A 70-year-old man with a history of chronic Hepatitis B presents with shortness of breath and edema. Lab tests show low serum albumin and high serum creatinine. Urinalysis shows high urinary protein. What is the likely diagnosis and next steps?
This patient's presentation suggests nephrotic syndrome, potentially secondary to membranous nephropathy, which can be associated with chronic Hepatitis B. The next step should include a kidney biopsy to confirm the diagnosis. If confirmed, he may require antiviral therapy for Hepatitis B, as well as immunosuppressive therapy for the nephrotic syndrome.