Kelly D. Flemming, Keith Josephs, and Eelco F. M. Wijdicks
Wouter I. Schievink, Eelco F. M. Wijdicks, and James D. Kuiper
Object. The etiology of spontaneous cervical artery dissection is poorly understood; however, it may involve genetic and environmental factors. The purpose of this study was to determine whether seasonality of spontaneous cervical artery dissection exists.
Methods. The seasonal pattern of spontaneous cervical artery dissection was analyzed in a group of 200 consecutive patients (104 females and 96 males with a mean age of 44.9 years) who were evaluated using the Rayleigh test during the period from 1970 to 1990. The majority of patients resided in the midwestern section of the United States, where large seasonal fluctuations in climate occur. A circannual periodicity was found in the frequency of spontaneous cervical artery dissections with a peak occurring in October (p < 0.02). The seasonal variation was substantial, with approximately 58% more patients suffering a cervical artery dissection during autumn than during other seasons.
Conclusions. A seasonal pattern of spontaneous cervical artery dissection exists with a peak occurring in October. The cause of the seasonality remains to be explained; however, weather- or infectious disease—related factors may provide etiological leads.
Peter J. Koehler and Eelco F. M. Wijdicks
The aim of this study was to investigate the development of ideas about the nature and mechanism of the fixed dilated pupil, paying particular attention to experimental conditions and clinical observations in the 19th century. Starting from Kocher's standard review in 1901, the authors studied German, English, and French texts for historical information. Medical and neurological textbooks from the 19th and 20th centuries were reviewed to investigate when and how this information percolated through neurological and neurosurgical practices. Cooper experimented with intracranial pressure (ICP) in a dog in the 1830s, but did not mention the pupils. He described dilated pupils in clinical cases without referring to the effect of light. Bright demonstrated to have some knowledge of the pupil sign (clinical observations). Realizing the unreliability of the pupil sign, Hutchinson in 1867–1868 tried to reason in which cases trepanation would be advisable. Von Leyden's 1866 animal experiments, in which he increased CSF volume by injecting protein solutions intracranially, was the first observation in which the association between fixed dilated pupils and increased ICP was established. Along with bradycardia and motor and respiratory effects, he noticed wide pupils were usually present in a comatose state. Asymmetrical dilation could not always be attributed to increased ICP, but to an oculomotor nerve lesion. Pagenstecher in 1871 extended knowledge by meticulously studying consecutive pupil phenomena with increasing pressure. In 1880, von Bergmann emphasized the significance of the ipsilateral dilation in experiments as well as in clinical cases. He distinguished the extent of pressure increase and its duration. Probably confusing irritation (epileptic head turning to the other side with pupil dilation) and lesion effects, he suggested a cortical area responsible for oculomotor phenomena, indicating what is now known as the frontal eye field. Naunyn and Schreiber (1881) understood the relationship between increased ICP with pupil dilation and decreased pulse frequency and blood pressure, warning not to decrease the latter. Concentrating on experimental traumatic effects, Duret (1878) investigated compression and commotion, in which he distinguished two phases, notably pupil constriction by bulbar lesions, due to CSF shock, followed by dilation from congestion and inflammation, due to blood around the oculomotor nerve. The key observation of a fixed dilated pupil as a sign of acute mass effect came gradually and after some localization stumbles. Following the period of extensive experimental research in ICP, the results of which were translated to clinical observations, the prognostic significance was gradually acknowledged by authors of neurological textbooks. It is well known that Cushing did similar experiments in Berne (1900–1901), and later suggested he would not have done so if he had studied the literature.
Eelco F. M. Wijdicks, Denise M. Heublein, and John C. Burnett JR.
Object. Natriuresis is a common systemic manifestation of aneurysmal subarachnoid hemorrhage (SAH). Natriuresis and its accompanying hypovolemia may be a major contributing factor in the pathophysiology of symptomatic cerebral vasospasm.
Methods. The authors studied 14 consecutive patients with aneurysmal SAH and compared levels of adrenomedullin (ADM), a novel endogenous natriuretic peptide that possesses additional profound vasodilatory properties, with the natriuretic peptide system by using radioimmunoassay. The mean ADM values on admission were 24.8 pg/ml, a twofold increase over control values, but no correlation was found with atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-natriuretic peptide (CNP) from the natriuretic peptide system. At Day 5 post-SAH, ADM levels were significantly elevated in patients with vasospasm documented angiographically or on transcranial Doppler studies as compared with those who suffered no vasospasm (mean 61.9 pg/ml compared with 15.3 pg/ml, p < 0.01).
Conclusions. The authors conclude that an elevation of ADM in plasma may indicate a physiological regulatory attempt to induce cerebral vasodilation. The regulation of ADM is uncoupled from ANP, BNP, and CNP.
Eelco F. M. Wijdicks, Wouter I. Schievink, and John C. Burnett Jr.
✓ The natriuretic peptide system consists of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). The system is implicated in the control of body fluid homeostasis, causes natriuresis and diuresis (ANP and BNP), and regulates vascular tone (CNP). A reciprocal relationship between ANP and endothelin (ET) has been suggested, and earlier studies have documented a possible role of ET in cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH).
The authors studied plasma ANP, BNP, CNP, and ET for 6 consecutive days in 13 patients with SAH by using radioimmunoassay. The median admission values for ANP were 31.5 pg/ml (range 16.8–323 pg/ml [normal 15 ± 7 pg/ml]); for BNP, 45.3 pg/ml (range 2.2–80.2 pg/ml [normal 12 ± 9 pg/ml]); for CNP, 7.7 pg/ml (range < 2–20 pg/ml [normal 5.2 ± 3 pg/ml]); and for ET, 11 pg/ml (range 6.5–25.1 pg/ml [normal 7.2 ± 4 pg/ml]). Additional increases (defined as > 100% increase on two consecutive measurements) were noted in ANP (11 patients), BNP (10 patients), and CNP (three patients), and resulted in a negative fluid balance in 10 of the 13 patients. The CNP increased in three of four patients with cerebral vasospasm and in one of nine patients without cerebral vasospasm (Fisher's exact test, p = 0.2). No major fluctuations in plasma ET were noted. In seven patients, the plasma ET level did not increase beyond 10 pg/ml during the days of measurement. In six patients, only an occasional sample showed an increase to a maximum of 25 pg/ml. Changes in BNP, ANP, and CNP were independent of each other.
The authors conclude that both plasma ANP and BNP increase after SAH and often result in a negative fluid balance. Plasma ANP and BNP seem differentially regulated in the presence of SAH but not by the level of the plasma ET. The possible role of CNP as a regulatory response to cerebral vasospasm needs further exploration.
Robert D. Henderson, Thanh G. Phan, David G. Piepgras, and Eelco F. M. Wijdicks
Object. Intracerebral hemorrhage (ICH) is an uncommon complication of carotid endarterectomy (CEA), and carries a high rate of mortality and morbidity. Traditionally, attention has been focused on the cerebral hyperperfusion syndrome (HPS) as the leading cause of ICH after CEA. Other mechanisms, such as a perioperative cerebral ischemic event, cerebral infarction, and use of postoperative anticoagulation therapy, may also be important.
Methods. The authors performed a retrospective case control study to identify factors leading to ICH after CEA. Records of CEAs performed over the past 10 years at the Mayo Clinic were searched for occurrences of ICH within 30 days of the procedure. The relationship of ICH to known cerebrovascular risk factors, perioperative electroencephalographic studies, and 133Xe cerebral blood flow (CBF) studies was compared with that in a control group. Hyperperfusion was defined as hypertension with symptoms of either severe headache, seizures, or confusion, or a doubling of intraoperative CBF values. The clinical history and imaging of ischemic events and the ICH were carefully reviewed to determine the possible underlying mechanism(s).
Twelve (0.4%) of 2747 patients who underwent CEAs suffered a postoperative ICH. A doubling of CBF values was found in five of eight cases in which CBF studies were performed, and occurred more commonly in the patients with ICH than in controls. Clinical symptoms of the HPS were less common (three cases). A perioperative cerebral ischemic event (four cases) and anticoagulation therapy (six cases) were other contributors to a subsequent ICH. Seven of the 12 patients with ICHs died and five achieved a moderate outcome.
Conclusions. An ICH following CEA is an unusual complication that occurs in the setting of hyperperfusion, perioperative cerebral ischemia, anticoagulation therapy, or multiple mechanisms. Identification of CBF doubling at surgery may assist in identifying patients at risk for ICH following CEA.
Jan van Gijn, Albert Hijdra, Eelco F. M. Wijdicks, Marinus Vermeulen, and Hans van Crevel
✓ Hydrocephalus, defined as a bicaudate index above the 95th percentile for age, was found in 34 (20%) of 174 prospectively studied patients with subarachnoid hemorrhage (SAH) who survived the first 24 hours and who underwent computerized tomography (CT) scanning within 72 hours. The occurrence of acute hydrocephalus was related to the presence of intraventricular blood, and not to the extent of cisternal hemorrhage. The level of consciousness was depressed in 30 of the 34 patients. Characteristic clinical features were present in 19 patients, including a gradual obtundation after the initial hemorrhage in 16 patients and small nonreactive pupils in nine patients (all with a Glasgow Coma Scale score of 7 or less). In the remaining 15 patients (44%), the diagnosis could be made only by CT scanning. After 1 month, 20 of the 34 patients had died: six from rebleeding (four after shunting), 11 from cerebral infarction (eight after an initial improvement), and three from other or mixed causes. Only one of nine patients in whom a shunt was placed survived, despite rapid improvement in all immediately after shunting. The mortality rate among patients with acute hydrocephalus was significantly higher than in those without, with the higher incidence caused by cerebral infarction (11 of 34 versus 12 of 140 cases, respectively; p < 0.001). Death from infarction could not be attributed to the extent of cisternal hemorrhage, the use of antifibrinolytic drugs, or failure to apply surgical drainage, but could often be explained by the development of hyponatremia, probably accompanied by hypovolemia.
Boby V. Maramattom, Jeffrey W. Britton, Gena R. Ghearing, and Eelco F. M. Wijdicks
Stefan A. Dupont, Giuseppe Lanzino, Eelco F. M. Wijdicks, and Alejandro A. Rabinstein
In this study, the authors' goal was to minimize false-negative results in the detection of ruptured cerebral aneurysms.
The authors retrospectively reviewed the clinical and radiological information in consecutive adult patients admitted with acute subarachnoid hemorrhage (SAH) to their hospital between January 1, 2002, and January 1, 2008. Patients were grouped based on the presence or absence of a ruptured aneurysm, which was detected by catheter angiography. Multivariate logistic regression analysis was used to identify factors predicting detection of aneurysmal rupture by angiography.
The authors identified 199 patients (121 women [61%]). A ruptured aneurysm was detected in 167 patients (84%). In multivariate analysis, loss of consciousness at the onset of SAH was a strong predictive factor associated with detection of a ruptured aneurysm on subsequent angiography (OR > 100, p = 0.0002). The positive predictive value of loss of consciousness at the onset of SAH for detection of a ruptured aneurysm was 100%.
Loss of consciousness at the onset of SAH is highly predictive of aneurysm rupture. A negative CT angiography study in these patients may be a false result, and a high-quality catheter angiography should be performed.
Case report and historical perspective
Boby V. Maramattom, Aaron A. Cohen-Gadol, Eelco F. M. Wijdicks, and David Kallmes
✓ The discovery of either a dermatomal cutaneous nevus or a spinal arteriovenous malformation (AVM) should raise the suspicion of Cobb syndrome. The Cobb syndrome is a neurocutaneous syndrome in which there are metameric cutaneous and spinal AVMs. The authors present the case of a patient with acute cervical myelopathy and subtle cutaneous hemangiomas in whom a cervical perimedullary fistula was discovered. They also acknowledge Harvey Cushing's contribution to the recognition of this syndrome.