Sepsis and SIRS (Canine) — NAVLE Prep

Quick anchor

Trigger

Infection + shock + inappropriate temperature

First step

Perfusion and oxygen delivery first

Treat

Fluids + antibiotics + source control

Trap

Do not delay antibiotics after sampling

Exam core — read this first

Suspect sepsis → when SIRS signs occur with an infectious source

Stabilize first → restore perfusion and oxygen delivery before getting lost in details

Antibiotics → start promptly after appropriate cultures if feasible

Definitive plan → control the septic source, not just the blood pressure

Pattern recognition

Core pattern

Suspected infectionTachycardia / poor perfusionAbnormal temperature

Supporting clues

Injected mucous membranesBounding or weak pulsesHyperlactatemiaHypotensionAltered mentation

NAVLE trigger: SIRS alone is not the endpoint. Boards want you to ask whether an infectious source makes this sepsis.

Decision core — what NAVLE actually asks

Poorly perfused septic patient

→ Start aggressive stabilization, oxygen support as needed, and obtain rapid minimum database data

Strong suspicion of sepsis

→ Sample first if you can do it fast, then begin broad-spectrum antimicrobials promptly

Persistent instability

→ Reassess source control, perfusion endpoints, and whether vasopressor support is needed

Key interpretation

Lactate

↑ May rise

Tracks poor perfusion

CBC

Inflammatory change

Neutrophil changes may support sepsis

Blood pressure

↓ Low

Shock physiology

Glucose

May drop

Hypoglycemia can occur in severe sepsis

Temperature

High or low

Hypothermia can be severe sepsis, not reassuring

Source

Must identify

Abdomen, lungs, uterus, wounds, urinary tract

⚠ A normal or low temperature in a very sick dog does not rule out sepsis. Hypothermia can be an ominous finding.

Treatment

Step 1

IV crystalloids, oxygen support as indicated

Resuscitation comes before diagnostic perfection.

Step 2

Broad-spectrum antimicrobials after cultures if feasible

Do not lose time once sepsis is strongly suspected.

Step 3

Source control: surgery, drainage, debridement, uterine removal, etc.

Antibiotics alone do not solve a contained septic source.

NAVLE traps — where students lose marks

Do not confuse SIRS with confirmed sepsis

You still need an infectious source or strong suspicion of one.

Do not delay antibiotics too long while chasing cultures

Sample quickly if possible, then treat.

Normal blood pressure early does not prove the patient is safe

Perfusion can still be poor while shock evolves.

Source control is treatment, not an optional add-on

Septic abdomen or pyometra questions usually hinge on this.

Differentials — how to separate these on NAVLE

Fast separator: Sepsis is shock physiology with an infectious driver. Compare it with sterile SIRS, hemorrhage, and anaphylaxis.

Disease	Trigger	Perfusion	Key separator
Sepsis	Infectious source	Shocky	Needs antibiotics + source control
Sterile SIRS	Inflammation without infection	Can be shocky	No septic source identified
Hemorrhagic shock	Blood loss	Shocky	No infectious trigger
Anaphylaxis	Allergic trigger	Can be shocky	Acute exposure pattern
GDV	Obstructive shock	Shocky	Retching + distended abdomen

30-second revision

Think sepsis whenSIRS signs + infectious source

First priorityPerfusion / oxygen delivery

ThenRapid sampling + antibiotics

Do not forgetSource control

Perfusion clueLactate may be high

Temperature trapHypothermia can still be sepsis

Critical trapSIRS alone ≠ proven sepsis

Practice questions

Pre-built NAVLE-style · Sepsis and SIRS

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Q1Recognition

A dog is tachycardic, weak, hypotensive, and hypothermic with a ruptured pyometra. Which diagnosis best fits the overall problem?

Q2Next best step

In a dog with suspected sepsis, blood cultures can be obtained immediately. Which sequence is most appropriate?

Q3Source control

Which statement about definitive management of septic peritonitis is most accurate?

Q4Trap question

Which finding does NOT rule out canine sepsis?

Q5Differential

What most strongly separates sepsis from sterile SIRS on NAVLE?