Abstract
The metabolic diseases gout and calciumpyrophosphate deposition (CPPD) (formerly:
chondrocalcinosis/pseudogout) are crystal arthropathies which are caused by crystals
in synovial fluid and in the case of gout also in periarticular structures. Today,
in particular gout is considered as an auto-inflammatory process since phagocytosis
of monosodium urate crystals by monocytes/macrophages results in the activation of
the innate immune system by activation of the NRLP3-Inflammasome and consecutive secretion
of the key cytokine interleukin-1ß and other pro-inflammatory cytokines. The prevalence
of both crystal arthropathies rises with increasing age of patients. Most often they
present clinically as an acute monarthritis of different locations. Beside typical
clinical presentation, performance of ultrasonography, conventional X-Ray of joints
and under special circumstances dual-energy-computer tomography could be also helpful
diagnostic tools. There are EULAR guidelines describing the diagnostic algorithm for
making right diagnosis. The arthrocentesis with microscopic detection of crystals
is established diagnostic gold standard. Whereas crystals of monosodium urate could
be very clearly be seen as relatively large intra- and extracellular needles with
a strong birefringence in polarized light microscopy the detection of CPPD-crystals
is more difficult. Those crystals are much smaller, showing weaker birefringence and
are sometimes only seen with ordinary light microscopy. As both crystal diseases are
mediated by IL-1 driven processes, the therapeutic intervention first target the acute
inflammation consisting in colchicine, NSAIDs and glucocorticoids. Secondarily, in
gout there are well established causal therapies to lower effectively serum urate
levels below the target of 6 mg/dL (360 µmol/l). Unfortunately, those causal therapeutic
options are still lacking in CPPD.
Der Gichtanfall und die akute Calciumpyrophosphat-Dihydrat (CPPD) -Arthritis (früher
als Pseudogicht bezeichnet) sind hochentzündliche, meist akut auftretende Arthritiden.
Klinisch manifestieren sie sich überwiegend als akut auftretende Monarthritis, wobei
die CPPD-Arthritis eher größere Gelenke betrifft. Da beide Erkrankungen auch koinzident
auftreten können, kann die differenzialdiagnostische Unterscheidung schwierig sein.
Schlüsselwörter
Kristallarthropathien - Gicht - Chrondrokalzinose - Calciumpyrophosphat-Arthropathie
- Serumharnsäure
Key words
crystal arthropathies - gout - chondrocalcinosis - calciumpyrophosphat deposition
(CPPD) - serum uric acid
