Pulmonary WebPath

A 47-year-old man has lost 6 kg in 5 months. He has had a cough with hemoptysis along with pleuritic chest pain for the past 2 weeks. On physical examination his temperature is 37.5°C. A chest x-ray reveals a bilateral and predominantly upper lobe reticulonodular pattern of infiltrates with cavitation. A sputum sample is obtained and on light microscopic examination shows epithelioid cells with necrotic debris. Laboratory studies show a WBC count of 5890/microliter with 78% granulocytes, 15% lymphocytes, and 7% monocytes. Which of the following additional histologic findings is most likely to be present in his sputum?

Acid fast bacilli. The hemoptysis suggests that the granulomas have eroded enough parenchyma and involved a bronchus. A granulomatous reaction is typical for Mycobacterium tuberculosis infection

A 44-year-old woman, a non-smoker, has had a fever and cough for the past 4 days. She does not have hemoptysis. She has not experienced weight loss, malaise, nausea, or vomiting. On physical examination her temperature is 37.6°C. There are decreased breath sounds over the right upper lung. A chest radiograph reveals a 6 cm area of infiltrates in the right upper lobe. She is given a course of antibiotic therapy, but her cough persists. A month later her chest x-ray now reveals a 3 cm peripheral mass in the right upper lobe. Which of the following neoplasms is most likely to be present in this woman?

Adenocarcinoma. Peripheral lung cancers (adenocarcinoma and large cell carcinoma) show less of an association with smoking than central lung cancers (small cell and squamous cell carcinoma). The focal obstruction from the mass predisposed to infection.

A 61-year-old man has had a cough without production of much sputum for the past week. On physical examination he is afebrile. There are decreased breath sounds at the right lung base. A chest x-ray reveals an area of consolidation in the right lower lobe. He is given antibiotic therapy, but a month later the radiographic picture has not changed, and his cough continues. A bronchoalveolar lavage is performed and yields atypical cells along with scattered alveolar macrophages. Which of the following is the most likely diagnosis?

Adenoccarcinoma-in-situ. Adenocarcinoma-in-situ can spread in a pneumonia-like pattern. The lack of a change over time and the absence of a response to antibiotics should suggest an underlying non-infectious process. Adenocarcinomas may occur in non-smokers.

A 43-year-old woman who does not smoke becomes increasingly dyspneic over 8 years' time. She does not have a cough or increased sputum production. She is afebrile. On physical examination she has decreased breath sounds with hyperresonance in all lung fields. A chest radiograph reveals increased lucency of all lung fields. Laboratory studies show her serum alpha-1-antitrypsin level is 18 mg/dL. Which of the following microscopic portions of the lung is most likely to be affected by her condition?

Alveolar duct. Alpha-1-antitrypsin (AAT) deficiency leads to a panacinar form of emphysema which involves the distal acinus beyond the respiratory bronchiole.

A 41-year-old previously healthy woman, a non-smoker, has had episodes of fever, non-productive cough, and dyspnea over the past 3 months. Her symptoms disappeared after a month's vacation, but reappeared when she returned home to take care of her canaries. On physical examination there are no abnormal findings. A chest radiograph shows fine diffuse and nodular infiltrates in all lung fields. Her disease is most likely to be produced via which of the following inflammatory mechanisms?

Antigen-antibody complex formation. Birds make a lot of organic dust from their feathers. The result upon inhalation of the bird dust is an extrinsic allergic alveolitis. Getting away from the antigen (such as a vacation) will improve the situation. This is a form of type 3 hypersensitivity. It may progress to involve type 4 hypersensitivity if chronic.

A 66-year-old man has had increasing dyspnea for the past year. He is retired from the construction business. There are some rales auscultated in both lungs on physical examination. A chest radiograph reveals bilateral diaphragmatic pleural plaques with focal calcification as well as diffuse interstitial lung disease. A sputum cytology shows no atypical cells, only ferruginous bodies. Pulmonary function studies reveal a low FVC and a normal FEV1/FVC ratio. These findings are most likely to suggest prior exposure to which of the following environmental agents?

Asbestos crystals. These findings are classic for exposure to asbestos. Pleural plaques are more frequent in this condition than in other pneumonconioses, particularly with calcification. Asbestosis is a rare form of pneumoconiosis that can lead to restrictive lung disease. The ferruginous bodies are asbestos fibers encrusted with iron. Building materials from older houses may contain asbestos, which was used for years because of its fire retardant properties.

A 53-year-old man has had increasing dyspnea for the past 6 years, but no cough. On physical examination there is increased jugular venous distension. He is afebrile. A chest radiograph shows increased lucency in upper lung fields and increased lung volumes, with flattening of the diaphragmatic leaves. There are no infiltrates. The pulmonary arteries are enlarged and prominent bilaterally, and his right heart border is enlarged. Which of the following pathologic findings is most likely to be present in his main pulmonary arteries?

Atherosclerosis. Cor pulmonale is the result of pulmonary hypertension, which is the major cause for pulmonary atherosclerosis. His emphysema has reduced the pulmonary vascular bed, promoting the hypertension. Note that the forces driving systemic atherosclerosis are not operative on the pulmonary arterial system.

A 12-year-old girl has the acute onset of dyspnea and wheezing. She coughs up a large, thick mucus plug. She has experienced similar previous episodes for the past 4 years, all of which lasted 1 to 4 hours. On physical examination her vital signs include T 37.1°C, P 109/minute, RR 40/minute, and BP 90/60 mm Hg. There are decreased breath sounds in all lung fields. A chest radiograph reveals hyperinflation but no infiltrates. Laboratory studies show WBC count of 8300/microliter with differential count of 60 segs, 3 bands, 16 lymphs, 10 monos, and 11 eosinophils. A sputum sample examined microscopically has increased numbers of eosinophils. Which of the following is the most likely diagnosis?

Bronchial asthma. In an acute asthmatic episode, there can be an outpouring of mucus which, along with some dehydration, can lead to the formation of mucus plugs. These atopic asthmatic episodes in children are usually initiated by a type I hypersensitivity reaction, typically with exposure to an allergen such as pollen from goldenrod or other flowering plant. Up to 10% of children may be affected to some degree by atopy.

An 8-year-old boy at birth appeared to be a normal term baby, but his neontal course was complicated by the development of meconium ileus. His sweat chloride and immunoreactive trypsinogen are both found to be elevated. Throughout childhood he has experienced multiple increasingly severe bouts of pneumonia with a productive cough, often with Pseudomonas aeruginosa, and later Burkholderia cepacea, cultured from sputum. He is at greatest risk for development of which of the following pulmonary abnormalities?

Bronchiectasis. The chronic lung disease of cystic fibrosis often includes bronchiectasis, a disease characterized by inflammation with obstruction and dilation and destruction of bronchi. This process is diffuse throughout the lungs. The loss of pulmonary vascular bed with progressive bronchiectasis can lead to pulmonary hypertension and cor pulmonale. The sweat chloride is a good screening test, and can be applied as well as immunoreactive trypsinogen, to select for additional genomic testing, but testing is confounded by hundreds of possible CFTR gene mutations.

A male infant has initial Apgar scores of 5 and 6 at 1 and 5 minutes following birth by normal vaginal delivery at 30 weeks gestation. However, increasing respiratory distress in the next hour requires intubation and positive pressure ventilation. Two months later, the infant is finally taken off the ventilator, but still does not oxygenate normally. Which of the following diseases has this infant most likely developed?

Bronchopulmonary dysplasia. The bronchopulmonary dysplasia (BPD) is a complication of the treatment for neonatal respiratory distress. The positive pressure ventilation with the higher FIO2's, and the prolonged intubation, all contribute. Generally, these are premature infants who had a respiratory complication following birth, such as hyaline membrane disease.

A 64-year-old man has a 90 pack year history of smoking. For the past 5 years, he has had a cough productive of copious amounts of mucoid sputum for over 3 months at a time. He has had episodes of pneumonia with Streptococcus pneumoniae and Klebsiella pneumoniae cultured. His last episode of pneumonia is complicated by septicemia and brain abscess and he dies. At autopsy, his bronchi microscopically demonstrate mucus gland hypertrophy. Which of the following conditions is most likely to explain his clinical course?

Chronic bronchitis. Chronic bronchitis is defined clinically as persistent cough with sputum production for at least 3 months in at least 2 consecutive years. Air pollution and smoking are key causes for chronic bronchitis. The alteration of lung parenchyma predisposes to superimposed infection, typically with bacterial organisms.

A 54-year-old woman has had fever and dyspnea for a month along with a 2 kg weight loss. On physical examination her temperature is 37.7°C. A chest radiograph shows a reticulonodular pattern along with prominent hilar lymphadenopathy. A transbronchial lung biopsy is performed, and microscopic examination shows no viral inclusions, no fungi, no acid fast bacilli, and no atypical cells. Which of the following diseases is she most likely to have?

Sarcoidosis. The symptoms and signs are classic for granulomatous disease. Sarcoidosis often involves the hilar lymph nodes as well. No organisms can be found.

A 25-year-old man receives a hematopoietic stem cell transplant for treatment of acute myelogenous leukemia. He develops increasing dyspnea 3 weeks later, along with fever and cough. On physical examination his temperature is 37.8°C. A chest radiograph shows irregular interstitial infiltrates. A bronchoalveolar lavage is performed an on cytologic examination shows cells that are enlarged and have prominent intranuclear inclusions. He is most likely to have an infection with which of the following organisms?

Cytomegalovirus. CMV produces a cytopathic effect with enlarged cells having prominent intranuclear inclusions. CMV infection occurs most often with immune compromise, as in this case folowing transplantation before engraftement.

Following a vehicular accident with blood loss leading to prolonged, severe hypotension, a 30-year-old man is intubated and placed on a mechanical ventilator. He has progressively decreasing oxygen saturations despite increasing PEEP and FIO2 content of 100%. He remains afebrile. He dies 3 days later. At autopsy, the distal lungs show pink hyaline membranes, thickened interstitium, and many macrophages but few neutrophils. Which of the following pulmonary diseases most likely complicated his course?

Diffuse alveolar damage. Diffuse alveolar damage (or ARDS as it is known clinically) is the final event following severe lung injury from a variety of serious illnesses or accidents. In this case, it was probably initiated by the hypotension ('shock lung') and potentiated by the 100% oxygen generating free radical damage.

A 43-year-old woman has had increasing dyspnea for 8 years. She has no cough or increased sputum production. On physical examination there is bilateral hyperresonance to percussion in all lung fields. A chest x-ray reveals increased lung volumes with flattening of the diaphragmatic leaves bilaterally. The right heart border is prominent. A chest CT scan demonstrates decreased attenuation in all lung fields, particularly lower lobes. Which of the following laboratory findings is she most likely to have?

Decreased serum alpha-1-antitrypsin. AAT deficiency leads to lack of an anti-protease, which leads to development of emphysema, typically a panlobular type affecting lower lobes more severely, and by the 5th decade.

A 60-year-old woman develops multiple organ failure 3 weeks following a pneumonia complicated by septicemia. Antibiotic therapy has resulted in sputum and blood cultures that are now without growth of organisms. Nevertheless, she requires intubation with mechanical ventilation, but it becomes progressively more difficult to maintain her oxygen saturations. Ventilatory pressures must be increased. A portable chest radiograph shows increasing opacification of all lung fields. Which of the following pathologic processes is most likely now to be present in her lungs?

Diffuse alveolar damage. Diffuse alveolar damage (DAD) is the pathologic term for adult respiratory distress syndrome (ARDS) that is the final common pathway for many acute lung injuries. DAD produces increasing interstitial thickening with mixed inflammation and features of an acute restrictive lung disease.

A 20-year-old man falls to the ground while jogging. He suffers a minor abrasion to his left hand. However, within minutes he becomes dyspneic with right-sided chest pain. Bystanders call an ambulance. On arrival at the hospital, he has tachypnea and tachycardia. On physical examination breath sounds are absent over the right lung fields. A chest radiograph shows that the mediastinum is shifted to the left, and there are no fractures. A thoracentesis on the right yields a rush of air. Which of the following conditions is he most likely to have?

Distal acinar emphysema. Distal acinar (paraseptal) emphysema is not common, but does account for a significant number of cases of spontaneous pneumothorax in young persons. It is not related to smoking. There are subpleural bullae that can burst, even with minimal trauma. They may be multiple, accounting for recurrent episodes. However, the total amount of lung involved is minimal, so pulmonary function tests will be normal between episodes. He developed a tension pneumothorax in this case.

A 58-year-old man has been a smoker for 40 years. He has worsening orthopnea over the past year. On examination he has a body mass index of 35. He is afebrile. His blood pressure is 165/110 mm Hg. Auscultation of his chest reveals rales in lower lung fields bilaterally. A chest x-ray shows bilateral lower lobe infiltrates and a prominent left heart border. Laboratory studies show his Hgb A1C is 10%. Which of the following pulmonary problems is he most likely to have?

Edema. He has multiple risk factors for ischemic heart disease leading to left heart failure and pulmonary edema.

A 6-year-old child has the sudden onset of dyspnea with wheezing. On physical examination he is afebrile but has absent breath sounds on the right. His temperature is 37°C, pulse 82/minute, respiratory rate 32/minute, and blood pressure 100/60 mm Hg. An arterial blood gas measurement shows pO2 95 mm Hg, pCO2 25 mm Hg, and pH 7.55. Following administration of 100% FiO2 by nasal canula, a repeat measurement shows pO2 95 mm Hg, pCO2 25 mm Hg, and pH 7.55. Which of the following is the most likely diagnosis?

Foreign body aspiration. An inhaled object could obstruct a bronchus completely, with air resorbtion and collapse of lung distal to the point of obstruction. This produces a shunt defect with a V/Q mismatch. Since there is perfusion but no ventilation, even 100% oxygen will not make a difference. His hyperventilation has acutely produced an uncompensated respiratory alkalosis.

A newborn male infant develops increasing respiratory distress within an hour following an uncomplicated vaginal delivery at 36 weeks gestation. A plain film radiograph reveals near opacification of both lungs. Despite intubation and positive pressure ventilation, the baby dies within two days. At autopsy, the infant's lungs demonstrate extensive pink hyaline membranes. Which of the following maternal conditions is most likely to increase the risk for this infant's respiratory distress?

Gestational diabetes. The hyperinsulinism in the baby as a result of the high maternal glucose impedes development of the type II pneumonocytes. By 36 weeks there should normally be sufficient surfactant to prevent hyaline membrane disease. Tests for fetal lung maturity include lamellar body count on amniotic fluid, fluorescence polarization (fpol), phosphatidyl glycerol (PG), and L/S ratio.

A 51-year-old man complains of a slight cough he has had for a week. He is a non-smoker. On auscultation of the chest his lung fields are clear. A chest radiograph shows a subpleural 'coin lesion' 2 cm in diameter in the right upper lobe. Which of the following is the most likely diagnosis for this lesion?

Granuloma. The differential diagnosis of a solitary peripheral coin lesion most often includes lung cancer (adenocarcinoma most likely), granuloma, or hamartoma. Many people have had a remote, subclinical tubercular or fungal infection leaving only a solitary granuloma. In this case the cough suggests possible active infection, but it may just be an incidental, unrelated finding.

Following an acute pharyngitis lasting 4 days, a 10-year-old boy develops neck pain and marked halitosis. On physical examination is breath is very malodorous. A CT scan shows an abscess in the peritonsillar region. Laboratory studies include a culture of the abscess which grows anaerobic flora. Which of the following aerobic organisms is most likely to be cultured from his abscess?

Group A Streptococcus. A peritonsillar abscess is usually a complication of a 'strep' throat in a child.

A previously healthy 5-year-old girl develops a fever along with dyspnea. On physical examination her temperature is 37.9°C. Her lung fields are clear to auscultation but there are expiratory wheezes. A chest x-ray reveals clear lung fields. Laboratory studies show Hgb 13.6 g/dL, platelet count 183,600/microliter, and WBC count 14,480/microliter. Her dyspnea suddenly worsens, and emergent bronchoscopy reveals bronchi plugged by exudates. These findings are most consistent with infection by which of the following organisms?

Haemophilus influenzae. H. influenzae pneumonia can follow a descending laryngotracheobronchitis. The infection can cause airway obstruction from fibrin-rich exudates containing neutrophils, similar to pneumococcal pneumonia more common in adults. Pulmonary consolidation is usually bronchopneumonia and patchy but may involve the entire lung lobe. Vaccination is available for type b, but now non encapsulated and non-typeable forms are increasing in frequency.

A 23-year-old primigravida is found on prenatal testing to have an elevated hemoglobin A1C level. Her pregnancy is uncomplicated until the 33rd week of gestation, when she has the onset of premature labor and delivers a male infant 24 hours later. The infant initially has Apgar scores of 4 and 6 at 1 and 5 minutes, but within an hour is in severe respiratory distress and requires intubation with mechanical ventilation. Which of the following pharmacologic therapies administered to the mother prior to birth could have helped to prevent this infant's neonatal respiratory distress?

Hydrocortisone. She has diabetes, which inhibits fetal lung development. At 33 weeks, the baby's lungs may not make sufficient surfactant, though type II pneumomonocytes are present and increasing in number. Corticosteroids administered to the mother help to speed up type II pneumonocyte production of surfactant in the baby. At birth, exogenous surfactant can be given to the neonate. In addition, diabetes tends to impede fetal lung maturation.

A 66-year-old woman has had a worsening non-productive cough with malaise for the past week. Her temperature increases to 37.4°C. A chest radiograph reveals diffuse bilateral pulmonary interstitial infiltrates in all lung fields. A sputum gram stain reveals normal flora and few neutrophils. She recovers over the next two weeks without sequelae. Infection with which of the following organisms most likely caused her illness?

Influenza A virus. The typical appearance of a viral lung infection is interstitial inflammation. The inflammatory response is primarily T lymphocytes.

A 55-year-old man with a 50 pack year history of smoking cigarettes has recently experienced an episode of hemoptysis along with his usual cough. On physical examination he has no abnormal findings. A sputum for cytology on microscopic examination shows atypical cells with hyperchromatic nuclei and orange-pink cytoplasm. Labortory studies show a serum calcium of 11.3 mg/dL, with phosphorus 2.1 mg/dL. Which of the following chest radiographic findings is this man most likely to have?

Large hilar mass Both squamous cell and small cell carcinomas, most common in smokers, tend to be central in location. Squamous cell carcinomas of the lung are associated with hypercalcemia, though overall the small cell carcinomas are best known for paraneoplastic syndromes.

During a cardiac arrest, a 58-year-old man, a non-smoker, receives cardiopulmonary resuscitative measures and is brought to the hospital, where he is intubated. During the intubation procedure he suffers aspiration of gastric contents. Over the next 10 days he develops a non-productive cough along with a fever to 37.9°C. A chest radiograph reveals a 4 cm diameter mass with an air-fluid level in the right lung. A sputum gram stain reveals mixed flora. Which of the following conditions is he most likely to have?

Lung abscess. A Lung abscesses can result from aspiration of oropharyngeal or nasopharyageal contents, where bacterial organisms as part of normal flora can be transported to the lungs. The straighter bronchus to the right lung is more likely to conduct aspirated material. With septicemia, multiple abscesses are more likely to be present. The infection is often polymicrobial and difficult to treat.

A 65-year-old man has had no major medical problems prior to the past year, when he noted increasing malaise along with an 8 kg weight loss. He is a non-smoker. He currently does not have fever, cough, dyspnea, or any respiratory difficulties. On physical examination, he has non-tender supraclavicular lymphadenopathy. The lungs are clear to auscultation. A chest x-ray shows multiple solid nodules ranging from 1 to 3 cm scattered throughout all lung fields. No infiltrates or areas of consolidation are noted. Laboratory studies show Hgb 11.6 g/dL, Hct 34.7%, MCV 83 fL, and WBC count 6280/microliter. Which of the following pathologic processes in his lungs is most likely to account for these findings?

Metastatic carcinoma. Multiple persistent masses should suggest metastases, rather than a primary lung tumor. His lack of a cough or fever is against an infectious cause or aspiration.

A 30-year-old woman is in the 28th week of an uncomplicated pregnancy when she experiences the sudden onset of severe abdominal pain, followed by vaginal bleeding, then the onset of labor. A girl infant is delivered on the way to the hospital. On arrival within an hour, the baby is in respiratory distress and requires intubation and mechanical ventilation. A day later, a chest radiograph shows opacification of both lungs. The baby's respiratory status does not improve. Which of the following histopathologic findings is most likely to be present in this baby's lungs?

Minimal alveolar saccular development. The baby has been born prematurely, with incomplete lung development, and the lack of sufficient alveolar development along with minimal pulmonary surfactant production leads to hyaline membrane disease with respiratory distress in the newborn.

A 41-year-old man with a 6 kg weight loss over the past 3 months now has had worsening fever, non-productive cough, and dyspnea for the past 3 days. His temperature is 38.2°C and there are diffuse rales in both lungs on auscultation. A chest radiograph shows patchy infiltrates in both lungs. Laboratory studies show WBC count 3250/microliter with 81 segs, 3 bands, 5 lymphs, and 11 monos. His CD4 lymphocyte count is 79/microliter. Cryptosporidium parvum organisms are found in a stool specimen. A bronchoalveolar lavage is performed, yielding fluid that microscopically demonstrates pink, foamy exudate with little inflammation. Which of the following additional findings on microscopic examination is he most likely to have in the BAL specimen?

Multiple cysts with GMS stain. He is most likely to have Pneumocystis jiroveci pneumonia in association with the acquired immunodeficiency syndrome (AIDS). Note his lymphopenia from the very low CD4 count. PCP infection produces an exudate composed of the Pneumocystis cysts and trophozoites with little accompanying inflammation. The clinical findings in this case are typical as well.

An 11-year-old girl has experienced dyspnea for the past 2 weeks. Her temperature is 37.3°C, pulse 85/minute, respiratory rate 30/minute, and blood pressure 110/60 mm Hg. On physical examination, her lung fields are clear to auscultation. Her heart rate is regular and no murmurs or gallops are heard. A chest radiograph shows prominent hilar lymphadenopathy along with a 1 cm peripheral right middle lobe nodule. No infiltrates are present. A sputum gram stain shows normal flora and routine bacterial culture reveals no pathogens. Which of the following conditions is she most likely to have?

Mycobacterium tuberculosis infection. This is a description of the typical 'Ghon complex' of an initial, or primary, TB infection. The peripheral granuloma does not produce symptoms, but the enlarged lymph nodes may impinge upon airways. Most persons with a primary infection, however, are asymptomatic and the infection goes unnoticed.

A 38-year-old previously healthy woman has had a worsening non-productive cough for the past 4 days. On physical examination her temperature is 38.3°C. A chest radiograph shows patchy infiltrates and diffuse interstitial markings. Laboratory studies show a sputum gram stain with mixed flora. Her Hgb is 12.9 g/dL, platelet count 229,450/microliter, and WBC count 5815/microliter. Her cold agglutinin titer is elevated. Following a course of erythromycin therapy, she improves, with no complications. Which of the following infectious agents is the most likely cause for her pulmonary disease?

Mycoplasma pneumoniae. Mycoplasma infection predominantly affects the interstitium, and is not a widespread alveolar filling process. It is a cause for a 'primary atypical pneumonia' which is difficult to diagnose because this organism is not cultured by routine methods for bacterial organisms. The cold agglutinin titer is elevated in about half of cases and is a characteristic finding. Many cases respond to antibiotic therapy with erythromycin.

A 63-year-old woman has had increasing dyspnea for 5 years. On physical examination her lungs are hyper-resonant without dullness. Tactile vocal fremitus is slightly decreased over all lung fields. Scattered expiratory wheezes and inspiratory rhonchi are present without basal crackles. She has a chest radiograph that reveals increased lung volumes and flattening of the diaphragmatic leaves. Spirometry demonstrates an FEV1 that is decreased more than the FVC so that the FEV1/FVC ratio is less than 70% of normal. Which of the following inhaled substances, which increases the elaboration of neutrophil elastase, is most likely to cause her pulmonary disease?

Nicotine. She has findings of emphysema, and smoking is the most likely underlying cause. The nicotine in the cigarette smoke is chemotactic for neutrophils, and cigarette smoke activates the alternative complement pathway, releasing more mediators for neutrophil recruitment. Neutrophil elastase can damage the lung parenchyma. Though neutrophils are not numerous in the lung with emphysema, the cumulative effect of even small numbers of neutrophils over many years leads to the tissue damage.

A 51-year-old man received an orthotopic cardiac transplant a month ago. He has developed a fever with cough over the past 5 days. On physical examination his temperature is 37.5°C. A chest CT scan shows consolidation with abscess formation involving the left lower lobe. A sputum gram stain reveals normal upper respiratory tract flora. He does not respond to antibiotic therapy over the next 6 months. His mental status deteriorates and MR imaging of the brain shows multiple abscesses. He is most likely to have an infection with which of the following organisms?

Nocardia braziliensis. Nocardia braziliensis infection can persist and lead to chronic abscesses. It can complicate the course of immunocompromised patients. Though the lung is the portal of entry, dissemination to brain is common.

A 41-year-old woman has a 1 year history of episodic dyspnea. On physical examination there are expiratory wheezes. Her chest radiograph shows a few small 0.5 cm perihilar nodules. Laboratory studies show an elevated serum IgE along with peripheral blood eosinophilia. A sputum sample shows eosinophils. Which of the following pathologic findings is most likely present in her bronchi?

Non-invasive aspergillosis. She has an allergic bronchopulmonary aspergillosis. Her asthma is exacerbated by a type I hypersensitivity reaction to the fungus in the bronchi.

A study is performed reviewing medical records of adults presenting with sudden onset of severe dyspnea. They were afebrile, with absent breath sounds over an entire lung, and chest x-ray showing pulmonary atelectasis of an entire lung. Which of the following conditions is most likely to produce these findings?

Penetrating chest trauma. Penetrating chest trauma would lead to pneumothorax with lung collapse (atelectasis).

For the past 5 months, a 51-year-old woman has noted increased swelling of her lower legs as the day progresses. She has no fever and no cough. On physical examination, she has pitting edema to the knees. A chest radiograph reveals bilateral pleural effusions, and the right heart border is prominent. Laboratory studies show a serum AST of 238 U/L, ALT 263 U/L, LDH 710 U/L, and CK 127 U/L. Which of the following underlying diseases is most likely to cause these findings?

Recurrent thromboembolism. Pulmonary hypertension and subsequent right heart failure can occur in the small number of cases in which recurrent thromboembolism takes place. The right heart failure that occurs then leads to hepatic passive congestion with centrilobular necrosis that is the cause for the increased transaminases and LDH (but normal CK, since the heart is enlarged, but not ischemic).

A 50-year-old woman has lived in Oslo, Norway all her life and worked as a seamstress. She is a non-smoker, but she has had increasing shortness of breath, fever, weight loss, and night sweats for the past 4 months. On physical examination her temperature is 37.6°C. There are fine rales auscultated in all lung fields. A chest radiograph reveals hilar lymphadenopathy and a reticulonodular pattern of small densities in all lung fields. She demonstrates anergy by skin testing to mumps and Candida antigens. A transbronchial biopsy is performed that microscopically shows numerous small pulmonary interstitial non-caseating granulomas. Which of the following is the most likely diagnosis?

Sarcoidosis. Sarcoidosis is typified by non-caseating granulomas. However, culture of the tissue and a careful search histologically should be made for organisms before beginning therapy with corticosteroids. Extensive granulomatous disease can produce a restrictive pattern of pulmonary disease.

A 59-year-old man has been a cigarette smoker for the past 42 years. He has noted some blood-streaked sputum on coughing during the past week. He also has back pain. A chest radiograph shows a small 3 cm right hilar mass with several 1 to 2 cm peripheral lung nodules. A bone scan reveals multiple areas of increased uptake in the vertebrae, ribs, and pelvis. A sputum cytology reveals the presence of clusters of small cells having hyperchromatic nuclei and almost no cytoplasm. Which of the following laboratory test findings is he most likely to have as a consequence of his lung disease?

Serum sodium of 113 mmol/L. He has a small cell anaplastic carcinoma with widespread metastases. The syndrome of inappropriate ADH producing hyponatremia is one form of paraneoplastic syndrome seen with this particular carcinoma.

A 58-year-old man has developed a non-productive cough worsening over the past 2 months. Last week he noted the appearance of blood-streaked sputum. On physical examination there are some expiratory wheezes auscultated over the left lung. A chest radiograph reveals a 5 cm mass near the left lung hilum. A sputum cytology reveals the presence of small clusters of very hyperchromatic, pleomorphic cells with scant cytoplasm. Which of the following is the most likely predisposing factor to development of his pulmonary disease?

Smoking. Smoking remains the most frequent cause of lung cancer. Lung cancer does, however, occur in nonsmokers. A small cell anaplastic carcinoma, as in this patient, is virtually always seen in smokers. Small cell cancers arise in the central portion of the lung but are aggressive neoplasms that spread quickly.

At autopsy, a 60-year-old man is found to have a peripheral 7 cm area of golden-yellow consolidation on sectioning of the left lung. Microscopically, this area has alveoli filled with foamy macrophages. Which of the following conditions involving his lung is most likely to be responsible for this finding?

Squamous cell carcinoma. Most squamous cell carcinomas are located centrally and arise in bronchi, leading to obstruction of a large airway that can cause a distal lipid pneumonia. In this case, the breakdown of lung tissue distal to the mass yields an 'endogenous lipid pneumonia' with many macrophages. Some degree of atelectasis may also be present from air resorbtion distal to the obstruction.

A 40-year-old woman has had a high fever for a week, accompanied by a cough productive of yellowish sputum. On physical examination her temperature is 38.2°C. There are diffuse rales in all lung fields. Her chest radiograph reveals patchy infiltrates in all lung fields, and there is a 4 cm rounded area of consolidation in the left upper lobe that has an air-fluid level. Examination of her sputum reveals numerous neutrophils. Which of the following infectious agents is most likely causing her pulmonary disease?

Staphylococcus aureus. Pulmonary abscesses typically have an air-fluid level from liquefactive necrosis caused by the collection of neutrophils. More virulent bacterial organisms such as Staphylococcus aureus are likely to cause such a complication of a bronchopneumonia.

A 70-year-old woman at an extended care facility for the past two years has increasing inability to perform activities of daily living. She can no longer recognize family members. She is lethargic and spends most of her days in a wheelchair or in bed. She develops an acute febrile illness and is noted to be coughing up increasing quantities of yellowish sputum. Her temperature is 38°C. A chest x-ray shows infiltrates involving the left lower lobe. A sputum sample shows numerous neutrophils and gram-positive diplococci. Which of the following infectious agents is most likely to cause her pulmonary disease?

Streptococcus pneumoniae. She has a lobar pneumonia, which is most often a community aquired pneumonia (the nursing home counts as a community venue), following a debilitating course of Alzheimer disease. The most common organism is Streptococcus pneumoniae (pneumococcus).

A 70-year-old woman has been bedridden for 5 weeks following a cerebrovascular accident (CVA). She has the sudden onset of dyspnea, but has no further symptoms until two days later when she experiences left sided pleuritic chest pain. A radiologic imaging study show a wedge-shaped area consistent with hemorrhage based on the pleura of the left lower lobe. Which of the following pathologic findings in her pulmonary arterial branches is she most likely to have?

Thromboembolism. An embolus to a medium-sized arterial branch may not be large enough to kill the patient, but large enough to cause an infarction. Her bedridden state predisposes her to deep venous thrombosis and thromboembolism--the CVAs are due to separate systemic arterial problems--or the systemic and pulmonary embolization can be tied together by a hypercoagulable state, or more remotely by a 'paradoxical' embolus through a patent foramen ovale once the right sided-pressures increased following the initial pulmonary thromboembolic event.

On the 11th postoperative day following a radical prostatectomy for adenocarcinoma, a 70-year-old man is recovering uneventfully. He then ambulates to the bathroom, but upon returning to his bed he suddenly becomes extremely dyspneic and diaphoretic, with chest pain, palpitations, and a feeling of panic. Which of the following post-operative pulmonary complications has he most likely developed?

Thromboembolus. The activity of ambulation resulted in embolization of a thrombus that formed during his period of immobilization in leg or pelvic veins. The thrombus became an embolus and traveled up the vena cava, through the right heart, and to the pulmonary arterial tree of the lungs.