Sepsis in dogs and cats | Dr. Justine Lee, DACVECC, DABT, Board-certified Veterinary Specialist

Posted by justinelee in Animal Safety, Blog

What is sepsis? If your dog or cat was just diagnosed with sepsis, it’s a life-threatening infection that you must be aware of. Sepsis is one of the leading causes of death in human – and likely veterinary – intensive care units. The term sepsis is defined as an overwhelming infection is the body, typically where bacteria has spread to the blood stream. The body responds to sepsis by triggering its inflammatory system, where inflammatory mediators and cytokines are released.

Unfortunately, sepsis can result in inappropriate, severe inflammation, commonly called systemic inflammatory response syndrome (SIRS). Untreated, SIRS and severe sepsis can progress to organ failure (typically called multiorgan dysfunction syndrome or MODS). This can be seen as acute kidney failure (e.g., elevated kidney values such as creatinine and BUN), acute respiratory distress syndrome (ARDS) (e.g., acute difficulty breathing), liver failure (e.g., increased liver enzymes) and even gastrointestinal failure (e.g., bloody diarrhea, bloody vomiting, etc. Even with aggressive treatment, sepsis can progress to septic shock, and is often fatal in dogs and cats. Sepsis typically has a poor to grave prognosis, with overall survival being reported in veterinary medicine anywhere between 20% to 68% in dogs and cats.1-6

So what causes it? Sepsis is typically caused by an untreated, severe infection. This can be seen from numerous sources in the body. The most common source of sepsis is often related to the gastrointestinal tract (e.g., stomach, intestines). Other sources include:

• Ruptured intestines (e.g., typically from intestinal cancer or a foreign body obstruction)
• Ruptured organs (e.g., a ruptured stomach secondary to gastric dilatation volvulus; a ruptured bladder secondary to bladder stones; a ruptured gall bladder secondary to gall bladder stones)
• Severely infected wound (e.g., abscess, bite wound)
• Urinary tract infections (UTI) that migrated up to the kidney, resulting in a severe kidney infection (e.g., pyelonephritis)
• Pancreatic infection (e.g., pancreatitis, pancreatic abscess)
• Uterine infection in intact females (e.g., pyometra)
• Prostatic infection in intact male dogs (e.g., prostatic abscess)
• Severe pneumonia of the lungs

Rarer causes of sepsis include:
• Bacterial infection on the heart valves (e.g., bacterial endocarditis)
• Bacterial infection in the vertebrae (e.g., diskospondylitis)
• Blood infections
• Joint infections
• Severe dental disease

There are no specific breeds that are documented to be predisposed to sepsis. That said, clinically, certain breeds and ages of dogs and cats may be slightly more overrepresented. Clinically, it seems like Labradors and mixed breed dogs seem to develop sepsis more, as do older cats. This may be due to the popularity and nature of dogs; for example, the Labrador retriever has been bred to be so food-motivated (hence, easier to train) that they may present more for intestinal obstructions that had perforated due to something stuck in the intestines (e.g., foreign bodies like toys, rawhides, etc.). Older cats may develop sepsis secondary to ruptured cancer of the intestinal tract. Lastly, neonates (e.g., puppies and kittens) and immunosuppressed patients (e.g., those on chronic steroids or chemotherapy) may be more at risk, as they cannot fight of infection as well.

Clinical signs
Signs of sepsis range tremendously depending on when it is first detected. These include:

• Lethargy
• Malaise
• Depression
• Not moving or getting up
• Dehydration
• Drooling
• Decreased appetite to complete anorexia
• Vomiting
• An abnormal heart rate (e.g., elevated heart rate in dogs, slower heart rate in cats)
• An abnormal temperature (e.g., either hyperthermia/fever or hypothermia)
• Abnormal gum color (from dark red to pale pink)
• Breathing harder than usual
• Exercise intolerance
• Difficulty breathing
• Acting painful
• Groaning when getting up or moving
• Diarrhea
• Straining to urinate or defecate
• Jaundice (e.g., yellowing of the gums and skin)
• Collapse
• Abnormal thirst or urination (e.g., increased or decreased)
• Excessive licking of the rear end
• A foul odor from the rear end
• Vaginal discharge
• Warm or cold to the touch
• Fever
• A distended abdomen
• Seizures
• Bruising
• Death, even with treatment

Diagnosis
The diagnosis of sepsis is typically based on an extensive work-up, including blood work, x-rays, ultrasound, and even fluid analysis (off abnormal fluid in the abdomen, chest, etc.). Tests that your veterinarian may need to perform include:

• Complete blood count (looking at the white and red blood cells and platelets)
• Chemistry (looking at the kidney and liver function, protein, blood glucose/sugar, electrolytes)
• Urinalysis
• Urine culture
• Chest and abdominal x-rays
• Abdominal ultrasound
• Fluid analysis if there is abnormal fluid in the abdomen or chest
• Culture of the fluid
• Coagulation testing (including a PT, PTT, and platelet count)
• Blood cultures (rare)
• CT or MRI
• Ultrasound of the heart (e.g., echocardiogram)

With sepsis, there are certain blood work changes that are highly suggestive of severe infection, including:

• A very elevated or decreased white blood cell count
• A very elevated (e.g., hyperglycemia) or decreased blood sugar (e.g., hypoglycemia)
• An elevated or decreased red blood count (from dehydration or anemia)
• Increased liver enzymes (e.g., total bilirubin)
• Increased kidney values
• Abnormal clotting due to a severe complication called disseminated intravascular coagulation (DIC)

Treatment
Ultimately, the goal of treatment for sepsis is removing the source of infection (which is typically done by surgery, if involving the abdomen) and aggressive supportive care. While there is no “cure” for sepsis, supportive care includes:

• Intravenous (IV) fluids to help hydrate
• IV protein (called colloids such as Hetastarch to help increase the protein in the blood stream and blood pressure)
• Possible plasma transfusions if DIC is present
• Possible blood transfusions if anemia is present
• Vasopressors to increase the blood pressure
• Blood pressure, electrocardiogram (ECG), blood glucose monitoring
• Blood work monitoring (specifically of the electrolytes, blood sugar, white and red blood cell count, and clotting)
• Dextrose (e.g., sugar) supplementation
• IV antibiotics
• Anti-vomiting medication
• Pain medication
• Nutritional support
• Surgery, if indicated

Prevention
The best way to prevent sepsis is to always seek veterinary attention as soon as you notice any medical problems in your pet. The sooner you recognize a problem, the easier it will be to treat. For example, if your dog shows signs of a UTI (e.g., increased urination, bloody urine, straining to urinate, etc.), seek veterinary attention immediately before it progresses to the kidneys. As soon as your dog or cat shows signs of lethargy, anorexia, and vomiting, seek veterinary attention for x-rays to rule out an obstruction. Once the problem progresses, severe complications can be seen. If sepsis is seen, immediate advanced care at a tertiary referral or specialty hospital is recommended for life-saving care and monitoring.

Prognosis
Sepsis has a very poor to grave prognosis once it develops. Even with aggressive treatment and expensive therapy, dogs and cats can succumb.

References:
1. Boller EM, Otto CM. Septic Shock. In Small Animal Critical Care Medicine. Eds. Silverstein DC, Hopper K. Saunders-Elseiver 2009:pp. 459-463.
2. Costello MF, Drobatz KJ, Aronson LR, King LG. Underlying cause, pathophysiologic abnormalities, and response to treatment in cats with septic peritonitis: 51 cases (1990-2001). J Am Vet Med Assoc 2004;225(6):897-902.
3. Mueller MG, Ludwig LL, Barton LJ. Use of closed-suction drains to treat generalized peritonitis in dogs and cats: 40 cases (1997-1999). J Am Vet Med Assoc 2001;219(6):789-794.
4. Lanz OI, Ellison GW, Bellah JR, et al. Surgical treatment of septic peritonitis without abdominal drainage in 28 dogs. J Am Anim Hosp Assoc 2001;37:87-92.
5. Greenfield CL, Walshaw R. Open peritoneal drainage for treatment of contaminated peritoneal cavity and septic peritonitis in dogs and cats: 24 cases (1980-1986). J Am Vet Med Assoc 1987;191(1):100-105.
6. Bentley AM, Otto CM, Shofer FS. Comparison of dogs with septic peritonitis: 1988-1993 versus 1999-2003. J Vet Emerg Crit Care 2007;17(4):391-398.