Increases in platelets above the normal level may occur due to '''physiological''' or '''pathological''' processes.
+
Increased platelet number above normal levels may occur due to physiological or pathological processes.
−
*Physiological
+
−
**'''Splenic contraction''' pushes sequestered platelets into the circulation. This phenomenon is especially marked in horses which have a muscular splenic capsule.
+
Physiological causes include:
−
**'''Splenectomy''' prevents the sequestration of platelets in the spleen, resulting in constantly increased levels of platelets.
+
*'''Splenic contraction''' which pushes sequestered platelets into the circulation. This phenomenon is especially marked in '''horses''' which have a muscular splenic capsule.
−
**As part of a response to '''[[Anaemia - Introduction|anaemia]]''', a '''reactive thrombocytosis''' is often documented and this may precede signs of regeneration.
+
*'''Splenectomy''' prevents the sequestration of platelets in the spleen, resulting in consistently increased levels of platelets.
−
*Pathological
+
*As part of a response to [[Anaemia - Introduction|anaemia]] a '''reactive thrombocytosis''' is often documented and this may precede signs of regeneration.
−
**'''Essential thrombocythaemia''' is a rare myeloproliferative disease that results in the excessive production of platelets which function abnormally. Affected animals suffer from bouts of spontaneous haemorrhage.
+
+
Pathological
+
*'''Essential thrombocythaemia''' is a rare myeloproliferative disease that results in the excessive production of platelets which function abnormally. Affected animals suffer from bouts of spontaneous haemorrhage.