Gastrointestinal conditions Signs, causes And Differentials Flashcards
What are the causes of metabolic acidosis?
Diabetic ketoacidosis (ketones produced are acidic)
Lactic acidosis (increased acid production)
Renal failure (reduced acid secretion)
Chronic diarrhoea (bicarbonate loss)
What are the causes of metabolic alkalosis?
Increased alkali ingestion
Vomiting
Potassium depletion
What is irritable bowel syndrome?
What are the subtypes?
A chronic condition primarily manifesting as a syndrome of colicky abdominal pain, bloating and altered bowel habit.
Types:
Diarrhoea predominant
Constipation predominant
What are the signs of irritable bowel syndrome?
Presentation is variable
- Colicky abdominal pain anywhere in abdomen, can be severe pain
(colic = pain that abruptly comes and goes with peristaltic motions) - Abdominal bloating
- Constipation, diarrhoea or alternating between the two
- Faecal incontinence
- Urgency
- Exaggerated gastro-colonic reflex (every time you eat, you defaecate)
- Anxiety about eating
- Bloating (can go up 2 dress sizes)
Extra-intestinal symptoms:
- Nausea
- Thigh pain
- Back ache
- Lethargy
- Urinary symptoms
- Gynaecological symptoms - commonly dyspareunia
What are the differentials for acute abdominal pain?
Peritonitis
Ruptured AAA
Hepatic/pancreatic/biliary: Cholecystitis Common bile duct stones Cholangitis Acute pancreatitis
GI: Bowel obstruction Acute mesenteric ischemia Gastro/duodenal ulcer Diverticulitis Gastroenteritis Constipation IBD - chrons disease or ulcerative colitis Strangulated hernia Adhesions Appendicitis
Renal:
Pyelonephritis
Renal colic
Hepatic:
Hepatic abscess
Hepatitis
Reproductive: Ectopic pregnancy Testicular torsion Ovarian cyst rupture or torsion or haemorrhage Pelvic inflammatory disease Pregnancy
Cardiac:
MI
Haematological: Sickle cell crisis DKA Addisonian crisis Hypercalcemia
Which two patient groups are most at risk of mesenteric ischemia?
The elderly - CAD means thrombosis is likely
Those in AF - blood stasis means embolism is likely
What is mesenteric ischemia?
The blockage or occlusion of bowel arteries, often the superior mesenteric artery, nearly always the small intestines are the location.
What are the causes of mesenteric ischemia?
Superior mesenteric artery thrombosis (35% of cases)
Superior mesenteric artery embolism (35% of cases)
Non-occlusive disease (poor cardiac output)
Mesenteric vein thrombosis
Trauma
Vasculitis
Radiotherapy
Strangulation - herniated bowel or volvulus (twisted bowel)
What are the cardinal symptoms of acute mesenteric ischemia?
Often asymptomatic - they look well, pain is the only real symptom
Acute, severe abdominal pain
Pain is in the centre of the abdomen or right iliac fossa
Constant pain
Rapid hypovolaemia and shock
What are the cardinal symptoms of chronic mesenteric ischemia?
Severe colicky abdominal pain (-peristalsis against ischemic area)
Post-prandial pain (-pain upon increasing)
Weight loss (-due to chronic pain on eating)
Potentially plus: N and V Abdominal bruit PR bleeding Malabsorption
What is the major cause of chronic mesenteric ischemia?
Coronary artery disease (CAD)
By which pathophysiological mechanisms does H. Pylori cause increased acid production?
It tends to infect the antrum of the stomach, and therefore causes inflammation to the local cells:
- Inflammation increases gastrin production (more acid production)
- Inflammation suppresses D cell action (less somatostatin, less parietal cell inhibition)
- Inflammation directly induces increased parasympathetic stimulation (increases acid production)
(There is also evidence that the bacteria feeds on mucosal surfactant)
What are the two main causes of gastric ulcers?
NSAIDs
H.Pylori infection
What are the symptoms of a gastric (peptic) ulcer?
Burning/gnawing pain in your upper abdomen, that can radiate to the back or inferiorly
Pain is usually related to eating
Epigastric tenderness
Potentially: Indigestion Heartburn Bloating after fatty foods Nausea and vomiting Early satiety Weight loss Diarrhoea GI bleeds Anaemia symptoms (fatigue,pallor)
What is a gastroduodenal/peptic ulcer?
Lesions in the lining of the gastrointestinal mucosa due to the action of pepsin and stomach acid.
What are the differentials for a burning pain in the epigastrium?
Gastritis Pancreatitis Cholecystitis Hepatitis Peptic ulcer (Perforated) IBS IBD Gastroenteritis Mesenteric ischemia Gastric cancer
By which mechanisms do NSAIDs damage the gastric lining?
- Cytotoxic effect on epithelial cells (direct damage)
- Inhibition of COX-1 enzyme
- decreased mucus production (decreased barrier - most important part!)
- decreased epithelial blood flow (decreased repair)
- suppress prostaglandin production (no effect of prostaglandins to decrease acid production) - Inhibition of COX-2 enzyme
- decreased angiogenesis
- suppress prostaglandin production (no effect of prostaglandins to prevent neutrophil adherence; mucosal damage results)
What does haematemesis look like?
May be bright red (think varices)
May be dark brown, like coffee grounds (think digested blood - bleeding peptic ulcer)
What symptoms might we seen in complications of peptic ulcers?
Fatigue (- iron deficiency anaemia)
Palpitations (- iron deficiency anaemia)
Dyspnoea (- iron deficiency anaemia)
Coffee ground vomit (- haematemesis of digested blood)
Melaena (- black, tarry stools)
Tachycardic (- Haemorrhagic shock)
Collapse/LOC (- Haemorrhagic shock)
Pale (- Haemorrhagic shock)
Agitation (- Haemorrhagic shock)
What are the symptoms of gastric outlet obstruction?
A clinical syndrome characterised by:
Epigastric pain
Postprandial vomiting (-due to mechanical obstruction)
Early satiety
Fullness
Bloating
Weight loss
What are the differentials for gastroparesis? (epigastric pain, postprandial vomiting)
Gastroduodenal ulcers (healing or active)
Gastric cancer
Pancreatitis
Small bowel obstruction
Narcotic bowel syndrome
Functional dyspepsia
Gastric outlet obstruction
IBS
IBD - chrons or ulcerative colitis
What are the causes of gastric outlet obstruction?
Peptic ulcer disease (- antrum scarring causing obstruction)
Pancreatic carcinoma (- extending into the duodenum/gastric outlet)
Gastric carcinoma (- uncommon, present like peptic ulcer disease, picked up mostly on biopsy)
What are the symptoms of gastric cancer?
Persistent indigestion
Trapped wind
Dyspepsia: upper abdominal pain fullness early satiety bloating nausea
Melaena
Loss of appetite
Fatigue
Weight loss
Anaemia: Fatigue, Dyspnoea, Pale
Jaundice
What is gastro-oesophageal reflux disease?
Symptoms or complications that result from the reflux of gastric contents up in to the oesophagus/oral cavity/lung.
Basically: retrograde movement of food
What are the complications of GORD?
Oesophagus:
Ulcer
Haemorrhage
Perforation
Oesophageal stricture
Barrett’s oesophagus
Adenocarcinoma of the oesophagus
What are the signs of gastric cancer?
Epigastric mass
Hepatomegaly
Ascites
Jaundice
Troisiers sign
Acanthrosis nigricans
Which medications are linked with peptic ulcers and GI bleeds?
- 6 main categories -
Antiplatelets
Corticosteroids
NSAIDs
Anticoagulants
Nicorandil (-potassium channel activator: causes refractory bleeds, only stop when nicorandil is stopped)
SSRIs
What are the common differentials for fresh blood in the stool?
Fresh bleeding usually suggests the rectum or anal canal as the source of blood (if the bleed is further up the tract the blood becomes MIXED in with the stool);
Haemorrhoids
Acute anal fissure (-trauma/constipation)
Colorectal tumours (-benign or malignant)
Acute proctitis
IBD (-ulcerative colitis can start as proctitis)
What is an acute anal fissure?
A break/tear in the anal canal (i.e. NOT the rectum). A common condition because the cause is often constipation - a very common condition.
Location: normally extend from the anal opening backwards IN (posteriorly in) to the anal canal, usually midline. The anal wall in the posterior midline is weaker and prone to tears.
Severity - the tear can extend down in to the underlying sphincter muscles
What are the symptoms of an anal fissure?
Severe pain in the anus - often when passing hard stools (ask about constipation);
Bright red anal bleeding - ask if any seen in toilet or on toilet paper
Anal fissure bleeding is never enough to cause anaemia.
What is a GI diverticulum?
An outpouching of the gut wall, generally at areas where perforating arteries (the arteries supplying the colon) enter; weak points.
Location: Colonic - most often the sigmoid colon, but can be in other parts of the GI tract
MOA: High pressure inside the lumen forces the mucosa to herniate through the muscular layer.
Note: 30% of people have diverticula by age 60, but most are ASYMPTOMATIC, they only have “diverticular disease” if the diverticuli are symptomatic
What is diverticulosis?
The presence of diverticula.
