{"version":"1.0.0","segments":[{"startTime":0.0,"endTime":3.19,"body":"[intro music]"},{"startTime":3.19,"endTime":5.6,"body":"[Dr. Handy] Hi, welcome"},{"startTime":3.19,"endTime":5.6,"body":"to Harrison's Podclass"},{"startTime":5.6,"endTime":8.74,"body":"where we discuss important"},{"startTime":5.6,"endTime":8.74,"body":"concepts in internal medicine."},{"startTime":8.74,"endTime":9.89,"body":"I'm Cathy Handy."},{"startTime":9.89,"endTime":11.525,"body":"[Dr. Wiener] And I'm Charlie"},{"startTime":9.89,"endTime":11.525,"body":"Wiener and we're coming to you"},{"startTime":11.525,"endTime":14.258,"body":"from the Johns Hopkins School of Medicine."},{"startTime":15.81,"endTime":17.509,"body":"[Dr. Handy] Welcome to episode 57,"},{"startTime":17.509,"endTime":20.21,"body":"a 31-year-old with blurry vision."},{"startTime":20.21,"endTime":21.26,"body":"[Dr. Wiener] Okay Cathy,"},{"startTime":21.26,"endTime":24.35,"body":"so a 31-year-old white woman comes to you"},{"startTime":24.35,"endTime":27.45,"body":"complaining of symptoms of"},{"startTime":24.35,"endTime":27.45,"body":"blurred vision for a few months"},{"startTime":27.45,"endTime":29.072,"body":"and recent leg weakness."},{"startTime":29.072,"endTime":30.55,"body":"[Dr. Handy] What kind of weakness?"},{"startTime":30.55,"endTime":32.86,"body":"[Dr. Wiener] She feels as"},{"startTime":30.55,"endTime":32.86,"body":"though her left leg is weak,"},{"startTime":32.86,"endTime":33.95,"body":"but it's not sore,"},{"startTime":33.95,"endTime":36.45,"body":"and this has been present"},{"startTime":33.95,"endTime":36.45,"body":"for the past weeks."},{"startTime":36.45,"endTime":38.13,"body":"[Dr. Handy] Okay, so unilateral weakness"},{"startTime":38.13,"endTime":41.64,"body":"in the lower extremity with blurry vision."},{"startTime":41.64,"endTime":42.49,"body":"Tell me more."},{"startTime":42.49,"endTime":44.04,"body":"[Dr. Wiener] Okay, well,"},{"startTime":42.49,"endTime":44.04,"body":"on further questioning,"},{"startTime":44.04,"endTime":46.64,"body":"she reports that she's had"},{"startTime":44.04,"endTime":46.64,"body":"intermittent blurring of her vision"},{"startTime":46.64,"endTime":48.01,"body":"for the past two months,"},{"startTime":48.01,"endTime":49.44,"body":"although it's been more persistent"},{"startTime":49.44,"endTime":51.2,"body":"in the past two weeks."},{"startTime":51.2,"endTime":53.01,"body":"She states that she also notes that colors"},{"startTime":53.01,"endTime":54.69,"body":"seem less vivid to her"},{"startTime":54.69,"endTime":56.71,"body":"and that her symptoms are"},{"startTime":54.69,"endTime":56.71,"body":"worse in the right eye"},{"startTime":56.71,"endTime":58.01,"body":"than in the left eye."},{"startTime":58.01,"endTime":58.843,"body":"Three months ago,"},{"startTime":58.843,"endTime":62.39,"body":"she had a few episodes of"},{"startTime":58.843,"endTime":62.39,"body":"sharp pains in the right eye"},{"startTime":62.39,"endTime":64.5,"body":"that were worse when she looked around."},{"startTime":64.5,"endTime":66.33,"body":"These lasted for about two to three days,"},{"startTime":66.33,"endTime":68.3,"body":"then went away spontaneously."},{"startTime":68.3,"endTime":69.33,"body":"She thought it was eyestrain,"},{"startTime":69.33,"endTime":71.01,"body":"so she didn't seek attention."},{"startTime":71.01,"endTime":73.03,"body":"[Dr. Handy] Okay, so I'm"},{"startTime":71.01,"endTime":73.03,"body":"trying to put together"},{"startTime":73.03,"endTime":75.8,"body":"one lesion that would cause blurry vision,"},{"startTime":75.8,"endTime":79.82,"body":"unilateral eye pain, and left"},{"startTime":75.8,"endTime":79.82,"body":"lower extremity weakness."},{"startTime":79.82,"endTime":82.32,"body":"I can't think of one lesion"},{"startTime":79.82,"endTime":82.32,"body":"that would be causing this,"},{"startTime":82.32,"endTime":83.67,"body":"so now I'm starting to think"},{"startTime":83.67,"endTime":85.02,"body":"of systemic processes"},{"startTime":85.02,"endTime":87.29,"body":"that would be contributing"},{"startTime":85.02,"endTime":87.29,"body":"to these symptoms,"},{"startTime":87.29,"endTime":89.96,"body":"mostly inflammatory or infectious causes."},{"startTime":89.96,"endTime":92.17,"body":"But tell me more about"},{"startTime":89.96,"endTime":92.17,"body":"what's going on with her."},{"startTime":92.17,"endTime":93.34,"body":"[Dr. Wiener] Okay, well, as I mentioned"},{"startTime":93.34,"endTime":94.85,"body":"the pain in her right eye three months ago"},{"startTime":94.85,"endTime":96.63,"body":"subsided after a few days"},{"startTime":96.63,"endTime":99.43,"body":"and since then her vision"},{"startTime":96.63,"endTime":99.43,"body":"changes have worsened."},{"startTime":99.43,"endTime":101.01,"body":"With regards to the weakness,"},{"startTime":101.01,"endTime":103.915,"body":"she sometimes feels as if her"},{"startTime":101.01,"endTime":103.915,"body":"left leg will give out on her"},{"startTime":103.915,"endTime":106.32,"body":"if she stands on it for a"},{"startTime":103.915,"endTime":106.32,"body":"prolonged period of time,"},{"startTime":106.32,"endTime":108.11,"body":"there is no soreness, there's no redness"},{"startTime":108.11,"endTime":109.48,"body":"and there's no pain."},{"startTime":109.48,"endTime":110.38,"body":"And she really has trouble"},{"startTime":110.38,"endTime":112.44,"body":"telling me more symptoms than that."},{"startTime":112.44,"endTime":113.841,"body":"[Dr. Handy] What about"},{"startTime":112.44,"endTime":113.841,"body":"our past medical history"},{"startTime":113.841,"endTime":116.56,"body":"and her physical examination?"},{"startTime":116.56,"endTime":117.71,"body":"[Dr. Wiener] So her past medical history"},{"startTime":117.71,"endTime":119.885,"body":"is significant for"},{"startTime":117.71,"endTime":119.885,"body":"type 1 diabetes mellitus"},{"startTime":119.885,"endTime":121.8,"body":"for which she uses an insulin pump,"},{"startTime":121.8,"endTime":126.21,"body":"her hemoglobin A1c is"},{"startTime":121.8,"endTime":126.21,"body":"consistently around 5.5%."},{"startTime":126.21,"endTime":127.85,"body":"Despite your best guidance,"},{"startTime":127.85,"endTime":129.87,"body":"she has smoked one pack"},{"startTime":127.85,"endTime":129.87,"body":"of cigarettes daily"},{"startTime":129.87,"endTime":131.43,"body":"since the age of 18."},{"startTime":131.43,"endTime":132.56,"body":"On physical examination,"},{"startTime":132.56,"endTime":134.43,"body":"she's fully alert and fully oriented"},{"startTime":134.43,"endTime":136.287,"body":"with no cognitive issues."},{"startTime":136.287,"endTime":137.77,"body":"However, there's spasticity"},{"startTime":137.77,"endTime":140.87,"body":"in both of her lower"},{"startTime":137.77,"endTime":140.87,"body":"extremities with passive motion."},{"startTime":140.87,"endTime":144.02,"body":"Deep tendon reflexes are 3+ bilaterally"},{"startTime":144.02,"endTime":147.31,"body":"and strength in the"},{"startTime":144.02,"endTime":147.31,"body":"quadriceps on her left side"},{"startTime":147.31,"endTime":151.0,"body":"is markedly diminished at"},{"startTime":147.31,"endTime":151.0,"body":"three to four, over five."},{"startTime":151.0,"endTime":152.91,"body":"All of the strength in"},{"startTime":151.0,"endTime":152.91,"body":"the lower extremities"},{"startTime":152.91,"endTime":156.102,"body":"is normal bilaterally and"},{"startTime":152.91,"endTime":156.102,"body":"is otherwise symmetric."},{"startTime":156.102,"endTime":158.02,"body":"[Dr. Handy] So a note"},{"startTime":156.102,"endTime":158.02,"body":"about that neuro exam,"},{"startTime":158.02,"endTime":161.13,"body":"the unilateral weakness with hyperreflexia"},{"startTime":161.13,"endTime":163.963,"body":"and spasticity that you"},{"startTime":161.13,"endTime":163.963,"body":"described in the lower extremity"},{"startTime":163.963,"endTime":166.73,"body":"is consistent with an"},{"startTime":163.963,"endTime":166.73,"body":"upper motor neuron lesion."},{"startTime":166.73,"endTime":169.72,"body":"What about the rest of her"},{"startTime":166.73,"endTime":169.72,"body":"neurologic examination?"},{"startTime":169.72,"endTime":170.61,"body":"[Dr. Wiener] Okay, well,"},{"startTime":170.61,"endTime":172.77,"body":"her sensation to light touch and pinprick"},{"startTime":172.77,"endTime":174.8,"body":"is decreased on the lower extremities"},{"startTime":174.8,"endTime":176.29,"body":"and you're able to perform"},{"startTime":176.29,"endTime":178.55,"body":"a dilated funduscopic examination,"},{"startTime":178.55,"endTime":181.24,"body":"which shows swelling of her optic disc."},{"startTime":181.24,"endTime":182.6,"body":"Her cardiac, pulmonary"},{"startTime":182.6,"endTime":184.81,"body":"and abdominal examinations are normal,"},{"startTime":184.81,"endTime":186.94,"body":"and she has no skin rashes."},{"startTime":186.94,"endTime":189.95,"body":"I didn't mention it earlier but"},{"startTime":186.94,"endTime":189.95,"body":"her vital signs were normal."},{"startTime":189.95,"endTime":192.0,"body":"[Dr. Handy] So based"},{"startTime":189.95,"endTime":192.0,"body":"on this physical exam,"},{"startTime":192.0,"endTime":194.41,"body":"along with what sounds like optic neuritis"},{"startTime":194.41,"endTime":196.11,"body":"with diminished visual acuity,"},{"startTime":196.11,"endTime":199.01,"body":"periorbital pain, that's"},{"startTime":196.11,"endTime":199.01,"body":"aggravated by eye movement"},{"startTime":199.01,"endTime":200.95,"body":"that preceded the visual loss"},{"startTime":200.95,"endTime":202.28,"body":"and weakness of the limbs"},{"startTime":202.28,"endTime":204.31,"body":"that is of the upper motor neuron type,"},{"startTime":204.31,"endTime":206.43,"body":"I'm actually leaning"},{"startTime":204.31,"endTime":206.43,"body":"towards multiple sclerosis"},{"startTime":206.43,"endTime":209.73,"body":"as the cause of the symptoms"},{"startTime":206.43,"endTime":209.73,"body":"in this 31-year-old woman."},{"startTime":209.73,"endTime":211.39,"body":"She has controlled her glucoses"},{"startTime":211.39,"endTime":213.56,"body":"with an impressive A1c of 5.5,"},{"startTime":213.56,"endTime":216.37,"body":"so I doubt she has significant"},{"startTime":213.56,"endTime":216.37,"body":"peripheral neuropathy"},{"startTime":216.37,"endTime":217.36,"body":"but that would not explain"},{"startTime":217.36,"endTime":219.61,"body":"the other physical exam findings anyways."},{"startTime":219.61,"endTime":221.95,"body":"[Dr. Wiener] Okay, so the question asks,"},{"startTime":221.95,"endTime":224.46,"body":"based on the history and"},{"startTime":221.95,"endTime":224.46,"body":"physical examination,"},{"startTime":224.46,"endTime":225.96,"body":"which of the following findings"},{"startTime":225.96,"endTime":230.183,"body":"is most likely to be demonstrated"},{"startTime":225.96,"endTime":230.183,"body":"on further evaluation?"},{"startTime":230.183,"endTime":233.8,"body":"Option A is an elevated"},{"startTime":230.183,"endTime":233.8,"body":"protein levels in the CSF"},{"startTime":233.8,"endTime":236.85,"body":"to more than 100 mg/dL."},{"startTime":236.85,"endTime":241.838,"body":"Option B is hyperintensity"},{"startTime":236.85,"endTime":241.838,"body":"on a T1-weighted MRI image"},{"startTime":241.838,"endTime":245.05,"body":"consistent with a mass"},{"startTime":241.838,"endTime":245.05,"body":"lesion in the occipital lobe"},{"startTime":245.05,"endTime":247.78,"body":"and surrounding hydrocephalus."},{"startTime":247.78,"endTime":252.68,"body":"Option C is hyperintensity"},{"startTime":247.78,"endTime":252.68,"body":"on a T2-weighted MRI image"},{"startTime":252.68,"endTime":254.45,"body":"in multiple areas of the brain,"},{"startTime":254.45,"endTime":256.87,"body":"brainstem and spinal cord."},{"startTime":256.87,"endTime":259.69,"body":"Option D is marked"},{"startTime":256.87,"endTime":259.69,"body":"increase in transmission"},{"startTime":259.69,"endTime":263.109,"body":"of somatosensory evoked"},{"startTime":259.69,"endTime":263.109,"body":"potentials of the lower limbs."},{"startTime":263.109,"endTime":265.8,"body":"Option E is presence of 15 polys"},{"startTime":265.8,"endTime":267.8,"body":"in the cerebral spinal fluid."},{"startTime":267.8,"endTime":268.71,"body":"[Dr. Handy] Well as I mentioned,"},{"startTime":268.71,"endTime":271.2,"body":"I think this is multiple sclerosis or MS,"},{"startTime":271.2,"endTime":272.83,"body":"so the answer is C,"},{"startTime":272.83,"endTime":274.77,"body":"you would expect to see hyperintensity"},{"startTime":274.77,"endTime":276.71,"body":"on T2-weighted MRI images"},{"startTime":276.71,"endTime":280.34,"body":"in multiple areas of the brain,"},{"startTime":276.71,"endTime":280.34,"body":"brainstem and spinal cord."},{"startTime":280.34,"endTime":281.75,"body":"[Dr. Wiener] Okay, well,"},{"startTime":280.34,"endTime":281.75,"body":"tell me more about MS"},{"startTime":281.75,"endTime":283.43,"body":"and how you came to that conclusion."},{"startTime":283.43,"endTime":285.74,"body":"[Dr. Handy] It's an autoimmune"},{"startTime":283.43,"endTime":285.74,"body":"demyelinating disorder"},{"startTime":285.74,"endTime":286.99,"body":"of the central nervous system"},{"startTime":286.99,"endTime":288.88,"body":"which can present in many ways."},{"startTime":288.88,"endTime":291.36,"body":"It can present with an"},{"startTime":288.88,"endTime":291.36,"body":"abrupt onset of symptoms,"},{"startTime":291.36,"endTime":293.84,"body":"or it can also develop gradually."},{"startTime":293.84,"endTime":295.85,"body":"The most common initial"},{"startTime":293.84,"endTime":295.85,"body":"presenting symptoms"},{"startTime":295.85,"endTime":297.97,"body":"include sensory loss, optic neuritis,"},{"startTime":297.97,"endTime":300.53,"body":"weakness, paresthesias and diplopia."},{"startTime":300.53,"endTime":303.34,"body":"She had a few of these,"},{"startTime":300.53,"endTime":303.34,"body":"as you mentioned before."},{"startTime":303.34,"endTime":305.33,"body":"Weakness of the limbs may be asymmetric"},{"startTime":305.33,"endTime":307.16,"body":"and manifest as loss of strength,"},{"startTime":307.16,"endTime":309.47,"body":"speed, dexterity or endurance."},{"startTime":309.47,"endTime":311.85,"body":"Symptoms are upper motor neuron in origin"},{"startTime":311.85,"endTime":315.03,"body":"and have associated"},{"startTime":311.85,"endTime":315.03,"body":"spasticity, hyperreflexia"},{"startTime":315.03,"endTime":317.28,"body":"and Babinski sign most commonly."},{"startTime":317.28,"endTime":319.23,"body":"However if there's a spinal cord lesion,"},{"startTime":319.23,"endTime":320.84,"body":"lower motor neuron signs"},{"startTime":320.84,"endTime":323.67,"body":"and loss of reflexes may also be seen."},{"startTime":323.67,"endTime":324.93,"body":"A diagnosis of MS"},{"startTime":324.93,"endTime":327.7,"body":"can be difficult to confirm"},{"startTime":324.93,"endTime":327.7,"body":"in some individuals,"},{"startTime":327.7,"endTime":330.16,"body":"there is no definitive test for MS,"},{"startTime":330.16,"endTime":332.13,"body":"but the diagnostic criteria require"},{"startTime":332.13,"endTime":333.9,"body":"two or more episodes of symptoms"},{"startTime":333.9,"endTime":335.9,"body":"and two or more signs of dysfunction"},{"startTime":335.9,"endTime":338.33,"body":"in non-contiguous white matter tracts."},{"startTime":338.33,"endTime":340.66,"body":"[Dr. Wiener] So this patient"},{"startTime":338.33,"endTime":340.66,"body":"seems to meet that criteria."},{"startTime":340.66,"endTime":342.45,"body":"[Dr. Handy] Yes, she"},{"startTime":340.66,"endTime":342.45,"body":"had the optic neuritis"},{"startTime":342.45,"endTime":343.45,"body":"about three months ago"},{"startTime":343.45,"endTime":345.67,"body":"and then the more recent leg weakness."},{"startTime":345.67,"endTime":347.19,"body":"[Dr. Wiener] What other"},{"startTime":345.67,"endTime":347.19,"body":"diagnostic findings"},{"startTime":347.19,"endTime":348.67,"body":"can help make this diagnosis?"},{"startTime":348.67,"endTime":350.48,"body":"You mentioned the MRI findings."},{"startTime":350.48,"endTime":352.46,"body":"[Dr. Handy] MRI can help"},{"startTime":350.48,"endTime":352.46,"body":"confirm the diagnosis"},{"startTime":352.46,"endTime":355.453,"body":"in patients with diagnostic"},{"startTime":352.46,"endTime":355.453,"body":"clinical findings."},{"startTime":355.453,"endTime":357.31,"body":"MRI characteristically shows"},{"startTime":357.31,"endTime":359.84,"body":"multiple hyperintense T2-weighted lesions"},{"startTime":359.84,"endTime":361.44,"body":"that can be present in the brain,"},{"startTime":361.44,"endTime":363.6,"body":"brainstem and the spinal cord."},{"startTime":363.6,"endTime":366.64,"body":"More than 90% of lesions that"},{"startTime":363.6,"endTime":366.64,"body":"are seen on MRI, however,"},{"startTime":366.64,"endTime":368.31,"body":"are asymptomatic."},{"startTime":368.31,"endTime":369.99,"body":"Approximately one third of lesions"},{"startTime":369.99,"endTime":372.63,"body":"that appear hyperintense"},{"startTime":369.99,"endTime":372.63,"body":"on T2-weighted images"},{"startTime":372.63,"endTime":375.72,"body":"will be hypointense on T1-weighted images."},{"startTime":375.72,"endTime":377.62,"body":"These \"black holes\""},{"startTime":377.62,"endTime":381.74,"body":"may be a marker of irreversible"},{"startTime":377.62,"endTime":381.74,"body":"demyelinated axonal loss."},{"startTime":381.74,"endTime":383.24,"body":"[Dr. Wiener] What about the other choices?"},{"startTime":383.24,"endTime":386.56,"body":"CSF was mentioned and"},{"startTime":383.24,"endTime":386.56,"body":"also evoked potentials?"},{"startTime":386.56,"endTime":388.1,"body":"[Dr. Handy] Evoked"},{"startTime":386.56,"endTime":388.1,"body":"potentials are no longer"},{"startTime":388.1,"endTime":389.43,"body":"commonly used in MS"},{"startTime":389.43,"endTime":391.41,"body":"and are most useful in studying pathways"},{"startTime":391.41,"endTime":394.225,"body":"that are not exhibiting clinical symptoms."},{"startTime":394.225,"endTime":396.774,"body":"Evoked potentials are not specific to MS"},{"startTime":396.774,"endTime":399.3,"body":"although a marked delay in"},{"startTime":396.774,"endTime":399.3,"body":"latency of transmissions"},{"startTime":399.3,"endTime":401.1,"body":"does suggest demyelination."},{"startTime":401.1,"endTime":402.22,"body":"In patients with MS,"},{"startTime":402.22,"endTime":405.42,"body":"the CSF may show an increased"},{"startTime":402.22,"endTime":405.42,"body":"number of mononuclear cells,"},{"startTime":405.42,"endTime":408.26,"body":"although CSF protein is typically normal."},{"startTime":408.26,"endTime":410.15,"body":"Oligoclonal bands help to assess"},{"startTime":410.15,"endTime":414.252,"body":"the intrathecal production"},{"startTime":410.15,"endTime":414.252,"body":"of immunoglobulin for IgG."},{"startTime":414.252,"endTime":416.76,"body":"The presence of two or more"},{"startTime":414.252,"endTime":416.76,"body":"discrete oligoclonal bands"},{"startTime":416.76,"endTime":419.03,"body":"in the CSF that are not"},{"startTime":416.76,"endTime":419.03,"body":"present in the serum"},{"startTime":419.03,"endTime":422.34,"body":"is found in more than 75% of MS patients."},{"startTime":422.34,"endTime":427.04,"body":"If a patient in the CSF has a"},{"startTime":422.34,"endTime":427.04,"body":"pleocytosis of over 75 cells,"},{"startTime":427.04,"endTime":430.11,"body":"presence of any polys"},{"startTime":427.04,"endTime":430.11,"body":"or protein concentration"},{"startTime":430.11,"endTime":434.398,"body":"over a 100 mg/dL, again,"},{"startTime":430.11,"endTime":434.398,"body":"this is all within the CSF,"},{"startTime":434.398,"endTime":436.56,"body":"an alternative diagnosis should be sought"},{"startTime":436.56,"endTime":439.08,"body":"because MS is not the most likely cause."},{"startTime":439.08,"endTime":440.37,"body":"[Dr. Wiener] So any other"},{"startTime":439.08,"endTime":440.37,"body":"tests you would order"},{"startTime":440.37,"endTime":443.03,"body":"to rule out other potential possibilities?"},{"startTime":443.03,"endTime":444.346,"body":"[Dr. Handy] Well, disorders possibly"},{"startTime":444.346,"endTime":447.66,"body":"mistaken for MS would"},{"startTime":444.346,"endTime":447.66,"body":"include neuromyelitis optica,"},{"startTime":447.66,"endTime":450.06,"body":"sarcoidosis, vascular disorders,"},{"startTime":450.06,"endTime":453.14,"body":"like antiphospholipid"},{"startTime":450.06,"endTime":453.14,"body":"syndrome and vasculitis,"},{"startTime":453.14,"endTime":454.72,"body":"rarely a CNS lymphoma"},{"startTime":454.72,"endTime":456.62,"body":"and still more rarely infections,"},{"startTime":456.62,"endTime":458.68,"body":"such as syphilis or Lyme disease."},{"startTime":458.68,"endTime":460.15,"body":"But the specific tests required"},{"startTime":460.15,"endTime":462.08,"body":"to exclude alternative diagnosis"},{"startTime":462.08,"endTime":464.48,"body":"will vary with each clinical situation."},{"startTime":464.48,"endTime":468.11,"body":"However, an erythrocyte"},{"startTime":464.48,"endTime":468.11,"body":"sedimentation rate, or ESR level,"},{"startTime":468.11,"endTime":471.14,"body":"serum B12 level, anti-nuclear antibodies"},{"startTime":471.14,"endTime":473.86,"body":"and a Treponema antibody"},{"startTime":471.14,"endTime":473.86,"body":"should probably be obtained"},{"startTime":473.86,"endTime":476.33,"body":"in all patients with suspected MS."},{"startTime":476.33,"endTime":479.67,"body":"[Dr. Wiener] Okay, well, so"},{"startTime":476.33,"endTime":479.67,"body":"this is a two part question."},{"startTime":479.67,"endTime":482.432,"body":"And the second part of the question asks,"},{"startTime":482.432,"endTime":483.625,"body":"in this patient,"},{"startTime":483.625,"endTime":486.053,"body":"the expected finding is"},{"startTime":483.625,"endTime":486.053,"body":"demonstrated on testing,"},{"startTime":486.053,"endTime":488.73,"body":"and we'll assume that's"},{"startTime":486.053,"endTime":488.73,"body":"the MRI that you mentioned,"},{"startTime":488.73,"endTime":490.05,"body":"on further historical review,"},{"startTime":490.05,"endTime":491.32,"body":"the patient reports that she had"},{"startTime":491.32,"endTime":492.89,"body":"one prior episode of blurred vision"},{"startTime":492.89,"endTime":494.59,"body":"that resolved spontaneously"},{"startTime":494.59,"endTime":496.16,"body":"about eight months ago."},{"startTime":496.16,"endTime":497.87,"body":"She never sought treatment for it,"},{"startTime":497.87,"endTime":500.17,"body":"although it did last for two weeks."},{"startTime":500.17,"endTime":502.83,"body":"You make the correct diagnosis of MS."},{"startTime":502.83,"endTime":505.74,"body":"All of the following are"},{"startTime":502.83,"endTime":505.74,"body":"epidemiologic risk factors"},{"startTime":505.74,"endTime":508.81,"body":"for multiple sclerosis, except?"},{"startTime":508.81,"endTime":512.545,"body":"Option A is age between 20 and 40;"},{"startTime":512.545,"endTime":515.43,"body":"B. cigarette smoking;"},{"startTime":515.43,"endTime":518.07,"body":"C. female sex;"},{"startTime":518.07,"endTime":520.19,"body":"D. history of an autoimmune disorder,"},{"startTime":520.19,"endTime":522.97,"body":"such as type 1 diabetes in this case;"},{"startTime":522.97,"endTime":525.09,"body":"or E. white race."},{"startTime":525.09,"endTime":526.3,"body":"[Dr. Handy] So the question is asking"},{"startTime":526.3,"endTime":528.74,"body":"about the epidemiology"},{"startTime":526.3,"endTime":528.74,"body":"of multiple sclerosis,"},{"startTime":528.74,"endTime":530.22,"body":"so let's go through that."},{"startTime":530.22,"endTime":534.203,"body":"It affects about 350,000"},{"startTime":530.22,"endTime":534.203,"body":"individuals in the United States"},{"startTime":534.203,"endTime":535.97,"body":"and has a variable clinical course"},{"startTime":535.97,"endTime":539.39,"body":"with some individuals"},{"startTime":535.97,"endTime":539.39,"body":"experiencing very limited symptoms"},{"startTime":539.39,"endTime":542.98,"body":"and others becoming very"},{"startTime":539.39,"endTime":542.98,"body":"incapacitated due to the disease."},{"startTime":542.98,"endTime":546.15,"body":"MS is three times more"},{"startTime":542.98,"endTime":546.15,"body":"common in women than men"},{"startTime":546.15,"endTime":549.76,"body":"and the typical age of onset"},{"startTime":546.15,"endTime":549.76,"body":"is between 20 and 40 years."},{"startTime":549.76,"endTime":552.51,"body":"So she's right in the"},{"startTime":549.76,"endTime":552.51,"body":"middle of that age range."},{"startTime":552.51,"endTime":554.68,"body":"MS is more common in white individuals"},{"startTime":554.68,"endTime":556.92,"body":"than those of African or Asian descent."},{"startTime":556.92,"endTime":559.11,"body":"In addition, geographic variations"},{"startTime":559.11,"endTime":561.75,"body":"in disease prevalence have"},{"startTime":559.11,"endTime":561.75,"body":"also been demonstrated,"},{"startTime":561.75,"endTime":564.02,"body":"with higher prevalence in"},{"startTime":561.75,"endTime":564.02,"body":"the temperate zone areas"},{"startTime":564.02,"endTime":566.38,"body":"of Northern North America"},{"startTime":564.02,"endTime":566.38,"body":"and Northern Europe,"},{"startTime":566.38,"endTime":568.83,"body":"Southern Australia and New Zealand."},{"startTime":568.83,"endTime":571.18,"body":"In contrast, the tropics have a prevalence"},{"startTime":571.18,"endTime":573.73,"body":"that is 10 to 20 times less."},{"startTime":573.73,"endTime":575.35,"body":"Other well-established risk factors"},{"startTime":575.35,"endTime":578.46,"body":"for the development of MS"},{"startTime":575.35,"endTime":578.46,"body":"include vitamin D deficiency,"},{"startTime":578.46,"endTime":580.33,"body":"exposure to Epstein-Barr Virus"},{"startTime":580.33,"endTime":583.49,"body":"after early childhood"},{"startTime":580.33,"endTime":583.49,"body":"and cigarette smoking."},{"startTime":583.49,"endTime":585.88,"body":"Now, despite the fact that"},{"startTime":583.49,"endTime":585.88,"body":"this is an autoimmune disorder"},{"startTime":585.88,"endTime":587.81,"body":"there actually has not been an association"},{"startTime":587.81,"endTime":590.6,"body":"between MS and other autoimmune disorders."},{"startTime":590.6,"endTime":592.8,"body":"[Dr. Wiener] So in this"},{"startTime":590.6,"endTime":592.8,"body":"case, the type 1 diabetes"},{"startTime":592.8,"endTime":595.51,"body":"is the one that is not"},{"startTime":592.8,"endTime":595.51,"body":"related to her situation."},{"startTime":595.51,"endTime":596.5,"body":"[Dr. Handy] That's correct."},{"startTime":596.5,"endTime":597.64,"body":"[Dr. Wiener] Okay, great."},{"startTime":597.64,"endTime":599.18,"body":"So the teaching point in this case"},{"startTime":599.18,"endTime":600.51,"body":"is that multiple sclerosis"},{"startTime":600.51,"endTime":602.81,"body":"is largely still a clinical diagnosis"},{"startTime":602.81,"endTime":604.93,"body":"involving multiple"},{"startTime":602.81,"endTime":604.93,"body":"neurologic abnormalities"},{"startTime":604.93,"endTime":606.4,"body":"spread over time."},{"startTime":606.4,"endTime":608.14,"body":"There are characteristic findings on MRI"},{"startTime":608.14,"endTime":610.26,"body":"that can support the diagnosis."},{"startTime":610.26,"endTime":612.11,"body":"While it is an autoimmune disease,"},{"startTime":612.11,"endTime":615.54,"body":"it is not associated with"},{"startTime":612.11,"endTime":615.54,"body":"other diseases of autoimmunity."},{"startTime":615.54,"endTime":616.373,"body":"[Dr. Handy] And to learn more,"},{"startTime":616.373,"endTime":619.276,"body":"you can read in Harrison's"},{"startTime":616.373,"endTime":619.276,"body":"chapter on multiple sclerosis."},{"startTime":619.276,"endTime":621.859,"body":"[outro music]"},{"startTime":623.8,"endTime":626.67,"body":"[Mr. Shanahan] This is Jim"},{"startTime":623.8,"endTime":626.67,"body":"Shanahan, publisher at McGraw Hill."},{"startTime":626.67,"endTime":628.3,"body":"Harrison's Podclass is brought to you"},{"startTime":628.3,"endTime":630.28,"body":"by McGraw Hill's Access Medicine,"},{"startTime":630.28,"endTime":631.78,"body":"the online medical resource"},{"startTime":631.78,"endTime":633.75,"body":"that delivers the latest trusted content"},{"startTime":633.75,"endTime":635.6,"body":"from the best minds in medicine."},{"startTime":635.6,"endTime":638.163,"body":"Go to accessmedicine.com to learn more."}]}