25th February 2025

An 85-year-old lady presents with knee pain that has worsened over the past few days, and she is now unable to walk on it.

An 85-year-old lady presents with knee pain that has worsened over the past few days, and she is now unable to walk on it. There was no preceding trauma. She is on methotrexate for rheumatoid arthritis and beta blockers. Alongside rheumatoid arthritis, she has a past history of gout.

On examination, you noted a knee replacement scar and a warm, swollen and painful joint. She is not tachycardic, has a mild fever and bloods show a mildly raised white cell count.

Obs show: HR 78 BP 104/65 RR 21 Sats 96% on room air Temp 37.9

FBC shows:

Hb 112 (120-180)

MCV 105 (90-97)

Plts 200 (150-450)

WCC 13 (4-11)

Neutrophils 8.5 (1.5-8)

Lymphocytes 3.6 (1.1-4)

Monocytes 0.5 (0.2-1.1)

Eosinophils 0.2 (0.1-0.4)

Basophils 0.2 (0-0.3)

Arthrocentesis is performed, with results awaited. What is the best first treatment?