Jarrett Santorelli, MD and Leslie Kobayashi, MD Division of Trauma, Acute Care Surgery, Surgical Critical Care and Burns, University of California San Diego, San Diego, CA, USA It is well known that nutrition has a central prognostic and therapeutic role in the management of patients with liver disease. Based on available published data, patients should have an energy intake of 30–35 kcal/kg/d and a protein intake of 1.2–1.5 g/kg/d. In a well‐conducted prospective trial measuring total body nitrogen, the nocturnal administration of oral nutritional supplements has been shown to be more effective in improving total body protein status than daytime oral nutritional supplements. Patients undergoing liver transplantation who are underweight or severely obese experience significantly higher rates of morbidity and mortality in comparison with patients in the middle BMI categories. Across different eras of liver transplantation, underweight and severe obesity are independent predictors of death in a multivariable analysis. Despite some promising small studies of immuno‐enhanced nutritional supplementation particularly in the burn ICU population, there is no good evidence to support their use in patients with end‐stage liver disease (ESLD) either pre‐ or post‐transplant. Anti‐inflammatory oils have also not been demonstrated to have any substantial benefit when compared to standard enteral nutrition. While there is definite evidence that enteral nutrition is superior to parenteral nutrition, PEG tubes are not recommended in patients with ESLD. The presence of ascites, abdominal wall, gastric and esophageal varices, as well as the coagulopathy present in many ESLD patients, makes the risks of placement and infection/dislodgement after placement prohibitive. Answer: C Dick AAS, Spitzer AL, Seifert CF, et al. Liver transplantation at the extremes of the body mass index. Liver Transplantation 2009; 15(8): 968–977. Plauth M, Bernal W, Dasarathy S, et al. ESPEN guidelines on clinical nutrition in liver disease. Clinical Nutrition 2019; 38(2): 485–521. Venous thromboembolism (VTE), with deep vein thrombosis (DVT) and pulmonary embolism (PE) as the most common manifestations, is a serious and potentially fatal complication of major abdominal surgery and is estimated to occur in 5–10% of patients. The most common risk factors for VTE are hospitalization (52%), cancer (48%), and surgery (42%). Numerous risk factors for VTE exist in patients who undergo orthotopic liver transplantation (OLT) including critical illness, prolonged periods of bedrest, indwelling central venous catheters, and veno‐venous bypass. Recent studies have also demonstrated an increased risk of VTE in transplant recipients with diabetes, previous history of VTE, end‐stage renal disease (ESRD), patients discharged to rehabilitation centers, receiving factor VII during surgery, or having postoperative pneumonia. A marked reduction of both procoagulant factors (II, V, VII, IX, X, XI, XII), anticoagulant factors (anti‐thrombin III, protein C, and protein S), an increase in von Willebrand factor (vWF), and a reduced level of ADAMTS13 are the specific features of cirrhosis and bring the patient to a new hemostatic balance. Elevated tissue plasminogen activator and a deficiency of thrombin‐activatable fibrinolysis inhibitor have been associated with laboratory changes typical of hyperfibrinolysis and an increased risk of bleeding. However, cirrhosis has also been associated with reduced fibrinolysis, as shown by the decreased plasminogen and increased plasminogen activator inhibitor. The contrasting results explain the ongoing debate regarding the absence or presence of a hyperfibrinolytic state in patients with liver disease, even if the balance of fibrinolysis is probably restored by the parallel changes in profibrinolytic and antifibrinolytic drivers. In addition, patients may also suffer from microvascular consumption causing further decreases in AT‐III levels. Despite this balanced hemostatic condition, cirrhosis results in the prolongation of standard coagulation tests, which usually do not analyze the complex interplay between pro‐ and anticoagulants and thus do not provide an accurate evaluation of the alteration in the in vivo hemostatic balance. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and International Normalized Ratio (INR) provide only a measure of procoagulant factors and are insensitive to the plasma levels of anticoagulant factors, so they are unreliable to depict the hemostatic status of patients with end‐stage liver disease. Compared to patients undergoing other major abdominal surgeries, OLT patients have comparable to somewhat lower rates of VTE. Chemoprophylaxis, when utilized, has been associated with reduced risk of VTE after OLT. Chemoprophylaxis has also been associated with lower rates of portal vein thrombosis. Chemoprophylaxis has not been associated with higher mortality or complications. Answer: B Feltracco P, Barbieri S, Cillo U, et al. Perioperative thrombotic complications in liver transplantation. World Journal of Gastroenterology 2015; 21(26): 8004–8013. Nachal R, Subramanian R, Karvellas CJ, et al. Guidelines for the management of adult acute and acute‐on‐chronic liver failure in the ICU: cardiovascular, endocrine, hematologic, pulmonary and renal considerations: executive summary. Critical Care Medicine 2020; 48(3): 415–419. Salami A, Qureshi W, Kuriakose P, et al. Frequency and predictors of venous thromboembolism in orthotopic liver transplant recipients: a single‐center retrospective review. Transplantation Proceedings 2013; 45(1): 315–319. Yip J, Bruno DA, Burmeister C, et al. Deep vein thrombosis and pulmonary embolism in liver transplant patients: risks and prevention. Transplantation Direct 2016; 2(4):e68. Invasive fungal disease (IFD) is one of the critical opportunistic infections afflicting solid organ transplant (SOT) recipients. IFD contributes to relatively high morbidity and mortality compared to its low incidence, due to multiple causes, which include fungal virulence and delayed diagnosis in SOT patients. While still uncommon, incidence of IFD is increasing slightly over time. The incidence of IFD among kidney transplant recipients is commonly known to be the lowest among all SOT recipients, reported as 1–10%. The patients with highest risk for IFD are small bowel, lung, and liver recipients. The period of the highest risk for the development of IFD is known to be the period of intense immunosuppression, from one to six months after SOT. Recent studies reported that the majority of IFD cases developed later than six months after kidney transplantation (KT). Candida and Aspergillus species are the most common organisms, with non‐albicans species increasing in frequency. Answer: D Lum L, Lee A, Vu M, Strasser S, Davis R . Epidemiology and risk factors for invasive fungal disease in liver transplant recipients in a tertiary transplant center. Transplant Infectious Disease 2020; e13361. Pappas PG, Alexander BD, Andes DR, et al. Invasive fungal infections among organ transplant recipients: results of the Transplant‐Associated Infection Surveillance Network (TRANSNET). Clinical Infectious Diseases 2010: 50(8): 1101–1111. Seok H, Huh K, Cho SY, et al. Invasive fungal diseases in kidney transplant recipients: risk factors for mortality. Journal of Clinical Medicine 2020; 9(6):1824. This patient is demonstrating the most worrisome toxicity of tacrolimus, which is nephrotoxicity. Other typical symptoms of calcineurin inhibitor (CNI) toxicity include altered mental status, hypertension, hyperglycemia, and hyperlipidemia. CNIs are both the savior and Achilles heel of kidney transplantation. Though CNI have significantly reduce rates of acute rejection, their numerous toxicities can plague kidney transplant recipients. CNIs function as immunosuppressants by blocking T‐cell activation by binding to specific receptors and blocking calcineurin, a calcium‐dependent phosphatase within T‐cells. Though CNIs have been successful in preventing acute kidney transplant rejection, their use has been described as a significant contributing factor in acute and chronic allograft injury and ultimately allograft loss – with virtually universal presence of CNI nephrotoxicity on allograft biopsy by 10 years after kidney transplant. CNIs are metabolized by cytochrome P450 3A4 (CYP3A4) in both the liver and small intestine, and clearance is primarily from biliary excretion and fecal elimination. Any medications that inhibit CYP3A4 will increase drug concentrations, and in contrast, medications that induce CYP3A4 will decrease drug concentrations. Azole antifungals like fluconazole are commonly encountered inhibitors of CYP3A4 and will result in increased levels of tacrolimus and increased toxicity. While steroids, narcotics, and gabapentin may all contribute to altered mental status and increased somnolence, they are unlikely to affect renal function and both narcotics and gabapentin are more likely to result in decreased blood pressure than hypertension. Mycophenolate mofetil (MMF) is a first‐line drug in the maintenance of immunosuppression after solid organ transplant and has the benefit of low toxicity and minimal side effect profile. Side effects of MMF include gastrointestinal distress and pancytopenia. In contrast to CNIs, nephrotoxicity and neurotoxicity are rare with MMF. Table 22.1 Common pharmacologic CYP3A4 inhibitors and inducers. Answer: C Farouk SS, Rein JL . The many faces of calcineurin inhibitor toxicity‐ What the FK? Advances in Chronic Kidney Disease 2020; 27(1): 56–66. Vanhove T, Annaert P, Kuypers DR . Clinical determinants of calcineurin inhibitor disposition: a mechanistic review. Drug Metabolism Reviews 2016; 48(1):88–112. Both tacrolimus and cyclosporine are classified as calcineurin inhibitors (CNIs) and are often used in maintenance immunosuppression following SOT. Tacrolimus binds to FK binding protein‐12 and blocks proliferation of calcineurin, preventing interleukin‐2 (IL‐2) expression/production, thus preventing an immune response from lymphocytes. Tacrolimus is superior to cyclosporine in increasing patient and graft survival. Fewer episodes of acute cellular rejection and steroid‐resistant rejection have also been seen with tacrolimus use in the first‐year post‐transplant compared to cyclosporine. Tacrolimus is preferred at most transplant centers because of its greater potency and improved cardiovascular side‐effect profile. While cyclosporine and tacrolimus have similar nephrotoxicity, tacrolimus has a greater diabetogenic effect than cyclosporine. Based on low‐quality evidence, basiliximab induction may decrease mortality and graft failure compared to glucocorticosteroid induction in people undergoing liver transplantation. Based on low‐quality evidence from a single small trial from direct comparison, tacrolimus plus sirolimus increase mortality and graft loss at maximal follow‐up compared with tacrolimus. Answer: A Best LMJ, Leung J, Freeman SC, et al. Induction immunosuppression in adults undergoing liver transplation: a network meta‐analysis. Cochrane Database of Systematic Reviews 2020; 1(1): CD013203. Haddad EM, McAlister VC, Renouf E, et al. Cyclosporin versus tacrolimus for liver transplanted patients. Cochrane Database of Systematic Reviews 2006; 18(4):CD005161. Rodrique‐Peralvarez M, Guerrero‐Misas M, thorburn D, et al. Maintenance immunosuppression for adults undergoing liver transplantation: a network meta‐analysis. Cochrane Database of Systematic Reviews 2017; 3(3):CD011639.
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Transplantation, Immunology, and Cell Biology
Inhibitors
Inducers
Cannabidiol
Carbamazepine
Diltiazem
Phenytoin
Verapamil
Phenobarbital
Erythromycin
Rifampin
Ketoconazole
Rifabutin
Fluconazole
Efavirenz
Clotrimazole
Dexamethasone
Ritonavir