A practical approach to gout. Current management of an 'old' disease

Cardiotoxic changes of colchicine intoxication in rats: electrocardiographic, histopathological and blood chemical analysis

The microtubule inhibitor colchicine is cardiotoxic and is suggested to impair impulse formation and conduction. However, little is known about the electrocardiographic (ECG) changes induced by colchicine in experimental animals and the detailed pathogenesis of its cardiotoxicity. Therefore, we analyzed cardiotoxicity in colchicine-treated rats using electrocardiographic, histopathological and blood-chemistry approaches. A telemetry device for transmitting ECG data was implanted into male Crl:CD(SD) rats, and ECG tracings were obtained. At 6 weeks of age, 1.25 mg/kg colchicine was injected intravenously once daily for 2 consecutive days, and ECG waveforms and heart rate variability were analyzed. Furthermore, 1.25 mg/kg colchicine or vehicle was injected for 1 or 2 consecutive days in other rats at 6 weeks of age. One day after the final dosing, heart and blood samples were taken for histopathological and bloodchemical examination. ECG analysis revealed a prolonged RR interval, QRS duration, PR interval and QT interval. Heart rate variability analysis showed an increase in high frequency (HF) components as an index of parasympathetic nervous activity. In blood chemical examinations, colchicine induced high levels of parameters of cardiac injury and low levels and/or variations in Ca, inorganic phosphorus, potassium and chloride. Histopathologically, colchicine-treated rats showed eosinophilic granular degeneration and cytoplasmic vacuolation of ventricular myocardial cells but no remarkable change in the atrioventricular node. Not only blood chemical and histopathological changes but also ECG changes were induced in colchicine-treated rats, which indicated a decrease in myocardium excitability and conductivity, and these changes might be related to increased parasympathetic nervous activity and low blood Ca levels.

Advanced imaging in gout

OBJECTIVE

The purpose of this article is to describe the role of advanced imaging using ultrasound, CT, and MRI in the assessment and diagnosis of gout.

CONCLUSION

Dual-energy CT can quantitatively identify monosodium urate crystal deposits with high sensitivity and specificity within joints, tendons, and periarticular soft tissues. There are several characteristic ultrasound imaging findings, which include visualization of echogenic monosodium urate crystal deposition, tophus, and adjacent erosions. MRI is sensitive in showing soft-tissue and osseous abnormalities of gout, although the imaging findings are not specific. Gout commonly involves specific joints and anatomic structures, and knowledge of these sites and imaging appearances are clues to the correct diagnosis.

Tophaceous gout in the cervical spine

A 58-year-old woman with a three-year progressive history of chronic arthritis, had become disabled due to general malaise and fever. Her laboratory data revealed hyperuricemia and elevated levels of C-reactive protein. Neither rheumatoid factor nor anti-citrullinated peptide antibodies were present. We diagnosed her with tophaceous gout with uric crystalline revealed by the arthrocentesis of the elbow. (99m)Tc scintigraphy also disclosed a significant uptake in the cervical spine. The CT of the patient's cervical spine revealed significant bone erosion and destruction. We diagnosed the cervical involvement of gout based on the exclusion of infections and sarcoidosis. Rheumatologists should be aware of this rare association.

[A case of chronic tophaceous with a continuous polyarthritis and joint deformity caused by uncontrolled hyperuricemia]

A 56-year-old woman was admitted to our hospital in April 2007 due to a history of polyarthralgia. In 1999, She had been diagnosed as having gout by monoarthritis of the first metatarsophalangeal joint. She was treated with only cholchine. Subsequently she repeatedly got acute attack once a year. In 2006, episodic monoarthritis became to be continuous polyarthritis. Laboratory examination at admission showed remarkable hyperuricemia. At 3 day after hospitalization, she experienced acute attack and high fever. Diagnosis of chronic gout was confirmed by the identification of monosodium urate crystals in the synovial fluid. Her symptom improved by a treatment with dexamethasone 4 mg/day i.m. and cholchine, and did not experience acute attack for 5 months. We suggest that prophylactic administration of cholchine is beneficial in refractory chronic gout patient.

Therapeutic effects of xanthine oxidase inhibitors: renaissance half a century after the discovery of allopurinol

The prototypical xanthine oxidase (XO) inhibitor allopurinol, has been the cornerstone of the clinical management of gout and conditions associated with hyperuricemia for several decades. More recent data indicate that XO also plays an important role in various forms of ischemic and other types of tissue and vascular injuries, inflammatory diseases, and chronic heart failure. Allopurinol and its active metabolite oxypurinol showed considerable promise in the treatment of these conditions both in experimental animals and in small-scale human clinical trials. Although some of the beneficial effects of these compounds may be unrelated to the inhibition of the XO, the encouraging findings rekindled significant interest in the development of additional, novel series of XO inhibitors for various therapeutic indications. Here we present a critical overview of the effects of XO inhibitors in various pathophysiological conditions and also review the various emerging therapeutic strategies offered by this approach.

Gout: a clinical and radiologic review

Gout is a group of diseases characterized by arthritis and results from a disturbance of urate metabolism with the deposition of monosodium urate crystals in the joints and soft tissues. Often, but not invariably, the serum urate levels are elevated as a result of overproduction or underexcretion of uric acid. Clinical manifestations include acute and chronic arthritis, tophaceous deposits, interstitial renal disease, and uric acid nephrolithiasis. The diagnosis is based on the identification of uric acid crystals in joints, tissues, or body fluids. Acute episodes are treated with colchicine, NSAIDs, or steroids. Long-term management includes treatment with uricosuric agents or xanthine oxidase inhibitors.

Serum retinol, the acute phase response, and the apparent misclassification of vitamin A status in the third National Health and Nutrition Examination Survey

BACKGROUND

Serum retinol decreases transiently during the acute phase response and can thus result in misclassification of vitamin A status.

OBJECTIVE

Our objective was to determine the prevalence of acute phase response activation in a representative sample of the US population, identify the factors associated with this activation, and determine whether persons with an active acute phase response have lower serum retinol concentrations.

DESIGN

Data from the third National Health and Nutrition Examination Survey (NHANES III) were analyzed. A serum C-reactive protein (CRP) concentration >/=10 mg/L indicated an active acute phase response.

RESULTS

Mean serum retinol was lowest in subjects aged <10 y and increased with age. Concentrations were higher in males than in females aged 20-59 y. The prevalence of a CRP concentration >/=10 mg/L was lowest in subjects aged <20 y (</=4%) and increased with age to a maximum of nearly 15%. An elevated CRP concentration was 2.4-fold greater in females than in males aged 20-59 y. Serum retinol was lower in subjects with elevated CRP concentrations.

CONCLUSIONS

Serum retinol increases with age and males have higher mean values than do females aged 20-59 y. The prevalence of a CRP concentration >/=10 mg/L also increases with age, is 2-fold greater in females than in males aged 20-69 y, and is associated with common inflammatory conditions. Thus, inflammation appeared to contribute to the misclassification of vitamin A status in the NHANES III population, and serum CRP is useful in identifying subjects who may be misclassified.