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Biomedical subjects

E F Wijdicks

Publications and source records attributed to E F Wijdicks.

At least 37 records · Page 2Linked to original sources

Mechanisms of intracerebral hemorrhage after carotid endarterectomy.

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.

Aged↗

MR imaging in comatose survivors of cardiac resuscitation.

BACKGROUND AND PURPOSE: The prognosis of comatose survivors is determined by clinical examination. Early laboratory indicators of poor prognosis (such as evoked potentials) have low sensitivity. The role of MR imaging as a confirmatory study was investigated. METHODS: We studied fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted (DW) imaging in 10 patients comatose after cardiac arrest. RESULTS: None of the 10 comatose patients had myoclonus status epilepticus or fixed, dilated pupils on neurologic examination, and none had abnormal somatosensory-evoked potentials. Eight patients showed diffuse signal abnormalities, predominantly in the cerebellum (n = 5), the thalamus (n = 8), the frontal and parietal cortices (n = 8), and the hippocampus (n = 9). One patient showed normal MR imaging results, and one patient had abnormalities in the thalamus and cerebellum and minimal abnormality on DW images; both later awakened. None of the patients with abnormal cortical structures on FLAIR MR images recovered beyond a severely disabled state. CONCLUSION: MR imaging in comatose survivors may parallel the pathologic findings in severe anoxic-ischemic injury, and extensive abnormalities may indicate little to no prospects for recovery. If confirmed, MR imaging may have a role as a prognosticating test in anoxic-ischemic coma.

Adult↗

Complications during apnea testing in the determination of brain death: predisposing factors.

Apnea testing in brain death determination may result in cardiovascular complications. Hypotension occurred in 24% and cardiac arrhythmias occurred in <1% of the 145 apneic oxygenation procedures. Complications were noted in only 15% of apnea tests performed without any predisposing factors. Significantly more complications (39%) were observed in apnea tests with inadequate precautions, particularly in apnea tests without adequate preoxygenation (50%).

Adult↗

Long-term outcome in patients with Guillain-Barré syndrome requiring mechanical ventilation.

OBJECTIVE: To analyze long-term recovery and predictors of outcome in patients with Guillain-Barré syndrome (GBS) requiring mechanical ventilation. METHODS: The clinical and electrophysiologic data of 114 patients with GBS admitted to the intensive care unit between 1976 and 1996 (60 mechanically ventilated, 54 nonventilated) were reviewed. Functional disability and predictors of outcome were determined at 1 year and at maximal recovery using the Hughes scale. Good outcome was defined as ability to ambulate without assistance; poor outcome was defined as inability to ambulate independently. RESULTS: Mechanical ventilation was required in 81% of patients with a poor outcome. Mortality was 20% in patients ventilated for GBS. However, ventilated patients who survived did well, with 79% eventually regaining independent ambulation. Nineteen percent of patients improved at least one functional grade beyond 1 year. Univariate predictors of poor maximal recovery in ventilated GBS patients were increased age (p < 0.001)), upper limb paralysis (p = 0.004), duration of ventilation (p = 0.006), and delay of more than 2 days to transfer to a tertiary center (p < 0.001). However, only age (OR 1.99, p = 0.004) and delayed transfer (OR 19.8, p = 0.002) were independently predictive of poor outcome on multivariate analysis. CONCLUSION: Mechanically ventilated patients constitute the majority of GBS patients with a poor outcome, and mortality remains substantial in this subgroup (20%). Although recovery from severe GBS may be prolonged, most survivors regain independent ambulation.

Adolescent↗

Safety of discontinuation of anticoagulation in patients with intracranial hemorrhage at high thromboembolic risk.

BACKGROUND: Limited data are available to guide the management of anticoagulation in patients with intracranial hemorrhage (ICH) at high thromboembolic risk. OBJECTIVE: To review the management of anticoagulation in patients with ICH at high thromboembolic risk. PATIENTS AND METHODS: We reviewed the management of anticoagulation in 141 patients who have a high risk of ischemic stroke and have ICH while taking warfarin. The 30-day risk of ischemic stroke while not taking anticoagulation treatment was determined using Kaplan-Meier survival estimates. RESULTS: The indications for anticoagulation were a prosthetic heart valve (52 patients [group 1]), atrial fibrillation and cardioembolic stroke (53 patients [group 2]), and a recurrent transient ischemic attack or an ischemic stroke (36 patients [group 3]). A prior ischemic stroke occurred in 14 (27%) of group 1 patients and in 23 (43%) of group 2 patients. Death occurred in 43% of the 141 patients. The median time not taking warfarin in this cohort was 10 days. Three patients had an ischemic stroke within 30 days of warfarin therapy discontinuation. Using Kaplan-Meier survival estimates, the probability of having an ischemic stroke at 30 days following warfarin therapy cessation in groups 1, 2, and 3 was 2.9% (95% confidence interval, 0%-8.0%), 2.6% (95% confidence interval, 0%-7.6%), and 4.8% (95% confidence interval, 0%-13.6%), respectively. In the 35 patients who had warfarin therapy restarted, none had recurrence of ICH during the same hospitalization. CONCLUSIONS: Discontinuation of warfarin therapy for 1 to 2 weeks has a comparatively low probability of embolic events in patients at high embolic risk. This should be taken into consideration when deciding whether to continue or discontinue anticoagulation in these patients at high embolic risk. Early recurrence of ICH is exceedingly uncommon.

Adult↗

Post-intubation pulmonary function test in Guillain-Barré syndrome.

The value of daily postintubation respiratory function tests in predicting duration of ventilation in 37 mechanically ventilated patients with Guillain-Barré syndrome (GBS) was studied. Patients ventilated for less than 3 weeks were compared with those ventilated more than 3 weeks. Daily vital capacity and maximal inspiratory and expiratory pressures were summed to an integrated pulmonary function (PF) score. We calculated the PF ratio, which represents the PF score at day 12 after intubation divided by the PF score on the day of intubation. The PF ratio was greater than 1 in all 10 patients ventilated less than 3 weeks and was less than 1 in 19 of 27 patients ventilated for longer (P = 0.0001, Fisher exact test). The sensitivity of a PF ratio less than 1 for predicting duration of ventilation greater than 3 weeks was 70%; the specificity and positive predictive value were 100%. This study thus suggests that serial postintubation respiratory tests can provide a measure of respiratory status in patients with GBS. These parameters may help predict duration of ventilation and need for tracheostomy. If, at day 12, the PF ratio is less than 1, it is highly unlikely that patients will be weaned within 3 weeks, and tracheostomy should be performed. If the ratio is greater than 1, tracheostomy should be deferred, because a substantial proportion of these patients may be successfully weaned from the ventilator within 3 weeks.

Guillain-Barre Syndrome↗

Chronic subdural hematoma in autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) has been associated with an increased incidence of aneurysmal subarachnoid hemorrhage and intracerebral hematomas. We describe five patients with chronic subdural hematomas, a previously unrecognized complication of ADPKD. In four of the five cases, no trigger was apparent. Clinical presentation was subtle, with mild hemiparesis, headache, or both in four patients and transient neurological deficits mimicking transient ischemic attacks in one patient. In three of the five patients, a retrocerebellar arachnoid cyst was found, suggesting a plausible causal relation between the intracranial arachnoid cysts and the subdural hematomas. In one patient, subdural hematoma was in close proximity to the frontally located arachnoid cyst.

Aged↗

Predictors of poor outcome in patients with a spontaneous cerebellar hematoma.

BACKGROUND AND PURPOSE: The authors studied the clinical and neuroimaging features of cerebellar hematomas to predict poor outcome using comprehensive statistical models. METHODS: We retrospectively reviewed clinical and neuroimaging features in 94 patients with spontaneous cerebellar hematomas to identify predictive features for a poor neurologic outcome, defined as death or dismissal to long-term care facility. Data were analyzed using chi square and Fisher's exact test with calculation of odd's ratios together with 95% confidence intervals. RESULTS: Clinical and neuroradiologic predictors for a poor outcome at p < 0.05 were admission systolic blood pressure > 200 mm Hg, hematoma size > 3 cm, visible brain stem distortion, and acute hydrocephalus. Presenting findings predicting subsequent death at p < 0.05 were abnormal corneal and oculocephalic responses, Glasgow coma sum score less than 8, motor response less than localization to pain, acute hydrocephalus and intraventricular hemorrhage. CONCLUSION: A tree-based analysis model using binary recursive partitioning showed that cornea reflex, hydrocephalus, doll's eyes, age, and size were the most important discriminating factors. Absent corneal reflexes on admission highly predicts poor outcome (86 percent, confidence limits 67-96 percent). When a cornea reflex is present, acute hydrocephalus predicts poor outcome but only when doll's eyes are additionally absent.

Adult↗

Downbeat nystagmus associated with intravenous patient-controlled administration of morphine.

IMPLICATIONS: This case documents a patient who developed dizziness with downbeating nystagmus while receiving a relatively large dose of IV patient-controlled analgesia morphine. Although there have been case reports of epidural morphine with these symptoms and signs, this has not been previously documented with IV or patient-controlled analgesia morphine.

Analgesia, Epidural↗

False subarachnoid hemorrhage in anoxic encephalopathy with brain swelling.

The authors present two comatose patients with brain swelling from anoxic encephalopathy. Nonenhanced computed tomography (CT) images showed increased density on the falx, on the tentorium, and in the basal cisterns, all of which falsely suggested subarachnoid hemorrhage. Autopsy in both patients failed to show subarachnoid hemorrhage. In rare circumstances, anoxic encephalopathy can mimic subarachnoid hemorrhage on nonenhanced CT.

Aged↗