untitled REVIEW ARTICLE 4 SA JOURNAL OF RADIOLOGY • December 2005 Abstract Actinomycosis is a chronic infection caused by Gram-positive anaerobic bacteria which is found worldwide. Common features of actinomycosis infections include abscess formation, granulation, dense fibrous tis- sue formation, and the classical cutaneous sinuses with yellow/sulphur granular dis- charge. However some of the features may be nonspecific and the absence of classical features may delay the diagnosis. Since actinomycosis responds well to various antibiotic treatments, with or without sur- gical intervention it is worthwhile includ- ing actinomycosis infection in the differen- tial diagnosis. We present radiological findings for 4 patients presenting with different forms of thoracic and abdominopelvic actinomyco- sis infection, and a short review of the doc- umented literature findings. Introduction Actinomycosis is a chronic infection caused by Gram-positive anaerobic bacte- ria, with the usual pathogen in man being Actinomycosis israelii, accounting for 85% of human infections.1,2 Actinomycosis is found worldwide and may affect any age group.1,3,4 This pathogen is normally found in the oral cavity and gastrointestinal tract (GIT) of healthy individuals. When the protective barriers are broken, opportunis- tic infection develops by direct extension, for example after dental manipulation. Infection may also develop by aspiration of oropharyngeal contents or gastrointestinal secretions causing respiratory tract infection, or may develop in association with foreign bodies such as intrau- terine contraceptive devices (IUCDs) causing abdominopelvic acinomycosis.1,2,5 Haematogenous dissemination from a pre- existing focus is rare, but may occur from thoracic disease.1,2,4 The chronic progressive suppurative infection caused by actinomy- cosis organisms has shown three major sites of predilection being cervicofacial (55% mean frequency),3 abdominopelvic (25%), and thoracic (15%).5 Common features of actinomycosis infections include abscess formation, gran- ulation, dense fibrous tissue formation, and the classical cutaneous sinuses with ‘yellow sulphur’ granular discharge. Cavitations may be noted in lung involvement which may develop sinuses to the skin. Fistula formations are seen in GIT infections, and permeative bone destruction is seen with osseous involvement. However some of the features may be nonspecific and the absence of classical features may delay the diagnosis.1 Actinomycosis infection responds well to antibiotic treatment, traditionally intra- venous Penicillin G for 4 - 6 weeks being the treatment of choice, followed by oral penicillin for 6 - 12 months.1 However ery- thromycin, tetracycline, cephalosporins and other antibiotics, alone or in combina- tion, may also be used successfully.1,2,4,5 The duration of treatment may need to be tai- lored to the individual. A combined med- ical-surgical approach may be required. Surgical intervention assists in recovery but is not usually curative on its own.2 We present the radiological findings for 4 patients presenting with different forms of actinomycosis infection and give a short review of the relevant literature. Thoracic actinomy- cosis Case 1 A 63-year-old woman presented with chronic cough and chest pain. A small sinus was found on the skin adjacent to the sternum on the left which was not draining at the time of examination. Chest X-ray demonstrated an ill- defined mass adjacent to the aorta on the left, associated with left upper lobe fibrosis. An area of sub-segmental atelectasis was seen in the right lower lobe. This was thought not to be significant (Fig. 1). A post-contrast CT scan of the chest demonstrated an irregular inhomogeneous soft-tissue mass in the left upper lobe adja- cent to the aorta extending to the anterior thoracic wall lateral to the left edge of the sternum. The degree of contrast enhance- ment was negligible (Figs 2a and b). The differential diagnosis included tuberculosis, neoplasm, or actinomycosis. An open lung biopsy was performed and the histology demonstrated sclerotic lung changes with interstitial fibrosis, and a filamentous bacterium, namely actinomy- cosis, was isolated. Case 2 An adult male patient presented with swollen painful knees and a history of chronic cough. Chest X-ray demonstrated an irregular right upper lobe mass associat- Thoracic and abdominopelvic actinomycosis K Spiegel MB BCh, FCRad (Diag) E Joseph MB BCh, FFRad (Diag) Helen Joseph Hospital Auckland Park Johannesburg Fig. 1. Erect chest X-ray demonstrating opacification in the left upper lobe adjacent to the mediastinum (arrow). 7 11/25/05 1:49 PM Page 4 ed with right upper-lobe volume loss and elevation of the right hilum as well as right parattracheal fullness (Figs 3a and b). Contrast-enhanced CT scan of the chest confirmed the presence of the irregular right upper lobe posterior segment inho- mogeneous lobulated mass with associated pleural reaction but no rib erosion. Extension into the mediastinum was demonstrated with a hypodense mass seen in the right paratracheal region which was splaying and displacing the major vessels. No significant contrast enhancement was demonstrated (Figs 4a and b). Plain X-ray of the knees demonstrated bilateral distal femoral and proximal tibial and fibular periosteal reactions bilaterally which were diagnosed as hypertrophic osteoarthropathy (Fig. 5). The differential diagnosis in this case included right upper lobe neoplasm with mediastinal lymph node involvement, or a chronic infection with involvement of mediastinal lymph nodes, such as thoracic actinomycosis. Sputum analysis confirmed the diagnosis of actinomycosis. Abdominopelvic actinomycosis Case 3 A 42-year-old man presented with a palpable lesion in the right hypocondrium. Chest X-ray demonstrated an elevation of the right hemi-diaphragm. There were no focal lung parenchymal lesions (Fig. 6). Contrast-enhanced CT scan of the chest demonstrated a subcutaneous abscess with communication to the pericapsular region of the liver extending through the anterior lower right chest wall. The lesion showed contrast rim enhancement. No focal pathology was demonstrated in the liver (Figs 7a and b ). This infection was patho- logically proven to be actinomycosis and the patient duly responded to IV penicillin treatment. REVIEW ARTICLE 5 SA JOURNAL OF RADIOLOGY • December 2005 Figs 2a and b. Axial post-contrast CT scan of the chest demonstrating a left para-aor- tic mass extending to the anterior thoracic wall (arrow). 2A 2B Figs 3a and b. PA erect and lordotic (apical view) chest X-ray demonstrating the right upper lobe opacity in the right paratracheal region (arrow). 3A 3B Figs 4a and b. Axial non-enhanced CT scan of the chest demonstrating a lesion in the right upper lobe posterior segment (arrow) and an inhomogeneous hypo- dense lesion (arrow head) in the upper mediastinum. 4A 4B Fig. 5. AP X-ray of the knees demonstrat- ing bilateral periostial reactions involving the femora, tibiae and fibulae. Fig. 6. Erect PA chest X-ray demonstrating an apparent elevation of the right hemi- diaphragm. 7 11/25/05 1:49 PM Page 5 Case 4 A 39-year-old woman presented with a pelvic mass. She had had an IUCD in situ for several years. A contrast-enhanced CT scan of the abdomen demonstrated an inhomoge- neous irregular pelvic mass involving the uterus with infiltration of the surrounding mesentery and multiple associated abscess- es. Extension to the right anterior lower abdominal wall with abscess formation through the lower abdominal wall was shown, but with no breakthrough to the skin. The adjacent bowel wall was thick- ened (Figs 8a-d). This was confirmed as actinomycosis and the patient responded well to treat- ment with penicillin. Discussion Thoracic actinomycosis Thoracic actinomycosis is a rare disease that may mimic other pathology such as tuberculosis and primary or metastatic lung cancer.1,4 Actinomycosis may also coexist with these pathologies.2-4 Infection of the lung, pleura, mediastinum or chest wall may be caused by direct extension from cervicofacial infection, an oesophageal tear, by inhalation or aspira- tion and rarely by haematogenous spread from a distant focus.2 The radiological features include localised ill-defined lung infiltrate, air space consolidation, or a mass lesion, with or without associated cavitation.2,4 A pul- monary infiltrate with a basal predomi- nance and involvement of adjacent lobes through interlobar fissures is said to be sug- gestive of thoracic actinomycosis.1,4 The pathology may extend to the mediastinum, pericardium, myocardium, and preverte- bral space with vertebral body involvement. Extension to the skin surface with sinus tract formation may also be present,2 as demonstrated in case 1 (figs 1 and 2). Pleural involvement includes both pleural thickening and pleural effusion.1,6 The presence of a chronic pleural effusion with underlying lung changes and periosteal rib involvement is usually accepted as a diag- nostic triad. Unfortunately Sumoza et al.4 found this to be the exception rather then the rule. Table I lists the common and less common features of thoracic actinomyco- sis. Not all features may be demonstrated by actinomycosis infection and in the absence of the classic cutaneous fistulas with yellow granular discharge the diagno- sis may be delayed.1 Hypertrophic osteoarthropathy Hypertrophic osteoarthropathy (HOA) is characterised by periostosis of the tubu- lar bones and digital clubbing. In the pri- mary form no underlying cause is found, but when an underlying disease is present this syndrome is referred to as secondary 6 SA JOURNAL OF RADIOLOGY • December 2005 Figs 7a and b. Axial post-contrast CT scan of the upper abdomen demonstrating a right upper-quadrant rim-enhancing collec- tion over the right lobe of the liver anterior- ly. Extension to the subcutaneous tissue in a collar stud appearance is demonstrated in Fig. 7a.(arrow). 7A 7`B 8A 8C 8B 8D Figs 8a-d. Axial post-contrast CT scan of the pelvis demonstrating an inhomoge- neously enhancing central pelvic mass iin- volving the uterus, with solid and liquid components representing multiple abscesses (small arrows) as well as infil- tration of the surrounding mesentery and adjacent bowel wall thickening. Figs c-d also demonstrate involvement of the right anterior lower abdominal wall with abscess formation (large arrows). Table I. Radiological features of thoracic actinomycosis 1. Infiltrative changes suggestive of aspiration pneumonitis or consoli- dation extending across interlobar fissures. 2. Fibronodular or cavitary parenchy- mal disease . 3. An intraparenchymal mass. 4. Pleural effusion or empyema (rare). 5. Involvement of chest wall soft tissue and destruction of adjacent bone with formation of sinus tracts to the skin. 6. Involvement of the mediastinum, pericardium, myocardium. Rarely, superior vena caval obstruction and oesophageal fistula formation. 7. Thoracic vertebral destruction with preservation of disk space height. 8. Hypertrophic osteoarthropathy. REVIEW ARTICLE 7 11/25/05 1:49 PM Page 6 HOA. Many underlying pathologies may be associated with HOA such as intratho- racic malignancy or infection, pleural pathology, cyanotic cardiac pathology, intestinal pathology, and more. The associ- ation of digital clubbing and HOA with chronic pulmonary disease was recognised in the late 1800s.7,8 In a review of the liter- ature no reports of HOA with actinomyco- sis was found. Since thoracic actinomyco- sis is considered a chronic infection associ- ated with cavitation, fibrosis and pleural involvement it falls under chronic pul- monary disease and therefore, as in our sec- ond case (case 2), it is assumed that it may be associated with HOA on this basis. Abdominopelvic actinomy- cosis Abdominal actinomycosis usually occurs following penetrating trauma, per- foration of a hollow viscus (e.g. appendix) or surgical manipulation 9,10 There is a predilection for the ileocaecal region where it may be confused with caecal tuberculosis, amoeboma, chronic appendicitis, and car- cinoma of the caecum.2,3 Primary pelvic actinomycosis may occur in association with IUCD colonisation and infection and is more likely with prolonged use of an IUCD, as demonstrated in case 4.3,11 Pelvic actinomycosis is also known to occur in association with septic abortion, retained sutures from previous surgery, or spread from an intra-abdominal focus. Abdominopelvic actinomycosis may present as an aggressive-looking mass.3,5 Bowel-wall thickening with multiple abscesses, abundant granulation, dense fibrous tissue, as seen in case 4 (fig 8a-d), chronic fistulas and draining sinuses to the surface are the characteristic features.3,9,10 These features are not specific to actinomy- cosis and may mimic neoplasm, or other infective processes such as tuberculosis, or chronic appendicitis.2,10,12 The sinuses draining to the surface with yellow sulphur granules are also not unique to actinomy- cosis, and may occur in nocardiasis, chro- momycosis and other fungal infections of the body.2 The aggressive infiltrative pat- tern of abdominopelvic actinomycosis has been described as an important radiologi- cal feature of this infection.3,5,13 Table II lists some of the imaging features of abdominopelvic actinomycosis. Conclusion In the absence of classical features of cutaneous sinuses with yellow sulphur granular discharge, the common imaging findings in abdominopelvic and thoracic actinomycosis may be nonspecific. Actinomycosis responds well to various antibiotic treatments, with or without sur- gical intervention. For this reason it is worthwhile including actinomycosis infec- tion in the differential diagnosis, particu- larly where clinical findings do not support the diagnosis of other processes such as tuberculosis or neoplasm. Actinomycosis should also be considered in situations where there is prolonged IUCD use, previ- ous pelvic or abdominal surgery or in appendicular infection. References 1. Ossorio MA, Fields CL, Byrd RP, Roy TM. Thoracic actinomycosis and human immunodefi- ciency virus infection. South Med J 1997; 90: 1136- 1138. 2. Smego RA jun., Foglia G. Actinomycosis. Clin Infect Dis 1998; 26: 1255-1263. 3. Lee I, Ha HK, Park CM, et al. Abdominopelvic actinomycosis involving the gastrointestinal tract: CT features. Radiology 2001; 220: 76-80. 4. Sumoza D, Raad I, Douglas E. Differentiating tho- racic actinomycosis from lung cancer. Infect ions in Medicine 2000; 17: 695-698. 5. Ko SF, Ng SH, Lee TY, Lo CW. Retroperitoneal actinomycosis with intraperitoneal spread: stellate pattern on CT. Clin Imaging 1996; 20: 133-136. 6. Cheon JE, Lm JG, Kim MY, Lee JS, Choi GM, Yeon KM. Thoracic actinomycosis: CT findings (abstract). Radiology 1998; 209: 229-233. 7. Menard HA Hypertrophic osteoarthropathy. eMedicine-hypertrophic osteoarthropathy . http://www.emedicine.com/med/topic2929.htm April 2003. 8. Burton MD, Mark EJ. Case 46-1994- A 35 year-old smoker with an air fluid level in the upper lobe bulla. N Engl J Med 1994; 31: 1761-1767. 9. Goldwag S, Abbitt PL, Watts B. Case report: per- cutaneous drainage of periappendiceal actinomy- cosis (abstract). Clin Radiol 1991; 44: 422-424. 10. Kaliaras V, Mylaria S, Lyra S, Tasonidou D, Thanos L. Ileo-caecal actinomycosis 2002 Dec 27 {online} URL: http://www.eurorad.org/ case. cfm?uid=2091luxembourg,euromultimedia 11. Yeguez JF, Mortinez SA, Sanda LP, Hellinger MD. Pelvic actinomycosis presenting as malignant large bowel obstruction: a case report and a review of the literature (abstract). Am Surg 2000; 66(1): 85- 90. 12. Chaudhuri S, Billings PJ. Intra-abdominal actino- mycosis presenting as complex abdominopelvic mass. J Indian Med Assoc 2002; 100: 463-464. 13. Ha HK, Lee HJ, Kim H, et al. Abdominal actino- mycosis: CT findings in 10 patients (abstract). Am J Roentgenol 1993; 161: 791-794. 7 SA JOURNAL OF RADIOLOGY • December 2005 Table II. Radiological features of abdominopelvic actinomycosis 1. GIT mucosal fold thickening and ulceration (may resemble Crohn’s disease).3 2. Abdominal/pelvic infiltrative mass (often with multiple compartments involved). 3. Post-contrast CT may demonstrate homogeneous or inhomogeneous enhancement.3,5 4. Rupture of hollow viscus with free intra-abdominal air. 5. Chronic fistula and draining sinus- es. 6. Retroperitoneal, psoas muscle or liver abscess formation. 7. Minimal or absent ascites.3 8. Stellate infiltrates from mass lesion with mesenteric involvement.5 REVIEW ARTICLE 7 11/25/05 1:49 PM Page 7