Viva · IR system
Hepatobiliary Viva Questions
Oral-exam style questions and answers on hepatobiliary for MD, DNB and super-specialty practical examinations. Each answer links back to the playbook or Library entry it was written from.
- Why are prophylactic antibiotics required for routine biliary drain exchange?
- Indwelling biliary catheters are usually colonized, particularly internal–external drains that communicate with bowel. Manipulation and contrast injection can produce bacteremia or cholangitis, so intravenous prophylaxis is recommended even for routine exchange.
- What is the commonest cause of bile leaking around a biliary catheter?
- The usual causes are catheter occlusion, kinking or retraction with one or more side holes outside the biliary tree. The catheter should be assessed fluoroscopically and exchanged, repositioned or selectively upsized rather than treating the skin leakage alone.
- How do you prevent loss of access during biliary drain exchange?
- Completely release the locking loop and advance an exchange-length guidewire through the catheter into a stable intrahepatic duct or preferably into the small bowel before removing the catheter. Maintain continuous control of the wire and use a safety-wire or sheath-assisted technique when access is precarious.
- How will you manage a completely dislodged biliary drain?
- Assess tract age and urgently attempt fluoroscopic recanalization if the tract is mature. Gently cannulate the cutaneous opening with an angled catheter and hydrophilic wire, confirm intrabiliary position and replace the drain; obtain new ultrasound-guided access if the tract is immature, disrupted or cannot be safely recanalized.
- Where should the side holes of an internal–external biliary drain lie?
- Proximal side holes must lie within ducts upstream from the obstruction, the catheter should traverse the obstruction and the distal locking loop should lie freely within the duodenum or jejunum. No side hole should remain within the liver tract, peritoneum or subcutaneous tissues.
- When should a biliary drain be upsized?
- Upsizing is appropriate for recurrent sludge-related occlusion, viscous bile or persistent leakage after malposition and kinking have been corrected. Incremental upsizing, commonly by 2 Fr, is preferred because excessive dilation adds pain, bleeding and duct-injury risk.
- What does bright-red pulsatile blood from a biliary drain indicate?
- It suggests hepatic arterial injury such as a pseudoaneurysm or arterio-biliary fistula. The patient requires resuscitation and urgent angiography with selective transarterial embolization when active arterial bleeding is confirmed.
- What is the usual interval for routine biliary drain exchange?
- A practical interval is approximately 6–12 weeks, modified according to the catheter manufacturer, local protocol, catheter type and previous occlusion history. Patients with recurrent obstruction may require shorter intervals.
- What is the basic difference between percutaneous treatment of a benign and a malignant biliary stricture?
- A benign stricture is generally treated with balloon dilation and prolonged internal-external catheter drainage. An unresectable malignant stricture is usually treated with a self-expanding metal stent for durable internal palliation.
- Why should an uncovered metal stent not be routinely placed in a benign biliary stricture?
- It is permanent, becomes incorporated by epithelial and fibrous tissue, permits tissue ingrowth, and is difficult or impossible to remove. It may convert a potentially correctable benign lesion into chronic irreversible stent disease.
- How do you size the balloon for biliary stricture dilation?
- Size the balloon to the adjacent normal duct. Avoid more than approximately 20% oversizing for a native duct stricture; a fibrotic surgical anastomosis may tolerate approximately 20% to 30% oversizing.
- How do you size a malignant biliary metal stent?
- Use a diameter appropriate to the duct, commonly 8 to 10 mm for intrahepatic or hilar ducts and approximately 10 mm for the common duct. The stent should cover the tumor with at least 1 cm of normal duct beyond both ends.
- Which is better, a covered or an uncovered biliary metal stent?
- Neither is universally superior. Covered stents reduce tumor ingrowth and may be removable but have greater migration and side-branch occlusion risk; uncovered stents anchor well and preserve side branches but permit tumor ingrowth.
- When should both lobes be drained in malignant hilar obstruction?
- Both sides should be drained when one system does not decompress an adequate volume of viable liver, when both systems have been opacified or are infected, or when unilateral drainage cannot achieve the functional target. The practical goal is to drain more than 50% of viable hepatic volume.
- Why is a safety catheter left after metal stent placement?
- It preserves access, provides decompression, permits tamponade of minor bleeding, and allows immediate rescue if the stent is underexpanded, obstructed, or malpositioned.
- What are the technical endpoints of successful biliary dilation and stenting?
- The stricture is traversed, the balloon waist is abolished or substantially reduced, and contrast flows freely into bowel without major extravasation. For stenting, the lesion is completely covered, the stent is correctly positioned and expanded, and all intended functional segments drain.
- Why is a peripheral duct preferred over a central duct for initial puncture in PTBD?
- Peripheral ducts are farther from major hilar vascular structures, reducing the risk of arterial or portal venous injury, and provide a longer, more stable transhepatic tract for catheter fixation.
- What is the difference between external and internal-external biliary drainage, and why is internal-external preferred when feasible?
- External drainage diverts all bile outside the body via a catheter proximal to the obstruction, while internal-external drainage has side holes spanning the obstruction so bile can also flow into the duodenum. Internal-external drainage preserves enterohepatic bile salt circulation, improves nutrition and coagulation, and reduces fluid and electrolyte loss.
- A patient develops hematemesis and hemobilia three days after PTBD. What is your next step?
- First confirm catheter patency and hemodynamic stability, then perform a catheter cholangiogram or CT angiography to look for a pseudoaneurysm or arteriobiliary fistula, followed by hepatic angiography with selective embolization if a bleeding source is identified.
- What cutoffs for INR and platelet count are typically required before PTBD?
- An INR of 1.5 or less and a platelet count of at least 50000 per microliter are generally required, correcting with fresh frozen plasma, vitamin K, or platelet transfusion as needed before the procedure.
- In a patient with Bismuth type IV hilar cholangiocarcinoma, why might bilateral PTBD be preferred over unilateral drainage?
- Bismuth type IV involves both right and left hepatic duct systems with separation at the confluence, so unilateral drainage may leave a large volume of undrained, potentially infected liver; bilateral drainage maximizes the functional liver volume decompressed and reduces the risk of cholangitis in the undrained segment.
- Why should contrast injection be minimized during the initial cholangiogram in a patient with suspected cholangitis?
- Injecting contrast into an obstructed, infected biliary system under pressure can force bacteria and endotoxin into the bloodstream, precipitating bacteremia and septic shock; bile should be aspirated first and contrast injected slowly and sparingly.