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Emergency Medicine Review Infectious Disorders Program Name School Name.

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Presentation on theme: "Emergency Medicine Review Infectious Disorders Program Name School Name."— Presentation transcript:

1 Emergency Medicine Review Infectious Disorders Program Name School Name

2 PNEUMOTHORAX A. Pathophysiology (air in pleural space, lung cannot inflate) 1. Primary a. Occurs in people with no prior history of chest or lung disease b. Males predominate 5 to 1 (traditionally tall, thin) c. Valsalva d. Bleb formation is the underlying defect e. Over 90% of patients are smokers f. Recurrence is common % g. Also associated with congenital abnormalities i. Marfan's syndrome ii. Ehlers-Danlos syndrome iii. Cystic fibrosis 2. Secondary pneumothorax (underlying lung disease) a. Asthma b. COPD c. Interstitial lung disease d. Malignancy e. Pneumonia with abscess/cavitation 3. Catamenial pneumothorax; associated with menses

3 PNEUMOTHORAX 4. Iatrogenic a. Mechanical ventilation b. Central lines c. Thoracentesis B. Clinical presentation 1. Chest pain (sudden, pleuritic) 2. Dyspnea 3. Unilateral decreased breath sounds and tympany 4. Hyperresonance 5. Subcutaneous emphysema (not common) 6. Hamman's crunch with mediastinal air C. Chest radiograph 1. Loss of lung markings peripherally 2. Inspiratory/expiratory 3. Decubitus in children 4. Extent usually underestimated

4 PNEUMOTHORAX D. Treatment 1. Oxygen for all patients 2. Primary pneumothorax less than 20% a. Observe b. Analgesics c. Discharge home 3. Primary pneumothorax greater than 20% a. Needle decompression (catheter aspiration) b. Observe in hospital overnight c. If resolves, discharge home next morning d. If recurs, chest tube e. Analgesics

5 PNEUMOTHORAX 4. Indications for tube thoracostomy in a patient with a pneumothorax a. Traumatic cause b. Moderate to large size c. Respiratory symptoms regardless of the size of the pneumothorax d. Increasing size of pneumothorax after initial conservative therapy e. Recurrence of pneumonia after removal of initial chest tube f. Patient requires ventilatory support g. Patient requires general anesthesia h. Associated hemothorax i. Bilateral pneumothoraces j. Tension pneumothorax (needle first)

6 PNEUMOTHORAX 5. Failure of simple aspiration for spontaneous pneumothorax is significantly associated with two factors a. Age over 50 b. Large volume of aspiration 6. Re-expansion pulmonary edema a. Typical patient i. Large pneumothorax ii. Minimally symptomatic patient iii. Pneumothorax duration of greater than 3 days (typically 1 week) iv. Rapid rate of lung re-expansion b. To avoid re-expansion pneumothorax i. Do not set to suction ii. Use Heimlich valve on these patients and take out 200 mL of air every 1 hour (volume controlled re-expansion) E. Tension pneumothorax 1. Pleural defect creates a one-way valve and leads to positive pressure in pleural space 2. Clinical presentation a. Mediastinal shift b. Tracheal deviation (clinically difficult to detect) c. Hypotension d. Neck vein distention

7 PNEUMOTHORAX 3. Can kill if goes unrecognized 4. Treatment a. Needle decompression before chest tube insertion b. Chest tube thoracostomy until leak closes F. Prevention of complications 1. Avoid tube malposition (abdominal and thoracic) a. Use anterior axillary fold (not nipple) b. Superior posterior direction 2. Aseptic technique 3. Watch connections, kinking, etc. 4. Chest radiograph after procedure

8 PNEUMOMEDIASTINUM A. Pathophysiology 1. Extrapleural tear in tracheobronchial tree a. Intrathoracic b. Trachea and major bronchi c. Esophagus d. Lung e. Pleural space f. Extrathoracic g. Head and neck h. lntraperitoneum and retroperitoneum B. Clinical presentation 1. Retrosternal chest pain radiating down both arms worse with breathing or swallowing 2. Throat or jaw pain, dysphonia, dysphagia, neck swelling or torticollis 3. Hamman's crunch (crunching sound heard over apex of heart with every heartbeat) 4. Air in neck (look at neck on x-ray) 5. Watch for worsening condition 6. Watch it in infants a. Cardiovascular compromise by compression of hilum

9 PNEUMOMEDIASTINUM C. Diagnostic evaluation 1. Chest radiograph a. Subcutaneous emphysema b. Air in neck (take neck x-ray) c. Thymic sail sign d. Pneumoprecardium e. Ring around the artery sign f. Tubular artery sign g. Double bronchial wall sign h. Continuous diaphragm sign i. Extrapleural sign

10 PULMONARY EMBOLISM (PE) A. Epidemiology 1. Common cause of death in the U.S. a. Incidence unknown i. 2,000,000 Americans suffer from DVT annually ii. 500,000 die from PE annually, 12% have no identified risk factors b. Most common presentation i. Progressive occlusion of the pulmonary vasculature over weeks (55%) c. Unexplained dyspnea i. Strongest independent predictor of PE in ambulatory patients d. Hemoptysis i. Strong independent predictor of PE in ambulatory patients e. Clinical probability i. Most important f. High mortality (9- 20%) i. Two-thirds occur within first hour g. Of initial survivors i. 30% die if untreated ii % die with treatment h. Often presents as a perplexing diagnostic and therapeutic challenge i. No routine historical, clinical or laboratory findings are specific or sensitive enough to make the diagnosis

11 PULMONARY EMBOLISM (PE) B. Virchow's triad 1. Venous stasis a. Immobilization, long travel b. General anesthesia c. CHF, COPD d. Venous insufficiency e. Obesity 2. Intimal damage a. Trauma b. Postoperative 3. Hypercoagulability a. Malignancy b. Pregnancy c. Estrogen d. Inherited e. Autoimmune disease C. Hypercoagulable disorders 1. Factor V Leiden (activated protein C resistance) 2. Protein C and S deficiency

12 PULMONARY EMBOLISM (PE) 3. Antithrombin Ill deficiency 4. Antiphospholipid antibody syndrome 5. Plasminogen deficiency 6. Factor XII deficiency 7. Hyperhomocysteinemia 8. Dysplasminogenemia 9. Dysfibrinogenemia 10. Prothrombin 2021 A mutation 11. Indications for test a. Event occurs in less than 40-year-old patient b. Recurrent thromboembolism events c. Family history of thromboembolism events D. Major risk factors for PE 1. Surgery a. Abdominal, knee/hip, postoperative, ICU 2. Obstetrics a. Late pregnancy, peripartum, C-section

13 PULMONARY EMBOLISM (PE) 3. Malignancy a. Advanced, metastatic, abdominal/pelvic 4. Immobilization a. Hospitalized, institutional care 5. 12% of patients with proven PE do not have any risk factors E. Wells' criteria 1. Clinical suspicion for DVT CriteriaPoints Suspected DVT3 Alternative diagnosis more likely3 Tachycardia> Immobilization/surgery < 4 weeks1.5 Previous DVT1.5 Hemoptysis1 Active cancer1 Low suspicion:< 2 (1.3%) Moderate suspicion: 2- 6 (16% High suspicion: > 6 (37%)

14 PULMONARY EMBOLISM (PE) F. Revised Geneva Score Risk FactorsPoints Age> 651 History of DVT or PE3 Surgery or fracture within 1 month2 Active malignancy2 Symptoms Unilateral leg pain3 Hemoptysis2 Clinical Signs Heart rate Heart rate > 955 Pain on leg vein palpation and unilateral edema4 Clinical Probability: Low: 0-3 Intermediate: 4 – 10 High: > 10

15 PULMONARY EMBOLISM (PE) G. Pulmonary embolism rule-out criteria (PERC)- low-risk patient only 1. Criteria a. Age less than 50 b. Pulse less than 100 c. Sa02 greater than 94% d. No unilateral leg swelling e. No hemoptysis f. No recent trauma or surgery (4 weeks) g. No prior PE or DVT h. No estrogen use 2. Less than 2% chance that patient has a PE H. Clinical presentation 1. History a. Dyspnea 80%+ b. Chest pain 75% C. Cough 60% d. Apprehension 60% e. Hemoptysis less than 30% f. Sweating less than 25% g. Syncope less than 1 0%

16 PULMONARY EMBOLISM (PE) 2. Physical examination a. Tachypnea 90% b. Rales 60% c. Loud P2 50% d. Tachycardia(> 90) 45% e. Fever 50% f. Signs of DVT 40% I. PIOPED patients a. 933 randomly selected for trial b. 755 had comparative angiogram c. 383 patients with proven PE i. 80% were dyspneic ii % had pleuritic chest pain iii % had a cough iv. 75% were tachypneic (greater than 20) v. 55% had rales vi % had tachycardia (greater than 90) vii. 95% had at least one of a) Dyspnea, tachypnea, pleuritic chest pain

17 PULMONARY EMBOLISM (PE) J. KEY CONCEPT 1. You must consider PE in any patient with dyspnea or hypoxemia (Sa02Iess than 93%) K. More facts about PE 1. Of those with symptomatic PE, % will have evidence of asymptomatic DVT on ultrasound 2. Alternatively, of those with symptomatic DVT, % will have asymptomatic PEon V/Q 3. 80% of patients with fatal PE have DVTs in the lower extremities 4. One in five patients who present to the ED with signs and symptoms consistent with PE have isolated DVT as their only VTE diagnosis (i.e., no clot on CTA but clot on US legs) 5. Take Home Lesson: With a high pretest probability of PE (gestalt high), you must do venous ultrasound of the legs if CTA-positive and repeat the venous ultrasound of the legs in three-to seven-days 6. 50% of patients with iliofemoral DVT embolize 7. Calf thrombosis propagates and embolizes in 20% of patients 8. Sensitivity of diagnosis of DVT by clinical examination is only 50% 9. Published reports have noted that 33% of patients with PE had the most proximal portion of their clot below the knee 10. Untreated calf thrombus has a % risk of proximal extension, usually within the first week 11 As the leg clot matures and breaks off, venous Doppler may become negative as the CT A becomes positive

18 PULMONARY EMBOLISM (PE) L. Massive PE 1. RV gallop 2. RV lift (best heard along the left sternal border) 3. Loud pulmonary closure 4. Prominent "a" waves in jugular pulse 5. Systolic or continuous murmur over lung 6. Wide splitting of S2 M. Diagnostic evaluation 1. Pulse oximetry a. Normal pulse oximetry does not exclude pulmonary embolism (15% will have normal) 2. A-a gradient (not much help) a. Widened A-a gradient i. Some have normal A-a gradient (less than 5%) ii. A-a gradient is the PA02 (alveolar)- Pa02 (arterial) iii. PA02 = X PaC02 iv. A-a gradient = (PaC02/0.8 + Pa02) v. Normal A-a gradient= age/4 + 4 vi. Quicky A-a gradient= 140-(Pa02+PaC02)

19 PULMONARY EMBOLISM (PE) 3. EGG (greater than 85% abnormal) a. Sinus tachycardia most common b. Nonspecific ST-T changes common in rightward leads c. Right heart strain pattern d. RBBB e. S103T3 (uncommon, large PE) f. T wave inversion in II, Ill, aVF, V1-V3 4. Chest radiograph a. Of patients with PE, 30% will have a normal chest radiograph on presentation b. 20% will demonstrate an elevated hemidiaphragm c. Approximately 17% will eventually develop parenchymal infiltrates d. A normal chest radiograph in a dyspneic, hypocapnic, hypoxemic patient makes the diagnosis of PE e. Less commonly i. Hampton's hump a) Pleural based infiltrates with rounded borders facing hilum ii. Westermark's sign a) Dilated pulmonary vasculature proximal toembolus with oligemia distal iii. Fleischner's sign a) Infiltrates enlarged or cut off pulmonary arterioles

20 PULMONARY EMBOLISM (PE) 5. Laboratory a. There are no lab tests to date that will prove or disprove the diagnosis of PE b. Clotting function tests are often normal in patients with PE c. The hemoglobin and hematocrit is commonly normal in patients with PE, but the finding of polycythemia should raise a red flag as this entity is a risk factor for PE d. The WBC may be normal or it may be elevated as high as 20,000 e. The sedimentation rate is commonly normal in thromboembolic conditions f. The platelet count is commonly normal in PE g. The combination of elevated AST, LDH, and bilirubin were once believed to be specific for PE, but this has not panned out · h. D-dimer i. High sensitivity, low specificity; great for NPV ii. Types of D-dimer a) Latex: cannot trust it!!! b) SimpliRED: erythrocyte agglutination c) Turbimetric: latex, turgiquant d) NycoCard D-dimer: immunofiltration iii. False negatives a) Small clots b) Delayed presentation (greater than 7 days)

21 PULMONARY EMBOLISM (PE) iv. False positives a) Sepsis b) Ml c) Liver disease d) Advanced age e) Trauma f) Postoperative g) HIV infection h) Idiopathic i) Cancer j) Pregnancy v. Perform a D-dimer on a patient with low clinical probability of PE a) If you are at moderate probability clinically, then D-dimer is no help b) Do not use latex D-dimer unless it is the immunoturbinometric dimer

22 PULMONARY EMBOLISM (PE) vi. Inappropriate patients for D-dimer testing a) Heart rate greater than systolic BP b) Age greater than 70 c) Unexplained saturations less than 95% d) Unilateral leg swelling e) Hemoptysis f) Recent major surgery g) If you suspect PE clinically or you do not suspect cancer vii. 95% of the following patients will have positive Ddimers a) Surgery in the past seven days b) Age greater than 70 c) Pregnant patients (100% in third trimester) d) Patients with active cancer i. New diagnostic tests for pulmonary embolism i. Evidence supports use of second generation D-dimer tests as an aid in PE screening ii. Low clinical probability with negative D-dimer, less than 1% had PE in one study j. INR and PE i. Risk of recurrent thromboembolism a) Decreases considerably when INR greater than 3.0 b) Increases dramatically when INR less than 2.5 ii. Recurrent thromboembolism may occur in spite of full anticoagulation

23 PULMONARY EMBOLISM (PE) 6. Doppler ultrasound a. 85% of PEs arise from DVT in the legs b. Less invasive than pulmonary angiography in cases of equivocal V/Q scan c. Ultrasound is much more sensitive for thigh DVT than calf DVT d. Repeat US in three-to-seven days increases sensitivity e. Withholding anticoagulation is safe if US is negative f. "For patients with suspected PE, venous studies are very helpful when positive, but of no value when negative" g. "Embolism from DVT is so common that finding DVT in a patient with symptoms of PE essentially proves the diagnosis of PE" 7. Two types of lung scans a. Perfusion scans b. Ventilation/perfusion scans c. PIOPED i. Negative V/Q scan virtually rules out embolic disease (90%+ accuracy) ii. The bad news is that PE was proven in 9% of the PIOPED patients who had.angiography after a normal V/Q scan!! iii. PIOPED classifies V/Q scans into four classifications a) Normal b) Low probability c) Intermediate probability d) High probability

24 PULMONARY EMBOLISM (PE) iv. Scans classified as intermediate have a) A sensitivity of 82% and PPV for PE of 33% b) This means that if an intermediate probability V/Q result is presumed positive, that will be wrong 67% of the time; whereas if it is presumed negative, it will miss 18% of PE cases c) An intermediate probability V/Q scan does not change the prior clinical likelihood that a given patient has had a PE v. Low probability V/Q scans have a) A sensitivity for PE of 98%; PPV of 14% for PE b) This means that if a low probability scan is presumed positive, this will be wrong 86% of the time; yet if it is presumed negative, this will miss the diagnosis of PE in 02% of patients with PE c) A low probability V/Q pattern does not change the prior clinical likelihood that a given patient has had aPE vi. High probability V/Q scans have a) A sensitivity of 41% and a PPV for PE of 87% b) This means that if a high probability V/Q scan is presumed positive, this will be wrong 13% of the time; whereas if it is presumed negative it will miss 59% of cases of PE

25 PULMONARY EMBOLISM (PE) V/Q Scan Clinical Science Probability >80% 20%-80% 80% 20%-80%<20% Both High -Treat Both Low- No Treat High 96% 88% 56% Intermediate 66% 28% 16% Low 40%16% 4% Near Norm 10%6% <2% 8. Clinical prediction rule for PE a. Low probability (3.4% risk) i. No risk factors, atypical ii. Another likely alternative diagnosis b. Moderate probability (27.4% risk) i. Risk factors, typical, another likely alternative diagnosis ii. No risk factors, typical, no alternative diagnosis iii. Risk factors, atypical, no alternative diagnosis iv. Typical-severe, another likely alternative diagnosis

26 PULMONARY EMBOLISM (PE) c. High probability (78.4% risk) i. Risk factors, atypical, no likely alternative diagnosis ii. Typical-severe, no likely alternative diagnosis 9. KEY CONCEPTS a. Take home message on V/Q scans i. If the V/Q scan is negative (rare) and the clinical suspicion is low, you can stop chasing ii. If the V/Q scan is high probability, you should treat iii. Anything else lacks sensitivity and specificity and should be considered nondiagnostic b. V/Q scans will be indeterminate in patients with rapid respiratory rates c. 75% of V/Qs are nondiagnostic d. V/Q is more likely to be diagnostic in the young without underlying cardiopulmonary conditions 10. Spiral CT in the evaluation of PE a. Less contrast than angiography b. Detects other important, unsuspected diagnoses that may account for the patients symptoms i. Mediastinal tumors ii. Bronchogenic cancer iii. Postirradiation fibrosis iv. Aortic dissection v. Pneumonia (small) vi. Pneumothorax (small)

27 PULMONARY EMBOLISM (PE) c. Advantages over lung scan i. Quicker ii. Identifies other diseases iii. Overall accuracy better (especially with COPD, pneumonia, etc.) d. False positives i. Tortuous arteries or arteries seen on an angle ii. Movement artifact or cardiac motion iii. Atelectasis e. False negatives i. Smaller defects ii. Subsegmental defects f. Disadvantages CT A i. Disadvantages over lung scan a) Subsegmental emboli i) Not seen on spiral CT ii) Non diagnostic on V/Q scan ii. 8% of ED patients develop laboratory defined "contrast nephropathy" (i.e., 25% increase in creatinine) iii. Baseline creatinine does not predict who will get contrast nephropathy

28 PULMONARY EMBOLISM (PE) iv. Lifetime risk of fatal malignancy from 1 CT scan is 1 in 500 v. Higher for patients <40 years old; double that in women vi. 45% of patients who get one CTA will get a second CTA within the next 5 years vii. Positive CTA in low risk patient (42% of patients will have false positive and will be treated and should not) g. Implications for clinical practice i. Patients clinically suspected of having a PE with a positive D-dimer should undergo a pulmonary vascular imaging including angiography if other tests are negative ii. A spiral CT has good overall performance in the evaluation of PE iii. A positive spiral CT should prompt you to give anticoagulation 11. MRI in the evaluation of patients with PE a. Low sensitivity b. Able to see central PE only (or large segmental) c. Getting better d. Readerdependent

29 PULMONARY EMBOLISM (PE) N. Prophylaxis 1. Heparin (low molecular weight heparin [LMWH] vs. Heparin) 2. Surgery patients greater than 40 years old a. Thoracoabdominal b. Orthopedic c. Gynecologic 3. Pregnant patients with past history of DVT 0. Treatment of acute thrombosis/embolus 1. Heparin a U/Kg bolus then U/Kg/hour, use nomogram if not; 50% of your patients are not going to be therapeutic in 24 hours b. If patients are not therapeutic in 24 hours, then they have 15 times the chance of developing PE 2. LMWH a. Lovenox® 1 mg/kg Q-12-H 3. Coumadin a. Begin day one and continue i. For 3 months if no persistent risks ii. For 6 months if recurrent disease, persistent cancer or clotting disorder 4. Greenfield IVC filter for multiple or massive DVT

30 PULMONARY EMBOLISM (PE) P. Thrombolysis 1. Indications a. ACEP Clinical Policy: Critical issues in the evaluation and management of adult patients presenting with suspected pulmonary embolism i. Level B: use in hemodynamically unstable patients with confirmed PE ii. Level C: use in hemodynamically stable patients with RV dysfunction iii. Level C: use in hemodynamically unstable patients with high index of suspicion for PE Q. Surgical embolectomy 1. Anticoagulation contraindicated 2. Critical condition unlikely to survive with delay of medical therapy 3. Consider thrombolytics or Heparin in these patients 4. Venous ligation or plication is rarely used R. Approximately 25% of patients who survive their first PE will have a clinically recognized recurrence, even if appropriately diagnosed and managed

31 PULMONARY EMBOLISM (PE) S. KEY CONCEPT 1. The smaller the clots the more likely everything is to not show up positive a. Clinically b. Radiographically c. D-dimer d. V/Q lung scan e. Doppler f. Spiral CT g. ABGs, EGG, other T. Caval filters are not a substitute for anticoagulation. Small clots can passthrough the filter; or clots may originate above the filter. With time, filters may become a problem U. PE and pregnancy 1. The most common cause of nonsurgical maternal death in the peripartum period 2. Biggest risk for overall VTE (PE and DVT) is in the first week postpartum 3. Biggest risk of PE is early in pregnancy in the younger female Patient 4. PE risk for all females is 1:10,000 which increases during pregnancy to 1:1,000

32 PULMONARY EMBOLISM (PE) 5. D-dimer adjustment during pregnancy a. VIDAS D-dimer measurements i. 1st trimester: 750 ng/ml ii. 2nd trimester: 1000 ng/ml iii. 3rd trimester: 1200 ng/ml b. PERC rule adjustment i. Heart rate less than 1 05 c. Dimer (adjusted) negative+ PERC (adjusted) negativestop chasing 6. Venous Doppler a. Greater than 50% of pregnant patients with PE have no DVT (i.e., venous Doppler would not see anything) 7. VQ scans will be normal in% of pregnant patients a. Dose of radiation from VQ scan is 1 /5th to 1/1 Oth that of a CT A i. Can reduce radiation exposure further by a) Using% microcurie dose b) Prehydration c) Foley catheter ii. A negative VQ scan is more sensitive than a negative CT scan 8. CT A is still the gold standard but has risks to mother and fetus (dye has been found in fetal kidneys)

33 PULMONARY EMBOLISM (PE) 9. Strategy a. Adjusted D-dimer + adjusted PERC rule - this alone can reduce number of CTAs by 30% b. Venous Dopplers first (if clot, treat) 10. Treatment: heparin not Coumadin® V. Bottom line 1. Risk less than 15% + negative PERC - stop chasing 2. Risk greater than 15% but still low (defined as non-high pretest probability) + negative D-dimer- stop chasing 3. If risk is high, do appropriate evaluation 4. CTA is becoming the gold standard 5. A negative CTA of good quality rules out PE 6. High-risk patients who have a negative CTA need venous Dopplers and may require follow up study in 3 to 7 days 7. Low-risk patients should not get CTAs; too many false positives 8. VQ is still an excellent test if you do not suspect lung disease 9. Which patients do we miss? a. Admitted patients i. With multiple comorbidities ii. Older patients with altered mental status (dementia, OBS, previous CVA)- not good historians b. Discharged patients i. Young, obese females on BCP with normal VS

34 QUESTIONS Which of the following is true regarding patients with low V/Q ratios? A. Hypoxemia B. Increased pC02 C. A-a gradient on RA decreased D. 1 00% oxygen decreases gradient E. High altitude may cause this 2. Which of the following is true regarding patients with diffusion defects? A. Increased pC02 B. Normal A-a gradient on RA C. Hypoxemia D. Increased FI02 does not correct hypoxemia E. Increased FI02 does not correct A-a gradient 3. Which of the following physical signs of PE is the most common? A. Tachycardia B. Rales C. Fever D. Signs of DVT E. Loud P2

35 QUESTIONS 4. A 24-year-old with no past history presents with a 1 0% pneumothorax. What is the recommended treatment? A. Needle decompression B. Observation C. Tube thoracostomy D. Surgery 5. Which of the following is not true for pneumomediastinum? A. Children may have cardiac compromise B. Patients do not need to be admitted C. Air may be present in the neck on radiograph D. Hamman's crunch may be heard

36 ANSWERS 1. A - Hypoxemia 2. E - lncreased FI02 does not correct A-a gradient 3. B - Rales 4. B - Observation 5. B - Patients do not need to be admitted


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