Pseudogout and Chondrocalcinosis

Discussion

• acute arthritis caused by CPPD crystal-induced inflammation;
• almost as common as gout & may perfectly mimic gout during acute flare;
• pseudogout attacks occurring before age 50 are uncommon;
• see: pseudogout occurence after joint replacement
• references:
  • A histological study of calcium pyrophosphate dihydrate crystal-deposition disease.
  • Clinical features of pseudogout attack. A survey of 50 cases.

differential diagnosis

• pseudogout occurence after joint replacement:
• septic arthritis:
  • pseudogout may be confused with septic arthritis;
  • chondrocalcinosis of the meniscus occurs not only in otherwise healthy individuals in older age groups but also in definite association w/ several distinct metabolic disorders;
  • references:
    • Monoarticular pseudogout of the hip presenting as septic arthritis: a case report.
    • Presence of crystals is not an evidence of absence of infection.
• trauma:
  • perhaps the majority of cases of chondrocalcinosis occur from trauma;
  • reference: Localized chondrocalcinosis in traumatized joints.
• hemochromatosis;
• hyperparathyroidism (most common);
  • up to 30% of hyperparathyroid pts have chondrocalcinosis;
• hypothyroidism;
• gout:
  • reference: Gout and coexisting pseudogout in the knee joint.
• hyperparathyroidism
• hypothyroidism
• hemochromatosis
• ochronosis
  • ochronosis is a hereditary enzyme deficiency (homogentisic acid oxidase) resulting in deposition of homogentisic acid polymers in articular cartilage
• acromegaly
• Paget's disease;
• hypomagnesemia
  • references:
    • Hypomagnesemia associated with chondrocalcinosis: a cross-sectional study
    • Images in clinical medicine. Chondrocalcinosis and hypomagnesemia.

Clinical Features

• most often affects the knee and the wrists;

CPPD Crystal Exam

• Crystal Examination of Synovial Fluid:
• Calcium pyrophosphate dihydrate crystals are visualized under compensated polarized light microscopy
  • crystals may be more difficult to detect than MSU crystals because of their smaller size, more intraphagolysosomal location, & less brilliant colors;
  • in contrast to MSU crystals, CPPD crystals show weak positive birefringency and have squared or rhomboidal shaped ends;
  • aggregates do not show birefringence (or are weakly birefringent) under polarized light;
  • alizarin red stain, can confirm that these clumps are masses of calcium crystals;

Radiographic Analysis

• punctate and linear densities in hyaline or fibrocartilage, which are found in knee menisci, acetabular labrum, & TFCC;

Therapeutic Principles

• aspiration of joint and steroid injection, once diagnosis of infection has been excluded, will usually control symptoms;
  • references:
    • Rapidly destructive tibiofemoral knee osteoarthritis: presentation and outcome after global medical treatment including non-arthroscopic joint lavage plus corticosteroid injection. A single center retrolective study.
• indomethacin;
• colchicine? may be useful for pseudogout;
• magnesium on an as needed basis
• arthroscopic lavage:
  • Joint lavage and pseudogout

References

• Treating difficult crystal pyrophosphate dihydrate deposition disease
• Arthroscopy and chondrocalcinosis.