Crystal arthropathy

Crystal arthropathy
Classification and external resources
Specialty	rheumatology
ICD-10	M10-M11
ICD-9-CM	712

Crystal arthropathy is a class of joint disorder (called arthropathy) that is characterized by accumulation of tiny crystals in one or more joints. Polarizing microscopy and application of other crystallographic techniques have improved identification of different microcrystals including monosodium urate, calcium-pyrophosphate dihydrate, calcium hydroxyapatite, and calcium oxalate.^[1]

Types include:

Name	Substance	Birefringence
Gout[2]	accumulation of uric acid	negative
Chondrocalcinosis[3] aka Pseudogout	accumulation of calcium pyrophosphate	positive

Risk factors

• Obesity
• Renal failure
• Hyperphosphatemia
• Hyperparathyroidism
• Hypercalcemia
• Tissue damage (dystrophic calcification)

Causes

• Deposition of crystals in joints
• Calcium-pyrophosphate dihydrate crystal formation:
  • Increased production of inorganic pyrophosphate
  • Decreased levels of pyrophosphatase in cartilage
  • Decreased levels of cartilage glycosaminoglycans
  • Hyperparathyroidism
  • Hemochromatosis^[4]
  • Hypophosphatasia^[5]
  • Hypomagnesemia
• Hydroxyapatite deposition:
  • Tissue damage
  • Hyperparathyroidism^[6]
  • Hypercalcemia
  • Hyperphosphatemia
• Calcium Oxalate deposition:
  • Enhanced production of oxalic acid due to enzyme defect
  • Poor excretion of oxalic acid in renal failure
  • Excessive ascorbic acid intake in renal failure

Differential diagnosis

• Infectious arthritis
• Type IIa hyperlipoproteinemia
• Amyloidosis
• Multicentric reticulohistiocytosis
• Hyperparathyroidism
• Spondyloarthropathy
• Rheumatoid arthritis
• Fibromyalgia

References

1. Mcgill NW (2000). "Gout and other crystal-associated arthropathies". Ballieri's Clinical Rheumatology 14 (3): 445–460. doi:10.1053/berh.2000.0087. PMID 10985980.
2. Choi H (May 2006). "Epidemiology of crystal arthropathy". Rheum. Dis. Clin. North Am. 32 (2): 255–73, v. doi:10.1016/j.rdc.2006.03.002. PMID 16716879.
3. Canhão H, Fonseca JE, Leandro MJ; et al. (2001). "Cross-sectional study of 50 patients with calcium pyrophosphate dihydrate crystal arthropathy". Clin. Rheumatol. 20 (2): 119–22. doi:10.1007/s100670170081. PMID 11346223.
4. Axford, DSc, MD, John S. "Rheumatic manifestations of hereditary hemochromatosis". UpToDate.com. Retrieved 10 September 2014.
5. "Hypophosphatasia Pathology". Hypophosphatasia.com. Retrieved 10 September 2014.
6. Geelhoed, GW; Kelly, TR (December 1989). "Pseudogout as a clue and complication in primary hyperparathyroidism". Surgery 6 (106): 1036–42. PMID 2588110.