Figure 1
Swelling and 2 small air bubbles in the left subscapular muscle
Swelling of the muscles at the left upper arm is visible. 2 very small air bubbles can be seen in the subscapular muscle.
Tissue air bubbles in necrotising fasciitis without gas producing bacteria
SectionMusculoskeletal system
Case TypeClinical Cases
Authors1Marklund M, 2Skjoennemand M.
Connected authors
63 years, male
Clinical History
The patient presented with a swollen and slightly red left upper arm, initially treated as erysipelas. Two hours later the swelling involved the lateral breast wall, the pectoral and the deltoid muscle. Ultrasound excluded thrombosis. The patient became confuse with decreasing blood pressure. Blisters appeared and a CT was performed.
Imaging Findings
At the initial ultrasound examination diffuse subcutaneous oedema and areas of hypoechoic, oedematous muscle tissue was seen (Fig. 1).
An unenhanced CT (due to low GFR) showed axillary oedema with enlarged lymph nodes, severe subcutaneous swelling and thickened muscles on the left upper arm. The lateral breast was involved as well as the rotator cuff, the triceps-, biceps-, deltoid-, trapezoid- and the pectoral muscles. Also a slight thickening of the left sternocleid muscle was noted.
3 small (1-2 mm) air bubbles were detected close to the left humeroscapular joint and in the subscapular muscle (Fig. 2-4). One air bubble (1 mm) was present in the left sternocleid muscle. No iv-injection or blood testing had been performed at the left arm. Based on the rapid progression of symptoms and the detection of even a minimal air development, the patient was suspected having necrotising fasciitis and underwent acute surgery.
An unenhanced CT (due to low GFR) showed axillary oedema with enlarged lymph nodes, severe subcutaneous swelling and thickened muscles on the left upper arm. The lateral breast was involved as well as the rotator cuff, the triceps-, biceps-, deltoid-, trapezoid- and the pectoral muscles. Also a slight thickening of the left sternocleid muscle was noted.
3 small (1-2 mm) air bubbles were detected close to the left humeroscapular joint and in the subscapular muscle (Fig. 2-4). One air bubble (1 mm) was present in the left sternocleid muscle. No iv-injection or blood testing had been performed at the left arm. Based on the rapid progression of symptoms and the detection of even a minimal air development, the patient was suspected having necrotising fasciitis and underwent acute surgery.
Discussion
Necrotising fasciitis (NF) is a rare (4 in 100.000 persons/year) but serious, progressive and rapidly spreading infection localised in the profound fascia with secondary necrosis of muscles and subcutaneous tissue. NF is caused by infection with Grp. A Haemolytic Streptococcus, sometimes in combination with other aerobe or anaerobe bacteria species such as Bacteroides spp., Clostridium Perfringens, Peptostreptococcus spp., Enterobacteriaceae, Proteus spp., Klebsiella spp. and Pseudomonas Aeruginosa. Also fungal infections can lead to NF. The bacteria spreads haematogenic (e.g. from a joint infection), from the surface following trauma or from viscera after surgery [1]. Still a large number of cases are idiopathic. Insulin dependent diabetes, alcoholism, drug abuse, overweight and suppression of the immune system, seem to be predisposing factors. NF carries a high mortality rate (25-50%) and therefore determining the diagnosis with no delay followed by correct treatment is essential and lifesaving [2].
The patient typically presents with a swollen, painful, red extremity [3]. Often antibiotic treatment has been given prior to attendance but with no effect. The swelling may progress rapidly (within hours) and haemorrhagic blisters on the swollen skin may appear. The patients temperature is often elevated and signs of infection may be seen in the blood tests. If the right treatment is not given initially, the clinical situation may progress into pre-shock, confusion and, eventually, death [4, 5].
In the present case, the patient had no predisposing morbidity. Venous thrombosis was excluded. Due to the rapid progression of the clinical symptoms combined with the few tissue air bubbles detected at the CT-examination, acute surgery with complete opening of the rotator cuff and debridement was performed. The patient received hyper bar oxygen treatment, recovered after a few weeks and underwent reconstructive surgery with a good result. The infection had spread from the left shoulder joint and only Grp. A Haemolytic Streptococcus was found.
This case is interesting, since only a few air bubbles were present in the tissue. The majority of cases published demonstrate a large amount of free air, which really makes the diagnosis very easy. The radiologist needs to remember, that even though a gas producing bacteria, such as Clostridium Perfringens, is not present, air may still be detected in the tissue due to the CO2 production following fermentation and the rapid necrosis. Therefore the presence of even a single air bubble strongly supports the diagnosis of NF and surgical action must be instantly initiated.
The patient typically presents with a swollen, painful, red extremity [3]. Often antibiotic treatment has been given prior to attendance but with no effect. The swelling may progress rapidly (within hours) and haemorrhagic blisters on the swollen skin may appear. The patients temperature is often elevated and signs of infection may be seen in the blood tests. If the right treatment is not given initially, the clinical situation may progress into pre-shock, confusion and, eventually, death [4, 5].
In the present case, the patient had no predisposing morbidity. Venous thrombosis was excluded. Due to the rapid progression of the clinical symptoms combined with the few tissue air bubbles detected at the CT-examination, acute surgery with complete opening of the rotator cuff and debridement was performed. The patient received hyper bar oxygen treatment, recovered after a few weeks and underwent reconstructive surgery with a good result. The infection had spread from the left shoulder joint and only Grp. A Haemolytic Streptococcus was found.
This case is interesting, since only a few air bubbles were present in the tissue. The majority of cases published demonstrate a large amount of free air, which really makes the diagnosis very easy. The radiologist needs to remember, that even though a gas producing bacteria, such as Clostridium Perfringens, is not present, air may still be detected in the tissue due to the CO2 production following fermentation and the rapid necrosis. Therefore the presence of even a single air bubble strongly supports the diagnosis of NF and surgical action must be instantly initiated.
Differential Diagnosis List
Necrotising faciitis
Erysipelas (Streptococcus Pyogenes)
Venous thrombosis
Final Diagnosis
Necrotising faciitis
References
[1] GG Kihiczak, RA Schwartz, R Kapila (2006) Necrotizing fasciitis: a deadly infection. Journal of European Academy of Dermatology and Venereology Apr;20(4):365-9. (PMID: 16643131)
[2] R Puvanendran, JCM Huey and S Pasupathy (2009) Necrotizing Fasciitis. Canadian Family Physician Oct;55(10):981-87 (PMID: 19826154)
[3] AJ Headly (2003) Necrotizing soft tissue infections: a primary care review. American Family Physician Jul 15;68(2):323-8 (PMID: 12892352)
[4] I Brook (2008) Microbiology and management of soft tissue and muscle infections. Int J Surg Aug;6(4):328-38 (PMID: 17720643)
[5] NF Crum-Cianflone (2006) Infection and musculoskeletal conditions: Infectious myositis. Best Pract Res Clin Rheumatol Dec;20(6):1083-97 (PMID: 17127198)
Case information
| URL: | https://www.eurorad.org/case/10856 |
| DOI: | 10.1594/EURORAD/CASE.10856 |
| ISSN: | 1563-4086 |
Figure 2
One small air bubble in the left shoulder joint
In the left shoulder joint a very small air bubble can be seen.
Figure 3
One small air bubble in the left sternocleid muscle
In the left sternocleid muscle a very small air bubble can be seen.
Figure 4
Oedematous muscle at the left upper arm
The muscles at the left upper arm are seen with hypo echoic areas suggestive of oedema.
Swelling and 2 small air bubbles in the left subscapular muscle
Swelling of the muscles at the left upper arm is visible. 2 very small air bubbles can be seen in the subscapular muscle.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
One small air bubble in the left shoulder joint
In the left shoulder joint a very small air bubble can be seen.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
One small air bubble in the left sternocleid muscle
In the left sternocleid muscle a very small air bubble can be seen.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
Oedematous muscle at the left upper arm
The muscles at the left upper arm are seen with hypo echoic areas suggestive of oedema.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.
Marklund M, Dept. Radiology, University Hospital Roskilde, Denmark.