Notably, there are a number of other crystal deposit diseases that are more rare, which I will briefly mention here:
Basic calcium phosphate or BCP (formerly “calcium apatite”)
First, basic calcium phosphate or BCP (formerly “calcium apatite”) :This form of crystal deposit disease occurs especially in a number of rheumatic conditions including scleroderma and dermatomyositis. Specifically, under the microscope it looks like snowball like clumps. (Ref. 1).
Second, a severe form of degenerative shoulder arthritis with BCP deposits has the name Milwaukee shoulder. In this condition of elderly women the fibrous rotator cuff certainly has damage from degeneration and BCP deposits to the point that the head of the humerus (upper arm bone) dislocates upwards into the shoulder roof.
Indeed, the radiologist can diagnose these cases because of a characteristic appearance on X-rays where cloud like opacities show up surrounding a joint. To emphasize, BCP is very irritating. The body releases prostaglandins which in turn trigger white blood cell release with damaging proteases that destroy joints and cartilage. Truly, colchicine and NSAIDs help the patient to a certain extent.
Third, cholesterol crystals: Indeed, inflammatory changes in bursae and degenerative joints can release cholesterol from inflammatory cells. In this case, subsequently cholesterol crystals deposit in these inflamed structures and irritate the tissues even more. Above all, treatment is directed at controlling the original inflammatory condition.
Calcium oxalate crystals
Finally, calcium oxalate crystals: Above all, patients with kidney damage who are on hemodialysis or peritoneal dialysis often get acute painful attacks similar to gout. Notably, X-rays look similar to pseudogout and BCP crystal deposit disease. To explain, these crystals, which under the polarized light microscope have a characteristic appearance of two glued together pyramids, often contained in the white blood cells of inflamed areas, can be found in joints, skin and even in blood vessel walls.
In essence, depending on what crystals are found, the treatment is modified by the treating physician to suit the clinical presentation.
1. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 55.
2. ABC of rheumatology, second edition, edited by Michael L. Snaith , M.D., BMJ Books, 1999.
3. Goldman: Cecil Textbook of Medicine, 21st ed.(©2000)W.B.Saunders
4. Ferri: Ferri’s Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc.
5. Rakel: Conn’s Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier