British Journal of Radiology 74 (2001),955-958 © 2001 The British Institute of Radiology
Calcification in invasive tracheal aspergillosis demonstrated on ultrasound: a new finding
A E Drury, FRCR1,
R A Allan, MSc, FRCR1,
H Underhill, DM, MRCPCH2,
S Ball, DM, FRCPCH2 and
A E A Joseph, MSc, FRCR1
Departments of 1Radiology and 2Paediatrics, St George's Hospital NHS Trust, Blackshaw Road, London SW17 0QT, UK
Correspondence: Dr R A Allan
 |
Abstract
|
|---|
Invasion of the major airways is a rare manifestation of respiratory tract involvement by Aspergillus sp. and is seen almost exclusively in immunocompromised patients. We present calcification as a new feature of this condition and its demonstration by ultrasound in a 15-year-old boy with severe neutropenia secondary to aplastic anaemia.
|
Introduction
|
|---|
Invasive aspergillosis is the most common fungal infection in immunocompromised patients and involves the respiratory tract in 90% of cases [1]. It is frequently rapidly fatal if unrecognized and not treated. The most common form of invasive respiratory aspergillosis is a necrotizing pneumonitis with local angioinvasion, but a rarer airway-invasive form is also recognized. One previous case report has described the radiographic and CT findings of invasive tracheal aspergillosis [2], and a second has described the radiological features of major bronchus disease [3]. As far as we are aware, this is the first report both of calcification in this condition and of the ultrasound features of the disease.
|
Case history
|
|---|
A 15-year-old boy with profound neutropenia secondary to long-standing aplastic anaemia, which was refractory to immunosuppressive therapy, presented with a 4-day history of sore throat and pyrexia. Initial investigations, including a chest radiograph, showed no underlying cause. He was assumed to have a febrile neutropenic episode and was treated with iv antibiotics. Despite some initial improvement, he developed a progressive productive cough with haemoptysis and retrosternal chest pain together with persistence of his sore throat and pyrexia. ENT examination showed oedema of the false cords but normal and mobile vocal cords.
A repeat chest radiograph showed that, although the lungs remained clear, there was subtle circumferential tracheal narrowing, which was confirmed on a lateral radiograph of the soft tissues of the neck. Contrast enhanced CT (Figure 1
) confirmed the presence of a homogeneous soft tissue mass encircling and narrowing the trachea and splaying the lobes of the thyroid. This mass was thought to be either inflammatory or malignant in nature. Amphotericin B was added empirically to the broad spectrum antibiotic treatment. Ultrasound examination demonstrated a soft tissue mass anterior to the trachea and extending from the thyroid to the suprasternal notch. The mass contained multiple foci of increased echogenicity and was disrupting the tracheal cartilagenous rings. Although the degree of cartilage destruction was initially thought to favour malignancy, fine needle aspiration performed under ultrasound guidance yielded Aspergillus hyphae. He was therefore continued on full dose iv amphotericin, but remained profoundly neutropenic.
View larger version (135K):
[in this window]
[in a new window]
|
Figure 1. Contrast enhanced CT demonstrating a circumferential homogeneous soft tissue mass (arrowheads) with tracheal narrowing and lateral displacement of the lobes of the thyroid.
|
|
Serial ultrasound examinations were performed over 7 weeks. At 2 weeks some of the echogenic foci were thought to represent air within fistulae (Figures 2a,b) and by 4 weeks areas of calcification were seen within the mass (Figures 3a,b). A second CT (Figure 4) confirmed persistent narrowing of the trachea by the residual soft tissue mass and an outer irregular, almost circumferential cuff of calcification. Multiple air pockets, presumed fistulae, were present within the mass.
View larger version (74K):
[in this window]
[in a new window]
|
Figure 2. (a) Longitudinal and (b) axial ultrasound examinations of the neck demonstrating the circumferential tracheal soft tissue mass (large arrows). Several echogenic foci are seen within the mass, some of which appear to be in an air-containing fistula arising from the tracheal lumen (small arrows).
|
|
View larger version (57K):
[in this window]
[in a new window]
|
Figure 3. (a) Longitudinal and (b) axial ultrasound examinations of the neck at 4 weeks. Calcification has developed around the trachea (curved arrows).
|
|
View larger version (141K):
[in this window]
[in a new window]
|
Figure 4. Contrast enhanced CT confirming an outer cuff of calcification, with multiple air pockets within the residual soft tissue mass. The tracheal lumen (T) remains narrowed.
|
|
Shortly after this second CT the patient developed acute severe biphasic stridor and upper respiratory tract obstruction, for which he was intubated and ventilated prior to a tracheostomy. He succumbed to complications of bone marrow transplantation 3 months later.
|
Discussion
|
|---|
Inhalation of airborne spores of Aspergillus sp. results in colonization of respiratory surfaces, the type of disease caused being determined by the host's immunological status. Allergic bronchopulmonary aspergillosis occurs in atopic individuals, whereas immunocompromized neutropenic patients are at risk of invasive aspergillosis that may be rapidly fatal. The major risk factor for developing invasive aspergillosis is neutropenia lasting more than 3 weeks, usually as a result of haematological malignancy, chemotherapy, treatment with immunosuppressives or AIDS [4, 5], because neutrophils and tissue macrophages are the main host defences against fungal infection.
The form of respiratory tract disease caused by Aspergillus sp. relates to the site of local invasion, with the commonest manifestation being a necrotizing angioinvasive pneumonitis. Other presentations include local invasion of peripheral airways with spread to adjacent lung parenchyma, local invasion of main airways and sinus disease. Aspergillosis affecting the airways as the major or only feature of invasive disease is uncommon, occurring in 7% of cases of intrathoracic aspergillosis [6]. The first reports of tracheal disease were from autopsy studies, with invasion through the tracheobronchial tree without accompanying bronchopneumonia found in only 0.5–1% of patients who died of aspergillosis [1, 7].
It is not clear why disease is confined to the tracheobronchial tree in some patients who develop invasive aspergillosis. It has been suggested that this occurs when the degree of immunosuppression is less profound [6, 7] or the degree of neutropenia transient or milder. Local defence mechanisms may also play a role, as infection occurs more commonly at the site of surgical anastomosis after heart/lung transplantation [8] and the prolonged presence of an endotracheal tube is a risk factor [6]. However, both our patient and the patient previously reported with invasive tracheal aspergillosis [2] were profoundly neutropenic and neither had had prior intervention of their proximal airways.
Two morphological forms of invasive aspergillosis of the trachea and bronchi have been described [6]. There is either an intraluminal, circumferential and superficial "pseudomembrane" of necrotic tissue, fibrin and hyphae, which may result in airway occlusion; or multiple nodular plaques that invade adjacent tissues and may result in broncho-oesophageal and fatal haemorrhage from bronchoarterial fistula [9, 10]. The plaques can be impossible to remove because they may be extensive and because of mucosal haemorrhage [11], the risk of which can be increased by bronchoscopy. In our patient, percutaneous ultrasound guided aspiration of material for histology avoided the risk of a diagnostic bronchoscopy.
There is little documentation of the radiological features of invasive aspergillosis of the trachea alone in the literature. In a series of nine patients, who had disease of the peripheral airways with local pulmonary invasion [12], two had histological evidence of additional tracheal or main stem bronchus involvement. Although CT demonstrated the peripheral airways disease as peribronchial consolidation in these cases, it failed to detect invasion of the trachea and main stem bronchi. However, CT can demonstrate main airway invasion [13]. In a similar case to that presented here, chest radiography demonstrated a right paratracheal density, with tracheal narrowing and circumferential paratracheal soft tissue visible on CT, in a 16-year-old patient with disease confined to the trachea [2].
In the present case, we were better able to visualize thickening of the tracheal wall, fistulation and cartilage destruction with ultrasound than with CT which, to our knowledge, has not been described before. This is also, as far as we are aware, the first description of healing with calcification in this condition, although calcification is known to occur in aspergillosis of the paranasal sinuses [13].
Received for publication January 8, 2001.
Revision received May 31, 2001.
Accepted for publication June 19, 2001.
|
References
|
|---|
-
Meyer RD, Rosen P, Armstrong D, Yu B. Aspergillosis complicating neoplastic disease. Am J Med 1973;54:6–15.[Medline]
-
Vail CM, Chiles C. Invasive pulmonary aspergillosis: radiologic evidence of tracheal involvement. Radiology 1987;165:745–6.[Abstract/Free Full Text]
-
Ahn MI, Park SH, Kim JA, Kwon MS, Park YH. Pseudomembranous necrotizing bronchial apsergillosis. Br J Radiol 2000;73:73–5.[Abstract]
-
Gerson SL, Talbot GH, Hurwitz S, Strom BL, Lusk E, Cassileth PA. Prolonged granulocytopenia: the major risk factor for invasive pulmonary aspergillosis in patients with acute leukaemia. Ann Intern Med 1984;100:345–51.
-
Kemper CA, Hostetler JS, Follansbee SE, Ruane R, Covington DC, Leong S, et al. Ulcerative and plaque-like tracheobronchitis due to infection with Aspergillus in patients with AIDS. Clin Infect Dis 1993;17:344–52.[Medline]
-
Clark A, Skelton J, Fraser RS. Fungal tracheobronchitis: Report of 9 cases and review of the literature. Medicine 1981;70:1–14.
-
Young RC, Bennet JE, Vogel CL, Carbonne PP, Stanford W, DeVita VT. Aspergillosis: the spectrum of disease in 98 patients. Medicine 1970;49:147–73.[Medline]
-
Kramer MR, Denning DW, Marshall SE, Ross DJ, Berry G, Lewiston NJ, et al. Ulcerative tracheobronchitis after lung transplantation. A new form of invasive aspergillosis. Am Rev Respir Dis 1991;144:552–6.[Medline]
-
Mineur P, Ferrant A, Wallon J, Otte JB, Michaux JL. Bronchooesophageal fistual caused by pulmonary apsergillosis. Eur J Respir Dis 1985;66:360–6.[Medline]
-
Berlinger NT, Freeman TJ. Acute airway obstruction due to necrotizing tracheobronchial aspergillosis in immunocompromised patients: a new clinical entity. Ann Otol Rhinol Laryngol 1998;98:718–20.
-
Hines DW, Meryl HH, Yaremko L, Britton C, McLawhon RW, Harris AA. Pseudomembranous tracheobronchitis caused by Aspergillus. Am Rev Respir Dis 1991;143:1408–11.[Medline]
-
Logan PM, Primack SL, Miller RR, Muller NL. Invasive aspergillosis of the airways: radiographic, CT and pathologic findings. Radiology 1994;193:383–8.[Abstract/Free Full Text]
-
Patel PJ, Kolawole TM, Malabarey TM, Hulailah FH, Chakaki M. CT findings in paranasal aspergillosis. Clin Radiol 1992;45:319–21.[Medline]
Top
Abstract
Introduction
