Question

A 51 year old man presents with swelling in both knees. The following morning, an arthrocentesis is performed and blood is collected for chemistry testing. Results are as follows:

•Synovial Fluid results:   

      Color – Yellow      

      Clarity – Cloudy

      WBC count – 43,000

                Pmns – 63%                                                     

                Monos – 24%

                Lymphs – 13%

      Crystals – many intracellular, needle-shaped crystals, negative birefringence

•Blood chemistry results:

Fasting glucose – 85 mg/dl  

Uric acid – 12.7 mg/dl

•gram stain: no organisms seen, many WBCs seen

Questions (please answer all!)

1. identify any abnormal results.

2. Of the 4 classifications of joint disorders, what would this fluid be classified as? What results led you to this classification? BE SPECIFIC!

3. What is the most likely identity of the crystals?

4. What is the most probable diagnosis?

5. If no crystals were observed, would the diagnosis change? Why or why not?   

Answer 1

1. The presence of crystals in synovial fluid indicate the prognosis of gout. Gout is characterized by altered Purine metabolism. Uric acid is formed in excess which gets deposited in joints and cause inflammation.

2. The fluid is categorized as : inflamamtory

3. The crystals are made of uric acid.Uric acid deposition causes inflammation.

4. The diagnosis includes joint fluid test (present of crystals in synovial fluid), blood test (diagnosis of uric acid in blood) and X ray analysis of joints.

5. The diagnosis would be reactive arthritis. It is due to bacterial infections.