Everything You Need to Know About Cirrhosis and portal hypertension for Step 1

Cirrhosis and portal hypertension show up everywhere on Step 1: in vague stem clues (spider angiomas, caput medusae), labs (AST:ALT ratios), and complications you’re expected to recognize instantly (variceal bleeds, hepatorenal syndrome, hepatic encephalopathy). If you can connect the fibrosis → resistance → portal pressure → collaterals + fluid shifts story, a lot of GI and pharm suddenly feels simpler.

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Big-picture definitions (Step 1 framing)

Cirrhosis

Cirrhosis = diffuse hepatic fibrosis + regenerative nodules causing:

• Distorted liver architecture
• Increased intrahepatic vascular resistance
• Progressive liver dysfunction (synthetic, metabolic, detox)

First Aid cross-ref: GI—Liver pathology (Cirrhosis), Portal HTN, Ascites, Hepatic encephalopathy, Varices

Portal hypertension

Portal hypertension = elevated portal venous pressure, classically from increased resistance to portal flow (most commonly cirrhosis in the U.S.).

A common threshold concept: clinically significant portal HTN often discussed around hepatic venous pressure gradient (HVPG) ≥10–12 mmHg, where varices/bleeding risk rises.

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Pathophysiology: the “why” behind every complication

1) How cirrhosis forms

Chronic injury (viral hepatitis, alcohol, NASH, autoimmune, cholestatic disease, etc.) → inflammation → activation of hepatic stellate cells (Ito cells) in the space of Disse → collagen deposition + extracellular matrix remodeling → bridging fibrosis + nodules.

High-yield detail: Stellate cells are key fibrogenic drivers (test loves “Ito cells make collagen”).

2) Why portal pressure rises

Portal pressure increases primarily because of:

• Structural resistance: fibrotic scarring + nodule formation compress sinusoids/venules
• Dynamic resistance: increased vasoconstrictor tone inside the liver
• Splanchnic vasodilation (NO-mediated) increases portal inflow, worsening the gradient

You can think of it like:

• “Tight liver” (hard to push blood through) + “wide splanchnic pipes” (more flow coming in)

3) Why ascites happens (multiple hits)

Ascites in cirrhosis is not “just low albumin,” though that contributes.

Key drivers:

• Portal HTN → ↑ hydrostatic pressure in splanchnic capillaries → fluid transudation
• Splanchnic vasodilation → ↓ effective arterial blood volume → RAAS/SNS/ADH activation
  • Aldosterone → Na⁺ retention
  • ADH → water retention
• Hypoalbuminemia → ↓ oncotic pressure (adds on)

Step 1 tie-in: This is why cirrhotic patients can be total-body fluid overloaded yet intravascularly “underfilled.”

4) Portosystemic shunts and collateral formation

When portal flow is blocked, blood diverts through collateral vessels → hallmark findings:

First Aid cross-ref: Anastomoses (portal-caval), Varices

5) Hyperammonemia → hepatic encephalopathy

Ammonia ($NH_3$) normally detoxified by liver (urea cycle). In cirrhosis/portosystemic shunting:

• Less hepatic clearance + shunting → ↑ ammonia
• Ammonia crosses BBB → astrocyte swelling (via glutamine) → altered mental status

Classic exam clue: asterixis (flapping tremor), confusion, sleep-wake reversal.

Precipitants to memorize (very testable):

• GI bleed (protein load in gut)
• Infection (esp SBP)
• Constipation
• Hypokalemic metabolic alkalosis (shifts $NH_4^+ \to NH_3$)
• Sedatives/opioids

6) Hepatorenal syndrome (HRS): functional renal failure

Severe cirrhosis → intense splanchnic vasodilation → renal vasoconstriction + low renal perfusion → pre-renal picture but kidneys are structurally normal.

Hallmarks:

• Very low urine Na⁺, bland sediment
• Rising creatinine, oliguria
• Often triggered by SBP, large-volume paracentesis without albumin, overdiuresis

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Etiologies: recognize them from stems

Common causes of cirrhosis (USMLE favorites)

• Alcohol-associated liver disease
• Chronic viral hepatitis (HBV, HCV)
• NASH (metabolic syndrome)
• Autoimmune hepatitis
• Primary biliary cholangitis (PBC): antimitochondrial Ab, pruritus, cholestatic pattern
• Primary sclerosing cholangitis (PSC): p-ANCA, beading on ERCP/MRCP, associated with UC, ↑ cholangiocarcinoma risk
• Hereditary hemochromatosis: “bronze diabetes,” cardiomyopathy, arthropathy
• Wilson disease: neuro/psych + liver + Kayser–Fleischer rings, low ceruloplasmin
• $\alpha_1$-antitrypsin deficiency: liver disease + panacinar emphysema

First Aid cross-ref: Hemochromatosis, Wilson, A1AT deficiency, PBC/PSC

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Clinical presentation: what to spot in 10 seconds

Symptoms

• Fatigue, anorexia, weight loss
• RUQ discomfort
• Pruritus (more cholestatic etiologies)
• Confusion (encephalopathy)

Signs of chronic liver disease (high-yield)

• Jaundice
• Spider angiomas (classically above nipples)
• Palmar erythema
• Gynecomastia, testicular atrophy (↑ estrogen due to impaired metabolism)
• Ascites
• Splenomegaly (portal HTN → congestive splenomegaly → thrombocytopenia)
• Caput medusae
• Asterixis (encephalopathy)

Complications you must associate with portal HTN

• Variceal hemorrhage (life-threatening UGIB)
• Ascites
• Spontaneous bacterial peritonitis (SBP)
• Hepatic encephalopathy
• Hepatorenal syndrome
• Hepatocellular carcinoma (HCC) (esp HBV/HCV, cirrhosis)

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Diagnosis: labs + imaging + high-yield scoring concepts

Core labs (pattern recognition)

Synthetic dysfunction (big deal for severity):

• ↑ PT/INR (short half-life clotting factors)
• ↓ albumin

Hepatocellular injury:

• ↑ AST/ALT
  • Alcohol: often AST:ALT ≥ 2:1 (plus ↑ GGT)
  • Viral: often higher ALT than AST (variable)

Cholestatic pattern:

• ↑ ALP ± ↑ GGT, ↑ bilirubin

Portal HTN clue:

• Thrombocytopenia (splenic sequestration)

Imaging

• Ultrasound: nodular liver, ascites, splenomegaly; Doppler for portal vein flow
• Elastography: noninvasive fibrosis assessment (Step 1 may mention conceptually)
• Endoscopy: screening/diagnosis of esophageal varices

Paracentesis (ascites workup = very Step-relevant)

Do diagnostic paracentesis for new ascites or hospitalized cirrhotic with ascites.

SAAG (serum-ascites albumin gradient): $SAAG = Albumin_{serum} - Albumin_{ascites}$

• SAAG ≥ 1.1 g/dL → portal hypertension likely (transudative physiology)
• SAAG < 1.1 g/dL → non-portal causes (malignancy, pancreatitis, TB, nephrotic syndrome)

SBP diagnostic criterion:

• Ascitic fluid PMNs ≥ 250/µL (neutrophils), often with fever/abdominal pain/worsening encephalopathy

First Aid cross-ref: Ascites—SAAG, SBP

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Treatment: what to do for each complication (Step 1 + Step 2 overlap)

Cirrhosis: general principles

• Treat underlying cause (HCV antivirals, HBV suppression, alcohol cessation, weight loss for NASH, immunosuppression for autoimmune hepatitis)
• Vaccinate (HAV, HBV if nonimmune)
• Avoid hepatotoxins (alcohol, unnecessary acetaminophen excess)
• Nutrition: adequate protein unless severe encephalopathy (Step often tests “don’t protein-starve routinely”)

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Portal hypertension complications: rapid-response algorithms

1) Esophageal varices (prophylaxis and acute bleed)

Primary prophylaxis (known varices or high-risk features):

• Nonselective beta-blocker: propranolol, nadolol, carvedilol
  Mechanism: $\beta_1$ ↓ CO and $\beta_2$ blockade → unopposed $\alpha$ → splanchnic vasoconstriction → ↓ portal inflow

Acute variceal bleed (classic Step sequence):

1. Stabilize: ABCs, IV access, transfuse as needed
2. Octreotide (somatostatin analog) → splanchnic vasoconstriction
3. Endoscopic band ligation
4. Antibiotic prophylaxis (e.g., ceftriaxone) because GI bleed in cirrhotics → high infection/SBP risk
5. Refractory: TIPS (transjugular intrahepatic portosystemic shunt)

TIPS high-yield complication: worsens hepatic encephalopathy (more shunting of toxins).

First Aid cross-ref: Varices—octreotide, banding, TIPS; Beta blockers

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2) Ascites

• Sodium restriction
• Diuretics: spironolactone (first-line) ± furosemide
  • Rationale: cirrhotics have secondary hyperaldosteronism → spironolactone hits the driver
• Large-volume paracentesis for tense/refractory ascites
  • Give IV albumin when large volume removed (prevents circulatory dysfunction/HRS)
• Refractory cases: consider TIPS or transplant evaluation

Classic mistake to avoid on exams: loop diuretic alone without aldosterone antagonism is often less effective.

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3) Spontaneous bacterial peritonitis (SBP)

• Diagnose with PMNs ≥ 250/µL
• Treat empirically: 3rd-gen cephalosporin (ceftriaxone or cefotaxime)
• Give albumin in select patients to reduce renal failure risk
• Secondary prophylaxis after SBP episode: e.g., norfloxacin/ciprofloxacin or TMP-SMX (institution-dependent)

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4) Hepatic encephalopathy

• Lactulose (first-line): acidifies colon → traps ammonia as $NH_4^+$ + cathartic effect
• Rifaximin: decreases ammonia-producing gut bacteria (often added)
• Correct precipitating factors (GI bleed, infection, constipation, electrolyte issues)

First Aid cross-ref: Encephalopathy—lactulose, rifaximin

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5) Hepatorenal syndrome (HRS)

• Stop nephrotoxins/diuretics, treat triggers (SBP)
• Albumin + vasoconstrictor therapy (e.g., terlipressin where available; in U.S., norepinephrine in ICU or midodrine + octreotide used)
• Definitive: liver transplant

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High-yield associations & “exam one-liners”

Classic physical findings and what they mean

• Spider angiomas + palmar erythema → hyperestrogenemia from impaired hepatic metabolism
• Gynecomastia → ↑ estrogen, also alcohol association
• Asterixis → hepatic encephalopathy (also seen in CO$_2$ retention/uremia)

Laboratory pearls

• PT/INR rises early in liver failure (factor VII short half-life)
• Platelets low early due to splenic sequestration (portal HTN)
• AST:ALT ≥ 2 → alcoholic liver injury pattern (not absolute but very testable)

HCC screening concept (commonly tested)

• Cirrhosis increases HCC risk (esp HBV/HCV)
• Screening: ultrasound ± AFP every 6 months (Step 1 may just want “cirrhosis predisposes to HCC”)

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Quick table: complications → best next step (high-yield)

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First Aid-style wrap-up (what to memorize)

• Cirrhosis = fibrosis + nodules → portal HTN + liver failure.
• Portal HTN → varices, ascites, splenomegaly.
• Varices: nonselective beta blockers prophylaxis; acute bleed: octreotide + banding + antibiotics, consider TIPS.
• Ascites: spironolactone first-line; SAAG ≥ 1.1 suggests portal HTN.
• Encephalopathy: lactulose (traps $NH_3$ as $NH_4^+$) ± rifaximin; look for precipitating triggers.
• SBP: PMN ≥ 250, treat with 3rd-gen cephalosporin.
• Stellate (Ito) cells drive fibrosis; cirrhosis predisposes to HCC.