Portable ultrasound diagnoses flexor tendon sheath infection

Abstract

A 43-year-old car mechanic attended the emergency depart-mentaftersustainingapuncturewoundtohisrighthandonaglass fragment. The injury had occurred approximately 12 hearlier. The patient complained of marked pain within thepalm and was unable to use the hand. He had no constitu-tional upset and was apyrexial.Examination of the hand showed a small puncture woundovertheheadofthefourthmetacarpalonthepalmaraspect.There was no obvious cellulitis or tracking lymphangitis andno pus could be expressed from the wound. There wasmarked pain to firm palpation over the puncture wound withpain also being elicited on passive movement of the finger.Examination of the rest of the hand was normal.The clinical impression was that of a glass foreign bodywithin the palm and the X-rays of the hand were requested.Therewassomesuspicionofaglassshardoncloseinspectionoftheradiographs(seeFig.1).Anincidentalfindingofametallicforeignbodywasalso seenoverthe5thmetacarpophalangealjointrepresentinga previousinjury.Anultrasound scanoftheareawasperformedinthedepartmenttoconfirmthepresenceof a glass shard, the area was scanned using a Sonosite Micro-maxx with a 10—5 MHz linear transducer.The scans did indeed confirm a foreign body but moreimportantly revealed fluid within the flexor tendon sheath ofthe ring finger (see Fig. 2) suggesting penetration of thesheath and subsequent infection. Further scans of the rest ofthe hand did not show any involvement of the other digits(see Fig. 3).On the strength of the scan a diagnosis of tendon sheathinfection was made. The patient was then commenced onintravenous co-amoxiclav and metronidazole and taken totheatre where the glass shard was removed and the tendon