Diagnosing hepatorenal syndrome
Doctors anticipate many complications of chronic liver disease including cancer, liver failure, spontaneous bacterial peritonitis, and hepatorenal syndrome. Therefore, once symptoms develop suggesting any of them, they are considered to be most likely.
In the case of hepatorenal syndrome, your doctor will listen carefully to your symptoms and then ask for some tests to confirm the diagnosis. The challenging part of diagnosing hepatorenal syndrome is the exclusion of other kidney problems that may cause the patient’s condition. This includes kidney injury in response to medications, infections, stones, and others. The most commonly ordered tests in those cases are:
- Kidney function tests: Contrary to popular belief, there are more tests for renal functions than creatinine and urea levels. Parameters like eGFR and cystatin levels are equally as important and indicate even minor variations of renal functions. You should know that in order for creatinine or urea levels to rise significantly, more than 75% of the kidney’s filtration capacity should be lost. They are, therefore, not sensitive enough to detect mild variations of kidney function.
- Liver function tests: Liver function tests do not correlate to the severity of the condition nor help confirm the diagnosis. However, they are needed to assess the general condition of the patient.
- Serum electrolytes: The levels of some electrolytes can assess the condition of the kidney and the response to treatment.
- Complete blood count: A complete blood count is essential in such cases to assess the presence of infection. An elevated white blood count is the main indicator, mainly if elevated.
- Blood cultures and ascitic fluid culture: Detecting the site of infection can be challenging. One of the commonest triggers is spontaneous bacterial peritonitis, which can be detected by taking cultures from the ascitic fluid and measuring the amount of white blood cells in them.
- Urine analysis: Urine analysis is perhaps the most important investigation of the above. Detecting the amount of proteins in urine, evidence of infection and the albumin-to-creatinine ratio in urine is of utmost importance. In hepatorenal syndrome, the level of protein in urine is minimal, otherwise it means that there is another disease affecting the kidney. One of the important parameters that should be assessed is something called fractional excretion of sodium, which can differentiate between a problem related to the kidney itself and hepatorenal syndrome.
Other than lab tests, there are imaging studies that can help exclude other condition, but they are much less specific than lab tests. Abdominal ultrasound can assess the state of the liver and kidney. Liver cirrhosis can be seen by ultrasound, and the kidney can show structural changes in abdominal ultrasound, which is against a diagnosis of hepatorenal syndrome.
