- Acute onset of dyspnea, pleuritic chest pain, tachypnea, tachycardia
- Hypoxemia with widened A-a gradient
- Pulmonary angiogram is gold standard
A variety of clinical conditions may cause clots to form in the venous system that when dislodged will cause pulmonary emboli (Table 33–3). Venous thrombosis may result from a generalized hypercoagulable state, venous endothelial injury, or local stasis (Virchow triad). Clots that cause clinically significant pulmonary emboli form most commonly in the iliofemoral and pelvic venous beds. Pulmonary embolization, from veins of the upper extremities or distal lower extremities, is unusual and rarely clinically significant.
Table 33–3. Conditions that Predispose to Pulmonary Embolization. ||Download (.pdf)
Table 33–3. Conditions that Predispose to Pulmonary Embolization.
- Venous stasis
- Prolonged immobility (eg, bed rest, stroke)
- Chronic obstructive pulmonary disease
- Congestive heart failure
- Venous endothelial damage
- Surgery within past 3 months
- Fractures of long bones or hip
- Lower extremity trauma
- Malignant neoplastic disease
- Use of oral contraceptives
- Marked obesity
- Protein C or S deficiency
- Antithrombin III deficiency
- Presence of factor V Leiden
- Previous history of deep venous thrombosis or pulmonary embolism
When embolization occurs, the manifestations depend on the size of the embolism, the patient's underlying cardiorespiratory status, and whether subsequent infarction of pulmonary tissue occurs. With small to medium sized emboli, obstruction of a localized portion of the pulmonary vascular tree causes local atelectasis with resulting ventilation–perfusion (V/Q) abnormalities and hypoxemia. Reflex hyperventilation with resultant hypocapnia and tachycardia also occurs. With massive embolization (obstructing over 60% of the vascular bed), acute pulmonary hypertension, right heart strain, systemic hypotension, and shock may also occur. Pulmonary emboli may also present with sudden cardiovascular collapse and death.
The illness often begins abruptly, and a predisposing underlying condition is almost always present. Dyspnea and chest pain are the usual presenting symptoms. Tachycardia and hypoxia are the most common clinical signs. Fever, hypotension, cyanosis, pleural friction rub, and pulmonary consolidation may be the result of PE but are usually the result of other illnesses when they occur.
Laboratory and Other Findings
The chest X-ray is abnormal in most patients with pulmonary embolization with infarction but the abnormalities are often nonspecific (eg, atelectasis, pleural effusions, small infiltrates). The Westermark sign (dilated pulmonary vasculature proximal to embolus with oligemia distal) and Hampton's Hump (a pleural-based density with a rounded border facing the hilum) are more suggestive though uncommon findings with pulmonary emboli.
The electrocardiogram is often abnormal, usually demonstrating tachycardia or diffuse nonspecific ST-T abnormalities. The classic finding of acute right heart strain (S1/Q3/T3; T-wave inversion in leads V1–V3) is more specific but somewhat uncommon.
A clinically significant PE is usually but not always associated with hypoxemia (oxygen saturation < 90%; Po2 < 80 mm Hg). Hyperventilation and hypocapnia are also common findings. An arterial puncture is required to measure the arterial Pco2 and calculate an alveolar-arterial oxygen gradient (A-a gradient). The value of the A-a gradient over the more easily measured oxygen saturation by pulse oximetry is minimal. Most of the time the additional time, discomfort and expense is not justified by any additional discriminatory ability of the A-a gradient.
The serum levels of the D-dimer (a degradation product of crosslinked fibrin) have been shown to be a highly sensitive (95%) screening examination for the formation of acute thrombus. The test is nearly always positive in patients with recent trauma or surgery or any process that produces bleeding and requires hemostasis. In patients who are at low risk for PE (low pretest probability) a negative test can be helpful in ruling out PE. Patients who are not at low risk should undergo a more definitive test such as CT scanning.
The Geneva score is a clinical decision tool that can be used in the diagnostic evaluation of patients with suspected PE. The original score was revised to preclude the need for arterial blood gasses. The revised and simplified Geneva score (Table 33–4) has the same diagnostic utility as the original score and its calculation is more reliable. A simplified score of 0-2 indicates the patient is unlikely to have a PE and when combined with a normal D-dimer test, the clinical probability of a PE is 3% or less.
Table 33–4. Simplified Revised Geneva Score. ||Download (.pdf)
Table 33–4. Simplified Revised Geneva Score.
|Age greater than 65 years||1|
|Previous DVT or PE||1|
|Surgery (under general anesthesia) or fracture (of lower limbs) within 1 month.||1|
|Active malignant condition (solid or hematologic, currently active or considered cured < 1 year||1|
|Unilateral lower-limb pain||1|
|Heart rate 75–94|
|Heart rate greater than or equal to 95||1|
|Pain on lower-limb deep venous palpation and unilateral edema||1|
Contrast-Enhanced CT Scan
Contrast-enhanced CT scan allows for rapid evaluation and is accurate but requires intravenous contrast enhancement and expert radiographic interpretation. The technology has improved in recent years and now includes automated bolus injection and fast, high-resolution, multislice CT scanners. CT scanning also provides a wealth of information regarding other chest pathologies, such as pneumonia, pleural effusion, masses, and vascular pathology, such as aneurysms. Contrast allergy is sometimes an issue. Pretreatment with steroids and antihistamines can be done if a contrast allergy is suspected and the study is necessary.
Ventilation–Perfusion Radionuclide Lung Scan (V/Q Scan)
V/Q scanning has been replaced with contrast-enhanced CT scanning except in cases of contrast allergy. A normal perfusion scan essentially excludes significant embolization. In many patients the perfusion scan will not be normal (most commonly with COPD) and the ventilation scan is used to look for areas of mismatched ventilation and perfusion. A high-probability V/Q scan is defined as a large perfusion defect in areas of normal ventilation and is highly specific (but insensitive) for acute pulmonary emboli. An indeterminate V/Q scan (also reported as nondiagnostic, low probability, or intermediate probability) is more difficult to use clinically.
Venous Doppler Ultrasound
Doppler ultrasound is a noninvasive test used in the diagnosis of deep venous thrombosis. The test is sensitive and specific. A positive venous Doppler lends supportive evidence that the patient has thrombosis; however, thrombosis can occur without embolization. Many patients with significant pulmonary emboli are asymptomatic in their lower extremities and have negative lower extremity Doppler studies.
The diagnostic accuracy of pulmonary angiography is considered to be the best of any procedure available. Frequently, CT images are convincing enough to be considered pathognomonic and in that case angiography does not offer a diagnostic advantage. Angiography requires right heart catheterization, which is usually done only as part of thrombolytic treatment for patients hemodynamically compromised by the size of the embolus.
Correct hypoxemia with supplemental oxygen. Patients with large emboli may be hypotensive and require resuscitation with intravenous fluids. Pressors and positive pressure ventilation are poorly tolerated and should be avoided unless absolutely necessary.
Anticoagulation is the standard treatment and should be administered as soon as the diagnosis of pulmonary embolization is made. If a delay in diagnosis is anticipated and there are no contraindications, patients may be treated presumptively. This most often occurs when CT scanning is not available and the patient must be transferred to another institution or held overnight.
The usual dose of unfractionated heparin (UFH) is an initial 80 IU/kg bolus followed by 18 IU/kg/h infusion. Many institutions have protocols for heparinization and the use of one is recommended. Low-molecular weight heparin (LMWH) (enoxaparin 1 mg/kg SC q 12 hours or dalteparin 200 units /kg/day SC divided qd to BID) and fondaparinux(a factor Xa inhibitor) 7.5 mg SC qd are as effective and safe as UFH and are more convenient. Compared with UFH, LMWH and fondaparinux are more expensive medications but may reduce the total hospital cost and length of stay.
Although anticoagulation is sufficient treatment for most patients with pulmonary emboli, a few patients who present with hemodynamic compromise may benefit from thrombolytic therapy via a pulmonary artery catheter. Peripherally administered thrombolytic treatment has not been shown to be of value.
A transvenous catheter embolectomy or open surgical embolectomy may be a lifesaving maneuver in a patient with massive emboli and refractory hypotension. The usual indication for a vena cava filter is the failure of anticoagulation to prevent thromboembolism.
Hospitalize all patients for continued anticoagulation and supportive care. Patients with hemodynamic impairment, or those receiving thrombolytics, should be monitored in the ICU. Patients in whom PE is strongly suspected should be hospitalized for anticoagulation (if no contraindications are present) until a definitive diagnosis can be made.
Adam SS, Key NS, Greenberg CS: D-dimer antigen: current concepts and future prospects. Blood 2009;113:2878–2887
Costantino MM, Randall G, Gosselin M, Brandt M, Spinning K, Vegas CD: CT angiography in the evaluation of acute pulmonary embolus. Am J Roentgenol 2008;191:471–474
Klok FA, Mos IC, Nijkeuter M, Righini M et al: Simplification of the revised Geneva score for assessing clinical probability of pulmonary embolism. Arch Intern Med 2008;168:2131–2136
The most common cause of hemoptysis, bronchitis, is primarily a diagnosis of exclusion. The more significant causes such as cancer, tuberculosis, and autoimmune disorders such as Goodpasture's syndrome are uncommon but still deserve consideration in the patient who admits to coughing up blood. A list of conditions that cause hemoptysis is discussed in Table 33–5. Massive hemoptysis is defined in terms of volume as 200–600 cc in 24 hours. This broad range is in part a manifestation of the difficulty of measuring the volume of expectorated blood. Many patients with life-threatening hemopysis are elderly and have associated co-morbid conditions.
Table 33–5. Conditions Causing Hemoptysis. ||Download (.pdf)
Table 33–5. Conditions Causing Hemoptysis.
- Pulmonary hemoptysis
- Pulmonary parenchymal disease
- Lung abscess
- Fungal infection of old cavities (eg, aspergilloma)
- Lung parasites (ascariasis, schistosomiasis, etc)
- Pulmonary neoplasms
- Pulmonary infarction
- Arteriovenous malformations
- Pulmonary vasculitis
- Goodpasture's syndrome
- Extrapulmonary disease
- Other coagulopathies
- Heart failure
- Mitral stenosis
- Nonpulmonary hemoptysis
- Aspiration of blood from nasal, oropharyngeal, gastrointestinal, or other bleeding site
- Production of red-tinged sputum not due to blood
Hemoptysis is the coughing of blood. This needs to be clearly differentiated from the vomiting of blood (hematemesis) as the diagnostic approach is different. If a patient complains of spitting blood, this may mean that the blood is not being coughed into the oropharynx. The blood may be from the mouth, nose, or nasopharynx and not of tracheobronchial origin. It is important to clarify a history of spitting blood.
The vital signs are important as is the presence of pallor or cyanosis. Physical findings in the chest are generally nonspecific but may indicate the presence of effusions, pulmonary masses, or airspace disease such as that due to bloody fluids in the alveoli. The heart examination may be abnormal due to the presence of a cardiovascular cause of hemoptysis such as mitral stenosis.
Patients who appear pale or report significant blood loss should be evaluated for anemia. Coagulation studies should be obtained on patients who take warfarin or have liver disease and blood gases on patients in severe respiratory distress.
A chest X-ray is an important study in patients with hemoptysis. CT scanning of the chest should be considered in the diagnostic evaluation if the initial plain film is abnormal and nondiagnostic. Angiography may be necessary if bleeding is massive and offers the possibility of treatment via embolization.
Treatment of hemoptysis in the emergency department usually is limited to general supportive care. An upright position is preferred. If the patient must be recumbent they should be positioned with the radiographically normal (presumably nonbleeding) lung up. If intubation is necessary large-bore endotracheal tubes (greater than 7.5) are helpful in facilitating fiberoptic bronchoscopy.
Rigid bronchoscopy and selective intubation of the nonbleeding lung should be considered if bleeding is massive. The use of a double-lumen tube may be preferable but is technically more challenging. Endobronchial therapy during bronchoscopy may be successful in controlling the bleeding.
Ninety per cent of massive hemoptysis is due to bleeding from the bronchial rather than the pulmonary circulation. Selective embolization of the involved bronchial arterial segment is effective in controlling the bleeding in about 90% of patients. The major risk of this technique is spinal cord ischemia, which may be minimized by selective techniques that avoid embolization of the anterior spinal artery.
Surgical resection of the involved lobe or pulmonary segment may be necessary but depends on a localized site of bleeding. The patient must have adequate pulmonary reserve, have focal disease, and be an acceptable surgical candidate.
Massive hemoptysis requires ICU admission and a team approach involving the pulmonologist, interventional radiologist, and the thoracic surgeon. Most patients with minimal degrees of hemoptysis due to bronchitis can be managed as outpatients. Patients who are suspected of having pulmonary tuberculosis should be isolated and treated presumptively until definitive studies can be completed.
Bidwell JL, Pachner RW: Hemoptysis: diagnosis and management. Am Fam Physician 2005;72:1253–1260
Van Den Berg JC: Bronchial artery embolization. In Golzarian J, Sun S, Sharafuddin MJ (editors). Vascular embolotherapy: A comprehensive approach. Volume 1 General Principles, Chest, Abdomen, and Great Vessels. New York, NY: Springer; 2006:263–278.
Pulmonary Arterial Hypertension (PAH)
- Exertional shortness of breath or syncope
- Absence of congestive changes on chest X-ray
- Loud pulmonic closure, P2
Pulmonary hypertension may be secondary to another lung disorder such as COPD, left-sided heart disease, or recurrent pulmonary thrombo-embolic disease. Pulmonary arterial hypertension (PAH) is a diagnosis category that is not a secondary result of the aformentioned causes but does include familial types and those associated with collagen vascular diseases such as scleroderma, HIV infection, and toxic exposures. Anatomically this disorder is characterized by the remodeling of the pulmonary circulation with occlusion of the lumen in the medium-sized and small pulmonary arteries. The afterload of the right ventricle increases as this occurs which causes an obstruction to flow in the pulmonary arterial tree and increases the pressure as the right ventricle attempts to compensate.
Common symptoms are shortness of breath especially with exertion. Exertional syncope may also be a presenting complaint. Pulmonary venous hypertension from congestive heart failure causes shortness of breath while lying flat while PAH typically does not. A loud pulmonic closure, P2 may be present on auscultation. Peripheral edema may occur.
Imaging and Laboratory Findings
PAH, may be suspected, may be identified with echocardiography but diagnosis requires measurements of pressure and flow with a Swan-Ganz catheter. Pulmonary artery wedge pressure should be less than 15 mm Hg and the pulmonary artery pressure greater than 25 mm Hg to make the diagnosis.
Treatment and Disposition
Phosphodiesterase Type 5 Inhibitors
Phosphodiesterase type 5 inhibitors were first developed to treat erectile dysfunction but also are effective in patients with PAH who have symptoms that are mild to moderately severe. Sildenafil is marketed as Revatio(TM) when used to treat PAH instead of Viagra(TM), and tadalafil is marketed as Adciraca(TM) instead Cialis(TM) for this indication.
In severe disease epoprostenol (synthetic prostacyclin, marketed as Flolan(TM)) is indicated. Since the drug lasts only 3–5 minutes it must be administered by continuous infusion via a central venous catheter. These patients may be seen in emergency situations with complications from the indwelling catheter but the major issue is that the interruption of the infusion may cause rapid reversal of symptoms. This can be life threatening. Immediate consultation with the patient's pulmonologist should be obtained if this is suspected.
Humbert M: Update in pulmonary hypertension 2008. Am J Respir Crit Care Med 2009;179:650–656