Differential Diagnosis for Swelling under Skin after Cannula Removal
- Single most likely diagnosis
- Hematoma: This is the most likely diagnosis as it is a common complication after cannula removal, especially if the site was not adequately compressed or if the patient has a bleeding tendency. Hematoma formation occurs when blood leaks into the tissues under the skin.
- Other Likely diagnoses
- Infection or abscess: Although less common than hematoma, infection can occur at the site of cannula insertion, especially if the cannula was in place for an extended period or if sterile technique was not followed. Swelling, redness, and warmth are signs of infection.
- Seroma: A seroma is a collection of fluid that can occur after the removal of a cannula, especially if there was significant tissue disruption during insertion or removal. It presents as a swelling under the skin that may be tender but is usually not as firm as a hematoma.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Necrotizing fasciitis: Although rare, this is a life-threatening infection that requires immediate attention. It can present with swelling, pain, and redness, but the skin may also appear pale or dusky, and there may be signs of systemic infection such as fever and tachycardia.
- Compartment syndrome: This is a condition where increased pressure within a muscle compartment leads to muscle and nerve damage. It can occur after cannula removal if there is significant bleeding or fluid accumulation. Symptoms include severe pain, swelling, and decreased sensation or movement in the affected limb.
- Rare diagnoses
- Pseudaneurysm: A rare complication that can occur if the cannula damages an artery, leading to the formation of a false aneurysm. It presents as a pulsatile swelling under the skin.
- Arteriovenous fistula: Another rare complication where an abnormal connection forms between an artery and a vein, usually due to trauma from the cannula. It can cause swelling, pain, and a palpable thrill or bruit over the affected area.