Gil-López, F. Santoyo

Renal dysfunction is highly prevalent among patients with cirrhosis and has major implications for management, prognostication, and liver transplant decision-making. Both acute kidney injury (AKI) and chronic kidney disease (CKD) occur frequently in this population and are driven by a complex interplay of hemodynamic derangements, systemic inflammation, and intrinsic or functional renal injury. Accurate assessment of kidney function is essential, as serum creatinine and estimated glomerular filtration rate (eGFR) calculations directly influence MELD-based transplant allocation, eligibility for simultaneous liver–kidney transplantation (SLKT), and clinical decisions such as drug dosing and peri-transplant immunosuppression strategies. However, creatinine-based assessments are fundamentally limited in cirrhosis due to reduced creatinine production, sarcopenia, expanded volume of distribution, increased tubular secretion, and assay interference from hyperbilirubinemia, resulting in frequent overestimation of true GFR. Alternative methods, including cystatin C-based equations, combined creatinine–cystatin C equations, timed urine clearances, and direct GFR measurement using exogenous filtration markers (iohexol, iothalamate), offer potential advantages but also carry important limitations, particularly in decompensated disease with ascites or inflammation. Newer cirrhosis-specific eGFR equations such as the GRAIL and Royal Free Hospital formulas attempt to address these shortcomings, yet validation studies demonstrate inconsistent accuracy across patient cohorts. This review summarizes the pathophysiologic contributors to renal dysfunction in cirrhosis, evaluates the performance and pitfalls of existing kidney function assessment tools, and highlights the ongoing need for reliable, validated methods tailored to this unique population. Until improved approaches are widely accessible, serum creatinine remains the most practical—albeit imperfect—marker guiding clinical decision-making in cirrhotic patients.

Abstract Roux‐en‐Y gastric bypass (RYGB) surgery is a highly effective technique for treating obesity. However, it may result in nutritional deficiencies. Here we report the case of a 55‐year‐old woman presenting with chronic diarrhea lasting 2 years, accompanied by lower limb paresthesia, macrocytic anemia, leukopenia, and thrombocytopenia. Her medical history included hypothyroidism treated with levothyroxine, and RYGB surgery performed in 2014, with intermittent micronutrient supplementation. The patient developed copper and zinc deficiencies. To our knowledge, this is the first report of a patient presenting with both deficiencies simultaneously with pancytopenia 10 years after RYGB. This case underscores the need to verify adherence to existing preoperative screening recommendations involving preoperative micronutrient measurements to assess micronutrient deficiency risks and multidisciplinary postoperative follow‐up, the importance of monitoring micronutrient levels, close follow‐up of both symptomatic and asymptomatic patients and evaluating adherence to supplementation regimens.

Acquired angioedema due to C1-inhibitor deficiency (AAE-C1INH) is a rare condition characterized by the localized swelling of the deeper skin layers and mucous membranes, especially the face, lips, tongue, throat, and gastrointestinal tract. AAE-C1INH is strongly associated with lymphoproliferative disorders, although it can also be linked to autoimmune conditions, solid tumors, infections, or even occur without an identifiable cause. We present the case of a 45-year-old female patient with complaints of recurrent abdominal pain, bloating, and joint swelling. Laboratory testing showed decreased C1q and C4 complement levels, and C1 esterase inhibitor levels, indicative of AAE-C1INH. Further work up confirmed a diagnosis of extranodal marginal zone lymphoma with involvement of the bone marrow and spleen. Treatment with rituximab led to resolution of angioedema symptoms and almost complete remission of underlying lymphoma. This case underscores the importance of evaluating an underlying lymphoproliferative disorder in AAE-C1INH. Therefore, the early participation of a multidisciplinary team including specialists in immunology, hematology, and oncology is necessary for appropriate management.

Portal vein thrombosis in non-cirrhotic individuals, although uncommon, is an increasingly explored condition that affects mainly young people, consequently representing a significant disease burden. Reports primarily including western European populations have recently shed light regarding the pathophysiology, risk factors, natural history, treatment, and prognosis of this entity. Underlying predisposing conditions are documented in ~70% of cases, encompassing local risk factors, inherited and acquired thrombophilia, cancer, and systemic inflammatory conditions. Non-cirrhotic portal vein thrombosis can cause significant portal hypertension in the acute setting, but, more frequently, significant portal hypertension-related complications arise when the condition becomes chronic and portosystemic collaterals develop, increasing the risk for variceal bleeding and ascites. The diagnostic approach to screen for underlying thrombophilia remains a challenge, and recommendations in this regard, although scarce and backed by scarce evidence, have changed notably in the last years, leaning toward a universal screen in patients who develop this condition without a clear provoking factor. Recently, studies have shown that long-term anticoagulation may be appropriate even in the absence of clear provoking factors or underlying thrombophilia. Future studies should address which patients may benefit from this approach, which patients may not need it, and what the most appropriate strategies are to approach patients who do not recover portal vein patency with anticoagulation to further prevent portal hypertension-related complications.

Autoimmune hepatitis is an immune-mediated inflammatory condition of the liver of undetermined cause that affects both sexes, all ages, races, and ethnicities. Its clinical presentation can be very broad, from having an asymptomatic and silent course to presenting as acute hepatitis, cirrhosis, and acute liver failure potentially requiring liver transplantation. The diagnosis is based on histological abnormalities (interface hepatitis), characteristic clinical and laboratory findings (increased aspartate aminotransferase, alanine aminotransferase, and serum IgG concentration), and the presence of one or more characteristic autoantibodies. The large heterogeneity of these clinical, biochemical, and histological findings can sometimes make a timely and proper diagnosis a difficult task. Treatment seeks to achieve remission of the disease and prevent further progression of liver disease. First-line therapy includes high-dose corticosteroids, which are later tapered to decrease side effects, and azathioprine. In the presence of azathioprine intolerance or a poor response to the standard of care, second-line therapy needs to be considered, including mycophenolate mofetil. AIH remains a diagnostic and therapeutic challenge, and a further understanding of the pathophysiological pathways of the disease and the implementation of randomized controlled trials are needed.