Posterior reversible encephalopathy in the intensive care unit.

Posterior reversible encephalopathy syndrome (PRES) is increasingly diagnosed in the emergency department, and medical and surgical intensive care units. PRES is characterized by acute onset of neurologic symptoms in the setting of blood pressure fluctuations, eclampsia, autoimmune disease, transplantation, renal failure, or exposure to immunosuppressive or cytotoxic drugs, triggers known to admit patients to the intensive care unit (ICU). Although the exact pathophysiology remains unknown, there is growing consensus that PRES results from endothelial dysfunction. Because of the heterogeneous nature of the disorder, it is probable that different mechanisms of endothelial injury are etiologically important in different clinical situations. The presence of bilateral vasogenic edema on brain imaging, particularly in parieto-occipital regions, is of great diagnostic utility but PRES remains a clinical diagnosis. Although largely reversible, PRES can result in irreversible neurologic injury and even death. The range of clinical and radiographic manifestations of the syndrome is probably broader than previously thought, and it is imperative that clinicians become familiar with the full spectrum of the disorder, as prompt recognition and elimination of an inciting factor improve outcome. PRES may be the most frequent toxic-metabolic encephalopathy seen in the ICU.

Distinguishing clinical and radiological features of non-traumatic convexal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The full spectrum of causes of convexal subarachnoid hemorrhage (cSAH) requires further investigation. Therefore, our objective was to describe the spectrum of clinical and imaging features of patients with non-traumatic cSAH. METHODS: A retrospective observational study of consecutive patients with non-traumatic cSAH was performed at a tertiary referral center. The underlying cause of cSAH was characterized and clinical and imaging features that predict a specific etiology were identified. The frequency of future cSAH or intracerebral hemorrhage (ICH) was determined. RESULTS: In all, 88 patients [median age 64 years (range 25-85)] with non-traumatic cSAH were identified. The most common causes were reversible cerebral vasoconstriction syndrome (RCVS) (26, 29.5%), cerebral amyloid angiopathy (CAA) (23, 26.1%), indeterminate (14, 15.9%) and endocarditis (9, 10.2%). CAA patients commonly presented at an older age than RCVS patients (75 years versus 51 years, P < 0.0001). Thirteen patients (14.7%) had recurrent cSAH, and 12 patients (13.6%) had a subsequent ICH. However, the risk was high amongst those with CAA compared to those caused by RCVS, with recurrent cSAH in 39.1% and subsequent lobar ICH in 43.5% of CAA cases. CONCLUSIONS: Our study demonstrates the clinical diversity of cSAH. Older age, sensorimotor dysfunction and stereotyped spells suggest CAA as the underlying cause. Younger age and thunderclap headache predict RCVS. Yet, various other causes also need to be considered in the differential diagnosis.

Central pontine and extrapontine myelinolysis: a systematic review.

The purpose was to perform a systematic review of studies on central pontine and extrapontine myelinolysis [forms of osmotic demyelination syndrome (ODS)] and define the spectrum of causes, risk factors, clinical and radiological presentations, and functional outcomes of this disorder. A thorough search of the literature was conducted using multiple databases (PubMed, Ovid Medline and Google) and bibliographies of key articles to identify all case series of adult patients with ODS published from 1959 to January 2013. Only series with five or more cases published in English were considered. Of the 2602 articles identified, 38 case series were included comprising a total of 541 patients who fulfilled our inclusion criteria. The most common predisposing factor was hyponatremia (78%) and the most common presentation was encephalopathy (39%). Favorable recovery occurred in 51.9% of patients and death in 24.8%. Liver transplant patients with ODS had a combined rate of death and disability of 77.4%, compared with 44.7% in those without liver transplantation (P < 0.001). ODS is found to have a good recovery in more than half of cases and its mortality has decreased with each passing decade. Favorable prognosis is possible in patients of ODS, even with severe neurological presentation. Further research is required to confirm the differences found in liver transplant recipients.

Early basal ganglia hyperperfusion on CT perfusion in acute ischemic stroke: a marker of irreversible damage?

BACKGROUND AND PURPOSE: CT perfusion scans are often used in acute stroke evaluations. We aimed to assess the outcome of areas of basal ganglia hyperperfusion on CTP in patients with acute ischemic stroke. MATERIALS AND METHODS: We retrospectively reviewed the medical records and brain imaging of 139 patients presenting with acute stroke who underwent CTP for consideration of endovascular recanalization. Hyperperfusion was assessed qualitatively and defined as a matched region of increased cerebral blood flow and cerebral blood volume. CTA was used to locate arterial occlusion. Follow-up imaging was used to determine whether regions of hyperperfusion at baseline became infarcted or developed hemorrhage. Angiographic imaging was assessed to determine the presence or absence of early venous opacification. RESULTS: Six patients (4.3%) demonstrated hyperperfusion in the basal ganglia of the affected side (4 in the lenticular nucleus and 2 in the caudate). In all cases, the area of hyperperfusion ultimately proved to be infarcted. All patients had received intravenous thrombolysis before the CTP. CTA at the time of CTP showed middle or distal M1 occlusion but patency of the proximal M1 and A1 segments. Intracranial hemorrhage was noted in 2 of these 6 patients at follow-up. CONCLUSIONS: Acute basal ganglia hyperperfusion in patients with stroke may indicate nonviable parenchyma and risk of hemorrhagic conversion.

Prognostication of neurologic outcome in cardiac arrest patients after mild therapeutic hypothermia: a meta-analysis of the current literature.

PURPOSE: To assess the sensitivity and false positive rate (FPR) of neurological examination and somatosensory evoked potentials (SSEPs) to predict poor outcome in adult patients treated with therapeutic hypothermia after cardiopulmonary resuscitation (CPR). METHODS: MEDLINE and EMBASE were searched for cohort studies describing the association of clinical neurological examination or SSEPs after return of spontaneous circulation with neurological outcome. Poor outcome was defined as severe disability, vegetative state and death. Sensitivity and FPR were determined. RESULTS: A total of 1,153 patients from ten studies were included. The FPR of a bilaterally absent cortical N20 response of the SSEP could be calculated from nine studies including 492 patients. The SSEP had an FPR of 0.007 (confidence interval, CI, 0.001-0.047) to predict poor outcome. The Glasgow coma score (GCS) motor response was assessed in 811 patients from nine studies. A GCS motor score of 1-2 at 72 h had a high FPR of 0.21 (CI 0.08-0.43). Corneal reflex and pupillary reactivity at 72 h after the arrest were available in 429 and 566 patients, respectively. Bilaterally absent corneal reflexes had an FPR of 0.02 (CI 0.002-0.13). Bilaterally absent pupillary reflexes had an FPR of 0.004 (CI 0.001-0.03). CONCLUSIONS: At 72 h after the arrest the motor response to painful stimuli and the corneal reflexes are not a reliable tool for the early prediction of poor outcome in patients treated with hypothermia. The reliability of the pupillary response to light and the SSEP is comparable to that in patients not treated with hypothermia.

What is meant by "TICI"?

BACKGROUND: In 2003, Higashida et al proposed the Thrombolysis In Cerebral Infarction scale to evaluate angiographic intracranial flow. Our aim is to review how subsequently published studies define TICI. MATERIALS AND METHODS: We used the ISI Web of Knowledge and SciVerse Scopus databases to search for "TICI" and "thrombolysis in cerebral infarction" and for articles that cited the original TICI paper from January 2004 through May 2012. Articles were categorized according to their definition of the TICI categories, typically grades 0-4, with grade 2 (partial reperfusion) subdivided into 2a and 2b, and rate of contrast entry to the perfused area. In addition, we catalogued the type of redefinitions of TICI subcategory 2 and additions of new categories. RESULTS: Of 236 articles screened, 74 were included. Eight (11%) explicitly followed the TICI scale as originally defined. Thirty-seven (50%) cited Higashida but did not define their scale. Fifteen (21%) used and explained modified scales. Thirteen (18%) used the term TICI, but did not define the scale and did not cite Higashida. Eighteen (24%) specified a 2a subcategory. Nine defined grade 2a as <67% filling, 6 defined it as <50%, and 3 did not offer a percentage. Two studies added a 2c subcategory. Fifty-two (70%) used a cutoff level to define "successful reperfusion." Of these, 65% used TICI ≥2, 33% used TICI ≥2b, and 2% used TICI = 3. CONCLUSIONS: There is substantial variability in the definition and/or application of the TICI scale in the literature. This variability could considerably impact our understanding of results of revascularization studies.

Susac syndrome: clinical characteristics and treatment in 29 new cases.

BACKGROUND AND PURPOSE: There are few clinical studies on the attempted treatments and outcomes in patients with Susac syndrome (SS) (retinocochleocerebral vasculopathy). METHODS: A retrospective review was performed of all patients presenting with SS at the Mayo Clinic in Rochester, Minnesota, USA (1 January 1998-1 October 2011). RESULTS: There were 29 cases of SS (24 women, mean age at presentation, 35 years; range, 19-65; full triad of brain, eye, and ear involvement, n = 16; mean follow-up time, 29 months). Thirty CSF analyses were performed in 27 cases (mean protein 130 mg/dl, range 35-268; mean cell count 14, range 1-86). MRI of the brain showed corpus callosal involvement (79%), T2-weighted hyperintensities (93%), and gadolinium enhancement (50%). Average lowest modified Rankin Scale score was 2.5 (median 2, range 0-5). Most patients (93%) received immunosuppressive treatment, with a mean time to treatment of 2 months following symptomatic onset. Treatments included intravenous methylprednisolone or dexamethasone (n = 23), oral corticosteroids (n = 24), plasma exchange (PLEX) (n = 9), intravenous immunoglobulin (IVIg) (n = 15), cyclophosphamide (n = 6), mycophenolate mofetil (n = 5), azathioprine (n = 2), and rituximab (n = 1). Most patients also received an antiplatelet agent (n = 21). Improvement or stabilization was noted in eight of 11 cases treated with IVIg in the acute period (three experienced at least partial deterioration) and eight of nine cases of PLEX treatment (one lost to follow up). CONCLUSIONS: Susac syndrome may be severe, disabling, and protracted in some patients. PLEX may be an adjunct or alternative therapy for patients who do not experience symptomatic improvement following steroid treatment.

Wolf in sheep's clothing: acute chloroma disguised as a subdural hematoma.

BACKGROUND: Subdural hematomas are not infrequent among patients with hematologic disorders as they are prone to thrombocytopenia from their disease and chemotherapy. However, rarely these patients can also have leukemic involvement of the subdural space. METHODS: Case Report with CT scan and intraoperative photographs. RESULTS: A 45-year-old woman with acute myeloid leukemia presented with progressive headache, somnolence, and hemiparesis. She was noted to be thrombocytopenic. CT scan revealed a heterodense extra-axial lesion consistent with an acute to subacute subdural hematoma. There was no antecedent trauma. After platelet transfusion, she was taken for burr hole evacuation and an opalescent pearly white mass was encountered. Pathology revealed myeloid sarcoma. CONCLUSIONS: Myeloid sarcoma can mimic subdural hematoma both clinically and radiologically. It should be considered when a patient with a prior leukemia and no antecedent trauma presents with an extra-axial lesion.