Gout, Arthritis and Joint Pain

The most common joint affected by gout is the 1^st metatarsophalangeal joint. The most common joint affected by pesudogout is the knee joint (Figure 1). Gout and pseudogout are similar problems with different causes.

Gout is caused by the buildup of uric acid and the deposit of uric acid crystals inside a joint. The best test to diagnose gout is with a joint fluid analysis. Elevated uric acid is not a good criteria. 90% of patients suffering from gout are men between the ages of 40-60 years. Gout crystals are needle shaped and negatively birefringent. When placed under polarized light they will be yellow (Figure 2).

Uric acid builds up the body by two main mechanisms. These two mechanisms are excessive urate production and diminished urate clearance. Uric acid is produced from the breakdown of proteins inside the body and from the proteins of food that is eaten.

Precipitating Factors:

The sudden attack of gout can be brought on by anything that increases the level of uric acid in the blood such as dehydration, increased consumption of alcohol, eating large amount of meat or seafood, and trauma/surgery.

Diagnostic Testing:

Aspiration and analysis of the joint fluid is the best method for diagnosis (Figure 3). There are blood tests such as white blood cell count, C-reactive protein, erythrocyte sedimentation rate, and uric acid level that are helpful in supporting the diagnosis if elevated, but if normal, it cannot definitively rule out gout or pseudogout.

Pesudogout or chondrocalcinosis is the deposition of calcium pyrophosphate dehydrate crystals in the hyaline cartilage or fibrocartilage (CPPD). Pseudogout is a metabolic disease where calcium pyrophosphate dehydrate crystals (CPPD) are formed within the joint space. It most often affects the knee and occurs more in older patients. It is a calcification of fibrocartilage (chondrocalcinosis). Pseudogout crystals are rhomboid shaped and positively birefringent. Crystals will be blue when placed under polarized light (Figure 4). Associated conditions are hyperparathyroidism, rheumatoid arthritis and gout.

Gout and pseudogout both show a sudden onset of pain, redness and swelling typically affecting a single joint in 80% of the cases. Gout symptoms include joint pain, swelling and arthritis. Patients with gout have periarticular erosions along with the formation of uric acid soft tissue masses in and around the joint which can be seen on x-ray. Soft tissue tophus deposition with periarticular erosions called “punch-out” lesions (Figure 5).

X-rays in pseudogout will show this calcification in the articular cartilage or menisci, with involvement of the patellofemoral joint (Figure 6). Calcifications of the synovium, tendon, and ligaments can also be seen.

Treatment of Gout and Pseudogout:

Acute gout can be treated with indocine and colchicine (be aware of peptic ulcer). In cases of chronic gout the patient will be treated with allopurinol (xanthine oxidase inhibitor) and colchicine. Uricosuric drugs such as Probenecid may increase uric acid excretion by the kidneys may be helpful. Pseudogout is treated with NSAIDs and intra-articular injections.

Precious Blood Supply of Bones

There are five major bones with previous blood supply. Fractures in these bones can interrupt this peculiar blood supply, causing a threat of death of the bone and nonunion of the fracture. Fractures in these areas usually occur as a result of trauma or stress related injuries.

These areas are the proximal humerus, scaphoid, proximal femur, talus, and fifth metatarsal. Interruption of the blood supply causes death of the bone and nonunion.

 

There are three types of fractures at the fifth metatarsal; avulsion fracture, Jones fracture, and mid-shaft fractures. The avulsion and mid-shaft fractures have good healing due to a sufficient blood supply. The Jones fracture compromises the blood supply which leads to nonunion of the fracture. Treatment can be achieved by non-weight bearing immobilization or may require intramedullary screw fixation in athletes and active individuals.