Regression Of Neurological Deficit Research Articles

Lesion of the craniovertebral junction in ankylosing spondylitis: rare clinical observations

Two cases of surgical treatment for lesions of the craniovertebral junction in patients with ankylosing spondylitis accompanied by severe neurological symptoms are described. Patients underwent one-step combined interventions. The first stage included occipitospondylodesis using screw instrumentation, and the second – transoral removal of the C2 odontoid process. Surgical treatment resulted in elimination of the spinal cord compression, regression of neurological deficit existed in patients before surgery, and achievement of stable fixation in the intervention area.

Effect of mexidol on the efficiency of intravenous thrombolytic therapy for ischemic stroke during the therapeutic window

Objective: to evaluate the effect of intravenous mexidol on the efficiency of intravenous thrombolytic therapy (TLT) during the therapeutic window. Patients and methods. The retrospective study enrolled 123 patients with ischemic stroke (IS) who had undergone intravenous TLT in the vascular centers of the Republic of Tatarstan. The National Institutes of Health Stroke Scale (NIHSS) was used to assess the time course of changes in their neurological status. According to the baseline severity of a neurological deficit, all the patients were divided into three subgroups: 1) mild IS (<8 NIHSS scores at admission); 2) moderate IS (>8 scores); and 3) severe IS (<16 scores). All the patients underwent X-ray computed tomography at admission, at 24 hours after TLT, and in case of worsening of their health status. Results. The prehospital use of mexidol followed by TLT in patients with IS had a positive effect on the regression of neurological deficit regardless of the severity of the disease. There were significant differences in the degree of regression of neurological deficit according to NIHSS at 24 hours and 10 days after hospital admission in patients with severe IS, who received intravenous mexidol at the prehospital stage and who did not take this drug before TLT. The pre-TLT use of mexidol contributed to higher regression of neurological deficit. There was a lower frequency of hemorrhagic transformations in the patients who used mexidol at the prehospital stage versus those who did not. Conclusion. The findings demonstrate the positive effect of mexidol on the efficiency and safety of TLT in patients with IS.

Pharmacological neuroprotection for intracerebral hemorrhages in patients with polyvascular disease

To evaluate the efficacy of pharmacological neuroprotection with protein, peptide and metabolic drugs as a part of basic intensive therapy for intracerebral hemorrhages in patients with polyvascular disease (PolyVD). Twenty-eight male patients with PolyVD referred to surgical treatment of intracerebral hemorrhages, who were on mechanical ventilation and received basic intensive care, were included in a single center prospective observational study. All patients were assigned either to routine daily i/v infusions of 10 ml cytoflavin in 0.9% sodium chloride solution for 10 days (n=12) or 0,2 mg daily of cellex subcutaneously (n=16). Central hemodynamics, intracranial pressure, and continuous indicators of the linear velocity of blood circulation were assessed. All patients underwent SOFA scoring. The markers of brain damage, including protein S-100-β (ng/l), antioxidant enzyme activity of superoxide dismutase (SOD) U/gr/Hb), glutathione peroxidase (U/gr/Hb) in the systemic circulation and jugular vein on the lesion side were determined. The length of stay in the intensive care unit and the number of nights were calculated. Mortality was assessed in both groups. Intracranial hypertension in both groups tended to subnormal parameters by 3-5 days. Vasospasm was reduced more rapidly (by the 3rd day) in the cytoflavin group compared to the cellex group (174 [152; 189] vs. 205 [182; 219], respectively). The latter demonstrated the less extent of cerebral damage according to S100 protein concentration. A comparative analysis showed that the antioxidant activity was significantly higher in the cytoflavin group. The cellex group demonstrated a pronounced trend towards the regression of neurological deficit on the NIHSS (p=0,025). The number of fatal outcomes and nights spent in the ICU were similar in both groups. The in-hospital stay was insignificantly shorter in the cellex group. It is recommended to add both antioxidant and neuropeptide pharmacological neuroprotectors in the routine intensive therapy for treating intracerebral hematomas in patients with PolyVD after surgical management.

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Background Surgical treatment is essential for patients with tuberculous spondylitis, abscess and compression of the spinal cord. Conservative treatment is practical for patients with tuberculous osteitis uncomplicated with compression of the spinal cord. Objective Make a comparative analysis of surgical treatment produced for pre-spondylitis and post-spondylitis patients with spine tuberculosis. Material and methods Surgical treatment was performed for 17 (28.8 %) patients with tuberculous osteitis and 42 (71.2 %) patients with progressing spondylitis. Debriding resection of tuberculous focus, decompression of the spinal cord, abscess drainage were followed by anterior spine fusion with mesh cages or porous constructs of memory metal nitinol, posterior spondylodesis with self-locking shape memory clamps or transpedicular system. Results Static and dynamic spine function, ability to work were restored in 16 (94.8 %) patients with tuberculous osteitis and 29 (69.1 %) patients with progressing spondylitis. Complications developed in 30.9 % of the patients with progressing spondylitis. Conclusions Application of combined spondylodesis allowed for restoration of static and dynamic function of the spine in 17 cases at 6-month follow-up. Early ambulation of patients with tuberculous osteitis and spondylitis was shown to provide regression of neurological deficit after stabilization of anterior and posterior supporting vertebral column. Surgical treatment combined with chemical therapy at early stages of spine tuberculosis appeared to prevent infection and neurological complications, and considerably reduce rehabilitation period

Результати лікування хворих із супратенторіальними пухлинами мозку з інсультоподібним перебігом у ранній післяопераційний період

Objective – to study early results of surgical treatment in 176 patients with supratentorial tumors (ST) with a stroke-like course. Materials and methods. The results of surgical treatment of 176 patients with stroke-like tumors were studied. They were treated at the urgent neurosurgery clinic of the Kyiv Emergency Hospital during the period from 2008 to 2015. The age of the patients was 20-70 years, the average age was (53.7 ± 13.4) years. There were 104 (59.1 %) men, 72 (40.9 %) women. Intracerebral tumors were diagnosed in 156 (88.6 %) cases, metastasis was observed in 35 (19.9%), 20 (11.4 %) patients have extracranial tumors Patients were divided into two groups depending on cerebrovascular accident: the group I – 103 patients had hemorrhagic type of cerebrovascular accident, the group II – 73 patients had ischemic type of cerebrovascular accident. In early postoperative period, CT and/or MRI was performed in all cases to detect postoperative complications and evaluate the radicality of surgical resection. An ophthalmologic review before and after surgery was performed. Results. Total resection was achieved in 68 (38.6 %) patients, near total – in 82 (46.6 %), subtotal – in 26 (14.8 %). All 176 patients had less than 70 points of Karnovsky scale before surgery, after treatment the number of this patients decreased to 36 (20.5 %) patients. Improvement of quality life was noted in regression of neurological deficits, restoration of functional disorders, high degree of social adaptation. Conclusions. The main criteria of successful surgical treatment of tumors with stroke-like course. is the survival of patients with radical surgical resection and satisfactory quality of life in the postoperative period. Factors that influence the removal of the tumors with stroke-like course are size of the lesion, its localization, and the histological characteristics of the tumors. Therapeutic tactics in patients with tumors with stroke-like course should be based on an individual approach. Adequate surgical removal of the tumors and hematomas evacuation improve the quality of life in most patients (79.5 %).

Топографічна анатомія та оперативна хірургія менінгіом та артеріальних аневризм навколоселярної локалізації

Objective – optimisation of surgical treatment of meningiomas (M) and arterial aneurysms (AA) of around sellar localization (ASL), according to the analysis of individual topographic and anatomical peculiarities. Materials and methods. The results of diagnostics and surgical treatment of 383 patients: 137 (35.8 %) with MASL (97 (70.8 %) women and 40 (29.2 %) men, the average age – 51.8 years) and 246 (64.2 %) with AA ASL (138 (56.1 %) women and 108 (43.9 %) men, the average age – 52.0 years) have been analyzed. All patients were operated at the SI Romodanov Neurosurgery Institute NAMS of Ukraine during the period from 01.01.2010 to 31.11.2016. Results. AA ASL proceeded from various segments of the internal carotid artery – 98 (39.8 %) cases, the anterior cerebral-anterior connective artery complex – 145 (59.0 %), bifurcation of the main arteria – 3 (1.2 %). Complex AA ASL was recorded in 52 (21.1 %) observations. Approaches to AA ASL: pterional – in 202 (82.1 %) cases, orbito-zygomatic – in 4 (1.6 %), pterional with anterior clinoidectomy – in 32 (13.0 %), subtemporal – in 8 (3.3 %). The following surgical approaches were used to remove MASL in patients: subfrontal – in 28 (20.4 %) observations, pterional – in 71 (51.9 %), frontoorbitozygomatic and its variants – in 38 (27.7 %). Total removal was achieved in 57 (41.6 %) patients, subtotal – in 22 (16.1 %), partial – in 58 (42.3 %). Improvement was observed in 38 cases and the preservation of the function of the optic nerves at the preoperative level was achieved in 78 cases. The achieved improvement in patients’ quality of life, in general, was characterized by a regression of neurological deficits, restoration of functional disorders and a high degree of social adaptation. Conclusions. The choice of craniotomy to AA ASL was dependent on localization and geometric parameters of AA relatively to the bone structures of the skull base, the volume and location of intracranial hemorrhage, the planned microsurgical corridor, the choice of an approach in MASL – relatively to topographic anatomy peculiarities of tumors, their sizes and surrounding anatomical structures. The choice of operative access for meningioma of ASL was due to the topographic and anatomical features of the tumors, their size, the relationship with the surrounding anatomical structures.

Результати хірургічного лікування менінгіом параселярної локалізації

Objective – to analyse of early surgical treatment results in patients with parasellar meningiomas. Materials and methods. It was presented early surgical treatment results in 137 patients with parasellar meningiomas, 40 (29.9 %) patients was men, 97 (70.8 %) – women. Average age was (51.8 ± 0.9) year. The selection criteria were meningiomas of tuberculum sellae, small wing and anterior clinoid process, medial part of the great wing of the sphenoid bone and lateral wall of the cavernous sinus. The approach was chosen by size of tumor, its localization and relations with neural structures. Results. Immediate surgical results in this series were satisfactory. Total removal was reached in 57 (41.6 %) patients, subtotal – in 77 (56.2 %), partial – in 3 (2.2 %). The improvement of visual nerve function was achieved in 38 (27.7 %) patients. Life quality improvement was achieved by regression of neurological deficit, good visual outcome and high-grade social adaptation. Conclusions. Combined frontotemporoorbitozigomatic approach is up-to-date in surgery of parasellar meningiomas. It allows appropriate total removal of parasellar meningiomas without severe brain retraction.

Experience of Using Amantadine Sulfate (PK-Merz) in Patients with Ischemic Stroke

The article presents the results of combination treatment of patients with acute ischemic stroke (the NIH Stroke Scale – 12.04±0.57). The efficacy of conventional therapy (the control group) was compared with treatment regimen using amantadine sulfate (PK-Merz) (the main group). In patients undergoing combination treatment lost functions were restored quite promptly and 2 months after the observation their functional state was satisfactory (the NIH Stroke Scale: the main group – 2.49±0.78, the control group – 5.53±0.69, p=0.009); moreover, the subscale “language” differed significantly from that in patients receiving basic therapy only (р<0.05). Due to the blockade of NMDA receptors, which contributes to the reduction in the intensity of the “excitotoxicity cascade” preserving the penumbral area as well as due to the increase in dopamine concentration both by increasing the release and blocking the re-uptake in presynaptic nerve cells, the use of amantadine sulfate is a pathogenetically justified means of cerebroprotection in the acute phase of ischemic stroke. The use of PK-Merz is proven to contribute to rapid recovery of consciousness, significant regression of neurological deficit resulting in disability reduction.

Эффективность митоксантрона у больных с прогредиентными типами течения рассеянного склероза

Изучена эффективность, безопасность и переносимость митоксантрона у 67 пациентов с прогредиентными типами течения (ПТТ) рассеянного склероза (РС).Проведен анализ клинико-радиологических данных у 19 больных с первично-прогредиентным (ППТ) и у 48 больных со вторично-прогредиентным течением (ВПТ) РС, получавших цитостатик II ряда — митоксантрон. Оценка клинической и радиологической активности заболевания по результатам лечения проводилась непосредственно после курса приема митоксантрона и ежегодно в течение 2 лет после его окончания. Учитывалась динамика выраженности неврологического дефицита по данным шкалы инвалидизации EDSS, наличие и длительность этапа стабилизации, темпы и варианты дальнейшего прогрессирования, характер прогноза, количество гадолиний-контрастированных повреждений по данным МРТ. С учетом этих показателей были разработаны критерии высокой, умеренной и низкой эффективности лечения. К моменту окончания курса митоксантрона высокая эффективность лечения в виде частичного регресса неврологического дефицита на фоне стабилизации была получена у 25 % больных при ВПТ и у 21,1 % — при ППТ с неопределенным характером прогноза; умеренная эффективность в виде стойкой стабилизации также преобладала у больных с неопределенным характером прогноза — у 50 % при ВПТ и у 36,8 % при ППТ; низкая эффективность в виде замедления темпов неуклонного варианта прогрессирования и его трансформации в более благоприятный поступательный вариант определялась у 22,9 % больных с ВПТ и у 26,3 % с ППТ с неблагоприятным характером прогноза. К моменту окончания двухлетнего катамнестического наблюдения позитивный терапевтический эффект митоксантрона с высокой и умеренной эффективностью сохранялся у 50 % больных при ВПТ и у 42,1 % — с умеренной эффективностью при ППТ. За этот период отрицательная динамика с избирательной реорганизацией показателей эффективности была получена у 20 (41,6 %) больных с ВПТ и у 11 (57,9 %) — с ППТ РС. Митоксантрон, по данным мониторинга МРТ, замедляет радиологическую активность воспалительного процесса, уменьшает число новых подтвержденных гадолиний-контрастируемых очагов поражения, но не оказывает влияния на общий нейродегенеративный процесс, который зависит от длительности, тяжести и типа течения РС с преобладанием при ППТ.Заключение. Доказана клиническая и радиологическая эффективность цитостатика митоксантрона в качестве метода деэскалационной иммуносупрессивной терапии при тяжелых малокурабельных прогредиентных формах РС с учетом типа течения, характера прогноза, степени выраженности неврологического дефицита, темпов и вариантов прогрессирования.

THE INFLUENCE OF TIMING OF SURGICAL TREATMENT OF CHILDREN WITH SPINAL CORD INJURY ON THE DYNAMICS OF NEUROLOGICAL DISORDERS

Objective. To assess the dynamics of neurological disorders in children with spine and spinal cord trauma in the thoracic and thoracolumbar spine, depending on the timing of surgery and the severity of spinal cord injury. Material and Methods . A total of 36 children aged 3 to 17 years were operated on for injuries to the thoracic spine and thoracolumbar junction accompanied by neurological deficit. Thoracic spine was damaged in 16 (44.4 %), thoracolumbar junction - in 20 (55.6 %) patients. Patients were divided into four groups based on time to surgery. Spinal bone lesions were assessed according to Magerl’s classification, and neurological disorders - to the ASIA scale. Results . Long-term results were followed for 5 years in all patients. Neurological function improvements in patients of Group 1 were observed in 1-2 days after surgery, Group 2 - in 2-3 days, Group 3 - in 5-7 days, and Group 4 - in 4-5 months. In Group 1 positive dynamics was observed as significant regression of sensory disorders, in Group 2 - as complete regression of neurological deficit in 2 patients, in Group 3 - as transition from C to D grade in 4 patients, from B to D grade in 2 patients, and 2 children had no regression. In Group 4 a regression of neurological disorders from B to C grade was observed in 6 children in 2-3 years, and 10 patients (A grade) had no improvement in neurological status. Conclusion . Complete and rapid recovery of neurological functions in children with complicated fractures of thoracic and thoracolumbar spine is observed after surgical treatment performed within the first 6-12 hours after injury, when neurological deficit is mainly caused by compression of the spinal cord and its elements, and secondary circulatory and pathological changes have not yet expressed.

SURGICAL TREATMENT OF L5-SPONDYLOLISTHESIS VERTEBRAE IN CHILDREN. BENEFITS OF POSTERIOR APPROACH

Objective to develop current options of surgical treatment of L5-spondylolisthesis in children. Materials and methods: 48 patients were observed and underwent surgical treatment at age of 10-17 years. In 9 patients spondylolisthesis of L5 was grade 2, in 14 - grade 3, in 12 - grade 4. 9 patients had spondyloptosis of the body of L5-vertebra. The article presents different options of surgical treatment of spondylolisthesis in children depending on the degree of vertebrae body shift and the main clinical manifestations. During surgery the anatomy of the vertebral canal and the normal interposition in the pathological segment were reconstructed. It resulted in normalization of the body balance and regression of neurological symptoms. Results: in spondylolisthesis grade 2 and 3 full reduction was achieved. In patients with grade 4 spondylolisthesis deformity was reduced to grade 2-3. Pain and radicular syndromes regressed in 2-3 days after surgery. In patients with monoparesis and contractures regression of neurological deficit took 1-1,5 months. Conclusions: The method of surgical treatment in patients with spondylolisthesis of L5 vertebrae depends on the degree of vertebrae shifting presence of segmental instability and neurological sighns.

ДИАГНОСТИКА И ХИРУРГИЧЕСКОЕ ЛЕЧЕНИЕ НЕБЛАГОПРИЯТНЫХ ПОСЛЕДСТВИЙ ПОЗВОНОЧНО-СПИННОМОЗГОВОЙ ТРАВМЫ

Objective. To analyze the content and results of specialized medical care delivered to patients with adverse consequences of spine and spinal cord injury. Material and Methods. The retrospective analysis included 307 patients treated for adverse consequences of the spine and spinal cord injury. Main reasons for low quality of life of patients and basic pathological conditions causing poor anatomical and functional results in them were studied. Results. Rational volume of surgery based on the clinical and X-ray data included decompression of the spinal cord and its roots, the spine release, correction of post-traumatic spinal deformities, anterior column reconstruction, and spinal fusion. Out of 257 patients with neurological disorders the regression was achieved in 156 (60.6 %) cases. Correction of posttraumatic deformity was 28.2° in the thoracic, 17.7° in the cervical, and 23.4° in the lumbar spine. Conclusion. Surgical treatment of the spine and spinal cord injury, even in its late period, is very effective and allows achieving partial or complete regression of neurological deficit and pain, permanent stabilization of the spine, correction of posttraumatic deformity, and significant improve in the function and quality of life of patients. Hir. Pozvonoc. 2014;(1):71-77.

Intracerebellar hemorrhage caused by superwarfarin poisoning

A 40-year-old man was admitted to stroke unit because of severe pain in the neck, occipital headache, followed by vomiting, numbness in his left arm, with accompanying hematuria. Brain CT scan showed left cerebellar hematoma associated with diffuse brain edema surrounding the fourth ventricle. Routine coagulation tests revealed abnormalities. Shortly after admission neurological deficit progressed, and he developed right-sided hemiparesis and consciousness disorder. Subsequently we learned that the patient several days before admission attempted suicide by ingesting an unknown quantity of rat poison, and diagnosed superwarfarin poisoning. He was treated surgically and conservatively with high doses of vit. K, which eventually led to a complete regression of neurological deficit.

Change in platelet monoamine oxidase activity in the acutest period of ischemic stroke is associated with the degree of neurological recovery

We studied monoamine oxidase activity (MAO) in platelets of patients in the acute period of ischemic stroke. Neurological deficit was evaluated by the data of clinical examinations and scales. In 80% patients MAO activity was considerably increased on 3-5 day after stroke. We found a correlation between increased MAO activity on 3-5 day after ischemic stroke and regression of neurological deficit on day 21 after ischemic stroke. The increase in MAO activity during the acute period of ischemic stroke is presumably a compensatory response aimed at stabilization of tissue homeostasis.

Effects of Early Correction of Energy and Free Radical Homeostasis on the Clinical and Morphological Picture of Cerebral Infarction

A randomized comparative prospective 35-day clinical-instrumental trial of 30 patients with ischemic hemispheric stroke hospitalized on the day of onset was performed. In the 16 patients of the study group, the antioxidant energy-correcting agent cytoflavin was added to basal treatment using the protocol: 20 ml/day by i.v. infusion on days 1–10; 2 tablets twice daily on days 11–35. The 14 reference patients received only basal treatment. Patients’ status was assessed at 0–24 h, and on post-stroke days 5, 11, 21, and 35. Neurological status was assessed using the Glasgow Scale, the NIH Stroke Scale, and the Mini Mental State Examination (MMSE); brain MRI scan scans were performed (to assess brain lesion volume); markers of antioxidant stress were assessed; functional disease outcomes were assessed using the Bartel index and a modified Rankin Scale. Early active correction of energy and free radical homeostasis with cytoflavin was found to lead to better improvements in morphological changes in the brain and free radical parameters, which correlated with the more significant and earlier (than in the control group) activation of consciousness and regression of neurological deficit; additional treatment also led to decreases in disability.

SURGICAL TREATMENT OF A PATIENT WITH FRACTURE-DISLOCATION IN THE THORACIC SPINE

The authors present a clinical observation of a patient with fracture-dislocation in the thoracic spine accompanied by neurological deficit and dysfunction of the pelvic organs. Surgical intervention was performed only through posterior approach. The treatment eliminated vertebromedullary conflict, restored anatomy of the spinal canal and injured spinal motion segment, and stabilized the injured spine. After surgery the regression of neurological deficits was noted, namely the restoration of sensitivity in the abdomen and thighs, sensation of bladder filling, and urges to urinate.

TREATMENT OF THORACIC AND LUMBAR SPINE AND SPINAL CORD INJURY IN CHILDREN

Objective. To assess results of surgical treatment and to develop an optimal management regiment of patients with spine and spinal cord injury. Material and methods. Twenty patients, age 9 to 17 years, with complicated unstable spinal injuries were operated on. Out of them 13patients had severe Frankel grades A, B, C neurological disorders, 7 patients – grades D and Er. Seventeen patients had burst fractures, one – seat-belt injury, and two – fracture-dislocations. Surgery was performed in the first hours following the trauma in 9 patients, within two weeks – in 9, and after 15 days – in two. Burst fractures with grades A, B, C were treated by simultaneous posterior reposition and fixation of the injured segment, and anterior decompression and fusion. Grade D and Er was treated initially by indirect posterior reduction and fixation of the involved segment. If neurological disorders still remained decompression and body fusion were performed. Posterior-lateral decompression and instrumental fixation were performed in cases of seat-belt injuries. Fracture-dislocation was treated by decompression laminoplasty, spinal canal revision, followed by posterior reposition and fixation. Results. Two patients with burst fractures and grade A neurological disorders have shown a regression to the grade D. Dynamics of neurological restoration to grades B and C was observed in 4patients. The patient with grade B has not shown any regression. A positive dynamics with motor function improvement was observed in 4 patients with grade C. Seven patients (6 with burst fractures, 1 with seat-belt trauma) with grade D and Er were operated on within first hours and day after the trauma. First stage of surgical treatment provided elimination of neurological deficit in 5 cases. Two patients with grade D required the second stage. Regression of neurological deficit was not achieved in patients with fracture-dislocations. Conclusion. Surgical treatment of patients with complicated spine and spinal cord injury should be performed within first 6–8 hours after the trauma.

Die rheumatisch bedingte Instabilität der oberen Halswirbelsäule

Rheumatic manifestation at the cervical spine occurs in more than 50% of all cases in the natural course of this disease. The first cervical manifestation takes place in the upper cervical spine. The initial involvement of the C1/C2 segment leads to atlantodental subluxation. Progressive destruction can result in vertical instability, which is characterized by cranial subluxation of the odontoid process with the danger of resulting stenosis and cervical myelopathy. The goal of diagnosis has to be the early recognition of these changes to establish an effective treatment protocol. Persistent pain, neurological deficits, and progressive radiological signs for instability are indications for operative stabilizing procedures. These procedures avoid progressive destruction and improve the prognosis regarding pain decrease, regression of neurological deficits, and life expectancy.

Different patterns of CSF neurotransmitter metabolism in patients with left or right hemispheric stroke

In 30 ischemic stroke patients, divided into 2 groups depending on the side of their hemispheric cerebral lesion, the authors evaluated the levels of CSF homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA). The changes of these metabolites in CSF samples collected 3, 14 and 25 days after stroke have been correlated to the clinical course. In both groups, which were similar in respect to the localization of the infarcted area and to the volume of the lesion, the levels of HVA and 5-HIAA increased in the first 2-3 days and gradually declined to normal values in the following 3 weeks, in parallel with the regression of neurological deficits. The increase of HVA and 5-HIAA was statistically significant only in left hemisphere-injured patients. A linear regression analysis between the clinical score values and the CSF levels of the two metabolites at different time-points of observation revealed a significant correlation only for the HVA in the left-lesioned patients.

Neurotoxicity of continuous (90 days) inhalation of technical grade methyl butyl ketone in hens.

Neurotoxicity was produced in 1-yr-old hens (five hens per treatment) by continual 90-d exposure in inhalation chambers to atmospheres containing 50, 100, 200, or 400 ppm technical grade methyl butyl ketone (MBK) containing 70% methyl n-butyl ketone (MnBK) and 30% methyl isobutyl ketone (MiBK). A 30-d observation period followed. Severity of clinical condition and progression or improvement of neurological deficit signs were dependent on the concentration of MBK and duration of exposure. Hens exposed to the two highest levels developed ataxia and paralysis; they died or were sacrificed before the designated exposure period ended. The intermediate level of MBK (100 ppm) caused severe ataxia; most treated hens showed no change in clinical condition during the observation period. Hens exposed to 50 ppm exhibited gross ataxia, with most demonstrating partial regression of neurological deficit after the exposure ceased. Hens exposed to the lowest tested level (10 ppm) remained normal. Only hens exposed to 400 or 200 ppm showed significant weight loss. Some hens from the 50-400 ppm treatment groups showed unequivocal histopathologic changes in the spinal cord and peripheral nerves. Severity of histopathologic changes depended on the level and duration of MBK exposure. These changes were characterized by excessive swelling, phagocytosis, degeneration, and demyelination of the axons.