Question

A 55-year-old woman undergoes allogeneic hematopoietic stem cell transplantation from an HLA- matched, unrelated donor for treatment of acute myeloid leukemia. She received conditioning chemotherapy prior to the transplantation, and her immediate post-transplant course was uncomplicated. However, 3 weeks after the transplant, the patient develops worsening crampy abdominal pain and diarrhea. The diarrhea is watery and persistent, even at night, with output up to 3 liters daily. No particular food makes the symptoms better or worse. Medications include tacrolimus, prophylactic acyclovir, trimethoprim-sulfamethoxazole, and voriconazole. The patient has no other chronic medical conditions. She has been in the hospital since the transplantation and is on a low-microbial diet. Physical examination shows generalized maculopapular rash. Stool testing for Clostridioides (formerly Clostridium) difficile and PCR testing for cytomegalovirus are negative.

Which of the following is the most likely cause of this patient's diarrhea?
A Antibody-dependent cellular cytotoxicity
B CD8+ T-lymphocyte mediated injury
C Cryptosporidium parvum infection
D Delayed toxicity of conditioning chemotherapy
E Post-transplant lymphoproliferative disorder

Answer 1

The most likely cause of the 55-year-old patient's symptoms after stem cell transplantation is CD8+ T-lymphocyte mediated injury, commonly known as graft-versus-host disease. Other potential causes are less likely due to a negative stool test for Clostridioides difficile, PCR test for cytomegalovirus, and the concurrent presence of a generalized rash. Option B is correct.

Step-by-step explanation:

In the case of the 55-year-old woman who underwent an allogeneic hematopoietic stem cell transplantation and developed worsening crampy abdominal pain, diarrhea, and a maculopapular rash, the most likely cause of her symptoms is CD8+ T-lymphocyte mediated injury. This condition is often referred to as graft-versus-host disease (GVHD), which is a complication of allogeneic stem cell transplantation. GVHD occurs when the donated immune cells recognize the recipient's tissues as foreign and attack them, leading to symptoms such as those described.

While other potential causes such as infection by Cryptosporidium parvum or delayed toxicity due to conditioning chemotherapy could lead to diarrhea, the presence of a generalized rash along with the gastrointestinal symptoms makes GVHD a more likely diagnosis. Moreover, the negative stool tests for Clostridioides difficile and the PCR test for cytomegalovirus make infectious causes less likely.

The patient's immunosuppressed state due to chemotherapy and the use of immunosuppressive medication like tacrolimus also increase the risk of developing GVHD. The patient should be evaluated and managed by the transplant team for prompt treatment of GVHD to prevent further complications.