The Diagnosis Challenge: Hepatobiliary System | Premed Projects

Summary

Purpose and Session Structure

Dr. Osama leads an introductory lesson on the hepatobiliary system, combining anatomy, physiology, medical imaging, clinical cases, and questions from student attendees. The session assumes no prior knowledge and uses an interactive quiz platform and anatomy illustrations.

Hepatobiliary Anatomy and Function

• The hepatobiliary system consists of the liver, gallbladder, and bile ducts.
• The liver lies mainly in the right upper abdomen and is the body’s largest solid organ. It has two main lobes and can also be divided into functional segments, each with its own blood supply.
• Blood reaches the liver through the hepatic artery and the hepatic portal vein. The portal vein carries blood from the digestive tract, allowing the liver to process absorbed substances before they enter the wider circulation. This is called first-pass metabolism.
• Liver functions discussed include:
  • Producing bile, which helps digest fats in the small intestine.
  • Making albumin, which helps keep fluid in blood vessels, and producing clotting factors.
  • Processing blood, nutrients, medicines, alcohol, and toxins.
  • Regulating blood sugar and amino acids, and storing vitamins and minerals.
  • Providing immune defense through specialized Kupffer cells.
• Hepatocytes are the liver’s main functional cells.
• The gallbladder stores bile made by the liver. Bile travels through the hepatic ducts, can enter the gallbladder through the cystic duct, and then passes through the common bile duct into the duodenum. Some bile can also flow directly toward the intestine.
• The pancreas lies near the bile ducts and releases digestive enzymes into the small intestine. The session also reviews the route through the digestive tract and the distinction between the small and large intestines.

Imaging and Anatomy Review

The presenter uses an anatomy application and scan examples to orient students to abdominal structures.

• CT uses X-rays to create cross-sectional images.
• MRI uses magnetic fields and is useful for imaging soft tissues, including the liver. Ultrasound uses sound waves and can show gallstones.
• The scan review identifies structures including the liver, gallbladder, pancreas, spleen, kidneys, intestines, aorta, and vena cava.
• Air in the intestines is usually expected, while changes in the appearance of surrounding abdominal fat can help indicate inflammation.

Clinical Reasoning and Case 1: Acute Cholecystitis

A 42-year-old woman presents with worsening right-upper-quadrant pain, nausea, vomiting, and fever. Her heart rate is elevated, while the other observations described are broadly within normal ranges.

The case demonstrates a stepwise approach to assessment:

• Start with open-ended questions so the patient can describe the problem in their own words.
• For pain, use SOCRATES to guide the history: site, onset, character, radiation, associated symptoms, timing, exacerbating or relieving factors, and severity.
• Consider the full clinical picture, including vital signs, previous episodes, medical history, medications, allergies, and social history.
• Review the imaging for clues. In this case, the gallbladder is distended and contains a gallstone.
• The likely diagnosis is acute cholecystitis, usually caused by a gallstone obstructing the cystic duct. Gallstones may cause pain when the gallbladder contracts, particularly after fatty food, and can lead to inflammation or infection.
• Treatment discussed includes intravenous fluids and antibiotics, followed by cholecystectomy—surgical removal of the gallbladder—once appropriate. The presenter describes this as commonly performed within 48 hours.

Laparoscopic Cholecystectomy Demonstration

An animation shows the main steps of the operation:

1. The patient is placed under general anesthesia and the surgical area is prepared.
2. Small incisions are made, including one near the navel, and ports are inserted.
3. Carbon dioxide is used to inflate the abdomen, creating room to work.
4. A camera and instruments are used to view and operate inside the abdomen.
5. The surgeon identifies the gallbladder, its cystic artery, and cystic duct.
6. The artery and duct are clipped and divided, and the gallbladder is separated from the liver.
7. The gallbladder is placed in a retrieval pouch and removed. The area is checked for bleeding before the ports are closed.

Laparoscopic surgery generally involves small incisions and a quicker recovery than open surgery. After gallbladder removal, the liver still produces bile, which flows directly into the intestine. Patients can generally live normally, though a large amount of fatty food may be harder to digest.

Clinical Reasoning and Case 2: Alcohol-Related Liver Disease

A 57-year-old man is found semiconscious and has repeatedly attended the emergency department. The case introduces liver-function blood tests and the significance of albumin, a protein made by the liver and a marker related to nutritional status.

The patient’s reported heavy vodka consumption and poor nutrition are discussed alongside signs associated with advanced liver disease:

• Jaundice: Yellowing of the eyes or skin.
• Ascites: Fluid accumulating in the abdomen. The presenter links this to reduced production of blood proteins that normally help retain fluid in blood vessels.
• Spider nevi/telangiectasias: Visible small blood vessels.
• Cirrhosis: Permanent scarring that can impair the liver’s ability to process substances and produce proteins and clotting factors.
• Portal hypertension: Increased pressure that can redirect blood into other veins, including those in the esophagus. Enlarged esophageal veins, or varices, can bleed severely if they rupture.

The presenter emphasizes that alcohol misuse can damage multiple organs and affect physical and mental health. The liver can recover from some injury, but established cirrhosis may involve lasting damage and can progress to liver failure.

Gallstone Image Quiz

Students examine CT, ultrasound, and MRI examples and decide whether gallstones are present. The exercise reinforces that gallstones may be visible across different imaging methods and that interpreting scans requires attention to the anatomy and image type.

Additional Discussion and Advice

In the question-and-answer section, the presenter also discusses medical careers and study:

• Managing burnout through hobbies, supportive relationships, reflection, and seeking help or time off when needed.
• The variety of careers and subspecialties in pediatrics, surgery, psychiatry, and neonatology.
• The value of clinical work experience, volunteering, and other relevant activities for aspiring medical students.
• Intercalation as an optional additional year at some UK medical schools, often involving research or another area of study.
• The presenter’s view that medical learning continues throughout a doctor’s career.

A third case involving a jaundiced neonate is mentioned but is not covered in detail during the session.

Speakers and Sources Featured

• Dr. Osama — Presenter and primary speaker.
• Student attendees — Several ask questions during the Q&A. Some are identified by first name, including Inas and Grace; other attendees are not clearly identified.
• Visual and teaching aids — Mentimeter quizzes, a digital anatomy application referred to as “Bob” (also called Live Anatomy or Complete Anatomy in the subtitles), CT, MRI, and ultrasound images, and a laparoscopic cholecystectomy animation.