Can Computed Tomography Angiography of the Brain Replace Lumbar Puncture in the Evaluation of Acute‐onset Headache After a Negative Noncontrast Cranial Computed Tomography Scan?

Objectives: The primary goal of evaluation for acute‐onset headache is to exclude aneurysmal subarachnoid hemorrhage (SAH). Noncontrast cranial computed tomography (CT), followed by lumbar puncture (LP) if the CT is negative, is the current standard of care. Computed tomography angiography (CTA) of the brain has become more available and more sensitive for the detection of cerebral aneurysms. This study addresses the role of CT/CTA versus CT/LP in the diagnostic workup of acute‐onset headache. Methods: This article reviews the recent literature for the prevalence of SAH in emergency department (ED) headache patients, the sensitivity of CT for diagnosing acute SAH, and the sensitivity and specificity of CTA for cerebral aneurysms. An equivalence study comparing CT/LP and CT/CTA would require 3,000 + subjects. As an alternative, the authors constructed a mathematical probability model to determine the posttest probability of excluding aneurysmal or arterial venous malformation (AVM) SAH with a CT/CTA strategy. Results: SAH prevalence in ED headache patients was conservatively estimated at 15%. Representative studies reported CT sensitivity for SAH to be 91% (95% confidence interval [CI] = 82% to 97%) and sensitivity of CTA for aneurysm to be 97.9% (95% CI = 88.9% to 99.9%). Based on these data, the posttest probability of excluding aneurysmal SAH after a negative CT/CTA was 99.43% (95% CI = 98.86% to 99.81%). Conclusions: CT followed by CTA can exclude SAH with a greater than 99% posttest probability. In ED patients complaining of acute‐onset headache without significant SAH risk factors, CT/CTA may offer a less invasive and more specific diagnostic paradigm. If one chooses to offer LP after CT/CTA, informed consent for LP should put the pretest risk of a missed aneurysmal SAH at less than 1%. ACADEMIC EMERGENCY MEDICINE 2010; 17:444–451 © 2010 by the Society for Academic Emergency Medicine     

Recurrent perimesencephalic nonaneurysmal subarachnoid hemorrhage within a short period of time: A case report

BACKGROUNDSpontaneous subarachnoid hemorrhage (SAH) is primarily caused by a ruptured intracranial aneurysm. Perimesencephalic nonaneurysmal SAH (PNSAH) accounts for approximately 5% of all spontaneous SAH. PNSAH displays favorable prognosis. The risk of hemorrhage recurrence is low. We report a case of PNSAH recurrence, occurring within a short time after the initial episode in a patient not receiving antithrombotic or antiplatelet drugs. CASE SUMMARYA 66-year-old male, without any history of recent trauma or antithrombotic/ antiplatelet medication, suffered two similar episodes of sudden onset of severe headache, nausea, and vomiting. A plain head computed tomography (CT) scan showed subarachnoid blood confined to the anterior part of the brainstem. Platelet count and coagulation function were normal. PNSAH was diagnosed by repeated head CT, magnetic resonance imaging, and cerebral angiography, none of which revealed the source of SAH. The patient was discharged without focal neurological deficits. At 6-mo follow-up, the patient had experienced no sudden onset of severe headache and presented favorable clinical outcome. Studies have reported a few patients with recurrent PNSAH, originating frequently from venous hemorrhage and conventionally associated with venous abnormalities. PNSAH recurs within a short time following the initial onset of symptoms, although the possibility of re-hemorrhage is extremely rare.CONCLUSIONPNSAH recurrence should arouse vigilance; however, the definite source of idiopathic SAH in this case report deserves further attention.     

动脉瘤性蛛网膜下腔出血后头痛病因学分析

目的分析动脉瘤性蛛网膜下腔出血(SAH)后头痛的病因。方法对107例发病后24h内CT诊断为SAH,并经全脑动脉造影(DSA)明确存在颅内动脉瘤的患者,分别在出血后1、2、3、5、7、10、14d行头痛数字评分(NRS),对中、重度头痛患者行头颅CT和经颅三维多普勒(TCD)检查,分析头痛发生原因,观察不同类型头痛的临床特点。结果86.9%(93/107)的动脉瘤性SAH患者病程中存在中、重度头痛,其中9.7%(9/93)源自动脉瘤再出血,其临床特点是突然出现剧烈头痛或原有头痛骤然加重,常伴有意识障碍或其他神经系统阳性体征;16.1%(15/93)的头痛患者CT显示继发性脑积水,且头痛多持续性加重,但有时可突然自行缓解;TCD检查显示12.9%(12/93)的头痛患者存在颅内血管痉挛,并可因病情持续加重出现局灶性神经功能缺损及意识障碍,61.3%(57/93)的患者无阳性发现,但临床表现类似。结论大多数动脉瘤性SAH患者存在中、重度头痛。     

蛛网膜下腔出血剧烈头痛相关因素分析

目的　了解蛛网膜下腔出血 (SAH)后剧烈头痛的相关因素 ,探讨SAH性头痛发病机制 ,为头痛的治疗提供理论依据和途径。方法　制定头痛程度量表 ,根据CT分析SAH在颅内的分布情况以及脑压、脑脊液 (CSF)改变与头痛程度的关系。结果　CT显示阴性或阳性结果均出现剧烈头痛 ;SAH头痛程度与CSF发生血性质变有关 ,而与血性程度和出血部位无关 ;脑压在 30 0mmH2 O以下时 ,头痛加重不明显 ;当脑压升高超过 30 0mmH2 O时 ,头痛明显加重 (P <0 0 0 5 ) ;用地塞米松鞘内注射能显著改善头痛。结论　发生质变的血性CSF引起蛛网膜下腔广泛的炎性反应是导致头痛的重要原因 ,高颅压是SAH头痛的次要因素 ,出血量导致高颅压引起头痛 ,可能与头痛持续时间有关。     

Subarachnoid hemorrhage diagnosis by computed tomography and lumbar puncture: Are fifth generation CT scanners better at identifying subarachnoid hemorrhage?

This study sought to determine the sensitivity and specificity of modern computed tomography (CT) scans for the diagnosis of subarachnoid hemorrhage (SAH). No studies have been done recently with fifth generation CT scanners to look at the diagnosis of SAH. A retrospective chart review was done of Emergency Department (ED), laboratory, and hospital records at Pitt County Memorial Hospital in Greenville, North Carolina over 1 year from January 1, 2002 to December 31, 2002. Patients presented with headache and had a CT scan of the head with a fifth generation multi-detector CT scanner followed by a lumbar puncture (LP) to rule out SAH. There were 177 patients who presented to the ED with headache and went on to have a CT scan and an LP to rule out SAH. No patients who had a negative CT were found to have a subarachoid hemorrhage. It is concluded that fifth generation CT scanners are probably more sensitive than earlier scanners at detecting SAH.     

蛛网膜下腔出血剧烈头痛的CT分析

目的　了解SAH后剧烈头痛与CT所示的关系 ,探讨SAH头痛的发病机理。方法　制定头痛程度量表 ,根据CT分析SAH的分布情况 ,结合CSF改变 ,判定出血量和出血部位与头痛程度的关系。结果　CT显示阴性或阳性结果均出现剧烈头痛 ,中等程度以上的出血较少量出血头痛程度明显加重。A区和B区出血头痛程度相同。CSF血性改变程度与头痛严重程度无明显相关。结论　CSF发生血性质变是导致头痛的重要原因 ,头痛程度与出血部位无关。     

Sensitivity of New-generation Computed Tomography in Subarachnoid Hemorrhage

Objective: To determine the sensitivity of the initial new-generation CT (NGCT) scan interpretation for detection of acute nontraumatic subarachnoid hemorrhage (SAH) and to decide whether lumbar puncture (LP) should follow a "normal" NGCT scan.
Methods: A retrospective chart review was performed of patients admitted between March 1988 and July 1994 with proven SAH. Exclusion criteria were age <2 years, diagnosis other than acute SAH, history of head trauma within 24 hours before symptom onset, NGCT scan not done before diagnosis, and records not available. Patients were placed into two groups: symptom duration <24 hours (group 1) and >24 hours (group 2) prior to CT scan. The resolution of each NGCT scanner was recorded. An NGCT sceinner was defined as a third-generation scanner or more recent.
Results: Of 349 SAH patients, 181 met inclusion criteria. The sensitivity of NGCT scans for SAH was 93.1% for the group 1 patients ( n = 144) and 83.8% for the group 2 patients ( n = 37). The overall sensitivity was 91.2%. All the patients who had SAH not detected by NGCT scans were diagnosed by LP. There was no significant relationship between NGCT scanner resolution and sensitivity for SAH.
Conclusion: Initial interpretation of NGCT scans to detect SAH does not approach 100% sensitivity. A "normal" NGCT scan does not reliably exclude the need for LP in patients who have symptoms suggestive of SAH.     

Attitudes and Judgment of Emergency Physicians in the Management of Patients with Acute Headache

OBJECTIVES: There is little evidence guiding physicians in the evaluation of acute headache to rule out nontraumatic subarachnoid hemorrhage (SAH). The authors assessed emergency physicians in: 1) their pretest accuracy for predicting SAH, 2) their comfort with not ordering either head computed tomography (CT) or lumbar puncture (LP) in patients with acute headache, and 3) their comfort with not ordering head CT before performing LP in patients with acute headache. METHODS: This two-and-a-half-year prospective cohort study was conducted in three tertiary care university emergency departments with 51 emergency physicians. Consecutive patients more than 15 years of age with a nontraumatic, acute headache (onset to peak headache less than one hour) and normal results on neurologic examination were enrolled. Patients known to have cerebrospinal fluid shunt, aneurysm, or brain neoplasm, and patients with recurrent headaches of the same intensity/character as their current headache were excluded. Physicians recorded their pretest probability for SAH and their comfort with performing either no tests or an LP without first obtaining head CT. RESULTS: The authors enrolled 747 patients (mean age 42.8 years; 60.1% female; 77.0% their worst headache; 83.4% had CT and/or LP), including 50 (6.7%) with SAHs. Physicians reported being "uncomfortable" or "very uncomfortable" with performing no test in 75.4% of cases and being "uncomfortable" or "very uncomfortable" with performing LP without CT in 49.6% of cases. The area under the receiver operating characteristic (ROC) curve for SAH was 0.85 (95% CI = 0.80 to 0.91). CONCLUSIONS: Physicians were able to moderately discriminate SAH from other causes of headache before diagnostic testing.     

Prevalence of Herniation and Intracranial Shift on Cranial Tomography in Patients With Subarachnoid Hemorrhage and a Normal Neurologic Examination

Objectives: Patients frequently present to the emergency department (ED) with headache. Those with sudden severe headache are often evaluated for spontaneous subarachnoid hemorrhage (SAH) with noncontrast cranial computed tomography (CT) followed by lumbar puncture (LP). The authors postulated that in patients without neurologic symptoms or signs, physicians could forgo noncontrast cranial CT and proceed directly to LP. The authors sought to define the safety of this option by having senior neuroradiologists rereview all cranial CTs in a group of such patients for evidence of brain herniation or midline shift. Methods: This was a retrospective study that included all patients with a normal neurologic examination and nontraumatic SAH diagnosed by CT presenting to a tertiary care medical center from August 1, 2001, to December 31, 2004. Two neuroradiologists, blinded to clinical information and outcomes, rereviewed the initial ED head CT for evidence of herniation or midline shift. Results: Of the 172 patients who presented to the ED with spontaneous SAH diagnoses by cranial CT, 78 had normal neurologic examinations. Of these, 73 had initial ED CTs available for review. Four of the 73 (5%; 95% confidence interval [CI] = 2% to 13%) had evidence of brain herniation or midline shift, including three (4%; 95% CI = 1% to 12%) with herniation. In only one of these patients was herniation or shift noted on the initial radiology report. Conclusions: Awake and alert patients with a normal neurologic examination and SAH may have brain herniation and/or midline shift. Therefore, cranial CT should be obtained before LP in all patients with suspected SAH. ACADEMIC EMERGENCY MEDICINE 2010; 17:423–428 © 2010 by the Society for Academic Emergency Medicine     

Sudden onset headache: a prospective study of features,incidence and causes

Sudden onset headache is a common condition that sometimes indicates a life-threatening subarachnoid haemorrhage (SAH) but is mostly harmless. We have performed a prospective study of 137 consecutive patients with this kind of headache (thunderclap headache=TCH). The examination included a CT scan, CSF examination and follow-up of patients with no SAH during the period between 2 days and 12 months after the headache attack. The incidence was 43 per 100 000 inhabitants >18 years of age per year; 11.3% of the patients with TCH had SAH. Findings in other patients indicated cerebral infarction (five), intracerebral haematoma (three), aseptic meningitis (four), cerebral oedema (one) and sinus thrombosis (one). Thus no specific finding indicating the underlying cause of the TCH attack was found in the majority of the patients. A slightly increased prevalence of migraine was found in the non-SAH patients (28%). The attacks occurred in 11 cases (8%) during sexual activity and two of these had an SAH. Nausea, neck stiffness, occipital location and impaired consciousness were significantly more frequent with SAH but did not occur in all cases. Location in the temporal region and pressing headache quality were the only features that were more common in non-SAH patients. Recurrent attacks of TCH occurred in 24% of the non-SAH patients. No SAH occurred later in this group, nor in any of the other patients. It was concluded that attacks caused by a SAH cannot be distinguished from non-SAH attacks on clinical grounds. It is important that patients with their first TCH attack are investigated with CT and CSF examination to exclude SAH, meningitis or cerebral infarction. The results from this and previous studies indicate that it is not necessary to perform angiography in patients with a TCH attack, provided that no symptoms or signs indicate a possible brain lesion and a CT scan and CSF examination have not indicated SAH.     

老年性蛛网膜下腔出血非典型症状30例分析

CLINICAL DATA Subjects came from 30 patients with senile subarachnoid hemrrhagetreated in our hospital from January 1999 to December 2001 in-cluding 12 males and 18 females aged 60-78(mean: 65) yearsold. 24 patients presented with onset in action, 6 patients at rest; 26cases presented with acute onset and 4 cases subacute onset. Acuteheadache as first symptom was in 13 cases; pain at neck, waist,sacral as first symptom in 7 cases. 3 patients searched medical ser-vice for headache within 1 week; 2 patients for severe pain of bothlimbs and unable to walk; 2 patients for headache and vomiting at 2week. 7 patients were once treated out of our hospital and sciaticawas diagnosed in 4 cases, cold in 3 cases. Pain at shoulder, back,upper limb in action occurred in 2 cases as first symptom, consciousdisturbance was the first symptom in 4 cases, grand mal of epilepsyas first symptom in 3 cases. 1 patient searched medical service forright head pain, auricle pain for 20 days. Stiff neck ( + ) appeared in25 patients at hospitalization and (-) in 5 patients. 24 patientspresented with positive Kernig' s sign. 21 patients were complicatedwith hypertension, 1 patient was complicated with peripheral facialparalysis and left hemihypoesthesia, 3 patients with transient hemi-paresis of both lower limhs, 2 cases with bilateral ptosis, 1 case withexotropia of bilateral eyeball, pupil dilation, 6 cases with consciousdisturbance. Auxilliary examination: (1) Skull CT scanning: Sub-arachnoid hemorrhage was found in 20 cases, no abnormality in 7cases and 3 cases didn't undergo CT scanning. (2) Examination ofspinal fluid: patients with positive CT findings didn' t undergo lumbarpuncture, even hemic spinal fluid was found in 6 patients and yellowspinal fluid and shrinking red blood cell in 4 cases. Prognosis: Allcases were treated according to subarachnoid hemorrhage, 6 patientsdied and other 24 patients were cured after 6 - 8 weeks of treatment.     

Spinal intradural schwannoma presenting with acute subarachnoid hemorrhage: a case report and review of published reports

Acute subarachnoid hemorrhage (SAH) presentation is a very rare occurrence in spinal schwannomas. We report a case of lumbar schwannoma in a patient presenting first with acute SAH. A 40-year-old man was referred to our department 7 days after the sudden onset of headache, neck pain, and fever. SAH was suspected; however, head computed tomography (CT) findings were normal. A lumbar puncture indicated blood-stained cerebrospinal fluid (CSF). Moreover, the CSF pressure changed from 200 mmH₂O to 90 mmH₂O after drainage of 10 mL of CSF indicating a blockage of CSF. Subsequent magnetic resonance imaging (MRI) confirmed an intradural tumor with SAH, which also caused blockage of the CSF circulation. The patient underwent immediate surgery and fully recovered. In conclusion, the early diagnosis and total removal of the tumor and blood clot significantly improved the patient’s outcome. There is a high index of suspicion for spinal tumors resulting in SAH when there is a CSF pressure change after lumbar puncture in an SAH patient.     

Subarachnoid Hemorrhage Diagnosis: Lumbar Puncture Is Still Needed When the Computed Tomography Scan Is Normal

Objectives: To determine the sensitivity of third-generation CT scanners for diagnosed nontraumatic subarachnoid hemorrhage (SAH) and to assess the impact of symptom duration on sensitivity.
Methods: A retrospective chart review was performed in a university-affiliated tertiary care hospital with an annual ED volume of >100,000 patients. The target population was all patients who presented to the ED from January 1991 to September 1994 with symptoms suggestive of SAH and who had a final diagnosis of nontraumatic SAH based on either a positive CT scan or positive spinal fluid analysis. Patients referred from outside facilities were included if they had a CT done at the study site. All CT scans were done using third-generation scanners. Official CT scan reports were used to categorize scans as positive or negative.
Results: There were 140 patients identified with SAH, with a mean age of 56 years (range 10–88). The sensitivity of CT in the diagnosis of nontraumatic SAH when performed at or before 12 hours of symptom duration was 100% (80/80), and 81.7% (49/60) after 12 hours of symptom duration (95% CI 95–100% and 69.5–90.4%, respectively; p < 0.0001). Eleven of the 140 patients had a negative CT and positive spinal fluid analysis, yielding an overall sensitivity of 92.1% (129/140).
Conclusion: The sensitivity of third-generation CT scans for SAH decreases with time from the onset of symptoms. In this sample population, CT was able to detect all patients scanned ^12 hours after symptom onset. Although the study demonstrated good sensitivity of CT scan reports for SAH when the scan was performed after S12 hours of symptom onset, additional real-time experience is needed to better define the potential risk of a missed SAH should this population not receive the customary lumbar puncture examination in the setting of a negative CT scan.     

De-novo headache with transient vertebro-basilar symptoms: role of embryonic hypoglossal artery

We report the case of a 56-year-old man with acute onset of de-novo stabbing, pulsating and diffuse headache with subsequent appearance (within few minutes) of posterior fossa symptoms (vomiting, postural instability, anisocoria, incoordination, dysarthria, retropulsion) lasting 9–12 h. Recurrent hypertensive crises were detected during the acute observation in the Emergency Room, even in the absence of previous history of hypertension. Once subarachnoid hemorrhage and focal lesions (vascular and non-vascular) were excluded, brain computerized tomography-angiography and digital subtraction angiography disclosed the presence of left persistent primitive hypoglossal artery with bilateral vertebral artery hypoplasia and a slight aneurysmal dilation of the anterior communicating artery. Brain magnetic resonance study performed 24 h after onset of symptoms was negative for recent ischemic lesions. The clinical features of this rare vascular condition are discussed as a possible cause of magnetic resonance (diffusion weighted imaging) negative vertebro-basilar transient ischemic attack.     

Thunderclap headache: is it migraine?

In a prospective study, 14 out of 49 patients presenting to a Regional Neurosurgical Unit with sudden headache suggestive of subarachnoid haemorrhage had normal CSF and a normal CT scan: it did not prove possible, on clinical grounds alone, to distinguish these from those that had bled. We have now followed all these patients for a minimum of 18 months. Only one has had no further headache, 4 have had musculoskeletal pain, 5 psychogenic pain, and 4 migraine type symptoms. None went on to have an unequivocal subarachnoid haemorrhage, and we conclude that angiography cannot be justified in patients with this type of "thunderclap headache".     

Plasma endothelin in patients with acute aortic disease

On rare occasions, rupture of a cerebral aneurysm causes acute subdural hematoma (SDH) in addition to subarachnoid hemorrhage (SAH). The frequency of SDH resulting from aneurysmal rupture is summarized, and its clinical and radiological characteristics, as well as potential pitfalls in the diagnosis and the management of this life-threatening condition are described. Among 641 patients with nontraumatic SAH treated between 1992 and 2000, 12 patients (1.9%) presented with SDH due to aneurysmal rupture. The SAH grade on admission was grade II in one patient, grade IV in three patients, and grade V in eight patients. Four underwent both hematoma evacuation and clipping of the aneurysm, four underwent hematoma evacuation alone, and the other four patients were treated conservatively. The outcome was good recovery in two patients, severe disability in one patient, and death in nine patients. Patients with a good outcome had a better SAH grade on admission, smaller midline shift, and smaller SDH volume on the initial CT scan, and they had been treated by both SDH evacuation and clipping of the aneurysm. Emergency one-stage operations may be beneficial for aneurysmal SDH patients who are in good SAH grade, or those who are in poor SAH grade but show some neurological recovery after resuscitation. It should also be mentioned that there are cases of aneurysmal SDH without recognizable SAH on the CT scans, and that a case of aneurysmal SDH may present as a case of 'head trauma' after an accident, because of the disturbance of consciousness resulting from aneurysmal rupture.     

Lumbar Puncture First: An Alternative Model for the Investigation of Lone Acute Sudden Headache

Subarachnoid hemorrhage (SAH) is a diagnosis often considered in patients presenting to the ED with acute sudden headaches, but with normal physical examinations. Standard of care today is for these patients to be investigated by noncontrast CT scan followed by lumbar puncture (LP) for negative CTs. However, given that most investigated patients have benign headaches, most of the CT and LP results are normal. The authors studied, by means of a theoretical analysis, the impact of an alternative diagnostic model, in which LP would be the first (and, in most cases, only) diagnostic test for patients suspected of SAH who met lone acute sudden headache (LASH) criteria. Given reasonable assumptions, for every 100 patients investigated, the "LP-first" model would result in 79 to 83 fewer CT scans and only seven to 11 additional LPs, as compared with traditional strategies. Among ED headache patients meeting LASH criteria, the authors believe use of this model could result in more efficient use of resources, minimal additional morbidity, and equal diagnostic accuracy for SAH.     

Aneurysmal subarachnoid hemorrhage: update for emergency physicians

Aneurysmal subarachnoid hemorrhage (SAH) is a serious cause of stroke that affects 30,000 patients in North America annually. Due to a wide spectrum of presentations, misdiagnosis of SAH has been reported to occur in a significant proportion of cases. Headache, the most common chief complaint, may be an isolated finding; the neurological examination may be normal and neck stiffness absent. Emergency physicians must decide which patients to evaluate beyond history and physical examination. This evaluation--computed tomography (CT) scanning and lumbar puncture (LP)--is straightforward, but each test has important limitations. CT sensitivity falls with time from onset of symptoms and is lower in mildly affected patients. Traumatic LP must be distinguished from true SAH. Cerebrospinal fluid analysis centers on measuring xanthochromia. Debate exists about the best method to measure it--visual inspection or spectrophotometry. An LP-first strategy is also discussed. If SAH is diagnosed, the priority shifts to specialist consultation and cerebrovascular imaging to define the offending vascular lesion. The sensitivity of CT and magnetic resonance angiography are approaching that of conventional catheter angiography. Emergency physicians must also address various management issues to treat or prevent early complications. Endovascular therapy is being increasingly used, and disposition to neurovascular centers that offer the full range of treatments leads to better patient outcomes. Emergency physicians must be expert in the diagnosis and initial stabilization of patients with SAH. Treatment in a hospital with both neurosurgical and endovascular capability is becoming the norm.     

Sudden onset of vomiting as a presentation of perimesencephalic subarachnoid haemorrhage.

Subarachnoid haemorrhage (SAH) makes up 1% of all attendances for acute severe headache to emergency departments, but other less common presentations may be seen. A 28-year-old man presented to the ED complaining of a 24-h history of nausea and vomiting of sudden onset, but without headache. The patient also described mild photophobia and neck stiffness. A computed tomography scan revealed perimesencephalic blood, and a subsequent angiogram was negative. This appearance is seen in cases of non-aneurysmal SAH, which often occur in younger, male, normotensive patients, and give rise to few warning symptoms. A high index of suspicion should be maintained for SAH, even in the absence of headache.     

The risks of sumatriptan administration in patients with unrecognized subarachnoid haemorrhage (SAH)

Administration of sumatriptan in subarachnoid haemorrhage (SAH) patients, misdiagnosed as migraine patients, may induce symptomatic cerebral vasospasm with potentially dangerous consequences. Over a 5-year period, we observed three patients with a 3-15-year history of migraine, who received sumatriptan for acute headache. Two patients received 6 mg sumatriptan subcutaneously on days 4 and 6, and one patient 3 x 100 mg sumatriptan orally on day 1 after an acute headache episode. In all three cases, an alleviation of headache intensity from severe to moderate was observed. When headache recurred and meningeal signs appeared, SAH was diagnosed by computed tomography in all three cases. No neurological deficits occurred during the further course of the disease. In both patients with a SAH caused by an aneurysm, transcranial Doppler sonography demonstrated vasospasm of the basal cerebral arteries. An antinociceptive effect of sumatriptan can be observed in SAH patients in good clinical condition, which suggests a specific craniovascular antinociceptive action. This may lead to misdiagnosis as migraine and delayed appropriate diagnosis and treatment.