Differential Diagnosis for Post-Kidney Transplant Patient with Abdominal Pain

Single Most Likely Diagnosis

• Tacrolimus-induced abdominal pain: Tacrolimus, an immunosuppressive drug commonly used in transplant patients, can cause abdominal pain as a side effect. Given the patient's recent kidney transplant and the absence of other findings on the abdominal CT scan, this is a plausible explanation for her symptoms.

Other Likely Diagnoses

• Diverticulitis: Although the abdominal CT scan did not show any pathology, diverticulitis can sometimes be missed on imaging, especially if it's a mild case. The patient's known history of diverticular disease makes this a possible diagnosis.
• Constipation: Immunosuppressive drugs and decreased mobility can contribute to constipation, which is a common cause of abdominal pain.
• Gastroesophageal reflux disease (GERD): GERD can cause abdominal pain and is common in the general population. The patient's symptoms could be related to GERD, especially if she has other risk factors.

Do Not Miss Diagnoses

• Rejection of the transplanted kidney: Although the CT scan showed a normal transplanted kidney, rejection can sometimes present with non-specific symptoms like abdominal pain. It's crucial to monitor the patient's kidney function and consider a biopsy if there's any suspicion of rejection.
• Intra-abdominal infection: Immunocompromised patients are at higher risk for infections, which can be life-threatening if not promptly treated. An intra-abdominal infection, such as peritonitis or an abscess, could be a possible diagnosis.
• Bowel obstruction: A bowel obstruction can be a life-threatening condition that requires prompt surgical intervention. Although the CT scan did not show any evidence of obstruction, it's essential to consider this diagnosis, especially if the patient's symptoms worsen.

Rare Diagnoses

• Cytomegalovirus (CMV) infection: CMV infection can cause abdominal pain and is more common in immunocompromised patients. However, this diagnosis would be less likely without other symptoms like fever or leukopenia.
• Post-transplant lymphoproliferative disorder (PTLD): PTLD is a rare but potentially life-threatening condition that can occur in transplant patients. Abdominal pain could be a presenting symptom, but this diagnosis would be unlikely without other findings like lymphadenopathy or masses on imaging.