Gastroenterology Flashcards
Which antibiotic is most strongly associated with Clostridium difficile infections?
Clindamycin
What is ranitidine?
H2 receptor antagonist
What is the MELD score?
The Model for End-stage Liver Disease (MELD) score
A cirrhosis severity scoring system that predicts three-month survival
What is the Child-Pugh score?
A method of determining prognosis in liver disease, particularly cirrhosis
Which clinical features suggest decompensation of cirrhosis?
Jaundice
Ascites
Variceal haemorrhage
Hepatic encephalopathy
What causes ascites in liver disease?
Portal hypertension rather than hypoalbuminemia
Why do patients with liver disease have hypoalbuminemia?
The liver produces albumin
How is hepatic encephalopathy treated?
Lactulose
How does lactulose work in hepatic encephalopathy?
lactulose is converted to lactic acid by intestinal flora → acidification in the gut leads to conversion of ammonia (NH3) to ammonium (NH4+) → ammonium is excreted in the faeces → decreased blood ammonia concentration
What is the function of bile?
Absorption of fat and fat-soluble vitamins
What is Reynold’s pentad?
Ascending cholangitis
- RUQ pain
- Jaundice
- Fever
- Shock (low BP, tachycardia)
- Altered mental status
What is the most common benign tumour of the kidney?
Angiomyolipoma
What is a Sister Mary Joseph nodule?
Palpable nodule bulging into the umbilicus as a result of metastasis of malignant cancer in the pelvis or abdomen
What is emphysematous cholecystitis?
Infection of the gallbladder with gas-forming bacteria
Air is found in the gallbladder wall or lumen
What is the most common renal malignancy in adults?
Renal cell carcinoma
What is the triad of renal cell carcinoma?
- Haematuria (most common)
- Flank pain
- Palpable flank pass
Only 5-10% of patients present with all three components of the triad
What is the major complication of rapid paracentesis?
Paracentesis-induced circulatory shock
Fast reaccumulation of ascites
Hyponatremia
Renal impairment
Impaired survival
How does alpha-1-antitrypsin deficiency affect the liver?
Impaired secretion of alpha-1-antitrypsin by hepatocytes → intracellular accumulation of alpha-1-antitrypsin → hepatocyte destruction → hepatitis and liver cirrhosis
Which two antibiotics can be used for C. diff infection?
Metronidazole
Vancomycin (severe disease)
Only time when oral vanc is used. Vanc is not absorbed by the GI but stays in the large bowel where it can kill C diff
Which biomarkers can be used to diagnose and monitor IBD?
Faecal calprotectin and lactoferrin
What is cholelithiasis?
Gallstones
What is cholecystitis?
Inflammation of the gallbladder
What is cholangitis?
Infection of the biliary tree
What are the risk factors for cholelithiasis?
Fat, Female, Fertile (multiple children or pregnant), Forty (or older), Fair-skinned, Family history
6 F’s
What is charcot’s triad for cholangitis?
- Abdominal pain
- High fever
- Jaundice
What is the most common cause of Budd-Chiari syndrome?
Polycythemia vera
What is Budd-Chiari syndrome?
Hepatic venous obstruction → hepatomegaly, ascites, abdominal discomfort
What is the most important risk factor for AAAs?
Smoking
Also advancing age, atherosclerosis, hypercholesterolaemia, hypertension
Where is splenic pain referred to?
Left shoulder
What is McBurney’s sign?
Point tenderness in the area one-third of the distance from the right anterior superior iliac spine to the umbilicus
Suggests appendicitis
What is Rovsing’s sign
Deep palpation of the LLQ causes RLQ pain
Appendicitis
What is the psoas sign?
RLQ pain with extension of the right leg against resistance
Appendicitis
What is the obturator sign?
RLQ pain with flexion and internal rotation of the right leg
Appendicitis
Name 3 of the most common organisms found in abdominal sepsis from the stomach or duodenum
1. Streptococcus
- Candida
- Lactobacilli
- Fungi
* Aerobic species predominate*
Name 3 of the most common organisms found in abdominal sepsis from the bowel and appendix
1. E. coli
2. Bacteroides fragilis
- Clostridium
- Peptostreptococcus
- E. faecalis
Anaerobes predominate
Which 3 organisms are most commonly responsible for cholecystitis?
- E. coli
- Klebsiella
- Enterococcus
Bowel ischaemia dramatically increases the risk of sepsis from which organism?
Clostridium
What do Cullen’s and Grey Turner’s signs suggest?
Retroperitoneal bleeding
Non-specific and sensitive sign of haemorrhagic pancreatitis, but associated with a poor prognosis
Also ruptured or leaking AAA
An increased proportion of immature neutrophils in the blood is known as a right or left shift?
Left shift
What type of nociceptors are most commonly involved in visceral pain and what stimulates them?
Mechanoreceptors
Stimulated by stretch
What type of nociceptors are most commonly involved in somatic pain and what stimulates them?
Chemoreceptors
Stimulated by blood or inflammatory cytokines
What electrolyte abnormality is found in pancreatitis?
Hypocalcaemia
Lipase breaks down peripancreatic and mesenteric fat → release of free fatty acids that bind calcium →hypocalcaemia
What is the most common cause of acute pancreatitis?
Gallstone
Distal to the ampulla of Vater, impeding the flow of pancreatic secretions
Which organs are retroperitoneal?
SAD PUCKER
S: suprarenal (adrenal) gland
A: aorta/IVC
D: duodenum (second and third part)
P: pancreas (except tail)
U: ureters
C: colon (ascending and descending)
K: kidneys
E: (o)esophagus
R: rectum
What are the pancreatic enzymes?
Lipase
Amylase
What type of inguinal hernia herniates lateral to the inferior epigastric vessels?
Indirect
Which type of inguinal hernia involves protrustion of tissue through the internal inguinal ring, external inguinal ring and into the scrotum
Indirect inguinal hernia
What are the boundaries of Hesselbach’s triangle?
Superior: inferior epigastric vessels
Lateral: inguinal ligament
Medial: rectus abdominis
What is the most common cause of large bowel obstruction?
Colorectal cancer
Where does pain from nephrolithiasis radiate?
Upper ureteral or renal pelvic obstruction: flank pain or tenderness
Lower ureteral obstruction: pain that may radiate to the ipsilateral testicle or labium
What is the most common type of renal calculi?
Calcium oxalate
Which type of renal calculi is radiolucent?
Uric acid
What are the risk factors for uric acid stones?
Gout and hyperuricemia
High purine diet
What causes struvite renal calculi?
Upper urinary tract infections with urease-producing bacteria
(Proteus mirabilis, Klebsiella,
Pseudomonas, Providencia, Enterobacter)
What are gallstones characteristically made of?
Cholesterol
What causes black gallstones?
Bilirubin
What is the characteristic US sign of appendicitis?
Target sign
Inflammation and oedema of the appendiceal wall causes hyperechoic and hypoechoic layers
What are the x-ray features of a SBO?
- Dilated loops of small or large bowel
- Air-fluid levels proximal to the obstruction
- Distal bowel collapse
- Minimal or no gas in colon
What are the x-ray features of a LBO?
- Air-fluid levels in the colon
- Bowel distention before obstruction
- Kidney bean/coffee-bean appearance of bowel e.g. volvulus
What are the xray features of a paralytic ileus?
- Uniform distribution of gas in the small bowel, colon and rectum
- Obliteration of the psoas muscle outline
Large: haustra
Small: valvulae conniventes/plicae circulares
What is the most common cause of lower GI bleeding in adults?
Diverticulosis
Draw the 9 regions of the abdomen
What is diverticulosis?
Asymptomatic diverticula
What is the definition of overwhelming post-splenectomy infection?
A bacterial infection that rapidly progresses to fulminant, overwhelming sepsis in the setting of anatomic or functional asplenia
When is the peak incidence of appendicitis?
10-19 years of age
What precipitates appendicitis?
Obstruction of the appendiceal lumen e.g. faecal material, undigested food, enlarged lymphoid follicle
Why do patients with appendicitis initially have diffuse periumbilical pain?
Obstruction of the appendiceal lumen stimulates mechanoreceptors (visceral)
What finding on a FBC is classical of appendicitis?
Mild leukocytosis with left shift
(not required for diagnosis)
Which antibody is most strongly associated with coeliac disease?
IgA anti-tissue transglutaminase
What is the classic x-ray finding of gastrointestinal perforation?
Free intraperitoneal air
Image: pneumoperitoneum secondary to PUD
Why might a urinalysis be performed when investigating appendicitis? What are the expected findings
Evaluate DDx e.g. acute UTI, nephrolithiasis
Mild pyuria may be present because of the close proximity between the right ureter and appendix
Where does subdiaphragmatic abdominal pain radiate?
Shoulder
What can cause hyperoxaluria?
Dietary: beets, beans, dark green vegetables
Vitamin C supplements
Bile malabsorption and/or chronic diarrhoea
Low calcium (calcium is required for oxalate absorption, and a decrease in absorption increases renal excretion)
What is more common, gastric or duodenal ulcers?
Duodenal (3:1)
What is the most common cause of peptic/duodenal ulcers?
H. pylori (80-90% of all ulcers)
What is the history of pain in patients with a perforated peptic ulcer?
Sudden onset, intense, stabbing pain followed by diffuse abdominal pain and distention
Which type of peptic ulcer is associated with weight gain?
Duodenal - pain is worst on an empty stomach
Which type of peptic ulcer is associated with weight loss?
Gastric ulcer
Pain is worst post-prandial
Which bacteria commonly causes mesenteric adenitis, mimicking appendicitis (pseudoappendicitis)?
Yersinia enterocoliticia
How long following the onset of appendicitis does perforation tend to occur?
After 72 hours of symptom onset
What is the most common cause of appendicitis in children?
Lymphoid hyperplasia
What is the most common cause of appendicitis in adults?
Faecalith
Other: fibrosis, neoplasia
What is Fitzhugh-Curtis syndrome?
Perihepatitis (extension of inflammation to the liver capsule and adjacent peritoneal surfaces)
Seen in PID
Right upper quadrant pain or pleuritic pain, no liver enzyme abnormalities
What findings are found on auscultation of a bowel obstruction?
Hyperactive “tinkling” bowel sounds early in the obstruction
Later bowel sounds are reduced or absent, often in combination with a markedly distended abdomen
Which cause of an acute abdomen classically has increased polymorphonucleocytes? (>75%, normal (50-65%)
Appendicitis
What is the “pointing sign”?
Patients will point to the spot of pain in peptic ulcer disease
A patient in pain and moving around unable to find a comfortable position is characteristic of which condition?
Renal colic
What imaging is used for diverticular disease?
Contrast enema and colonoscopy
What imaging is used for acute diverticulitis?
CT
What are some complications of diverticular disease?
Haemorrhage
Abscess
Perforation
Peritonitis
Fistula
Stricture
Obstruction
Which bile ducts does primary biliary cholangitis (PBC) affect?
Small intralobular bile ducts (part of the hepatic portal triad)
Which antibody test is most specific for primary biliary cholangitis (PBC)?
AMA (98%)
ANA also commonly positive
Which immunoglobulin tends to be raised in PBC?
IgM
Who gets primary biliary cholangitis (PBC)?
Middle aged women (95%)
35-60 years old
What is the classic presentation of primary biliary cholangitis (PBC)?
Usually asymptomatic and diagnosed based on deranged LFTs
If symptomatic:
- Fatigue
- Pruritis
- Skin hyperpigmentation/dryness
- Xanthelasma/xanthomata
- RUQ discomfort
Can progress to chronic liver disease (jaundice, hepatomegaly, portal HTN)
Which diseases are classicaly associated with primary biliary cholangitis (PBC)?
- Sjogrens (65-80% of people with PBC)
- Thyroid disease (10-15%)
- Limited cutaneous scleroderma (5-15%)
- Classic rheumatoid arthritis (5-10%)
What do you expect the LFTs to be in a patient with primary biliary cholangitis (PBC)?
Cholestatic picture
ALP > 1.5 upper limit of normal
Mild transaminitis (elevated AST and ALT)
How are patients with primary biliary cholangitis (PBC) treated?
Ursodeoxycholic acid
Supportive for itch: antihistamines, cholestyramine
What screening should you do in a patient with primary biliary cholangitis (PBC)?
TSH - annual
Lipids
DEXA - 6 months
Vitamin D (A and K also if bilirubin > 20) - annual
What can misoprostol be used for in gastroenterology?
Peptic ulcer disease
Prostaglandin analogue → increases mucous secretion
When might bilirubin be positive on urinalysis?
Failure of conjugated bilirubin to reach the intestines → bilirubin is not converted to urobilinogen
Biliary obstruction
Hepatic disease; hepatocellular disease, cirrhosis, hepatitis
What might cause an elevated urobilinogen on urinalysis?
Conjugated hyperbilirubinaemia; extravascular haemolysis, malaria
Impaired hepatic reabsorption of urobilinogen; liver disease
Absent or decreased in obstructive jaundice
What causes steatorrhoea?
Pancreatic e.g., chronic pancreatitis, CF
Malabsorption e.g., coeliac, giardiasis, Whipple’s disease, Crohn’s
Biliary e.g., PBC, PSC
What are the two main diagnostic laboratory tests for coeliac disease?
IgA anti-tissue transglutaminase antibody
IgG deamidated gliadin peptide (test of choice for children < 2)
Do perianal fistulae or abscesses suggest UC or CD?
Crohn’s disease
What are the classic features of IBS?
ABC
A - abdominal pain
B - bloating
C - change in bowel habit
How is portal hypertension identified as the cause of a patient’s ascites?
A serum-to-ascites albumin gradient (SAAG) > 11g/L
Requires paracentesis
What extraintestinal manifestation of IBD is common in UC but not CD?
Primary sclerosing cholangitis
What are the adverse effects of PPI use?
N&V, constipation, diarrhoea
Hypomagnesemia (malabsorption)
Hypocalcemia (malabsorption)
Low B12 (malabsorption)
Increased risk of C. diff
Speculation: pneumonia, CKD progression, fractures
In which part of the intestines is the B12-intrinsic factor complex absorbed?
Distal ileum
