Gastro Flashcards
hepatic causes of jaundice (high indirect bilirubin)
Gilbert’s (decr UDPG activity)
Crigler Najjar (no UDPG)
Hepatitis
Newborn jaundice (not enough UDPG or lignin to deal with incr haem catabolism from conversion of HbF to HbA)
hepatic causes of jaundice (high direct bilirubin)
Hepatitis Drugs that impair excretion Rubin Johnson syndrome (no cMOAT for excretion) Tumours Cirrhosis
Post-Hepatic causes of jaundice
Due to high conjugated bilirubin:
Gallstones
Biliary strictures/obstruction
Cholangitis
Pancreatic or biliary tree cancer
All lead to cholestasis
What happens to bilirubin when it is unconjugated in the blood and liver?
Blood - bound to albumin
Liver - bound to ligandin
What sort of bilirubin is toxic and what does it cause in the brain?
Indirect is insoluble so cannot be excreted and builds up
Kernicterus due to brain toxicity
Which enzyme conjugates bilirubin and what happens if it is not present or has decr activity?
UDPG
Decr activity: Gilbert’s
Not present: Crippler Najjar
what happens to bilirubin in the gut?
Converted to urobilinogen via gut bacteria
then 90% is converted to stercobilin and excreted in faeces
10% absorbed into portal circulation and goes back to liver. 9% of this is recycled back to gut and 1% goes to kidneys and is excreted in urine
What colour is the pee and poo with:
obstructive jaundice?
pre-hepatic jaundice?
Obstructive: Dark wee, pale poo
Pre-hepatic: dark wee and poo (overwhelm liver conjugating enzymes)
What is a potential consequence of pre-hepatic jaundice?
Excess haem from haemolysis results in excess synthesis of bile salts which can result in precipitation of GALLSTONES
-> cholestasis -> obstructive jaundice
4 categories of mechanisms of diarrhoea
Osmotic
(excess unabsorbed substrates in gut lumen retain fluids)
Secretory
(stimulation of excretory mechanisms from enterocytes)
Inflammatory
(altered membrane permeability leads to exudation of protein, blood, mucus)
Altered intestinal motility
(slow or fast)
Common underlying cause of osmotic diarrhoea
FODMAPS (IBS)
Common underlying causes of secretory diarrhoea
Bacterial toxins
- ETEC
- Cholera
Laxative abuse
Hyperthyroidism
Common underlying causes of inflammatory diarrhoea
IBD
Invasive bacteria
- Shigella
- Salmonella
- Clostridium difficile
- Campylobacter
Entamoeba histolytica
CMV colitis
Common underlying causes of altered motility diarrhoea
SLOW: Anatomical defects causing intestinal stasis -strictures -blind loops (diverticulitis) -surgery
FAST:
- IBS
- Thyrotoxicosis
- Diabetic neuropathy
Appearance of poo with - inflammatory - secretory - osmotic Diarrhoea
Inflamm - blood and mucus, small volume
Secretory: watery, >1Lvol
Osmotic: fatty,
Acute abdomen - which causes need laparotomy and which don’t
Need laparotomy:
- Generalised peritonitis (perf ulcer, diverticulum, appendix, bowel, gallbladder)
- Ruptured organ (liver, spleen, AAA, ectopic pregnancy)
Doesn’t need:
- local peritonitis (cholecystitis, diverticulitis, salpingitis)
- suspected abscess
- localised ileus
- colicky pain (patient restless)
Maybe:
-SBO
Management of Acute abdomen
Treat shock w 2 large bore cannulas w crystalloid (Hartmann's) fluids ECG Vitals Group and hold Blood cultures Antibiotics (cef and met) Analgesia (IV morphine PRN) IV fluids Plain AXR and erect CXR Nil by mouth Antiemetics
Management of abdominal trauma (blunt)
§ ABCs, fluid resus and stabilisation
§ Surgery ?
□ Hollow organ injuries -> laparotomy
□ Solid organ injuries -> laparotomy if hemodynamically unstable or high transfusion requirements
Management of abdo trauma (penetrating)
§ ABCs § Fluid resuscitation and stabilization § Gunshot wounds require laparotomy § Laparotomy if penetrating trauma and □ Shock □ Peritonitis □ Evisceration □ Free air in abdomen □ Blood in NG tube, catheter or on DRE
§ Local wound exploration in some instances
Treatment for peritonitis
IV rehydration and electrolyte balance correction
IV antibiotics (cephalosporin, tazosin or carbepenem)
Laparotomy - exploratory peritoneal lavage and correction of anatomical defects
Treatment of ascites
1st line
○ Salt restriction (>2g daily)
○ Diuretics: spironolactone, frusemide
○ Weight loss
If refractory (treatment with diuretics is inadequate)
○ Therapeutic/palliative ascitic taps
○ IV albumin
? Liver transplantComplications of ascites and the treatment
Spontaneous bacteiral peritonitis if they develop fever, chills, abdo pain, hypotension, ARF etc
Treatment: IV antibiotics (cephalosporin) and IV albumin
Investigations for a suspected hernia
Ultrasound +/- CT
List different types of hernias
Inguinal hernias (direct vs indirect)
Femoral hernia
Umbilical
Paraumbilical (below or above umbilicus)
Epigastric (through lines alba above umbilicus)
Incisional hernia
Obturator hernia
- What does reducible mean?
2. What does irreducible mean?
hernia
- contents can be pushed back into their rightful position
- hernia cannot be pushed back into their right place = stuck = incarcerated.
May or may not be strangulated
What does incarcerated mean? (hernia)
Herniated tissue is trapped in a hernial sack and cannot be pushed back into position (=irreducible)
Doesn’t imply anything about blood supply.
obstructed vs strangulated in conte
Obstructed - bowel caught in hernia obstructing the passage of bowel contents through
Strangulated - Blood supply is compromised and bowel becomes ischaemic
3 questions to ask about a lump found on examination
- Can you get above it? (no-> hernia)
- Yes -> Is it separate to the testes? (No-> testicular tumour)
- Does it transilluminate? (Yes -> fluid as in cyst or hydrocoel; no-> solid)
Direct vs indirect hernia
Direct: directly through defect in abdominal wall. older patients.
- Medial to inferior epigastric artery)
Indirect: through deep inguinal ring into inguinal canal. Associated w congenital defect in males (patent processes vaginalis). younger patients.
- Lateral to inferior epigastric artery)
What is the site that direct hernias usually occur in called and why are the anatomical landmarks?
Hasselbach’s triangle
- lateral edge of rectus sheath
- inferior epigastric vessel
- inguinal ligament
Where do femoral hernias occur?
Femoral canal: medial to femoral vein, below inguinal ligament
Which type of hernia is more common in women and what is a common complication?
Femoral hernia . More likely to be irreducible and to strangulate.
Complications of hernias
Incarceration
Strangulation
Richter’s hernia
Obstruction
Richter’s hernia - what is it? how might a patient present?
Once side of small bowel wall becomes incarcerated in a hernia which may strangulate that section of bowel wall. presents w sepsis and tachycardia + lump
When might you perform surgery for a hernia?
Emergency if hernia is strangulated.
Elective if:
- obstruction (change in bowels)
- Pain
- Nuisance, aesthetic
Contents of the spermatic cord
Vas deferens testicular artery & vein genital branch of genitofemoral nerve lymphatics cremaster muscle \+/- hernial sac
What is the management of hernia?
Do nothing if small and asymptomatic.
Surgery to prevent strangulation or evisceration, for pain or aesthetic. Laparoscopic or open mesh repair.
What genetic alleles is coeliac associated wiht?
HLA-DQ2 and HLADQ8 are found in close to 100% patients but also in 20% of the general population
What sort of hypersensitivity is coeliac disease?
Type 4 hypersensitivity against gliadin, found in gluten
Histopathology of coeliac disease: 3 features
- Villous atrophy and crypt hyperplasia
- Increased #s plasma cells and lymphocytes in LP
- Increased IELs (CD4 T cells)
What part of bowel does coeliac mainly affect? What affect does this have on absorption?
Duodenum and jejunum
Affects absorption of Vitamin B, C and folate (proximal), mostly
Protein, fat and fat soluble vitamins (A, E, D, K) distally. absorbed so only affected in severe disease.
What sort of anaemia is associated w Coeliac disease?
Iron deficiency (microcytic)
or pernicious anaemia (B12, macrocytic)
Symptoms of coeliac disease
D • Diarrhoea, steatorrhea
• Weight loss, fatigue
• Bloating, gas
• Anaemia - iron deficiency »_space; B12, folate deficiency
• Symptoms of vitamin, mineral deficiency (apthous ulcers, angular stomatitis)
• Osteoporosis in older people
• Failure to thrive in infants
• Symptoms improve with gluten free diet and relapse when gluten reintroduced
Diagnosis of coeliac
Small bowel biopsy before starting GF diet
Bloods: FBE, Iron studies, UEC, B12, folate
Serology (anti gliadin and anti tTG antibodies + IgA)
HLA-DQ typing
What does coeliac put you at risk for?
Other autoimmune conditionts (autoimmune thyroiditis, T1D)
Cancers - EATL small bowel lymphoma, adenocarcinoma of small bowel and oesophageal carcinoma
What are the main symptoms for Crohn’s vs UC
Crohns: abdominal cramps, diarrhoea, weight loss (malnutrition), fever
UC: rectal bleeding, urgency, tenesmus, abdominal cramps
Physical distribution of Crohns vs UC
Crohn’s
- anywhere from mouth to anus
- Skip lesions
- Commonly terminal ileum
UC
- rectum -> colon (not proximal to ileocaecal jan)
- continuous
- always starts in rectum
Potential complications of UC vs Crohns
Crohns:
- Strictures
- Fissures -> risk of perforation
- Abscess
- Fistulae
- Perianal disease
US
- toxic megacolon -> risk of perforation
- incr risk colon cancer
Extra colonic manifestations of Crohn’s vs UC
Crohns
- perianal fistulae and skin tags
- renal stones
- cholelithiasis
- oral ulcers
Both
- rashes, erythema nodosum
- arthritis, analysing spondylitis
- uveitis, episcleritis
- PSC
- fatty liver
Cobblestoning and mucosal islands are a feature of what IBD condition?
Crohn’s
Effect of surgery in crohn’s vs UC
Crohn’s - recurrence is common
UC - surgery can cure.
Treatment of IBD
Crohns: stop smoking + only fluids during exacerbation
- Steroids (C-oral pred; UC-IV methylpred)
- 5ASA therapy +/- antibiotics
- Immunosuppressants (azathioprine, methotrexate, infliximab)
- Surgery for:
- Crohn’s: presence of complications
- UC: failed medical therapy, toxic megacolon, bleeding, pre-cancerous change
Investigating IBD
Bloods (FBE, CRP, UEC, LFT, blood cultures)
Stool MCS (shigella, campylobacter, e coli, C. diff, salmonella -> all inflamm pattern diarrhoea)
Abdo x-ray Erect CXR (perf?)
Colonoscopy and biopsy
management of IBS
Low FODMAPS diet
Incr fibre intake
Antismasmotic (hyoscine) before meals
Reassurance, relaxation or stress reduction therapy
Red flags that rule out IBS as a DDX
Weight loss Fever Nocturnal defecation anaemia blood or pus in stool abnormal gross finding on endoscopy
What is the criteria for IBS?
Abdo pain relieved w defecation
Abdo pain assoc w change in fréquency OR consistency of stool
+/- bloating, passing mucus, straining, urgency, incr or decr stool frequency
Managing an acute abdomen
- ABCDE
- Airway, breathing, circulation
- Disability: BSL, GCS
- E: expose patient (Evidence for trauma/aneurysm/GI bleed?) - insert 2 large bore (18 or 16gu) cannulas
- Bloods: blood cultures, group and hold, FBE, UEC, LFT, CRP, ABG, Trop, beta HCG
- ECG
- Check obs: pulse, BP, JVP, saO2
- ECG if > 50
- Ceftriaxone and metronidazole
- IV morphine PRN, metaclopramide
- IV fluids: hartmann’s
- FAST scan +/- Portable plain erect CXR and AXR
- Call surgical reg
- Prep for theatre
Preparation for theatre
- Nil by mouth
- DVT prophylaxis: LMWH, 3. TEDs
- Catheterise (IDC)
- NGT (decompression and prevents aspiration)
- PPIs
+/- analgesia, antiemetic, anxiolytic
Management of abdominal trauma
- ABCDE primary surgery (+/- O2 or intubation)
- secondary surgery + NGT, IDC
- Bloods (incl group and hold), urinalysis
- FAST scan (free fluid), Abdominopelvic X-ray (bone breaks, pneumoperitoneal, air fluid levels, hernias) , CT (not if haemodynamically unstable)
- Fluid resuscitation (2 large bore cannulas w hartmann’s )
- Surgery - laparotomy
Management of appendicitis
IV fluids + electrolyte correctance
Prompt appendectomy
Metronidazole +ceftriaxone pre-op
Complications of appendicitis
Perforation
Abscess
Examination tests for appendicitis
Tenderness at McBurney’s point (1/3 from ASIS to umbilicus)
Rovsing’s sign: when LIF is pressed, pain felt more strongly in RIF than left
Psoas sign = retrocaecal appendix (pain on flexion of hip against resistance OR passive hyperextension of hip)
Obturator sign =pelvic appendix (flexion then external or internal rotation about R hip causes pain)
Where does diverticular disease usually affect? where is the pain generally felt?
Sigmoid colon
LLQ
