Surgical Conditions of the Spleen, Liver, and Extrahepatic Biliary System Flashcards
(117 cards)
1
Q
What is the most common malignancy in the spleen?
A
- Hemangiosarcoma
2
Q
What are other splenic malignancies besides hemangiosarcoma?
A
- leiomyosarcoma, osteosarcoma, fibrosarcoma, undifferentiated sarcoma, lymphosarcoma, plasma cell tumor, mast cell tumor
3
Q
What are three common benign masses in the spleen?
A
- Hemangioma
- Nodular hyperplasia
- Hematoma
4
Q
Can you tell the difference between the most common malignant splenic mass and the common benign splenic masses via gross appearance or cytology (i.e. without histopathology)?
A
You cannot
5
Q
Odds that a splenic mass is benign or malignant if found incidentally or was a mass that has not bled
A
- 30% malignant
- 70% benign
6
Q
Odds that a splenic mass is malignant if ruptured and caused a hemoabdomen?
A
- 2/3 are malignant
- 1/3 are benign
7
Q
Dfdx for liver nodules
A
- Mets from splenic neoplasia
- Extramedullary hematopoiesis
- Nodular hyperplasia
- Primary liver neoplasia
8
Q
Can you tell apart grossly whether a splenic mass is benign or malignant?
A
- You cannot
9
Q
Can you differentiate on cytology splenic HSA, hemangioma, and hematoma?
A
- You cannot
10
Q
Which breed has an increased incidence of HSA?
A
- German SHepherds
- More common in large than small breed dogs
11
Q
Most common primary sites for HSA
A
- Spleen
- Right atrium and auricle
12
Q
Metastatic rate for HSA
A
- High
13
Q
Where does HSA met?
A
- Liver, omentum, and lung
14
Q
Thus, a pre-op plan for patient with potential splenic HSA should include what diagnostics?
A
- Advise echocardiogram
- Thoracic radiographs
- Abdominal ultrasound
15
Q
Survival time for splenic mass if benign
A
- Surgery is curative
16
Q
Survival time for HSA mass with splenectomy alone and with chemotherapy
A
- 1-3 months with splenectomy alone
- 3-12 months with splenectomy and chemotherapy
17
Q
What should you do when you diagnose a splenic mass but don’t yet know what kind it is an need to advise the owners?
A
- Advise that while malignant splenic masses like hemangiosarcoma have a poor prognosis, some other splenic masses can be cured via splenectomy
18
Q
If you see hepatic nodules in a dog with a splenic mass (or any other mass), does that mean that metastasis has for sure occurred?
A
- NO
19
Q
How can splenic torsion occur?
A
- The spleen can rotate around its vascular pedicle, obstructing venous drainage, leading to splenomegaly, congestion, and possible thrombosis, strangulation, necrosis, or sepsis
20
Q
How does splenic torsion occur most commonly?
A
- In large, deep chested dogs and while it is often associated with GDV, it can occur isolated
21
Q
Is a splenic torsion an emergency?
A
- YES
22
Q
Should you untwist the spleen prior to removal?
A
- DO NOT to avoid reperfusion
23
Q
Indications for splenectomy
A
- COnfirmed splenic neoplasia
- Splenic mass for which neoplasia is a main ddx
- Splenic mass (benign or malignant) that has bled significantly or is at risk of bleeding (treat hemoabdomen medically until patient is stabilized if possible)
- Splenic torsion
- Severe trauma to spleen with uncontrolled bleeding or necrosis (most traumatic bleeds from spleen can be managed medically)
- +/- immune mediated disease
24
Q
Consequences of spleen removal in dogs
A
- Lack of spleen is tolerated very well in dogs with minimal consequences
25
Ligations - what direction for splenectomy?
- Usually from tail to head of spleen
- Splenic artery
- Then left gastroepiploic artery
- then short gastric artery
26
Ligation options for splenectomy
- Suture, clips, and/or special cautery units like ligasure
27
Which branches of the main splenic artery and vein should you preserve?
- those to the left lobe of the pancreas
28
What do you ligate the main splenic artery with?
- Silk suture
29
For smaller vessels, what can you ligate vessels with?
- Suture
- Metal clips/suture
- Ligasure (sophisticated electrocautery)
30
How can compromised liver function impact your surgical patient (6 primary reasons)
a. Decrease in compounds made by the liver such as albumin, glucose, and decrease in clotting factors needed for hemostasis
b. Neurological signs due to hepatic encephalopathy
c. Difficulties with drug metabolized by the liver (e.g. barbiturates, phenothiazines)
d. Difficulties with drugs that are protein bound (e.g. diazepam)
e. Anemia (due to nutritional deficiencies, coagulation abnormalities, or GI hemorrhage)
f. Coagulopathy
31
What should you do before performing a biopsy (percutaneous or intra-op) of potentially vascular tissue (e.g. liver, spleen, kidney, neoplasia) and before doing surgery in a patient with liver disease to make sure it is safe?
- Coagulation tests (PT/PTT)
32
Blood supply to the liver
25% via hepatic artery (25%)
75% via portal vein (75%)
33
Which of the vessels (hepatic artery or portal vein) is required for life?
- Portal vein
34
Name the 6 lobes of the liver from left to right
- Left lateral, left medial, quadrate, right medial, right lateral, caudate process of the caudate lobe
35
Which lobe has two processes? Name the lobe and the processes
- Caudate lobe - caudate and papillary process
36
Where is the gallbladder relative to the lobes of hte liver?
- Quadrate process and right medial liver lobe
37
Guillotine technique for liver biopsy
- Suture cuts through parenchyma and settles on vessels and bile ducts, ligating these structures
38
What do you fill the biopsy hole with if you use a dermal biopsy punch?
- Gelfoam which serves as a framework for clot formation
39
Describe guillotine with transfixation liver biopsy technique
- Make two 2mm nicks in the edge of the liver with Metzenbaums
- Back the needle through the liver
- Tighten in one notch with two throws
- Tighten in the other notch with 4 throws
- Biopsy the piece
40
How can you slow severe bleeding from the liver intraoperatively?
- Manually hold off the hepatic artery and portal vein where they are accessible along the ventral border of the epiploic foramen (Pringle maneuver)
41
Non-neoplastic condition dfdx for a liver mass
1. Extramedullary hematopoiesis
2. Nodular hyperplasia
3. Cyst (if symptomatic, resect/drain/omentalize)
4. Abscess (tx includes antibiotics, resect/drain/omentalize)
42
Dfdx and prognosis for neoplastic conditions in the liver
1. Hepatocellular adenoma (curable with surgery!)
2. Hepatocellular carcinoma (if localized, can survive >1 year postop)
3. Bile duct carcinoma (high metastatic rate, poor prognosis)
43
Diagnostic plan for working up a patient with a liver mass
- We didn't fill it out
- I think CBC/Chem/UA
- Thoracic radiographs
- Abdominal Ultrasound
- FNA or biopsy of the liver
- PT/PTT
44
Liver surgery - who does it?
Experienced surgeons only
45
Which bacteria to target for liver surgery?
- Gram negative aerobes and anaerobes
46
How much of hte liver can you remove and still get regeneration by hypertrophy and hyperplasia back to normal liver mass in 6 weeks in a healthy dog?
- 70-80% of the liver
47
How are liver lobes most commonly removed?
- WIth a stapling device
48
What abdominal organs drain into the portal vein?
- Go back to applied anatomy notes I think
49
What route does blood in the portal vein take to get back to the systemic system
- Go back to applied anatomy notes but definitely do it
50
What is the purpose of the portal system?
- Drain blood from the abdomen (GIT, pancreas, spleen) through the liver, where endogenous and exogenous toxins can be removed
51
What abdominal organs drain directly into the systemic system?
- Review this from applied anatomy when you get a chance
52
What is a portosystemic shunt?
- Aberrant vein that shunts blood from the portal system to the systemic venous circulation
53
Why does bloood go through the PSS?
- A drop of blood approaching the PSS has two choices - it can go through the pSS to the systemic circulation (little resistance) or go through the portal vein to the liver (higher resistance due to sinusoids)
54
What type of shunts do small breed dogs get?
- Single, congenital, extra-hepatic, macroscopic shunts
55
What type of shutns do large breed dogs get?
- Single, congenital, intra-hepatic, macroscopic shunts
56
What type of PSS do cats get?
- Single, congenital, extra-hepatic, macroscopic
57
What type of shunts are associated with hepatic fibrosis?
- Multiple, acquired, extra-hepatic, macrosopic shunts
58
What type of shunts are associated with hepatic microvascular dysplasia or portal vein hypoplasia?
- Multiple, congenital, intra-hepatic, microscopic shunts
59
How does hepatic fibrosis lead to shunts?
- Liver disease that leads to fibrosis results in increased resistance to blood flow in the liver --> body opens up hundreds of little extrahepatic vessels that act as PSSs to accommodate blood that can't get into the liver - you can see the nests of vessels when doing an abdominal explore
60
Hepatic microvascular dysplasia or portal vein hypoplasia - what's the difference?
- Two terms for the same condition
61
Can HMD or PVH be treated surgically?
- No; support with medical management
62
Clinical appearance of dogs with HMD or PVH?
- Look the same as dogs with macroscopic PSS
63
HMD and PVH in certain liver lobes
- Can be in some liver lobes and not others (so we typically biopsy multiple liver lobes when looking for HMD/PVH)
64
What do clinical signs in PSS reflect?
- Liver compromise and hepatic encephalopathy
65
Clinical signs in PSS
- Poor doer
- Smaller than litter mates
- GI signs (V/D)
- Neuro signs (seizures, head pressing)
- COpper colored eyes
- Ptyalism
66
PSS labwork
- Microcytosis
- Low normal to decreased glucose
- Low normal to decrased albumin
- Low normal to decreased cholesterol
- Low normal to decreased BUN
- Increased ammonia
- Presence of ammonium biurate crystals
- Increased ALT and ALP
- Increased Bile acids
67
What leads to increased ALT and ALP in PSS?
- Small, underperforming liver
68
Pathophys of microcytosis with PSS
- Small underperforming liver has decreased iron handling
69
Pathophys of low normal to decreased glucose/albumin/cholesterol with PSS
- Small and underperforming liver leads to decreased synthetic processes
70
Pathophys of low normal to decreased BUN with PSS
- Small and underperforming liver leads to decreased ammonia metabolism
71
Pathophys of increased ammonia and ammonium biurate crystals with PSS
- Small and underperforming liver leads to decreased ammonia metabolism
72
What leads to increased bile acids with PSS?
- GIT blood direct to systemic circulation
| - Increased bile acids
73
Imaging of PSS and findings
1. Abdominal rads: main finding is microhepatica
2. AUS: small liver; experienced radiologist can often find PSS
3. Abd CT: small liver; often very good way to find PSS itself
4. May find bladder stones
74
What bladder stones are associated with PSS?
- Urate
75
Intraop imaging - when to do?
- Only if you can't find PSS on abdominal explore
| - It's a portogram
76
How to do a portogram?
- Contrast injected into portal system via jejunal vein or splenic injection
- Shows flow of blood through PSS as well as contrast appearing in the heart before the liver
77
Medical management of PSS
- Diet change
- Lactulose
- Antibiotics
- Levetiracetam or Keppra
78
What diet for PSS?
- Protein restricetd diet, higher levels of branched chain amino acids
79
Lactulose - why for PSS?
- Decreases time ingesta is in the colon and is acidic so helps keep NH4+ in lumen rather than being absorbed
80
Antibiotics for PSS - why?
- Decrease colonic flora that make ammonium
| - Primary type are gram neg anaerobes
81
Which antibiotics work against gram neg anaerobes?
- Ampicillin
- Metronidazole
- Neomycin
82
Why levetiracetam for PSS?
- Decrease risk of seizures post-op (start Keppra 24 hr before and go for 2 weeks)
83
Treatment of single intrahepatic or extrahepatic PSS
- Surgical treatment if done by an experienced surgeon
| - An ameroid constrictor or cellophane is placed around the PSS
84
How do ameroid constrictors or cellophane close PSS?
- Swelling of casein in the ameroid constrictor or inflammation caused by the cellophane results in occlusion of the shunt over several weeks
85
Why is the gradual closure of the PSS so important?
- It gives the liver time to adjust to the increase in blood flow that occurs as teh shunt is closed down and blood has to go back through the portal system
86
What are complications that could occur immediately after (in the first week) PSS surgery?
- Portal hypertension
| - Intractable status epilepticus
87
Long-term complications with PSS
- pre-existing hepatic microvascular dysplasia/portal vs hypoplasia
- Second surgery if PSS doesn't fully close
- Develop multiple extrahepatic shunts
88
What happens if the PSS clsoes too fast?
- you can get acute portal hypertension where the PSS gets occluded abruptly by a thrombus or kink in teh ameroid constrictor, the liver can't accommodate the redirected blood
- Blood backs up into the organs that feed into the portal system
89
What are some sequelae of portal hypertension?
- Severe congestion of the GIT occurs, with abdominal pain, ascites, melena, and ultimately death
90
Treatment for portal hypertension
- Intensive care and possible emergency surgery
91
Perioperative mortality for extrahepatic vs intrahepatic shunts?
- 5-20% for extrahepatic
| - Intrahepatic is >25%
92
What can happen if the liver can't accommodate redirected blood as the PSS gradually closes?
- Multiple extrahepatic shunts will develop
93
Prognosis for surgical correction of congenital PSS vs medical?
- Patients treated surgically for congenital PSS lived longer, had less ongoing clinical signs, and less need for medication than dogs treated medically
94
Post-surgery medical management and tapering after PSS surgery
- Taper off medicine to a degree possible
| - Some liver dysfunction can remain, requiring some amount of diet or medical management for life
95
Review: Trace the flow of bile from the liver to the gallbladder to the intestine
- Maybe in applied anatomy notes?
96
What are the three main causes of icterus?
- Pre-hepatic (hemolysis)
- Hepatic
- Post-hepatic
97
Ddx for extrahepatic bile duct obstruction (4)
1. Pancreatic disease
2. Cholelithiasis
3. Neoplasia (within or outside of the bile duct)
4. Biliary mucocele
98
What is a biliary mucocele
-Extra mucus from hyperplasia of mucus-secreting glands in gallbladder mucosa results in bile so thick it cannot empty from the gallbladder
99
POtential consequences of extrahepatic bile duct obstruction?
- Increased liver enzymes and bilirubin (incerased ALT, ALP, BR)
- Vitamin K deficiency
- Coagulopathy
- Bile peritonitis secondary to perforation/rupture
100
What are the four fat soluble vitamins?
- Not sure!
- Vitamin K appears to be one of them
- maybe in clin path and phys notes????
101
How do you absorb the four fat soluble vitamins?
- Not sure
| - notes from clin path or phys?
102
Why can a patient with bile duct obstruction have a coagulopathy even if the liver function itself is okay?
- Vitamin K is a fat soluble vitamin, and I guess it can't get into the intestine if there is a bile duct obstruction
- Without absorption of Vitamin K, the patient is at risk for coagulopathy
103
What is the bottom line of biliary surgery?
- Must maintain route for bile to get from liver to the intestine
104
What is the treatment for biliary mucocele and ruptured/necrotic gallbladder? (include procedure name)
- Remove gallbladder (cholecystectomy
105
What is the treatment for an unsalvageable common bile duct? (include procedure name)
- Must anastomose gallbladder to the intestine, a procedure called cholecystoenterostomy
106
Who should do biliary surgery, and where?
- Qualified surgeon in a facility where 24 hour intensive care is available
107
What is the responsibility of general practitioners with regards to biliary surgery?
1. Diagnose surgical conditions of the biliary tract so they can properly refer the patient
2. Explain to clients why their pet needs a given biliary surgery
3. Understand the anatomy of the biliary tree enough so that if you are in the abdomen, you recognize if there is a problem with the biliary tree and understand how bile flow has been changed by the aforementioned surgeries
4. Participate in the potentially lifelong management that may be needed after biliary rerouting, usually with the guidance of an internist
108
If you are in the abdomen and recognize there is a problem with the biliary tree, what can you do?
- Close and get the patient to a surgeon
109
What are four causes of bile peritonitis?
A. Necrotizing cholecystitis
B. Trauma to bile ducts
C. Neoplasia
D. Extrahepatic bile duct obstruction
110
When can a diagnosis f bile peritonitis be confirmed based on concentration of bilirubin in the abd fluid compared to serum bilirubin?
- Concentration of bilirubin in the abdominal fluid is 2x higher than serum bilirubin
111
Sterile bile in abdomen clinical signs and mortality?
- SUBTLE clinical signs
| - 0-13% mortality
112
How can sterile bile in the abdomen lead to septic bile peritonitis?
1. Bile salts irritate the peritoneum and serosa --> bacteria migrate across intestinal walls
2. Less bile in the intestine --> may increase endotoxin absorption
113
Signs of septic bile peritonitis
- Acute abdomen and shock
| - 55-73% mortality
114
What is the first choice for treatment of hemoabdomen due to hepatic trauma?
- Medical management
- Support patient and allow coagulation process to occur
- Treatment includes fluids, blood products, abdominal pressure, etc.
115
When is surgical management of hepatic trauma indicated?
- ONLY if medical management fails; hepatic lacerations/fractured lobes are hard to repair and surgery may only further compromise patient
116
What must you rule out before surgical management of hepatic trauma?
- Rule out coagulopathy (e.g. rodenticie ingestion, coagulation factor deficiency) as cause before going to surgery to treat a hemoabdomen (surgery can be fatal)
117
Who should do emergency surgery for liver trauma?
- An experienced surgeon
| - Treatment may require liver lobectomy or repair of the biliary system
