Elastography Values During Viral URTI with Elevated Transaminases
Yes, liver elastography measurements increase during acute viral infections with elevated transaminases, and these elevated values do not accurately reflect true liver fibrosis during the acute inflammatory phase.
Key Evidence
The most direct evidence comes from a landmark study demonstrating that acute viral hepatitis significantly increases liver stiffness values measured by transient elastography 1. In this study of 18 patients with acute viral hepatitis:
- All patients showed liver stiffness values exceeding cutoffs for significant fibrosis or cirrhosis during peak transaminase elevation
- Liver stiffness progressively decreased in parallel with transaminase normalization (P < 0.0001)
- A significant positive correlation existed between transaminases and liver stiffness measurements (r = 0.53 for ALT, r = 0.51 for AST)
- The study explicitly concluded that liver stiffness measurement is not reliable for detecting advanced fibrosis or cirrhosis in patients with acute hepatitis 1
Mechanism and Clinical Implications
Why This Occurs
Liver stiffness measurements reflect not only fibrosis but also necroinflammatory activity. During acute viral infections:
- Hepatocellular inflammation and necrosis increase tissue stiffness independent of fibrosis 1, 2
- The effect is proportional to the degree of transaminase elevation 2
- Liver stiffness can increase 1.3- to 3-fold during ALT flares 2
Specific to Respiratory Viral Infections
Recent evidence from COVID-19 studies confirms this phenomenon extends to respiratory viral infections:
- Post-COVID-19 patients showed significantly higher liver stiffness (5.26 ± 1.63 kPa) compared to controls (4.30 ± 0.96 kPa) within 6 months of infection 3
- Nearly 48% of COVID-19 patients had persistent abnormal liver biochemistry up to 6 months post-infection 4
- Influenza specifically causes severe hepatic involvement, including marked transaminase elevations 5
Critical Clinical Pitfalls
Do Not Misinterpret as Cirrhosis
The major pitfall is misclassifying patients with acute inflammation as having advanced fibrosis or cirrhosis based on elastography alone 1, 6. The AGA guidelines emphasize that:
- Standard cirrhosis cutoffs (12.5 kPa for HCV) 7 were validated in chronic liver disease, not acute inflammation
- Even the higher cutoff of 17.0 kPa for portal hypertension screening 8 can be exceeded during acute hepatitis without true cirrhosis 1
When to Perform Elastography
Avoid elastography during acute illness with elevated transaminases. Instead:
- Wait until transaminases normalize or are ≤2× upper limit of normal 1
- In children and young adults with inflammatory liver disease, high ALT values are associated with falsely elevated liver stiffness measurements in those with minimal fibrosis 6
- The relationship between ALT and liver stiffness is strongest in patients with no/minimal fibrosis (F0-F2), while advanced fibrosis (F3-F4) shows less influence from inflammation 6
Practical Algorithm
For patients with viral URTI and elevated transaminases:
- Do not perform elastography during acute illness - values will be falsely elevated
- Repeat transaminases until normalization or ≤2× ULN
- Perform elastography only after biochemical improvement - typically requires waiting until inflammatory markers resolve
- If elastography was already performed during acute phase - disregard the elevated values and repeat after resolution 1
Strength of Evidence
The evidence is consistent across multiple studies spanning different viral infections (acute viral hepatitis 1, COVID-19 3, 4, influenza 5) and patient populations (adults 1, 2 and children 6). The AGA guidelines 8, 7, while not specifically addressing acute viral URTI, emphasize that elastography cutoffs were validated in chronic liver disease and that necroinflammatory activity must be carefully considered when interpreting results 7.