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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor=William J Gibson
|QuestionAuthor=William J Gibson (Reviewed by  {{YD}})
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Infectious Disease
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Oncology, Infectious Disease
|MainCategory=Pharmacology
|Prompt=A 75-year-old woman undergoes total body irradiation followed by autologous bone marrow transplant for Chronic Lymphocytic Leukemia.  Approximately one month following her transplant, she develops bloody stools, diarrhea, fever, abdominal pain and dysphagia.  Colonoscopy reveals several ulcers and pp65 antigen assay is positive. Which of the following treatments is most appropriate?
|SubCategory=Infectious Disease
|Explanation=The patient in this vignette is suffering from cytomegalovirus (CMV) associated colitis.  CMV colitis is associated with ulcerating lesions that may occur throughout the entire digestive tract, from the esophagus to the colon.  The diagnosis of CMV colitis is based on serology, CMV antigen testing (pp65 antigen) and colonscopy with biopsy.  CMV colitis should be treated with ganciclovir, a guanosine analogue that is converted to the active anti-metabolite by a virally encoded kinase.
|Prompt=A 62-year-old woman undergoes total body irradiation followed by autologous bone marrow transplant for Chronic Lymphocytic Leukemia (CLL).  Approximately one month following her transplant, she develops bloody stools, diarrhea, fever, abdominal pain, and dysphagia.  Colonoscopy reveals several ulcers, and pp65 antigen assay is positive. Which of the following treatments is most appropriate to treat this patient's condition?
 
|Explanation=The patient in this vignette is suffering from cytomegalovirus (CMV)-associated colitis.  CMV colitis is associated with ulcerating lesions that may occur throughout the entire digestive tract.  The diagnosis of CMV colitis is based on serology, CMV antigen testing (pp65 antigen) and colonoscopy with biopsy.  CMV colitis should be treated with [[ganciclovir]], a guanosine analogue that is converted to its active anti-metabolite by a virally encoded kinase.
Educational Objective:  CMV colitis should be treated with ganciclovir, a guanosine analogue that is converted to the active anti-metabolite by a virally encoded kinase.
 
References:
 
First Aid 2013 page 188 (Ganciclovir)
 
|AnswerA=Metronidazole
|AnswerA=Metronidazole
|AnswerAExp='''Incorrect:''' Metronidazole would be the appropriate treatment for Clostridium difficile colitis.  This patient is suffering from CMV colitis.
|AnswerAExp=[[Metronidazole]] would be the appropriate treatment for ''Clostridium difficile'' colitis.  This patient is suffering from CMV colitis.
|AnswerB=Ganciclovir
|AnswerB=Ganciclovir
|AnswerBExp='''Correct:'''  Ganciclovir is a guanosine analogue that is converted to the active anti-metabolite by a virally encoded kinase.  It is used for the treatment of CMV infections.
|AnswerBExp=[[Ganciclovir]] is a guanosine analogue that is converted to its active anti-metabolite by a virally encoded kinase.  It is indicated for the treatment of CMV infections.
|AnswerC=Vancomycin
|AnswerC=Vancomycin
|AnswerCExp='''Incorrect:''' Oral vancomycin would be an appropriate treatment for Clostridium difficile colitis.  This patient is suffering from CMV colitis.
|AnswerCExp=Oral [[vancomycin]] would be an appropriate treatment for ''Clostridium difficile'' colitis.  This patient is suffering from CMV colitis.
|AnswerD=Cyclosporine
|AnswerD=Cyclosporine
|AnswerDExp='''Incorrect:''' Cyclophosphamide is an immunosuppressive agent used for prophylaxis against graft-versus-host-disease (GVHD).  While GVHD can manifest as early as one month after transplant and cause damage to the gastrointestinal tract, the clinical scenario strongly suggests CMV colitis.  Furthermore, we one may be assured of an infectious etiology by the mention of pp65 antigen.
|AnswerDExp=[[Cyclosporine]] is an immunosuppressive agent used for prophylaxis against graft-versus-host-disease (GVHD).  While GVHD can manifest as early as one month following transplant and cause damage to the gastrointestinal tract, the clinical features strongly suggest CMV colitis.
|AnswerE=Acyclovir
|AnswerE=Acyclovir
|AnswerEExp='''Incorrect:'''  While acyclovir shares a similar mechanism of action to ganciclovir, acyclovir is ineffective for CMV colitis because CMV does not contain a thymidine kinase.
|AnswerEExp=While [[acyclovir]] shares a similar mechanism of action to ganciclovir, acyclovir is not effective to treat CMV infections because CMV does not contain a thymidine kinase.
|EducationalObjectives=CMV colitis should be treated with ganciclovir, a guanosine analogue that is converted to its active anti-metabolite by a virally encoded kinase.
|References=First Aid 2015 page 193.
|RightAnswer=B
|RightAnswer=B
|WBRKeyword=CMV, Bone marrow transplantation, Cancer, Leukemia, Ulcer, Graft, Transplant, CLL, Chronic lymphocytic leukemia,  
|WBRKeyword=CMV, Cytomegalovirus, Bone marrow transplantation, BMT, Cancer, Leukemia, Ulcer, Graft, Transplant, CLL, Chronic lymphocytic leukemia,
|Approved=Yes
|Approved=Yes
}}
}}

Latest revision as of 02:09, 28 October 2020
Author [[PageAuthor::William J Gibson (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Pharmacology
Sub Category SubCategory::Infectious Disease
Prompt [[Prompt::A 62-year-old woman undergoes total body irradiation followed by autologous bone marrow transplant for Chronic Lymphocytic Leukemia (CLL). Approximately one month following her transplant, she develops bloody stools, diarrhea, fever, abdominal pain, and dysphagia. Colonoscopy reveals several ulcers, and pp65 antigen assay is positive. Which of the following treatments is most appropriate to treat this patient's condition?]]
Answer A AnswerA::Metronidazole
Answer A Explanation [[AnswerAExp::Metronidazole would be the appropriate treatment for Clostridium difficile colitis. This patient is suffering from CMV colitis.]]
Answer B AnswerB::Ganciclovir
Answer B Explanation [[AnswerBExp::Ganciclovir is a guanosine analogue that is converted to its active anti-metabolite by a virally encoded kinase. It is indicated for the treatment of CMV infections.]]
Answer C AnswerC::Vancomycin
Answer C Explanation [[AnswerCExp::Oral vancomycin would be an appropriate treatment for Clostridium difficile colitis. This patient is suffering from CMV colitis.]]
Answer D AnswerD::Cyclosporine
Answer D Explanation [[AnswerDExp::Cyclosporine is an immunosuppressive agent used for prophylaxis against graft-versus-host-disease (GVHD). While GVHD can manifest as early as one month following transplant and cause damage to the gastrointestinal tract, the clinical features strongly suggest CMV colitis.]]
Answer E AnswerE::Acyclovir
Answer E Explanation [[AnswerEExp::While acyclovir shares a similar mechanism of action to ganciclovir, acyclovir is not effective to treat CMV infections because CMV does not contain a thymidine kinase.]]
Right Answer RightAnswer::B
Explanation [[Explanation::The patient in this vignette is suffering from cytomegalovirus (CMV)-associated colitis. CMV colitis is associated with ulcerating lesions that may occur throughout the entire digestive tract. The diagnosis of CMV colitis is based on serology, CMV antigen testing (pp65 antigen) and colonoscopy with biopsy. CMV colitis should be treated with ganciclovir, a guanosine analogue that is converted to its active anti-metabolite by a virally encoded kinase.

Educational Objective: CMV colitis should be treated with ganciclovir, a guanosine analogue that is converted to its active anti-metabolite by a virally encoded kinase.
References: First Aid 2015 page 193.]]

Approved Approved::Yes
Keyword WBRKeyword::CMV, WBRKeyword::Cytomegalovirus, WBRKeyword::Bone marrow transplantation, WBRKeyword::BMT, WBRKeyword::Cancer, WBRKeyword::Leukemia, WBRKeyword::Ulcer, WBRKeyword::Graft, WBRKeyword::Transplant, WBRKeyword::CLL, WBRKeyword::Chronic lymphocytic leukemia
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