What is the best course of action for a patient with abdominal pain, diarrhea, nodular liver contour on ultrasound, normal platelets and liver function tests (LFTs), impaired renal function (eGFR), increased urine microalbumin, and tachycardia?

Diagnostic Workup for Nodular Liver with Systemic Manifestations

This patient requires urgent CT abdomen/pelvis with IV contrast to evaluate for cirrhosis complications, followed by immediate hepatology referral and workup for systemic amyloidosis given the constellation of nodular liver, renal dysfunction with proteinuria, and tachycardia. 1

Immediate Imaging and Laboratory Evaluation

The nodular liver contour on ultrasound strongly suggests cirrhosis or infiltrative disease, and despite normal platelets and LFTs, advanced liver disease cannot be excluded. 1

• CT abdomen/pelvis with IV contrast is the next diagnostic step to characterize liver architecture, assess for portal hypertension, evaluate spleen size, and identify ascites or varices 1
• Normal LFTs do not exclude advanced fibrosis or cirrhosis—up to 20% of patients with significant liver disease have normal biochemical tests 1
• The combination of nodular liver with renal impairment (low eGFR) and microalbuminuria raises concern for systemic disease affecting multiple organs 1

Critical Differential Diagnosis Considerations

The triad of nodular liver, renal dysfunction with proteinuria, and tachycardia should prompt evaluation for cardiac amyloidosis or other infiltrative diseases. 1

• Cardiac amyloidosis commonly presents with restrictive cardiomyopathy causing tachycardia, hepatic congestion leading to nodular appearance, and renal involvement with proteinuria 1
• Polycystic liver disease (PLD) can present with nodular contour and is associated with ADPKD, which would explain the renal dysfunction and microalbuminuria 1
• Cirrhosis from any cause (alcohol-related, NAFLD, viral hepatitis) can present with nodular liver and secondary renal dysfunction (hepatorenal syndrome) 1

Essential Additional Workup

Order the following tests immediately to narrow the differential:

• Echocardiogram to evaluate for restrictive cardiomyopathy, valvular disease, or pericardial effusion that could explain tachycardia and suggest infiltrative disease 1
• Serum and urine protein electrophoresis with immunofixation to screen for monoclonal gammopathy if amyloidosis is suspected 1
• NT-proBNP or BNP to assess for heart failure, which could explain tachycardia and contribute to hepatic congestion 1
• Complete hepatitis panel (HBV, HCV), autoimmune markers (ANA, ASMA, AMA), iron studies, alpha-1 antitrypsin, and ceruloplasmin to identify treatable causes of liver disease 1
• Albumin, INR, and bilirubin to assess synthetic liver function, as these may be abnormal even when transaminases are normal 1

Liver Biopsy Considerations

If imaging and initial workup do not establish a diagnosis, liver biopsy should be strongly considered to differentiate between cirrhosis, infiltrative disease (amyloidosis, sarcoidosis), and polycystic liver disease. 1

• Transjugular approach is preferred if platelets drop or coagulopathy develops, though current platelet count is normal 1
• Biopsy is particularly indicated when competing diagnoses exist or when systemic disease like amyloidosis is suspected 1

Management of Concurrent Symptoms

The abdominal pain and diarrhea require evaluation for complications of liver disease:

• Screen for spontaneous bacterial peritonitis if ascites is present on imaging, even without fever 1
• Evaluate for portal hypertensive gastropathy or varices as potential sources of GI symptoms 1
• Consider small intestinal bacterial overgrowth (SIBO), which is common in cirrhosis and causes diarrhea 1

Renal-Hepatic Syndrome Evaluation

The combination of liver disease and renal dysfunction requires assessment for hepatorenal syndrome versus primary renal disease:

• Urine sodium, urine osmolality, and fractional excretion of sodium help differentiate hepatorenal syndrome from other causes of acute kidney injury 1
• Renal ultrasound to evaluate kidney size and echogenicity—small kidneys suggest chronic disease, while enlarged kidneys with cysts confirm ADPKD 1
• 24-hour urine protein quantification to characterize the degree of proteinuria and guide renal workup 1

Urgent Referrals

Hepatology consultation is mandatory for patients with suspected cirrhosis or infiltrative liver disease to coordinate diagnostic workup and initiate surveillance for hepatocellular carcinoma and varices 1

Nephrology consultation should be obtained given the combination of reduced eGFR and microalbuminuria to determine if this represents primary renal disease or secondary involvement 1

Cardiology evaluation is warranted if echocardiogram shows abnormalities or if tachycardia persists without clear explanation, particularly to rule out infiltrative cardiomyopathy 1

Common Pitfalls to Avoid

• Do not assume normal LFTs exclude significant liver disease—synthetic function tests (albumin, INR) and imaging are more reliable for detecting cirrhosis 1
• Do not attribute all findings to a single diagnosis without excluding systemic disease—the multi-organ involvement (liver, kidney, cardiac) suggests a systemic process like amyloidosis 1
• Do not delay imaging while pursuing extensive laboratory workup—CT with contrast provides critical anatomic information that guides all subsequent decisions 1
• Do not overlook polycystic liver disease in patients with renal dysfunction—ADPKD affects 80% of patients over age 30 and requires specific management 1