Distinguishing Hepatorenal Syndrome Type 1 vs Type 2
The key distinction between HRS-1 (now called HRS-AKI) and HRS-2 is that HRS-1 is characterized by rapid deterioration of renal function often due to a precipitating event, while HRS-2 features stable, less severe kidney dysfunction that progresses slowly without an obvious precipitant. 1
Updated Terminology and Classification
The traditional classification of HRS has evolved in recent years:
- HRS Type 1 is now termed HRS-AKI (Hepatorenal Syndrome-Acute Kidney Injury) 2, 1
- HRS Type 2 remains as a distinct entity characterized by more stable renal dysfunction
Diagnostic Criteria for HRS-AKI (formerly HRS Type 1)
HRS-AKI is defined by:
- Cirrhosis with ascites
- AKI according to ICA-AKI criteria (increase in serum creatinine ≥0.3 mg/dL within 48 hours or ≥50% from baseline within 7 days) 2
- No response after 2 days of diuretic withdrawal and albumin infusion (1 g/kg/day)
- Absence of shock
- No current or recent nephrotoxic drugs (NSAIDs, aminoglycosides, contrast media)
- No signs of structural kidney injury (proteinuria >500 mg/day, microhematuria, abnormal renal ultrasound) 2
AKI Staging in HRS
| AKI Stage | Description |
|---|---|
| Stage 1 | Increase of creatinine ≥0.3 mg/dL up to 2-fold of baseline |
| Stage 2 | Increase in creatinine between 2-fold and 3-fold of baseline |
| Stage 3 | Increase in creatinine >3-fold of baseline or creatinine >4 mg/dL with acute increase ≥0.3 mg/dL or initiation of RRT [2,3] |
Characteristics of HRS Type 2
HRS Type 2 is characterized by:
- Moderate and stable or slowly progressive renal dysfunction
- Often occurs without an obvious precipitating event
- Clinically manifests primarily as refractory ascites 1
- More chronic course with longer survival compared to HRS-AKI 4
- Serum creatinine typically elevated but stable
Key Differentiating Features
| Feature | HRS-AKI (Type 1) | HRS Type 2 |
|---|---|---|
| Onset | Acute, rapid deterioration | Gradual, slowly progressive |
| Precipitating factors | Often present (infections, especially SBP, GI bleeding) | Often absent |
| Clinical presentation | Acute renal failure | Primarily refractory ascites |
| Prognosis | Very poor without treatment (days to weeks) | Better than HRS-AKI (months) [4] |
| Treatment response | ~40-50% respond to vasoconstrictors + albumin [4] | Recurrence common after treatment withdrawal [3] |
Treatment Approach Differences
HRS-AKI (Type 1)
- Requires urgent intervention
- First-line: Terlipressin plus albumin (1 g/kg on day 1, followed by 40 g/day) 2, 3
- Alternative: Norepinephrine plus albumin (in ICU setting) 2, 3
- Treatment until serum creatinine decreases below 1.5 mg/dL or maximum 14 days 2, 3
- Consider expedited liver transplant evaluation 3
HRS Type 2
- Less urgent intervention needed
- TIPS may be more applicable for HRS-2 than for HRS-AKI 2
- Vasoconstrictors plus albumin not routinely recommended due to high recurrence after withdrawal 2
- Focus on management of refractory ascites
- Liver transplantation remains definitive treatment 2, 3
Clinical Pearls
- Baseline serum creatinine is the most consistent predictor of response to treatment and survival in HRS-AKI 5
- Patients with serum creatinine <5.0 mg/dL are more likely to benefit from terlipressin 5
- A sustained rise in mean arterial pressure is required for HRS reversal 5
- Systemic inflammation plays a critical role in HRS pathophysiology, and HRS is not purely "functional" as previously thought 1, 6
- Bacterial infections, particularly SBP, are the most important risk factors for HRS-AKI 3
Remember that early diagnosis and prompt treatment are critical for improving outcomes in HRS-AKI, while HRS-2 management focuses more on controlling ascites and preparing for liver transplantation.