The Standard Drink


A “standard drink” is a measure of pure ethanol consumed. One standard drink represents 10 grams of pure ethanol.

This means that based on the alcohol percentage of certain drinks, the “standard” size changes. The important thing to be aware of is to think of it as a Standard Drink because the size that equals 10 g of ethanol isn’t necessarily the standard size that is served. This is why it’s a good habit when asking “how many glasses of _______ do you drink” to ask about the size of the glass.

This design was actually originally made for an event, but I’m reposting it here because it’s useful and I like it and I haven’t had a chance to draw anything new recently.

Gallbladder Disease (cholelithiasis, biliary colic, cholecystitis, choledocholithiasis, cholangitis)

A lot of the western world have stones in their gallbladders (cholelithiasis) but for the most part they just grumble along with no trouble at all.

  1. Cholelithiasis – Gallstones just hanging out, not causing any problems
  2. Biliary colic – happens after a fatty meal, the GB contracts and pushes stones into the cystic duct but when the duct relaxes the stone rolls back into the GB. The pain is entirely visceral and generally lasts <6h. There should be no fever or chills.
  3. Cholecystitis – inflammation of the GB. It’s biliary colic that just doesn’t go away. The pain lasts longer than 6h and is usually associated with nausea/vomiting, fever and right upper quadrant pain.
  4. Choledocholithiasis – gallstones in the common bile duct. Usually secondary to cholelithiasis, but can be a primary stone in cases of bile stasis or recurrent infection of the biliary tree. Usually have abnormalities in liver enzymes and pain but no fever.
    The 2 major complications are 1) Cholangitis and 2) Acute pancreatitis.
  5. Cholangitis – infection/inflammation of the biliary tree (infected bile or gallstone), secondary to an impacted stone or stricture(s).
    Do an ultrasound. Start antibiotics (common bugs are a mix of gram +/- and anaerobes = E. coli, enterococcus, bactericides). Ciprofloxacin or a combination of ampicillin, ceftazimide and metronidazole.
    Make sure that the person receives some fluid resuscitation to help with the hypoperfusion
    Charcot’s triad: fever, RUQ pain, jaundice
    Reynold’s pentad: hypoperfusion, decreased level of consciousness (SHOCK!!!)

    • Biliary leaks
    • Liver abscess
    • Infected choledochal cysts
    • Cholecystitis
    • Mirizzi syndrome
    • Right lower lobe pneumonia/empyema

Lab values

Biliary Colic Cholecystitis Choledocholithiasis Cholangitis Gallbladder Pancreatitis
WBC  –  ↑ ↑↑  ↑
AST  ↑
Total Bili  – ↑↑ ↑↑
Direct Bili ↑↑ ↑↑↑ ↑↑
ALP ↑↑ ↑↑↑ ↑↑
GGT ↑↑ ↑↑↑ ↑↑
Lipase ↑↑↑ (>3x)
Amylase ↑↑↑ (>3x)
Treatment Cholecystectomy Cholecystectomy ERCP +/- Cholecystectomy Fluid resuscitation ERCP + Cholecystectomy Fluid resuscitation ERCP + Cholecystectomy

Blood supply of the GI tract


Turns out there’s a lot of stuff in the abdomen. One could even say there’s almost as much as in the hand. Maybe.

There are three main trunks/arteries off the descending aorta that supply the blood to the guts.

  1. Celiac trunk – foregut (stomach to where the bile duct enters the duodenum)
    1. Common hepatic
      • Hepatic proper
        • Left hepatic
        • Right hepatic
      • Right gastric
      • Gastroduodenal
    2. Left gastric
    3. Splenic
  2. Superior mesenteric artery – midgut (from where the bile duct enters the duodenum to 2/3 across the transverse colon)
    1. Right colic
    2. Middle colic
    3. Ileocolic
    4. Ileal and jejunal branches
  3. Inferior mesenteric artery – hindgut (from 2/3 across the transverse colon to the rectum)
    1. Left colic
    2. Sigmoid
    3. Superior rectal


The stomach is needy and gets a pretty excellent blood supply, which makes remembering is a little tricky

  • Lesser curve: right and left gastric arteries
  • Greater curve: right gastroepipiloic/gastro-omental (off the gastroduodenal artery) and left gastroepipiloic/gastro-omental (off the splenic artery)
  • Fundus: short gastrics (off the splenic artery)

Merry Christmas!

Merry Christmas and happy holidays!

Now take a break from studying!

Calcium homeostasis, parathyroid and vitamin D

Calcium homeostasis is largely controlled by the parathyroid glands (tucked away underneath the thyroid). I’ve included a little bit of the vitamin D synthesis pathway as well, though D3 (the form that is absorbed in the intestines) is also synthesized in the skin as long as you’re getting a little bit of sunlight.


  1. Hyperparathyroidism: usually an adenoma
  2. Malignancy: PTH-related peptide released by tumor (squamous cell, renal, breast, bladder)
  3. Vitamin D excess: granulomas (sarcoidosis, TB, Wegener’s)
  4. Increased bone turnover: hyperthyroidism, Paget’s
  5. Familial hypocalcuric hypercalcemia: mutation in the calcium-sensing receptor in parathyroid and kidney


  1. Hypoparathyroidism: sporadic, caused by thyroid surgery, Wilson’s, hypomagnesemia
  2. Pseudo-Hypoparathyroidism: PTH end-organ resistance
  3. Vitamin D deficiency: no sunlight, GI disease
  4. Chronic renal failure: decreased 1,25(OH)D production, increased phosphate
  5. Calcium sequestration: acute phosphate increase

Liver Enzymes (hepatic vs cholestatic patterns)


Liver enzymes can be elevated for a number of reasons, but the first step in an approach is to determine if the enzymes are in a hepatic pattern or cholestatic pattern. It is also very important to realize that Alk phos, GGT, ALP, and AST are liver enzymes, but they don’t give an indication of function; for that you need to look at INR and bilirubin.

Z tracking for paracentesis

Z-tracking is a way to minimize fluid leakage after performing a paracentesis. The skin is slowly pulled down while the needle is advanced in 5 mm increments, aspirating as you go. If it is a therapeutic paracentesis, use a large bore needle (14) to reduce the amount of time it takes to drain.

Indications for paracentesis

  • New onset ascites
  • Hospitalization of a patient with ascites
  • Clinical deterioration of an inpatient or outpatient with ascites
    • Fever
    • Abdominal pain
    • Abdominal tenderness
    • Hepatic encephalopathy
    • Peripheral leukocytosis
    • Deterioration in renal function
    • Acidosis

Routine tests

  • Cell count and differential
  • Albumin concentration (you then compare this to serum albumin)
  • Total protein concentration
  • Culture


DIC, primary fibrinolysis

serum to aspires gradient (SAAG)

Used to identify the presence of portal hypertension

SAAG = Serum albumin – Ascites albumin

≥11 g/L: portal hypertension
<11 g/L: not portal hypertension
If heart failure is the cause, the gradient can be narrowed by diuresis, but in cirrhosis the gradient does not change unless the portal pressure drops significantly