look before you cut · 2019. 1. 19. · 1/14/2019 1 look before you cut: skin and soft tissue...
TRANSCRIPT
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Look before you cut:Skin and Soft Tissue
UltrasoundAbi Brackney MD FACEP
Objectives
• Describe the scanning technique for skin and soft tissue infections
• Understand the ‘normal’ appearance of abscesses on ultrasound
• Identify structures on ultrasound that may mimic an abscess
• Describe techniques to help differentiate an abscess from other mimics
• Want to start scanning your skin and soft tissue infections
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Scanning
• Linear, high frequency probe
• May need a lower frequency probe for deeper
structures
• Cover the probe
• Hold the probe correctly
• Use a lot of gel
• Water baths or stand-off pads may be helpful
Scanning
• Always scan in two planes starting away from the
area of interest on normal tissue
• Scan slowly all of the way through until normal
tissue again
• Use the ‘normal’ contralateral side for
comparison
• Use color flow to help distinguish from vessels
• Adjust the gain, frequency, and focal zone as
needed
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Normal Anatomy
• Dermis and Epidermis
• Hypodermis/Subcutaneous layer – fat
• Fascia
• Muscle
• Other structures: vessels,
tendons/ligaments, nerves
Normal Tissue
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Cellulitis
Cellulitis
O vs CHF or DVT or lymphedema or renal
failure or venous stasis
O Color Doppler may show hyperemia in
cellulitis
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Abscess
O Normal appearance…
O Somewhat spherical
O Irregular or lobulated borders that may be
well demarcated or blend in with the
surrounding tissue
O Anechoic to hyperechoic
O May have septations, sediment/debris
within the cavity
Abscesses
O Use color flow to help differentiate from
vascular structures
O Swirling (PUSstalsis)
O Posterior enhancement
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When and Why to scan
• Uncertain clinical exam
• Changes management in up to 50% of cases
• Pediatrics – may avoid an unnecessary sedation
• Good to practice on ones you’re certain of to get an idea of what abscess can look like
• High risk areas – inguinal region, abdomen, neck
• To guide needle aspiration
• Better than CT too
• Decreased LOS compared to radiology scanning
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To cut or not to cut…that is the question
Case 1
O 41 yo female presents with chief complaint
of abscess. She has had left groin swelling
for the last week. She saw her pcp who ‘did
nothing’ but referred her to a surgeon.
Presents today because she can’t wear her
lulu leggings because of the obvious
swelling.
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O Are you cutting?
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Lymph Nodes
Lymph Nodes
O Oval
O Highly vascular
O No swirling with compression
O Hyperechoic center with hypoechoic ring
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Case 2
O 26 yo male comes in with chief complaint of
wound infection. He had a laceration to his
hand repaired 4 weeks prior at an outside
emergency department. He removed the
stitches himself. Now complains of swelling
and drainage at the site.
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O Are you cutting?
Pseudoaneruysm
O Color flow - ying-yang
O Thin neck
O Can be from an arterial puncture but also
from trauma
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Case 3
O 32 yo male presents with chief complaint of
arm infection. He has a history of IVDU but
has been on suboxone for the last three
months.
O Physical exam shows a large swelling in his
anticubital fossa that is erythematous and
tender.
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O Are you cutting?
O Always look in two planes…
O To cut?
O Upon further questioning the patient had
crushed up his suboxone and injected it.
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Other structure to look for
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Case 4
O 46 yo male presents for hand infection. Was
seen the day before in your emergency
department and placed on oral antibiotics
for cellulitis. No ultrasound performed the
day before.
O Physical exam shows an area of induration
over the first metacarpal without definite
fluctuance.
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O Cut or continue antibiotics?
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Case 5
O 37 yo obese male with no significant pmh comes in with complaint of gluteal infection.
O Hey you want to tell me how big this abccess is?
O Physical exam shows an erythematous, indurated area from the left buttock to posterior thigh to scrotum but not affecting the scrotum.
O Patient falling asleep during exam.
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O To cut?
O Diagnosis?
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Necrotizing Fasciitis
O Air in soft tissue
O Marked thickening of the subcutaneous
tissue
O Distorted and thickened fascial layer
O Perifascial fluid over 4mm
O Involves deeper layers than cellulitis
Necrotizing Fasciitis
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Case 6
O 73 yo female with a history of severe
dementia, sent in from her nursing home for
fever and breast abscess.
O Resident brings you the following image.
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O You cutting?
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Breast Abscesses
O Studies shows breast abscess less than 3-5
cm do well with ultrasound guided needle
aspiration and washout vs incision and
drainage.
Case 7
• 62 yo male presents with groin pain and
palpable mass 3 days after a cardiac cath.
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Vs hematoma
• Hard to distinguish vs abscess
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When and Why to scan
• Uncertain clinical exam
• Changes management in up to 50% of cases
• Pediatrics – may avoid an unnecessary sedation
• Good to practice on ones you’re certain of to get an idea of what abscess can look like
• High risk areas – inguinal region, abdomen, neck
• To guide needle aspiration
• Better than CT too
• Decreased LOS compared to radiology scanning
References
• Chandika et al. Ultrasound Guided Needle Aspiration versus Surgical Drainage in the
management of breast abscesses: a Ugandan experience. BMC Res Notes. 2012; 5: 12.
• Sonoguide.com
• Tayal VS, Hasan N, Norton HJ, Tomaszewski CA. The effect of soft-tissue ultrasound on
the management of cellulitis in the emergency department. Acad Emerg Med. 2006
Apr;13(4): 384-8.
• Adhikari and Blaivas, Sonography first for subcutaneous abscess and cellulitis
evaluation. J Ultrasound Med 2012; 31:1509-12.
• Chen et al. An overview of point-of-care ultrasound for soft tissue and musculoskeletal
application in the emergency department. J Intensive Care. 2016; 4: 55.
• Subramaniam et al. Point-of-care ultrsound for diagnosis of abscess in skin and soft
tissue infections. Acad Emerg Med. 2016 Nov;23(11): 1296-1306.
• O’Rourke et al. Ultrasound for the Evaluation of Skin and Soft Tissue Infections. Mo Med.
2015 May-Jun;112(3): 202-205.
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