A study of association between the national institute of health stroke scale score and arteriographic findings in acute ischaemic stroke
Keywords:NIHSS score, Acute ischaemic stroke
Background: In an ischaemic stroke, a strong correlation exists between the stroke severity and the level of arterial occlusion. Patients with major or proximal artery occlusion tend to have worst clinical picture and poor outcomes; and they are most benefited by revascularization interventions. These patients can be identified early before angiography by clinical scoring methods like National Institute of Health Stroke Scale (NIHSS) score. The NIHSS score (range 0-42) is a 15 item neurological examination stroke scale used to evaluate the effects of acute cerebral infarction on levels of consciousness, visual field loss, extra ocular movements, motor strength, ataxia, sensory loss, language, dysarthria and neglect.
Methods: A prospective study of 50 patients, who were admitted to the hospital with an acute ischaemic stroke within 12 hours of onset, was carried out to evaluate the relationship of NIHSS score and MR angiographic (MRA) findings.
Results: We found that majority of patients (38%) belonged to 6th decade with mean age of 59 years. Out of various risk factors, hypertension (64%) and smoking (48%) were most prevalent. Highest numbers of patients (40%) were in NIHSS score group 07 to 15. Out of 50 patients, 29 (58%) patients showed visible arterial occlusion on MRA. Median NIHSS score was 16 in occlusion group and 6 in non-occlusion group (p<0.01). In the same way, median NIHSS score in central occlusion group (20) was higher than distal occlusion group (11) (p<0.01). At NIHSS score 10, sensitivity and specificity to detect arterial occlusion in MRA was 86%. Positive predictive value (PPV) for arterial occlusion at >10 NIHSS score was 89% and PPV for detecting central occlusion at >12 NIHSS score was 87%.
Conclusions: In summary, a significant association was found between the NIHSS score and the presence and the location of a vessel occlusion in acute ischaemic stroke. In this era of reperfusion therapy where time is the most critical element, simple bedside score like NIHSS can greatly help in selecting patients requiring urgent treatment and improve patient disease outcome.
K Park. Park’s Textbook of Preventive and Social Medicine, 19th ed. Jabalpur: Bhanot Publishers. 2007:314.
McPhee SJ, Papadakis MA. General approach to disease prevention. In: Current Medical Diagnosis and Treatment, 47th ed. Columbus: The McGraw-Hill Companies, Inc. 2007:4.
NIH Stroke Scale. Available at: https://www.ninds.nih.gov/doctors/NIH_Stroke_Scale.pdf . Accessed on May 07, 2015.
Brott T, Adams HP, Olinger CP, Marler JR, Barsan WG, Biller J, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20:964-70.
The National Institute of Neurological Disorders and Stroke rtPA Stroke Study Group: Tissue plasminogen activator for acute ischaemic stroke. N Eng J Med. 1995;333:1581-7.