Flashcards in Pestana Chap 13 - Organ Transplantation Deck (12)
Are brain-dead patients organ donor candidates? Can patients with specific infections (like hepatitis) be donors? Can patients with metastatic cancer be donors?
1) Virtually all brain-dead patients are potential candidates, regardless of age
2) Donors with specific infections (like hepatitis) can be used for recipients who have the same disease
3) Even donors with metastatic cancer can donate corneas
What is the general rule for choosing a potential donor?
The general rule for regular physicians is that all potential donors are referred to the harvesting teams, and they will exclude the few that cannot be used at all
What is the only absolute contraindication to organ donation?
A positive HIV status
What are 3 ways in which transplant rejection can occur?
3) Chronic rejection
What is hyperacute rejection? What is it caused by? What is it prevented by?
1) Hyperacute rejection is a vascular thrombosis that occurs within minutes of reestablishing blood supply to the organ
2) It is caused by preformed antibodies
3) It is prevented by ABO matching and lymphocytotoxic crossmatch, and thus it is not seen clinically
When does acute rejection occur? Do episodes occur even with immunosuppression?
1) After the first 5 days, and usually within the first 3 months
What do current maintenance protocols for acute rejection include? What is suggestive of acute rejection and what confirms it?
1) Tacrolimus and mycophenolate mofetil, with or without prednisone
2) Signs of organ dysfunction suggest acute rejection, and biopsy confirms it
In terms of liver transplantation, are technical problem or immnologic rejection more common? What is therefore the first order of business when liver function deteriorates after transplant (rising gamma-glutamyltransferase [GGT], alkaline phosphatase, and bilirubin?
1) Technical problems
2) Rule out biliary obstruction by ultrasound and vascular thrombosis by Doppler
What is done in the case of heart transplant to allow effective therapy in the event of deterioration and why?
In the case of the heart, signs of functional deterioration occur too late to allow effective therapy, thus routine ventricular biopsies (by way of the jugular, superior vena cava, and right atrium) are done at set intervals
What is first line therapy for acute rejection? What if this is unsuccessful and what is a problem with this alternate therapy? What alternative is tolerated better?
1) Steroid boluses
2) If unsuccessful, antilymphocyte agents (OKT3) have been used, but their high toxicity is a problem
3) Newer antithymocyte serum is tolerated better
What efforts are under way to diagnose rejection without the need for biopsies?
Efforts are under way to come up with cellular MRI as a noninvasive way to diagnose rejection, without the need for biopsies