Pφ

Following a marked decline in the incidence of TB in the United States over several decades, the incidence escalated dramatically and peaked in 1992. In the United States, important risk factors for TB infection are as follows: close contact with a person infected with TB; immigration from an endemic area (e.g., Africa, Asia, or Latin America); exposure to persons with untreated cases of TB in congregate living facilities (e.g., homeless shelters, correctional facilities, nursing homes, or other health care facilities); age; and residence in high-incidence locations (e.g., inner cities or foreign endemic areas). HIV-associated TB accounts for approximately 10% of TB cases in the United States; among TB patients between 25 and 44 years of age, 22% are known to be infected with HIV. A majority of TB cases in the United States now occur in foreign-born individuals emigrating from countries with high rates of endemic TB. The majority of cases of TB are caused by Mycobacterium tuberculosis, and the lungs are the major site of infection. Pulmonary manifestations of TB include primary, reactivation, endobronchial, and lower lung field infection. Reactivation TB represents 90% of adult cases in the non-HIV-infected population and results from reactivation of a previously dormant focus seeded at the time of the primary infection.

TP

Low-grade fever lasting 14–21 days, chest pain, fatigue, cough, sputum production, night sweats, weight loss, arthralgias, and pharyngitis are some common symptoms. The physical examination is usually normal; pulmonary signs included pain to palpation and signs of an effusion. Complications of TB (i.e., hemoptysis, pneumothorax, bronchiectasis, and in some cases extensive pulmonary destruction) can also involve the lung. Most common sites of extrapulmonary involvement include the pleura, lymph nodes (particularly cervical and hilar), central nervous system (CNS) (as meningitis or tuberculoma), genitourinary system, blood, and bone marrow. TB can cause massive hemoptysis by sudden rupture of a Rasmussen aneurysm; this is an aneurysm of the pulmonary artery that slowly expands into an adjacent cavity because of inflammatory erosion of the external vessel wall, causing it to rupture.

Dx

The most common abnormality on chest radiography is hilar adenopathy, occurring in 65% of patients. Pleural effusions, pulmonary infiltrates, nodules, and cavitations are also seen in varying frequency. The standard skin tuberculin test consists of 0.1 mL (5 tuberculin units) of purified protein derivative (PPD) administered subcutaneously, usually on the volar surface of the forearm. The reaction is read 48 to 72 hours after injection as induration, which suggests a history of infection with TB but does not mean that the patient has tuberculous disease. Similarly, positive blood tests (interferon-γ release assays that measure how the immune system reacts to the bacterium that causes TB) suggest that the patient has tuberculous infection but should not be used to diagnose active TB. Sputum samples for acid-fast bacilli smear and culture are an important diagnostic tool. If the smear is negative, bronchoscopy with brushings or bronchoalveolar lavage and transbronchial biopsy have been shown to be useful. The diagnosis of drug-resistant TB depends upon the collection and processing of adequate specimens for culture and sensitivity testing before the institution of therapy. Detection of mycobacterial growth on conventional media requires 4 to 8 weeks. Target amplification using nucleic acid amplification tests such as the polymerase chain reaction has been more sensitive than standard techniques.

Pφ

Lung cancer is the most common cause of cancer mortality worldwide for both men and women, causing approximately 1.2 million deaths per year. A number of environmental and lifestyle factors have been associated with the subsequent development of lung cancer, of which cigarette smoking is the most significant. Other risk factors include exposure to radiation therapy, asbestos, radon, metals (arsenic, chromium, and nickel), ionizing radiation, and polycyclic aromatic hydrocarbons. Lung cancers are classified as either small cell or non–small cell lung cancer (SCLC or NSCLC). This distinction is essential for staging, treatment, and prognosis. The relative incidence of adenocarcinoma has risen dramatically, and there has been a corresponding decrease in the incidence of other types of NSCLC and SCLC.

TP

Common symptoms include cough, hemoptysis, chest pain, and dyspnea. Hemoptysis is reported by 25% to 50% of patients who are diagnosed with lung cancer. Lung cancers can often cause a post-obstructive pneumonia. Obstruction of the superior vena cava (SVC) causes symptoms that commonly include a sensation of fullness in the head and dyspnea. Physical findings include dilated neck veins, a prominent venous pattern on the chest, facial edema, and a plethoric appearance. Lung cancers arising in the superior sulcus cause a characteristic Pancoast syndrome manifested by pain (usually in the shoulder, and less commonly in the forearm, scapula, and fingers), Horner syndrome, bony destruction, and atrophy of hand muscles.

The most frequent sites of distant metastasis are the liver, adrenal glands, bones, and brain. Neurologic manifestations of lung cancer include metastases and paraneoplastic syndromes. Symptoms from CNS metastasis are similar to those with other tumors and include headache, vomiting, visual field loss, hemiparesis, cranial nerve deficits, and seizures. Brain metastases are seen in 50% of patients with SCLC at autopsy.

Dx

There are several options for sampling a primary tumor: imaging-guided percutaneous needle aspiration or biopsy, blind transbronchial fine-needle aspiration (TBNA), conventional flexible bronchoscopy with forceps biopsy, and endobronchial ultrasound (EBUS)–guided forceps biopsy.

In patients with pleural effusion, thoracentesis is a simple bedside procedure that permits fluid to be rapidly sampled, visualized, examined microscopically, and quantified. Malignant pleural effusions are typically exudative and may be serous, serosanguineous, or grossly bloody. The yield of pleural fluid cytology after a single thoracentesis (and examination of 50–100 mL) in patients with documented pleural involvement is about 60%.

Pφ

Aspergilloma refers to the disease caused by a “ball” of fungal mycelia that can occur within a cavity, usually within the parenchyma of the lung. It is generally thought that the presence of Aspergillus in pulmonary cavities reflects saprophytic colonization and not actual tissue invasion. An aspergilloma usually arises in a preexisting cavity in the lungs. Any condition that causes cavitation in the lungs may subsequently be associated with the development of an aspergilloma; these include TB, sarcoidosis, neoplasms, other fungal infections such as histoplasmosis or coccidioidomycosis, cystic fibrosis, or invasive aspergillosis. The fungus ball is composed of fungal hyphae, inflammatory cells, fibrin, mucus, and amorphous debris. Within a pulmonary cavity, the mass may be free or attached to the wall of the cavity. The usual species of Aspergillus recovered from such lesions is A. fumigatus, but other species are also found.

TP

Patients with pulmonary aspergilloma can be asymptomatic. The most frequent symptom directly related to the fungal mass is hemoptysis, which may occur in up to 75% of patients. Less commonly, patients can develop chest pain, dyspnea, malaise, wheezing, or fever that may be secondary to the underlying disease, bacterial superinfection of the cavity, or the aspergilloma itself.

Dx

Chest radiography is useful in demonstrating the presence of a mass within a cavity. Typically, there is a solid mass surrounded by a radiolucent crescent (crescent sign, Monod sign). If the fungus ball is mobile, repeating the radiograph with the patient in the lateral decubitus position will show that the mass has moved. When chest radiography does not clearly delineate a cavity, CT scanning of the lungs can be used to demonstrate a cavity and any intracavitary structures. Cultures of the sputum may or may not be positive for the fungus. If there is no communication between the cavity and the bronchial tree, cultures will probably be negative. Sputum cultures, especially a single culture, cannot establish a diagnosis since Aspergillus is a common colonizer of an abnormal respiratory tract. However, the finding of a mass within a pulmonary cavity and the recovery of Aspergillus species, particularly from multiple sputum cultures, is strongly supportive of the diagnosis.

Pφ

A variety of diseases are associated with the development of DAH.

TP

The onset of DAH is most often abrupt or of short duration (less than 7 days). Cough, hemoptysis, fever, and dyspnea are common initial symptoms. Some patients, however, present with acute severe respiratory distress requiring mechanical ventilation. The pulmonary examination is usually nonspecific, unless there are physical signs of an underlying systemic vasculitis or connective tissue disorder.

Dx

The chest radiograph is nonspecific and most commonly shows new patchy or diffuse alveolar opacities. Recurrent episodes of DAH may lead to pulmonary fibrosis and interstitial opacities. Thoracic CT scanning confirms the presence of ground-glass or airspace-filling opacities that are usually diffuse and bilateral but may occasionally be unilateral. Laboratory findings in DAH are often nonspecific. A number of diseases that can result in the pulmonary-renal syndrome present with pulmonary hemorrhage in combination with rapidly progressive glomerulonephritis. In this setting there is an elevated serum creatinine concentration, usually with an abnormal urinalysis (containing red blood cells, white blood cells, proteinuria, and red cell and white cell casts). A positive antinuclear cytoplasmic antibody (ANCA) test can be associated with DAH due to Wegener granulomatosis or microscopic polyarteritis. Perinuclear ANCA (P-ANCA) with antimyeloperoxidase specificity enzyme-linked immunosorbent assay (anti-MPO ELISA) favors the diagnosis of microscopic polyarteritis or Churg-Strauss syndrome. The presence of antibodies specific to glomerular basement membrane (GBM) in the serum is diagnostic for anti-GBM antibody disease (Goodpasture syndrome). Antibodies directed against streptococcal antigens, including those specific to streptolysin O, DNase B, or hyaluronidase, or the documentation of positive blood cultures can suggest a diagnosis of post-streptococcal glomerulonephritis or bacterial endocarditis, respectively. Diagnostic clues can be found from the biopsy of affected tissue (usually kidney or lung).

Pφ

PE refers to obstruction of the pulmonary artery or one of its branches by material (e.g., thrombus, tumor, air, or fat) that originated elsewhere in the body. Most emboli arise from thrombi in the deep venous system of the lower extremities. However, they may also originate in the right side of the heart or the pelvic, renal, or upper extremity veins. Most patients with acute PE have an identifiable risk factor at the time of presentation. These risk factors include immobilization, surgery within the last 3 months, stroke, paralysis, history of venous thromboembolism, malignancy, central venous instrumentation within the last 3 months, and chronic heart disease. Acute PE is a common and often fatal disease. Mortality can be reduced by prompt diagnosis and therapy. Unfortunately, the clinical presentation of PE is variable and nonspecific, making accurate diagnosis difficult. Impaired gas exchange due to PE cannot be explained solely on the basis of mechanical obstruction of the vascular bed and alterations in the ventilation-to-perfusion ratio. Gas exchange abnormalities are also related to the release of inflammatory mediators, resulting in surfactant dysfunction, atelectasis, and functional intrapulmonary shunting.

TP

The most common symptoms are dyspnea at rest or with exertion, pleuritic chest pain, cough, greater than two-pillow orthopnea, hemoptysis, calf or thigh pain, calf or thigh swelling, and wheezing. The onset of dyspnea is usually within seconds or minutes. The most common signs are tachypnea, tachycardia, crackles, decreased breath sounds, an accentuated pulmonic component of the second heart sound, and jugular venous distension.

Dx

Spiral (helical) CT scanning with intravenous contrast is now more commonly being utilized as the test of choice in patients with suspected PE. Other tests for consideration are lower extremity venous ultrasound, ventilation-perfusion (V/Q) scan, and echocardiography. Pulmonary angiography is the definitive diagnostic technique or “gold standard” in the diagnosis of acute PE.