Abstract
Neurologic and visual symptoms frequently occurred in 56 reported patients with essential
thrombocythemia (ET). They may either precede or follow the well-known microcirculatory
complications of ET of acroparesthesias, erythromelalgia, and acrocyanosis or ischemia
of one or more toes. In comparison with transient ischemic attacks in patients with
vascular risk factors, the usual neurologic presentation of ET consists of brief attacks
of sudden cerebral or visual dysfunction, which can be either well localized or diffuse
and entirely nonspecific. A dull and throbby headache usually lasting for several
hours frequently accompanies the neurologic symptoms. Visual symptoms are less frequent
and include transient monocular blindness and global symptoms such as scintillating
scotomas and attacks of blurred vision. Neurologic and visual symptoms may leave minor
sequelae but are generally nondisabling. The striking similarity to migraine, together
with the absence of vascular risk factors and the striking efficacy of aspirin treatment
supports the hypothesis that the ischemic neurologic and visual symptoms in ET are
caused by shear rate-induced intravascular activation and aggregation of platelets
with subsequent transient sludging or occlusion of the cerebral arterial microvasculature.
Available data show that both the erythromelalgic distress and the ischemic neurologic
attacks in ET are completely abolished by control of platelet function with low dose
aspirin alone or reduction of platelet counts to normal as well as by the combination
of platelet reducing therapy and low-dose aspirin. Early recognition and appropriate
treatment of neurologic symptoms in patients with ET is therefore of great clinical
relevance.
Keywords:
Essential thrombocythemia - transient ischemic attacks - migraine accompaniments -
low-dose aspirin - platelets
