Jon Brillman

Microemboli during coronary artery bypass grafting. Genesis and effect on outcome.

Cerebral dysfunction after coronary artery bypass operations represents some of the most serious and costly complications of cardiac surgery. We used transcranial Doppler ultrasonography to detect and quantify the number of microemboli in the right middle cerebral artery of patients undergoing elective first coronary bypass operations (n = 117) and second coronary bypass operations (n = 10). We hypothesized that total microemboli were related to clinical outcome. A 2 MHz transducer was positioned in front of the ear above the zygomatic arch and depth gated to 50 mm. Microemboli were recorded as perturbations of the blood flow velocity in the middle cerebral artery and aurally monitored. Each episode of microembolism was specified both by clock time and as a perfusion or surgical event. Forty-one patients (32%) completed neuropsychologic evaluation with a battery of tests for cognitive function. Anxiety states and traits were also assessed. The distribution of microembolism showed that there were three groups of patients: < 30 microemboli (n = 83); 30 to 59 (n = 24); and > 60 (n = 20). Seven of 10 patients with cerebral complications (stroke, coma, delirium, aberrant behavior) were in the > 60 microemboli group. Those with cerebral complications had 20.7 +/- 4.5 microemboli from perfusion and 57.4 +/- 15.6 from surgical events. The 13 patients in the > 60 microemboli group without central nervous system symptoms had 95.5 +/- 19.5 microemboli from perfusion and 36.0 +/- 6.9 from surgical events. Neuropsychologic scores were most often depressed for memory (73%), comprehension (49%), attention (46%), and constructional ability (44%). The greatest change was in total score in the > 60 microemboli group (-3.3 +/- 0.6) compared with -1.1 +/- 0.2 and -1.9 +/- 0.2 for the 30 to 59 and < 30 groups, respectively. The incidences of cardiac and pulmonary complications and mortality were different between those patients with < 60 microemboli versus those with > 60 microemboli. Cardiac and pulmonary complications and mortality percentages were 4.7%, 3.7%, and 0.9%, respectively, for the < 60 microemboli group and 20%, 20%, and 15%, respectively, for the > 60 microemboli group. We concluded that transcranial Doppler ultrasonography is a useful technique to quantify and detect the source of microemboli during coronary artery bypass operations and may be useful in assessing new operative strategies, the quality of the perfusion, and potentially as an indicator for pharmacologic therapy in the operating room in patients with high microemboli counts.

Stenting: a new approach to carotid dissection.

A patient with bilaterally occluded internal carotid arteries had a right hemispheric stroke followed by a left cerebral infarction, secondary to dissection from fibro–muscular dysplasia, seen also in the vertebral arteries. The occluded left carotid was reopened and stents placed, with apparent reestablishment of left hemispheric blood flow. The speech and other deficits resolved. Although its use is under investigation, percutaneous balloon angioplasty with stents may be an appropriate intervention when other measures do not prevent progressive ischemic events.

Increased middle cerebral artery flow velocity during the initial phase of cardiopulmonary bypass may cause neurological dysfunction.

One hundred twenty‐seven patients undergoing coronary artery bypass graft surgery were monitored by transcranial Doppler ultrasonography. Five patients had more than 50% increases in middle cerebral artery mean flow velocity during the initial phase (10–120 sec) of cardiopulmonary bypass. Four of these 5 developed neurological complications including stroke and encephalopathy. These results indicate that overperfusion of the basal cerebral arteries during cardiopulmonary bypass procedures may contribute to neurological dysfunction after the surgery

Dissections of the cervicocerebral arteries

We present four cases of cerebral ischemia secondary to dissections of cervicocerebal arteries. The majority of patients presented with transient ischemic attacks and strokes, although one patient presented with headache and focal seizure. In addition to history and physical examination, the diagnostic evaluation of these patients included computed tomography scan, carotid duplex studies, angiogram, and, in some cases, magnetic resonance imaging studies. Initially, the patients were anticoagulated with heparin and then with warfarin for a period of six to eight weeks. The emergency physician must consider such dissections in younger patients with sudden neurologic deficits and no or few risk factors for cerebrovascular disease. In our experience, these are not rare syndromes; with proper workup, prompt diagnosis, and therapy, the prognosis is usually excellent.

Transient Global Amnesia Associated with Bilateral Subdural Hematomas

An elderly man presenting with an episode of transient global amnesia was found to have bilateral subdural hematomas. The entity of transient global amnesia, its relationship to structural brain disease, and its possible pathogenesis are discussed.

Shunt-responsive dementia in sarcoid meningitis: role of magnetic resonance imaging and cisternography.

The authors report a patient with progressive cognitive and gait decline in association with sarcoid meningitis. The patient had evidence of active inflammation as determined by cerebrospinal fluid examination and was steroid dependent. Magnetic resonance imaging and radionucleotide cisternography were complementary in establishing the diagnosis of communicating hydrocephalus, and suggested that the patient would be shunt responsive.

Midbrain ptosis Caused by Periaqueductal Infarct Following Cardiac Catheterization: Early Detection With Diffusion‐Weighted Imaging

Isolated infarcts in the periaqueductal region are rare but have been reported after cardiac catheterization . The authors report a case of dorsal midbrain infarct which caused bilateral ptosis, partial upgaze paresis, and internuclear ophthalmoplegia imaged within eight hours with diffusionweighted imaging (DWI). The lesion was later confirmed on T2‐weighted images. Diffusion‐weighted imaging can rapidly confirm the diagnosis of this rare brainstem infarct.

Slowly Progressive En-plaque Intracranial Sarcoidosis: Magnetic Resonance Imaging and Biopsy Appearance

A patient with suspected multiple sclerosis was studied with serial brain magnetic resonance imaging (MRI) over a period of 3 years before undergoing brain biopsy of an intracranial lesion, which proved to be meningeal sarcoidosis. This is the first report of enhanced and unenhanced MRI study of biopsy‐proved intracranial meningeal sarcoidosis. Invasion of brain tissue seen on biopsy specimens could not be inferred from the MRI appearance.

Neurological Evaluation in the Elderly

Various expressions of neurological impairment usually have a direct relationship to advancing age. If one has the good fortune to defer systemic illness, there usually is, to a varying degree, an inexorable decline in coordination, motor function, and intellectual prowess with advancing years. Advanced dementia, parkinsonism, and disorders of praxis are easily recognizable by non-neurologists. More subtle declines in function, such as benign forgetfulness, minor alterations in tone and balance, and early parkinsonism often require the assistance of a neurologist for further definition (Kral, 1962). This chapter demonstrates how the standard neurologic examination may be applied to patients of advanced years and how it may assist the examiner in the differential diagnosis of neurological conditions common to the elderly (Wolfson & Katzman, 1983).

The Magnetic Resonance Image Appearance ofMycoplasma neumoniaeEncephalopathy

Although the pathogenesis is unknown, the neurological manifestations of Mycoplasma pneumoniae are protean. Direct nervous system invasion by the organism and an autoimmune demyelination have been implicated. The patient reported here developed M. pneumoniae encephalopathy wherein the clinical and imaging data documented the development and resolution of a central nervous system lesion consistent with inflammation. The images and clinical course suggest a delayed hypersensitivity or autoimmune process similar to that of acute disseminated encephalomyelitis.