Anatomy of Liver & Liver Abscess & Portal Hypertension😍

Hepatobiliary System

• ZONES OF LIVER
• Zone 1: Periportal.
• Zone 2: Midzonal.
• Zone 3: Centrilobular.
• Most susceptible to ischemia.

Hepatic Lobule Anatomy

• Liver organized into hexagonal hepatic lobules.
• Central vein at center.
• Portal triads at periphery.
• Hepatocytes are primary cells, between central vein & portal triad.

Portal triad / Liver Pedicle:

 

• Contents: Hepatic vein is not at the portal triad.
• Portal vein (Larger)
• CBD
• Hepatic artery

• Duplex scan: Mickey Mouse sign.

• Largest vein supplying the liver: portal vein.

• Adjacent smaller one: hepatic artery.

• Behind the portal vein: inferior vena cava.

Portal vein

• Portal vein has a monophasic waveform.

• There is no negative flow.

• There is always forward flow above the baseline.

Blood Supply

• Hepatocytes supplied via sinusoids (blood vessels).
• Sinusoid walls contain Kupffer cells → liver macrophages.

CANALS OF HERING

• Connect hepatocytes.

• Contain Oval cells (Stem cells of liver).

Space of Disse

• Space between hepatocytes & sinusoids.

• Site of amyloid deposition in liver.

• Contains Ito cells or stellate cells.

Key Points regarding Ito cells

• Ito cells = hepatic stellate cells, located in space of Disse.

• Store vitamin A in lipid droplets (80% of liver’s retinoids).

• Transform into myofibroblasts in liver injury, causing bridging fibrosis.
• Key role in liver regeneration, fibrosis, and cirrhosis.

• Produce collagen (types I, III) and other matrix proteins.

• Act as antigen-presenting cells and regulate sinusoidal blood flow.

• Identified by gold chloride, cytoglobin, or ASMA staining

Ito Cells vs. Stellate Cells

• Anatomically same, functionally different states.
• Stellate cells: "hyperactive" version
• active in collagen formation
• relevant in cirrhosis.
• Ito cells: "eat, sleep, chill" version
• primarily Vitamin A storage.

Stem Cells

• Liver stem cells for regeneration are oval cells.

• Found in canals of Hering.

Surgical Anatomy of Liver

Condition	Segments Seen	Image Reference
Kidney seen	3, 4b, 5, 6	Image 1
Kidney not seen	2, 4a, 8, 7	Image 2

 

• Three hepatic veins present
• Drain into IVC

• Portal vein division
• Upper half: Segments 2, 4a, 8, 7
• Lower half: Segments 3, 4b, 5, 6

 

Fissures:

• Major (3):
• LHV, MHV, RHV

• Minor (3):
• LPV, RPV, Fissure of Ganz.

• 4 Sectors: (Sections)
• 6 and 7
• 5 and 8
• 4a and 4b
• 2 and 3

• Recent Update:
• Division based on:
• Portal vein > Hepatic vein > Bile duct > Hepatic artery

Cantlie's Line:

• middle line by Middle hepatic vein

• Joins IVC to Gallbladder (MHV location).

• Divides the liver into R and L functional lobes.

Segment Significance:

ㅤ	Right Functional Lobe	Left Functional Lobe	Caudate Lobe
Blood Supply	ㅤ	ㅤ	ㅤ
ㅤ	(R) hepatic artery	(L) hepatic artery	(R) & (L) hepatic artery
ㅤ	(R) portal vein	(L) portal vein	(R) & (L) portal vein
Venous Drainage	ㅤ	ㅤ	ㅤ
ㅤ	(R) hepatic vein	(L) hepatic vein	Directly to IVC
Bile Drainage	ㅤ	ㅤ	ㅤ
ㅤ	(R) hepatic duct	(L) hepatic duct	(R) & (L) hepatic duct
Segments	ㅤ	ㅤ	ㅤ
ㅤ	5: (R) antero inferior	2: (L) lateral superior	1: (Independent lobe)
ㅤ	6: (R) postero inferior	3: (L) lateral inferior	ㅤ
ㅤ	7: (R) postero superior	4a: (L) medial superior	ㅤ
ㅤ	8: (R) antero superior	4b: (L) medial inferior	ㅤ

Ascitic fluid analysis

graph TD
    A[**Ascitic fluid analysis**] --> B{**SAAG**};

    B --> C{**&ge; 1.1g/dL**<br>**due to portal hypertension**}
    B --> D{**&lt; 1.1g/dL**<br>**due to non portal causes**};

    C --> E{**Ascitic protein**<br>**&lt; 2.5g/dL**};
    C --> F{**Ascitic protein**<br>**&ge; 2.5g/dL**};

    E --> G[**Cirrhosis**<br>**Late Budd-Chiari syndrome**<br>**Massive liver metastases**];
    F --> H[**Heart failure/constrictive pericarditis**<br>**Early Budd-Chiari syndrome**<br>**IVC obstruction**<br>**Sinusoidal obstruction syndrome**];
    D --> I[**Biliary leak**<br>**Nephrotic syndrome**<br>**Pancreatitis**<br>**Peritoneal carcinomatosis**<br>**Tuberculosis**];

    %% Styling for background color
    classDef lightblue fill:#e0f2f7;
    class A,B,C,D,E,F,G,H,I lightblue;

• Segment 7:
• Bare area
• Most common (M/c) site for Amoebic liver abscess.

• Segments 4B & 5:
• Gallbladder (GB) fossa,
• removed in radical cholecystectomy for GB Carcinoma (Ca).

• Segment 1:
• Caudate lobe
• Independent Lobe
• Receive bile and arterial blood from both lobes
• Drains directly into IVC
• Hypertrophied in Budd Chiari syndrome

Subacute bacterial Peritonitis (SBP)

• Prophylaxis: Oral Ciprofloxacin / Norfloxacin

Brisbane Classification of Liver Resection:

• Left hepatectomy: Segments 2, 3, 4A & 4B. (Note: 1 NOT INVOLVED)

• Right hepatectomy: Segments 5, 6, 7 & 8.

• Left trisectorectomy (Extended left): Segments 2, 3, 4A, 4B, 5 & 8.

• Right trisectorectomy (Extended right): Segments 5, 6, 7, 8, 4A & 4B.

• Mnemonic: Bris Bane → Bare area of liver → Liver → Liver resection

Cystic Lesions of the Liver

Simple Cyst: (Image 1)

• Cystic lesions contain water

• They appear gray on CT.

• The cyst has a thin wall.

Liver Abscess: (Image 2)

• An abscess has a thick wall.
• This is due to inflammation and granulation tissues.

• History of dysentery followed by abscess:
• Amoebic liver abscess

Central dot sign: (Image 3)

• A lesion in the liver with a central dot.

• Seen in Caroli's disease,
• Type 5 choledochal cyst

Liver Abscess

• Breaks tissue.
• Ulcer + hemorrhage
• Mucus in stools

• Forms flask-shaped ulcers.
• Trophozoites seen inside.

• Red dots (RBCs) indicate erythrophagocytosis.

• In liver, causes anchovy sauce appearance (pus).

• M/c manifestation: Asymptomatic cyst passage

Intestinal Amoebiasis

• Diagnosis
• Stool samples: 3 consecutive days

• Axenic culture medium:
• Pure culture medium.
• No added supplements.
• Example: Diamond medium.
• Diamonds are pure

• Polyxenic medium:
• Requires added supplements for bacterial growth.
• Craige's culture, Nelson medium, Balamuth medium, Boeck and Dr Bohlav medium.

DOC

---

Drug	Type of Amoebiasis
Diloxanide Furoate (or Paromomycin)	For Asymptomatic Intestinal amebiasis ↳ Luminal amoebiasis (Carrier state) ↳ Dil oxanide furoate → heart lumen → luminal amebiasis
Nitroimidazole (Nidazole)	For Symptomatic ↳ Intestinal and Hepatic amoebiasis ↳ (tissue amebicide) e.g. • Metronidazole, Tinidazole, Secnidazole, • Ornidazole, Satranidazole

• Nidazoles can cause disulfiram like reaction, so are C/I in alcoholics.

---

Morphology and Diagnosis

Feature	Entamoeba histolytica	Entamoeba coli
Trophozoite	ㅤ	ㅤ
Erythrophagocytosis	Present (RBCs engulfed)	Absent (No RBCs)
Karyosome	One Nucleus → Central	Eccentric
Cyst	ㅤ	ㅤ
Nuclei	1-4	1-8
Nucleus Type	Cartwheel nucleus	No cartwheel nucleus
Chromatoid Body Composed of (Iron hematoxylin stain)	Ribonucleoprotein	RNP

• Iron Hematoxylin Stain: Used for chromatoid body.

Liver Abscess

Types: Amoebic vs Pyogenic:

Feature	Amoebic	Pyogenic
Organism	Entamoeba histolytica	M/c E. Coli; Asia: Klebsiella; CGD: S. aureus
Route of Infection	Bowel → Portal vein (laminar flow to right)	Ascending cholangitis (via biliary tree)
M/c Segment	Segment 7 (Bare area) Right lobe	N/A (More widespread involvement common) Right lobe
Number	Solitary	50% Solitary, 50% Multiple
Clinical Features	Right hypochondriac pain + fever History of dysentery	Right hypochondriac pain + fever (more toxic/sick)
Labs	↑↑ PT/INR "Anchovy-sauce pus" aspirate ↳ trophozoites in pus	↑↑ ALP
IOC	CECT (shows pus collection)	CECT (shows pus collection)
Management (Mx)	Metronidazole (800 mg) TDS for 10 days. F/b Paromomycin If responding, continue for 2-3 weeks	Broad spectrum IV Antibiotics + Early drainage  (pigtail catheter)
ㅤ	If not responding: Drainage (pigtail catheter) Drainage indications: • 2° infections • >5 cm • Left lobe • pregnancy • impending rupture	ㅤ

Life Cycle of Entamoeba histolytica

• Host: Humans.

• Infective stage: Mature quadrinucleate cyst.

• Transmission: Ingestion (faeco-oral route).

Ulcer Type	Shape	Pathogen
TB ulcer	• Transverse (horizontal)	Mycobacterium tuberculosis
Typhoid ulcer	• Longitudinal • Like a tie is worn longitudinally	Salmonella typhi
Amoebic ulcer	• Flask shaped  • (classic, undermine mucosa)	Entamoeba histolytica

Budd Chiari

• Hepatic venous outflow obstruction

• At level of hepatic veins ± IVC

• Leads to hepatic congestion → portal hypertension

• Investigation of choice
• Colour flow Doppler – initial investigation

• Treatment
• Initial: Systemic anticoagulation
• Surgical intervention
• If refractory to medical therapy
• Percutaneous angioplasty
• TIPS + thrombolytic therapy
• Restores hepatic venous outflow
• Surgical shunting
• Side-to-side portacaval shunt
• Portal vein becomes hepatic outflow tract

• Poor prognostic factors
• Involvement of all three hepatic veins and/or portal vein
• Ascites
• Older age at presentation
• High Child–Pugh score
• Chronic disease at presentation

Kasabach–Merritt Syndrome

• Seen in infants

• Life-threatening

Pathophysiology

• Platelet trapping in tumor →

• Severe thrombocytopenia

• Consumptive coagulopathy

• DIC-like state

• Kaposiform hemangioendothelioma

• Tufted angioma

• Not infantile hemangioma

• ↓ Platelets

• ↓ Fibrinogen

• ↑ PT / aPTT

• ↑ D-dimer

Hydatid Cyst

• Features:
• Organism: Echinococcus granulosus.
• Hosts:
• Definitive: Dog.
• Intermediate: Sheep.
• Accidental intermediate: Man.

• Clinical Features: Right hypochondrium pain.

• IOC: CECT.

• Whose (WHO CE) Dog Ghar mem → Gharbi

• Water lily sign:
• Lesion with air fluid level,
• i.e. Spherical cyst and membranes floating in the fluid level.

• Other Signs:
• Rising sun sign.
• Serpent sign.
• Cumbo sign.
• Meniscus sign.

Layers of hydatid cyst

Layers of hydatid cyst	Notes
Pericyst	• Only Host derived cyst • made of infective cells
Ectocyst	• Paintbrush
Endocyst	• Germinal layer • New organisms/growths are called brood capsules. • They contain hooklets (ZN stain positive)

• Echi → Casino (casoni) ilu chuuthu kalich → 5 alkk (5 Arc) paisa kodukkkanam → Olichirun (Hide - hydatid cyst) → in water lillyy → Dog ne bite cheyyich → first liver then lungs

Classification (WHO-IWGE 2001 / Gharbi 1981 USG based):

WHO-IWGE 2001	Gharbi 1981 (USG based)	Characteristics	ㅤ
CE 1	Type I	• Unilocular anechoic, double-line sign	1
CE 2	Type III	• Multiseptate, rosette-like, honeycomb cyst	2 or more
CE 3a	Type II	• Cyst with floating, detached membranes • Water-lily sign	3A → 2 A flower
CE 3b	Type III	• Mother Cyst with daughter cysts in solid matrix	Baby
CE 4	Type IV	• Heterogeneous hypo/hyperechoic contents • No daughter cysts → Hydatid sand	ㅤ
CE 5	Type V	• Solid, calcified wall (Dead cyst)	ㅤ

Mnemonic:

• Echinococcus granulosus → Granny kk ekkili eduthu (Echinococcus gran) → CBSE 3rd std Appu (3a) → 2 (Type2) Lilly (water Lilly) kondu koduthu

Treatment of Echinococcus granulosus

• First line: Albendazole

• PAIR Process:
• P - Puncture of cyst.
• A - Aspirate.
• I - Injection scolicidal agent
• R - Re-aspiration.

• Scolicidal agents:
• Hypertonic saline (M/c),
• Cetrimide,
• Mebendazole
• Alcohol.
• Note: Formalin not used (causes chemical cholangitis).

• Contraindications (C/I) for PAIR:
• 4 and 5
• Cystobiliary communication
• During aspiration, if bilirubin level positive
• DO NOT INJECT SCOLICIDAL AGENT
• Dead cyst, Calcified cyst, Extrahepatic cyst.
• Deep seated, Multiloculated.

• Surgery: 
• Done if PAIR is C/I
• Liver resection or cystopericystectomy

Echinococcus multilocularis:

• Multilocular AKA alveolar hydatid cyst.

• M/C site: Liver.

• Second M/C site: Lungs.

Portal Hypertension

• Variceal cause of upper GI bleeding.

• Doppler (Diagnosis): Hepatic venous Pressure Gradient (HVPG).

HVPG Measurement

Porto-systemic shunts

1. Left gastric + short gastric veins → Distal esophageal veins.

2. Left gastric/gastroepiploic vein → Esophageal/paraesophageal veins.

3. Caput medusae: Periumbilical.

4. Rectum

5. Bare area of liver (Segment 7).

Clinical Features (C/F)

• Upper GI bleeding.

• Ascites.

• Splenomegaly.

• Signs of liver failure.

• Patient with hemetemesis and splenomegaly is assumed to have variceal bleed unless proven otherwise

Management

ABC Management

• Airway Mx: Prevent aspiration.

• IV Pantoprazole: Given after endoscopy.

IV Drugs

• Best: IV terlipressin.
• Not used as it may precipitate MI

• m/c used: IV octreotide.

• Not used: IV propranolol (if unstable).

Upper GI Endoscopy

• (Patient stabilised).

• Banding (m/c) > Sclerotherapy (Sodium tetradecyl sulphate).

• Assess bleeding:
• Controlled: 24hr observation → Normal → Discharge on oral propranolol.
• Uncontrolled: 2nd attempt at UGI-scopy → Fail → Sengstaken Blakemore tube.

Temporary Control of Bleeding (until patient is ready for TIPSS)

• Linton tube:
• 3 channels, 1 balloon.

• Sengstaken Blakemore tube:
• 3 channels, 2 balloons.
• Gastric is inflated first → if bleeding not controlled → oesophageal is inflated

• Minnesota tube:
• 4 channels, 2 balloons
• Many → Minnesota

• Sengstaken → Sung → My (Minnesota) Song’s (Sengs) Lines (Linton)

• Mainly 3 channels, except mine → Me need 4 channels

• Mainly 2 balloons, except lintOne → One balloon, Others 2

Transjugular Intra-hepatic Portosystemic Shunt (TIPSS)

• Shunt b/w portal vein & hepatic vein.

• Portal vein is formed by SMV and splenic vein

• Non-selective (Splenic & bowel blood are both shunted).

Complications:

• Rupture of capsule: Earliest.

• Blocked → Rebleeding: m/c.

• MC late complication: Stent thrombosis

• Encephalopathy:
• D/t nonselective shunt.
• Bcz bacteria from bowel enters circulation

Other Shunts

Scoring Systems

1. Rockall's score: Prognostic scores.

2. BLEED criteria: Prognostic scores.

3. Child Pugh Turcotte score.

Forrest's Classification Table

• For peptic ulcer bleeding, endoscopic assessment.

• 3 days trip to forest →
• 1st day → injury and bleed
• 2nd day → clot
• 3rd day → clean ulcer