Importance of the recognition of a warning leak as a sign of a ruptured intracranial aneurysm

Prospective Implementation of the Ottawa Subarachnoid Hemorrhage Rule and 6-Hour Computed Tomography Rule

Background and Purpose- The Ottawa subarachnoid hemorrhage (SAH) rule identifies patients with headache requiring no testing for SAH, while the 6-hour computed tomography (CT) rule guides when to forgo a lumbar puncture. Our objectives were to: (1) estimate the clinical impact of the Ottawa SAH rule and the 6-hour-CT rule on testing rates (ie, CT, lumbar puncture, CT angiography); (2) validate the 6-hour-CT rule for SAH when applied prospectively in a new cohort of patients. Methods- We conducted a multicenter prospective before/after implementation study from 2011 to 2016 with 6 months follow-up at 6 tertiary-care Canadian Academic Emergency Departments. Consecutive alert, neurologically intact adults with headache were included. For intervention period, physicians were given a 1-hour lecture, pocket cards, posters were installed, and physicians indicated Ottawa SAH rule criteria when ordering CTs. SAH was defined by blood on CT, xanthochromia in cerebrospinal fluid, or >1×10⁶/L red blood cells in cerebrospinal fluid with aneurysm. Results- We enrolled 3672 patients, 1743 before and 1929 after implementation, including 188 with SAH. Proportions undergoing CT was unchanged (88.0% versus 87.5%; P=0.643). Lumbar puncture use decreased (38.9% versus 25.9%; P<0.0001). Additional testing following CT (ie, lumbar puncture or CT angiography) decreased (51.3% versus 42.2%; P<0.0001). Admissions declined (9.8% versus 7.4%; P=0.011). Mean emergency department stay was unchanged (6.3±4.0 versus 6.4±4.2 hours; P=0.685). The Ottawa SAH rule was 100% (95% CI, 98.1%-100%) sensitive, and the 6-hour-CT rule was 95.5% (95% CI, 89.8-98.5) sensitive for SAH. The 6-hour-CT rule missed 5 SAHs: 1 radiology misread, 2 incidental aneurysms, 1 nonaneurysmal cause, and 1 profoundly anemic patient. Conclusions- The Ottawa SAH rule and the 6-hour-CT rule are highly sensitive and can be used routinely when SAH is considered in patients with headache. Implementing both rules was associated with a meaningful decrease in testing and admissions to hospital.

Management of anesthesia for cesarean delivery in a patient with an unruptured intracranial aneurysm

Headaches are a common symptom during pregnancy. The thunderclap headache is a sudden onset headache reaching maximal intensity within seconds to minutes. It is typically a subarachnoid hemorrhage caused by rupture of an intracranial aneurysm or arteriovenous malformation. Physiologic changes of pregnancy, such as increased cardiac output and plasma volume, may increase the risk of aneurysmal rupture. The relationship between the mode of delivery and incidence of rupture is not well defined. In this case report, we discuss the anesthetic management for cesarean delivery of a parturient with an unruptured aneurysm, located on the left ophthalmic-internal carotid artery. The delivery options and anesthetic technique used are presented, together with a review of published literature.

Ultra-Early Angiographic Vasospasm After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

OBJECTIVE

After aneurysmal subarachnoid hemorrhage (aSAH), prognosis is affected heavily by the presence of delayed cerebral ischemia (DCI). There is growing recognition of ultra-early angiographic vasospasm (UEAV) occurring within 48 hours of aSAH; however, its relationship with DCI and ultimately prognosis remains unclear.

METHODS

Various databases limited to the English language through September 2016 were searched systematically. Eligible studies were those comparing UEAV with control non-UEAV outcomes and follow-up. Two independent reviewers evaluated the quality of studies and abstracted the data, with discrepancies resolved by a third. We calculated odds ratios (ORs) and 95% confidence intervals for all outcomes by using random-effects meta-analyses and performed a heterogeneity analysis.

RESULTS

Four comparative studies were selected for analysis. Pooled analysis demonstrated that UEAV compared with no-UEAV was associated with greater proportion of rupture aneurysms sized greater than 12 mm (38.3% vs. 24.3%, P < 0.00001). A significantly greater number of patients with UEAV had ruptured MCA aneurysms compared with patients without UEAV (29.7% vs. 19.9%, P = 0.005). Compared with no-UEAV, patients with UEAV were significantly associated with symptomatic cerebral vasospasm (OR 2.07, P = 0.05) and DCI/infarction (OR 2.52, P = 0.02). A significant association also was found between UEAV and an unfavorable outcome at follow-up (OR 1.64, P = 0.03) and greater mortality (OR 2.65, P < 0.00001).

CONCLUSIONS

UEAV was significantly associated with symptomatic cerebral vasospasm, DCI/infarction, unfavorable outcome at follow-up, and greater mortality. Patients with intracerebral hematoma, intraventricular hemorrhage (Fisher Grade IV), larger ruptured aneurysms >12 mm, and an MCA location were more likely to have UEAV.

Sentinel Headaches in Aneurysmal Subarachnoid Haemorrhage: What is the True Incidence? A Systematic Review

The aim of this systematic review was to determine the incidence of sentinel headache reported by patients with aneurysmal subarachnoid haemorrhage, and whether they are likely to be due to recall bias or to misdiagnosis of a previous haemorrhage. Nine studies of good quality, which reported the number of patients with aneurysmal subarachnoid haemorrhage with a history of sentinel headache, gave rates of 10% to 43%. Two case-control studies, in which the frequency of a history of sentinel headache in patients with aneurysmal subarachnoid haemorrhage was compared with that in controls with non-aneurysmal subarachnoid haemorrhage or with stroke, gave an incidence of 5% (95% confidence interval 0.5, 16) in controls, suggesting that only a small number of apparent sentinel headaches are due to recall bias. Sentinel headaches appear to be a real entity. Their true incidence may vary from near zero to about 40% according to the rate of misdiagnosis in the community under consideration.

Ultra-early angiographic vasospasm associated with delayed cerebral ischemia and infarction following aneurysmal subarachnoid hemorrhage

OBJECTIVE The clinical significance of cerebral ultra-early angiographic vasospasm (UEAV), defined as cerebral arterial narrowing within the first 48 hours of aneurysmal subarachnoid hemorrhage (aSAH), remains poorly characterized. The authors sought to determine its frequency, predictors, and impact on functional outcome. METHODS The authors prospectively studied UEAV in a cohort of 1286 consecutively admitted patients with aSAH between August 1996 and June 2013. Admission clinical, radiographic, and acute clinical course information was documented during patient hospitalization. Functional outcome was assessed at 3 months using the modified Rankin Scale. Logistic regression and Cox proportional hazards models were generated to assess predictors of UEAV and its relationship to delayed cerebral ischemia (DCI) and outcome. Multiple imputation methods were used to address data lost to follow-up. RESULTS The cohort incidence rate of UEAV was 4.6%. Multivariable logistic regression analysis revealed that younger age, sentinel bleed, and poor admission clinical grade were significantly associated with UEAV. Patients with UEAV had a 2-fold increased risk of DCI (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.4-3.9, p = 0.002) and cerebral infarction (OR 2.0, 95% CI 1.0-3.9, p = 0.04), after adjusting for known predictors. Excluding patients who experienced sentinel bleeding did not change this effect. Patients with UEAV also had a significantly higher hazard for DCI in a multivariable model. UEAV was not found to be significantly associated with poor functional outcome (OR 0.8, 95% CI 0.4-1.6, p = 0.5). CONCLUSIONS UEAV may be less frequent than has been reported previously. Patients who exhibit UEAV are at higher risk for refractory DCI that results in cerebral infarction. These patients may benefit from earlier monitoring for signs of DCI and more aggressive treatment. Further study is needed to determine the long-term functional significance of UEAV.

Neuroradiologic Diagnosis of Minor Leak prior to Major SAH: Diagnosis by T1-FLAIR Mismatch

BACKGROUND AND PURPOSE

In major SAH, the only method to diagnose a preceding minor leak is to ascertain the presence of a warning headache by interview; however, poor clinical condition and recall bias can cause inaccuracy. We devised a neuroradiologic method to diagnose previous minor leak in patients with SAH and attempted to determine whether warning (sentinel) headaches were associated with minor leaks before major SAH.

MATERIALS AND METHODS

We retrospectively evaluated 127 patients who were admitted with SAH within 48 hours of ictus. Previous minor leak before major SAH was defined as T1WI-detected clearly bright hyperintense subarachnoid blood accompanied by SAH blood on FLAIR images that was distributed over a larger area than bright hyperintense subarachnoid blood on T1WI (T1-FLAIR mismatch).

RESULTS

The incidence of warning headache before SAH was 11.0% (14 of 127 patients, determined by interview). The incidence of T1-FLAIR mismatch (neuroradiologic diagnosis of minor leak before major SAH) was 33.9% (43 of 127 patients). Of the 14 patients with warning headache, 13 had a minor leak diagnosed by T1-FLAIR mismatch at the time of admission. Variables identified by multivariate analysis as significantly associated with minor leak diagnosed by T1-FLAIR mismatch included 80 years of age or older, rebleeding after admission, intracerebral hemorrhage on CT, and mRS scores of 3-6.

CONCLUSIONS

We conclude that warning headaches diagnosed by interview are not a product of recall bias but are the result of actual leaks from aneurysms.

Cerebral aneurysm presenting with aseptic meningitis: a case report

Introduction

This case highlights the potential importance of new-onset headache, even in the absence of other worrisome features, in a patient with a cerebral aneurysm.

Case presentation

A 61-year-old Caucasian woman presented with nonspecific insidious onset of headache, a superior cerebellar artery aneurysm and cerebrospinal fluid lymphocytosis. She had a subarachnoid hemorrhage 21 days later, at which time the aneurysm had enlarged. The aneurysm was repaired endovascularly and the patient recovered with a modified Rankin score of 1.

Conclusions

This case suggests that new onset of chronic headache in a patient with an unruptured aneurysm may be due to aneurysm growth and can be associated with cerebrospinal fluid lymphocytosis. Headaches are common and may occur incidentally in patients with cerebral aneurysms, but new-onset headache, even if mild, should prompt consideration for timely aneurysm repair.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Both Surgical Clipping and Endovascular Embolization of Unruptured Intracranial Aneurysms Are Associated With Long-term Improvement in Self-Reported Quantitative Headache Scores

BACKGROUND:

The most common presenting symptom for unruptured intracranial aneurysms (UIAs) is headache (HA). However, most experts believe that UIAs associated with HAs are unrelated and incidental.

OBJECTIVE:

To analyze the incidence and characterization of HAs in patients with UIAs before and after treatment with either surgical clipping or endovascular embolization.

METHOD:

We prospectively determined the presence, sidedness, and severity of HAs preoperatively in patients who presented to the senior author with a UIA. A validated, quantitative 11-point HA pain scale was used in all patients. The same HA assessments were performed again on these patients an average of 32.4 months postoperatively.

RESULTS:

In this study, 92.45% (n = 53) of patents for whom we were able to obtain both a preoperative and postoperative pain score had an improvement in their HAs. The average quantitative HA score was 5.87 preoperatively vs 1.39 postoperatively (P &lt; .001). There was no relationship found between the following: (1) HA severity vs aneurysm size, (2) sidedness of aneurysm vs sidedness of HA, and (3) HA improvement after surgical vs endovascular treatment.

CONCLUSION:

This study suggests that surgical and endovascular treatment of a UIA is associated with dramatic improvement in self-reported HA score an average of 32.4 months postoperatively.

Spectrum of dizziness visits to US emergency departments: cross-sectional analysis from a nationally representative sample

OBJECTIVE

To describe the spectrum of visits to US emergency departments (EDs) for acute dizziness and determine whether ED patients with dizziness are diagnosed as having a range of benign and dangerous medical disorders, rather than predominantly vestibular ones.

PATIENTS AND METHODS

A cross-sectional study of ED visits from the National Hospital Ambulatory Medical Care Survey (NHAMCS) used a weighted sample of US ED visits (1993-2005) to measure patient and hospital demographics, ED diagnoses, and resource use in cases vs controls without dizziness. Dizziness in patients 16 years or older was defined as an NHAMCS reason-for-visit code of dizziness/vertigo (1225.0) or a final International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis of dizziness/vertigo (780.4) or of a vestibular disorder (386.x).

RESULTS

A total of 9472 dizziness cases (3.3% of visits) were sampled over 13 years (weighted 33.6 million). Top diagnostic groups were otologic/vestibular (32.9%), cardiovascular (21.1%), respiratory (11.5%), neurologic (11.2%, including 4% cerebrovascular), metabolic (11.0%), injury/poisoning (10.6%), psychiatric (7.2%), digestive (7.0%), genitourinary (5.1%), and infectious (2.9%). Nearly half of the cases (49.2%) were given a medical diagnosis, and 22.1% were given only a symptom diagnosis. Predefined dangerous disorders were diagnosed in 15%, especially among those older than 50 years (20.9% vs 9.3%; P<.001). Dizziness cases were evaluated longer (mean 4.0 vs 3.4 hours), imaged disproportionately (18.0% vs 6.9% undergoing computed tomography or magnetic resonance imaging), and admitted more often (18.8% vs 14.8%) (all P<.001).

CONCLUSION

Dizziness is not attributed to a vestibular disorder in most ED cases and often is associated with cardiovascular or other medical causes, including dangerous ones. Resource use is substantial, yet many patients remain undiagnosed.

Comparison of Magnetic Resonance Imaging Sequences With Computed Tomography to Detect Low-Grade Subarachnoid Hemorrhage

OBJECTIVES

To compare computed tomography (CT) with magnetic resonance imaging (MRI) for the presumptive diagnosis and localization of acute and subacute low-grade subarachnoid hemorrhage (SAH).

METHODS

We consecutively enrolled 45 patients clinically suspected of low-grade SAH, comparing them with a control group. We obtained axial nonenhanced CT scans as well as fluid-attenuated inversion recovery (FLAIR) and T2-weighted gradient echo (T2*) MRI sequences at 1.0 T. Two neuroradiologists scrutinized the presence of blood at 26 different regions in the intracranial subarachnoid space (SAS).

RESULTS

Three of 45 patients had normal CT and MRI scans, and SAH was excluded by lumbar puncture. We demonstrated SAH on CT scans in 28 of 42 (66.6%) patients, T2* sequences in 15 of 42 (35.7%) patients, and FLAIR sequences in 42 of 42 (100%) patients. Fluid-attenuated inversion recovery sequences were superior to CT in 16 of the 26 evaluated regions.

CONCLUSIONS

The FLAIR sequence was superior for presumptive diagnosis and localization of acute and subacute low-grade SAH, representing a potential tool in this setting.

Comparison of prognosis and complications after warning leaks in subarachnoidal hemorrhage--experience with 214 patients following aneurysm clipping

OBJECTIVES

The 'warning leak', a smaller bleeding event from an aneurysm, which sometimes occurs before an acute massive subarachnoidal hemorrhage (SAH), was first described in 1967. The present study was performed to compare the complications and prognosis for 214 patients with and without a warning leak; aneurysm clipping had been performed in all.

METHODS

The interval between the warning headache and the actual SAH was calculated. The following complications were examined: preoperative hemorrhage, intra-operative rupture of the aneurysm, postoperative re-bleeding, symptomatic vasospasm, shunt-requiring hydrocephalus, ventriculitis, postoperative wound infection, and outcome according to the Glasgow Outcome Scale (GOS).

RESULTS

Sixty-seven (31%) out of the 214 patients had a warning leak with a median distance of 11 days before suffering from major SAH. Preoperative angiographic vasospasms occurred more frequently in the group with a warning bleeding (22.4 versus 6.1%; p<0.05), which means that the warning leaks induce vascular reactions similar to SAH. The outcome of both groups after a mean follow-up time of 22 months did not show any difference. But 30 out of the 67 patients with a warning leak were graded H&H III-V at admission to hospital after a major SAH. The overall outcome for patients graded H&H I and II was in 92% favorable, compared with only a 54% favorable outcome for H&H III-V patients. Long-term outcome in the warning leak group was not impaired by angiographically proven vasospasm.

DISCUSSION

To give patients the chance to start their treatment in a better clinical condition it is important to recognize the early warning signs.

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.

Resolution of cluster headache after closure of an anterior communicating artery aneurysm: the role of pericarotid sympathetic fibres

We report the case of a patient suffering from migraine without aura since childhood who, at the age of 58 years, developed cluster headache (CH) attacks. This second type of headache was related to an aneurysm of the anterior communicating artery (ACoA) whose bursting caused subarachnoid haemorrhage. The aneurysm's clipping made the cluster headache subside and there was no recurrence for almost four years. However, nine months after haemorrhage, the patient experienced new migraine without aura attacks. As a pathogenetic interpretation of this secondary cluster headache, we discuss the possible role of pericarotid sympathetic nerves in cluster headache attacks. We suggest that the surgical dissection of the pericarotid sympathetic fibres could prevent the onset of the cluster headache attacks by cutting part of the circuit underlying it.

Céphalées dans un contexte d’urgence

Headaches constitute one of the most frequent reason of consultation. Their causes are extremely varied. The first step consists in the analysis of the characteristics of the pain and the associated signs in order to distinguish primary and secondary headaches. Primary headaches, including migraines and tension-type headaches are the most frequent types and do not require imaging evaluation. Secondary headaches are related to an organic cause and require specific investigations. In case of suspected symptomatic or secondary headaches, brain imaging plays an important role in the etiologic work-up. The main purpose of imaging in an emergency setting is to diagnose a life-threatening disease.

Evidence‐Based Diagnosis of Nontraumatic Headache in the Emergency Department: A Consensus Statement on Four Clinical Scenarios

OBJECTIVE

To provide to emergency department (ED) physicians with guidelines for diagnosis of patients with nontraumatic headaches.

BACKGROUND

Many patients present to an ED with the chief complaint of headache. Causes of nontraumatic headache include life-threatening illnesses, and distinguishing patients with such ominous headaches from those with a primary headache disorder can be challenging for the ED physician.

CONCLUSION

We present a consensus statement aimed to be a useful tool for ED doctors in making evidence-based diagnostic decisions in the management of adult patients with nontraumatic headache.

METHODS

A multidisciplinary work performed an extensive review of the medical literature and applied the information obtained to commonly encountered scenarios in the ED.

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.

Thunderclap headache

Thunderclap headache refers to an excruciating headache of instantaneous onset. It occurs as suddenly and unexpectedly as a "clap of thunder." Patients with thunderclap headache may have normal neurologic examination results and normal computed tomographic brain scans, even if they have serious underlying pathology. This has created confusion regarding nosology and the nature and extent of the diagnostic evaluation, which this article discusses.

Thunderclap headache

The aim is to review the background underlying the debate related to the alternative nomenclatures for and the most appropriate diagnostic evaluation of patients with thunderclap headache. The clinical profile and differential diagnosis of thunderclap headache is described, and a nosological framework and diagnostic approach to this group of patients is proposed.

The notion of "warning leaks" in subarachnoid haemorrhage: are such patients in fact admitted with a rebleed?

OBJECTIVE

Often patients with subarachnoid haemorrhage (SAH) recall a recent episode of acute severe headache, usually interpreted as a "warning headache" or first SAH. An alternative explanation is recall bias. The clinical and radiological features of patients with SAH were studied in relation to previous headaches or later rebleeding.

METHODS

Patients with either a previous headache episode or a subsequent rebleed were selected from the SAH database in Utrecht within 1 month of the index SAH. The clinical condition was graded on the World Federation of Neurological Surgeons (WFNS) scale. The CT was reviewed and the amounts of subarachnoid blood, hydrocephalus, and intraventricular, intracerebral, and subdural blood were rated. Proportions were compared by unpaired or paired t test.

RESULTS

Forty four of 390 patients (11%) had had a severe headache before their index SAH (11 of these had a subsequent rebleed); 31 other patients had a rebleed in hospital but no preceding headache. Patients with and without preceding headache did not differ in level of consciousness (14 of 44 v 11 of 31 were comatose), nor in any of the radiological features. After rebleeding (42 patients), 37 of 42 patients were comatose (v 11 of 42 before), and CT showed higher proportions of intracerebral haemorrhage (17%), intraventricular haemorrhage, (27%), and hydrocephalus (12%) than baseline scans. Intraventricular haemorrhage was twice as frequent after rebleeding than at baseline.

CONCLUSIONS

The clinical and radiological features of patients admitted with SAH after a preceding bout of headache did not differ from those without such an episode, and are clearly dissimilar from those after documented rebleeds. The findings challenge the existence of minor "warning headaches".

Unruptured cerebral aneurysm producing a thunderclap headache

A sudden and severe headache is the most common presentation of an acutely ruptured cerebral aneurysm. A similar headache in the absence of subarachnoid blood has rarely been ascribed to an unruptured cerebral aneurysm, but may result from acute aneurysm expansion and indicate a high risk of future rupture. We present a patient who developed a sudden, severe, "thunderclap" headache, with no associated neurological deficit. Computed tomogram and lumbar cerebral spinal fluid obtained 5.5 hours after headache onset were negative for subarachnoid hemorrhage. The patient underwent cerebral angiography which revealed a posterior communicating artery aneurysm with an associated daughter aneurysm. Craniotomy and clip obliteration of the aneurysm were performed. The aneurysm dome was very thin and there was no evidence of recent or old hemorrhage. A "thunderclap" headache without subarachnoid hemorrhage may be an important harbinger of a cerebral aneurysm with the potential for future rupture. Early recognition and neurovascular imaging of aneurysms presenting in this rare fashion are warranted.

Risks of surgery for patients with unruptured intracranial aneurysms

BACKGROUND

With the widespread use of less invasive imaging tools, such as magnetic resonance angiography and computed tomographic angiography, unruptured cerebral aneurysms are found much more often than in the past. This retrospective study was undertaken to determine the risk factors for surgical intervention in a patient with an unruptured intracranial aneurysm.

METHODS

Over a 5-year period, 1,558 patients with intracranial aneurysms underwent surgery at our center. Of these, 310 patients (20%) with unruptured aneurysms were included in this study.

RESULTS

Out of 310 patients with unruptured aneurysms, 292 (95%) had a favorable outcome, and only one patient (0.3%) with a giant vertebral artery aneurysm died. Aneurysm size larger than 15 mm and location of the aneurysm in the posterior circulation were independent risk factors associated with less favorable outcomes. Patients with a single aneurysm had a better outcome than did patients with multiple aneurysms.

CONCLUSION

Our results support the contention that surgical treatment of unruptured intracranial aneurysms carries a low risk of morbidity and mortality and may improve the outcome in patients harboring cerebral aneurysms by preventing the devastating effects of subarachnoid hemorrhage. Aneurysm size, location, and number were risk predictors for surgical morbidity in patients with unruptured aneurysms.

Aneurysm size: a prognostic factor for rupture

For effective management of patients with unruptured intracranial aneurysms, prognostic criteria for rupture are needed, of which aneurysm size is a key factor. However, the critical size at which an aneurysm becomes hazardous is not known. During the last 5 years, 1558 aneurysm patients have been operated on in our centre. Of these 1248 presented with a subarachnoid haemorrhage (ruptured aneurysms) and 310 without a subarachnoid haemorrhage (unruptured aneurysms). Of the ruptured aneurysms 475 (38%) were small in size with a maximum diameter < 6 mm. Most of these small ruptured aneurysms were located on the anterior communicating artery. Of the 310 patients with unruptured aneurysms 253 (81.6%) had single aneurysms; 113 (44.7%) of those were small in size. Most of these small unruptured aneurysms were located on the middle cerebral artery. The remaining 57 patients with unruptured aneurysms harboured multiple aneurysms totalling 116 aneurysms; 50% of them were small in size. Our of 160 patients with multiple aneurysms presenting with subarachnoid haemorrhage, 34 patients had small aneurysm(s) accompanied with medium or large sized aneurysm(s); in nine (26.5%) of these 34 patients the small aneurysm was the ruptured one. These data suggest that small aneurysms < 6 mm in diameter are not innocuous and hazardous, and surgical treatment should be considered for small unruptured aneurysms even if they are less than 6 mm in diameter.

Warning leak and management outcome in aneurysmal subarachnoid hemorrhage

The impact of warning leaks on management results in patients with aneurysmal subarachnoid hemorrhage (SAH) was evaluated in this prospective study. In a consecutive series of 422 patients with aneurysmal SAH, 84 patients (19.9%) had an episode suggesting a warning leak; 34 (40.5%) of these patients were seen by a physician without the condition being recognized. The warning leak occurred less than 2 weeks before a major SAH in 75% of the patients. A good outcome was experienced by 53.6% of patients who had a warning leak versus 63.3% of those who had no warning leak. In a subgroup of patients who had an interval of 3 days or less from warning leak to SAH, only 36.4% had a good outcome. The proportion of patients in good neurological condition (Hunt and Hess Grades I and II) who had a good outcome was 88.1% in the group with no warning leak versus 53.6% in the group whose SAH was preceded by a warning leak. A difference of 35% between these two groups reflects the impact of an undiagnosed warning leak on patient outcome, based on the assumption that patients with a warning leak had clinical conditions no worse than Hunt and Hess Grade II at the time of the episode. In the subgroup of patients with the short interval between warning leak and SAH, the difference was almost 52%. The difference in outcome also reflects the potential improvement in outcome that can be achieved by a correct diagnosis of the warning leak. If the correct diagnosis is made in patients seeking medical attention due to a warning leak, favorable outcomes in the overall management of aneurysmal SAH are estimated to increase by 2.8%. An active diagnostic attitude toward patients experiencing a sudden and severe headache is warranted as it offers a means of improving overall outcome in patients with SAH.

Misdiagnosis of symptomatic cerebral aneurysm. Prevalence and correlation with outcome at four institutions

BACKGROUND AND PURPOSE

It is not known what fraction of patients with symptomatic cerebral aneurysms are misdiagnosed at initial medical presentation. It is also not clear whether misdiagnosed patients more frequently deteriorate before definitive aneurysm diagnosis and therapy or achieve a poorer outcome than correctly diagnosed patients.

METHODS

We reviewed records of consecutive patients with symptomatic cerebral aneurysms managed by four tertiary-care neurosurgical services during a recent 19-month period. Clinical course and outcome were analyzed according to misdiagnosis or correct diagnosis at initial medical evaluation.

RESULTS

Fifty-four of 217 patients (25%) were misdiagnosed at initial medical evaluation, including 46 of 121 patients (38%) initially in good clinical condition (clinical grade 1 or 2). Forty-six of 54 patients (85%) in the misdiagnosis group were initially grade 1 or 2 compared with 75 of 163 patients (46%) with correct initial diagnosis (P < .01). Twenty-six of 54 misdiagnosed patients (48%) deteriorated or rebled before definitive aneurysm treatment compared with 4 of 165 correctly diagnosed patients (2%) (P < .001). Among patients initially presenting as clinical grade 1 or 2, overall good or excellent outcome was achieved in 91% of those with correct initial diagnosis and 53% of patients with initial misdiagnosis (P < .001). Deterioration before correct diagnosis accounted for 16 of 67 patients (24%) with poor or worse final outcome in this series.

CONCLUSIONS

Patients in good clinical condition with symptomatic cerebral aneurysms were commonly misdiagnosed. Misdiagnosed patients were more likely than correctly diagnosed patients to deteriorate clinically and had a worse overall outcome. Misdiagnosed cases accounted for a significant fraction of overall poor outcomes among consecutive cases of symptomatic aneurysms.

Will increased awareness among physicians of the significance of sudden agonizing headache affect the outcome of subarachnoid hemorrhage? Coventry and Warwickshire Study: audit of subarachnoid hemorrhage (establishing historical controls), hypothesis, campaign layout, and cost estimation

BACKGROUND AND PURPOSE

The most common symptom associated with aneurysmal minor bleed ("warning leak") is a sudden agonizing headache. Early screening of these patients may improve the outcome of subarachnoid hemorrhage and may be highly cost-effective.

METHODS

We conducted an extensive retrospective audit of subarachnoid hemorrhage over the last 10 years in the region of Coventry and Warwickshire, England, and initiated a continuous campaign among all physicians in the region for early neurosurgical referral of patients with sudden agonizing headache.

RESULTS

Over the last 10 years the incidence of subarachnoid hemorrhage in the region was 8.7/100 000 per year. Surgical activity was 34% and early mortality 45.2%. Functional outcome, both overall and by grade on admission, was within internationally accepted levels. Warning leak symptoms before admission were experienced by 20% of patients. These patients sought medical advice but were not referred immediately to the neurosurgical unit.

CONCLUSIONS

We have established our population as valid historical controls and outlined our campaign strategy. Lowering the clinical threshold at which patients with sudden agonizing headache are screened for aneurysms or arteriovenous malformations will undoubtedly increase diagnostic costs. However, for reasons given in the text, we estimated the cost per quality-adjusted life year gain to be 1000 pounds ($1500).

Diagnostic testing for the evaluation of headaches

Headaches are one of the most common symptoms that neurologists evaluate. Although most are caused by primary disorders, the list differential diagnoses is one of the longest in all of medicine, with over 300 different types and causes. The cause or type of most headaches can be determined by a careful history supplemented by a general and neurologic examination. Reasons for obtaining neuroimaging include medical indications as well as anxiety of patients and families and medico-legal concerns. In the era of managed care, concerns over deselection and negative capitation may dissuade the physician from ordering even a medically indicated scan. The yield of neuroimaging in the evaluation of patients with headache and a normal neurologic examination is quite low. Combining the results of multiple studies performed since 1977 for a total of 3026 scans reveals the overall percentages of various pathologies as: brain tumors, 0.8%; arteriovenous malformations, 0.2%; hydrocephalus, 0.3%; aneurysm, 0.1%; subdural hematoma, 0.2%; and strokes, including chronic ischemic processes, 1.2%. EEG is not useful in the routine evaluation of patients with headache. Similarly, the yield of neuroimaging in the evaluation of migraine is quite low. Combining the results of multiple studies performed since 1976 for a total of 1440 scans of patients with various types of migraine, the overall percentages of various pathologies are: brain tumor, 0.3%; arteriovenous malformation, 0.07%; and saccular aneurysm, 0.07%. WMA have been reported on MRI studies of patients with all types of migraine, with a range from 12% to 46%. The cause of WMA in migraine is not certain. Cerebral atrophy has been variable reported as more frequent and no more frequent in migraineurs compared with controls. The "first or worst" headache has a long list of possible causes and always includes the possibility of acute subarachnoid hemorrhage. Headaches--especially the sentinel type caused by SAH--often are misdiagnosed. The probability of detecting an aneurysmal hemorrhage of CT scans performed at various intervals after the ictus is: day 0.95%; day 3, 74%; 1 week, 50%; 2 weeks, 30%; and 3 weeks, almost nil. The location of a ruptured saccular aneurysm often is suggested by the predominant site of the SAH. The probability of detecting xanthochromia with spectrophotometry in the CSF at various times after a subarachnoid hemorrhage is: 12 hours, 100%; 1 week, 100%; 2 weeks, 100%; 3 weeks, more than 70%; and 4 weeks, more than 40%. The management of thunderclap headaches with normal CT scan and CSF examinations is controversial. Most patients have a benign course but an unruptured saccular aneurysm occasionally may be responsible for the headache. MR angiography may be a reasonable test to obtain instead of a cerebral arteriogram in many of these cases. About 30% to 90% of patients have headaches of various types and causes after mild head injury. Although most headaches are relatively benign, perhaps 1% to 3% of these patients have life-threatening pathology, including subdural and epidural hematomas, that are detected on CT and MRI scans. Headaches caused by subdural hematomas can be nonspecific. When new-onset headaches begin in patients over the age of 50 years, the physician always should consider whether it may be a secondary headache disorder requiring specific diagnostic testing and treatment. Up to 15% of patients 65 years and over who present to neurologists with new-onset headaches may have serious pathology such as stroke, TA, neoplasm, and subdural hematoma. Headaches are the most common symptom of TA, reported by 60% to 90%. The only over the temple. The diagnosis of TA is based on a high index of clinical suspicion that usually but not always is confirmed by laboratory testing. The erythrocyte sedimentation rate can be normal in 10% to 36% of patients with TA. A superficial temporal artery biopsy can give a false-negative result in 5% to 44% of patients.

Prospective study of sentinel headache in aneurysmal subarachnoid haemorrhage

Retrospective surveys of patients with subarachnoid haemorrhage suggest that minor episodes with sudden headache (warning leaks) may precede rupture of an aneurysm, and that early recognition and surgery might lead to improved outcome. We studied 148 patients with sudden and severe headache (possible sentinel headache) seen by 252 general practitioners in a 5-year period in the Netherlands. Subarachnoid haemorrhage was the cause in 37 patients (25%) (proven aneurysm in 21, negative angiogram in 6, no angiogram done in 6, sudden headache followed by death in 4). 103 patients had headache as the only symptom, 12 of whom proved to have subarachnoid haemorrhage (6 with a ruptured aneurysm). Previous bouts of sudden headache had occurred in only 2. Other serious neurological conditions were diagnosed in 18. In the remaining 93, no underlying cause of headache was found; follow-up over 1 year showed no subsequent subarachnoid haemorrhage or sudden death. In this cohort, acute, severe headache in general practice indicated a serious neurological disorder in 37% (95% CI 29-45%), and subarachnoid haemorrhage in 25% (18-32%). 12% (5-18%) of those with headache as the only symptom. The notion of warning leaks as a less serious variant of subarachnoid haemorrhage is not supported by this study. Early recognition of subarachnoid haemorrhage is important but will probably have only limited impact on the outcome in the general population.

Headaches from aneurysms

The clinical features and differential diagnosis of aneurysmal rupture of the cerebral vessels are reviewed with special emphasis on the headaches associated with this disorder.

Does a safe size-limit exist for unruptured intracranial aneurysms?

Of 1076 patients with intracranial ruptured aneurysms (RA) included in the Danish Aneurysm Study, 948 had the RA verified by angiography. Of these cases 908 RA had a maximum diameter less than 25 mm. 162 RA were < 5 mm, 474 and 272 were between 5-10 mm and 11-24 mm, respectively. The average diameter of the RA according to the day of angiography after the aneurysm rupture did not differ significantly within the first 10 days. In these circumstances, using this indirect method for estimation of aneurysm rupture according to the size, we also recommend that unruptured aneurysms with a size 10 mm or less should be seriously considered for operation.