Gastrointestinal Flashcards
Colorectal cancer
Risk factors, pathophysiology, types, manifestations, diagnosis, treatme
Risks: low physical activity, high BMI, alcohol, smoking, high fat and red meat, low fibre
Pathophysiology: genetic and environmental factors contribute to benign adenoma polyps, which slowly develop into neoplastic and malignant polyps or carcinomas that invade lining
Types:
* Right tumours (caecum & ascending colon) are large, bulky, palpable and cause anaemia,
* Left are small button masses that ulcerate, cause bleeding, hard stool and obstruction
Manifestations: pain, mass, anaemia, bloody stool, obstruction, distention
Dx: faceal occult, colonoscopy, CT
Tx: resection, chemo, radiation
Ulcerative colitis
Description & brief pathophysiology, manifestations
Chronic inflammatory disease causing ulceration of the colonic mucosa, absess formation and necrosis, usually rectum and sigmoid colon, that is immune mediated
Manifestations: diarrhoea, bloody stool, cramping, dehydration, weightloss, through regular relapse and remission
Crohn’s disease
Inflammatory condition similar to UC but affects the entire intestinal wall of both large and small intestine (rarely rectum), also immune mediated and genetic predisposition, that causes ulcerations, skip lesion fissures, fitsulae, strictures and obstructions
Manifestaions: no specific symptoms, but signs of irritable bowel such as diarrhoea, occasional bleeding, abdominal pain and weight loss, nutritional deficiencies
Peptic ulcer
Description, causes, types (list)
Ulceration in the mucosal lining of the stomach or duodenum caused by excessive acid secretion or disruption in mucosal barrier caused by infection, NSAIDs, alcohol
Gastric, duodenal, stress
Gastric ulcers
Description, main causes, symptoms
- Ulcers of the stomach that occur in the antrum, near parietal cells, and are chronic
- Acid production is normal but mucosa is breached due to drugs, infection, gastritis, or duodenal reflux
- Intermittent pain in epigastric region that is alleviated with food
Duodenal ulcers
Description, main causes, symptoms
- Most common, caused by increased pariatel cells, elevated gastrin, gastric emptying and infection
- Relapse/remission rather than chronic, and they heal spontaneously
- Symptoms of epigastric pain, esp when stomach is empty, blood in vomit or stool
Stress ulcer
Description, main causes, symptoms
- Acute peptic ulcer due to severe illness, trauma, neural injury or emotional stress, that occurs at multiple sites
- Bleeding is the main symptom
Malnutrition
Lack of nourishment from inadequate amounts of calories, protein, vitamins and minerals, due to improper diet or alterered digestion/absorption
Starvation
Extreme malnutrition and hunger from lack of nutrients
* Short term: 3-4 days, stimulates release of stored glucose and production from non-carb molecules
* Long term: breakdown of ketones and FAs, eventual proteolysis and death if not restored
Failure to thrive
- Inadequate physical development of an infant or child, causing deceleration of weight gain, low weight-height ratio, and head circumference
Intestinal obstruction
Description, types, causes
Any condition that prevents normal flow of chyme through the lumen, can be** simple** (most common - mechanical blockage) or **functional **(motility failure)
Causes:
* Hernia (protrusion of intestine through weak abdominal muscles)
* Intussusception (part of intestine slips/telescopes into itself)
* Volvulus (twisting)
* Diverticulosis (small bulges due to lining weakness)
* Paralytic ileus
Vomiting/emesis
- Forceful emptying of the stomach by GI contraction aand reverse peristalsis of the oesophagus
- preceded by N and retching
- Projectile vomiting caused by direct stimulation of vomiting centre in brain
Diarrhoea
Description, causes, manifestations
- Increase in frequency of defecation, and fluidity and volume of faeces (>3x/day)
Causes:Excessive fluid drawn in by osmosis, excessive secretion of fluids by mucosa, or excessive motility
Rotarivus can cause severe diarrhoea in children
Gastrointestinal bleeding
Types, signs
Upper GI: oesophagus, stomach or duodenum (ulcers, retching)
* Haematemesis, black stools (melaena), +occult
Lower GI: jejunum, ileum, colon, rectum (polyps, IBD, cancer, haemorrhoids)
* Haematochezia (frank bleeding from rectum)
Abdominal distension
Swelling of the abdomen, occuring in bowel hypermobility, fluid accumulation in peritoneal cavity (ascites - portal hypertension, low albumin), bowel obstruction
Diverticula & diverticulosis
Diverticula:Herniations of the mucosa and submucosa though defects in the circular muscle layers, forming pouches
Diverticulosis: assymptomatic diverticula
Diverticulitis
Infection/inflammation of diverticula
Aetiology of diverticulitis
Colonic wall structure:
* weak points in the muscle layer, usually where arteries penetrate tunica muscularis
* Increased pressure = thickened wall + narrow lumen (reduced faecal bulk due to lack of fiber)
Genetics: influence on incidence, and location of diverticula
Lifestyle: low fiber diet, high BMI, active lifestyle, vitamin D deficiency
* DM: weakens immune system
NSAIDs: increase risk of perforation and diverticular bleeding
Issues with colonic motility and segmentation
Pathophysiology of diverticulitis
- First, weakness in intestinal wall & increased luminal pressure causes formation of diverticula
- Neck of diverticula becomes obstructed by faecolith (hard stool), causing bacterial overgrowth and inflammation
- Oedema & infammatory infiltrate lead to perforation into adjacent bowel or cause peritonitis
- If vascular supply is compromised = haemorrhage
Manifestations of diverticulitis
- Fever, N/V
- Altered bowel habits
- Hx of abdominal pain (dull, colic, diffuse) with flatulence, distension
- Present pain in LLQ (severe, deep) & lower extremety (perforation)
- Dysuria, pyuria, urinary frequency (irritation or urinary system)
- Lower GI bleeding (bright red, massive and stops suddenly)
- Hx UTI/pneumaturia (colovesicular fistula) or feculent vaginal discharge (uterine/vaginal fistula)
Diagnosis - imaging
- CT: choice for active diverticulitis, to identify diverticula, colonic thickening, abscess, fistulas, perforation (also excludes other pathologies such as ovarian abscess and aneurysms)
- **X-ray: ** signs of intestinal irritation and 2/3rds of visceral perforation
- Endoscopy: use in non-active (due to risk of perforation & peritonitis), used to diagnose and determine site of bleeding, either nasogastric, colonoscopy or sigmoidoscopy
- US & MRI
Diagnosis - lab investigations
- FBC: leukocytosis (but most have normal %)
- Hb: blood loss
- Type, cross match blood: in event of bleeding
- APTT (coagulation), INR (prothrombin time), platelet count [active bleeding]
- U&E (low K, high urea)
- Blood culture: prior to AB therapy
- Urinalysis/urine culture: ?UTI (+leukocytes & nitrites) or haematuria
Emergency care of diverticulitis
Non-acute diverticulosis: if no never, leukocytes, palpable mass or signs of active infection = discharged on antispasmodics, high fiber diet, analgesia and follow up sigmoidscopy
Mild diverticulitis: if no systemic symptoms or signs of peritonitis = discharged on low residue diet, oral ABs, to return if +pain or systemic infection
Acute divertulitis: hospitalised, broad spectrum IV ABs
Nursing management for diverticulitis
- Vitals & SaO2 2/24
- Abdominal assessment 4/24
- NPO & FBC, IDC
- O2 tx if required
- IV fluid resucitation
- NGT to drainage if vomiting or colonic obstruction, record output
- BC & PR bleeding
- Pain assessment
- RIB, TEDS, leg excercises, coughing exercises
- BB, MC, EC, OC
- Blood and IV AB if required
Diverticular bleeding management
- Most common cause of massive LGI bleeding
- Admission for obs, NPO and IV fluids, stop anticoagulant therapy
- Urgent colonoscopy with haemostasis or selective angiography with embolisation of bleeding vessel
- Use of intra-arterial vasopressin or epinephrine injection
- Surgery once bleeding is located if pt is haemodynamically unstable, requires >6units of blood and has recurrent bleed
Diverticulitis complications
Haemorrhage: herniation into muscular wall, breaching the circulation, made worse by NSAIDs
Fistulas: in chronic or recurring acute, where inflammation causes adhesions with other organs
* Colovesicular most common, and colovaginal in women (requires surgical resection)
Abscess: inflammatory infiltrate - may be palpable, or suggested if not responding to tx (diagnosed by CT/US and treated by drainage)
Colonic obstruction: repeated episodes cause muscular wall thickening (NB must be differentiated from other causes such as tumour, colitis etc.)
Perforation & peritonitis: severe clinical presentation, diagnoses by radiographs (never by endoscopy), treated by surgical resection
Surgical management of diverticulitis
- Percutaneous abscess drainage
- Surgery for: peritonitis & perforation, failed percutaneous drainage, bowel obstruction, fistula
- Hartmann’s procedure to remove portion of sigmoid
- Temporary colostomy may be needed during resection if unsafe to rejoin
Prevention of diverticulitis
- High fiber and fluid intake
- Avoid constipation, consider psyllium (bulk forming), methylcellulose (absorbs liquid to make bulky, soft stool)
- Avoid trigger foods such as corn, nuts, seeds
- Finish AB course
- Physical activity
