Besides, nearly all kinds of distributive shock such as septic shock, neurogenic shock, anaphylactic shock, drug and toxin-induced shock, endocrine shock can turn out into refractory vasodilatory shock when the original shock becomes more severe.The most common cause of vasodilatory shock is sepsis. Except sepsis, other causes comprise severe acute pancreatitis, post cardiopulmonary bypass vasoplegia and other triggers for a systemic inflammatory response syndrome. Low serum calcium values might take a role in vasodilatory shock. Pathophysiology
In the cases of cardiogenic shock resulting from heart failure or acute hemorrhagic shock caused by a large volume of blood loss, the body constricts peripheral vessels to reverse the low arterial pressure that causes inadequate tissue perfusion. With vasodilatory shock, it is difficult for the peripheral vascular smooth muscle to constrict. In refractory vasodilatory shock, peripheral vascular smooth muscle responds poorly to therapy with vasopressor drugs.Vasopressin deficiency may play an important role in vasodilatory shock. In refractory vasodilatory shock, the patient has both vasopressin secretion deficit and an advanced resistance to vasopressin-induced blood-pressure changes. Some have hypothesized that patients with vasopressin deficiency, including a decrease in baroreceptor stimulation, appear to have impaired autonomic reflexes. Tone may be inhibited by atrial stretch receptors and vasopressin release may be inhibited by nitric oxide or high circulating levels of norepinephrine.Vasodilatory shock is often involved with the dysfunction of physiologic compensatory mechanisms such as the sympathetic nervous system, vasopressin arginine system and renin-angiotensin aldosterone system. Diagnosis
The definition of refractory shock or vasodilatory shock varies.
He was unaware that, in 1916, Freund had correctly observed that these pigmentation effects were due to sun exposure after the use of Eau de Cologne, a perfume infused with bergamot oil. It is now known that bergamot oil contains a significant amount of bergapten, a linear furanocoumarin that gets its name from the bergamot orange. In 1937, dermatitis from Heracleum mantegazzianum was reported by Miescher and Burckhardt who suspected the possibility of light sensitization. A few years later, Kuske confirmed this hypothesis. In 1942, Klaber introduced the term "phytophotodermatitis" to emphasize that both plants and light were required to affect a reaction.Darrell Wilkinson, a British dermatologist, gave an accurate description of the disease in the 1950s. In 1961, Efremov reported 357 cases of phytophotodermatitis from Heracleum dulce (sweet cow parsnip). He "noted the requirement for sunlight in evoking the dermatitis since inunction of the juice of the plant without exposure to sunlight was harmless." Between 1962 and 1976, numerous reports of phytophotodermatitis from giant hogweed (Heracleum mantegazzianum) were reported. By 1980, the photosensitizing effects of various plant species had become well known (as evidenced by the comprehensive work of Mitchell and Rook). See also
List of cutaneous conditions
Photodermatitis
Psoralen
Photosensitivity in humans
Stinging plant, plants with fragile silica hairs that inject venoms

References
External links
 Media related to Phytophotodermatitis at Wikimedia Commons