26th February 2025

A 45-year-old female is reviewed in rheumatology clinic.

A 45-year-old female is reviewed in rheumatology clinic. She has a diagnosis of juvenile idiopathic arthritis made at age 12. You note multiple deformed joints on examination. She also has pitting oedema of her lower limbs bilaterally to the level of the knee.

Her observations performed in clinic show a blood pressure of 167/98, heart rate of 77, oxygen saturation of 99% on room air and a temperature of 36.7 degrees.

Urinalysis shows protein 3+.

Urine protein creatinine ratio is sent from clinic and comes back at 563 mg/mmol (0-30 mg/mmol).

She is referred to the renal physicians who perform a renal biopsy in light of the significantly elevated protein:creatinine ratio. The histology report shows deposits in the glomeruli, which are red when seen on light microscopy and display green birefringence under polarised light.

What is the most likely diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.