Pleurisy – inflammation of pleura, usually producing an exudative pleural effusion and stabbing chest pain worsened by respiration and cough.
Pleurisy may result from an underlying lung process (eg, pneumonia, infarction, irritating substance into the pleural space (eg, with a ruptured esophagus, amebic empyema, or pancreatic pleurisy); transport of an infectious or noxious agent or neoplastic cells to the pleura via the bloodstream or lymphatics; parietal pleural injury (eg, trauma, especially rib fracture, or epidemic pleurodynia /due to coxsackievirus B/); asbestos-related pleural disease in which asbestos particles reach the pleura by traversing the conducting airways and respiratory tissues; or, rarely, pleural effusion related to drug ingestion.
The pleura usually first becomes edematous and congested. Cellular infiltration follows, and fibrinous exudate develops on the pleural surface. The exudate may be reabsorbed or organized into fibrous tissue resulting in pleural adhesions. In sme diseases (eg, epidemic pleurodynia), the pleurisy remains dry or fibrinous, with no significant exudaiton of fluid from the inflamed pleura. More often, pleural exudate develops from an outpouring of fluid rich in plasma proteins from damaged capillaries. Occasionally, marked fibrous or even calcific thickening of pleura (eg, asbestos pleural plaques, idiopathic pleural calcification) develops without an antecedent acute pleurisy.
Symptoms and Signs
Sudden pain is the dominant symptom of pleurisy. Typically, pleuritic pain is a stubbing sensation aggravated by breathing and coughing, but it can vary. It may only a vague discomfort, or it may occur only when the patient breathes deeply or coughs. The visceral pleura is insensitive; pain results from inflammation of parietal pleura, which is mainly innervated by intercostal nerves. Pain is usually felt over the pleuritic site but may be referred to distant regions. Irritation of posterior and peripheral portioms of the diaphragmatic pleura, which are supplied by the lower six intercostal nerves, may cause pain referred to the lower chest wall or abdomen and may simulate intra-abdominal disease. Irritation of the central portion of the diaphragmatic pleura, innervated by the phrenic nerves, causes pain referred to the neck and shoulder.
Respiration is usually rapid and shallow. Motion of the affected side may be limited. Breath sounds may be diminished. A pleural friction rub, although infrequent, is the characteristic physical sign.It may not be accompanied by pleuritic pain, but it usually is. The friction rub varies from a few intermittent sounds that may simulate crackles to a fully developed harsh grating, creaking, or leathery sound synchronous with respiration, heard on inspiration and expiration. Friction sounds due to pleuritis adjacent to the heart (pleuropericardial rub) may vary with the heart beat as well.
When pleural effusion develops, pleuritic pain usually subsides. Percussion dullness, absent tactile fremitus, decreased or absent breath sounds, and egophony at the upper border of the fluid are then noticeable. The larger the effusion, the more obvious the above signs. A large effusion may produce or contribute to dyspnea through diminished lung volume, especially if there is underlying pulmonary disease, mediastinal shift to the contralateral side, and diminished function and recruitment of inspiratory muscles due to an expanded thoracic cage.
Pleurisy is readily diagnosed when characteristic pleuritic pain occurs. A pleural friction rub is pathognomonic. Pleurisy that produces referred abdominal pain is usually differentiated from acute inflammatory abdominal disease by x-ray and clinical evidence of a respiratory process; absence of nausea, vomiting, and disturbed bowel function; marked aggravation of pain by deep breathing or coughing; shallow rapid breathing; and a tendency toward relief of pain by pressure on the chest wall or abdomen. Intercostal neuritis may be confused with pleurisy, but the pain is rarely related to respiration and there is no friction rub. With herpetic neuritis, development of the characteristic skin eruption is diagnostic. Miocardial infarction, spontaneous pneumothorax, pericarditis, and chest wall lesions may simulate pleurisy. A plueral friction rub may be confused with a friction rub of pericarditis (pericardial rub), which is heard best over the left border of the sternum in the third and forth interspaces, is characteristically a to-and-fro sound synchronous with the heartbeat, and is not influenced significantly by respiration.
Chest x-rays are of limited value in diagnosing fibrinous pleurisy. The pleural lesion causes no shadow, but an associated pulmonary or chest wall lesion may. The presence of a pleural effusion, generally small, confirms the presence of acute pleurisy
Treatment of the underlying disease is essential.
Chest pain may be relieved by wrapping the entire chest with two or three 6-in-wide nonadhesive elastic bandages, which must be reapplied once or twice daily. Acetaminophen 0.65 g qid or an NSAID is often effective. Oral narcotics may be necessary, but cough suppression may be not desired.
Adequate bronchial drainage must be provided to prevent pneumonia. A patient receiving narcotics should be urged to breathe deeply and cough when pain relief from the drug is maximal. Antibiotics and bronchodilators should be considered for treatment of associated bronchitis.
x-ray and CT Scan findings
Essentials of Diagnosis
• Development of pulmonary symptoms about 1-2 weeks after possible aspiration, bronchial obstruction, or previous pneumonia.
• Septic fever and sweats, and periodic sudden ex pectoration of large amounts of purulent, foul-smelling, or "musty" sputum. Hemoptysis may occur.
• X-ray density with central radiolucency and fluid level.
Lung abscess develops when necrosis and liquefaction occur in an area where necrotizing pneumonia is present (picture 1-3). Symptoms and signs occur 1-2 weeks after the following events: (1) massive-aspira tion of upper respiratory tract secretions and microbial flora, especially during profound suppression of cough reflex (eg, with alcohol, drugs, unconsciousness, anesthesia, brain trauma); (2) bronchial obstruction (eg, by atelectasis, foreign body, neoplasm); (3) pres ence of pneumonias, especially those caused by gram-negative bacteria or staphylococci; or (4) forma tion of septic emboli from other foci of infection, or, during bacteremia, with pulmonary infarcts. Abscess is more commonly in the lower dependent portions of the lung. The main etiologic organisms are related to the underlying condition, but a dense mixed anaerobic flora is often prominent, particularly when aspiration has occurred.
A. Symptoms and Signs: Onset may be abrupt or gradual. Symptoms include septic fever, sweats, cough, and chest pain. Cough is often nonproductive at onset. Expectoration of foul-smelling brown or gray sputum (anaerobic flora) or of purulent sputum without odor (pyogenic organism) may occur abruptly and in large quantity. Blood-streaked sputum is also common.
Pleural pain, especially with coughing, is common because the abscess is often subpleural. Weight loss, anemia, and pulmonary osteoarthropathy may appear when the abscess becomes chronic (8-12 weeks after onset).
Physical findings may be minimal. Consolidation due to pneumonitis surrounding the abscess is the most frequent finding. Rupture into the pleural space produces signs of fluid or pneumothorax.
B. Laboratory Findings: Sputum cultures are usually inadequate in determining the bacterial cause of a lung abscess. Transtracheal aspirates should be obtained with the proper technique employed to cul ture anaerobic organisms in addition to the usual aerobic cultures. Special methods of transporting specimens are required for anaerobic organisms, and appropriate culture media and methods must be employed.
Smear and cultures for the tubercle bacilli are required, especially in lesions of the upper lobe and in chronic abscess.
C. X-Ray Findings: A dense shadow is the initial finding. A central radiolucency, often with a visible fluid level, appears as surrounding densities subside. Computerized tomography can supply the detailed lo calization of the abscess and may also reveal primary lesions (eg, bronchogenic carcinoma) and provide guidance for contemplated surgery. Various x-ray pro cedures also permit localization of pleural involvement to facilitate drainage.
D. Instrumental Examination: Fiberoptic bronchoscopy may help to 'diagnose location and nature of obstructions (foreign body, tumor), obtain specimens for microbiologic and pathologic examina tion, and, occasionally, aid drainage.
Differentiate from other causes of pulmonary cavitation: tuberculosis, bronchogenic carcinoma, mycotic infections, and staphylococcal or gram-nega tive bacterial pneumonia.
Postural drainage and bronchoscopy are impor tant to promote drainage of secretions.
A. Acute Abscess: Intensive antibacterial ther apy is necessary to prevent further destruction of lung tissue. While cultures and sensitivity tests are pending, treatment should be started with penicillin G, 2-6 million units daily. In penicillin hypersensitivity clindamycin and chloramphenicol are alternatives. If the patient improves on antimicrobial drugs (and postural drainage),
the drugs should be continued for 4—8 weeks. If the patient fails to respond significantly to the initial treatment, laboratory results may suggest other antimicrobials, eg, nafcillin for staphylococci, cefotaxime for Klebsiella, cefoxitin or metronidazole for mixed anaerobes. Postural drainage is important adjunctive treatment. Percutaneous catheter drainage has been used successfully in selected cases. Surgical therapy is indicated mainly for severe hemoptysis and for me infrequent abscesses that fail to respond to antimicrobial management. Failure of fever to subside after 2 weeks of therapy, abscess diameter of more than 6 cm, and very thick cavity waits are all factors that lessen the likelihood of success with nonsurgical treatment alone.
B. Chronic Abscess: After acute systemic man ifestations have subsided, the abscess may persist. Although many patients with chronic lung abscess can be cured with long-term treatment with antibacterial agents, surgery may occasionally be required.
Rupture of pus into the pleural space (empyema) causes severe symptoms: increase in fever, marked pleural pain, and sweating; the patient becomes “tox ic" in appearance. Adequate drainage of empyema is mandatory. In chronic abscess, severe and even fatal hemorrhage may occur. Metastatic brain abscess is a well-recognized complication, and the infection may seed other organ sites. Bronchiectasis may occur as a sequela to lung abscess even when the abscess itself is cured.
The prognosis in acute abscess is excellent with prompt and intensive antibiotic therapy. About 80% of patients are healed within 7-8 weeks. The incidenee of chronic abscess is consequently low; Inchronic cases, surgery is curative.
Essentials of Diagnosis:
• Chronic cough with expectoration of large amounts of purulent sputum; hemoptysis.
• Rales and rhonchi over lower lobes.
• X-ray of chest reveals little; bronchograms show characteristic dilatations.
Bronchiectasis is a dilatation of small and medium-sized bronchi resulting from destruction of bronchial elastic and muscular elements. It may be, caused by pulmonary infections (eg, pneumonia, per tussis, tuberculosis) or by a bronchial obstruction (eg, foreign bodies or extrinsic pressure). In many patients, a history of onset following one or more episodes of pulmonary infection, usually in early childhood, is obtained. However,since infection does not regularly produce significant bronchiectasis, unknown intrinsic host factors presumably are present. The incidence of
the disease has been reduced by treating pulmonary infections with antibiotics.
A. Symptoms and Signs: Most patients with bronchiectasis have a history of chronic cough with expectoration of large volumes of sputum, especially upon awakening. The sputum has a characteristic qual ity of "layering out" into 3 layers upon standing, a frothy top layer, a middle clear layer, and a dense particulate bottom layer. It is usually purulent in ap pearance and foul-smelling.
Intermittent hemoptysis, occasionally in dangerous proportions, is often combined with intercurrent respiratory infections. Symptoms occur most often in patients with idiopathic bronchiectasis (ie, childhood respiratory infections). However, patients who have bronchiectasis secondary either to tuberculosis or chronic obstruction may not exhibit characteristic symptoms. Idiopathic bronchiectasis occurs most fre quently in the middle and lower lobes and posttuberculous bronchiectasis in the upper lobes. Hemoptysis is thought to result from erosion of bronchiolar mucosa with resultant destruction of un derlying blood vessels. Pulmonary insufficiency may result from progressive destruction of pulmonary tis sue.
Physical findings consist primarily of rales and rhonchi over the affected segments. If the condition is far-advanced, emaciation, cyanosis, and digital club bing may appear.
B. Laboratory Findings: There are no charac teristic laboratory findings. If hypoxemia is chronic and severe, secondary polycythemia may develop. There may be either restrictive or obstructive pulmo nary function defects associated with bronchiectasis. Hypoxemia and hypocapnia or hypercapnia may also be associated with the disease, depending on the se verity of the underlying condition. .
C.X-Ray Findings (figure 1-6): Plain films of the chest often show increased bronchopulmonary markings in af fected segments; in severe cases there may be areas of radiodensities surrounding portions of radiolucency. Early in the course of bronchiectasis, however, the chest x-ray may be normal.
The differential diagnosis includes other disorders that lead to chronic cough, sputum produc tion, and hemoptysis, ie, chronic bronchitis, tuber culosis, and bronchogenic carcinoma. The diagnosis of bronchiectasis is suggested by the patient's history and can be confirmed only by bronchographic examination or histopathologic examination of surgically removed tissue.
Recurrent infection in poorly drained pulmonary segments leads to chronic suppuration and may cause pulmonary insufficiency. Complications include hemoptysis, respiratory failure, chronic cor pulmonale, and amyloidosis. There is also an increased incidence of brain abscess, which is thought to be secondary to abnormal anastomoses between bron chial (systemic) and pulmonary venous circulation. These anastomoses produce right-to-left shunts and allow for the dissemination of septic emboli.
. A. General Measures and Medical Treatment:
1. Environmental changes- The patient should avoid exposure to all common pulmonary irritants such as smoke, fumes, and dust and should stop smoking cigarettes.
2. Control of bronchial secretions (improved drainage)-
a. Postural drainage often gives effective relief of symptoms and should be utilized in every case. The patient should assume the position that gives maximum drainage, usually lying on a bed in the prone, supine, or right or left lateral decubitus position with the hips elevated on several pillows and no pillow under the head. Any effective position should be main tained for 10 minutes, 2-4 times a day. The first drainage should be done upon awakening and tee last drainage at bedtime. Family members can be trained in the art of chest percussion to facilitate drainage of secretions.
b. Liquefaction of thick sputum may be pro moted by inhaling warm mists and, in some cases, mucolytic agents such as acetylcysteine or 5% sodium bicarbonate given by aerosol may also be helpful.
3. Control of respiratory infection-Exposure to respiratory infections should be minimized and the patient should be vaccinated against influenza and pneumococcal pneumonia. Antibiotic therapy is indicated for acute exacerbations (ie, increased production of purulent sputum, hemoptysis, etc). Long-term or prophylactic antibiotic therapy is controversial, since it has not been conclusively shown to be of lasting benefit. Therefore, it seems rational to treat acute exacerbations in order to control infection but mini mize the emergence of resistant strains. Because the bacteria most commonly involved are H inftuenzae and S pneumoniae, the drug most commonly employed is ampicillin, 250-500 mg orally every 6 hours for 5 days. Alternative therapies for the penicillin-allergic patient are erythromycin, given in the same dosage schedule as ampicillin, or trimethoprim-sulfamethoxazole, 2 double-strength tablets twice a day for 5 days.
B. Surgical Treatment: Surgical treatment is most often employed when hemoptysis with bron-chiectasis is recurrent and severe. Despite antibiotic therapy, localized bronchiectasis (eg, in a lower lobe or segment) with progressive uncontrolled infection and sputum production may be an indication for surgical removal of the affected segments.
Bronchiectasis is also associated with mucoviscidosis. It is thought to be secondary to the thick viscid secretions that cannot be cleared by normal cough mechanisms and that lead to stasis of.sputum and chronic infection. This disorder, usually associated with sinusitis, may be accompanied by other manifes tations of mucoviscidosis. Its most common organisms are S aureus or Pseudomonas aeruginosa.
Bronchiectasis is also associated with certain ab normalities of cellular ciliary function, the mostcommon of which is Kartagener's syndrome, a combina tion of sinusitis, situs in versus, andbronchiectasis. Patients with this disorder show immotile cilia second ary to ultrastructural abnormalities, stasis of sputum, failure to clear secretions, and chronic pulmonary infection that results in bronchiectasis.
Antibiotic treatment of mucoviscidosis and Kartagener's syndrome must be guided by sensitivity studies of organisms cultured from sputum.
Iodized contrast media instilled into the bronchial tree (a bronchogram) demonstrates saccular, cylindric, or fusiform dilatation of small and medium bronchi with consequent loss of the normal branching pattern. Cylindric changes of bronchiectasis that may result from acute pneumonia will revert to normal after 6-8 weeks, but saccular dilatations represent long-standing damage and permanent disease.
Patients with Cor Pulmonale
CHRONIC COR PULMONALE
Background: Cor pulmonale is defined as an alteration in the structure and function of the right ventricle caused by a primary disorder of the respiratory system. Pulmonary hypertension is the common link between lung dysfunction and the heart in cor pulmonale. Right-sided ventricular disease caused by a primary abnormality of the left side of the heart or congenital heart disease is not considered cor pulmonale, but cor pulmonale can develop secondary to a wide variety of cardiopulmonary disease processes. Although cor pulmonale commonly has a chronic and slowly progressive course, acute onset or worsening cor pulmonale with life-threatening complications can occur.
Pathophysiology: Several different pathophysiologic mechanisms can lead to pulmonary hypertension and, subsequently, to cor pulmonale. These pathogenetic mechanisms include (1) pulmonary vasoconstriction due to alveolar hypoxia or blood acidemia; (2) anatomic compromise of the pulmonary vascular bed secondary to lung disorders, eg, emphysema, pulmonary thromboembolism, interstitial lung disease; (3) increased blood viscosity secondary to blood disorders, eg, polycythemia vera, sickle cell disease, macroglobulinemia; and (4) idiopathic primary pulmonary hypertension. The result is increased pulmonary arterial pressure.
The right ventricle (RV) is a thin-walled chamber that is more a volume pump than a pressure pump. It adapts better to changing preloads than afterloads. With an increase in afterload, the RV increases systolic pressure to keep the gradient. At a point, further increase in the degree of pulmonary arterial pressure brings significant RV dilation, an increase in RV end-diastolic pressure, and circulatory collapse. A decrease in RV output with a decrease in diastolic left ventricle (LV) volume results in decreased LV output. Since the right coronary artery, which supplies the RV free wall, originates from the aorta, decreased LV output diminishes blood pressure in the aorta and decreases right coronary blood flow. This is a vicious cycle between decreases in LV and RV output.
Right ventricular overload is associated with septal displacement toward the left ventricle. Septal displacement, which is seen in echocardiography, can be another factor that decreases LV volume and output in the setting of cor pulmonale and right ventricular enlargement. Several pulmonary diseases cause cor pulmonale, which may involve interstitial and alveolar tissues with a secondary effect on pulmonary vasculature or may primarily involve pulmonary vasculature. Chronic obstructive pulmonary disease (COPD) is the most common cause of cor pulmonale in the United States.
Cor pulmonale usually presents chronically, but 2 main conditions can cause acute cor pulmonale: massive pulmonary embolism (more common) and acute respiratory distress syndrome (ARDS). The underlying pathophysiology in massive pulmonary embolism causing cor pulmonale is the sudden increase in pulmonary resistance. In ARDS, 2 factors cause RV overload: the pathologic features of the syndrome itself and mechanical ventilation. Mechanical ventilation, especially higher tidal volume, requires a higher transpulmonary pressure. In chronic cor pulmonale, right ventricular hypertrophy (RVH) generally predominates. In acute cor pulmonale, right ventricular dilatation mainly occurs
right ventricular dilatation
- In the US: Cor pulmonale is estimated to account for 6-7% of all types of adult heart disease in the United States, with chronic obstructive pulmonary disease (COPD) due to chronic bronchitis or emphysema the causative factor in more than 50% of cases. Although the prevalence of COPD in the United States is about 15 million, the exact prevalence of cor pulmonale is difficult to determine because it does not occur in all cases of COPD and the physical examination and routine tests are relatively insensitive for the detection of pulmonary hypertension. In contrast, acute cor pulmonale usually is secondary to massive pulmonary embolism. Acute massive pulmonary thromboembolism is the most common cause of acute life-threatening cor pulmonale in adults. In the United States, 50,000 deaths are estimated to occur per year from pulmonary emboli and about half occur within the first hour due to acute right heart failure.
- Internationally: Incidence of cor pulmonale varies among different countries depending on the prevalence of cigarette smoking, air pollution, and other risk factors for various lung diseases.
Mortality/Morbidity: Development of cor pulmonale as a result of a primary pulmonary disease usually heralds a poorer prognosis. For example, patients with COPD who develop cor pulmonale have a 30% chance of surviving 5 years. However, whether cor pulmonale carries an independent prognostic value or it is simply reflecting the severity of underlying COPD or other pulmonary disease is not clear. Prognosis in the acute setting due to massive pulmonary embolism or ARDS has not been shown to be dependent on presence or absence of cor pulmonale.
History: Clinical manifestations of cor pulmonale generally are nonspecific. The symptoms may be subtle, especially in early stages of the disease, and mistakenly may be attributed to the underlying pulmonary pathology.
- The patient may complain of fatigue, tachypnea, exertional dyspnea, and cough.
- Anginal chest pain also can occur and may be due to right ventricular ischemia (it usually does not respond to nitrates) or pulmonary artery stretching.
- Hemoptysis may occur because of rupture of a dilated or atherosclerotic pulmonary artery. Other conditions, such as tumors, bronchiectasis, and pulmonary infarction, should be excluded before attributing hemoptysis to pulmonary hypertension. Rarely, the patient may complain of hoarseness due to compression of the left recurrent laryngeal nerve by a dilated pulmonary artery.
- Variety of neurologic symptoms may be seen due to decreased cardiac output and hypoxemia.
- In advanced stages, passive hepatic congestion secondary to severe right ventricular failure may lead to anorexia, right upper quadrant abdominal discomfort, and jaundice.
- Syncope with exertion, which may be seen in severe disease, reflects a relative inability to increase cardiac output during exercise with a subsequent drop in the systemic arterial pressure.
- Elevated pulmonary artery pressure can lead to elevated right atrial pressure, peripheral venous pressure, and then capillary pressure and by increasing the hydrostatic gradient, it leads to transudation of fluid, which appears as peripheral edema. Although this is the simplest explanation for peripheral edema in cor pulmonale, other hypotheses explain this symptom, especially in a fraction of patients with COPD who do not show increase in right atrial pressure. A decrease in glomerular filtration rate (GFR) and filtration of sodium and stimulation of arginine vasopressin (which decreases free water excretion) due to hypoxemia play important pathophysiologic roles in this setting and may even have a role for peripheral edema in patients with cor pulmonale who have elevated right atrial pressure.
Physical: Physical findings may reflect the underlying lung disease or pulmonary hypertension, RVH, and RV failure.
- On inspection, an increase in chest diameter, labored respiratory efforts with retractions of chest wall, distended neck veins with prominent a or v waves, and cyanosis may be seen.
- On auscultation of the lungs, wheezes and crackles may be heard as signs of underlying lung disease. Turbulent flow through recanalized vessels in chronic thromboembolic pulmonary hypertension may be heard as systolic bruits in the lungs. Splitting of the second heart sound with accentuation of the pulmonic component can be heard in early stages. A systolic ejection murmur with sharp ejection click over the region of the pulmonary artery may be heard in advanced disease, along with a diastolic pulmonary regurgitation murmur. Other findings upon auscultation of the cardiovascular system may be third and fourth sounds of the heart and systolic murmur of tricuspid regurgitation.
- RVH is characterized by a left parasternal or subxiphoid heave. Hepatojugular reflex and pulsatile liver are signs of RV failure with systemic venous congestion.
- On percussion, hyperresonance of the lungs may be a sign of underlying COPD; ascites can be seen in severe disease.
- Disorders with primary involvement of pulmonary vasculature and circulation
- Repeated pulmonary emboli
- Pulmonary vasculitis
- Pulmonary veno-occlusive disease
- Congenital heart disease with left-to-right shunting
- Sickle cell disease
- High altitude disease with pulmonary vasoconstriction
- Primary pulmonary hypertension
- Disorders with secondary involvement of pulmonary vasculature and circulation
- Parenchymal lung diseases (interstitial lung diseases, chronic obstructive lung diseases)
- Neuromuscular disorders (eg, myasthenia gravis, poliomyelitis, amyotrophic lateral sclerosis)
- Obstructive and central sleep apnea
- Thoracic deformities (eg, kyphoscoliosis)
Other Problems to be Considered:
Congestive (biventricular) heart failure
Primary pulmonic stenosis
Primary pulmonary hypertension
Right-sided heart failure due to congenital heart diseases
Right heart failure due to right ventricular infarction
- A general approach to diagnose cor pulmonale and to investigate its etiology starts with routine laboratory tests, chest radiography, and electrocardiography. Echocardiography gives valuable information about the disease and its etiology. Pulmonary function tests may become necessary to confirm the underlying lung disease. Ventilation/perfusion (V/Q) scan or chest CT scan may be performed if history and physical examination suggest pulmonary thromboembolism as the cause or if other diagnostic tests do not suggest other etiologies. Right heart catheterization is the most accurate but invasive test to confirm the diagnosis of cor pulmonale and gives important information regarding the underlying diseases. Any abnormal result in each of these tests may need further diagnostic evaluation in that specific direction.
- Laboratory investigations are directed toward defining the potential underlying etiologies as well as evaluating complications of cor pulmonale. In specific instances, appropriate lab studies may include the following: hematocrit for polycythemia (which can be a consequence of underlying lung disease but can also increase pulmonary arterial pressure by increasing viscosity), serum alpha1-antitrypsin if deficiency is suspected, and antinuclear antibody level for collagen vascular disease such as scleroderma. Hypercoagulability states can be evaluated by serum levels of proteins S and C, antithrombin III, factor V Leyden, anticardiolipin antibodies, and homocysteine.
- Arterial blood gas tests may provide important information about the level of oxygenation and type of acid-base disorder.
- Elevated brain natriuretic peptide (BNP) level alone is not adequate to establish presence of cor pulmonale, but it helps to diagnose cor pulmonale in conjunction with other noninvasive tests and in appropriate clinical settings. An elevated BNP level may actually be a natural mechanism to compensate for elevated pulmonary hypertension and right heart failure by promoting diuresis and natriuresis, vasodilating systemic and pulmonary vessels, and reducing circulating levels of endothelin and aldosterone.
- Imaging studies may show evidence of underlying cardiopulmonary diseases, pulmonary hypertension, or its consequence, right ventricular enlargement.
- Chest roentgenography: In patients with chronic cor pulmonale, the chest radiograph may show enlargement of the central pulmonary arteries with oligemic peripheral lung fields. Pulmonary hypertension should be suspected when the right descending pulmonary artery is larger than 16 mm in diameter and the left pulmonary artery is larger than 18 mm in diameter. Right ventricular enlargement leads to an increase of the transverse diameter of the heart shadow to the right on the posteroanterior view and filling of the retrosternal air space on the lateral view. These findings have reduced sensitivity in the presence of kyphoscoliosis or hyperinflated lungs.
- Echocardiography (picture 12): Two-dimensional echocardiography usually demonstrates signs of chronic right ventricular pressure overload. As this overload progresses, increased thickness of the right ventricular wall with paradoxical motion of the interventricular septum during systole occurs. At an advanced stage, right ventricular dilatation occurs and the septum shows abnormal diastolic flattening. In extreme cases, the septum may actually bulge into the left ventricular cavity during diastole resulting in decreased diastolic volume of LVand reduction of LV output.
Doppler echocardiography is used now to estimate pulmonary arterial pressure, taking advantage of the functional tricuspid insufficiency that is usually present in pulmonary hypertension. Doppler echocardiography is considered the most reliable noninvasive technique to estimate pulmonary artery pressure. The efficacy of Doppler echocardiography may be limited by the ability to identify an adequate tricuspid regurgitant jet, which may be further enhanced by using saline contrast.
(A) Parasternal long axis view obtained from a patient admitted for septic shock secondary to a severe aortic endocarditis (arrows indicate vegetations) associated with a massive regurgitation and dilated left ventricle. (B) Parasternal short axis view obtained from a patient with an acute respiratory distress syndrome and associated cor pulmonale. The right ventricle was markedly enlarged and the ventricular septum bulged towards the left ventricular cavity at end systole, due to severe pulmonary hypertension (arrow). (C) Apical four-chamber view obtained from a ventilated patient with refractory hypoxemia. The contrast study (intravenous injection of saline microbubbles) revealed a large interatrial right-to-left shunt through a patent foramen ovale, which participated to persistent hypoxemia: left cardiac cavities were filled up by the microbubbles within two cardiac cycles. (D) Subcostal view obtained from a patient presenting with shock and pulsus paradoxus. A mild pericardial effusion responsible for prolonged right atrial collapse during the cardiac cycle (arrow) was consistent with a tamponade, and the patient underwent successful pericardotomy. LV, left ventricle; RV, right ventricle; LA, left atrium; RA, right atrium; Ao, ascending aorta.
- Ventilation/perfusion (V/Q) lung scanning, pulmonary angiography, and chest CT scanning may be indicated to diagnose pulmonary thromboembolism as the underlying etiology of cor pulmonale. These tests may be performed early in the diagnostic workup if any evidence of pulmonary embolism appears in history and physical examination. The test may also be considered later in the workup if other tests are not suggestive of any other etiology. Pulmonary thromboembolism has a wide range of clinical presentations from massive embolism with acute and severe hemodynamic instability to multiple chronic peripheral embolisms that may present with cor pulmonale.
- Ultrafast, ECG-gated CT scanning has been recently evaluated to study RV function. In addition to estimating right ventricular ejection fraction (RVEF), it can estimate RV wall mass. Its use is still experimental, but with further improvement, it may be used to evaluate the progression of cor pulmonale in the near future.
- Magnetic resonance imaging (MRI) of the heart is another modality that can provide valuable information about RV mass.
- Radionuclide ventriculography can determine RVEF noninvasively.
- Electrocardiography (ECG): ECG abnormalities in cor pulmonale reflect the presence of RVH, RV strain, or underlying pulmonary disease. These electrocardiographic changes may include right axis deviation, R/S amplitude ratio in V1 greater than 1 (increase in anteriorly directed forces may be a sign of posterior infarct), R/S amplitude ratio in V6 less than 1, P-pulmonale pattern (an increase in P wave amplitude in leads 2, 3, and aVF), S1Q3T3 pattern and incomplete (or complete) right bundle branch block, especially if pulmonary embolism is the underlying etiology, low-voltage QRS because of underlying COPD with hyperinflation and increased AP diameter of the chest. Severe RVH may reflect as Q waves in the precordial leads that may be interpreted as anterior myocardial infarction by mistake (on the other hand, since electrical activity of the RV is significantly less than the LV, small changes in RV forces may be lost in ECG).