Hypovolemic shock is seen in all except
This most common form of shock results either from the loss of red blood cell mass and plasma from hemorrhage or from the loss of plasma volume alone due to extravascular fluid sequestration or GI, urinary, and insensible losses. The signs and symptoms of nonhemorrhagic hypovolemic shock are the same as those of hemorrhagic shock, although they may have a more insidious onset. The normal physiologic response to hypovolemia is to maintain perfusion of the brain and hea while attempting to restore an effective circulating blood volume. There is an increase in sympathetic activity, hyperventilation,collapse of venous capacitance vessels, release of stress hormones, and an attempt to replace the loss of intravascular volume through the recruitment of interstitial and intracellular fluid and by reduction of urine output. Mild hypovolemia (<=20% of the blood volume) generates mild tachycardia but relatively few external signs, especially in a supine young patient ( Table 270-5 ). With moderate hypovolemia (~20-40% of the blood volume), the patient becomes increasingly anxious and although normal blood pressure may be maintained in the supine position, there may be significant postural hypotension and tachycardia. If hypovolemia is severe (>=40% of the blood volume), the classic signs of shock appear; the blood pressure declines and becomes unstable even in the supine position, and the patient develops marked tachycardia, oliguria, and agitation or confusion. Perfusion of the central nervous system is well maintained until shock becomes severe. Hence, mental obtundation is an ominous clinical sign. ref:harrison&;s principles of internal medicine,ed 18,pg no 2219
Hemorrhage
Starvation
Vomiting
Diarrhoea
C.V.S