Tomcat Urethral Obstruction Treatment Overview

By Lisa Murphy DACVECC

Causes of a urethral obstruction (UO) are varied but include idiopathic obstruction (which in more recent studies was > 50% of cases evaluated) and less commonly, uroliths and urethral plugs. Much research has also been done into the treatment of urethral obstruction in cats secondary to Feline Lower Urinary Tract Disease (FLUTD)/Feline Idiopathic Cystitis. Aside from actually removing the obstruction in the short term, few treatments have been proven to significantly reduce recurrence with upwards of 20% of cats experiencing a recurrence within 6 months. 

Here I summarise some of the common treatments. As always, please feel free to comment or to email me with questions (lisamurphyirish@gmail.com).

Intravascular volume resuscitation

Cats with urethral obstruction presenting in cardiovascular collapse require ‘shock doses’ of intravenous fluids (e.g. 10-20 ml/kg bolus followed by constant reassessment of the patient’s perfusion status repeating boluses as needed).

Studies looking at the use of different types of fluids, more specifically 0.9% sodium chloride (saline) vs. Normosol R (similar to buffered LRS or Hartmann’s solution), did not show any difference in outcome or clinically significant reduction in plasma potassium levels. Cats given NormR had a more rapid normalisation of their acid-base balance. For more on this topic see this podcast episode.


Hyperkalemia

Hyperkalemia occurs commonly in cases with severe obstruction from urine retention. Reduced glomerular filtration rate with secondary acute kidney injury (AKI) from the initial UO may also promote hyperkalaemia. These patients can present in shock-like states from severe hyperkalemia.

Typically, this is recognised by inappropriately severe bradycardia and cardiac dysrhythmia. Common dysrhythmias include atrial standstill and ventricular premature complexes. There is no set blood potassium level at which dysrhythmias will occur – although they are more common at levels > 8.5 mmol/l. Treatment is usually recommended above this level although some cats will not show clinically significant signs of hyperkalaemia even at this level. It is important to treat each patient as an individual.

Treatment options include:

  • Intravenous fluid therapy: improves renal perfusion and renal excretion of potassium; dilutes potassium in the extracellular compartment.
  • Calcium gluconate (0.5-1 ml/kg IV over 15 mins): can temporarily (approximately 20 minutes) reduce the cardiotoxic effects of hyperkalemia. It does not reduce plasma potassium levels and needs to be followed up with definitive management.
    • [S Jasani: the risk-benefit profile for the use of calcium gluconate in cats with clinically significant hyperkalaemia is very favourable in my opinion. I encourage a liberal approach to administer this therapy, potentially more than once.]
  • Dextrose (glucose) (0.5-1 ml/kg IV) and insulin (0.5 u/kg regular (neutral, soluble) insulin) to drive potassium into the intracellular compartment. Although both substances have a fast onset of action, use of insulin requires close monitoring of blood glucose over subsequent hours.

Decompressive cystocentesis

There has been much controversy about the safety of this procedure in these patients and until recently I definitely was in the camp of never doing this. Nowadays I will discuss the potential risks of this procedure with owners where I consider the procedure necessary.

Advantages of this procedure include:

  • Buying time for the patient by helping correction of the electrolyte derangements at least temporarily until a more definitive treatment can be performed
  • Potentially may help with unblocking
  • Rapid relief of symptoms
  • Need for minimal to no sedation
  • Helping to restore glomerular filtration which helps reduce worsening kidney injury

Potential risks of this procedure include:

  • Bladder rupture. However, in a retrospective study of 47 cats who had this procedure performed, no cat developed a ruptured bladder. An indwelling catheter was placed following decompressive cystocentesis in these cats and they were managed as standard thereafter.
  • Uroabdomen. A published study evaluated the use of repeat decompressive cystocentesis in cases where owners did not have the finances to pursue indwelling urinary catheter placement. Of the 15 cats evaluated, 73% were discharged, some of which had more than ten cystocentesis procedures performed. Of the non-survivors, three did develop uroabdomen and one haemoabdomen. Non-survivors also tended to have higher creatinine and required more frequent cystocentesis so perhaps this procedure should be avoided in sicker cats.
    • [S Jasani: information from this study has been shared here as it relates to the topic under discussion. However, I personally have very serious welfare concerns about this study protocol and remain to be convinced that an alternative more patient-friendly yet affordable protocol could not have been implemented.]

[S Jasani: as with Lisa, I do not promote the use of decompressive cystocentesis as first-line treatment. If performed, please be sure to drain the bladder as fully as possible to achieve maximum benefit possible.]

Catheter types and size, does it matter?

Is there a perfect catheter? The short answer is we don’t know. Each type of catheter has their own advantages and disadvantages.

  • Polyprolylene (or ‘Tom cat’) catheters are one of the more rigid options. They can help relieve the obstruction but also have higher risks of urethral trauma. They are likely uncomfortable for the cats if they are left indwelling.
  • Polyvinvyl (red rubber) catheters are commonly placed after the obstruction is relieved. They are much less irritant and offer more comfort for the cat.
  • More recent is the ‘Slippery Sam’ or polytetrafluroethylene which is very useful for unblocking without causing too much irritation to the urethra. However, it only comes in one size (3.5fr) and one length. Furthermore, the connection apparatus for this can be difficult and come apart easily. Please note that while we know some people still do this, some years back the manufacturers changed their recommendation to say that these catheters should not be left indwelling.

As far as catheter size, the jury is also still out. The 5fr catheter has the potential benefits of less luminal obstruction from clots, less likelihood of the cat urinating around it, and easier flushing of saline. However, one study looking at the use of 3.5fr and 5fr urethral catheters showed higher reobstruction rates with 5fr catheters within 24 hours (19% with 5fr vs. 6.7% with 3.5fr). This study was retrospective so the effects of different aetiologies of UO and differences in disease severity are difficult to interpret.

Finally, there is the question of how long to leave an indwelling catheter in place. In general, I would recommend leaving it in place at least until the cat’s blood work abnormalities have resolved and the urine grossly looks clear. No benefit has been proven on whether to leave it in for 24 or 48 hours.

Antibiotics

Depending on the study you read, bacteriuria has been shown in anywhere from < 2% up to 40% of cats with UO. What is known is that ‘prophylactic’ antibiotics do not prevent the development of urinary catheter-associated infections. In general, the younger a UO patient the less likely they have an infectious cause or component although they may develop one while the catheter is indwelling. Urine microbiology could be considered at the time of catheter removal or 3 days post removal. The practice of submitting the tip of the catheter for microbiology is also difficult to recommend because the tip has a high contamination rate which could cause false positives.

Urethral relaxants 

Medications most commonly used for this include acepromazine, phenoxybenzamine and prazosin which mainly function via alpha-1 antagonism leading to smooth muscle relaxation. Since smooth muscle is only present in the proximal third of the penile urethra these relaxants may not be very effective. One study showed a possible benefit of prazosin vs. phenoxybenzamine with lower recurrence of UO rates. A more recent study showed no beneficial effect of prazosin vs. placebo for the incidence of recurrent UO. 

Anti-inflammatories

Several anti-inflammatories have been studied for UO. Cats given prednisolone vs. a placebo did not show any improved survival. More recently, a study evaluating the use of meloxicom in cats with UO showed no difference in recurrence of UO or recovery from clinical signs compared to cats given a placebo. At this time, there’s no evidence showing a reduction in recurrence of UO with the use of anti-inflammatories. Intravesicular administration of pentosan sulphate, which is a glycosaminoglycan, also did not result in reduced recurrence or clinical signs.

Amitriptyline 

Amitriptyline is a tricyclic antidepressant which has anticholinergic, anti-histaminergic, sympatholytic, analgesic and anti-inflammatory properties. It has been used for human interstitial cystitis cases. Some studies have been performed evaluating this drug in non-obstructive FLUTD cases and have not shown any improvements. In one study, it may have increased the risk of FLUTD recurrence.

Post-obstructive diuresis

Post obstructive diuresis is an uncommon phenomenon that can occur in these patients. It may occur due to several factors including:

  • accumulation of osmotically active substances in the blood
  • tubular epithelial dysfunction
  • medullary washout
  • antidiuretic hormone dysfunction
  • increased natriuretic factors accumulating during obstruction 

Typically it is recognised by increased urine production (> 2ml/kg/hr). In one study, it tended to occur within 6 hours of resolution of the UO via a urinary catheter.  This study also showed cats with an admission pH of < 7.35, hyperglycaemia, hyperosmolality and azotaemia were more likely to experience this phenomenon. In some cases, the diuresis can last several days (one cat in the aforementioned study experienced it for 84hr).

Post-obstructive diuresis can lead to dialysis disequilibrium syndrome which is characterised by neurological symptoms from rapid decreases in peripheral osmolality. As the osmolality decreases, cerebral oedema occurs leading to an increase in intracranial hypertension (ICH).   Symptoms can range from vomiting and lethargy to more severe signs including seizures, obtundation and cardiac dysrhythmias. Should neurological signs occur, administration of a hyperosmolar osmotic agent (mannitol/hypertonic saline) is recommended for the ICH. Ideally one would also slow the decrease in osmotically active solutes (BUN in particular) although this can be difficult to achieve in these patients. 

Recurrence

In general, recurrence rates are anywhere between 20-45% in the first few months post-obstruction. Factors that may affect recurrence include the use of a 5fr urethral catheter and use of phenoxybenzamine but not the duration of catheterisation, administration of antimicrobials, use of pain medications or presence of an infection at admission. Independently, only increasing dietary water content was associated with decreased recurrence.

[S Jasani: the emphasis in this paragraph on recurrence should very much be on ‘…that MAY affect recurrence’. While Lisa kindly gives up her time to write these blogs posts, she is not able to simultaneously provide full evidence-based medicine critiques of the references listed. Type of study, methodology, sample size, size of any effect reported, etc. all need to be considered before drawing conclusions that may affect your personal clinical practice.]

References:

Kruger, J.M., Conway, T.S., Kaneene, J.B., Perry, R.L., Hagenlocker, E., Golombek, A. and Stuhler, J., 2003. Randomized controlled trial of the efficacy of short-term amitriptyline administration for treatment of acute, nonobstructive, idiopathic lower urinary tract disease in cats. Journal of the American Veterinary Medical Association, 222(6), pp.749-758.

Ostroski, C.J. and Cooper, E.S., 2014. Development of dialysis disequilibrium‐like clinical signs during postobstructive management of feline urethral obstruction. Journal of veterinary emergency and critical care, 24(4), pp.444-449.

Hetrick, P.F. and Davidow, E.B., 2013. Initial treatment factors associated with feline urethral obstruction recurrence rate: 192 cases (2004–2010). Journal of the American Veterinary Medical Association, 243(4), pp.512-519.

Cooper, E.S., 2015. Controversies in the management of feline urethral obstruction. Journal of Veterinary Emergency and Critical Care, 25(1), pp.130-137.

Reineke, E.L., Thomas, E.K., Syring, R.S., Savini, J. and Drobatz, K.J., 2017. The effect of prazosin on outcome in feline urethral obstruction. Journal of Veterinary Emergency and Critical Care.

Dorsch, R., Zellner, F., Schulz, B., Sauter-Louis, C. and Hartmann, K., 2016. Evaluation of meloxicam for the treatment of obstructive feline idiopathic cystitis. Journal of feline medicine and surgery, 18(11), pp.925-933.

Osborne, C.A., Kruger, J.M., Lulich, J.P., Johnston, G.R., Polzin, D.J., Ulrich, L.K. and Sanna, J., 1996. Prednisolone therapy of idiopathic feline lower urinary tract disease: a double-blind clinical study. Veterinary Clinics: Small Animal Practice, 26(3), pp.563-569.

Delille, M., Fröhlich, L., Müller, R.S., Hartmann, K. and Dorsch, R., 2016. Efficacy of intravesical pentosan polysulfate sodium in cats with obstructive feline idiopathic cystitis. Journal of feline medicine and surgery, 18(6), pp.492-500.

Francis, B.J., Wells, R.J., Rao, S. and Hackett, T.B., 2010. Retrospective study to characterize post-obstructive diuresis in cats with urethral obstruction. Journal of feline medicine and surgery, 12(8), pp.606-608.

Monthly Journal Round-Up - January 2018

Thanks as always to Lara Brunori DVM CertAVP MRCVS

Clinical studies:

Retrospective:

  • Binvel, M. et al. (2017) ‘Endoscopic and surgical removal of oesophageal and gastric fishhook foreign bodies in 33 animals’. Journal of Small Animal Practice,    doi: 10.1111/jsap.12794 (Early view)
  • Klainbart, S., et al. (2017) ‘Retrospective evaluation of 140 dogs involved in road traffic accidents’. Veterinary Record doi: 10.1136/vr.104293 (Early view)
  • Hernon, T. et al (2018) ‘A retrospective study of feline trauma patients admitted to a referral centre’. Journal of Small Animal Practice, doi: 10.1111/jsap.12815  (Early view)
  • Lennon, E. M. et  al. (2018) ‘Urine sodium concentrations are predictive of hypoadrenocorticism in hyponatraemic dogs: a retrospective pilot study’. Journal of Small Animal Practice, doi: 10.1111/jsap.12792 (Early view) 
  • Brisson, B.A. et al. (2018) ‘Risk factors and prognostic indicators for surgical outcome of dogs with esophageal foreign body obstructions’. Journal of the American Veterinary Medical Association, 252(3), pp. 301-308. 

Clinical case report: 

Barrand, K.R. (2018) ‘A case of canine intestinal obstruction due to ingestion of a superabsorbent polymer bead’ Journal of Small Animal Practice, doi: 10.1111/jsap.12812 (Early view)

Others:

Book review:

Hill, C. (2018) ‘Small Animal Emergency and Critical Care’ Veterinary Record 182(1), p. 27.

Pick of the Month

As voted for by members of our private Facebook group.

A retrospective study of feline trauma patients admitted to a referral centre

Hernon, T. et al (2018) Journal of Small Animal Practice, doi: 10.1111/jsap.12815  (Early view)

Trauma patients are a common presentation in both first opinion and referral veterinary practices. 

This study aims to: 

  • Document the initial management of trauma patients in primary care practices
  • Identify prognostic indicators for feline trauma patients 
  • Give recommendation for initial management of feline trauma patients 
  • 185 cats were enrolled in the study. The population consisted of cases seen in primary care practices for injuries due to traumatic events, then referred as emergencies to North-West Veterinary Specialists (Cheshire, UK). 

The authors classified patients according to a previously described  Severity Score (SS) system (Rochlitz, 2004).

Main findings: 

  • RTA was the most common cause of trauma (56%) followed by unknown origin (27%), falls (10%) and dog attacks (3%)
  • According to the referring veterinary surgeons (RVSs) 35% of cats were in circulatory shock, 45% received antibiotics prior to referral, 72% were administered NSAID either alone or in combination with opioids and 4% received corticosteroids
  • SS4 cats were the most frequently referred cases (nearly 50%) followed by SS3 (28%) and SS5 (21%)
  • The length of hospitalisation increased with SS with an overall mean time of 7 days 
  • 33% of the cases developed complications during hospitalisation, the more common of which were: sciatic nerve dysfunction (10%), tissue necrosis (4%) and urinary incontinence (3%)
  • Cats involved in RTAs had a higher rate of complications and mortality compared to other traumatic events
  • 12% of cats did not survive to discharge - 54% were euthanised and 91% were patients presenting with multiple injuries 
  • Mortality rate increased with increasing SS, with SS5 having a 43% rate of death compared to 3% for both SS3 and SS4
  • 21% of cats initially diagnosed with circulatory shock by the RVS died vs 7% of those who were not

Conclusions: 

  • An injury based scoring system might be useful in the initial assessment of cats following a traumatic event and could provide some prognostic indications regarding mortality in these patients
  • The duration of hospitalisation was closely related to SS, this may be useful when discussing expectations and financial commitments with owners
  • Early identification and stabilisation of circulatory shock is a key step to improve survival in trauma patients prior to referral, however clear guidelines regarding resuscitation end-points are still lacking
  • Analgesia was widely used by RVSs, however, the administration of NSAID in potentially haemodynamically unstable patients was also very frequent, furthermore, some RVSs still used corticosteroids in these cases. 

Limitations:

  • Lack of standardised treatment protocols prior to referral 
  • No unanimous definition of circulatory shock amongst RVSs
  • Variability in amount and thoroughness of clinical data provided by RVSs prior to referral 
  • Potential population bias due to intermediate SS being more likely to be referred than very low or very high SS
  • Definition of mortality was limited to discharge without any follow-up available and included euthanised patients 

Reference:

Rochlitz , I. ( 2004 ) ‘Clinical study of cats injured and killed in road traffic accidents in Cambridgeshire'. Journal of Small Animal Practice 45(8), 390 - 394.

For a copy of any of the papers mentioned in this post (personal education purposes only), including details of the scoring system, please email lara.brunori@gmail.com.

Anaphylaxis Refresher

By Lisa Murphy DACVECC

Overview 

Anaphylaxis is a common presenting complaint in small animal practice that requires prompt recognition and treatment for a successful outcome. Common definitions of anaphylaxis include:

“A severe, potentially fatal, systemic, immediate hypersensitivity reaction most commonly caused by the IgE-mediated immunologic release of mediators from mast cells and basophils”. 

Types

There are several categories of anaphylactic reactions although the clinical signs are similar and difficult to differentiate between each type:

  1. Immunologic IgE-mediated (e.g. insect stings, reptile venom, food, medications)
  2. Immunologic non-IgE mediated (e.g. IV immunoglobulins) 
  3. Non-immunologic (cold, water, exposure, some chemotherapeutic agents)

The classic pathway for anaphylaxis involves initial exposure to an antigen resulting in sensitization of mast cells. Repeat antigen exposure leads to the release of IgE, activation of mast cells, and release of multiple mediators including histamine, heparin, tryptase, kallikreins, proteases and proteoglycans among others. These mediators lead to vascular permeability and vasodilation which cause hypotension and other signs.

Clinical Signs

Clinical signs of anaphylaxis can vary with different species. In general the more rapid the signs the more severe the symptoms. In dogs, common manifestations include dermal and gastrointestinal signs; respiratory distress is more common in cats.

  • Dermal: erythema, urticaria, angioedema 
  • Gastrointestinal: nausea, vomiting, diarrhoea
  • Cardiovascular: tachycardia, hypotension, dysrhythmia
  • Respiratory: nasal congestion, stridor, dyspnea, bronchospasm, tachypnea 
  • Neurologic: weakness, seizures 
  • Ocular: pruritis, lacrimation 
A cat with anaphylaxis (Lisa Murphy)

A cat with anaphylaxis (Lisa Murphy)

Lily

Let’s meet Lily who is a 4-year old female spayed Yorkshire terrier (5 Kg). She presented with acute onset collapse after a walk. Soon after she developed vomiting and diarrhoea and became minimally responsive. Lily’s carers had witnessed her ingesting a bee. 

Physical exam findings: 

Major systems (primary survey)

  • Cardiovascular:
    • Heart rate: 160 bpm
    • Mucous membranes: light pink, CRT 1sec 
    • No murmur, tachycardic with poor femoral pulses
  • Respiratory:
    • Rate > 60 breath per minute with increased effort, stridorous 
    • Thoracic auscultation: increased bronchovesicular sounds bilaterally
  • Neurological:
    • Dull mentation, non-ambulatory x4

Secondary survey:

  • Temp 36.6⁰/98.0F
  • Abdominal palpation: soft, not distended
  • Rectal: diarrhoea, hematochezia 

Diagnostics

Minimum and extended database as indicated and routine for emergency patients.

Full blood work is recommended at the appropriate time for patients with severe anaphylaxis.
Potential changes include:

  • Elevations in liver enzymes (especially ALT)
  • Azotemia (pre-renal or renal)
  • Hemoconcentration
  • Coagulopathy
  • Thrombocytopenia

Thoracic radiographs are non-specific. In dyspneic animals, they may show an interstitial or alveolar lung pattern and/or microcardia.

If available, abdominal ultrasonography can be used to evaluate the gallbladder in dogs. One reference suggests that gallbladder wall edema may be over 90% specific for anaphylaxis secondary to hepatic venous congestion (Quantz et al, 2009). There are no studies evaluating if this occurs in cats.

 
Gallbladder wall edema in a dog (Lisa Murphy)

Gallbladder wall edema in a dog (Lisa Murphy)

 

Diagnostics were performed on Lily which revealed the following abnormalities:

Hematology:

  • Hematocrit (HCT) 60% (35-55%)
  • White blood cell count (WBCC) 16,500 (5000-16,700)
  • Platelets 100,000 (148,000-480,000)

Chemistry:

  • ALT 500 (10-125)
  • ALP 350 (23-212)
  • Total bilirubin (Tbili) 0.5 (0.1-0.6)
  • BUN 80 mg/dL (5-35) [28.57 mmol/L (1.79-12.5)]
  • Creatinine 3.0 (0.5-1.8) [265.26 umol/L (44.21-159.16)]
  • Glucose 56 mg/dL (80-150) [3.1 mmol/L (4.44-8.33)]

Thoracic radiographs: no cardiomegaly, mild bronchointerstitial pattern
Point of care ultrasound:

  • Abdominal: no ascites, gallbladder wall edema suspected
  • Thoracic: no free fluid 

Blood pressure (via non-invasive Doppler): 50 mmHg 

Considering the above diagnostics and Lily’s physical exam findings, her problem list could include the following:

  • Shock
  • Dyspnea
  • Hypotension
  • Vomiting, diarrhoea
  • Hypoglycemia
  • Elevated liver enzymes
  • Azotemia
  • Hemoconcentration
  • Dull mentation

Treatment

There are several treatment options for anaphylaxis but few are well-supported by evidence of significant patient benefit. Many of the problems treating anaphylaxis stem from the fact the signs are secondary to multiple mediators, not just histamine.

The hypotension seen in severe anaphylaxis should be addressed with appropriate fluid resuscitation – 90ml/kg in dogs, 60ml/kg in cats, given in aliquots with a constant reassessment of the patient’s clinical signs.

However fluid therapy alone is not sufficient in severe cases.

Epinephrine (adrenaline): 

This is a first-line treatment and the only medication that has proven a benefit. It is typically reserved for severe cases.

  • Benefits of administration include a reduction in the further release of histamine and other anaphylactic mediators from mast cells; and, increased cardiac output via cardiac β1 adrenergic effects and vasoconstriction via α1 vascular effects.
  • Side effects following rapid administration include tachycardia, tremors and anxiety
  • Route of administration: continuous intravenous infusion is the preferred route of treatment in cases of severe anaphylaxis. Subcutaneous dosing should be avoided due to unpredictable effects and delayed absorption via the skin in these patients.

Dose/route:

  • 2.5-5mcg/kg IV, 10mcg/kg IM
  • 0.05mcg/kg/min IV via CRI

Other therapies:

Antihistamines: 

Histamine concentrations peak at the onset of anaphylaxis but quickly return to normal
Little evidence supports the use of pre-treatment with anti-histamines to prevent anaphylaxis although they are a very well tolerated medication
Antihistamines can be effective for localized/dermal allergic reactions and may reduce gastric acid secretion

Diphenhydramine: 2-4mg/kg IM, PO q 8-12h
Ranitidine:

  • 2mg/kg PO q8-12h (dogs)
  • 3.5mg/kg PO q 12h (cats)

Glucocorticoids:

Due to the delayed onset of their beneficial effects (typically 4-6 hours after administration) they are not considered a first line drug
Benefits lie in the downregulation of the late eosinophilic inflammatory response preventing biphasic anaphylaxis
Pre-treatment with glucocorticoids will be unlikely to prevent anaphylaxis and could theoretically blunt the physiologic response
Dexamethasone: 0.1-0.5mg/kg IV

Bronchodilators:

Selective β2 adrenergic agonists (e.g. albuterol 90mcg per actuation for inhalation) when given via an inhaled route, may be beneficial to control respiratory signs of anaphylaxis
These medications cannot replace epinephrine as they have no effects on β1 or α1 receptors
Side effects: tachycardia, tremors 

A possible treatment plan for Lily may include the following:

  • Placement of an intravenous catheter
  • Administration of 10-20ml/kg of crystalloid as a bolus followed by reassessment of her perfusion parameters; additional boluses given as indicated.
  • Administration of epinephrine (adrenaline) 5mcg/kg IV bolus if she remains hypoperfused
  • Consideration for diphenhydramine 2m/kg IM and Dexamethasone 0.1mg/kg IV 

EpiPen:

Many carers will inquire about use of an EpiPen which people with hypersensitivities commonly carry. This is of most benefit for acute bronchospasm and upper airway edema. These are uncommon in canine cases of anaphylaxis so it may not be of much benefit to our patients.

The other major issue is dosing. The adult EpiPen contains 0.3mg of epinephrine (adrenaline) which would only be safe in animals weighing > 30 Kg); EpiPen Junior contains 0.15mg which could be used in animals between 15-30 Kg.

Finally, pet carers should be reminded that any animal treated with an EpiPen should still be seen by a veterinarian as soon as possible.

Feel free to contact me with comments or questions. Write them below or email me at lisamurphyirish@gmail.com. 

References: 

Shmuel, D.L. and Cortes, Y., 2013. Anaphylaxis in dogs and cats. Journal of Veterinary Emergency and Critical Care, 23(4), pp.377-394.

Walters, A.M., O'Brien, M.A., Selmic, L.E. and McMichael, M.A., 2017. Comparison of clinical findings between dogs with suspected anaphylaxis and dogs with confirmed sepsis. Journal of the American Veterinary Medical Association, 251(6), pp.681-688.

Aharon, M.A., Prittie, J.E. and Buriko, K., 2017. A review of associated controversies surrounding glucocorticoid use in veterinary emergency and critical care. Journal of Veterinary Emergency and Critical Care, 27(3), pp.267-277.

Mink, S.N., Simons, F.E.R., Simons, K.J., Becker, A.B. and Duke, K., 2004. Constant infusion of epinephrine, but not bolus treatment, improves haemodynamic recovery in anaphylactic shock in dogs. Clinical & Experimental Allergy, 34(11), pp.1776-1783.

Silverstein, D. and Hopper, K., 2014. Small Animal Critical Care Medicine. Elsevier Health Sciences.

Quantz, J.E., Miles, M.S., Reed, A.L. and White, G.A., 2009. Elevation of alanine transaminase and gallbladder wall abnormalities as biomarkers of anaphylaxis in canine hypersensitivity patients. Journal of veterinary emergency and critical care, 19(6), pp.536-544.