BackgroundEarly detection of minor strokes and their treatment that aim to prevent from complications into severe strokes is a process of secondary prevention. There is a need to extensively use image diagnostics (CT, MRI) because signs are obscure, at times without focal neurological sign but can have special mental or psychological syndromes. The start of minor stroke studies in Mongolia will enable further deepening of these studies in future and give an impetus to identification of theoreticaland practical aspects together with further improvement of diagnostics, treatment and prevention of minor strokes.GoalTo develop and introduce the diagnostic criteria of ischemic and hemorrhagic minor strokes in accordance to the concepts of minor strokes and to treat minor stokes in order to prevent complications into severe strokes.Materials and MethodCurrently there are no globally accepted diagnostic criteria for minor stroke. We support the 1981 WHO criteria of minor strokes as strokes neurological signs of which disappear in relatively short period of time. There is a general notion that it should mean all light forms of stroke other than severe strokes. In cases of neurological signs of a minor stroke, complete recovery and elimination of the symptoms take up to 3 weeks. Most scholars tend to consider ischemic lacunar strokes (arising from occlusion of arteriole vessels deep in the brain and with size of 0.5-20 mm) as minor strokes. We maintained the concept that characteristic features of these strokes are their limited focal areas and the following neurological symptoms: pure motor, pure sensory, light ataxia, etc. We also duly considered a suggestion (D. German, L. G. Koshchug et al, 2008 ) to define minor hemorrhagic strokes as strokes with diameter less than 2 cm and blood volume less than 5 cm3.We identified 60 patients with minor strokes, involved in monitoring using special research template (with a term of at least 1.5years) and involved in pathogenesis treatment. In the treatment, we maintained a principle of differential diagnosis of ischemic stroke symptoms. Specifically, we differentiated the following: signs related to an atherotromb, cardio-embolic, lacunar, hemodynamic, hemorheologic pathogenesis. To verify the diagnoses, we used MRT and CT image tests. We executed paraclinic tests in order to identify risk factors: Doppler-duplex-sonography, brain angiography, blood lipid fraction, ECG, EchoCG, heart Holter, blood hemorheology test, and identified the most affecting factors (hereditary factors, excess weight, smoking etc).Results: Our study identified the following clinical forms: lacunar stroke, non-lacunar minor stroke, and hemorrhagic minor stroke. Among the minor strokes, the lacunar stroke dominates (48%), the nonlacunar stroke is the next (27.7%), and the hemorrhagic was found to be the least common 25%. From among a host of risk factors, arterial hypertension is dominant (86%) either alone or in combination with such other diseases as diabetes, atherosclerosis etc. Diabetes occurrence was 5 cases (8,3%) which is fewer than in some foreign studies.The clinic of minor stroke also varies. The strength and expression of their symptoms compared with those of severe strokes are unique in the following:- Relatively lighter and recover faster as a result of treatment even in acute forms,- Some are without specific clinical signs (“silent stroke”).- Some minor strokes have micro focal signs, for example, “pure motor”, pure sensory, ataxia etc, in other words, the signs are limited.- In cases of lacunar strokes, predominantly deep brain arterioles are damaged.- Whereas in non-lacun strokes, embolic, ateroma, thrombotic mechanisms are predominant suchas distal branches of big artery. - In cases of hemorrhagic minor strokes, arteriopathy distortions occur not only in depth of brain but also in any small lobar vessels of brain.- Focal lesions have some variations by their pathological locations and minor stroke signs.In non-lacunar strokes (25%), the focal damages predominantly occur in branches of large intra/extra cranial arteries. In cases of lacunars strokes, the focal lesion is not in branches of large intracranial vessels, but is predominantly in basal ganglia, deep white matter, thalamus, pons and in area of deep penetrating arterial vessels. However, focal infarcts in cerebella may occur in any form of minor strokes.ConclusionAccording our study there were identified 3 subtypes of minor stroke. The finding is that lacunars and hemorrhagic minor strokes are more likely to give grounds to severe strokes. From this, it can be concluded that there are specific factors in the population of Mongolia to affect the genesis of minor strokes, namely, arterial hypertension which is directly related with these forms of minor strokes. We appropriate the WHO criteria of minor stroke that is neurological signs of a minor stroke, complete recovery and elimination of the symptoms take up to 3 weeks. In treatment of minor stroke, we suggest that minor strokes should be treating by pathogenetic therapy. Namely, antihypertensive therapy for lacunar infarction, anti-aggregation therapy for nonlacunar infarction and haemostatic and antihypertensive therapy for hemorrhagic minor stroke.