12 Transplant Flashcards
A 62-year-old man who had a motorcycle accident has been in a coma for several weeks. He is on a respirator, has had pneumonia on and off, has been on vasopressors, and shows no signs of neurologic improvement. The family inquires about brain death and possible organ donation.
The rule now is that all potential donors are referred to the local organ harvesting organization. Donors with specific infections (such as hepatitis) can be used for recipients with the same infection. Even donors with metastatic cancer are eligible for eye donation. A positive HIV status remains the only absolute contraindication to a patient serving as an organ donor.
I. Ten days after liver transplantation, levels of g-glutamyltransferase (GGT), alkaline phosphatase, and bilirubin begin to go up. There is no ultrasound evidence of biliary obstruction or Doppler evidence of vascular thrombosis.
II. On the third week after a closely matched renal transplant, there are early clinical and laboratory signs of decreased renal function.
III. Two weeks after a lung transplant, the patient develops fever, dyspnea, hypoxemia, decreased FEV1, and interstitial infiltrate on chest x-ray.
There are 3 kinds of rejection. Hyperacute rejection happens within minutes of re-establishing blood supply, produces thrombosis, and is caused by preformed antibodies. ABO matching and lymphocytotoxic crossmatch prevents it, and thus we do not see it clinically—and you will not encounter it in the USMLE.
Acute rejection is the one we deal with all the time. It occurs after the first 5 days, and usually within the first few months. Signs of organ dysfunction (as in these vignettes) suggest it, but biopsy is what confirms it. In the case of the heart, there are no early clinical signs; thus biopsies there are done routinely at set intervals. Once diagnosed, the first line of therapy is steroid boluses. If unsuccessful, antilymphocyte agents are used (anti-thymocyte serum).
Several years after a successful (renal, hepatic, cardiac, pulmonary) transplantation, there is gradual, insidious loss of organ function.
This is the third form: chronic rejection. Poorly understood, and irreversible. We have no treatment
for it, but the correct answer for such vignette would be to do biopsy. Late acute rejection episodes could be the problem, and we can treat those.
