Updated: 2/17/2019

Marfan Syndrome

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Snapshot
  • A 32-year-old man presents to the emergency room for sudden onset of severe chest pain that radiates down his back. Physical exam reveals a tall and thin habitus, arachnodactyly, and pectus excavatum. Radiography shows widened mediastinum, concerning for an aortic dissection.
Overview
Introduction
  • Clinical definition
    • inherited connective tissue disorder characterized by aortic abnormalities and musculoskeletal deformities
  • Epidemiology
    • demographics
      • clinical manifestations typically occur in adulthood
  • Pathogenesis
    • fibrillins form a major part of connective tissues and provide structural support and elasticity to blood vessels, skin, and bones
    • abnormalities in fibrillin can result in
      • aortic abnormalities (cystic medial necrosis)
      • ectopic lens (structural weakness in ligaments of the lens)
      • skeletal deformities
  • Genetics
    • inheritance pattern
      • autosomal dominant
    • mutations
      • FBN1 gene is on chromosome 15 and encodes fibrillin-1, a glycoprotein that forms a protective sheath around elastin
        • elastin is found in multiple parts of the body, including large arteries, skin, lungs, and ligaments
  • Prognosis
    • survival has improved with better management of aortic disease
    • with early diagnosis and management, patients often have a normal life expectancy
Presentation
  • Symptoms
    • aortic dilation, aneurysm, or dissection
      • dissection will present as acute severe retrosternal chest pain radiating to the back
    • pneumothorax
  • Physical exam
    • skeletal 
      • tall and thin stature
      • long extremities
        • arm span exceeds height
      • long fingers and toes (arachnodactyly)
        • thumbnail protrudes beyond ulnar border of hand when crossed (thumb sign)
        • thumb and little finger can encircle wrist (wrist sign)
      • pectus carinatum or excavatum
      • scoliosis
      • hypermobile joints
    • ocular
      • subluxation of lenses (superior and temporal)
    • cardiovascular
      • mitral valve prolapse
        • mid-systolic click followed by a late systolic murmur
      • aortic regurgitation
        • diastolic murmur
      • mitral regurgitation
        • high-pitched holosystolic murmur
Imaging
  • Transthoracic echocardiography
    • indication
      • for all patients to evaluate for cardiac involvement
    • findings
      • mitral or aortic valve abnormalities
      • aortic aneurysm or dissection
Studies
  • Making the diagnosis
    • based on clinical presentation
    • genetic testing is not always necessary but is diagnostic
Differential
  • Homocystinuria
    • distinguishing factor
      • lens subluxation is downwards
      • mental retardation
  • Ehlers-Danlos syndrome 
    • distinguishing factor
      • hyperextensible skin and easy bruising
      • middle-sized artery aneurysms > aortic aneurysms
Treatment
  • Management approach
    • no curative treatment exists, so treatment is targeted at symptoms
  • Conservative
    • avoid high-impact contact sports
      • indication
        • for all patients
  • Medical
    • β-blockers or angiotensin receptor blockers
      • indications
        • to halt the progression of aortic root dilation
  • Operative
    • aortic aneurysm repair
      • indication
        • patients with aneurysms ≥ 4-4.5 cm
    • cardiac valve repair
      • indications
        • patients with severe mitral or aortic valve disease
Complications
  • Aortic dissection
    • most common cause of death
  • Mitral valve prolapse
  • Congestive heart failure from cardiac valve abnormalities
 

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Questions (3)
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
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(M2.OR.4798) A 28-year-old male presents to the emergency department with chest pain. He reports that one hour ago he was climbing the stairs in his home when he suddenly developed excruciating chest pain. He describes the pain as ripping and radiating to the back. The patient’s past medical history is significant for a heart murmur that is being followed by his outpatient cardiologist. He takes no medications. The patient works as a carpenter and reports being monogamous with his wife. He denies any history of intravenous drug use or recent travel. In the emergency department, the patient’s temperature is 99.4°F (37.4°C), blood pressure is 94/56 mmHg, pulse is 121/min, and respirations are 14/min. On physical exam, the patient appears to be in moderate distress and is clutching his chest. He is tall and has joint hypermobility. His breath sounds are equal and full bilaterally and has weak distal pulses.

Which of the following is most likely to be found in this patient?
Review Topic | Tested Concept

QID: 109230
1

Holosystolic, high-pitched blowing murmur at the lower left sternal border

5%

(1/21)

2

Late systolic crescendo murmur at the apex with mid-systolic click

19%

(4/21)

3

Mid-diastolic murmur at the apex with opening snap

0%

(0/21)

4

Mid-diastolic murmur at the left lower sternal border

33%

(7/21)

5

Systolic ejection murmur at the right second intercostal space

43%

(9/21)

M2 D

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(M2.OR.4774) A 36-year-old male is brought to the emergency department by fire and rescue after being found down in his apartment by his wife. His wife reports that the patient had been complaining of chest pain for the last few hours but refused to go to the hospital. She went to the grocery store for about half an hour and found her husband unresponsive on the ground when she returned home. The patient’s wife reports that his past medical history is significant for a “heart murmur” and that the patient’s father died at age 32 for unknown reasons. In the trauma bay, the patient’s temperature is 98.8°F (37.1°C), blood pressure is 88/41 mmHg, pulse is 116/min, and respirations are 12/min. On physical exam, the patient has a Glascow Coma Score (GCS) of 7. He has a tall stature with long limbs and long, slender fingers. He is also noted to have a pectus deformity. On cardiac exam, the patient has a diastolic decrescendo murmur at the left third intercostal space. He has weak brachial and femoral pulses.

Which of the following is the most likely etiology of this patient’s presentation?
Review Topic | Tested Concept

QID: 109120
1

Coronary atherosclerosis

0%

(0/70)

2

Hypertrophic cardiomyopathy

1%

(1/70)

3

Spontaneous rupture of the aorta

50%

(35/70)

4

Spontaneous rupture of the mitral chordae tendinae

9%

(6/70)

5

Spontaneous separation in the arterial wall

37%

(26/70)

M2 D

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