GI Flashcards
Mx of a mild to moderate flare of UC that does not respond to topical or oral aminosalicylates?
Add oral steroids (note, do NOT stop oral ASAs)
What condition has the strongest association with H. pylori infection?
Duodenal ulceration
What is used 1st line for Mx of hepatic encephalopathy
Lactulose
Which scoring system would be used to determine the severity of an upper GI bleed and whether or not they could be managed safely as an outpatient?
Glasgow Blatchford score
What is Budd Chiari syndrome?
Hepatic vein thrombosis.
Usually seen in the context of underlying haematological disease or another procoagulant condition e.g. polycythaemia vera, thrombophilia, pregnancy, COCP
What classic triad of features is seen in Budd Chiari syndrome?
1) Abdo pain: sudden onset, severe
2) Ascites –> abdo distension
3) Tender hepatomegaly
1st line investigation in Budd Chiari syndrome?
US with Doppler flow studies
If a patient with UC colitis had a severe relapse or >=2 exacerbations in the past year, what should they should be given to maintain remission?
either oral azathioprine or oral mercaptopurine
What is the 1st line laxative indicated in acute constipation that is not associated with opioid use? (after diet)
Bulk forming e.g. ispaghula husk
Which laxative is often given for opioid-induced constipation?
Docusate
2nd line laxative indicated in acute constipation that is not associated with opioid use? (after ispaghula husk)
Osmotic laxative e.g. macrogol
What is the diagnostic investigation of choice in pancreatic cancer?
High resolution CT
Mx of pharyngeal pouch?
Surgical repair and resection
Mx options in perianal fistula?
1) Oral metronidazole (if symptomatic)
2) Draining seton (for complex fistulae)
What is a seton used in perianal fistula?
A seton is a piece of surgical thread that is run through the fistula to allow continuous drainage while the fistula is healing.
This ensures that the fistula doesn’t heal containing pus within, which would result in further abscess formation.
What should patients with ascites 2ary to liver cirrhosis be given?
Aldosterone antagonist e.g. spironolactone
Stepwise Mx of achalasia?
1) pneumatic (balloon) dilation (less invasive and quicker recovery time than surgery)
2) Heller cardiomyotomy (if recurrent or persistent symptoms)
What does a Heller cardiomyotomy involve?
Involves cutting of the thick muscle around the lower oesophagus and upper stomach to allow for passage of food and drink.
Give 4 causes of acute liver failure
1) paracetamol OD
2) alcohol
3) hepatitis (usually A or B)
4) acute fatty liver of pregnancy
What are the 2 best ways to measure acute liver failure?
1) prothrombin time (best) i.e. INR
2) albumin level
How can PPIs affect sodium level?
Can cause hyponatraemia through SIADH
Where is biopsy taken from for diagnosis of coeliac?
Jejunal biopsy
Or duodenal biopsy
What are the 2 areas most affected in coeliac?
Jejunum & duodenum
What 2 factors are used to monitor treatment in haemochromatosis?
1) ferritin
2) transferrin saturation
What is Desferrioxamine?
An iron chelating agent
What autoantibodies can be seen in primary sclerosing cholangitis?
p-ANCA
What is Sister Mary Joseph nodule?
A sign of metastasis to periumbilical lymph nodes, classically from a gastric cancer primary.
Umbilical protrusion is a common finding with this nodule.
What are 3 key complications of C. diff?
1) Toxic megacolon
2) Pseudomembranous colitis
3) Bowel perforation & sepsis
What monoclonal Ab is sometimes used in the management of C. diff infection?
Bezlotoxumab –> targets C. diff toxin B
What is medical management of RECURRENT C. diff infection:
a) within 12 weeks of symptom resolution
b) after 12 weeks of symptom resolution
a) oral fidaxomicin
b) oral vancomycin OR oral fidaxomicin
What C. diff antigen is specifically tested for in stool samples?
Glutamate dehydrogenase
What is the gold standard for investigating E. coli diarrhoea?
Stool culture & sensitivity
What is HUS?
A rare but serious condition that can lead to renal failure, anaemia and thrombocytopenia.
What is HUS most commonly caused by?
Infection with certain strains of E. coli bacteria.
What age does HUS typically affect?
<5 y/o
What triad is seen in HUS?
1) AKI
2) Microangiopathic haemolytic anaemia
3) Thrombocytopenia
What are some possible symptoms of HUS?
1) bloody diarrhoea
2) abdominal pain
3) vomiting
4) decreased urine output.
How does E. coli 0157 cause HUS?
E. coli 0157 produces the Shiga toxin which destroys RBCs.
What can increase the risk of HUS in E. coli gastroenteritis?
Giving Abx
Which virus typically causes gastroenteritis with respiratory symptoms?
Adenovirus
What is the most common causative organism of bacterial gastroenteritis?
Campylobacter jejuni
What bacteria can cause food poisoning from reheated rice?
Bacillus cereus
Incubation period of Campylobacter?
2-5 days
1st line Abx in campylobacter infection?
Clarithromycin
Consider in patients with severe symptoms or other risk factors, such as HIV or HF.
What is it always important to ask about in a diarrhoea history?
1) Recent foreign travel
2) Recent history of hospitalisation or Abx therapy
Bloody diarrhoea in viral vs bacterial gastroenteritis?
Viral - often non-bloody
Bacterial - often bloody
Fever in viral vs bacterial gastroenteritis?
Viral - milder fever
Bacterial - often higher fever
Does suspicion of bacterial cause of gastroenteritis warrant stool microscopy and culture?
Yes
How can bacillus cerus be implicated in infective endocarditis?
Can cause infective endocarditis in IVDU as a result of heroin contamination.
What are the 2 most common organisms causing food poisoning?
1) Bacillus cereus
2) Staph. aureus
What is the key carrier of Yersinia enterocolitica?
Pigs (undercooked/raw pork)
How long does bacillus cereus typically take to resolve?
<24h
Mx of giardiasis?
Metronidazole (or tinidazole)
When is the rotavirus given?
2 doses are required
3 months & 4 months old
1st line laxative in constipation?
Bulk forming e.g. ispaghula husk
What are 5 complications post-gastroenteritis?
1) lactose intolerance
2) IBS
3) HUS
4) reactive arthritis
5) Guillain-Barre
What are 2 key causes of reactive arthritis?
1) GI infection e.g. Campylobacter
2) Urogenital infection e.g. Chlamydia
3 key features of reactive arthritis?
1) Arthritis
2) Urethritis
3) Conjunctivitis
How long after initial infection does reactive arthritis typically develop?
4 weeks
What is Guillain-Barre symdrome classically triggered by?
Infection by Campylobacter jejuni
What is Guillain-Barre syndrome?
An immune mediated demyelination of the peripheral nervous system often triggered by an infection.
What is the characteristic feature of Guillain-Barre?
Progressive weakness of all 4 limbs.
Describe the weakness in Guillain-Barre
Classically ascending (i.e. the lower extremities are affected first).
However, it tends to affect proximal muscles earlier than distal ones.
Mx of Guillain-Barre?
1) plasma exchange
2) IV immunoglobulins
How does DKA affect potassium levels?
Well known cause of HYPOkalaemia (due to osmotic diuresis).
What are the 4 principles of DKA management?
1) Fluid replacement (0.9% saline)
2) Fixed rate insulin infusion (0.1 units/kg/hr)
3) Correction of electrolytes
4) Stop short acting insulin, continue long acting
What are the 3 most common precipitating factors of a DKA?
1) Infection
2) Missed insulin doses
3) MI
Blood ketone levels in DKA?
<0.6 mmol/L –> normal (indicates DKA resolution)
> 3 mmol/L –> indicates DKA
What is the DKA resolution level for blood ketones?
<0.6 mmol/L
What is the DKA resolution level for bicarb?
> 15 mmol/L
When should dextrose 10% be added to fluid replacement in DKA management?
Once blood glucose is <14 mmol/L
Pathophysiology of DKA?
1) Insulin deficiency
2) Increased glucose production by liver
3) Decreased peripheral glucose utilisation & enhanced lipolysis
4) Subsequent ketone formation (ketones can cross BBB)
Key points for DKA diagnosis for:
a) glucose
b) pH
c) bicarb
d) ketones
a) >11 mmol/L OR known diabetes
b) <7.3
c) <15 mmol/L
d) >3 mmol/L (blood) OR urine ketones ++ on dipstick
Why can DKA increase the risk of VTE?
Combination of dehdyration, immobility & hypercoaguable state.
What are 3 key iatrogenic complications of DKA management?
1) Cerebral oedema
2) Hypokalaemia
3) Hypoglycaemia
Investigation of suspected cerebral oedema?
CT head and urgent senior review
How does alcohol lead to hypoglycaemia?
Due to its inhibitory effects of gluconeogenesis and glycogenolysis.
Blood glucose levels below what level causes autonomic symptoms?
<3.3 mmol/L
What is Whipple’s triad?
To aid diagnosis of hypoglycaemia:
1) Low blood glucose
2) Signs and symptoms suggestive of hypoglycaemia
3) Resolution of symptoms w/ correction of blood glucose
Relationship between GH and glucose?
GH causes increase in blood glucose.
Raised blood glucose then inhibits GH (negative feedback).
What is an insulinoma?
Neuroendocrine tumour of pancreas - causes unregulated secretion of insulin.
What 3 hormones increase glucose levels?
1) Glucagon
2) GH
3) Cortisol
What is the most common autonomic feature of hypoglycaemia?
Sweating
Who is glucagon ineffective in in hypogylcaemia? Why?
Glucagon stimulates the conversion of STORED glycogen within the liver into glucose.
As a result, glucagon is ineffective in patients with DEPLETED glycogen stores (e.g. elderly patients with poor oral intake and patients with eating disorders).
What can recurrent episodes of hypoglycaemia lead to?
Hypoglycaemic unawareness
What is idiopathic postprandial syndrome (pseudohypoglycaemia)?
A rare condition that presents with symptoms of hypoglycaemia after ingesting a meal, with a normal blood glucose level.
What is hypoglycaemia unawareness?
Patients don’t develop the autonomic symptoms of low blood glucose.
What is the role of diazoxide?
Used to treat persistently low blood sugar levels caused by the body producing too much insulin.
Role of hypotonic solutions (e.g. 0.45% NaCl)?
Causes fluid to move from intravascular to intracellular space.
Role of hypertonic solution?
Causes fluid to move from intracellular to intravascular space.
Example of hypertonic solution?
3% saline
What is hypertonic solution used to treat? (2)
1) Severe hyponatraemia
2) Cerebral oedema
What do serum c-peptide levels indicate?
Reflects insulin levles.
A low level indicates that the pancreas is producing little/no insulin.
How is serum osmolarity affected in HHS?
Significantly raised serum osmolarity (typically > than 320 mosmol/kg), resulting in hyperviscosity of blood.
What are the 3 key features of Campylobacter infection?
1) prodrome: headache malaise
2) diarrhoea: often bloody
3) abdominal pain: may mimic appendicitis
What is the most common cause of pseudomembranous colitis?
C. diff infection
Incubation period of gastroenteritis caused by Staph. aureus?
30 mins to 8 hours
Which organism causing gastroenteritis presents with severe vomiting (but often no diarrhoea)?
Staph. aureus
What is the most common cause of peritonitis 2ary to peritoneal dialysis?
Staph. epidermis (coagulase negative, gram positive)
What is peritoneal dialysis?
A form of renal replacement therapy
What is a key complication of peritoneal dialysis?
Peritonitis
Key ECG features of hyperkalaemia?
1) Peaked T waves
2) Loss of P waves
3) Broad QRS complexes
4) Sinusoidal wave pattern
Who does Pseudomonas aeruginosa commonly cause chest infections in?
CF
what may fundoscopy reveal in HHS?
Papilloedema
What is pseudogout?
A crystal arthropathy involving the deposition of calcium pyrophosphate crystals in the joints.
This causes joint pain & erythema
Features of joint fluid under microscope in pseudogout?
Calcium pyrophosphate precipitates are seen as positively birefringent rhomboid-shaped crystals under microscopy
What are some risk factors for pseudogout?
1) Increasing age (key risk factor)
2) Haemochromatosis
3) Hyperparathyroidism
4) Low magnesium, low phosphate
5) Acromegaly
6) Wilson’s disease
What investigation is required in pseudogout?
aspiration of joint fluid, to exclude septic arthritis
Who are the majority of cases of malignant otitis externa seen in?
Diabetes mellitus
What is the HbA1c target for patients on lifestyle + metformin for management of diabetes?
48 mmol/mol
What is the HbA1c target for patients on any drug which may cause hypoglycaemia (e.g. lifestyle + sulfonylurea)?
53 mmol/mol
In patients who are on metformin only for their diabetes, at what threshold should you consider adding a second agent?
58 mmol/mol
What HbA1c level indicates poorly controlled diabetes (and therefore the need for a VRII in peri-operative period)?
≥69 mmol/mol
