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Center for Health Sciences
Medical Physiology - Evidence-Based Medicine
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What is EBM?

Patient Care Model
Life-long Learning
Why is EBM Important?
Available Evidence?
EBM Issues

The Well-built Question

The EBM Process
Anatomy of a Question

Finding Evidence

Selecting a Resource
Searching the Resource
Reviewing Search Results
Returning to the Patient

Evaluating Evidence

Evaluating the Validity
Validity Questions


Knowledge Test

Multiple Sclerosis
Case #2
Case #3
Case #4




In the following exercise, click an answer and a pop-up box will appear that contains feedback.

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Case 1: Multiple Sclerosis

The Patient

1. Start with the patient - a clinical problem or question arises out of the care of the patient.

A 28-year-old woman presents with diplopia and imbalance. Past medical history is remarkable for migraine without aura and an unexplained 2-week episode of right monocular visual loss at age 22. Review of systems shows that for the past 2 months, she has experienced unusual fatigue, especially in the afternoon. She denies alcohol, tobacco, and recreational or prescription drug use. A maternal first cousin has MS. Physical examination shows pale optic disks, left internuclear ophthalmoplegia, wide-based gait with inability to perform tandem gait, and a left Babinski sign.

Brain MRI shows six white matter lesions. Four are periventricular and two of them enhance after administration of intravenous gadolinium. Visual evoked potentials show right conduction slowing compatible with an optic nerve lesion. CBC, chemistry group, RPR, sTSH, and ANA are within normal limits. A diagnosis of RRMS is confirmed using 2005 Revised McDonald Criteria, having shown multifocal central neurologic lesions disseminated in space and time.

After initial diagnosis, education, and counseling about MS and various forms of therapy, the patient initiated a five-day course of intravenous methylprednisolone to attempt to speed recovery from the current exacerbation. Her diplopia and imbalance resolved within 3 weeks, and at follow-up examination the only persistent abnormalities were optic disk pallor and the left Babinski sign. The patient elected to begin therapy with parenteral ß-interferon. Fifteen months later, she reported only intermittent fatigue and had experienced no new exacerbations. Repeated brain MRI showed one new brain lesion but no evidence of gadolinium enhancement.

The patient elected to continue interferon therapy but has heard from a relative that adding modafinil, every morning may reduce diurnal fatigue. A third year medical student working with the case has decided to research this possibility and report results to the patient's physician.

The Question

2. Construct a well-built clinical question derived from the case.

Based on this scenario, choose the best, well-built clinical question:

A. For an adult female diagnosed with RRMS and undergoing interferon therapy can modafinil be taken to provide relief from daily fatigue?

B. For an adult female diagnosed with RRMS can modafinil be taken to provide relief from daily fatigue?

C. For an adult female can modafinil be taken to provide relief from daily fatigue?

The Resource

3. Launch DynaMed and conduct a search using the well-built question from Answer A above. (Hint: In point-of-care databases it is best to start by searching for the pre-dominant medical condition, in this case "multiple sclerosis.")

Based on your DynaMed search results please answer the following question.

What treatments for fatigue in MS patients are discussed by DynaMed?:

A. Just aspirin

B. Just modafinil

C. Modafinil, aspirin, and amantadine

The Evaluation

4. Appraise the evidence for its validity (closeness to the truth) and its applicability (usefulness in clinical practice).

As stated previously, evaluating medical research reports is a complex and time-consuming undertaking. The best resources in the clinical setting are the point-of-care databases which provide pre-evaluated answers to specific clinical questions in the practical time frame needed by a practicing physician.

DynaMed is a good example of a database providing patient-oriented, evidence-based clinical answers that are pre-evaluated for validity. Evidence in DynaMed is labeled in one of three levels so clinicians can quickly grasp the reliability of conclusions and recommendations.

Based on your DynaMed search results please answer the following question.

For treating fatigue in MS patients what level of evidence was assigned to aspirin therapy and modafinil therapy by DynaMed?:

A. Level 1 [likely reliable] Evidence

B. Level 2 [mid- level] Evidence

C. Level 3 [lacking direct] Evidence

We now go to the Knowledge Test: Case No. 2.