Chronic Vomiting in Cats: Etiology and Diagnostic Testing

Chronic vomiting in cats is a common presenting problem seen in veterinary practice today. The initial step when presented with a vomiting patient is to differentiate between vomiting and regurgitation or dysphagia. There are numerous causes for chronic vomiting in cats, and therefore a detailed and comprehensive patient history and a systematic diagnostic approach are key steps in determining the cause for vomiting and the most appropriate treatment plan. Common causes for chronic vomiting in cats may include inflammatory bowel disease, food allergy, gastrointestinal motility disorders, neoplasia, and extra-gastrointestinal diseases, such as renal disease, hepatobiliary disease, and hyperthyroidism.

Canine struvite urolithiasis

Struvite calculi, composed of magnesium ammonium phosphate, have existed for thousands of years in human medicine and are a leading cause of calculi in companion animals. Struvite stones have also been called urease, infection-induced, phosphatic, and triple phosphate stones. They are the most common uroliths in dogs, in which most cases of struvite urolithiasis are associated with infection. Management of struvite urolithiasis requires a multimodal approach that addresses the presence of the urolith(s) and associated infection while identifying risk factors that predispose to the development of infection.

CT and MRI evaluation of skull bones and soft tissues in six cats with presumed acromegaly versus 12 unaffected cats

Feline acromegaly is predominantly caused by an adenoma of the pituitary gland, resulting in excessive growth hormone and insulin-like growth factor (IGF-1) secretion. In advanced cases, cats will display prominent facial features and upper airway congestion secondary to bony and soft tissue proliferation. The purpose of this study was to describe CT and MRI characteristics of soft tissues and skull bones in six cats with presumed acromegaly and to compare findings with those observed in 12 unaffected cats. In the five acromegalic cats with CT or MRI evidence of a pituitary tumor, frontal bone thickness was greater than age-matched controls with and without a history of upper airway disease. These five cats also had evidence of soft tissue accumulation in the nasal cavity, sinuses, and pharynx. One cat with insulin-resistant diabetes mellitus, elevated IGF-1, and a normal pituitary size did not have evidence of frontal bone thickening or upper airway congestion.

Methods of urolith removal

Multiple techniques exist to remove uroliths from each section of the urinary tract. Minimally invasive methods for removing lower urinary tract stones include voiding urohydropropulsion, retrograde urohydropropulsion followed by dissolution or removal, catheter retrieval, cystoscopic removal, and cystoscopy-assisted laser lithotripsy and surgery. Laparoscopic cystotomy is less invasive than surgical cystotomy. Extracorporeal shock wave lithotripsy can be used for nephroliths and ureteroliths. Nephrotomy, pyelotomy, or urethrotomy may be recommended in certain situations. This article discusses each technique and gives guidance for selecting the most appropriate technique for an individual patient.

Feline struvite urolithiasis

Feline urolithiasis represents 15% of all cases of nonobstructive lower urinary tract disease in cats. Approximately 50% of feline uroliths are composed of struvite. Struvite urolithiasis commonly recurs, but optimal management may decrease its frequency. The pathophysiology and management of struvite urolithiasis are different in cats and dogs. This article focuses on struvite urolithiasis in cats, highlighting important aspects of pathophysiology, treatment, and prevention.

Calcium oxalate urolithiasis

Calcium oxalate (CaOx) uroliths are one of the most common urolith types in dogs, cats, and humans. Many factors predispose animals to CaOx uroliths, including breed, old age, obesity, male sex, being neutered, and certain diseases. Because there are no effective strategies for medical dissolution of these uroliths, management should focus on physical removal (by surgical or nonsurgical methods) and prevention, especially in patients with recurring uroliths, high-risk breeds, and animals with predisposing diseases. Prevention focuses on diet modification, primarily to increase water intake, and the appropriate use or avoidance of specific medications.

Urate urolithiasis

Urate uroliths belong to the purine family of uroliths and are the third most common urolith type in dogs and cats. In dalmatians, an autosomal recessive trait is responsible for hyperuricosuria and a predisposition to urate urolithiasis. In other dog breeds and in cats, urate uroliths are predominantly associated with liver disease, specifically portosystemic vascular anomalies. Idiopathic urate uroliths may occur in animals without liver disease. Ammonium urate uroliths are most common. Urate uroliths are amenable to medical dissolution. This article reviews the pathogenesis and management of urate urolithiasis.

Diagnosis of urolithiasis

Diagnostic imaging is usually required to determine the presence of urolithiasis. Double-contrast cystography is more accurate than survey radiography and approximately as accurate as ultrasonography. Knowledge of the mineral composition of calculi helps direct appropriate management of urolithiasis, and signalment can help predict composition with about 70% accuracy. In cats, about half of cystic calculi are struvite and half are calcium oxalate; most nephroliths and ureteroliths are calcium oxalate. In female dogs, struvite uroliths are the predominant type found in the bladder. In male dogs, breed plays a strong role in prediction of bladder urolith type. It is difficult to predict the composition of nephroliths and ureteroliths based on signalment alone in dogs. Urinalysis and imaging findings can help in predicting urolith composition, although chemical analysis is necessary for definitive diagnosis.