Mecanismos de formação dos urólitos em cães e gatos

Uroliths may be composed of organic and mineral compounds. There are multifactorial mechanisms involved in urolith formation. However, the complete pathophysiology is yet not fully elucidated since it involves epidemiological, genetic, dietary, infectious and racial factors, among others. Urolithiasis has been reported in humanity since 8,000 B.C and is very common, not only for humans but for dogs and cats. Classification is based on the chemical composition of the calculus, which can be formed of mineral compounds such as struvite (magnesian ammonium phosphate), calcium oxalate, calcium phosphate and silica, or organic compounds such as ammonium urate, cystine and xanthine. Diagnosis involves carrying out laboratory and imaging tests, and the chemical and physical analysis of the calculus. Some studies have been carried out to clarify the causes of urolith formation, and there are seven theories that highlight the risk factors associated with their development: crystallization theory; inhibitor deficiency theory; matrix theory; colloidal theory; ionic theory; fixed particle theory and, finally, renal cell injury theory. Knowing these theories aids in the correct understanding of the pathophysiology, but it is mostly necessary that we understand the animal and the environmental factors together for a better treatment approach and prevention. Another important information is that uroliths are a secondary manifestation to the existing problem, and their removal hinges on ruling out the primary cause. The main goal to be achieved is reducing urolith occurrence and minimizing unnecessary invasive procedures by identifying urolith formation mechanisms and, consequently, their risk factors to provide correct treatment for each type of urolith formed. Os urólitos podem ser formados por compostos orgânicos e minerais e possuem mecanismos de formação multifatoriais e complexos. A fisiopatogenia não está totalmente elucidada e envolve fatores epidemiológicos, genéticos, dietéticos, infecciosos, raciais, dentre outros. No trato urinário essa enfermidade é denominada de urolitíase e está presente na humanidade desde 8.000 a.C. A classificação é baseada na composição química do cálculo, podendo ser formado por compostos minerais como estruvita (fosfato de amônio magnesiano), oxalato de cálcio, fosfato de cálcio e sílica ou por compostos orgânicos como urato de amônio, cistina e xantina. O diagnóstico envolve a realização de exames laboratoriais, de imagem e a análise