Treatment of canine sepsis: First identify, eradicate the cause - DVM
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Treatment of canine sepsis: First identify, eradicate the cause


DVM360 MAGAZINE


Treatment

The most important aspect of treating sepsis in dogs centers on the identification and eradication of the inciting cause (see "Products for management of canine parvoviral enteritis or bacterial infection" below).

An effort should be made to identify the causative microorganism through cytologic examination and culture. Although stringent effort should be made to identify the cause of sepsis, antimicrobial treatment should not be withheld pending these results.

The use of appropriate broad-spectrum antimicrobial agents is recommended. Since bacteria are the leading cause of sepsis in dogs, typically broad-spectrum antibiotic therapy (e.g., fluoroquinolone plus penicillin derivative) is instituted. The remainder of medical therapy centers on maintenance of tissue perfusion and aggressive supportive care. Treatment should, however, be tailored to the needs of the individual dog.

Cardiovascular support is an important aspect of maintaining good tissue perfusion. Intravenous fluid therapy should be instituted in any dog suspected of having sepsis. For some dogs, the administration of colloids and vasopressors will be indicated. Dogs should be volume-resuscitated prior to the institution of vasopressor therapy because vasopressors may alter microvascular circulation, leading to increased tissue hypoxia.

In one experimental study of canine sepsis, epinephrine was found to adversely affect organ function, systemic perfusion and survival as compared to the use of norepinephrine or vasopressin. Along with maintaining good tissue perfusion, maximizing cellular oxygenation is an important aspect of the treatment of sepsis. This may be accomplished by ensuring good oxygen-carrying capacity, providing supplemental oxygen when indicated and preventing microthrombi formation.

Additional supportive care, including nutritional management, frequent reassessment and good nursing care are key aspects in the management of sepsis. Because bacterial translocation from the GI tract is a substantial concern, the early introduction of preferably enteral or, in dogs with vomiting, parenteral nutrition is paramount. Often these dogs require a feeding tube, and this measure should be taken as soon as possible in a hyporexic or anorexic dog.

Additionally, medication aimed at maintaining normal GI-protective mechanisms (e.g., omeprazole, famotidine, Carafate) should be considered. Careful monitoring for any change in the dog's status (e.g., hypotension, dehydration, organ dysfunction, serum chemistry profile or coagulation abnormalities) is prudent and appropriate therapy should be administered as indicated.

Finally, care should be taken to ensure adequate nursing care, including careful use of aseptic technique during catheter manipulation and frequent turning/movement of the afflicted dog.

Novel therapies

Polymyxin B is a cyclic cationic polypeptide antibiotic that binds the endotoxin that is released from gram-negative bacteria during sepsis, causing activation of inflammatory cells. Endotoxin that is bound to polymyxin is unable to activate inflammatory cells, preventing cytokine production and development of systemic inflammation.

Administration of polymyxin may be an efficacious, affordable and safe means of inhibiting gram-negative, bacteria-induced inflammation dogs. In a placebo-controlled clinical trial, dogs treated with polymyxin (12,500 IU/kg, IM BID) had significantly improved hydration, capillary refill time, pulse quality and significantly lower plasma TNF concentrations than the control group during naturally occurring gram-negative sepsis.

Potential dose-dependent side effects of polymyxin B include respiratory depression, nephrotoxicosis, cardiovascular compromise and neuro-toxicosis. However, the dose needed to achieve anti-endotoxic effects is low, making these side effects unlikely. Polymyxin B is routinely used in the treatment of gram-negative sepsis in horses with good success. Therefore, polymyxin B may be considered as a potential treatment for gram-negative sepsis in dogs.

Activated protein C is an anticoagulant protein. It possesses anti-inflammatory, profibrinolytic and anti-apoptotic effects. During sepsis, there is a clear interrelation between the coagulation system and the inflammatory system. In a multi-center, randomized, controlled, clinical trial, recombinant human-activated protein C decreased mortality from severe sepsis in humans. A canine form of activated protein C is not available but, if developed, could be a promising novel treatment for sepsis in dogs.

Corticosteroids: The use of cortico-steroids for treating sepsis has fallen out of favor due to their immunosuppressive, ulcerogenic and prothrombotic nature. Additionally, clinical trials of the use of corticosteroids in human sepsis have been disappointing. One exception may be the use of low or physiologic doses of corticosteroids for management of relative adrenal insufficiency during sepsis.


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