Objectives To evaluate the efficacy and safety of adrenocorticotropic hormone (ACTH) for the treatment of acute calcium pyrophosphate (CPP) crystal arthritis in hospitalized patients. Experimental data indicate that ACTH is not just a “steroid releasing” hormone but has an intrinsic anti-inflammatory effect related to its ability to bind and stimulate melanocortin receptors.
Methods We retrospectively identified 14 cases of acute CPP crystal arthritis where ACTH was used as first line treatment; the hospital medical files of these patients were fully reviewed. Data recorded were: 1) age, 2) sex, 3) admission and discharge diagnosis 4) history of major comorbidities that represent contraindications to non steroidal anti-inflammatory drugs (NSAIDs), steroids or colchicine use 4) site(s) of joint involvement, 5) presence of chondrocalcinosis on x-rays and 6) fasting glucose and potassium levels (where available) and blood pressure (BP) at baseline and the 1st and 2nd day following ACTH administration, in order to explore “steroid-related” metabolic side effects. All patients were subjected to arthrocentesis; diagnosis was verified by CPP crystal detection whereas synovial fluid cultures were negative. Response to treatment was defined as i) resolution of arthritis and ii) no use of steroids, NDAIDs, colchicine or analgesics for 4 days following the attack. Patients were treated with 1 mg of synthetic ACTH intramuscularly.
Results Patients had a mean ± SD age of 80.29 ± 3.87 years with equal gender distribution. All patients had at least one comorbidity that represents a contraindication to NSAIDs, steroids or colchicine use. The most common site of joint involvement was the knee (n=9), followed by the ankle (n=3), elbow (n=1) and wrist (n=1); in all cases the attack was monoarticular. The majority of patients (n=10) had a diagnosis of osteoarthritis. A dramatic response was seen in 13 patients with attenuation of signs of inflammation within 24 hours without the use of NSAIDs, colchicine or steroids. One patient had a partial response and received a second ACTH injection the day following the first injection; response with complete resolution of arthritis was seen. No patient suffered a rebound attack during hospitalization. No adverse events could be related to ACTH administration. Patients treated with ACTH showed a non statistically significant increase in fasting glucose the day following the injection compared to baseline (mean ± SEM: 153.70 ± 73.09 vs 130 ± 34.22 mg/dl, respectively, p=0.34, data available from 9 patients). BP and potassium levels remained stable the 1st and 2nd day following ACTH administration.
Conclusions This study provides evidence supporting the use of ACTH as first line treatment for acute CPP crystal arthritis in hospitalized patients; our data indicate that ACTH is effective and most importantly safe. The latter is of particular interest, since patients with acute CPP crystal arthritis are usually of advanced age and suffer from multiple comorbidities and are therefore poor candidates for NSAIDs, colchicine or steroid administration.
Disclosure of Interest None Declared