A 70 year old lady presents to your ED with a painful left knee. She has had three days of pain and swelling with intermittent fevers. On examination the knee is hot, red and swollen with a limited range of motion. She is apyrexial. She has severe difficulty weight bearing.
She has a history of recurrent UTI’s and is on prophylactic antibiotics.
You perform an aspirate of her knee which shows:
– volume 60 ml
– Description: turbid yellow
– Leucocytes 25000/uL
– Polymorphs 80%
– Mononuclear 20%
– RBC 1000/uL
1. Describe the abnormalities
2. Give 5 reasonable differential diagnosis
3. What 5 aspect of history are important?
4. What other investigations would you request?
5. What would you do next?