1

Pathophysiology of the Pathophysiology of the

GI Tract GI Tract

Ahmed KhattabAhmed Khattab

GastroGastro--intestinal problemsintestinal problems

�� The clinical spectrum of gastroThe clinical spectrum of gastro--intestinal intestinal problems ranges from minor infections problems ranges from minor infections with acute vomiting and diarrhoea, to with acute vomiting and diarrhoea, to functional dyspeptic symptoms and vague functional dyspeptic symptoms and vague undiagnosed abdominal pains through undiagnosed abdominal pains through specific conditions such as peptic ulcers specific conditions such as peptic ulcers and chronic intestinal inflammatory and chronic intestinal inflammatory disorders, to life threatening acute disorders, to life threatening acute abdominal emergencies and cancers. abdominal emergencies and cancers.

Patient consulting rates:Patient consulting rates:

�� OneOne--quarter of consultations are due to GI problems.quarter of consultations are due to GI problems.

�� The most common consultations were for the less The most common consultations were for the less specific conditions such as presumed acute gastrospecific conditions such as presumed acute gastro--intestinal infections, undiagnosed abdominal pain, intestinal infections, undiagnosed abdominal pain, dyspeptic symptoms, functional disorders of the dyspeptic symptoms, functional disorders of the stomach, and uncertain irritable bowel syndrome.stomach, and uncertain irritable bowel syndrome.

�� Life threatening conditions such as cancer and acute Life threatening conditions such as cancer and acute abdominal emergencies are relatively small.abdominal emergencies are relatively small.

�� The nurse must accept that twoThe nurse must accept that two--thirds are these vague thirds are these vague conditions of indefinite nature that have to be managed conditions of indefinite nature that have to be managed nevertheless.nevertheless.

A & PA & P

The Digestive SystemThe Digestive System

Consists of two main groups of organs:Consists of two main groups of organs:

(1) Those of the alimentary canal:(1) Those of the alimentary canal:

�� Mouth, Mouth,

�� Pharynx, Pharynx,

�� Oesophagus, Oesophagus,

�� Stomach, Stomach,

�� Small intestine, Small intestine,

�� Large intestine, including the anus.Large intestine, including the anus.

2. Those of the accessory organs:2. Those of the accessory organs:

�� Teeth, Teeth,

�� Tongue, Tongue,

�� Salivary glands, Salivary glands,

�� Liver, Liver,

�� Gall bladder, Gall bladder,

�� Pancrease.Pancrease.

Figure 24.1

Figure 24.1 The Components of the Digestive SystemFigure 24.1 The Components of the Digestive System

2

�� The alimentary canal is a continuous, The alimentary canal is a continuous, coiled, hallow muscular tube (9 metres “ or coiled, hallow muscular tube (9 metres “ or 30 feet” long) that is opened to the 30 feet” long) that is opened to the external environment at both ends. external environment at both ends.

�� It digests foods and absorbs the digested It digests foods and absorbs the digested materials into the blood.materials into the blood.

Digestive Secretion and Absorption of WaterDigestive Secretion and Absorption of Water

Figure 24.27

Overview of functionsOverview of functions

�� Ingestion:Ingestion: (food intake).(food intake).

�� Propulsion:Propulsion: Movement of food through Movement of food through the tract.the tract.

�� Mechanical digestion:Mechanical digestion: Breaking the food Breaking the food down into smaller fragments.down into smaller fragments.

�� Chemical digestion:Chemical digestion: Food breakdown by Food breakdown by enzymatic action.enzymatic action.

�� Absorption:Absorption: Transport of products of Transport of products of digestion through the intestinal mucosa digestion through the intestinal mucosa into the blood.into the blood.

�� Defecation:Defecation:

Figure 24.4 PeristalsisFigure 24.4 Peristalsis

Figure 24.4

Figure 24.11 The Swallowing ProcessFigure 24.11 The Swallowing Process

Figure 24.11a-h

Our own food breakdown Our own food breakdown

factory!factory!

3

Pathophysiology of GI tract:Pathophysiology of GI tract:

�� 1. Expulsion from G.I. Tract1. Expulsion from G.I. Tract

�� 2. Gastrointestinal inflammation2. Gastrointestinal inflammation

�� 3. Ulceration3. Ulceration

�� 4. G.I. Bleeding4. G.I. Bleeding

�� 5. Obstruction5. Obstruction

�� 6. Malabsorption6. Malabsorption

�� 7. G.I. Tumours7. G.I. Tumours

1. Expulsion from G.I. Tract1. Expulsion from G.I. Tract

�� VomitingVomiting

�� DiarrhoeaDiarrhoea

�� ConstipationConstipation

2. Gastrointestinal inflammation2. Gastrointestinal inflammation

�� i) Oesophagitisi) Oesophagitis

�� ii) Inflammation of the stomach and the intestineii) Inflammation of the stomach and the intestine

�� gastritisgastritis }}

�� enteritisenteritis }}�� gastroenteritisgastroenteritis } } depending on the organs involveddepending on the organs involved

�� enterocolitisenterocolitis }}

�� colitiscolitis }}-- Various irritants of biological or chemical origin can provoke fairly Various irritants of biological or chemical origin can provoke fairly mild inflammations of short duration which will trigger vomiting mild inflammations of short duration which will trigger vomiting

and diarrhoea.and diarrhoea.

-- Damage: minimal.Damage: minimal.-- Healing: rapid.Healing: rapid.

iii) Appendicitis iii) Appendicitis

iv) Peritonitisiv) Peritonitis

�� Caused most commonly by perforation of an Caused most commonly by perforation of an inflammed abdominal organ, often the appendix. inflammed abdominal organ, often the appendix. It may also result from abdominal wounds, It may also result from abdominal wounds, bleeding from GI Tract, or perforation of the bleeding from GI Tract, or perforation of the colon’s wall by colon’s wall by an invading tumour.an invading tumour.

�� Peritonitis often produces the syndrome of acute Peritonitis often produces the syndrome of acute pain onset, fever, and vomiting that is called pain onset, fever, and vomiting that is called acute abdomenacute abdomen..

v) Diverticulitisv) Diverticulitis

�� Diverticular Disease: Pouch formation, Diverticular Disease: Pouch formation, often multiple.often multiple.

�� Diverticula are present in 10% of the Diverticula are present in 10% of the population; 95% of them in the sigmoid population; 95% of them in the sigmoid colon, mainly asymptomatic, and called colon, mainly asymptomatic, and called Diverticulosis.Diverticulosis.

�� Prevalence increases with age; 50% of Prevalence increases with age; 50% of patients over 60 have diverticulae.patients over 60 have diverticulae.

��

Signs and SymptomsSigns and Symptoms

�� If complications happen:If complications happen:

�� Diverticulitis: Sometimes, faecal matter becomes Diverticulitis: Sometimes, faecal matter becomes

impacted in them producing irritation and impacted in them producing irritation and

bacterial infection called bacterial infection called Diverticulitis.Diverticulitis.

�� AbscessAbscess

�� StrictureStricture

�� PerforationPerforation

�� FistulaeFistulae

�� HaemorrhageHaemorrhage

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InvestigationsInvestigations

�� Barium EnemaBarium Enema

�� ColonoscopyColonoscopy

�� CT CT –– best way to show abscessesbest way to show abscesses

vi) Inflammatory bowel disease.vi) Inflammatory bowel disease.

�� NonNon--specific inflammatory bowel diseases are specific inflammatory bowel diseases are

those for which there is no identifiable those for which there is no identifiable

aetiological agent.aetiological agent.

�� Two major forms:Two major forms:

�� Ulcerative colitis “UC”Ulcerative colitis “UC”

�� Crohn’s disease.Crohn’s disease.

�� There is overlap between these two conditions There is overlap between these two conditions

in their clinical features, histological features and in their clinical features, histological features and

radiological features. radiological features.

Small IntestineSmall Intestine The Structure of the Digestive TractThe Structure of the Digestive Tract

Figure 24.3

Structure of the Villi in the Small IntestineStructure of the Villi in the Small IntestineStructures Involved in Absorption of Structures Involved in Absorption of

NutrientsNutrients

Slide

14.26

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Absorptive cells

• Blood capillaries

• Lacteals (specialized lymphatic capillaries)

Figure 14.7b

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AetiopathogenesisAetiopathogenesis

�� Familial: 6Familial: 6--10% of patients affected have one or 10% of patients affected have one or

more relatives with the disease. 10more relatives with the disease. 10--14 time risk 14 time risk

with CD, and 8 times with UC.with CD, and 8 times with UC.

�� GeneticsGenetics

�� DietDiet

�� SmokingSmoking

�� Infective agentsInfective agents

�� ImmunopathogenesisImmunopathogenesis

�� Ulcerative colitis “UC” is always confined to the Ulcerative colitis “UC” is always confined to the

large bowel.large bowel.

�� Crohn’s disease (CD) affects the whole of the GI Crohn’s disease (CD) affects the whole of the GI

tract, from the mouth to the anus, although it tract, from the mouth to the anus, although it

has a tendency to affect the terminal ileum and has a tendency to affect the terminal ileum and

ascending colon.ascending colon.

�� UC usually begins distally affecting the rectum UC usually begins distally affecting the rectum

as proctitis and then spreads proximally to affect as proctitis and then spreads proximally to affect

the whole of the large bowel.the whole of the large bowel.

�� Crohn’s disease typically affects segments Crohn’s disease typically affects segments of the GI tract with areas of diseased of the GI tract with areas of diseased bowel separated by intervening areas of bowel separated by intervening areas of macroscopically (grossly) normal bowel. macroscopically (grossly) normal bowel.

�� The most common area to be affected is The most common area to be affected is the terminal ileum and caecum. The next the terminal ileum and caecum. The next most common area is the colon. Isolated most common area is the colon. Isolated jejunal and ileal Crohn’s disease also jejunal and ileal Crohn’s disease also occurs.occurs.

�� The essential difference between UC and The essential difference between UC and Crohn’s disease is the extent of the Crohn’s disease is the extent of the inflammation. The inflammation of UC is inflammation. The inflammation of UC is confined to the mucosa, whereas in confined to the mucosa, whereas in Crohn’s disease it is transmural and is Crohn’s disease it is transmural and is associated with fissuring, ulcers and associated with fissuring, ulcers and granulomas.granulomas.

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ExtraExtra--intestinal manifestations of intestinal manifestations of

inflammatory bowel disease:inflammatory bowel disease:

�� These include:These include:

�� eye disorderseye disorders

�� joint disordersjoint disorders

�� skin lesionskin lesion

�� aphthous mouth ulcersaphthous mouth ulcers

�� finger clubbingfinger clubbing

�� sclerosing cholangitis etc...sclerosing cholangitis etc...

�� UC can be classified clinically into:UC can be classified clinically into:

�� 1. Mucous colitis1. Mucous colitis

�� 2. Relapsing colitis 2. Relapsing colitis

�� 3. Toxic dilatation3. Toxic dilatation

�� Suspect UC whenever bloody diarrhoea Suspect UC whenever bloody diarrhoea lasts more than 7 days.lasts more than 7 days.

Symptoms:Symptoms:

�� UC:UC:�� Blood and mucus passed per rectum with a formed stool Blood and mucus passed per rectum with a formed stool

suggests that disease is limited to the rectum; if suggests that disease is limited to the rectum; if accompanied by diarrhoea suspect more extensive accompanied by diarrhoea suspect more extensive disease.disease.

�� Other features: Fever, aphthous ulcers, abdominal pain, Other features: Fever, aphthous ulcers, abdominal pain, weight lost, faecal urgency with incontinence.weight lost, faecal urgency with incontinence.

�� General features include: malaise, lethargy, and General features include: malaise, lethargy, and anorexiaanorexia

�� The disease can be mild, moderate or severe, and in The disease can be mild, moderate or severe, and in most patients runs a course of remissions and most patients runs a course of remissions and exacerbations.exacerbations.

�� 10% have persistent chronic symptoms.10% have persistent chronic symptoms.

Clinical features of Crohn’s Clinical features of Crohn’s

disease:disease:

�� Fever, diarrhoea, Cramping abdominal pain, weight loss, Fever, diarrhoea, Cramping abdominal pain, weight loss, and slowing of growth in children. Rectal involvement and slowing of growth in children. Rectal involvement and rectal bleeding is less common than in UC, fever and rectal bleeding is less common than in UC, fever and abdominal pain more so.and abdominal pain more so.

�� Constitutional symptoms of malaise, lethargy, anorexia, Constitutional symptoms of malaise, lethargy, anorexia, nausea, vomiting and low grade fever.nausea, vomiting and low grade fever.

�� In 15% of these patients there are no GI symptoms.In 15% of these patients there are no GI symptoms.�� Anal and perianal lesions are characteristic.Anal and perianal lesions are characteristic.

�� Differentiating UC from Crohn’s is possible in 80% of Differentiating UC from Crohn’s is possible in 80% of patientspatients

3. Ulceration3. Ulceration

�� Peptic ulcer: A breach in the mucosa of Peptic ulcer: A breach in the mucosa of the oesophagus, stomach, duodenum or the oesophagus, stomach, duodenum or jejunum, which extends into the jejunum, which extends into the

submucosa or deeper layers.submucosa or deeper layers.

�� This is in contrast to gastric erosion which This is in contrast to gastric erosion which is confined to mucosa.is confined to mucosa.

�� -- Peptic ulcers may arise throughout the oesophagus, Peptic ulcers may arise throughout the oesophagus, stomach, and small intestine (i.e., those sites stomach, and small intestine (i.e., those sites subjected to the action of the acid and pepsin of the subjected to the action of the acid and pepsin of the gastric juice.gastric juice.

�� -- They are also much less likely to occur in the jejunum They are also much less likely to occur in the jejunum or the ileum, most (98%) arising in the stomach and or the ileum, most (98%) arising in the stomach and duodenum.duodenum.

�� -- They typically arise singly; only 20% of cases involve They typically arise singly; only 20% of cases involve multiple sites.multiple sites.

�� -- The gastric ulcers were thought to be the result of The gastric ulcers were thought to be the result of some compromise in mucosal defence mechanisms.some compromise in mucosal defence mechanisms.

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Main types of peptic ulcer:Main types of peptic ulcer:

�� Acute (stress) ulcerAcute (stress) ulcer

�� Chronic ulcerChronic ulcer

Outline of A & P of StomachOutline of A & P of Stomach

�� Is a JIs a J--shaped, pouchshaped, pouch--like organ.like organ.

�� About 25About 25--30 cm long.30 cm long.

�� It has a capacity of about 1 litre or more.It has a capacity of about 1 litre or more.

�� Its inner lining is marked by thick folds Its inner lining is marked by thick folds (rugae).(rugae).

�� It receives food from the oesophagus, It receives food from the oesophagus, mixes it with gastric juice, initiates the mixes it with gastric juice, initiates the digestion of proteins, carries on limited digestion of proteins, carries on limited absorption, and moves food into the small absorption, and moves food into the small intestine.intestine.

Figure 24.12 The StomachFigure 24.12 The Stomach

Figure 24.12b

Figure 24.13 The Stomach Figure 24.13 The Stomach

LiningLining

Figure 24.13c, d

Regulation of gastric activityRegulation of gastric activity

�� Cephalic phase:Cephalic phase: prepares the stomach to prepares the stomach to receive food. Triggered by the sight, smell, receive food. Triggered by the sight, smell, taste, or thought of food.taste, or thought of food.

�� Gastric phase:Gastric phase: begins with the arrival of begins with the arrival of food in the stomach.food in the stomach.

�� Intestinal phase:Intestinal phase: begins when chyme begins when chyme starts to enter the small intestine, mainly starts to enter the small intestine, mainly inhibitory.inhibitory.

8

�� The lining epithelium of the stomach The lining epithelium of the stomach mucosa is a simple columnar epithelium mucosa is a simple columnar epithelium composed entirely of goblet cells (which composed entirely of goblet cells (which produce protective mucus).produce protective mucus).

�� Other cells in the stomach are:Other cells in the stomach are:

1.1.Mucous neck cells: mucusMucous neck cells: mucus

2.2.Parietal cells: HCl & Intrinsic factorParietal cells: HCl & Intrinsic factor

3.3.Chief cells: Pepsinogen (the inactive from Chief cells: Pepsinogen (the inactive from of pepsin).of pepsin).

4.4.Enteroendocrine cells: Gastrin, Enteroendocrine cells: Gastrin, somatostatin, histamine, etcsomatostatin, histamine, etc

Structure of the Stomach MucosaStructure of the Stomach Mucosa

Slide

14.20b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 14.4b, c

Figure 24.14

The Secretions of Hydrochloric AcidThe Secretions of Hydrochloric Acid

Copyright ©2001 BMJ Publishing Group Ltd.

Calam, J. et al. BMJ 2001;323:980-982

No Caption Found

AetiologyAetiology

-- Hellicobacter pyloriHellicobacter pylori –– N.B.N.B.-- Its location is Its location is relevant relevant

�� -- an acidan acid--resistant, Gramresistant, Gram--negative negative bacillus;bacillus;

�� --Approx in 90% of DUs; and in 70% of Approx in 90% of DUs; and in 70% of GUsGUs

�� -- may be linked with gastric carcinomamay be linked with gastric carcinoma

Copyright ©2001 BMJ Publishing Group Ltd.

Calam, J. et al. BMJ 2001;323:980-982

No Caption Found

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Copyright ©2001 BMJ Publishing Group Ltd.

Calam, J. et al. BMJ 2001;323:980-982

No Caption Found Figure 24.5 The Regulation of Digestive ActivitiesFigure 24.5 The Regulation of Digestive Activities

Figure 24.5

�� -- The effect of NSAIDSThe effect of NSAIDS

�� -- Genetic factorsGenetic factors

�� -- SmokingSmoking

�� -- Alcohol, Spicy food, Stress.Alcohol, Spicy food, Stress.

Causes of duodenal ulcerCauses of duodenal ulcer

�� Helicobacter pyloriHelicobacter pylori antral gastritis antral gastritis

�� NonNon--steroidal antisteroidal anti--inflammatory drugs inflammatory drugs

�� Rare causesRare causes

�� -- Crohn's disease Crohn's disease

�� -- HypergastrinaemiaHypergastrinaemia-- IdiopathicIdiopathic-- Gastrinoma Gastrinoma

�� -- HyperparathyroidismHyperparathyroidism

Clinical FeaturesClinical Features

�� May be little clinical indication.May be little clinical indication.

�� Epigastric pain:Epigastric pain:--

�� -- dull or burningdull or burning

�� --episodic: often wakes patient at nightepisodic: often wakes patient at night

�� -- may be relieved or aggravated by foodmay be relieved or aggravated by food

�� May also c/o May also c/o –– anorexia, vomitinganorexia, vomiting

ComplicationsComplications

�� BleedingBleeding

�� PerforationPerforation

�� Malignancy (GU)Malignancy (GU)

10

OesophagusOesophagus�� Is a muscular, collapsible tube, about 25 cm (10 Is a muscular, collapsible tube, about 25 cm (10

inches) long and about 2 cm in diameter.inches) long and about 2 cm in diameter.

�� It carries solid food and liquids to the stomach.It carries solid food and liquids to the stomach.

�� Lined with a stratified squamous epithelium that Lined with a stratified squamous epithelium that resists abrasion, hot or cold temperatures, and resists abrasion, hot or cold temperatures, and chemicals.chemicals.

�� Regions of muscle in the superior and inferior Regions of muscle in the superior and inferior ends make up the upper and the lower ends make up the upper and the lower oesophageal sphincters.oesophageal sphincters.

�� The lower oesophageal sphincter (LOS) is The lower oesophageal sphincter (LOS) is normally contracted to prevent the backflow of normally contracted to prevent the backflow of materials from the stomach into oesophagusmaterials from the stomach into oesophagus

Symptoms & Signs of oesophageal Symptoms & Signs of oesophageal

disordersdisordersSymptoms:Symptoms:

�� DysphagiaDysphagia

�� Substernal discomfort/heartburnSubsternal discomfort/heartburn

�� Acid regurgitationAcid regurgitation

�� Painful swallowingPainful swallowing

Signs:Signs:

�� Very few signs.Very few signs.

�� May be weight loss as a consequence of May be weight loss as a consequence of dysphagia.dysphagia.

InvestigationsInvestigations

�� Upper GI barium seriesUpper GI barium series

�� IntraIntra--oesophagus pH monitoringoesophagus pH monitoring

�� RadioRadio--nuclear scintigraphynuclear scintigraphy

�� Oesophagoscopy Oesophagoscopy

�� BiopsyBiopsy

�� Oesophageal manometryOesophageal manometry

Hiatus Hernia (HH)Hiatus Hernia (HH)

�� Anatomical abnormality with part of the Anatomical abnormality with part of the stomach in the chest, usually asymtomaticstomach in the chest, usually asymtomatic

�� Herniation of part of the stomach into the Herniation of part of the stomach into the chestchest

�� Sliding HHSliding HH

�� ParaPara--oesophageal or rolling herniaoesophageal or rolling hernia

11

ParaPara--esophageal or rolling esophageal or rolling

herniahernia�� When a small part of the fundus of the stomach rolls up When a small part of the fundus of the stomach rolls up

through the hernia alongside the oesophagus. through the hernia alongside the oesophagus.

�� The sphincter remains below the diaphragm and The sphincter remains below the diaphragm and remains competent. Occasionally a rolling pararemains competent. Occasionally a rolling para--oesophageal hernia will produce severe pain and oesophageal hernia will produce severe pain and require surgical treatment for gastric volvulus or require surgical treatment for gastric volvulus or strangulation. strangulation.

Documenting Reflux:Documenting Reflux:

�� Barium swallow XBarium swallow X--ray is a reliable way of assessing the potential ray is a reliable way of assessing the potential

severity of reflux. It will also show the presence of a hiatus hernia. severity of reflux. It will also show the presence of a hiatus hernia.

GastroGastro--Oesophageal Reflux Oesophageal Reflux

Disease (GORD)Disease (GORD)

�� Definition:Definition:--

�� Where there are symptoms or mucosal Where there are symptoms or mucosal damage (or both) brought about by damage (or both) brought about by exposure of the distal oesophagus to exposure of the distal oesophagus to refluxed gastric acid.refluxed gastric acid.

�� (Reflux : effortless return of gastric (Reflux : effortless return of gastric contents into oesophagus).contents into oesophagus).

Important Reasons to Diagnose and Important Reasons to Diagnose and

Treat GORDTreat GORD

�� Negative impact on healthNegative impact on health--related quality of related quality of lifelife11

�� Risk factor for oesophageal Risk factor for oesophageal adenocarcinomaadenocarcinoma22

1.1. Revicki et al. Am J Med 1998;104:252.Revicki et al. Am J Med 1998;104:252.

2.2. Lagergren et al. N Engl J Med 1999;340:825.Lagergren et al. N Engl J Med 1999;340:825.

�� GastroGastro--oesophageal reflux:oesophageal reflux: Reflux of Reflux of gastric contents which can occur normally gastric contents which can occur normally with no symptoms.with no symptoms.

�� GORD GORD -- patient with reflux who has patient with reflux who has persistent symptoms.persistent symptoms.

�� Reflux oesophagitisReflux oesophagitis –– inflammation of inflammation of the lower oesophagus produced by the lower oesophagus produced by persistent episodes of reflux. Patients may persistent episodes of reflux. Patients may be asymptomatic.be asymptomatic.

12

GORD: AntiGORD: Anti--reflux mechanismsreflux mechanisms

�� The lower oesophageal The lower oesophageal sphincter (LOS) is formed sphincter (LOS) is formed

by the distal 3by the distal 3--4 cm of 4 cm of oesophageal smooth oesophageal smooth

muscle. muscle.

�� It relaxes to allow a bolus It relaxes to allow a bolus to enter the stomach and to enter the stomach and

then rapidly regains its then rapidly regains its normal tone, thereby normal tone, thereby prevents reflux. prevents reflux.

�� It is capable of increasing It is capable of increasing tone in response to rises in tone in response to rises in intraintra--abdominal and abdominal and

intragastric pressures. intragastric pressures.

Peristalsis

Intra-abdominal esophagus

Diaphragm

Lower esophageal sphincter (LES)

Gastric mucosal folds

Unimpeded gastric emptying

The Lower Oesophagus The Lower Oesophagus

Sphincter (LOS)Sphincter (LOS)�� Main barrier to refluxMain barrier to reflux

�� Normally contracted, so pressure raisedNormally contracted, so pressure raised

�� Relaxes on swallowingRelaxes on swallowing

�� Also, transient relaxations at other times.Also, transient relaxations at other times.

Aetiology of GORDAetiology of GORD

�� In reflux: In reflux: ––

�� LOS pressure is too lowLOS pressure is too low

�� OrOr

�� Excessive number of transient relaxationsExcessive number of transient relaxations

Pathogenesis of GORD:Pathogenesis of GORD:

�� The following mechanisms have been The following mechanisms have been implicated:implicated:

�� Transient LOS relaxations.Transient LOS relaxations.

�� Low resting LOS tone which fails to increase Low resting LOS tone which fails to increase when the patient is lying flat, as occurs normally.when the patient is lying flat, as occurs normally.

�� The LOS tone fails to increase when intraThe LOS tone fails to increase when intra--abdominal is increased by tight clothing or abdominal is increased by tight clothing or pregnancy.pregnancy.

�� There is increased oesophageal mucosal There is increased oesophageal mucosal sensitivity to acidsensitivity to acid

�� There is reduced oesophageal clearance There is reduced oesophageal clearance of acid. The reduced acid clearance is of acid. The reduced acid clearance is exacerbated with a HH.exacerbated with a HH.

�� Delayed gastric emptying occurs, which Delayed gastric emptying occurs, which may increase the chance of refluxmay increase the chance of reflux

�� Prolonged episodes of gastroProlonged episodes of gastro--oesophageal reflux which occur at night oesophageal reflux which occur at night and postand post--prandiallyprandially

13

Defective LOS

Motility

Abnormal neural

control of LOS

Transient Lower

Oes. Sphinct. relaxation

GORD

Oesophagitis

Gastric distension

Hiatus Hernia

Clinical Features of GORDClinical Features of GORD

�� -- HeartburnHeartburn

�� -- Oesophagus painOesophagus pain

�� -- Regurgitation into mouthRegurgitation into mouth

�� -- CoughCough

Potential Oral and Laryngopharyngeal Potential Oral and Laryngopharyngeal Signs Associated with GORDSigns Associated with GORD

•• Edema and hyperemia of Edema and hyperemia of

larynxlarynx

•• Vocal cord erythema, Vocal cord erythema,

polyps, granulomas, polyps, granulomas,

ulcersulcers

•• Hyperemia and lymphoid Hyperemia and lymphoid

hyperplasia of posterior hyperplasia of posterior

pharynx pharynx

•• Interarytenyoid changesInterarytenyoid changes

•• Dental erosionDental erosion

•• Subglottic stenosisSubglottic stenosis

•• Laryngeal cancerLaryngeal cancer

Vaezi MF, Hicks DM, Abelson TI, Richter JE. Clin Gastro Hep 2003;1:333Vaezi MF, Hicks DM, Abelson TI, Richter JE. Clin Gastro Hep 2003;1:333--344.344.

Barium SwallowBarium Swallow

�� Useful first diagnostic test for Useful first diagnostic test for patients with dysphagiapatients with dysphagia�� Stricture (location, length)Stricture (location, length)

�� Mass (location, length)Mass (location, length)

�� Hiatal hernia (size, type)Hiatal hernia (size, type)

�� LimitationsLimitations�� Detailed mucosal exam for Detailed mucosal exam for

erosive esophagitis, Barrett’s erosive esophagitis, Barrett’s esophagusesophagus

EndoscopyEndoscopy

�� Indications for endoscopy Indications for endoscopy

�� Alarm symptomsAlarm symptoms

�� Empiric therapy failureEmpiric therapy failure

�� Preoperative evaluationPreoperative evaluation

�� Detection of Barrett’s Detection of Barrett’s

oesophagusoesophagus

Ambulatory 24 hr. pH Ambulatory 24 hr. pH

MonitoringMonitoring

�� Physiologic studyPhysiologic study

�� Quantify reflux in Quantify reflux in

proximal/distal proximal/distal

oesophagusoesophagus

�� % time pH < 4% time pH < 4

�� DeMeester scoreDeMeester score

�� Symptom correlationSymptom correlation

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Ambulatory 24 hr. pH MonitoringAmbulatory 24 hr. pH Monitoring

NormalNormal

GERDGERD

Microbial Populations in the Digestive Tract of Normal Humans

Stomach Jejunum Ileum Colon

Viable

bacteria per gram

0 - 103 0 - 104

105 - 108 1010 - 1012

pH 3.0 6.0-7.0 7.5 6.8-7.3

Wireless, Catheter-Free Oesophageal pH Monitoring

•• Improved patient Improved patient

comfort and acceptancecomfort and acceptance

•• Continued normal work, Continued normal work,

activities and diet studyactivities and diet study

•• Longer reporting periods Longer reporting periods

possible (48 hours)possible (48 hours)

•• Maintain constant probe Maintain constant probe

position relative to SCJposition relative to SCJ

Potential AdvantagesPotential Advantages

Oesophageal ManometryOesophageal Manometry

�� Assess LES pressure, Assess LES pressure,

location and relaxationlocation and relaxation

�� Assist placement of 24 Assist placement of 24

hr. pH catheterhr. pH catheter

�� Assess peristalsisAssess peristalsis

�� Prior to antireflux Prior to antireflux surgery surgery

Limited role in Limited role in

GORDGORD

Peptic StricturePeptic Stricture

Barium SwallowBarium Swallow EndoscopyEndoscopy

TTS Balloon Dilation of a Peptic StrictureTTS Balloon Dilation of a Peptic Stricture

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Barrett’s EsophagusBarrett’s Esophagus Oesophageal CancerOesophageal Cancer

Barium SwallowBarium Swallow EndoscopyEndoscopy

Barrett’s oesophagusBarrett’s oesophagus

�� Presence of intestinal metaplastic Presence of intestinal metaplastic columnar epithelium which has replaced columnar epithelium which has replaced squamous epithelium as a consequence of squamous epithelium as a consequence of acid reflux.acid reflux.

Barrett’s oesophagusBarrett’s oesophagus

�� This is thought to occur from longThis is thought to occur from long--standing standing reflux.reflux.

�� It consists of columnar epithelium with It consists of columnar epithelium with intestinal metaplasia extending upwards intestinal metaplasia extending upwards into the lower oesophagus replacing into the lower oesophagus replacing normal squamous epithelium.normal squamous epithelium.

�� Seen in 20% of patients undergoing Seen in 20% of patients undergoing endoscopy for gastroendoscopy for gastro--oesophageal reflux oesophageal reflux diseasedisease

�� Barrett’s oesophagus is preBarrett’s oesophagus is pre--malignant for malignant for adenocarcinoma.adenocarcinoma.

�� An indocarmine spray down the An indocarmine spray down the endoscope can detect intestinal endoscope can detect intestinal metaplasia and possibly dysplasia.metaplasia and possibly dysplasia.

�� Dysplasia is patchy and biopsies from all 4 Dysplasia is patchy and biopsies from all 4 quadrants (every 2 cm) of the Barrett’s quadrants (every 2 cm) of the Barrett’s segment must be performed.segment must be performed.

GORD: ComplicationsGORD: Complications

Barrett’s EsophagusBarrett’s Esophagus

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AchalasiaAchalasia

�� A disease characterized by aperistalsis in A disease characterized by aperistalsis in the body of the oesophagus and failure of the body of the oesophagus and failure of relaxation of the lower oesophagus relaxation of the lower oesophagus sphincter on initiation of swallowing .sphincter on initiation of swallowing .

Achalasia: DiagnosisAchalasia: Diagnosis

Achalasia: DiagnosisAchalasia: Diagnosis Aetiology & PathologyAetiology & Pathology

�� Unknown (idiopathic).Unknown (idiopathic).

�� A similar clinical picture is seen in Chagas’A similar clinical picture is seen in Chagas’

�� Disease (American trypanosomiasis).Disease (American trypanosomiasis).

�� Degenerative lesions are found in the Degenerative lesions are found in the vagus as well as a decrease in ganglionic vagus as well as a decrease in ganglionic cells in the nerves of the oesophageal cells in the nerves of the oesophageal wall.wall.

4. G.I. Bleeding4. G.I. Bleeding

�� -- Haematemesis (vomiting of blood), is typically Haematemesis (vomiting of blood), is typically associated with gastric or oesophageal bleeding.associated with gastric or oesophageal bleeding.

�� -- Melena: Dark tarMelena: Dark tar--like colour stool due to blood lost like colour stool due to blood lost directly into the small intestine or reaching it from gastric directly into the small intestine or reaching it from gastric lesion. Bleeding peptic ulcers are the most common lesion. Bleeding peptic ulcers are the most common cause of such blood loss.cause of such blood loss.

�� -- Bleeding from colon’s wall usually appears bright red in Bleeding from colon’s wall usually appears bright red in the stool.the stool.

�� -- LongLong--term bleeding of smaller quantities of blood may term bleeding of smaller quantities of blood may not be detected in the stool. The presence of a lownot be detected in the stool. The presence of a low--grade anaemia may be evidence of the slow bleeding grade anaemia may be evidence of the slow bleeding and confirmation by detecting occult blood. and confirmation by detecting occult blood.

Cholelithiasis (Gallstones)Cholelithiasis (Gallstones)

�� The Gall bladder:The Gall bladder:

�� The gall bladder rests in a recess on the The gall bladder rests in a recess on the inferior surface of the right liver lobe.inferior surface of the right liver lobe.

�� Bile leaves the liver through several bile Bile leaves the liver through several bile ducts that fuse to form large hepatic duct, ducts that fuse to form large hepatic duct, which will fuse with the cystic duct which will fuse with the cystic duct (draining the gall bladder) to form the (draining the gall bladder) to form the common bile duct. common bile duct.

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�� The gall bladder is a thinThe gall bladder is a thin--walled, green walled, green muscular sac.muscular sac.

�� Approximately 10 cm long.Approximately 10 cm long.

�� It stores bile that is not immediately It stores bile that is not immediately needed for digestion and concentrates it needed for digestion and concentrates it by absorbing some of its water and ions.by absorbing some of its water and ions.

Cholelithiasis (Gallstones)Cholelithiasis (Gallstones)

�� Aetiology:Aetiology:

�� Uncertain, but…….Uncertain, but…….

�� -- metabolic?metabolic?

�� -- bile stasis?bile stasis?

�� -- infective component?infective component?

Figure 24.19b, c

The Anatomy of the LiverThe Anatomy of the LiverThe Gall BladderThe Gall Bladder

Slide

14.23b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 14.6

Clinical FeaturesClinical Features

1. 80% of patients with gallstones are 1. 80% of patients with gallstones are asymptomaticasymptomatic

2. Inflammatory:2. Inflammatory:--

�� -- acute cholecystitisacute cholecystitis

�� -- acute pancreatitisacute pancreatitis

�� ((-- cholangitis)cholangitis)

3. Motility:3. Motility:--

�� Biliary colicBiliary colic

�� Obstructive jaundiceObstructive jaundice

�� CholangitisCholangitis

4. Other problems: mucocele, empyema, fistula 4. Other problems: mucocele, empyema, fistula formationformation

Vomiting (Emesis)Vomiting (Emesis)

�� The forceful, sudden expulsion from the The forceful, sudden expulsion from the mouth of the gastric, and possibly mouth of the gastric, and possibly duodenal, contents.duodenal, contents.

�� Often preceded by:Often preceded by:-- nausea; anorexianausea; anorexia

�� Nausea Nausea -- Salivary flow; Sympathetic Salivary flow; Sympathetic activity.activity.

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MechanismMechanism

�� Epiglottis closes off larynx;Epiglottis closes off larynx;

�� Soft palate rises to close off nasopharynx;Soft palate rises to close off nasopharynx;

�� Pyloric sphincter relaxes (Pyloric sphincter relaxes (�� duodenal duodenal contents enter stomach);contents enter stomach);

�� Diaphragm, abdominal muscles & pyloric Diaphragm, abdominal muscles & pyloric sphincter contract strongly;sphincter contract strongly;

�� Lower oesophageal sphincter relaxesLower oesophageal sphincter relaxes

CTZCTZ

Cerebellum Cerebellum Vomiting Centre ChemicalsVomiting Centre Chemicals

Inner Ear Inner Ear Sensory StimuliSensory StimuliGag reflexGag reflex

Vagal inputVagal input

CN V, VII, IX, XCN V, VII, IX, X Spinal motor neurons Spinal motor neurons supplying diaphragm andsupplying diaphragm andabdominal musclesabdominal muscles

Diarrhoea:Diarrhoea:

�� WorldWorld--wide, diarrhoeal diseases are second only to cardiovascular wide, diarrhoeal diseases are second only to cardiovascular diseases as a cause of death. In the UK, diarrhoea is the most diseases as a cause of death. In the UK, diarrhoea is the most common illness after the common cold, and account for about 10% common illness after the common cold, and account for about 10% of all visits to GPs, and incur substantial time lost from school and of all visits to GPs, and incur substantial time lost from school and work.work.

�� Many diarrhoeal illnesses are acute, mild to moderate in severity, of Many diarrhoeal illnesses are acute, mild to moderate in severity, of brief duration and selfbrief duration and self--limiting. In such cases, individuals do not limiting. In such cases, individuals do not seek the advice of a nurse or a doctor and usually deal with the seek the advice of a nurse or a doctor and usually deal with the illness themselves using overillness themselves using over--thethe--counter remedies, by modifying counter remedies, by modifying their diet, or by doing nothing.their diet, or by doing nothing.

�� Medical help is usually sought when diarrhoea is more severe, lasts Medical help is usually sought when diarrhoea is more severe, lasts for more than a few days, is accompanied by fever or rectal for more than a few days, is accompanied by fever or rectal bleeding.bleeding.

�� There are many diagnostic tests, many of which are costly , timeThere are many diagnostic tests, many of which are costly , time--consuming and invasive. It is therefore essential to have a consuming and invasive. It is therefore essential to have a systematic approach such that an accurate diagnosis can be systematic approach such that an accurate diagnosis can be reached without subjecting the patient to too many unnecessary reached without subjecting the patient to too many unnecessary investigations. investigations.

�� The term “diarrhoea” means different things to The term “diarrhoea” means different things to different people.different people.

�� Decrease in stool consistency; Decrease in stool consistency;

�� and an increase in its fluidity.and an increase in its fluidity.

�� Increased frequency (more than 3 stools/day)Increased frequency (more than 3 stools/day)

�� Quantity 200Quantity 200--250 gm/day ??250 gm/day ??

�� Acute diarrhoea is usually defined as diarrhoea Acute diarrhoea is usually defined as diarrhoea that lasts for 2that lasts for 2--3 weeks.3 weeks.

�� Chronic diarrhoea is any diarrhoeal illness that Chronic diarrhoea is any diarrhoeal illness that lasts for more than 3 weeks.lasts for more than 3 weeks.

Clinical approach to diarrhoea:Clinical approach to diarrhoea:

�� There are many ways to classify There are many ways to classify diarrhoea:diarrhoea:

�� duration of diarrhoeal disease ( acute duration of diarrhoeal disease ( acute vsvschronic)chronic)

�� risk group (travellers to developing risk group (travellers to developing countries, patients with AIDS, hospital incountries, patients with AIDS, hospital in--patients)patients)

�� specific features of the diarrhoea (bloody specific features of the diarrhoea (bloody vsvs fatty fatty vs vs watery).watery).

History:History:

�� Determine what the patient means by diarrhoea.Determine what the patient means by diarrhoea.

�� The diarrhoea should be characterised with regard to:The diarrhoea should be characterised with regard to:�� onset, duration, frequency, estimation of volume, characteristics of onset, duration, frequency, estimation of volume, characteristics of

stool (e.g., floating, foul smell, blood, mucus, pus), relationship to stool (e.g., floating, foul smell, blood, mucus, pus), relationship to meals/fasting and diurnal variation.meals/fasting and diurnal variation.

�� Specific enquiry should be made about faecal incontinence.Specific enquiry should be made about faecal incontinence.�� A careful dietary, drug and travel history should be taken.A careful dietary, drug and travel history should be taken.

�� Enquiry should be made regarding unusual diets or changes in diet.Enquiry should be made regarding unusual diets or changes in diet.

�� The patient should be questioned about poorly absorbed The patient should be questioned about poorly absorbed carbohydrates (e.g., sorbitol). carbohydrates (e.g., sorbitol).

�� A detailed social history should be taken.A detailed social history should be taken.

�� Bloody diarrhoea and abdominal pain suggest mainly an Bloody diarrhoea and abdominal pain suggest mainly an inflammatory processinflammatory process

�� Bulky, greasy, foulBulky, greasy, foul--smelling stool is highly suggestive of smelling stool is highly suggestive of steatorrhoea (fat malabsorption).steatorrhoea (fat malabsorption).

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�� Nocturnal diarrhoea, particularly with faecal Nocturnal diarrhoea, particularly with faecal incontinence, should always prompt a search for organic incontinence, should always prompt a search for organic disease.disease.

�� The patient should be questioned about associated The patient should be questioned about associated symptoms such as abdominal pain or cramps, flatulence, symptoms such as abdominal pain or cramps, flatulence, bloating, fever, weight loss and tenesmus.bloating, fever, weight loss and tenesmus.

�� The influence of psychological stress should be explored The influence of psychological stress should be explored in a sensitive manner (? irritable bowel syndrome).in a sensitive manner (? irritable bowel syndrome).

�� History of diabetesHistory of diabetes

�� History of radiation therapyHistory of radiation therapy�� Previous abdominal surgeryPrevious abdominal surgery

�� A family history of diarrhoeal disease is uncommon. It A family history of diarrhoeal disease is uncommon. It raises the possibility of coeliac disease.raises the possibility of coeliac disease.

Physical examination:Physical examination:

�� Signs of dehydration (dry mouth, decreased skin turgor, Signs of dehydration (dry mouth, decreased skin turgor, tachycardia, orthostatic hypotension).tachycardia, orthostatic hypotension).

�� Tenderness of the abdomen suggest an underlying Tenderness of the abdomen suggest an underlying inflammatory condition.inflammatory condition.

�� Abdominal mass (Crohn’s disease, diverticular disease, Abdominal mass (Crohn’s disease, diverticular disease, malignancy).malignancy).

�� DistensionDistension

�� The presence and the quality of bowel sounds.The presence and the quality of bowel sounds.

�� Digital examination of the rectum and inspection of the Digital examination of the rectum and inspection of the perianal area allows detection of occult or gross faecal perianal area allows detection of occult or gross faecal blood (infectious, inflammatory, or neoplastic).blood (infectious, inflammatory, or neoplastic).

�� Enlarged lymph nodes may suggest malignancy.Enlarged lymph nodes may suggest malignancy.

Diagnosis:Diagnosis:

�� Acute diarrhoea are usually brief (< 5 Acute diarrhoea are usually brief (< 5 days) and selfdays) and self--limiting, and are not limiting, and are not associated with systemic upset.associated with systemic upset.

�� Causes (Table)Causes (Table)

�� Chronic diarrhoea:Chronic diarrhoea:

�� Almost all patients with chronic diarrhoea Almost all patients with chronic diarrhoea need investigation after the history and need investigation after the history and physical examination.physical examination.

�� Causes (Table)Causes (Table)

Constipation:Constipation:

�� Defined as a bowel frequency of fewer than Defined as a bowel frequency of fewer than three per week or the need to strain more than three per week or the need to strain more than 25% of the time during defecation.25% of the time during defecation.

�� In Western societies, 10In Western societies, 10--20% of adults believe 20% of adults believe themselves to be constipated, and a similar themselves to be constipated, and a similar proportion regularly take laxatives.proportion regularly take laxatives.

�� Other symptoms that patients regard as Other symptoms that patients regard as constipation include the passage of hard stools, constipation include the passage of hard stools, painful or incomplete evacuation, and even painful or incomplete evacuation, and even abdominal discomfort.abdominal discomfort.

Successful management Successful management

depends on:depends on:

�� defining the patient’s symptomsdefining the patient’s symptoms

�� characterising the abnormality of defecationcharacterising the abnormality of defecation

�� excluding secondary causesexcluding secondary causes

�� Long standing mild constipation in younger Long standing mild constipation in younger patients can usually be managed patients can usually be managed symptomatically. Investigations to exclude an symptomatically. Investigations to exclude an obstructive cause are required in:obstructive cause are required in:

�� Older patientsOlder patients

�� Patients with rectal bleedingPatients with rectal bleeding

�� Patients with symptoms of recent onsetPatients with symptoms of recent onset

Causes of constipation:Causes of constipation:

�� In most patients, the aetiology (the cause) is In most patients, the aetiology (the cause) is

unknown.unknown.

�� Abnormal neurological controlAbnormal neurological control

�� Psychological factorsPsychological factors

�� ObstructionObstruction

�� DrugsDrugs

�� Spinal or pelvic nerve injuriesSpinal or pelvic nerve injuries

�� Other causes (depression, Parkinson’s disease, Other causes (depression, Parkinson’s disease,

hypothyroidism)hypothyroidism)