How is pseudosepsis differentiated from bacterial sepsis?

Updated: Feb 05, 2019
  • Author: Amber Mahmood Bokhari, MBBS; Chief Editor: Michael Stuart Bronze, MD  more...
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A common medicolegal error is failure to consider pseudosepsis as a cause of the presenting syndrome. Most causes of pseudosepsis are readily treatable if recognized and managed early.

Thus, before embarking on a workup for sepsis or beginning empiric antibiotic therapy, it is vital to rule out the treatable causes of pseudosepsis early in the disease process. Consider other causes or conditions that mimic the clinical and hemodynamic parameters of sepsis and differentiate between the distributive presentation versus septic shock (see Table 3 below). The causes of pseudosepsis must be identified because they require supportive, rather than antimicrobial, therapy.

Table 3. Noninfectious Conditions Mimicking Clinical and Hemodynamic Parameters of Sepsis (Open Table in a new window)

Clinical Presentations Mimicking Sepsis

Hemodynamic Parameters Mimicking Sepsis

Myocardial infarction

Spinal cord injury


Adrenal insufficiency

Diabetic ketoacidosis

Acute pancreatitis

Systemic lupus erythematosus flare with abdominal crisis


Ventricular pseudoaneurysm

Pulmonary embolism

Massive aspiration/atelectasis


Systemic vasculitis


Hypovolemia (eg, due to diuretics, dehydration)


Pseudosepsis is a common cause of misdiagnosis in hospitalized patients, particularly in the emergency department (ED) and ICU. The most common causes of pseudosepsis include gastrointestinal (GI) hemorrhage, pulmonary embolism, acute myocardial infarction (MI), acute pancreatitis (edematous or hemorrhagic), diuretic-induced hypovolemia, and relative adrenal insufficiency.

Patients with pseudosepsis may have fever, chills, leukocytosis, and a left shift, with or without hypotension. Many causes of pseudosepsis produce pulmonary artery catheter readings that are compatible with sepsis (ie, increased cardiac output and decreased peripheral resistance), which could misdirect the unwary clinician (see Table 4 below).

Table 4. Characteristics of Pseudosepsis and Sepsis (Open Table in a new window)





No definite source PLUS ≥1 abnormalities

Negative blood cultures excluding contaminants

Proper identification/process/source PLUS ≥1 microbiologic abnormalities

Positive buffy coat smear result OR several positive blood culture results with a pathogenic organism



⇑ CO


⇑ CO

Left ventricular dilatation


⇑ WBC count (with left shift)

Normal platelet count


⇑ Lactate

⇑ D-dimers


⇓ Albumin

⇓ Fibrinogen

⇓ Globulins

⇑ WBC count (with left shift)

⇓ Platelets


⇑ Lactate

⇑ D-dimers


⇓ Albumin


≤102°F ±

Tachycardia ±

Respiratory alkalosis ±


≥102°F OR

Hypothermia ±

Mental status changes ±


CO = cardiac output; FSP = fibrin split products; GI = gastrointestinal; GU = genitourinary; PT/PTT = prothrombin time/partial thromboplastin time; PVR = peripheral vascular resistance; WBC = white blood cell.

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