Updated: 6/3/2019

Pulmonary Embolism

Topic
Review Topic
0
0
Questions
11
0
0
Evidence
10
0
0
Snapshot
  • A 36-year-old woman presents to the emergency department with worsening shortness of breath and pleuritic chest pain. Her symptoms began earlier in the day while she was waiting for her bus to return home. She recently returned from China to the United States for a business meeting. She denies any sick contacts and has not had these symptoms in the past. Medical history is unremarkable. She takes an oral contraceptive and a daily multivitamin. Her temperature is 98.6°F (37°C), blood pressure is 135/82 mmHg, pulse is 112/min, respirations are 24/min, and oxygen saturation is 89% on room air. A CT angiogram performedmed and demonstrates a filling defect in the pulmonary vasculature. She is immediately started on supplemental oxygen and heparin.
Introduction
  • Definition
    • mechanical obstruction of the pulmonary vascular secondary to a blood clot
      • typically the blood clot is a thromboembolism from a deep vein thrombosis (DVT)
  • Epidemiology
    • risk factors
      • prolonged immobilization (e.g., long travel)
      • malignancy
      • thrombophilia
      • pregnancy
      • hormonal contraceptives
  • Etiology
    • DVT (most common) 
    • septic embolism from right-heart endocarditis
    • fat embolism
    • amniotic fluid embolism
  • Pathophysiology
    • occlusion of the pulmonary vasculature results in hypoxemia and subsequent pulmonary vasoconstriction
      • the increased pulmonary constriction causes an increase in pulmonary vascular resistance, which decreases right ventricular stroke volume leading to
        • increased ventricular oxygen demand
        • right ventricular dilatation
        • decreased left ventricular preload (leading to circulatory failure)
        • poor blood flow to the lung, leading to a ventilation-perfusion mismatch
  • Prognosis
    • significantly high mortality without treatment
Presentation
  • Symptoms
    • dysnea (most common)
    • pleuritic chest pain
    • cough
    • hemoptysis
    • syncope in cases of a large pulmonary embolism (PE)
  • Physical exam
    • tachypnea
    • tachycardia
    • loud P2
    • hemodynamic instability in cases of a large PE
Imaging
  • CT angiography of the chest 
    • indication
      • imaging study of choice in the diagnostic evaluation of PE
        • sensitivity of ~90%
        • specificity of ~95%
    • comments
      • chest radiography is typically normal or it may show 
        • pleural effusions 
        • Hampton hump (wedged-shaped infarct)
        • Westermark sign (avascularity distal to the PE)
  • V/Q scan 
    • indication
      • performed if the pre-test probability of PE is high but the patient cannot undergo a CT angiogram (e.g., renal failure, pregnancy, or unavailability) 
    • interpretation
      • normal
        • rules out PE
      • high-probability
        • treat with heparin
      • low or intermediate probability
        • if clinical suspicion is high, then get a pulmonary angiography
  • Venous duplex ultrasound of the lower extremities
    • indication
      • to evaluate if there are DVTs
Studies
  • ECG
    • findings
      • sinus tachycardia
      • atrial fibrillation
      • right ventricular strain
      • S1Q3T3
        • presence of S wave in lead I and Q wave and inverted T wave in lead III
      • T-wave inversions in V1-V4
  • Arterial blood gas
    • findings
      • hypoxemia
      • hypocapnia
      • respiratory alkalosis
      • alveolar-arterial gradient may be elevated
  • D-dimer
    • has a high sensitivity but poor specificity for PE and a high negative predictive value 
      • used to rule-out PE if there is a low pre-test probability 
Differential
  • Myocardial infarction
    • differentiating factor
      • coronary angiography demonstrating coronary occlusion
  • Costochondritis 
    • differentiating factor
      • pain with palpation or movement of the arm
Treatment
  • Medical
    • Non-vitamin K anticoagulation
      • indication
        • initial therapy in patients with PE in order to prevent further clot formation
          • treatment should not be delayed
      • medication options (best initial step in high risk patient with obvious PE) 
        • low-molecular weight heparin 
          • do not give in renal failure
        • unfractionated heparin 
          • dose by monitoring aPTT
          • preferred in kidney injury/failure
    • warfarin
      • indication
        • typically given around the same time as a non-vitamin K anticoagulant is given
          • dose based on INR (goal is 2-3)
    • thrombolytic therapy
      • indication
        • performed in patients with PE who are hemodynamically unstable
  • Operative
    • embolectomy 
      • indication
        • performed in patients with PE who are hemodynamically unstable and thrombolytic therapy is contraindicated or who fail thrombolysis
    • IVC filter
      • indication
        • performed in patients with PE who have a contraindication or failure of anticoagulation 
Complications
  • Cor pulmonale
  • Recurrent pulmonary embolism
  • Atrial fibrillation or flutter
 
 

Please rate topic.

Average 4.7 of 17 Ratings

Thank you for rating! Please vote below and help us build the most advanced adaptive learning platform in medicine

The complexity of this topic is appropriate for?
How important is this topic for board examinations?
How important is this topic for clinical practice?
Questions (11)
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.PL.62) A 50-year-old man presents to the emergency department with chest pain. He states that it began earlier today and worsens with inspiration. It is non-exertional, 7/10 in severity, and sharp in nature. He states that he just returned from China yesterday and has not had any similar symptoms prior to today. He noticed that he has coughed up a small amount of blood-tinged sputum several times as well. He is otherwise healthy, other than having his foot splinted 4 days ago for an Achilles tendon injury he sustained while playing volleyball. His temperature is 97.9°F (36.6°C), blood pressure is 112/68 mm Hg, pulse is 120/min, respirations are 23/min, and oxygen saturation is 92% on room air. Physical exam is notable for an uncomfortable man who is mentating appropriately and moving all his extremities. Inspection of his lower extremities reveals a swollen and tender calf on the leg that is splinted. An ECG is seen in Figure A. The patient is started on IV fluids and oxygen. Which of the following is the next best step in management? Review Topic

QID: 103425
FIGURES:
1

CT angiogram

20%

(1/5)

2

D-dimer

0%

(0/5)

3

Heparin

20%

(1/5)

4

Tissue plasminogen activator

60%

(3/5)

5

Ultrasound

0%

(0/5)

M2

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

(M2.PL.4687) A 25-year-old woman with bipolar disorder and schizophrenia presents to the emergency room stating that she is pregnant. She says that she has been pregnant since she was 20 years old and is expecting a baby now that she is breathing much harder and feeling more faint with chest pain caused by deep breaths. Her hospital medical record shows multiple negative pregnancy tests over the past 5 years. The patient has a 20 pack-year smoking history. Her temperature is 98°F (37°C), blood pressure is 100/60 mmHg, pulse is 110/min, respirations are 28/min, and oxygen saturation is 90% on room air. Her fingerstick glucose is 100 mg/dL. She has a large abdominal pannus which is soft and nontender. Her legs are symmetric and non-tender. Oxygen is provided via nasal cannula. Her urine pregnancy test comes back positive and an initial chest radiograph is unremarkable. What is the next best step in diagnosis? Review Topic

QID: 107464
1

CT angiogram

5%

(11/204)

2

D-dimer

38%

(77/204)

3

Psychiatry consult for pseudocyesis

30%

(61/204)

4

Ultrasound

13%

(27/204)

5

Ventilation-perfusion scan

11%

(23/204)

M2

Select Answer to see Preferred Response

PREFERRED RESPONSE 5
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(M3.PL.51) A 43-year-old woman presents to her primary care physician with complaints of mild shortness of breath and right-sided chest pain for three days. She reports that lately she has had a nagging nonproductive cough and low-grade fevers. On examination, her vital signs are: temperature 99.1 deg F (37.3 deg C), blood pressure is 115/70 mmHg, pulse is 91/min, respirations are 17/min, and oxygen saturation 97% on room air. She is well-appearing, with normal work of breathing, and no leg swelling. She is otherwise healthy, with no prior medical or surgical history, currently taking no medications. The attending has a low suspicion for the most concerning diagnosis and would like to exclude it with a very sensitive though non-specific test. Which of the following should this physician order? Review Topic

QID: 103342
1

Obtain spiral CT chest with IV contrast

0%

(0/1)

2

Obtain ventilation-perfusion scan

0%

(0/1)

3

Obtain chest radiograph

0%

(0/1)

4

Order a lower extremity ultrasound

0%

(0/1)

5

Order a D-dimer

100%

(1/1)

M2

Select Answer to see Preferred Response

PREFERRED RESPONSE 5

(M3.PL.70) A 64-year-old female with a known diagnosis of metastatic breast cancer presents to the emergency department after decompensating while at the chemotherapy suite. On arrival vitals are: pulse 124 bpm, blood pressure 92/64 mmHg, temperature 98.5 F, respiration 24/min and shallow. The patient is diaphoretic and disoriented, but able to complain about excruciating chest pain. Labs are drawn, and the patient is quickly worked up with an EKG (Figure A) and helical CT (Figure B). The patient is started on a heparin drip. Which of the following results confers a poor prognosis for the patient? Review Topic

QID: 102699
FIGURES:
1

Elevated white blood cell count

0%

(0/0)

2

Decreased d-dimer

0%

(0/0)

3

Elevated d-dimer

0%

(0/0)

4

Elevated troponin

0%

(0/0)

5

Decreased ionized calcium

0%

(0/0)

M2

Select Answer to see Preferred Response

PREFERRED RESPONSE 4
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
ARTICLES (12)
Topic COMMENTS (23)
Private Note