Scar Wars Episode IV: A New Hope

Posted on April 14, 2012

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Huzzah!

I’m back after my spring hiatus! I haven’t posted since my GP placement, which was ages ago. Since then I’ve had a geriatrics elderly care placement at glorious Croydon University Hospital, and I’ve endured another six weeks of problem based learning. I’ve become obsessed with Temple Run and Draw Something on my iPad, discovered that Horrible Histories on CBBC is probably one of the most hilarious things on tv at the moment (whether you’re a twelve year old or not), and last night I went to the Mountbatten Festival of Music at the Royal Albert Hall. Turns out the Royal Marines Band Service can really play.

But now the Easter holiday is almost over, and so on Monday the adventure continues…

In the words of Papa Lazarou, “this is just a saga now”.

That’s right folks, I start surgery on Monday, and although I’m almost certain I’m not the Luke Skywalker of upper GI (I really consider myself more of a Yoda), I’m pretty sure it’s going to be quite good.

I always thought I’d like being a surgeon, with an acerbic wit even sharper than my scalpel. Honestly though, I’m pretty scared. I haven’t encountered many surgeons, but from what I’ve heard from colleagues who’ve already finished their surgery placements, they can be a pretty fierce breed and will take great pleasure in figuring out just how much you don’t know. On that note, I’ve decided today to revise the anatomy of the liver and gall bladder, in the hopes of setting the wards ablaze with my stellar performance on ward rounds. And by revise, I mean upload some drawings. Then I’ll ramble on a bit about gallstones, which get the award for the No 1 disease affecting the biliary tree. Congratulations.

You might be surprised to learn that the liver is an organ. And if that’s news to you, here’s another headline that might have passed you by: you can find your liver in your body.

LOBES vs SEGMENTS

The liver can be divided by lobes (left, right, caudate, quadrate) or by segments, of which there are loads. Liver lobes are formed from anatomical divisions, eg right and left saggital fissures. The right and left lobes, defined by the falciform ligament, are served by the right and left hepatic veins (which don’t communicate), which is useful if you want to do a lobectomy.

Additionally the liver can be divided into 8 hepatic segments, which themselves are individually served by secondary or tertiary branch of the portal triad, which allows surgical resection for segments that have sustained injury.

THE GALL BLADDER AND BILIARY TREE

The gall bladder concentrates bile, and acts as a bile reservoir. It’s found at the mid clavicular line on the left side, at the costal margin (hence, Murphy’s sign). It lies in the fossa between the right and the quadrate lobes of the liver. The gall bladder can be divided into the fundus, body and neck.

The biliary tree start with the right and left hepatic ducts, which join to form the common hepatic duct, and this joins with the cystic duct (which itself comes from the gall bladder) to form the common bile duct. The hepatopancreatic ampulla (Ampulla of Vater) is formed by the union of the common bile duct and the pancreatic duct, and is located at the major duodenal papilla, where the contents of the billiary tree are emptied in to the duodenum (specifically the second part of the duodenum). The sphincter of Oddi controls emptying into the duodenum at the major duodenal papilla (NB cholecystokinin, CCK relaxes the sphincter of Oddi).

Blood supply of the gall bladder:

Arterial supply is by the cystic artery, a branch of the right hepatic artery (part of the celiac trunk).

Venous drainage is directly to the sinusoids of the liver.

Gallstones

Stones formed inside the biliary tree.

Epidemiology

Increasing incidence, more common in women. 15% in over 60s. Higher incidence in black/asian people, so the 5 F’s (Female, fat, fertile, forty, fair) aren’t so accurate after all.

Unknown aetiology- thought that bile becomes “supersaturated” with cholesterol, and this precipitates stone formation: Admirand’s Triangle:

With increased percentage of bile salts and increased percentage of phospholipids, you get a decrease in percentage of cholesterol, so less chance of forming gall stones.

Risk factors

5 “F’s” – Fat, Forty, Female, Fertile, Fair (useful, but not totally accurate, see epidemiology).

Think lifestyle! High fat/cholesterol diet, obesity.

Other conditions- Haemolytic states, loss of terminal ileum eg in Crohn’s disease.

Drugs? COCP

Types of Stones

1. Mixed stone (80%)

2. Cholesterol (15%)

3. Pigment (5%), associated with haemolytic states

Complications depend on where they lodge:

In the Gall bladder

Biliary colic

Blockage at cystic duct. Symptoms: RUQ pain, especially after fatty meal. Pain may radiate to epigastrium and right scapula, +/- sweating, nausea, dyspepsia and occasionally vomiting.

Biliary colic isn’t a true colic- with a true colic you get waxing and waning pain with contractions, but in biliary colic, get a rise in pain, then a pain plateau, which can last hours, and then a decrease in pain. Murphy’s sign? not always with biliary colic- Get positive murphy’s sign more often with acute cholecystitis, where there is increased tenderness generally.

Acute Cholecystitis

Obstructed gall bladder plus infection. Patient will be more unwell, similar pain pattern to biliary colic. Pt will be systemically unwell, maybe with fever, will be tender and have a positive Murphy’s sign.

In Biliary tract

Obstructive jaundice, infection (ascending cholangitis), pancreatitis.

With an obstructive jaundice, ask about pale stools, dark urine, and jaundice (late). If you’ve found an obstructive jaundice on LFTs, want to rule out cancer- particularly cholangiocarcinoma and cancer of pancreas (esp head of pancreas).

Outside biliary tract

Gallstone Ileus. A large stone fistulates into the first part of the duodenum, to cause a small bowel obstruction.

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