Primary Thalamic Haemorrhage – Clinical Profile and Prognostic Predictors from a Series of 117 Cases

Abstract

Background: Studies on isolated primary thalamic hematomas are limited. This study analyses 117 patients with primary thalamic hematomas and attempts to identify the various prognostic factors influencing the outcome. Materials and Methods: A retrospective analysis of the case records was carried out to analyse the following prognostic parameters - GCS on admission, comorbidities like systemic hypertension and diabetes mellitus, side and site of hematoma, volume of the clot, presence of intraventricular haemorrhage (IVH), development of hydrocephalus, and the role of surgical intervention. A Chi-square test was used to compare categorical variables, and Student t-test and Mann Whitney test were applied to calculate the P-value for continuous variables for univariate statistics. Binary Logistic regression was used for multivariate analysis. Results and Discussion: This study group comprised 67 men and 50 women with a mean age of 62.05±11.71years. The mean GCS on admission in the study group was 11.56±3.28. The mean clot volume was 13±9.5ml and majority (89.74%) of the patients had clots with a volume of less than 20 ml. An intraventricular extension was noted in 98 patients. Craniotomy and surgical evacuation were performed in only two patients while external ventricular drainage with urokinase instillation was performed in 23 patients. Of the 117 patients, 3 had anterior thalamic clots, 19 had posterior thalamic clots, 13 had medial clots, 53 had lateral thalamic bleeds and 29 had global clots. The overall three-month mortality with thalamic bleeds was 28.2%. At the end of three months, 59 patients (50.42%) had a favourable outcome (mRS < 4). On univariate analysis, male sex, dominant side bleed, preoperative GCS of less than 8 (p < 0.001), presence of hydrocephalus (p< 0.004) and a need for EVD (p<0.012) were found to be significantly associated with mortality and poor outcome. Similarly, clot volume less than 20 ml, right-sided bleed and surgical evacuation were associated with a favourable outcome (p < 0.001). On multiple logistic regression, age, volume of hematoma and GCS on admission were predictors for mortality and volume of hematoma was a significant predictor of poor outcome. Conclusion: Thalamic hematomas include a spectrum of clots of varying dimensions at different locations and the outcomes need not be uniformly poor. Isolated thalamic hemorrhages are generally small in volume preferentially located in the lateral thalamus. Patients with right-sided bleeds and small clot volume perform well. Male sex, poor GCS on admission, clot volume above 20 ml, intraventricular extension and a need for external ventricular drainage adversely influence the outcome.