Muhammad University of Islam

Background: Aneurysmal subarachnoid hemorrhage (SAH) remains a leading cause of significant morbidity and mortality. Previous studies have shown that there is a systemic inflammatory response, characterized by leukocytosis or leukopenia in SAH. We investigated leukocyte subpopulation in serum and cerebral spinal fluid (CSF) at day 0 as a clinical predictor of delayed neurological deterioration defined as VS at any time during hospital stay. Methods: This is a retrospective study of non-traumatic SAH. Leukocyte subpopulations data in serum and CSF at day 0 were prospectively collected and compared with the development of clinical vasospasm (VS) vs no VS during the entirety of the patient’s hospital admission. Data was analyzed using univariate analysis. Clinical VS was defined as development of new focal neurological signs, deterioration in level of consciousness, or both, when the cause was felt to be ischemia attributable to VS after other possible causes of worsening (hydrocephalus, seizure, etc.). Results: A total of 47 subjects were screened and included in the analysis; 35 of these had no clinical VS and 12 had clinical VS. In those with and without VS, there was a significant difference in elevated leukocyte counts (16.9 vs. 12.5, p<.001) and neutrophils (13.3 vs. 10.4, p<.044). VS was not associated with monocytes (1.8 vs .48, p<0.30) or with lymphocytes (1.3 vs. 1.4, p<0.60). When adjusting for fever in a logistic regression model, this association held for leukocyte count (OR:1.32, p<0.012) and was borderline significant for neutrophils (OR:1.20, p<0.051). Conclusion: There was a statistically significant association between total serum leukocyte at day 0 and incidence of VS. Neutrophils may also identify potential neurological deterioration. Total serum leukocyte may be a valuable predictor of VS and neurological deterioration in general.

Non-negative definite Lyapunov functionals are employed to obtain sufficient conditions that guarantee exponential stability of the zero solution of a non-linear discrete system. The theory is illustrated with several examples.