Diarrhoea

Definition
Diarrhoea is defined as the passage of loose, liquid stool. Urgency is the sensation of the need to defaecate without being able to delay. It may indicate rectal irritability but also occurs where the volume of liquid stool is too large, causing the rectum to be overwhelmed as a storage vessel. Frequency merely reflects the number of stools passed and may or may not be associated with urgency or diarrhoea.
KEY POINTS
• Bloody diarrhoea is always pathological and usually indicates colitis of one form or another.
• Infective causes are common in acute transient diarrhoea.
• In diarrhoea of uncertain origin, remember the endocrine causes.
• Consider parasitic infections in a history of foreign travel.
• Alternating morning diarrhoea and normal/pellety stools later in the day is rarely pathological.
• Diarrhoea developing in hospitalized patients may be due to Clostridium difficile infectionbcheck for CD toxin in the stool.
Important diagnostic features
Acute diarrhoea
Infections
• Shigella/Salmonella: associated colicky abdominal pain, vomiting.
• Dysentery: blood and mucus in motions, ulcers in rectum and Entamoeba histolytica in the stool, fever, sweating, tachycardia.
• Cholera: severe diarrhoea, ‘rice water’ stool, dehydration, history of foreign travel.
• Giardiasis.
Antibiotics
Short-lived, self-limiting, mild colicky pain.
Pseudomembranous colitis
Caused by Clostridium difficile infection, characterized by severe diarrhoea which may be bloody but occasionally acute constipation may indicate severe disease. Characteristic features on colonoscopy.
Chronic diarrhoea
Small bowel disease
• Crohn’s disease: diarrhoea, pain prominent, blood and mucus less common, young adults, long history, chronic malnourishment and weight loss.
• Coeliac disease: history of wheat and cereals intolerance, may present in adulthood with chronic diarrhoea and weight loss, abdominal pains.
• ‘Blind loop’ syndrome: frothy, foul-smelling liquid stool, due to bacterial overgrowth and fermentation, usually associated with previous surgery, may complicate Crohn’s disease.
Large bowel disease
• Ulcerative colitis: intermittent, blood and mucus, colicky pains, young adults. May be a short history in first presentations. Rarely presents with acute fulminant colitis with acute abdominal signs.
• Colon cancer: older, occasional blood streaks and mucus, change in frequency may be the only feature, positive faecal occult blood, rectal mass.
• Irritable bowel syndrome: diarrhoea and constipation mixed, bloating, colicky pain, small stool pellets, never blood.
• Spurious: impacted faeces in rectum, liquefied stool passes around faecal obstruction, elderly, mental illness, constipating drugs.
• Polyps (villous) (rare): watery, mucoid diarrhoea, K+ loss, commonest in rectum.
• Diverticular disease (rare).
Systemic disease
Thyrotoxicosis, anxiety, peptides from tumours (VIP, serotonin, substance P, calcitonin), laxative abuse.
KEY INVESTIGATIONS
• FBC: leucocytosis (infective causes, colitis), anaemia (colon cancer, ulcerative colitis, diverticular disease).
• Anti α-gliadin Abs: coeliac disease.
• Thyroid function tests: hyperthyroidism.
• Stool culture: infections (remember microscopy for parasites).
• Proctoscopy/sigmoidoscopy: cancer, colitis, polyps (simple, easy, cheap and safe; performed in outpatients).
• Flexible sigmoidoscopy: cancer, polyps, colitis, infections (relatively safe, well tolerated, high sensitivity).
• Colonoscopy: colitis (extent and severity), pseudomembranous colitis.
• Small bowel enema: Crohn’s disease, coeliac disease, Whipple’s disease.
• Faecal fat estimation/ERCP: pancreatic insufficiency.

16 Rectal bleeding

KEY POINTS
• Anorectal bleeding is characteristically bright red, associated with defaecation, not mixed with the stool and visible on toilet paperboften associated with other symptoms of anorectal disease.
• Distal (left-sided/sigmoid) bleeding is characteristically dark red, with clots, may be mixed with the stool.
• Proximal colonic or ileal bleeding is characteristically dark red, fully mixed with the stool or occultbunless heavy when it may appear as  ‘distal’ or ‘anorectal’ in type.
• In children, Meckel’s diverticulum, intussusception and ileal tumours are common causes.
• In young adults, colitis, Meckel’s diverticulum and haemorrhoids are common causes.
• In the elderly, neoplasia, diverticular disease and angiodysplasia are common causes.
Important diagnostic features
Small intestine
• Meckel’s diverticulum: young adults, painless bleeding, darker red/melaena common.
• Intussusception: young children, colicky abdominal pain, retching, bright red/mucus stool.
• Enteritis (infective/radiation/Crohn’s).
• Ischaemic: severe abdominal pain, physical examination shows mesenteric ischaemia or AF, few signs, later collapse and shock.
• Tumours (leiomyoma/lymphoma): rare, intermittent history, often modest volumes lost.
Proximal colon
• Angiodysplasia: common in the elderly, painless, no warning, often large volume, fresh and clots mixed.
• Carcinoma of the caecum: more often causes anaemia than PR bleeding.
Colon
• Polyps/carcinoma: may be large volume or small, ?associated change in bowel habit, blood often mixed with stool.
• Diverticular disease: spontaneous onset, painless, large volume, mostly fresh blood, previous history of constipation.
• Ulcerative colitis: blood mixed with mucus, associated with systemic upset, long history, intermittent course, diarrhoea prominent.
• Ischaemic colitis: elderly, severe abdominal pain, AF, bloody diarrhoea, collapse and shock later.
Rectum
• Carcinoma of the rectum: change in bowel habit common, rarely large volumes.
• Proctitis: bloody mucus, purulent diarrhoea in infected, perianal irritation common.
• Solitary rectal ulcer: bleeding post-defaecation, small volumes, feeling of ‘lump in anus’, mucus discharge.
Anus
• Haemorrhoids: bright red bleeding post-defaecation, stops spontaneously, perianal irritation.
• Fissure in ano: extreme pain post-defaecation, small volumes bright red blood on stool and toilet paper.
• Carcinoma of the anus: elderly, mass in anus, small volumes bloody discharge, anal pain, unhealing ulcers.
• Perianal Crohn’s disease.
KEY INVESTIGATIONS
• FBC: anaemiabtumours/chronic colitis.
• Clotting: bleeding diatheses.
• PR/sigmoidoscopy: anorectal tumours, prolapse, haemorrhoids, distal colitis.
• Abdominal X-ray: intussusception.
• Colonoscopy: diverticular disease, colon tumours, angiodysplasia.
• Angiography: angiodysplasia, small bowel causes (especially Meckel’s). (Needs active bleeding 0.5 ml/min, highly accurate when positive, invasive, allows embolization therapy.)
• Labelled RBC scan: angiodysplasia, small bowel causes, obscure colonic causes. (Needs active bleeding l ml/min, less accurate placement of source, non-invasive, non-therapeutic.)
• Small bowel enema: small bowel tumours.

15 Jaundice

Definitions
Jaundice (also called icterus) is defined as yellowing of the skin and sclera from accumulation of the pigment bilirubin in the blood and tissues. The bilirubin level has to exceed 35–40 mmol/l before jaundice is clinically apparent.
KEY POINTS
• Jaundice can be classified simply as pre-hepatic (haemolytic), hepatic (hepatocellular) and post-hepatic (obstructive).
• Most of the surgically treatable causes of jaundice are post-hepatic (obstructive).
• Painless progressive jaundice is highly likely to be due to malignancy.
Differential diagnosis
The following list explains the mechanisms behind the causes of jaundice.
Pre-hepatic/haemolytic jaundice
Haemolytic/congenital hyperbilirubinaemias
Excess production of unconjugated bilirubin exhausts the capacity of the liver to conjugate the extra load, e.g. haemolytic anaemias (e.g. hereditary spherocytosis, sickle cell disease, hypersplenism, thalassaemia).
Hepatic/hepatocellular jaundice
Hepatic unconjugated hyperbilirubinaemia
• Failure of transport of unconjugated bilirubin into the cell, e.g.Gilbert’s syndrome.
• Failure of glucuronyl transferase activity, e.g. Crigler–Najjar syndrome.
Hepatic conjugated hyperbilirubinaemia
Hepatocellular injury. Hepatocyte injury results in failure of excretion of bilirubin, e.g. infections: viral hepatitis; poisons: CCl4, aflatoxin; drugs: paracetamol, halothane.
Post-hepatic/obstructive jaundice
Post-hepatic conjugated hyperbilirubinaemia
Anything that blocks the release of conjugated bilirubin from the hepatocyte or prevents its delivery to the duodenum.
Courvoisier’s law
‘A palpable gallbladder in the presence of jaundice is unlikely to be due to gallstones.’ It usually indicates the presence of a neoplastic stricture (tumour of pancreas, ampulla, duodenum, CBD), chronic pancreatitic stricture or portal lymphadenopathy.
KEY INVESTIGATIONS
• FBC: haemolysis.
• LFTs: alkaline phosphatase (cholestasis), g-GT and transaminases (hepatocellular).
• Clotting: PT (elevated in cholestatic and hepatocellular jaundice).
• Urinary urobilinogen
→
Haemolytic
• Blood film
• Reticulocyte count
• Autoantibody screen
Obstructive
U/S CBD and gallbladder
CBD dilated
Gallstones
ERCP
Surgery
→
Hepatocellular
• Viral titres: including hepatitis
A/B/C, CMV, EBV
• Ultrasound: details of hepatic
parenchyma.
• Liver biopsy: hepatocellular
disease
→
→
CBD dilated
No gallstones
?Ca pancreas/CBD
ERCP +/– stent
CT scan/MRCP
→→
Other cause found
ERCP
CT scan
Surgery

14 Abdominal swellings (localized): lower abdominal

 

KEY POINTS
• Retroperitoneal mass: no movement with respiration, difficult to
delineate, resonant to percussion.
• Bowel masses: often mobile, may be well defined.
• Pelvic mass: difficult to ‘get below’, bimanually palpable on PR/PV
examination.
Sigmoid colon
• Diverticular mass: tender, ill defined, rubbery hard, non-mobile.
• Paracolic abscess: acutely tender, ill defined, ?fluctuant, systemic
upset.
• Carcinoma: hard, craggy, non-tender unless perforated, immobile,
associated with altered bowel habit/obstructive symptoms.
• Faeces: firm, indentable/‘malleable’, mobile with colon.
• Normal: only in a thin person, non-tender, chord like.
Caecum/ascending colon
• Appendix mass/abscess: acutely tender, ill defined, ?fluctuant,
systemic upset.
• Carcinoma: hard, craggy, non-tender unless perforated, immobile,
associated with anaemia/weight loss and anergia.
Terminal ileum
• Crohn’s mass: tender, ill defined, rubbery hard, non-mobile.
• Tuberculous mass: mildly tender, ill defined, firm, associated
with cutaneous sinuses, ?systemic TB.
Ovary/fallopian tube
• Cyst: may be massive, usually mobile, ?bimanually palpable
on PV examination.
• Neoplasm.
• Ectopic pregnancy: very tender, associated with PV bleeding/
intra-abdominal bleeding and collapse.
• Salpingo-oophoritis: very tender, bimanually palpable, associated
with PV discharge.
Bladder
• Generally: midline swelling, extends up towards umbilicus,
dull to percussion, non-mobile, cannot ‘get below’ it.
• Retention of urine: stony dull to percussion, associated with
desire to pass urine, disappears on voiding/catheterization.
• Transitional cell carcinoma: hard, irregular, fixed, may be
associated with dysuria, haematuria and desire to pass urine on
examination.
Uterus
• Pregnancy: smooth, regular, fetal heart sounds heard/
movements!
• Fibromyoma: usually smooth, may be pedunculated and
mobile, non-tender, associated menorrhagia.
• Uterine carcinoma: firm uterus, may be tender, irregular only
if tumour is extrauterine, associated PV bloody discharge.
Rectum
Carcinoma: firm, irregular, non-tender, relatively immobile,
associated alteration in bowel habit/PR bleeding.
Urachus (rare)
Cyst: small swelling in midline, ?associated umbilical discharge.
Other
Pelvic kidney: smooth, regular, non-tender, non-mobile.
KEY INVESTIGATIONS
• FBC: anaemiabtumours.
• WCC: lymphomas, Crohn’s disease, appendicitis/diverticulitis.
• LFTs: liver lesions.
• Ultrasound: ovarian lesions, appendix/diverticular mass or abscess,
Crohn’s mass, pelvic kidney, ovarian lesions, pregnancy, uterine lesions,
bladder tumours.
• CT scan: retroperitoneal/mesenteric cysts, omental deposits,
appendix/diverticular mass or abscess, Crohn’s mass. Allows guided
drainage of abscesses and biopsy of some tumours.
• Colonoscopy: colonic tumours, diverticular disease.
• Small bowel enema: small intestinal tumours, ileal Crohn’s disease.
• Barium enema: diverticular disease, colonic tumours.
• MSU: infected urinary retention.
• β-HCG: pregnancy.XD369VGTNWWZ