Sepsis: Immune Response MeltdownPage 8 of 14

6. Diagnosis of Septic Shock

A patient who might be in septic shock needs a rapid assessment to exclude other major classes of shock such as cardiogenic (from myocardial infarction or ventricular arrhythmias), hypovolemic (from hemorrhage or dehydration), or anaphylactic.


Shock presents with hypotension, oliguria, abnormal mental status (restlessness, confusion, lethargy, or coma), and metabolic acidosis due to an increased concentration of lactate in the blood. When the shock is septic, it can also present with tachycardia, tachypnea, fever, and a high white blood cell count (Gaieski, 2013). A key sign in sepsis is hypotension that cannot be reversed with fluids alone.

The hypotension of shock may be absolute, with a systolic blood pressure <90 mm Hg. Alternately, the hypotension of shock may be relative and take the form of a drop in systolic blood pressure >40 mm Hg; in this situation, hypertensive people can be in shock although their presenting blood pressures are within the normal range. When a person is in shock, vasopressors are frequently needed to maintain adequate perfusion of tissues.

For a patient in shock, diagnostic tests, a physical examination, and a medical history should not delay procedures that will stabilize the patient’s circulation and respiration. Instead, data should be collected while the patient is being resuscitated. It is important to know the patient’s blood and serum chemistry values, so resuscitators need to draw blood samples.

Initial tests include a complete blood count with a differential, basic blood chemistries, liver function tests, coagulation studies, cardiac enzymes, blood gases, lactate levels, blood type with cross match, and toxicology screening (Shapiro et al., 2010). Two sets of blood cultures should be drawn with the initial labs and prior to administration of antibiotics.

Test Your Knowledge

Septic shock:

  1. Is caused by cardiac dysfunction such as heart failure or myocardial infarction.
  2. Presents with hypotension that cannot be reversed by fluid resuscitation alone.
  3. Typically presents with low blood lactate levels, low blood concentrations of CO2, and polyuria.
  4. Is treated only after immediate laboratory testing to determine the causative organism.

Answer: B

Toxic Shock Syndrome

Toxic shock syndrome is a rapid-onset form of septic shock that presents with fever, hypotension, rash, vomiting, and diarrhea. It was first associated with infections of high-absorbency menstrual tampons. Now it is recognized as originating from a variety of sources including sino-nasal surgical packing, peritoneal dialysis catheters, intravenous drug injections, and burn wounds. Fatality rates of 15% have been reported. Toxic shock syndrome is usually caused by Staphylococcus aureus. A related condition, toxic shock-like syndrome, is usually caused by Streptococcus pyogenes.

Toxic shock syndrome is triggered by bacterial toxins rather than by an overwhelming invasion of bacteria, and blood cultures are strangely negative. Staphylococci produce exotoxins, compounds that trigger inflammation directly. The exotoxins circulate in the bloodstream and set off inflammation throughout the body, activating and damaging the vascular endothelium of many tissues. As with all sepsis, when toxic shock syndrome leads to organ failure, the chance of mortality is high.

Source: Schwartz, 2011.

Test Your Knowledge

Toxic shock syndrome is:

  1. Severe staphylococcal bacteremia but without shock.
  2. Staphylococcal bacteremia typically diagnosed by positive blood cultures.
  3. A form of septic shock triggered by bacterial toxins.
  4. A rapid-onset sepsis causing severe lung injury, pulmonary edema, and hypoxemia and requiring mechanical ventilation.

Test Your Knowledge

Q: What are the current recommendations for patient education in the use of tampons?

A: Change the tampon every 2-4 hours and don’t leave tampons in over night.

Answer: C

Differential Diagnosis

For septic shock, the differential diagnosis should consider a different list of primary conditions than for sepsis without shock. The accompanying box lists the range of serious problems to consider when a septic shock-like condition is being diagnosed.

Differential Diagnosis for Septic Shock

  • Acute blood loss
  • Adrenal insufficiency
  • Anaphylaxis and anaphylactoid reactions
  • Cardiac arrest followed by post resuscitation syndrome
  • Cardiogenic shock
  • Hypovolemic shock
  • Myocardial infarction
  • Myxedema coma
  • Neurogenic shock after an injury
  • Paralysis
  • Pericardial tamponade
  • Post cardiopulmonary bypass syndrome
  • Pulmonary embolus
  • Severe dehydration
  • Tension pneumothorax
  • Thyroid storm
  • Transfusion reactions
  • Vasogenic shock

Source: Gaieski, 2013.