Differential Diagnosis

• Single most likely diagnosis
  • Olecranon Bursitis: This condition is characterized by inflammation of the bursa at the elbow, which can be caused by trauma, such as a bump to the elbow. The patient's symptoms of a fluid-filled sac, warmth, itchiness, and pain are consistent with olecranon bursitis. The reduction in size of the sac after taking Tylenol may indicate a response to the anti-inflammatory effects of the medication.
• Other Likely diagnoses
  • Elbow Abscess: An abscess is a collection of pus that can form in response to a bacterial infection. The patient's symptoms of warmth, pain, and a fluid-filled sac could be consistent with an abscess. However, the rapid reduction in size of the sac after taking Tylenol makes this diagnosis less likely.
  • Elbow Hematoma: A hematoma is a collection of blood that can form in response to trauma. The patient's history of bumping his elbow and the formation of a bump that later went away could be consistent with a hematoma. However, the fluid-filled sac and warmth to touch make this diagnosis less likely.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Septic Arthritis: This is a bacterial infection of the joint that can cause severe pain, swelling, and warmth. While the patient's symptoms could be consistent with septic arthritis, the lack of systemic symptoms such as fever and the rapid reduction in size of the sac after taking Tylenol make this diagnosis less likely. However, septic arthritis is a medical emergency that requires prompt treatment, so it should not be missed.
  • Osteomyelitis: This is a bacterial infection of the bone that can cause pain, swelling, and warmth. While the patient's symptoms could be consistent with osteomyelitis, the lack of systemic symptoms such as fever and the rapid reduction in size of the sac after taking Tylenol make this diagnosis less likely. However, osteomyelitis is a serious condition that requires prompt treatment, so it should not be missed.
• Rare diagnoses
  • Gout or Pseudogout: These are types of arthritis that can cause sudden onset of pain, swelling, and warmth in a joint. While the patient's symptoms could be consistent with gout or pseudogout, the lack of a history of similar episodes and the presence of a fluid-filled sac make these diagnoses less likely.
  • Rheumatoid Arthritis: This is an autoimmune disease that can cause pain, swelling, and warmth in multiple joints. While the patient's symptoms could be consistent with rheumatoid arthritis, the lack of a history of similar episodes and the presence of a fluid-filled sac make this diagnosis less likely.