Mean platelet volume is increased in hyperthyroidism

Abstract

In 28 unselected patients with hyperthyroidism, platelet count, platelet hematocrit, mean platelet volume, and platelet distribution width were measured at the time of presentation and again when the patients were euthyroid. On return to the euthyroid state, there were highly significant falls in the mean values of the mean platelet volume (16% decline, P less than 0.001) and the platelet hematocrit (16% decline, P less than 0.001) and a slight but highly significant increase in the mean value of the platelet distribution width (2% increase, P less than 0.01). A decline in mean platelet volume was observed in 24 of 28 patients (86%); three patients showed no change. There was no significant change in the mean value of the platelet count. The observed effects of thyrotoxicosis on platelets appeared to be largely independent of the well-known effects on erythrocytes and white blood cells. An increase in mean platelet volume is a regular feature of hyperthyroidism that has not previously been described.

Thyroxine Suppresses Thrombocytopoiesis and Stimulates Erythropoiesis in Mice

“…2) is presumed to be a compensatory effort to maintain platelet mass in the face of marked thrombocytopenia. This finding is in agreement with reports of increased platelet volume in human hyperthyroid patients (22,25).…”

“…This is in contrast to canine and human patients, in whom neoplastic (thyroid adenocarcinoma in canines) or autoimmune (Graves' disease in humans) diseases are often the cause of increased thyroid hormone levels; these diseases can have broader systemic effects and could be confounding factors in such an analysis. Furthermore, the reason for the difference in platelet size in hyperthyroid patients should be evaluated more fully to characterize changes in thrombocytopoiesis that occur in this condition (24)(25)(26).…”

“…Use of platelet volume or size to characterize blood disorders allows detection of more subtle changes in thrombocytopoiesis (24) than platelet count alone. Ford et ale (25) have described an increased mean platelet volume in human hyperthryoid patients, and conversely, van Doormal et ale (26) have reported that small-sized platelets predominate in the hypothyroid state.…”

Mean platelet volume is significantly associated with serum levels of thyroid-stimulating hormone in a cohort of older euthyroid subjects

“…The first ever study was published by Ford et al (16). The platelet count and the MPV were assessed in 28 unselected patients with hyperthyroidism at the time of presentation and again when the patients were euthyroid.…”

Mean Platelet Volume may be Reflects the Disease Activity of Ulcerative Colitis

“…For example, MPV and platelet distribution width bear importance in the discrimination of myeloproliferative diseases, essential thrombocytosis and reactive thrombocytoses (6,7). Many studies on clinical benefit of MPV were made on many subjects such as splenectomy, microcytic anemia, serebral infarct (8-10), thrombocytopenia (11,12), thrombocytoses (6,7), congenital platelet diseases, sepsis, chronic obstructive lungal diseases (13), chronic venous failure (14), high MPV in hyperthyroidism (15), low MPV in hyperthyroidism (16), hypertension and preeclampsia in pregnanacy, organic solvent toxicity.…”