I’ve cared for kidney, heart, liver and bone marrow transplants.
There are two types of rejection. The more common type happens relatively slow, over a matter of days, usually, and sometimes can be reversed. I’ll say more about that process in a sec.
The second type is hyper-rejection. It happens when a poorly matched organ is implanted. In kidney transplant hyper-rejection, the organ turns black within a few seconds of the clamps being removed from the blood vessels. It must be removed since it’s just dead tissue, and would cause massive sepsis.
With the more common type, the first thing the nurse would find (yes, it’s the nurse that makes all the early observations.) would be a drop in urine output and an increase in blood pressure.
There is usually microscopic blood in the urine for a day or more after surgery, but, urine becoming visibly bloody is another sign. She would then draw some lab work to confirm rejection. The doctor would then increase the doses of anti-rejection drugs and possibly add others. If the kidney continued to fail, it would have to be removed, even if it had some slight function left, to prevent hypertension. (the kidney produces renin and angiotension that help regulate blood pressure.)
Hyper-rejection can happen with heart and liver transplants too, but less often, due to the fact that a minor mismatch in a kidney may be tolerated, but if it isn’t the bad bean can be removed without the patient dying. Not so with heart or liver, so the crossmatching process is much tighter.
A heart that’s being rejected causes a drop in blood pressure, a slowing of the heart rate, arrhythmias, labs are the best indicator of early rejection, so they’re done frequently.
With the liver too, labs are the earliest indicators. Uncontrollable bleeding is usually the first physical sign.
Bone marrow transplant is very different, in that, unlike the grafted kidney being rejected by the body, the graft rejects the host. (Called Graft vs Host Disease, or GVHD) The three systems affected first, and most dramatically, are skin, GI tract and liver. The skin can slough entirely, leaving the patient with the equivalent of third degree burns over 100% of their body. The GI tract does the same causing the patient to bleed from their bowel, sometimes as much as 12 liters per 8 hours. Liver GVHD causes fulminant liver failure. GVHD can also present in the lungs causing Adult Respiratory Distress Syndrome (ARDS) where in the lungs become so stiff, they can no longer exchange.
As far as who pays, the patient’s insurance* pays for everything. (you hope.) Rejection isn’t a medical error, so who else would be expected to pay? In fact, the organ retrieval is partially paid by the recipient’s insurer.
*Some life insurance policies have a catastrophic illness clause, that will help pay for transplantation.