Minor stroke, definition

Transient ischemic attack Definite Possible Minor stroke Definite Possible Note ... 

There is no accepted definition for what constitutes minor stroke. This distinction between minor and major stroke is sometimes based on an a score on the National... 

Over a five year period, 1438 patients were referred either to the hospital or to the study cUnic with a suspected TIA or minor stroke (defined on assessment as a score of < 3 on the National Institutes of Health Stroke Scale [NIHSS]) (Wityk et at 1994) (Fig. 10.1). Of these, a pre-scan diagnosis of definite or possible TIA was made in 405 patients (46% male, mean age 74 years), and definite or possible minor stroke in 414 patients (54% male, mean age 76 years). Overall, 97% underwent brain imaging for definite or possible events (699 CT, 93 MRI). 

Of 378 patients with a clinical diagnosis of definite minor stroke, there were nine (2.4% 95% Cl, 1.3-4.5) with non-vascular pathology (six intracranial tumors, one demyelination, one arachnoid cyst, one subdural hematoma). Possible minor stroke was diagnosed in 36, and non-vascular pathology was identified in five (13.9% 95% Cl, 6.1-28.7), all of whom had intracranial tumors. 

Table 10.3. Rates of infarction, primary hemorrhage or hemorrhagic infarction on CT scan among subjects with probable or definite transient ischemic attack or minor stroke in the Oxford Vascular Study (OXVASC)...

In the OXVASC cohort of patients with probable or definite TIA or minor stroke, 699 were imaged with CT. Rates of infarction and hemorrhage detected with CT are listed in Table 10.3. 

Among 334 patients with definite or possible minor stroke in OXVASC in whom hemorrhage could be detected reliably by either CT performed within 10 days or MRI (regardless of delay), primary hemorrhage was detected in 17 (5.1% 95% Cl, 3.2-8.0), and hemorrhagic transformation of an infarct in four (1.2% 95% Cl, 0.5-3.0). 

Recent research has shown that the risk of stroke immediately after TIA or minor stroke is considerable (Giles and Rothwell 2007 Wu et al. 2007). However, this poses a challenge to clinical services because although the majority of patients will, by definition, have suffered a transient illness with no immediate major sequelae, an important minority are at risk of a major stroke in the short term. Prognostic tools have, therefore, been developed to identify patients at high (and low) risk in order to inform public education, aid effective triage to secondary care and direct secondary preventive treatment. 

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