this case report describes an acute reaction , thought to be vagally mediated , in two cats immediately following cystocentesis . both cats were being evaluated for feline idiopathic cystitis and developed bradycardia , hypersalivation , urination and weakness after a blind cystocentesis . a vagally mediated response may occur in cats after cystocentesis , which is a common procedure performed by veterinary professionals in cats this vagally mediated response to cystocentesis , though reported by word of mouth among veterinarians , has not been described in the literature . cystocentesis is a common medical procedure performed in veterinary hospitals to obtain urine samples for evaluation . it allows for obtaining a urine sample in a sterile fashion , which is preferred for urine culture evaluation . cystocentesis is also a practical way to obtain urine samples from animals that may not necessarily provide one on command or in a timely fashion when hospitalized , which is true in cats . complications associated with cystocentesis , though uncommon , have been previously described , and include laceration of the aorta or uroabdomen and peritonitis . cystocentesis can be a stressful procedure for cats as it may involve restraint in lateral or dorsal recumbency this case report describes two cats with suspected vagal reactions after routine cystocentesis was performed . a 4.17 kg 6-year - old male castrated domestic shorthair cat was presented for evaluation with a chief complaint of inappropriate urination . the owner reported pollakiuria and stranguria that had been going on for about 24 h. the cat had also vomited three times since urinary signs began . to the owner s knowledge , cystocentesis had not been previously performed on the cat . on presentation , the cat was quiet and responsive . physical examination revealed moderate periodontal disease and the cat was estimated to be about 5% dehydrated . the urinary bladder was medium sized ( about 4 cm ) and the cat was not assessed to be painful on abdominal palpation . the cat was placed in right lateral recumbency with minimal restraint and a blind cystocentesis was performed with a 1 inch 22 g needle . the first attempt , by a veterinary student , was unsuccessful and a second attempt was made by a veterinarian . after 2 ml of normal - appearing urine was obtained via cystocentesis , the cat vocalized and began voiding urine in a normal stream . the cat immediately became weak , exhibited hypersalivation and became tachypneic ( respiratory rate of 72 breaths per minute ) , which rapidly progressed to open - mouth breathing . an indirect blood pressure was obtained and was normal ( petmap ; cardiocommand ) , with an average systolic reading of 137 mmhg . flow - by oxygen was initiated at 5 l / min , while an abdominal focused assessment sonography for trauma ( fast ) scan was performed . thoracic fast scan did not reveal evidence of pleural effusion . supportive therapy consisted of oxygen support and observation . the bradycardia resolved to a heart rate of 180 beats per minute about 30 mins after the cystocentesis was performed . within the same time period , the open - mouth breathing , tachypnea , and hypersalivation resolved , and the cat s demeanor returned to normal . a complete blood count ( cbc ) and the cat was diagnosed with feline idiopathic cystitis ( fic ) and treated with 250 ml subcutaneous fluids ( plasma - lyte a ; baxter healthcare ) , buprenorphine ( buprenex , 0.01 mg / kg sublingually q8h ; hospira ) and robenocoxib ( onsior , 1.4 mg / kg po q24h ; novartis animal health ) . the owner elected not to pursue any additional diagnostics to evaluate the reasons for the previous vomiting . the cat was monitored in the hospital for 5 h after the event , and was assessed to be normal . follow - up evaluation 1 month later revealed no abnormalities , and the owner reported resolution of the inappropriate urination . a 3.84 kg 18-year - old female spayed domestic shorthair cat was presented for a recheck evaluation of hematuria that had been assessed and treated at our institution 4 months prior . at that time , physical examination revealed dental disease and a grade 3/6 parasternal systolic murmur . cbc , serum chemistry and urinalysis were performed , and there were no abnormalities noted . a urine sample obtained via the cat was treated supportively for a presumed diagnosis of feline idiopathic cystitis with buprenorphine ( buprenex , 0.01 mg / kg sublingually q812h ) and recommendations to increase water consumption . at the time of the recheck examination , the owner reported that the cat had been doing well at home and the hematuria had resolved . physical examination revealed scabs around the neck , missing upper molars and premolars , as well as a grade 3/6 parasternal systolic murmur . there was a large ( ~7 cm ) , soft and non - painful urinary bladder on abdominal palpation . the cat was restrained in lateral recumbency and a blind cystocentesis was performed using a 1 inch 22 g needle and normal - colored urine was collected . no complications occurred during the procedure . however , immediately following the cystocentesis , the cat vomited and defecated . the patient became tachypneic , which progressed to open - mouth breathing , and voided urine with evidence of gross hematuria . owing to the presence of the heart murmur and potential for heart failure , furosemide ( 3.26 mg / kg ) was administered intramuscularly and the cat was placed in an oxygen cage with a fraction of inspired oxygen of 40% . the open - mouth breathing resolved and the respiratory rate came down to 32 breaths per minute after 1 h. thoracic radiographs and echocardiogram were declined by the owner . a urinalysis performed on the urine sample obtained via cystocentesis revealed no abnormalities other than trace amounts of protein diagnosed via urine dipstick . the patient was discharged on the same day after being observed in the hospital for about 6 h. communications with the client 1 month after discharged revealed that the cat was doing well at home . adverse reactions following cystocentesis have been anecdotally reported in feline patients . reported clinical signs include collapse , lethargy , vomiting , defecation , hypersalivation , tachypnea and bradycardia . to our knowledge , this is the first case report describing this reaction in two cats . in this case report , both cats experienced a significant adverse event immediately following cystocentesis , which was thought to be vagally mediated based on the clinical signs associated with both events ( open - mouth breathing , hypersalivation , bradycardia and hematuria ) . both cats experienced a vasovagal response following the cystocentesis , sometimes referred to as cystocentesis shock. the vasovagal response described in human patients is characterized by an inappropriate combination of bradycardia and arterial vasodilation , resulting in cardiovascular collapse , syncope and , in some cases , cardiac arrest . the inappropriate bradycardia is due to the augmentation of vagal activity , while the arteriolar dilation is due to sudden cessation of sympathetic activity . the vasovagal reflex may develop as a result of relative or absolute loss of blood , but can also occur as a result of strong emotions , as can be seen with humans that experience a syncopal episode as a result of needle phobia during phlebotomy . both the sympathetic nervous system ( sns ) and the parasympathetic nervous system ( pns ) contribute to the regulation of various organs , including the urinary bladder , stomach , adrenal glands , pancreas and heart . most of the pns output occurs through the vagus nerve ( cranial nerve x ) , which supplies parasympathetic innervation to all the viscera of the thorax and abdomen . specifically , the urinary bladder is innervated by somatic ( pudendal nerve ) , sympathetic ( hypogastric nerve ) and parasympathetic ( pelvic nerve ) nerves . although stimulation of parasympathetic nerves innervating the bladder of cats has been reported , there has been no documented case of a vasovagal response . however , stress and/or painful stimuli are known triggers of the vasovagal response in humans . routine medical procedures can be stressful to cats , and the associated stress can produce periods of physiologic instability . as both cats had evidence of gross hematuria immediately following the cystocentesis ( even through the urine collected via cystocentesis had no evidence of gross or microscopic hematuria ) , it is possible that the needle insertion into the urinary bladder caused enough pain and/or trauma to the bladder mucosa to elicit a strong vagal response . in addition , both of these cats also presented with clinical signs potentially consistent with fic . it has been reported that cats with fic have increased catecholamine concentrations compared with normal cats , suggesting that cats with fic have increased sympathetic tone . however , it has also been suggested that continual agonist stimulation may result in desensitization and down - regulation of -2 receptors , which may reduce sympathetic tone and increase parasympathetic tone . it is possible that the combination of an already inflamed urinary bladder and the introduction of a needle was enough to stimulate a strong vagal response . this vagal response might explain the relative bradycardia , hypersalivation , sudden collapse and gastrointestinal signs seen in these cats . it is possible that cats with fic are at higher risk of developing a vasovagal response to cystocentesis . both cats also appeared to recover within 1 h of the adverse event , which is supportive of a transient vagal influence as opposed to an ongoing pathologic event . both cats responded well to supportive care , which consisted of oxygen therapy and observation . a blood pressure measurement was obtained on cat 1 , which revealed that the cat was normotensive . additional therapy , including the administration of an anticholinergic agent such as atropine was deemed not necessary . while a blood pressure measurement was not obtained on cat 2 , the cat was closely monitored in the intensive care unit and determined to have strong femoral pulses . although thoracic radiographs and echocardiogram were not performed to rule out congestive heart failure , the administration of furosemide was likely not necessary . both cats returned to normal about 3045 mins after the initial event and they were discharged on the same day of presentation . this case report documents the first report of probable vasovagal reaction in cats following cystocentesis . conclusions are limited owing to the rare occurrence and retrospective nature of this case report . if a vagal response is observed , therapeutic considerations should include monitoring of the cat until clinical signs resolve , as well as provision of oxygen therapy . in extreme cases of severe bradycardia and/or hypotension , atropine and intravenous fluid therapy
case summarythis case report describes an acute reaction , thought to be vagally mediated , in two cats immediately following cystocentesis . 
 both cats were being evaluated for feline idiopathic cystitis and developed bradycardia , hypersalivation , urination and weakness after a blind cystocentesis . 
 both cats recovered uneventfully with supportive care.relevance and novel informationa vagally mediated response may occur in cats after cystocentesis , which is a common procedure performed by veterinary professionals in cats . 
 this response may be very profound and dramatic . 
 affected cats will likely make an uneventful recovery . 
 this vagally mediated response to cystocentesis , though reported by word of mouth among veterinarians , has not been described in the literature . 
 this is the first documentation of its occurrence in cats .