by Andrea Houghton, MPH, RHIA, CCS, CCS-P, CDIP
My last blog post discussed how bone marrow and stem cell transplants are both essentially stem cell transplants; the difference is just where the stem cells come from.
As a reminder: if the stem cells are collected from bone marrow, the procedure is a bone marrow transplant whereas if the stem cells are collected from the peripheral bloodstream, the procedure is a stem cell transplant.
One potential serious complication of stem cell transplants when the stem cells are collected from another individual (allogeneic) is graft-versus-host disease (GvHD). Donated stem cells (the “graft” of the disease name) contain T cells that work to help destroy cancer cells but they may also attack the patient’s own healthy tissues and organs (the “host” of the disease name). The reason the transplanted T cells attack the patient’s own tissues and organs is because the donor T cells do not recognize the genetic markers on the cells in the transplant recipient. These genetic markers are called human leukocyte antigens (HLA). Because the T cells don’t recognize the HLA on the cells of the recipient, they activate the immune system to destroy the cells, causing the organ damage and/or organ failure of GvHD.
There are two forms of GvHD: acute and chronic. Acute GvHD is observed within the first 100 days post-transplant and is characterized by damage to the liver, skin (rash), mucosa and the gastrointestinal tract. Research has also shown that acute GvHD can also target the bone marrow and thymus as well as the lungs in the form of pneumonitis. Chronic GvHD, which is observed after the first 100 days post-transplant, can also attack the same organs, but can also cause damage to the connective tissue and exocrine glands.
The incidence of GvHD in stem cell transplant patients is not rare. Reported incidence rates of patients undergoing allogeneic stem cell transplants developing acute GvHD range between 9% to as high as 50% while the rates for chronic GvHD are between 6% to 80%. Immunosuppressive drugs alone or in combination with steroids after the transplant have proven effective in reducing the incidence and severity of GvHD.
Understanding what GvHD is will allow a coder to capture this diagnosis appropriately. GvHD is a complication of the allogeneic stem cell/bone marrow transplant so the appropriate diagnosis code would be the transplant complication first followed by the appropriate code for the GvHD:
T86.09 Other complications of bone marrow transplant
T86.5 Complications of stem cell transplant
Along with the appropriate code for the GvHD:
D89.810 Acute graft-versus-host disease
D89.811 Chronic graft-versus-host disease
D89.812 Acute on chronic graft-versus-host disease
D89.813 Graft-versus-host disease, unspecified