| What is calcium pyrophosphate deposition disease? | Metabolic arthropathy caused by deposition of CPD in and around joints especially articular and fibrocartilage, often asymptomatic, with only radio changes seen, various clinical manifestations may occur include acute (pseudogout) and chronic arthritis.
Almost any joint involved mostly knees, wrists and hips, it is most common cause of secondary metabolic osteoarthritis.
Five common presentations (asymptomatic [lanthanic] CPPD, acute pseudogout, pseudoosteoarthritis, pseudorheumatoid arthritis, pseudoneuropathic joints)
Prognosis (significant morbidity due to acute attack pain, tx is important to prevent further end-organ damage but cannot reverse the joint disease) |
| How is etiology of CPPD? | Unknown, increased ATP breakdown w/resultant increased inorganic PP in joints resulting from aging, genetic factors, or both.
Changes in cartilage matrix may play an important role promoting CPPD, rare heriditary form of CPPD occur auto dominant. |
| How is epidemiology of CPPD? | 50% people older than 85 years have chondrocalcinosis, sex and age related demographic (more in women than men slightly, if early associated with secondary cause like metabolic syndrome/familial cause)
Comorbidities (HyperPTH, gout, osteoarthritis, RA, hemochromatosis, osteoporosis, hypoMg, CKD, calcium supplementation |
| How is clinical presentation of CPPD? | Asymptomatic (Lanthanic, radio chondrocalcinosis most common form, hyaline cartilage and fibrocartilage of knees, triangular ligament of wrist , of pubis symphysis, acetabulum)
Acute Pseudogout (acute monoarticular/oligoarticular arthritis, 25% of cases, acute monoarthritis with pain and swelling, olyarticular may occur on occasion, could be precipitated by MI, CHF, stroke, surgery, trauma increasing calcium level)
Pseudo-osteoarthritis (MCP, wrists, elbows, shoulders unlikely, knees, spine occur in primary osteo-arthritis, 50% of all cases and half are pseudogout)
PseudoRA (5% of pt, symmetrical inflammation of PIP and MCP morning stiffness and joint swelling)
Pseudoneuropathic joints (<5% of pt, severe destructive arthropathy, no clear neuro disorder present, chondrocalcinosis on Xray_ |
| How is physical exam of CPPD? | vary depending on the form of CPDD
Acute pseudogout( an acutely inflamed joint with swelling, effusion, warmth, tenderness, and pain on range of motion
typically occurs in the knee but may be present in the wrists, shoulders, ankles, hands, and feet.)
Pseudo-osteoarthritis (Osteoarthritis like, sometimes with an unusual joint predilection If a patient has osteoarthritis involving the MCP joints and wrists, consider CPPD associated with an underlying metabolic disease.)
Pseudorheumatoid arthritis (rheumatoid arthritis with synovitis in a symmetrical, polyarticular pattern, especially involving the wrists and MCP joints.) |
| What are complications of CPPD? | Acute synovitis and degenerative arthtitis, joint destruction from neuropathic like arthropathy (rare), sometime invasive CPPD, coexistent infection, Crowned dens syndrome |
| How is dx of CPPD done? | Arthrocentesis (see calcium pyrophosphate in tissue/synovium, no positive birefringence by compensated polarized LM)
X ray (radio calcifications in knees, wrist, pubic symphysis and shoulders)
US (cartilagenous calcifications) |
| How is workup of CPPD? | WBC and ESR elevated, underlying metabolic disease, get serum Ca, P, Mg, ALP, iron workup, pseudogout (leukocytosis with left shift), crystals appear rhomboid difficult to see, If intracellular acute pseudogout may suggest it, aspiration we see WBC 10,000-50,000 90% neutrophils)
Radio (Hooklike osteophytes seen for hemochormatosis, pseudosteoarthritis and simple CPPD, US shows difference between gout and chondrolithiasis |
| What is the difference between gout and pseudo gout? | Crystal composition (Uric acid vs Calcium pyrophosphate)
Crystal shape (needle-like vs rhomboid)
Birefringent (negative vs weakly positive)
Most common affect 1st joint (MTP vs knee)
Radio (rat-bite erosion vs white lines of chondrolithiasis)
First line tx (both NSAIDs) |
| What is Ochronosis? | Bluish black discoloration of tissues, seen with alkaptonuria (rare autorecessive disorder of deficiency of homogentisic acid oxidase, so we get accumulation of homogentisic acid in tissues, involvement of pigmentation of chorndrocytes by IL6, tissues weakly brittle lead to chronic inflammation, black urine. |
