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Radiological Diagnosis

Chest

The radiological appearance of the pulmonary infection in the majority of these patients will be that of tuberculosis or one of the other granulomatous diseases. The most frequent pattern noted on chest roentgenograms in the acute group consists of generalized, irregular, small nodular densities which may rapidly enlarge, coalesce, or cavitate (Figs. 23.6 & 23.7). The nodules range from 4 to 10 mm in size and the pattern may resemble disseminated tuberculosis, fungal disease, or staphylococcal pneumonia. In some patients, the nodules coalesce and there is segmental or lobar consolidation in one or multiple lobes; this usually happens in one lung and the same patient may show both a lobar infiltrate and a generalized nodular pattern (Figs. 23.8 - 23.11). Melioidosis, whether acute or chronic, has the same predilection for the upper lobes as does tuberculosis. Pleural involvement with effusion and empyema occasionally occurs (Fig. 23.8). Hilar adenopathy is rare, a very useful differential finding (Fig. 23.6C).

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Fig. 23.6 Acute septicemic melioidosis with disseminated small pulmonary abscesses producing a fine nodular pattern in the lungs of three patients, all of whom were American soldiers serving in South Vietnam when they contracted their disease. This form of the disease is highly fatal and, indeed, all three of these previously healthy young men died within days of onset of their disease. A This soldier presented with a 3-5 day history of chills, fever of 38°- 40°C, malaise, fatigue and productive cough. Physical examination revealed bilateral rales and rhonchi. Chest x-ray showed disseminated small, irregular, nodular densities throughout both lungs, representing multiple small abscesses caused by B. pseudomallei, which was isolated from the patient. He died shortly after admission. B Another soldier with similar small nodular densities scattered throughout both lungs. In the right lung, there are surrounding small patches of pneumonitis associated with these small abscesses. (Courtesy of Dr. Douglas Sheft, San Francisco.) C Another American soldier who became acutely ill with fever of 38°- 40°C (102°- 104°F) of 3-5 days duration accompanied by chills, malaise, fatigue and cough productive of small quantities of grayish-white or yellow-green sputum. Rales and rhonchi were heard on auscultation. Chest x-ray demonstrated right hilar adenopathy and bilateral diffuse nodular densities representing small abscesses throughout the lungs. He died shortly after admission. This is the only patient in the series who showed hilar adenopathy. Mediastinal and hilar adenopathy are most unusual in the acute phase of the disease, since the infectious process moves so rapidly with fatal termination within days unless massive antibiotic therapy is instituted promptly. It is possible this patient's hilar lymphadenopathy may have been present prior to the onset of melioidosis and caused by some other etiology. (A,C courtesy of Dr. A.E. James et al: pulmonary abscess in a fatal case of acute melioidosis. AFIP 69-5776 and Radiology, 1967) D Tiny discrete pulmonary abscess in a fatal case of acute melioidosis. AFIP 69-5776.

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Fig. 23.7 A,B Acute septicemic melioidosis with fatal outcome in a 22-year-old white male American soldier. The patient had just returned to the U.S. from 9 months duty in Vietnam on October 4, 1966. Two days later, he developed sore throat and fever, unresponsive to antibiotic therapy. Fever, headaches, chest and left upper quadrant abdominal pain, and productive cough led to hospital admission on October 15 with a diagnosis of viral pneumonia and treatment with antibiotics. His illness progressed rapidly and he died on October 28. Hepatomegaly and splenomegaly were noted terminally. He had received a minor injury from a punji stick (a pointed stick contaminated with fecal debris and organisms and placed in the ground-a primitive weapon used during the Vietnam conflict). A Posteroanterior (PA) chest film obtained on October 23 shows a few small nodules in the left midlung and minimal patchy infiltrate at the right costophrenic angle and right suprahilar area. B PA chest film taken on October 28 shortly before death shows rapid progression of the disease with a marked bilateral hazy nodular infiltrate representing disseminated small pulmonary abscesses and surrounding zones of pneumonitis. At autopsy, small abscesses 1 mm to 4 cm in diameter were found throughout the lungs and in the thoracic lymph nodes, pleura, liver, spleen, bone marrow and right adrenal gland. Gram- negative, pleomorphic, bipolar staining bacilli were present and culture revealed B. pseudomallei. The tracheobronchial tree contained a marked amount of frothy, blood-tinged pulmonary edema fluid, but no ulcerations or purulent material. Throughout all lobes there were slightly raised, fairly well circumscribed, yellow-gray nodules 1 mm to 2-4 cm in diameter, the largest abscess being in the left lower lobe posteriorly. These nodules were predominantly firm, but several showed central cavitation with the cavities filled with creamy, yellow-green purulent material; no caseous changes were noted. Microscopically, there was a focal fibrinous pleuritis, marked pulmonary edema and congestion, and diffuse abscesses. An inflammatory infiltrate contained neutrophiles, lymphocytes and macrophages. There was a striking cellular lysis within the abscesses. C-E Photomicrographs of histological changes in the lungs and liver of another fatal case of melioidosis. C Interstitial pneumonitis with filling of the alveoli by a fibrino-sero-cellular exudate. D The edge of a caseo-necrotic nodule in the lung. E Gram-negative, pleomorphic bacilli, many of which are intracytoplasmic, in the liver.

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Fig. 23.8 A-C Acute melioidosis with fatal outcome in three American soldiers who contracted the disease while serving in South Vietnam. A This patient presented with a 3- 5-day history of chills, fever, malaise, fatigue and productive cough. He was acutely ill with a fever of 38°- 40°C (102°- 104°F) with rales and rhonchi throughout both lungs. He expired shortly after admission from disseminated melioidosis proven bacteriologically. Chest x-ray on admission showed ill defined areas of consolidation in the right upper lobe and several patchy infiltrates scattered throughout the left lung. B Another soldier with a similar history and physical findings who likewise expired from septicemic melioidosis shortly after admission. Chest x-ray shows patchy, confluent consolidation of the left upper lobe with slight associated pleural reaction. Pleural reaction and fluid or empyema may occasionally be seen in acute melioidosis. (A, B Courtesy of Dr. A. E. James et al. and Radiology, 1967) C Another soldier who died with acute congestive heart failure superimposed on melioidosis. Chest radiograph shows patchy, bilateral pulmonary infiltrates and a large right pleural effusion. There is moderate pulmonary vascular congestion and slight cardiomegaly. The pleural effusion is more likely from congestive failure than the underlying melioidosis, although pleural fluid can accumulate in the acute phase of the disease. D Histological section of the lung from another fatal case of melioidosis, showing consolidation and gray hepatization.

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Fig. 23.9 A-D Acute melioidosis in a 34-year-old American black male soldier who recovered from his disease after massive antibiotic therapy. He was admitted to a military hospital in Vietnam with a 3-day history of chills, fever, malaise and fatigue. He had a brief illness 2-3 weeks earlier with a mild cough productive of small amounts of yellow-green sputum. He had a fever of 38°C (102°F) and tubular breath sounds over the right apex. A Initial PA and B apical lordotic views of the chest showed mottled, irregular, nodular densities in the right upper lobe with patchy areas of consolidation. Initial treatment consisted of 20 million units of intravenous penicillin and 1.5g of chloramphenicol orally for 3 days. The patient became afebrile, but chest radiographs showed progression of the disease. Bacteriological examination revealed B. pseudomallei and antibiotic therapy was modified to include 2 gm of chloramphenicol and 1 gm of novobiocin every 6 hours with intravenous fluids, and 1 gm of kanamycin every 6 hours intramuscularly. The patient continued to improve clinically and follow-up PA (C) and apical lordotic (D) chest films taken 9 days after the initial films showed improvement with considerable clearing of the patchy areas of consolidation. There were still residual small mottled densities in the right upper lobe. The patient continued on oral chloramphenicol and novobiocin and eventually became asymptomatic. ( Courtesy of Dr. A. E. James et al. and Radiology, 1967).

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Fig. 23.10 A-D Acute melioidosis in two American soldiers serving in Vietnam, both of whom recovered after intensive antibiotic therapy, as well as a postpartum Vietnamese woman with sepsis. A PA and B lateral chest films of the first soldier show extensive patchy consolidation and infiltrate in the right upper lobe. Subsequent films showed eventual clearing of this infiltrate after massive antibiotic treatment. C PA chest film shows scattered soft pulmonary infiltrates with air bronchograms and multiple tiny nodular densities in both lungs, especially in the right upper lobe. This patient was a 24-year-old black male soldier who developed fever, chills, night sweats and a cough productive of yellow sputum from which B. pseudomallei was cultured. Complement fixation test showed a titer of 1:32, and hemagglutination test a titer of 1:20. Initial treatment was with chloramphenicol, kanamycin and novobiocin followed by 2 months of tetracycline, with eventual clearing of the infiltrates. D Vietnamese woman who was febrile and toxic with sepsis 3 weeks postpartum. Numerous cavitating septic emboli are present throughout both lungs. Blood culture was positive for B. pseudomallei. (D from P. Cockshott and H. Middlemiss: Clinical Radiology in the Tropics. Churchill Livingstone, Edinburgh, 1979).

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Fig. 23.11 A-D Resolution of left upper lobe infiltrate in acute melioidosis after prolonged intensive antibiotic therapy. The patient was a 21-year-old American black male soldier admitted to a military hospital in Vietnam on August 20, 1966, with a 3 day history of pleuritic chest pain, anorexia, nausea, fever, and cough productive of grayish-white sputum. There was a small white pustule on his right anterior tonsilar pillar, and rales and rhonchi were heard at the apex of the left lung. A PA chest film of August 26 shows extensive small irregular nodular densities in the left upper and midlung fields from multiple small abscesses. There is an area of cavitation in the left apex beneath the clavicle. B A lateral chest film of August 28 shows coalescence of these small patchy densities to form a confluent area of consolidation and pneumonitis in the posterior apical segment of the left upper lobe. C Apical lordotic view taken on August 30 shows the patchy, confluent infiltrate throughout much of the left upper lobe as well as the cavity at the left apex. There is also minimal pleural fluid along the left lateral chest wall and costophrenic angle. (Cavitation within the lung and pleural fluid may occasionally be seen in acute melioidosis.) D Follow-up PA chest film of September 3 shows partial clearing of the small nodular densities and patchy infiltrate, and a final chest film of September 17 showed virtually complete clearing of the pneumonitis and small abscesses in the left upper lobe. Cultures from both sputum and throat were positive for B. pseudomallei. The patient was initially treated with chloramphenicol (12 gm per day intravenously), novobiocin (2 gm per day intravenously) and kanamycin (4 gm per day intramuscularly). The chloramphenicol and kanamycin were reduced by one-half on the 8th treatment day and the kanamycin was discontinued 4 days later. The patient became afebrile and was asymptomatic at the time of his final chest film. (Courtesy of Dr. A. E. James et al and Radiology, 1967).

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