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Snapshot
  • A 33-year-old woman presents to the emergency department for severe eye pain with movement and vision loss in the left eye. Her symptoms began earlier in the morning and she cannot identify a cause. Physical examination is notable for a relative afferent pupillary defect noted on the swinging light test. She is scheduled for a gadolinium-enhanced MRI of the orbit and the globe; she is started on intravenous methylprednisolone.
Introduction
  • Definition
    • an inflammatory demyelinating process affecting the optic nerve
  • Epidemiology
    • incidence
      • most commonly affects women between the ages of 20-40
  • Etiology
    • multiple sclerosis
    • ethambutol
      • discontinue if findings 
    • ischemic optic neuropathy (e.g., diabetes mellitus or giant cell arteritis)
      • considered in the elerly
    • infectious and postinfectious causes
      • considered in young children
    • sarcoid-associated optic neuropathy
    • lupus-associated optic neuropathy
    • Lyme disease
    • syphilis
    • varicella
  • Pathogenesis
    • inflammatory demyelination of the optic nerve
      • there is perivascular cuffing, myelinating nerve sheath swelling, and myelin breakdown
      • believed to be immune mediated
  • Prognosis
    • many patients may have residual visual deficits
Presentation
  • Symptoms
    • typically monocular but can occur in both eyes
    • vision loss
      • typically occurs over the course of hours to days
      • most patients have a decrease in central visual acuity
        • visual acuity decreases have different ranges
    • periocular pain
      • often worsens with movement
  • Physical exam
    • decreased visual acuity, color sensitivity, and contrast sensitivity
    • fundoscopy
      • optic disc pallor and/or optic disc swelling
    • relative afferent pupillary defect
      • detected by the swinging light test
      • in the affected eye, the pupil will dilate with direct illumination after illuminating the normal eye
Imaging
  • Gadolinium-enhanced MRI of the orbit and brain
    • indication
      • when there is clinical suspicion for multiple sclerosis
Studies
  • Dependent on clinical suspicion
    • e.g., antinuclear antibody (ANA) if an autoimmune process is suspected
Treatment
  • Medical
    • high-dose IV corticosteroids
      • indication
        • can hasten visual recovery
Complications
  • Optic nerve atrophy
  • Poor visual recovery

 

 

 

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Questions (1)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
Calculator

(M2.OP.10) A 57-year-old woman presents with a cough, hemoptysis, fever, chills, and weight loss that has persisted since she returned from her trip to Thailand. She admits to having sexual contact with several prostitutes. The patient is generally healthy and is not taking any medications. She has a family history of glaucoma, diabetes mellitus, factor V Leiden, and an ischemic stroke. Her temperature is 101°F (38.3°C), blood pressure is 125/84 mmHg, pulse is 99/min, respirations are 19/min, and oxygen saturation is 95% on room air. Physical exam is notable only for some coarse breath sounds. A chest radiograph is performed as seen in Figure A. Treatment for this patient's condition is started. The patient returns to clinic with decreased visual acuity mainly in her right eye. She also reports pain in both eyes with movement. On physical examination, when a penlight is shined into the right eye, there is no pupillary constriction in either eye. The rest of her neurological exam is unremarkable. Which of the following is the most appropriate next step in management? Review Topic

QID: 105376
FIGURES:
1

Change antibiotic therapy

9%

(3/34)

2

CT head

53%

(18/34)

3

MRI head

6%

(2/34)

4

Timolol eye drops

6%

(2/34)

5

Ultrasound eye

21%

(7/34)

M2

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