Bedside US in the Diagnosis of Complex Hand Infections
A 30-year-old woman was transferred to the ED from an urgent care facility for a complicated hand infection thought to require surgical incision and drainage. The patient had been bitten on the dorsum of her hand several days earlier by her fully vaccinated cat and had noted worsening redness, swelling, and pain. Her ED evaluation revealed normal vital signs and two small puncture wounds on the lateral aspect of the dorsum of her hand. The EP noted redness and induration covering the first dorsal interosseous space of the hand and spreading proximally to the elbow. No areas of fluctuance were palpable, and she complained of exquisite tenderness with passive range of motion to the fingers and wrist.
As part of her evaluation, the EP performed a bedside ultrasound of the hand and forearm. This showed extensive soft-tissue cobblestoning along the dorsum of the hand, wrist, and distal forearm, but no areas of fluid collection. All tendons were well visualized and were free of surrounding fluid (Figure 1A, B). The patient was treated with 3 grams of intravenous ampicillin/sulbactam in the ED, and the edges of the induration were marked with a skin marker. She was discharged with a prescription for amoxicillin/clavulanate and instructed to return to the ED in 48 hours for a wound check, or earlier if the infection worsened. On her return visit, the redness and induration had markedly improved and the patient reported that her pain was much better. She was asked to finish the antibiotics and follow up with her primary care physician in a week.
(Enlarge Image)
Figure 1.
(A) Transverse view demonstrating "cobblestoning." Thickened and abnormally hyperechoic skin and subcutaneous tissue are interspersed by hypoechoic fluid in a reticular pattern. Tendons (white arrows) are not surrounded by fluid. (B) Longitudinal view of normal tendon without surrounding fluid.
A 33-year-old man with a history of intravenous drug abuse presented to the ED after a fall 10 days prior during which he sustained an abrasion to his right hand. Since the injury, the hand had continued to swell and became increasingly painful. At the time of presentation, his temperature was 38.2°C (100.8°F), and all other vital signs were within normal limits. Physical examination revealed extensive erythema, induration, warmth, and tenderness of the entire right hand and right forearm (Figure 2). Pain was exacerbated by any movement of the hand. An old abrasion over the dorsal right third metacarpophalangeal joint was noted, as well as multiple tract marks in the right antecubital fossa. Ultrasound was performed at the bedside, showing cobblestoning of the soft tissues along the dorsal surface of the right hand, and large hypoechoic collections were also noted in the space surrounding the extensor tendons (Figure 3A, B). Antibiotic therapy was initiated and Surgery consulted.
(Enlarge Image)
Figure 2.
Right dorsal hand and forearm are erythematous, swollen, and tender. The left arm has needle marks but does not otherwise appear infected.
(Enlarge Image)
Figure 3.
(A) Transverse view demonstrating soft tissue cobblestoning (white arrows) and fluid in the subaponeurotic space surrounding the extensor tendons (yellow arrows). (B) Longitudinal view.
The patient was taken to the operating room (OR) later that day and a large amount of purulent fluid was extruded from the dorsum of the patient's hand, originating from the dorsal subcutaneous and subaponeurotic spaces. He was eventually discharged with outpatient antibiotic therapy and recovered well.
A 32-year-old female cat groomer presented to the ED 12 hours after she was bitten in the hand by a cat. She complained of swelling and pain to the lateral hand, with limited range of motion to the thumb. On examination she was afebrile and had two small bite marks on the ventral surface of the hand over the metacarpophalangeal joint of the thumb. There was symmetric swelling of the thumb and fullness over the thenar eminence. Range of motion to the thumb was severely limited due to pain.
Bedside ultrasound demonstrated fluid circumferentially surrounding a single flexor tendon of the thumb but sparing other tendons (Figure 4A, B). Antibiotic therapy was initiated and Orthopedic Surgery consulted. The surgeon initially doubted tenosynovitis, but took the patient to the OR after reviewing the ultrasound findings. There she was found to have a swollen and cloudy flexor tendon sheath, which drained pus when excised. After drainage, irrigation, and closure, the patient did well postoperatively and was discharged with antibiotics. Cultures eventually grew Pasteurella multocida. At a follow-up clinic visit, she was healing well and had full active and passive range of motion without discomfort.
(Enlarge Image)
Figure 4.
(A) Transverse view showing fluid circumferentially surrounding a flexor tendon of the thumb (white arrow). Other tendons (yellow arrow) are unaffected. (B) Longitudinal view.
A 46-year-old woman presented to the ED for a cat bite on her right index finger that had occurred the previous day. She complained of significant swelling, pain, and redness to the entire finger that made any movement impossible. She was afebrile and had four small puncture wounds on the dorsal and volar side of the proximal interphalangeal (PIP) joint of the index finger. The finger was symmetrically swollen and erythematous, especially along the volar surface, and the patient was unable to perform any active or passive range of motion due to pain. The physician had clinical suspicion for flexor tenosynovitis, so placed a surgical consult and began treatment with intravenous antibiotics.
In agreement with the clinical examination, a water bath ultrasound examination (Figure 5) did show anechoic fluid along the flexor tendon, but also a fluid collection in the joint space of the PIP joint. Although initially doubtful of the diagnosis of septic arthritis, in the OR the orthopedic surgeon identified pus located in both the flexor tendon sheath and the joint capsule. Cultures identified P. multocida. She was uneventfully discharged after a short hospital stay, and at a follow-up visit 1 month later she was healing well and working to improve range of motion with physical therapy.
(Enlarge Image)
Figure 5.
Longitudinal view of the index finger under water bath ultrasound showing fluid around the flexor tendon (white arrow) as well as inside the joint capsule of the proximal interphalangeal joint (yellow arrow).
Case Reports
Case 1
A 30-year-old woman was transferred to the ED from an urgent care facility for a complicated hand infection thought to require surgical incision and drainage. The patient had been bitten on the dorsum of her hand several days earlier by her fully vaccinated cat and had noted worsening redness, swelling, and pain. Her ED evaluation revealed normal vital signs and two small puncture wounds on the lateral aspect of the dorsum of her hand. The EP noted redness and induration covering the first dorsal interosseous space of the hand and spreading proximally to the elbow. No areas of fluctuance were palpable, and she complained of exquisite tenderness with passive range of motion to the fingers and wrist.
As part of her evaluation, the EP performed a bedside ultrasound of the hand and forearm. This showed extensive soft-tissue cobblestoning along the dorsum of the hand, wrist, and distal forearm, but no areas of fluid collection. All tendons were well visualized and were free of surrounding fluid (Figure 1A, B). The patient was treated with 3 grams of intravenous ampicillin/sulbactam in the ED, and the edges of the induration were marked with a skin marker. She was discharged with a prescription for amoxicillin/clavulanate and instructed to return to the ED in 48 hours for a wound check, or earlier if the infection worsened. On her return visit, the redness and induration had markedly improved and the patient reported that her pain was much better. She was asked to finish the antibiotics and follow up with her primary care physician in a week.
(Enlarge Image)
Figure 1.
(A) Transverse view demonstrating "cobblestoning." Thickened and abnormally hyperechoic skin and subcutaneous tissue are interspersed by hypoechoic fluid in a reticular pattern. Tendons (white arrows) are not surrounded by fluid. (B) Longitudinal view of normal tendon without surrounding fluid.
Case 2
A 33-year-old man with a history of intravenous drug abuse presented to the ED after a fall 10 days prior during which he sustained an abrasion to his right hand. Since the injury, the hand had continued to swell and became increasingly painful. At the time of presentation, his temperature was 38.2°C (100.8°F), and all other vital signs were within normal limits. Physical examination revealed extensive erythema, induration, warmth, and tenderness of the entire right hand and right forearm (Figure 2). Pain was exacerbated by any movement of the hand. An old abrasion over the dorsal right third metacarpophalangeal joint was noted, as well as multiple tract marks in the right antecubital fossa. Ultrasound was performed at the bedside, showing cobblestoning of the soft tissues along the dorsal surface of the right hand, and large hypoechoic collections were also noted in the space surrounding the extensor tendons (Figure 3A, B). Antibiotic therapy was initiated and Surgery consulted.
(Enlarge Image)
Figure 2.
Right dorsal hand and forearm are erythematous, swollen, and tender. The left arm has needle marks but does not otherwise appear infected.
(Enlarge Image)
Figure 3.
(A) Transverse view demonstrating soft tissue cobblestoning (white arrows) and fluid in the subaponeurotic space surrounding the extensor tendons (yellow arrows). (B) Longitudinal view.
The patient was taken to the operating room (OR) later that day and a large amount of purulent fluid was extruded from the dorsum of the patient's hand, originating from the dorsal subcutaneous and subaponeurotic spaces. He was eventually discharged with outpatient antibiotic therapy and recovered well.
Case 3
A 32-year-old female cat groomer presented to the ED 12 hours after she was bitten in the hand by a cat. She complained of swelling and pain to the lateral hand, with limited range of motion to the thumb. On examination she was afebrile and had two small bite marks on the ventral surface of the hand over the metacarpophalangeal joint of the thumb. There was symmetric swelling of the thumb and fullness over the thenar eminence. Range of motion to the thumb was severely limited due to pain.
Bedside ultrasound demonstrated fluid circumferentially surrounding a single flexor tendon of the thumb but sparing other tendons (Figure 4A, B). Antibiotic therapy was initiated and Orthopedic Surgery consulted. The surgeon initially doubted tenosynovitis, but took the patient to the OR after reviewing the ultrasound findings. There she was found to have a swollen and cloudy flexor tendon sheath, which drained pus when excised. After drainage, irrigation, and closure, the patient did well postoperatively and was discharged with antibiotics. Cultures eventually grew Pasteurella multocida. At a follow-up clinic visit, she was healing well and had full active and passive range of motion without discomfort.
(Enlarge Image)
Figure 4.
(A) Transverse view showing fluid circumferentially surrounding a flexor tendon of the thumb (white arrow). Other tendons (yellow arrow) are unaffected. (B) Longitudinal view.
Case 4
A 46-year-old woman presented to the ED for a cat bite on her right index finger that had occurred the previous day. She complained of significant swelling, pain, and redness to the entire finger that made any movement impossible. She was afebrile and had four small puncture wounds on the dorsal and volar side of the proximal interphalangeal (PIP) joint of the index finger. The finger was symmetrically swollen and erythematous, especially along the volar surface, and the patient was unable to perform any active or passive range of motion due to pain. The physician had clinical suspicion for flexor tenosynovitis, so placed a surgical consult and began treatment with intravenous antibiotics.
In agreement with the clinical examination, a water bath ultrasound examination (Figure 5) did show anechoic fluid along the flexor tendon, but also a fluid collection in the joint space of the PIP joint. Although initially doubtful of the diagnosis of septic arthritis, in the OR the orthopedic surgeon identified pus located in both the flexor tendon sheath and the joint capsule. Cultures identified P. multocida. She was uneventfully discharged after a short hospital stay, and at a follow-up visit 1 month later she was healing well and working to improve range of motion with physical therapy.
(Enlarge Image)
Figure 5.
Longitudinal view of the index finger under water bath ultrasound showing fluid around the flexor tendon (white arrow) as well as inside the joint capsule of the proximal interphalangeal joint (yellow arrow).
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