Case 11 Flashcards
Arterial supply of caecum
Superior mesenteric artery
Branches into ileocolic artery
Branches into right and left caecal arteries
Pain course in Appendicitis
Initially, vague pain in periumbilical region due to stretching of visceral peritoneum.
Then severe pain in right lower quadrant due to irritation of parietal peritoneum
Phrenicolic ligament
Attaches transverse colon to diaphragm
Omental appendices
Small pouches of peritoneum on the surface of the colon, filled with fat
Teniae Coli
3 strips of muscle on surface of the bowel wall.
Contract to shorten the bowel
(Mesocolic, free, omental)
Haustra
Sacculations in bowel wall caused by contraction of teniae coli
Components of solids found in rectum
Cellulose/Epithelial cells
Bacteria
Salts
Stercobilin
Gaseous components found in rectum
Indol and Skatol
Production of gases found in rectum
Indol and Skatol produced by breakdown of amines by bacteria
Pouch of Douglas is also known as
Rectouterine pouch
Anorectal ring
Fusion of internal and external anal sphincters, and puborectalis muscle
Epithelium lining anal canal and rectum
Columnar
Epithelium lining anal canal below pectinate line
Non keratinised stratified squamous
Vascular supply above pectinate line in anal canal
Superior rectal artery and vein
Vascular supply below pectinate line in anal canal
Inferior rectal artery and vein
Nerve supply above pectinate line in anal canal
Sensitive to…
Hypogastric plexus
Sensitive to stretch
Nerve supply below pectinate line in anal canal
Sensitive to…
Inferior anal nerves
Sensitive to pain, temperature, touch and pressure
Non pathological haemorrhoids
Vascular cushions found within anal canal.
Help to maintain faecal continence
Type of muscle in Internal Anal Sphincter
Smooth (involuntary, controlled by autonomic NS)
Type of muscle in External Anal Sphincter
Skeletal
Nerve supply to External Anal Sphincter
Pudendal Nerve
Process of Defaecation
Contraction of external anal sphincter and puborectalis muscle
Increases anorectal angle and compresses anal canal
Main site of sodium reabsorption in the GI tract
Jejunum
Main site of potassium reabsorption in the GI tract
Jejunum (and ileum)
How is potassium reabsorbed into the jejunum?
Solvent drag i.e. by the flow of water, not through specific ion channels
Site of potassium secretion into GI tract
Colon
Regulator of potassium secretion into GI tract
Aldosterone
Main site of calcium reabsorption in the GI tract
Duodenum
How is calcium reabsorbed into the GI tract?
TRPV channels (Transient Receptor Potential Vallinoid)
Hormone regulator of calcium uptake in the GI tract
Calcitrol
Intracellular buffer required for calcium uptake in the GI tract
Calbindin
Transferrin
Glyco-protein found in blood which binds to iron and tranports it
High ferritin suggests
Iron storage problem - haemochromatosis, or chronic disease process
Low ferritin suggests
Iron deficiency causing anaemia
Low transferrin causes
anaemia
Ferritin
Intracellular protein which stores iron
Role of Enteric (NANC) neurons in regulation of secretion/absorption in the GI tract
Release VIP - Chloride ion secretion
Role of Enterochromaffin cells in regulation of secretion/absorption in the GI tract
Release serotonin - Chloride ion secretion
Role of D cells in regulation of absorption/secretion in the GI tract
Release somatostatin - chloride and sodium ion absorption
Actions of Somatostatin
Inhibits G cells (inhibits secretion of gastrin)
Stimulates sodium and chloride ion absorption
Role of enteric neurons in regulation of absorption/secretion
Release encephalins - chloride and sodium ion absorption
NANC neurons
Non adrenergic, non cholinergic neurons
Role of luminal bacteria on regulation of secretion/absorption in the GI tract
Release enterotoxins (e.g. cholera toxin) - chloride ion reabsorption
Role of mast cells in regulation of secretion/absorption in the GI tract
Release histamine - chloride ion absorption
Effect of aldosterone on secretion/absorption in the GI tract
Sodium ion and water reabsorption in the GI tract
Verner Morrison Syndrome
Increased VIP
Increased Cl- secretion into GI tract
Draws water into lumen
Watery diarrhoea
Why do SSRIs (e.g. Prozac) cause diarrhoea?
Increased availability of serotonin
Increased Cl- secretion into GI tract
Draws water into lumen
Excitatory neurotransmitters in enteric nervous system
ACh and Substance P
Inhibitory neurotransmitters in enteric nervous system
VIP and Nitric Oxide
Intestinal wall contractions after a meal (Postprandial)
Shortening/Lengthening of individual villi
Segmentation mixing via circular smooth muscle
Pendular mixing via longitudinal smooth muscle
Peristaltic waves (transports contents approx 5cm)
Migrating Motility Complexes
Once/hour during fasting, contents is moved over a long distance (0.5m) due to MOTILIN released by M cells
Flushing of the intestines
Peristaltic Reflex
Stretch receptors in submucosal plexus activated due to bolus in lumen.
Relaxation of intestinal wall ahead of bolus.
Contraction of intestinal behind bolus
SIP syncytium
Smooth Muscle cells
Interstitial cells of cajal
PDGFR-alpa+
Interstitial cells of Cajal
Show pacemaker activity due to cyclic release of Ca2+ from stores
Motilin released from… in response to…
Released from M cells in the duodenum in response to fat and acid
Neurotensin released from… in response to…
N cells in ileum in response to fat
Effect of Neurotensin on intestinal epithelial cells
Decreases motility
Effect of motilin
Stimulates gastric emptying
Enteroglucan released from… in response to …
L cells in the distal ileum in response to glucose and fat
Effect of enteroglucan
Decreases motility
Effect of VIP on intestinal smooth muscle cells
Relaxation
Effect of encephalins on intestinal motility
Stimulates Peristaltic reflex
Hirschsprung’s disease
Aganglionic congenital megacolon
Part of GI tract have no ganglion cells so cannot function - MEGACOLON
Muscle remains contracted.
Distention of area of colon proximal to affedted area
Why is Cl- exchanged for HCO3- in colon?
Bicarbonate neutralises acidity produced by bacterial symbiotic flora
Factors affecting mass movement in the colon
Parasympathetic intrinsic reflex pathways (vagal neurons)
Gastrin
CCK
Immune function of Greater Omentum
Forms adhesions near an inflamed organ (e.g. appendix), enclosing it off to protect other organs
Epiploic foramen
Connects greater and lesser sacs of peritoneum
Clinical presentation of Pneumoperitoneum
Abnormal presence of gas in peritoneum.
Affected diaphragm (C3,4,5)
Therefore, referred pain in tip of shoulder
Vertebral level of coeliac trunk
T12
Left gastric artery supplies
Oesophagus and lesser curvature
Splenic artery supplies
Spleen and part of pancreas
Common hepatic artery supplies
Proximal duodenum
Liver
Gallbladder
Vertebral level of Superior Mesenteric Artery
L1
Inferior Pancreaticoduodenal artery supplies
Duodenum and Pancreas
Right colic artery supplies
Ascending colon
Middle colic artery supplies
Proximal 2/3 of transverse colon
Vertebral level of Inferior Mesenteric Artery
L3
Left colic artery supplies
Distal 1/3 of transverse colon
Descending colon
Ligament of Treitz
Attaches duodenojejunal flexure posterior to abdominal wall
Surface anatomy: Where are the small intestines located?
Epigastric and umbilical region
Surface anatomy: Where is the ileocaecal junction located?
Right Iliac Fossa
Jejunum has a …. diameter than ileum
Greater
Ileum has a …. wall than jejunum
Thinner
Plicae circularis
Circular folds/large valvular flaps
Project into the lumen of the small intestine
(more in jejunum than ileum)
Continue across entire circumference of bowel
Jejunum has (long/short) vasa recta and (few/many) arcades
Long
Few
Ileum has (long/short) vasa recta and (few/many) arcades
Short
Many
Symptoms of intussusception
Pain
Distension
Constipation
Absent bowel sounds
Meckel’s Diverticulum
Congenital
Slight bulge in small intestine
Remnant of yolk sac
Normal diameter of caecum
9cm
McBurney’s Place
Appendicular orifice used in surgical excision of appendix
1/3 of the distance from Right ASIS to the umbilicus
Normal diameter of colon
6cm
What are diverticula?
Mucosa extruding through weakened muscular wall of colon
Cause of diverticulitis
Faeces obstructing neck of diverticula causing accumulation of bacteria
Diverticulitis normally affects
Sigmoid colon
Symptoms of diverticulitis
Pain/Tenderness/Guarding in Left Iliac Fossa Palpable mass Fever Constipation Tachycardia
Complications of diverticulitis
Bowel perforation
Abscess formation
Fistulae into adjacent organs
Generalised peritonitis
Lymphatic drainage of rectum/anal canal above pectinate line
Internal iliac nodes
Lymphatic drainage of anal canal below pectinate line
Superficial inguinal canal
Why are internal haemorrhoids painless?
Supplied by Hypogastric plexus which only responds to stretch
Why are external haemorrhoids acutely painful?
Supplied by inferior anal nerves
Respond to pain, temperature, touch and pressure
Indirect inguinal hernia
Lateral to inferior epigastric vessels
Direct inguinal hernia
Medial to inferior epigastric vessels
Young boy with inguinal hernia descending into the scrotum
Indirect
Elderly man with inguinal hernia, palpable in abdominal wall above pubic tubercle
Direct
Nerves involved in sympathetic innervation of GI tract
Splancnhnic Nerves
Spinal level of foregut
T5-T9
Spinal level of midgut
T10-T12
Spinal level of hindgut
L1/2
Splanchnic nerve supplying foregut
Greater
Splanchnic nerve supplying midgut
Lesser
Splanchnic nerve supplying hindgut
Lumbar
Area of referred pain from foregut
Epigastric region (below nipples, above umbilicus)
Area of referred pain from midgut
Umbilical region
Area of referred pain from hindgut
Left and right flanks
Lateral and anterior thighs
Adenomas are
neopastic polyps
Polyps are
Precursors for carcinoma
Adenomas in the intestine arise from
Glandular epithelium
Ulcerative colitis
Diffuse mucosal inflammation, limited to the colon
Symptoms of Ulcerative colitis
RECTAL BLEEDING
Diarrhoea
Urgency
Abdominal pain
UC almost always affects
Rectum (Proctitis)
Crohn’s Disease
Patchy, transmural inflammation affecting any part of the GI tract (Mouth to anus)
Crohn’s Disease commonly affects…
Large bowel and terminal ileum
Toxic megacolon is an acute complication of…
Ulcerative colitis
How does Ulcerative colitis cause toxic megacolon?
Ulcerating inflammatory processes dissect into the wall of the colon
What is seen on a radiograph of toxic megacolon?
Early - accumulation of gas over a segment of the colon. Scalloped edge due to oedema and spasm.
Late - dilatation (maximal in transverse colon), abnormal haustra and thumb-printing
Thumb-printing
Caused by inflammation e.g. UC, Crohn’s Disease, Pseudomembranous colitis, ischaemic colitis
Contraindicated procedures in Toxic Megacolon
Barium enema
Colonoscopy
Early sign on radiograph of bowel perforation
Subserosal dissection of luminal gas into bowel wall
i.e. gas from the bowel invades the bowel wall
Inflammation in Crohn’s disease usually occurs where?
Ileocaecal region (75-80%)
Symptoms of inflammation in Crohn’s disease
Right lower quadrant pain Tenderness Low grade fever Anorexia and weight loss Diarrhoea
How does an obstruction occur in Crohn’s disease? (4)
Fibromuscular proliferation and deposition of collagen in bowel wall (narrowing of lumen)
Inflammatory infiltration
Fibrosis (above)
Spasm
Oedema
Symptoms of obstruction in Crohn’s disease
Post-prandial cramps Distention Borborgymi (noisy bowel sounds) Vomiting (due to high grade obstruction) Weight loss
Symptoms of enteroenteric fistulisation
Usually asymptomatic
Symptoms of Enterovesical fistulisation
UTIs
Pneumoturia (air in urine)
Symptoms of retroperitoneal fistulisation
Psoas abscess signs
e.g. pain in back, hip or knee and a limp
Symptoms of enterocutaneous fistulisation
Drainage via a scar on the skin
Symptoms of perianal fistulisation
Pain, drainage
Symptoms of rectovaginal fistulisation
Drainage of faeces/air through vagina
Treatment of perianal fistulae
Seton - stitch to hold open fistula, allowing its contents to drain out rather than becoming infected.
‘String-sign’
String-like appearance of a contrast filled bowel due to severe narrowing of lumen
Why would ‘string-sign’ be seen in inflammation in Crohn’s Disease?
Narrowing of lumen due to transmural thickening and irritative spasm
Red flags for IBD
Anaemia Weight loss Fever Perianal disease Occult blood/Faecal WBCs
Effect on IBD risk of smoking
Decreases risk of UC
Increases risk of CD
Effect on IBD of appendicectomy
Protects against UC
No effect on CD
MOA of mesalazine
5-ASA is the active moiety
Diminishes inflammation of bowel by blocking COX
Reduces prostaglandin production
5 Aminosalicylic Acid drugs
Mesalazine
Balsalazine
Olsalazine
What is the problem with sulfalazine treatment?
When cleaved it forms 5ASA and sulphapyridine
Sulphapyridine is clinically toxic when circulating
Indication for mesalazine
Mild to moderate Ulcerative colitis (active and in maintaining remission)
Crohn’s Disease
Indication for prednisolone
Severe active UC or CD
MOA of prednisolone
Glucocorticoid analogue
Binds to steroid receptor acting as a transcription regulator.
Increased anti inflammatory proteins
Decreased inflammatory immune factors
Route of administration of prednisolone
Oral
Route of administration of hydrocortisone
IV
ADRs of prednisolone
Cushing’s
Weight gain
Immunosuppression
Contraindications of prednisolone
Cushing’s
Immunosuppressed
Active infection
MOA of Budesonide
Glucocorticoid analogue
Binds to steroid receptor acting as a transcription regulator.
Increased anti inflammatory proteins
Decreased inflammatory immune factors
Why is budesonide used in ulcerative colitis?
Corticosteroid - reduces inflammation
Controlled ileal release (a common site of inflammation in UC)
Immunosuppressant used in UC
Cyclosporin
Immunosuppressant used in CD
Methotrexate
MOA of Azathioprine
Immunosuppressant
Active metabolite interferes with nucleic acid synthesis in WBCs (especially T cells)
Reduces production of inflammatory mediators by WBCs
Antibiotics used for Crohn’s disease
Metronidazole
Ciprofloxacin
MOA of Metronidazole
Antibiotic
Inhibits nucleic acid synthesis in
MOA of ciprofloxacin
Antibiotic
Inhibitor of topoisomerase II/DNA gyrase
MOA of Infliximab
Anti-TNF drug
Competitive inhibitor of TNF alpha receptor
Benefits of Kock pouch over Brooke Ileostomy
Faecal continence maintained
No external appliance
Ileal-pouch Anal Anastomoses
Formation of a new rectum surgically
Will always have watery stools
Faecal continence maintained
Drug therapy for mild/moderate active disease in UC
Mesalazine
Drug therapy for severe active disease in UC
Corticosteroids
Anti-TNF therapy
Drug therapy in maintaining remission in UC
Mesalazine
Azothioprine (Immunosuppressant)
Drug therapy in moderate active disease in CD
Budesonide (Corticosteroid)
Dietary therapy
Antibiotics
Drug therapy in severe active disease in CD
Corticosteroids
Anti TNF drugs
Drug therapy in maintaining remission in CD
Azathioprine (Immunosuppressant)
Anti TNF drugs
Brunner’s Glands
Submucosal glands which secrete alkaline mucus-like fluid into duodenal lumen
Peyer’s Patches
Aggregates of lymphocytes in wall of jejunum/ileum
Coeliac Disease
Inflammation of upper small bowel mucosa which improves when gluten is withdrawn from the diet
Clinical features of Coeliac Disease
Steatorrhoea/Diarrhoea Abdominal Pain Ulcers/Algular stomatitis Flatulence Weight loss
Why do coeliac patients get steatorrhoea?
Duodenal cells cannot signal for CCK release
No contraction of gallbladder
Reduces fat digestion and absorption
Why do coeliac patients get flatulence?
Fermentation of undigested food by gut flora
Why are coeliac patients at risk of osteomalacia?
Low calcium absorption
Findings in colonoscopy of coeliac patient
Erythematous, inflamed, scalloped lining of upper GI tract
Site of absorption of B12
Terminal ileum
Pseudopolyp
Piece of mucosa, where the surrounding mucosa has eroded from around it.
Bacteria commonly associated with gastroenteritis in the UK
Campylobacter Jejuni
Salmonella
Indication of C.Diff infection on colonoscopy
Yellow plaques
Treatment of C. Diff
Metronidazole
Erythema Nodosum
Red lumps on skin of shins (and sometimes thighs and forearms)
Associated with IBD
Apthous Stomatitis
Non contagious, benign mouth ulcers
Associated with IBD
Episcleritis
Inflammation of episclera - between sclera and conjunctiva
Associated with IBD
Anterior Uveitis
Inflammation of iris and ciliary body
Associated with IBD
Pyoderma Gangrenosum
Painful ulcers, usually on legs
Associated with IBD
Central arthropathy in IBD associated with which genotype
HLA B27
Central arthropathy seen in IBD
Ankylosing spondylitis
Sacroiliitis
Features of liver disease associated with IBD
Primary sclerosing cholangitis
Steatosis - fatty liver
Chronic hepatitis
Cirrhosis
Extraintestinal manifestations in IBD which are unrelated to disease activity:
Central arthropathy
Liver disease
Transmission of Clostridium Difficile
.Person to Person
Faeco oral
Who is at high risk of contracting clostridium difficile?
Elderly
Hospitalised
On antibiotics (destory gut flora)
Clinical manifestation of Clostridium difficile infection
Colitis - diarrhoea, abdo pain, anorexia
Increased WCC
Reduced renal function
Fever
Management of Clostridium difficile
Nutrition and fluid balance
Metronidazole
Infection control
FMT - faecal microbiological transplantation
Transmissionof Campylobacter
Ingestion of contaminated food (usually chicken)
Management of campylobacter
Self-limiting, does not normally require Abx
Erythromycin may shorten duration of symptoms
Clinical manifestation of campylobacter infection
Small bowel - Diarrhoea, N+V, Fever, Cramping
Transmission of salmonella
Ingestion of poorly cooked/contaminated food (chicken + eggs)
Clinical manifestation of salmonella
Diarrhoea N+V Headache Cramps Fever
Incubation period for campylobacter
1-7 days
Symptoms of campylobacter last
2-7 days
Incubation period for salmonella
8-48 hours
Symptoms of salmonella last
48-96 hours
Why is salmonella infection a public health issue?
Takes 9 weeks for an infected individual to become culture negative.
potential to infect others during that time
Non GI manifestations of salmonella
Osteolmyelitis (bone infection)
Focal infections e.g. of prosthetic joints
Meningitis
Management of salmonella infection
Normally no antibiotics
In severe cases:
Quinolones
Macrolides
Cephalosporins
MOA of fluoroquinolones
Topoisomerase II inhibitor
MOA of macrolides
Protein synthesis inhibitor - prevents translocation
MOA of cephalosporins
Inhibit cell wall synthesis (Beta lactams)
Transmission of E. Coli
Ingestion of contaminated food
Management of E. Coli
Supportive
Isolation
Ciprofloxacin if severe
MOA of ciprofloxacin
Fluoroquinolone
DNA gyrase inhibitor
Transmission of cholera
Faecally contaminated food/water
Clinical manifestation of cholera
Watery diarrhoea
Management of cholera
aggressive rehydration (Rehydration solution, Oral rehydration salts)
Transmission of Shigella
Faeco-oral
Management of Shigella
Rehydration
Ciprofloxacin if severe
Clinical manifestation of Shigella Dysenteriae
Diarrhoea - small amount containing blood and mucus
Abdominal cramps
Fever
Incubation period for shigella
12 hours to 6 days
Symptoms of shigella last
3-7 days
Clinical manifestation of norovirus
Small bowel affected
Fever
Vomiting
Diarrhoea
Incubation period for norovirus
24-48 hours
Antibiotic treatment for C.Diff
Metronidazole or vancomycin
Causative Abx should be continued if possible
Antibiotic treatment for Campylobacter
Azithromycin
Antibiotic treatment for Salmonella
Ciprofloxacin
Antibiotic treatment for E.Coli (VTEC)
Avoid - Increases risk of Haemolytic Uraemic Syndrome by release of toxin from bacteria
HUS can lead to renal damage or death
Antibiotic treatment for Giardia (Lamblia)
Metronidazole
Transmission of Giardia(Lamblia)
Contaminated water
Symptoms of Giardia (Lamblia)
Diarrhoea - bulk, offensive smelling, pale
Abdo bloating
Anorexia
Nausea
Transmission of Cytospordium
Contaminated water
Cytospordium particularly affectes…
Immunocompromised - associated with AIDS and low CD4
Clinical manifestation of Cytospordium
Small intestine
Diarrhoea, abdo cramps, weight loss
Clinical manifestation of Cytospordium in px with AIDS
Small intestine
Diarrhoea, abdo cramps, weight loss
PLUS Cholangitis and cholecystitis
Management of cytospordium
None with immunocompetent
Immunocompromised patients - HAART
Management of Entamoeba Histolytica
Metronidazole
Luminal amoebacide
Treatment of cyclospora
Usually self limiting
Can be given cotrimoxazole
CCDA agar plate used for
Campylobacter
SMAC agar plate used for
E.Coli
XLD agar plate used for
Salmonella
Shigella
TCBS agar plate used for
Vibrio Cholera
Lynch syndrome increases risk of
Cancers (inc. colorectal)
Gene mutations causing adenomatous colorectal polyps
APC
MYH-AP
Gene mutations in Lynch syndrome
MSH-2, MLH-1
Inheritance pattern of FAP
Autosomal dominant
Gene mutation in FAP
APC
Inheritance pattern of MYH-Associated Polyposis
Autosomal recessive
Regions of bowel most commonly affected by colorectal cancer
21% sigmoid colon
38% rectum
‘Signet ring’ cells
Where mucin produced by adenocarcinoma displaces cell nucleus to side of cell.
Poor prognosis
Symptoms of colorectal cancer
Change in bowel habit Tenesmus Rectal bleeding palpable mass Symptoms of anaemia (due to GI bleeding)
Location of APC gene
5q21
Role of APC gene
Tumour suppressor
K-ras
Protein which regulates cell division.
Mutated in 30-50% of colorectal cancers
Allows adenoma to become adenocarcinoma
SMAD2 and SMAD4
Intracellular proteins which mediate TGF-beta - Therefore regulating transcription, apoptosis and differentiation.
May be lost in colorectal cancer
Role of p53 in formation of cancer from adenoma
Coordinates response to DNA damage, oxidative stres and aberrant proliferative signals
Dukes’ classification of colorectal cancer - A
Tumor confined to mucosa
Dukes’ classification of colorectal cancer - B1
Tumor growth into muscularis propria
Dukes’ classification of colorectal cancer - B2
Tumor growth into muscularis propria and serosa (full thickeness)
Dukes’ classification of colorectal cancer - C1
Tumor spread to 1-4 lymph nodes
Dukes’ classification of colorectal cancer - C2
Tumor spread to >4 lymph nodes
Dukes’ classification of colorectal cancer - D
Distant metastases (liver, lung, bone)
Premalignant lesions for colorectal cancer in Lynch Syndrome patients
MMR (mismatch repair) deficient crypts
PD-1 inhibitors/blockade
Activate immune system to attack tumors.
Used in tumours with mismatch repair deficiency
Management of Lynch Syndrome
Aspirin (600mg/day)
Vaccines - Micoryx and Monocyte derived dendritic cells
PD-1 blockade
5-FU Response
S phase arrest
p53 accumulation
Upregulation of p53 target genes
Apoptosis
Small bowel is positioned…
centrally
Diameter of small bowel
3cm
Ileus
Bowel stops peristalsis
Causes abnormal bowel dilatation despite no mechanical blockage
Intususception
One part of bowel invaginates into another part of bowel
Volvulus
Loop of intestine twists around itself and the mesentary
Closed loop obstruction in large bowel.
Pneumatosis Intestinalis
Intramural gas in bowel wall due to gaseous cysts
will eventually perforate
What does pneumatosis intestinalis look like on AXR?
Gas tracks in intestinal wall (black line outlining lumen)
Rigler’s Sign
Triangle-shaped pockets of gas in peritoneal cavity
Suggestive of bowel perforation
Why is an erect CXR useful in detecting perforation?
Gas rises up above liver - black line over liver, under diaphragm
Falciform sign
Occurs in bowel perforation when gas rises up either side of the falciform ligament
Can be seen on a supine abdominal X Ray
Football sign on a AXR suggests
Bowel perforation - gas rises up in a circular fashion
Barium follow through in Crohn’s patient shows:
Rose thorn ulcers (spikes on outer surface)
Stricturing
Thumb printing
When is oral contrast indicated in imaging of the bowel?
Suspected Acute inflammation
When is Portal Venous IV contrast indicated in imaging of the bowel?
Suspected: Obstruction Perforation Ischaemic bowel Acute inflammation Acute GI bleed
After IV contrast is administered, non enhancing bowel suggests…
Ischaemia - since contrast was not able to reach that area
What is the significance of carrying out CT scan of the patient prone and supine?
Normal bowel contents will move when the patient changes from supine to prone.
A polyp or other lesion will not.
Indication for Colonoscopy
Colonic symptoms
Suspected cancer/colitis
Ideally <40yrs
Indication for minimum prep CT
Colonc symptoms
>80yrs
Indication for CT Pneumocolon (Virtual colonoscopy)
40-80yrs (outside age for colonoscopy)
Suspected extracolonic cancer
Failed colonoscopy
T1 MRI
Fat = white
Water = black
Good for anatomy
T2 MRI
Fat = black
Water = white
Good for pathology
When is a chest X Ray indicated in abdominal pathology?
Perforation suspected - pneumoperitoneum
Vertebral level of kidneys
T12-L3
Benefits of ingestion of plant sterols and stanols
Reduce total blood cholesterol
Marasmus
Undernourishment causing weight to be significantly lower than expected (variable loss of muscle and fat)
Metabolism is normal
Seen in anorexia nervosa
Cause of Kwashiokor
Deficiency in dietary protein
Mechanism for kwashiorkor
Reduces intracellular glutathione/GSH
Peroxidation of cell membranes
Membranes become leaky
Fluid moves from blood into interstitium due to high osmotic pressure
Sources of vitamin A
Dairy
Fish
Meat (liver)
Function of vitamin A
Colour vision
Antioxidant
Deficiency of vitamin A
Keratosis (permanent goosebumps)
Xeropthalmia (dry, inflamed conjunctive)
Poor night vision
Sources of vitamin D
Eggs
Liver
Fish oil
Role of sunlight in vitamin D pathway
Converts 7-dehydrocholesterol into vitamin D
Function of vitamin D
Increases absorption of calcium in the GI tract
Deficiency of vitamin D
Rickets/Osteomalacia
Parathyroid hormone is released when…
Plasma calcium falls
Function of PTH
To increase plasma calcium by:
Increased absorption from GI tract
Increased reabsorption in kidney tubules
Increased release from bone
Source of vitamin E
Spinach
Almonds
Sunflower seeds
Function of vitamin E
Antioxidant - protects against atherosclerosis
reduces risk of stroke and MI
Vitamin E deficiency
Haemolytic anaemias
Sources of vitamin K
Green leafy vegetables
Liver
Function of vitamin K
Clotting factor synthesis (Prothrombin, VII, IX, X)
Vitamin K deficiency
Bruising/Bleeding
Sources of vitamin B1 (thiamine)
Lean meat Fish Eggs Legumes Green vegetables
Vitamin B1 is also known as ..
Thiamine
Function of vitamin B1/Thiamine
Involved in carbohydrate metabolism - a coenzyme in the link reaction
Deficiency of vitamin B1/Thiamine
Beri beri
Wet Beri beri
Affects cardiovascular system: Tachycardia Dyspnoea Oedema Raised JVP
Due to thiamine deficiency
Dry Beri beri
Affects peripheral nervous system: Loss of reflexes Loss of muscle function Tingling or loss of sensation Confusion
Sources of vitamin B2/Riboflavin
Milk Liver Kidneys Heart Meat Green vegetables
Function of vitamin B2/Riboflavin
Component of FAD - involved in hydrogen transfer in oxidative phosphorylation
Deficiency of vitamin B2/riboflavin
Dermatitis
Angular Chelitis
Glossitis
Hypersensitivity to light
Sources of vitamin B3/niacin
Most foods (rare deficiency)
Function of vitamin B3/niacin
Component of NAD - involved in hydrogen transfer in oxidative phosphorylation
Deficiency of vitamin B3/niacin
Pellagra - diarrhoea, dermatitis, dementia, death
Deficiency of vitamin B5/Pantothenic acid
Neuropathy
Abdominal pain
Deficiency of B6
Irritability Convulsions Anaemia Vomiting Skin lesions
Who is at risk of B7 (Biotin) deficiency?
Alcoholics Px on antacids Px with partial gastrectomy Pregnant women lactating womn
Sources of vitamin B9 (Folic acid)
Liver
Green vegetables
(Also synthesised by intestinal bacteria)
Function of vitamin B9/Folate
Haematopoiesis
Nucleic acid synthesis
Development of neural tube
Deficiency of B9/Folate
Anaemia
GI disturbance and diarrhoea
Folic Acid (Vitamin B9) supplementation is recommended for….
Women trying to conceive
Women during their first 12 weeks of pregnancy
Vitamin B12 (Cobalamin) deficiency
Pernicious anaemia
Loss of muscle power
Spinal nerve demyelination
Function of Vitamin B12/Cobalamin
Red blood cell production
Amino acid metabolism
CNS function
Function of vitamin C
Collagen synthesis
Redox reactions
Antioxidant
Deficiency of vitamin C
Scurvy - increased risk of infection, poor wound healing, anaemia
Vitamin C is also known as…
Ascorbic acid
Function of iron
Haemoglobin synthesis
Electron transport
Iron deficency
Spooning of nails
Whitening of sclera
Anaemia
Zinc deficiency
Delayed puberty and small stature
Dermatitis
Alopecia
Poor wound healing
Magnesium deficiency
Muscle weakness
Neuromuscular dysfuncion
Function of phosphorus
Bone mineralisation
Phosphorus deficiency
Rickets and osteomalacia
Iodine deficiency
Enlarged thyroid gland
Copper deficiency
Impaired mental development
Failure to keratinise hair
Skeletal and vascular problems
MOA of Mebeverine
Muscarinic ACh receptor antagonist
Prevents Calcium entry into cells
Therefore, antispasmodic
ADRs of Mebeverine
Constipation
Indigestion
Dry mouth
Dry skin
Contraindications of mebeverine
Paralytic ileus
MOA of loperamide
Mu-opioid receptor agonist
Reduces myenteric plexus activity
Reduces peristalsis
ADRs of Loperamide
Dizziness
Headache
Flatulence
Nausea
Contraindications of loperamide
Ulcerative colitis
Bacterial Colitis
MOA of Cinchocaine
Blocks voltage gated sodium channels in nociceptive fibres
Prevents action potential propagation along axon to CNS
i.e. local anaesthetic
ADRs of cinchocaine
Bradyarrhythmias
CNS effects
Hypotension
Route of administration of antihaemorrhoidals
Topical application as a gel
Rectal suppository
Local anaesthetic for haemorrhoids is combined with…
Anti inflammatory (NSAID or steroid) Peripheral vasoconstrictor (e.g. phenylephrine)
Site of absorption of ethanol
Stomach
Site of absorption of calcium ions
Duodenum
Jejunum
Proximal ileum
Site of absorption of iron ions
Duodenum
Jejunum
Proximal ileum
Site of absorption of glucose (and other sugars)
Duodenum
Jejunum
Proximal ileum
Site of absorption of fatty acids
Duodenum
Jejunum
Proximal ileum
Site of absorption of vitamins
Duodenum
Jejunum
Proximal ileum
Site of absorption of Vitamin C
Proximal ileum
Site of absorption of Vitamin B12
Distal ileum
Site of absorption of Bile salts
Distal ileum
Cholesterol
Small bowel
Site of absorption of monovalent ions and water
Small and large bowel
