmune inflammatory infiltrates (increase in Th1, Tregs, Bregs, pDCregs). This leads to extracellular turnover, wound repair mechanisms activating and fibrosis. Conversely, increase in immune cells can trigger an immunosuppressive response leading to loss of immunological tolerance, loss of neurons and eventually humoral response (antinuclear antibodies, antimyenteric antibodies). Causes myenteric neuronal abnormalities, autoimmune myenteric plexitis, vasculitis, absence of peristalsis and decreased relaxation of LOS.
What is secondary achalasia?
Caused by other disorders which mimic the symptoms of primary achalasia. These diseases cause oesophageal motor abnormalities: Chagas’ Disease, Protozoa infection, Amyloid/Sarcoma/Eosinophilic Oesophagitis.
What happens in achalasia?
Increased resting pressure of LOS, almost 80mmHg. Receptive relaxation sets in late & is too weak - during reflex phase pressure in LOS is markedly ↑er than stomach. Swallowed food collects in oesophagus causing ↑ pressure throughout with dilation of the oesophagus. Propogation of peristaltic waves cease.
Describe disease course of achalasia
Has insidious onset - symptoms for years prior to seeking help. If untreated, progressive oesophageal dilatation of oesophagus occurs. Causes a 28-fold increase in risk of oesophageal cancer.
What is a treatment option for achalasia?
Pneumatic dilatation. Stent with balloon inserted and balloon then inflated, opening up LOS. PD weakens LOS by circumferential stretching & in some cases, tearing of its muscle fibres. Efficacy of PD— 71 - 90% of patients respond initially but many patients subsequently relapse.
What are surgical treatment options for achalasia?
Heller’s Myotomy - A continuous myotomy performed for 6 cm on the oesophagus & 3 cm onto the stomach.
Dor fundoplication – anterior fundus folded over oesophagus and sutured to right side of myotomy
What are the risks of gastric surgery?
Oesophageal & gastric perforation (10 – 16%)
Division of vagus nerve – rare
Splenic injury – 1 – 5%
What is scleroderma?
An autoimmune disease referring to hypomobility in its early stages due to neuronal defects - atrophy of smooth muscle of oesophagus occurs. Peristalsis in the distal portion ultimately ceases altogether. Decreased resting pressure of LOS means GORD develops and is often associated with CREST syndrome.
What is the treatment for scleroderma?
Exclude organic obstruction
Improve force of peristalsis with prokinetics (cisapride)
Once peristaltic failure occurs → usually irreversible
What does corkscrew oesophagus cause?
Disordered coordination due to diffuse oesophageal spasm. Incoordinate contractions causes dysphagia & chest pain. Pressures of 400-500 mmHg can occur. Marked hypertrophy of circular muscle.
What is treatment for corkscrew oesophagus?
May respond to forceful PD of cardia but results not as predictable as achalasia.
Describe anatomy of oesophageal perforations
There are 3 areas of anatomical constrictions: Cricopharyngeal constriction, aortic and bronchial constriction, diaphragmatic and sphincter constriction. However, pathological constrictions can be caused by cancer, foreign body, physiological dysfunction.
Describe aetiology of oesophageal perforation
Iatrogenic (OGD) >50% Spontaneous (Boerhaave’s) - 15% Foreign body - 12% Trauma - 9% Intraoperative - 2% Malignant - 1%
