Because systemic inflammatory response syndrome (SIRS), sepsis, septic shock, and multiple organ dysfunction syndrome (MODS) represent a clinical continuum (see Overview), the specific features exhibited in any given case depend on where the patient falls on that continuum.
Fever is a common feature of sepsis. Fever of infectious origin results from resetting the hypothalamus so that heat production and heat loss are balanced to maintain a higher temperature. An abrupt onset of fever usually is associated with a large infectious load.
Chills are a secondary symptom associated with fever and result from increased muscular activity in an attempt to produce heat and thereby raise the body temperature to the level required to reset the hypothalamus.
Sweating occurs when the hypothalamus returns to its normal set point and senses that the body temperature is above the desired level. Perspiration is stimulated to offload excess body heat through evaporative cooling.
Altered mental function is often observed. Mild disorientation or confusion is especially common in elderly individuals. More severe manifestations include apprehension, anxiety, and agitation, and in some cases, coma may eventually ensue. The mechanism by which mental function is altered is not known, but altered amino acid metabolism has been proposed as a cause of metabolic encephalopathy.
Hyperventilation with respiratory alkalosis is a common feature of sepsis. Stimulation of the medullary ventilatory center by endotoxins and other inflammatory mediators has been proposed as the cause of...