WBR0156: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| Line 21: | Line 21: | ||
|SubCategory=Musculoskeletal/Rheumatology | |SubCategory=Musculoskeletal/Rheumatology | ||
|Prompt=A 43-year-old woman presents to her primary care physician for increasingly severe joint pain and fatigue over the past three months. She feels significant joint stiffness in the morning, which improves throughout the day. She describes her pain as a persistent, dull pain that “hurts all over”. On physical examination, the physician notes mild joint swelling around the knee and ulnar deviation of the fingers. Laboratory testing reveals a positive ELISA for anti-IgG antibodies. The patient is started on a first-line disease-modifying drug, but three weeks later is found to be critically leukopenic after three weeks. Which of the following medications can be used to specifically reverse the effects of the administered drug? | |Prompt=A 43-year-old woman presents to her primary care physician for increasingly severe joint pain and fatigue over the past three months. She feels significant joint stiffness in the morning, which improves throughout the day. She describes her pain as a persistent, dull pain that “hurts all over”. On physical examination, the physician notes mild joint swelling around the knee and ulnar deviation of the fingers. Laboratory testing reveals a positive ELISA for anti-IgG antibodies. The patient is started on a first-line disease-modifying drug, but three weeks later is found to be critically leukopenic after three weeks. Which of the following medications can be used to specifically reverse the effects of the administered drug? | ||
|Explanation=The patient in this vignette is suffering from rheumatoid arthritis (RA), an autoimmune inflammatory disease which commonly presents as systemic joint pain. A positive rheumatoid factor (anti AgG antibody) is 80% sensitive and 90% specific for RA. RA is two to three times more prevalent in females than males. Rheumatoid arthritis tend to affect the MCP and PIP joint of the hand and spares the DIP. Swelling of the MCP joint can cause the ulnar deviation of the fingers seen in this patient. | |Explanation=The patient in this vignette is suffering from [[rheumatoid arthritis]] (RA), an autoimmune inflammatory disease which commonly presents as systemic joint pain. A positive rheumatoid factor (anti AgG antibody) is 80% sensitive and 90% specific for RA. RA is two to three times more prevalent in females than males. Rheumatoid arthritis tend to affect the MCP and PIP joint of the hand and spares the DIP. Swelling of the MCP joint can cause the [[ulnar deviation]] of the fingers seen in this patient. | ||
RA is treated with a combination of analgesics and disease-modifying antirheumatic drugs (DMARDs). The first-line disease modifying drug for RA is methotrexate. | RA is treated with a combination of analgesics and disease-modifying antirheumatic drugs (DMARDs). The first-line disease modifying drug for RA is methotrexate. | ||
| Line 28: | Line 28: | ||
'''Educational Objective:''' Leucovorin (folinic acid) can be used to “rescue” methotrexate toxicity. | '''Educational Objective:''' Leucovorin (folinic acid) can be used to “rescue” methotrexate toxicity. | ||
'''References:''' First Aid 2012 Page 399 | '''References:''' First Aid 2012 Page 399 | ||
|AnswerA=Infliximab | |AnswerA=Infliximab | ||
|AnswerAExp='''Incorrect:''' Infliximab is an antibody directed against TNF-alpha, indicated for use in Rheumatoid arthritis, Crohn’s disease and ankylosing spondylitis. All anti-TNF-alpha agents increase the risk of reactivation TB. While Infliximab can be used to treat Rheumatoid arthritis, it cannot rescue the toxic effects of methotrexate. | |AnswerAExp='''Incorrect:''' [[Infliximab]] is an antibody directed against TNF-alpha, indicated for use in Rheumatoid arthritis, Crohn’s disease and ankylosing spondylitis. All anti-TNF-alpha agents increase the risk of reactivation TB. While Infliximab can be used to treat Rheumatoid arthritis, it cannot rescue the toxic effects of methotrexate. | ||
|AnswerB=Leucovorin | |AnswerB=Leucovorin | ||
|AnswerBExp='''Correct:''' [[Leucovorin]] is equivalent to activated folinic acid. It can be administered to “rescue” the effects of [[Methotrexate]]. Methotrexate competitively inhibits folic acid binding to Dihydrofolate reductase, an enzyme responsible for the conversion of dihydrofolic acid to tetrahydrofolic acid. Leucovorin administration bypasses this step in thymidine synthesis and thereby reverses the effect of methotrexate. | |AnswerBExp='''Correct:''' [[Leucovorin]] is equivalent to activated folinic acid. It can be administered to “rescue” the effects of [[Methotrexate]]. Methotrexate competitively inhibits folic acid binding to Dihydrofolate reductase, an enzyme responsible for the conversion of dihydrofolic acid to tetrahydrofolic acid. Leucovorin administration bypasses this step in thymidine synthesis and thereby reverses the effect of methotrexate. | ||
|AnswerC=Vitamin K | |AnswerC=Vitamin K | ||
|AnswerCExp='''Incorrect:''' Vitamin K is used to reverse the effects of Warfarin. | |AnswerCExp='''Incorrect:''' Vitamin K is used to reverse the effects of [[Warfarin]]. | ||
|AnswerD=Protamine | |AnswerD=Protamine | ||
|AnswerDExp='''Incorrect:''' Protamine is used to reverse the effects of heparin. | |AnswerDExp='''Incorrect:''' [[Protamine]] is used to reverse the effects of [[heparin]]. | ||
|AnswerE=Naloxone | |AnswerE=Naloxone | ||
|AnswerEExp='''Incorrect:''' Naloxone is used to reverse the effects of morphine overdose. | |AnswerEExp='''Incorrect:''' [[Naloxone]] is used to reverse the effects of [[morphine]] overdose. | ||
|RightAnswer=B | |RightAnswer=B | ||
|WBRKeyword=Rheumatoid arthritis, RA, Methotrexate, Chemotherapy, Side effect, Myelosuppression, Leukopenia | |WBRKeyword=Rheumatoid arthritis, RA, Methotrexate, Chemotherapy, Side effect, Myelosuppression, Leukopenia | ||
|Approved=Yes | |Approved=Yes | ||
}} | }} | ||
Revision as of 12:50, 8 October 2013
| Author | PageAuthor::William J Gibson |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pharmacology |
| Sub Category | SubCategory::Musculoskeletal/Rheumatology |
| Prompt | [[Prompt::A 43-year-old woman presents to her primary care physician for increasingly severe joint pain and fatigue over the past three months. She feels significant joint stiffness in the morning, which improves throughout the day. She describes her pain as a persistent, dull pain that “hurts all over”. On physical examination, the physician notes mild joint swelling around the knee and ulnar deviation of the fingers. Laboratory testing reveals a positive ELISA for anti-IgG antibodies. The patient is started on a first-line disease-modifying drug, but three weeks later is found to be critically leukopenic after three weeks. Which of the following medications can be used to specifically reverse the effects of the administered drug?]] |
| Answer A | AnswerA::Infliximab |
| Answer A Explanation | [[AnswerAExp::Incorrect: Infliximab is an antibody directed against TNF-alpha, indicated for use in Rheumatoid arthritis, Crohn’s disease and ankylosing spondylitis. All anti-TNF-alpha agents increase the risk of reactivation TB. While Infliximab can be used to treat Rheumatoid arthritis, it cannot rescue the toxic effects of methotrexate.]] |
| Answer B | AnswerB::Leucovorin |
| Answer B Explanation | [[AnswerBExp::Correct: Leucovorin is equivalent to activated folinic acid. It can be administered to “rescue” the effects of Methotrexate. Methotrexate competitively inhibits folic acid binding to Dihydrofolate reductase, an enzyme responsible for the conversion of dihydrofolic acid to tetrahydrofolic acid. Leucovorin administration bypasses this step in thymidine synthesis and thereby reverses the effect of methotrexate.]] |
| Answer C | AnswerC::Vitamin K |
| Answer C Explanation | [[AnswerCExp::Incorrect: Vitamin K is used to reverse the effects of Warfarin.]] |
| Answer D | AnswerD::Protamine |
| Answer D Explanation | [[AnswerDExp::Incorrect: Protamine is used to reverse the effects of heparin.]] |
| Answer E | AnswerE::Naloxone |
| Answer E Explanation | [[AnswerEExp::Incorrect: Naloxone is used to reverse the effects of morphine overdose.]] |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient in this vignette is suffering from rheumatoid arthritis (RA), an autoimmune inflammatory disease which commonly presents as systemic joint pain. A positive rheumatoid factor (anti AgG antibody) is 80% sensitive and 90% specific for RA. RA is two to three times more prevalent in females than males. Rheumatoid arthritis tend to affect the MCP and PIP joint of the hand and spares the DIP. Swelling of the MCP joint can cause the ulnar deviation of the fingers seen in this patient.
RA is treated with a combination of analgesics and disease-modifying antirheumatic drugs (DMARDs). The first-line disease modifying drug for RA is methotrexate. Methotrexate competitively inhibits folic acid binding to Dihydrofolate reductase, an enzyme responsible for the conversion of dihydrofolic acid to tetrahydrofolic acid. Leucovorin is equivalent to activated folinic acid. It can be administered to “rescue” the effects of Methotrexate. Methotrexate competitively inhibits folic acid binding to Dihydrofolate reductase, an enzyme responsible for the conversion of dihydrofolic acid to tetrahydrofolic acid. Leucovorin administration bypasses this step in thymidine synthesis and thereby reverses the effect of methotrexate. Educational Objective: Leucovorin (folinic acid) can be used to “rescue” methotrexate toxicity. References: First Aid 2012 Page 399 |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Rheumatoid arthritis, WBRKeyword::RA, WBRKeyword::Methotrexate, WBRKeyword::Chemotherapy, WBRKeyword::Side effect, WBRKeyword::Myelosuppression, WBRKeyword::Leukopenia |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |