Diagnostic Accuracy of Computed Tomography Scan to Diagnose Subarachnoid Hemorrhage in Patients Presenting with Thunderclap Headache

Introduction: Thunderclap headache (TCH) is a severe headache that peaks within 60 seconds of onset. It’s an uncommon type of headache, but recognition and diagnosis are important because of the possibility of a serious underlying brain disorder. Severe headache has long been recognized as a signature feature of subarachnoid hemorrhage (SAH). Lumbar puncture (LP) has the advantage of picking up cases missed on computed tomography (CT) scan, owing to its ability to detect small bleeds directly from the cerebrospinal fluid (CSF). This study can help us in understanding the role of this modality for early diagnosis and therefore timely management of patients. Subject and methods:A retrospective cross-sectional study for a period of six months was conducted at a tertiary care hospital in Karachi, Pakistan. A total of 189 patients presenting with TCH were included in this study. CT was performed on Toshiba Activion 16 slice CT scanner (Toshiba Medical Systems, Otawara, Japan). Presence of SAH was confirmed by CSF analysis after LP. Data were registered on proforma, then transferred to IBM SPSS Statistics for Windows, Version 20.0 (IBM Corp., Armonk, NY) for statistical analysis. Diagnostic accuracy of CT scan in detecting SAH was calculated. Stratification was done on age and sex to see the effect of these modifiers on outcome using chi square test; p≤0.05 was considered as significant. Results:The average age of the patients was 47.97±9.96 years. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT was 88%, 91.4%, 78.6%, and 95.5%, respectively while diagnostic accuracy of CT scan in the detection of SAH was 90.48%.Conclusion:This study concludes that CT is the preferred non-invasive approach for the majority of patients who present with suspected SAH