Diarrhoea, Constipation, Appendicitis and Diverticulitis Flashcards
Compare the 2 broad causes of Diarrhoea in;
- Stool volume
- Response to fasting
- Stool osmolality
- Ion gap
Osmotic;
- Moderately increased
- Diarrhoea stops
- Normal to increased
- > 100mOsm/kg
Secretory;
- Very large
- Continues
- Normal
- <100mOsm/kg
Briefly outline the Secretory cause of Diarrhoea
- Electrolyte transport abnormal
- Secretion of Cl/ HCO3 into Lumen of gut
- Na follows and so does H2O
Suggest 3 non-osmotic, non-secretory causes of Diarrhoea
Insufficient Na absorption from gut lumen;
- Reduced SA for absorption
- Mucosal disease/ bowel resection (Coeliac, IBD)
- Reduced contact time (Intestinal rush)
What are 4 risk factors for Constipation
- Female (3:1)
- Certain medications
- Low levels of physical activity
- Increasing age (also common <4)
What are 3 types of causes of Constipation
- Normal Transit Constipation
- Slow Colonic Transport
- Defecation problems
What causes Normal Transit Constipation?
List 2 causes of Defecation problems
- Psychological stress
- Cannot coordinate muscles of defecation
- Disorders of Pelvic Floor/ Anorectum
List 5 cause of Slow Colonic Transport
- Large colon (Megacolon)
- Fewer an shorter peristaltic movements
- Nervous system diseases (MS, Parkinson’s)
- Systemic disorders (diabetes, hypothyroidism)
- Fewer Interstitial cells of Cajal (intestinal pacemaker cells)
List 5 treatments of Constipation
- Psychological support (If Normal Transit Constipation)
- Increased fluid intake
- Increased activity
- Increases fibre intake (Only useful if mild)
- Laxatives (Osmotic, Stimulatory, Stool softeners)
Describe the Appendix (including itself, its muscle, blood supply)
- A diverticulum of the caecum
- Has a complete longitudinal layer of muscle (colon has incomplete bands called Teniae Coli)
- Blood Supply: Branch of Ileocolic branch of SMA, that comes up through a mesentery (mesoappendix)
Why is the location of the appendix important?
This changes the presentation of acute appendicitis
What are the 3 broad categories of Appendicitis?
- Acute (Mucosal oedema)
- Gangrenous (Transmural inflammation and necrosis)
- Perforated (Can-> Peritonitis)
Describe the classic explanation for Appendicitis
- Blockage of Appendiceal Lumen creates a raised pressure in the appendix
Causes venous pressure to rise (causing oedema in walls)->;
- Harder for arterial blood to supply appendix
- Ischaemia, then bacterial invasion follows
What is the alternative explanation for Appendicitis?
Viral or bacterial infection causes mucosal changes that allows bacterial invasion of Appendix walls
How does Appendicitis present classically? (<60% of cases)
- Poorly localised peri-umbilical pain
- Anorexia
- Nausea and vomiting
- Fever
- After 12 to 24 hrs, pain is felt more intensely in Right Iliac Fossa
Describe the pain changes in Appendicitis, considering that the appendix is intra-peritoneal
Initially;
- Appendix swells, stretching Visceral Peritoneum’s afferents
- Pain referred to T9/ T10 Dermatome
After 12-24hrs;
- Enlarges to touch wall of abdomen and irritate Parietal Peritoneum
- Pain localised to Right Iliac Fossa
Why may you not get Right Iliac Fossa pain if the Appendix is Retro-Caecal or Pelvic in position?
Where else may you get pain?
- RIF parietal peritoneum does not come into contact with inflamed appendix
- Supra pubic
- Right sided rectal
- Vaginal
Suggest 2 patient groups in which it may be harder to diagnose Appendicitis
Children;
- Difficult to get full accurate history
- Symptoms are more non-specific
Pregnancy;
- Altered anatomy
What are 5 signs of Appendicitis?
- Appear SLIGHTLY ill
- Slight fever/ tachycardia
- Lie quite still (to avoid irritation to peritoneum)
- Localised Right Quadrant tenderness
- Rebound tenderness in right iliac fossa (Pain felt on rebound_
Where is McBurney’s Point?
What is significant about it?
- 1/3 of way from ASIS to Umbilicus
- Generally this is where the Appendix lies
What are 2 treatments of Appendicitis?
- Open appendicectomy
- Laparoscopic appendicectomy
What is Diverticulosis?
Is it symptomatic?
Where do most occur?
The presence of Diverticula- Outpouchings of Mucosa and Submucosa herniation through Muscularis layers
- Asymptomatic
- Sigmoid colon, along where nutrient vessels penetrate bowel wall
State the suspected cause of Diverticula forming
Increased intra-luminal pressure (low fibre diet)
Compare Diverticulosis, Acute Diverticulitis and Diverticular Disease
Diverticulosis;
- Presence of Diverticula
Acute Diverticulitis;
- Inflammation/ perforation of Diverticula (+/- bleeding and abscess formation)
Diverticular Disease;
- Pain due to Diverticula, WITHOUT inflammation/ infection
What percentage of people with Diverticulosis develop Acute Diverticulitis?
Up to 25%
Describe the pathophysiology of Acute Diverticulitis
Similar to Classic Appendicitis
- Entrance to Diverticular blocked (E.g by faeces)
- Inflammation eventually allows bacterial invasion of Diverticula wall
- Can lead to perforation
Compare Uncomplicated and Complicated Diverticulitis
Uncomplicated;
- Inflammation + small abscesses confined to colonic wall
Complicated;
- Larger abscesses, Fistula, Perforation
List 5 symptoms of Acute Diverticulitis
- Ab pain (usually left lower quadrant as sigmoid colon is here)
- Fever
- Bloating
- Constipation (Inflammation can block colonic lumen)
- Haematochezia (Large amounts of blood loss)
List 4 signs of Acute Diverticulitis
- Localised abdominal tenderness
- Distension
- Reduced bowel sounds
- Signs of peritonitis (due to perforation)
What are 5 investigations for Acute Diverticulitis
- Blood tests (Raised WBCs, pregnancy test)
- Ultrasound
- CT
- Colonoscopy if large haematochezia
- Elective colonoscopy (after symptoms settled) to determine cause of symptoms if unclear
How do you treat Acute Diverticulitis non-surgically?
- Antibiotics
- Analgesia
- Fluid resuscitations
(In uncomplicated diverticulitis, may only need analgesia and antibiotics)
When do you treat Acute Diverticulitis surgically?
If perforation or large abscesses need to be drained
Partial colectomy may be needed
