The patient is a 24-year-old female who presents to the emergency department for left middle finger pain and swelling. She is right hand dominant and works in a kitchen. The patient states that ten days ago she avulsed the distal tip of the left middle finger, including the majority of the nail. At that time, the patient was evaluated at an outside hospital where the wound was cauterized with silver nitrate due to soft tissue bleeding. Since then, the patient states that she has had swelling over the dorsal distal phalanx.
General: Alert, awake, oriented, and non-toxic without acute distress
Extremities:
- The left third digit is minimally swollen without significant erythema or drainage from the wound.
- There is brisk capillary refill over the volar aspect of the digit.
- The patient is able to fully flex the digit.
The remainder of the exam is unremarkable.
White Blood Cells: 6.7 cells/mm3
Erythrocyte Sedimentation Rate: 2 mm/hr
C-reactive Protein: 1.2 mg/L
Labs were otherwise normal.
- Distal phalanx fracture
- Retained foreign body
- Silver nitrate
- Osteomyelitis
Silver nitrate
The X-ray image shows a radiopaque density over the third distal phalanx. This is due to the silver nitrate that was used to cauterize the patient’s wound when she initially presented. The staining of the patient’s skin from the silver nitrate can be seen in the photo, which correlates with the areas of radiopacity on the X-ray.
Take-Home Points
- Silver nitrate is a common topical chemical cautery agent used to achieve hemostasis in soft tissue injuries. On the X-ray and computed tomography (CT) imaging, silver nitrate can appear as a radiopaque foreign body due to silver deposits in the tissue.
- It is important to know this characteristic of silver nitrate to avoid a misdiagnosis of retained foreign body and to prevent unnecessary surgical exploration. If silver nitrate is used for hemostasis before imaging is obtained it should be well documented and communicated to radiology.
- Tong, S. H. Y., W. L. Chan, and Y. L. Lee. “Silver nitrate stain masquerading as an avulsion fracture of the finger.” Hong Kong Journal of Emergency Medicine (2011): 47-49. DOI
- Healy, Claragh, et al. “Silver nitrate masquerading as a radiopaque foreign body.” Emergency radiology (2007): 63-64. PMID: 17342469
- Madan, Sunil I., and Katherine L. Heilpern. “Silver nitrate as a radiopaque foreign body.” Journal of Emergency Medicine (1999): 1045. PMID: 10595894
- Livingstone, Devon, et al. “Silver nitrate mimicking a foreign body in the pharyngeal mucosal space.” World journal of radiology (2015): 100. PMID: 26029352
- Narayan, N., et al. “The misleading appearance of silver nitrate on plain radiography.” The Annals of The Royal College of Surgeons of England (2014): e3-e4. PMID: 24780777
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