Diffuse cerebral air embolism treated with hyperbaric oxygen: a case report

A 54-year-old woman presented for cardiac evaluation of atypical chest pain. Workup included coronary angiography and a left ventriculogram, during which air was inadvertently injected, resulting in the development of an acute right hemisphere syndrome. Right carotid angiography was immediately performed, yielding only a delayed diffuse venous phase without focal vessel cutoffs. Within 60 minutes, the patient underwent hyperbaric oxygen therapy for the suspected cerebral air emboli. After removal from the chamber for technical reasons, she had a generalized tonic-clonic seizure, and further hyperbaric oxygen therapy was withheld. Initial computed tomography imaging obtained approximately 8 hours after symptom onset showed signs of early right hemispheric edema. Subsequent magnetic resonance imaging studies were markedly abnormal and suggestive of diffuse bilateral but predominantly right-sided parietal lobe edema with mildly positive diffusion-weighted imaging. Follow-up magnetic resonance imaging at 6 months was normal, and the patient's neurological examination returned to normal.

CSF-ACE activity in probable CNS neurosarcoidosis

OBJECTIVE

To redefine the utility of CSF-ACE as a selective indicator of probable CNS neurosarcoidosis.

METHODS

The diagnosis of probable CNS neurosarcoidosis required: (a) biopsy evidence of systemic sarcoidosis, (b) cortical, brainstem, and/or spinal cord deficits, (c) enhancing lesions on brain and/or spinal cord MRI, and (d) exclusion of other etiologies which could account for the neurological deficits. Radioassay measurement of CSF-ACE activity was performed in 11 patients who met our criteria for probable CNS neurosarcoidosis and 207 control patients.

RESULTS

The M +/- SD for CSF-ACE activity was significantly higher (p < 0.05) for the 11 probable CNS neurosarcoidosis patients (9.5 +/- 6.9 nmol/mL/min) than for the control patients (2.9 +/- 2.7 nmol/mL/min). The optimal CSF-ACE activity discriminator value was 8 nmol/mL/min. At this value, the sensitivity and specificity of CSF-ACE activity was 55% and 94%, respectively.

CONCLUSIONS

CSF-ACE activity is a useful biochemical marker of probable CNS neurosarcoidosis when brain and/or spinal cord MRI show diffuse enhancing lesions.

High-dose cyclophosphamide without stem-cell rescue for refractory CIDP

Four patients with chronic inflammatory demyelinating polyneuropathy (CIDP) who were refractory to conventional treatment were treated with high-dose cyclophosphamide (200 mg/kg over 4 days). All improved in functional status and muscle strength. Nerve conduction studies improved in three of four. Other immunomodulatory medications have been discontinued. High-dose cyclophosphamide can be given safely to patients with CIDP and patients with disease persistence after standard therapy may have a response that lasts for over 3 years and results in long-term disease remission.

External ophthalmoplegia with severe progressive multiorgan involvement associated with the mtDNA A3243G mutation

BACKGROUND

Chronic progressive external ophthalmoplegia (CPEO) may be related to primary nuclear DNA or mitochondrial (mt)DNA mutations. The A3243G mtDNA point mutation most frequently causes mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, but also has been associated with other phenotypes including CPEO, migraine, seizure, diabetes, and sensorineural hearing loss.

CASE DESCRIPTION

We report a 38-year-old white man with seizures and progressive difficulties of infantile origin including CPEO, sensorineural hearing loss, cataracts, migraines, multiple endocrinopathy, myopathy, and cardiomyopathy. Moderate hearing loss in association with CPEO, diabetes mellitus, or migraines were noted in the proband's maternal grandmother, great aunt, mother, and three sisters, suggesting either an autosomal dominant or maternal inheritance. Detailed histological and biochemical analysis of the proband's biopsied muscle specimen revealed severe abnormalities compatible with a mitochondrial disease. MtDNA analysis excluded large-scale deletions, but revealed a heteroplasmic A to G transition at nt3243 in 56.4% and 27.4% of molecules in muscle and white blood cells, respectively.

CONCLUSION

We discuss possible causes of this intrafamilial heterogeneity of phenotypes associated with the A3243G mtDNA mutation.

Reflex sympathetic dystrophy

Reflex sympathetic dystrophy (RSD) is composed of five major features: pain, swelling, autonomic dysregulation, movement disorders, and atrophy and dystrophy. RSD is caused by an injury to a specific nerve or the C- and A-delta fibers that innervate the involved tissue. It is a progressive illness that spreads with time and may encompass the entire body. There is no psychological disposition to the problem, but all patients are severely depressed because of the constant pain, lack of sleep, and complete disruption of their lifestyle. The continuing pain is usually secondary to the process of central sensitization. The autonomic dysregulation has a major central nervous system component. Atrophy and dystrophy are partly due to loss of nutritive blood supply to the affected tissues. The movement disorder is partly due to deficiency of GABAergic mechanisms; the tremor is an exaggeration of the normal physiologic tremor. Treatment consists of decreasing the afferent pain, maintaining barrage from the underlying defect, and blocking the sympathetic component of the process. New developments include the use of neurotrophic factors to reverse the phenotypic changes that occur in the dorsal horn and the use of pharmacologic agents to block the activity-dependent NMDA channels that appear to be instrumental in maintaining central sensitization.

Diagnostic criteria used in studies of reflex sympathetic dystrophy

OBJECTIVE

Assessment of the diagnostic criteria of reflex sympathetic dystrophy (RSD) and evaluation of the impact of the introduction of the diagnostic criteria of complex regional pain syndrome (CRPS) on the international application of diagnostic criteria of RSD.

METHODS

Randomized controlled trials and clinical investigations, published between January 1980 and June 2000, were evaluated with regard to the applied diagnostic criteria of RSD.

RESULTS

One hundred seven studies were identified. Thirty-four of these studies were excluded because of inadequate reporting of diagnostic criteria. The 73 included studies were not homogeneous with regard to the diagnostic criteria because they applied many different aspects of sensory and autonomic features. Only 12% of the studies considered the presence of motor features, mostly vaguely described, as mandatory for the diagnosis RSD. Although 10 of the 23 studies published since the introduction of CRPS have applied this term, only 3 used the exact criteria without additions or other modifications.

CONCLUSION

Diagnostic criteria sets of RSD focus on many different aspects of sensory and autonomic features that generally are described vaguely. This has not changed since the introduction of the CPRS criteria. These findings question whether the current criteria adequately define RSD.

Neurologic complications of the Novacor left ventricular assist device

BACKGROUND

The left ventricular assist device (LVAD) is a bridging mechanism for patients with severe heart failure to remain viable until heart transplantation. The rate of cerebral embolism has been reported as high as 47% in some studies but the rate of other neurologic complications in patients with LVADs is not known.

METHODS

Retrospective chart review of all patients who had LVADs implanted at our hospital from September 1993 until September 1997. Complications from the time of implantation until heart transplantation or death and functional outcome were assessed.

RESULTS

Twenty-three patients had LVADs placed in the four-year period. Of 23 patients, 9 had neurologic complications after placement of the LVAD. These included four strokes, three seizures, and two cases of delirium. The 3 patients with seizures all died from multiorgan failure. All of the patients with strokes received a transplant. One patient with delirium died from multiorgan failure and another received a transplant. The most devastating medical complication was renal failure, which occurred in 7 patients and was associated with 100% mortality. All surviving patients with neurologic complications went on to transplant and good functional outcome.

CONCLUSIONS

Neurologic complications are common in patients with LVADs, occurring in 9 out of 23 patients in our series. Seizures are a poor prognostic indicator and were associated with 100% mortality. Strokes did not have a negative impact on outcome. Patients with delirium had a mixed outcome, which reflects the multifactorial nature of delirium. Further study needs to be done to limit the neurologic complications associated with LVADs and further improve outcomes.

Neuropathic central pain: epidemiology, etiology, and treatment options

BACKGROUND

Nociceptive pain is a major problem in clinical neurology. Peripheral nerve injury may change the physiology of the dorsal horn so that pain becomes progressively centralized.

OBJECTIVE

To review mechanisms underlying the plasticity of dorsal root ganglia and dorsal horn neurons that lead to central pain from a peripheral nerve injury.

RESULTS

Evidence is reviewed that points to molecular changes in nociceptive terminals, ectopic firing of afferent pain fibers at the level of the dorsal root ganglia, and physiologic changes of the N-methyl-D-aspartate receptor that cause chronic nociceptive pain.

CONCLUSIONS

Central sensitization is the physiologic manifestation of many severe peripherally induced pain states. It is maintained by nociceptive input and a physiologic change in the N-methyl-D-aspartate receptor. It consists of: (1) hypersensitivity at the site of injury; (2) mechanoallodynia; (3) thermal hyperalgesia; (4) hyperpathia; (5) extraterritoriality in the case of complex regional pain syndrome/reflex sympathetic dystrophy; and (6) associated neurogenic inflammation, autonomic dysregulation, and motor phenomena.

Patterns of spread in complex regional pain syndrome, type I (reflex sympathetic dystrophy)

There are reports that complex regional pain syndrome, type I (reflex sympathetic dystrophy; CRPS-I/RSD) can spread from the initial site of presentation, but there are no detailed descriptions of the pattern(s) of such spread. We describe a retrospective analysis of 27 CRPS-I/RSD patients who experienced a significant spread of pain. Three patterns of spread were identified. 'Contiguous spread (CS)' was noted in all 27 cases and was characterized by a gradual and significant enlargement of the area affected initially. 'Independent spread (IS)' was noted in 19 patients (70%) and was characterized by the appearance of CRPS-I in a location that was distant and non-contiguous with the initial site (e.g. CRPS-I/RSD appearing first in a foot, then in a hand). 'Mirror-image spread (MS)' was noted in four patients (15%) and was characterized by the appearance of symptoms on the opposite side in an area that closely matched in size and location the site of initial presentation. Only five patients (19%) suffered from CS alone; 70% also had IS, 11% also had MS, and one patient had all three kinds of spread. Our results suggest that CRPS-I/RSD spread may not be a unitary phenomenon. In some it may be due to a local spread of pathology (CS); in others it may be a consequence of a generalized susceptibility (IS). In the MS case, spread may be due to abnormal neural functioning spreading via commissural pathways. Alternatively, we discuss the possibility that all three kinds of spread may be due to aberrant CNS regulation of neurogenic inflammation.

Quantitative sensory studies in complex regional pain syndrome type 1/RSD

OBJECTIVE

Patients with complex regional pain syndrome type I (CRPSD1) may have thermal allodynia after application of a non-noxious thermal stimulus to the affected limb. We measured the warm, cold, heat-evoked pain threshold and the cold-evoked pain threshold in the affected area of 16 control patients and patients with complex regional pain syndrome type 1/RSD to test the hypothesis that allodynia results from an abnormality in sensory physiology.

SETTING

A contact thermode was used to apply a constant 1 degrees C/second increasing (warm and heat-evoked pain) or decreasing (cold and cold-evoked pain) thermal stimulus until the patient pressed the response button to show that a temperature change was felt by the patient. Student t test was used to compare thresholds in patients and control patients.

RESULTS

The cold-evoked pain threshold in patients with CRPSD1/RSD (p <0.001) was significantly decreased when compared with the thresholds in control patients (i.e., a smaller decrease in temperature was necessary to elicit cold-pain in patients with CRPSD1/RSD than in control patients). The heat-evoked pain threshold in patients with CRPS1/RSD was (p <0.05) decreased significantly when compared with thresholds in control patients. The warm- and cold-detection thresholds in patients with CRPS1/RSD were similar to the thresholds in control patients.

CONCLUSIONS

This study suggests that thermal allodynia in patients with CRPS1/RSD results from decreased cold-evoked and heat-evoked pain thresholds. The thermal pain thresholds are reset (decreased) so that non-noxious thermal stimuli are perceived to be pain (allodynia).

Embolic stroke secondary to an aortic arch tumor--a case report

An acute stroke from an aortic arch tumor is reported. These tumors are rare and have to be differentiated from atheromas. Aortic atheromas commonly present with embolic phenomena and occasionally as masses. Aortic tumors are more likely to produce obstructive phenomena, presenting as a coarctation or dissection. Magnetic resonance imaging with gadolinium can facilitate the diagnosis. A literature review of aortic masses and their diagnosis and treatment are presented.

Postinjury neuropathic pain syndromes

Pain is clearly one of the most daunting problems of modern medicine. Posttraumatic neuropathic pain syndromes are a major component of the clinical problem. Structural lesions affecting roots, nerves, the plexi, and central structures can be imaged noninvasively. The molecular biology of the intraneural cascades that cause sensitization of the central pain-projecting neurons of the dorsal horn and subsequent allodynia, hyperalgesia, and hyperpathia is a subject of intense inquiry. The role of the clinician in identifying and eliminating the source of the pain is crucial before the effects of excitotoxicity and central sensitization permanently alter the physiology of the central pain-projecting neurons and make treatment ineffectual.

Personality assessment of patients with complex regional pain syndrome type I

OBJECTIVE

There is controversy regarding the importance of psychological/psychiatric factors in the development of the Complex Regional Pain Syndrome (CRPS). Our objective was to determine whether CRPS type I patients were psychiatrically different from other chronic pain patients, with particular attention to personality pathology.

DESIGN

A standardized clinical assessment of all major psychiatric categories, including personality disorders, was performed on 25 CRPS type I patients and a control group of 25 patients with chronic low back pain from disc-related radiculopathy.

MEASURES

Both sections of the Structured Clinical Interview for the Diagnostic and Statistical Manual (3rd ed., rev.) and the visual analog scale.

RESULTS

Both groups were similar in terms of pain intensity and duration. Statistical analysis showed both groups to have a significant amount of major psychiatric comorbidity, in particular major depressive disorder, and a high incidence of personality disorders. Therefore, intense chronic pain was associated with significant psychiatric comorbidity in both groups and in similar proportions.

CONCLUSION

The high incidence of personality pathology in both groups may represent an exaggeration of maladaptive personality traits and coping styles as a result of a chronic, intense, state of pain.

Long-term outcome following sympathectomy for complex regional pain syndrome type 1 (RSD)

We performed a retrospective study of 29 patients with CRPS1 (RSD) who were initially examined between 1983 and 1993, and had either transthoracic (lower third of stellate ganglia to T3) or lumbar (L2-L4) sympathectomy. The patients were followed from 24 to 108 months after surgery. Patients with unsuccessful surgical outcomes had significantly longer duration of symptoms before surgery (median, 36 months) than those with successful outcomes (median, 16 months) by Wilcoxon rank sum test (chi2=8.69, df=1, P<0.01). All seven patients (100%) who had sympathectomy within 12 months of injury, nine of 13 patients (69.2%) who had sympathectomy within 24 months of injury, and only four of nine patients (44.4%) who had sympathectomy after 24 months of injury obtained permanent (greater than 24 months) symptom relief. Patient age, sex, occupation, site of injury, type of injury, presence of trophic changes, and duration of follow-up were not significantly related (P>0.05) to surgical outcome.

Intracerebral microdialysis study of glutamate reuptake in awake, behaving rats

The central nervous system has high-affinity uptake systems for the clearance of amino acid transmitters. These systems are found in both neurons and astrocytes. Previous studies have shown that the uptake of amino acid transmitters by astrocytes in culture can be modulated by adrenergic agents. The objectives of this study were to develop a methodology that evaluates the brain's reuptake capacity for glutamate in awake, behaving animals and to determine whether glutamate reuptake is under alpha-adrenergic regulation in the intact central nervous system. Male Sprague-Dawley rats weighing 250-450 g were used in this study. The extraction fraction of L-[3H]glutamate with [14C]mannitol as a reference was measured. The cortical extraction fraction of L-[3H]glutamate corrected for [14C]mannitol (EL-glu) reaches steady state rapidly and is both stable and repeatable. EL-glu is a measure of L-glutamate reuptake and not metabolism. EL-glu is decreased in a dose-dependent manner by the addition of the glutamate reuptake blocker D,L-threo-beta-hydroxyaspartic acid or unlabeled L- glutamate. In addition, EL-glu is increased in a dose-dependent manner by the alpha1-adrenergic agonist phenylephrine, and this increase is blocked by the alpha-adrenergic antagonist phentolamine.

Idiopathic acute transverse myelitis: MR imaging findings

PURPOSE

To analyze the magnetic resonance (MR) imaging findings in idiopathic acute transverse myelitis (IATM) in relation to pathologic findings and MR findings in Guillain-Barré syndrome and ischemia.

MATERIALS AND METHODS

The cases of 19 patients with IATM seen over a 4-year period were retrospectively reviewed. Clinical parameters and laboratory test findings were recorded for each patient independently of the MR findings.

RESULTS

Ten (53%) patients experienced upper respiratory infection or vaccination within 4 weeks of symptom onset. The majority (82%) of cases occurred between December and May each year. In seven of 12 patients who underwent electromyography and nerve conduction examinations, evidence of peripheral nerve injury was seen. On T2-weighted axial images, 13 of 18 lesions were depicted with holocord abnormal signal intensity, seven (39%) had gray matter involvement similar to that seen in spinal cord ischemia, and three (16%) had isolated white matter involvement. Enhancement patterns varied. In three (17%) of the 18 lesions, enhancement in the cauda equina was similar to that seen in Guillain-Barré syndrome.

CONCLUSION

IATM may be caused by a small vessel vasculopathy. MR findings in IATM also occasionally are similar to those described in Guillain-Barré syndrome and suggest a possible relationship.

Urological symptomatology in patients with reflex sympathetic dystrophy

PURPOSE

We determined the effect of reflex sympathetic dystrophy on lower urinary tract function.

MATERIALS AND METHODS

A total of 20 consecutive patients (16 women and 4 men) with neurologically verified reflex sympathetic dystrophy was referred for voiding symptoms, including urgency, frequency, incontinence and urinary retention. No patient had had voiding symptoms before the initial trauma that induced reflex sympathetic dystrophy. Evaluation included medical history, physical examination, video urodynamic testing and cystoscopy.

RESULTS

Mean patient age was 43.4 +/- 10.2 years (range 28 to 58) and mean duration of urological symptoms was 4.9 +/- 3.6 years (range 1 to 14). Urodynamic study demonstrated a mean cystometric bladder capacity of 417 +/- 182 ml. (range 120 to 700). The urodynamic diagnoses included detrusor hyperreflexia in 8 patients, detrusor areflexia in 8, sensory urgency in 3 and detrusor hyperreflexia with detrusor-external sphincter dyssynergia in 1. In 4 women genuine stress urinary incontinence was also documented urodynamically.

CONCLUSIONS

Reflex sympathetic dystrophy may have a profound effect on detrusor and sphincter function.