Biomedical subjects

H R Machado

Publications and source records attributed to H R Machado.

At least 19 recordsLinked to original sources

PubMed2006

Relative frequency, clinical, neuroimaging, and postsurgical features of pediatric temporal lobe epilepsy.

We describe the relative frequency, clinical features, neuroimaging and pathological results, and outcome after pharmacological or surgical intervention for a series of pediatric patients with temporal lobe epilepsy (TLE) from an epilepsy center in Brazil. The medical records of children younger than 12 years with features strongly suggestive of TLE were reviewed from January 1999 to June 1999. Selected children were evaluated regarding clinical, EEG, and magnetic resonance imaging (MRI) investigation and divided into three groups according to MRI: group 1 (G1, N = 9), patients with hippocampal atrophy; group 2 (G2, N = 10), patients with normal MRI, and group 3 (G3, N = 12), patients with other specific temporal lesions. A review of 1732 records of children with epilepsy revealed 31 cases with TLE (relative frequency of 1.79%). However, when the investigation was narrowed to cases with intractable seizures that needed video-EEG monitoring (N = 68) or epilepsy surgery (N = 32), the relative frequency of TLE increased to 19.11 (13/68) and 31.25% (10/32), respectively. At the beginning of the study, 25 of 31 patients had a high seizure frequency (80.6%), which declined to 11 of 31 (35.5%) at the conclusion of the study, as a consequence of pharmacological and/or surgical therapy. This improvement in seizure control was significant in G1 (P < 0.05) and G3 (P < 0.01) mainly due to good postsurgical outcome, and was not significant in G2 (P > 0.1, McNemar's test). These results indicate that the relative frequency of TLE in children was low, but increased considerably among cases with pharmacoresistant seizures. Patients with specific lesions were likely to undergo surgery, with good postoperative outcomes.

Atrophy↗

PubMed2004

Cortical malformations are associated with a rare polymorphism of cellular prion protein.

Studies in animals lacking the cellular prion protein (PrP(c)) gene (Prnp) showed higher neuronal excitability in vitro and increased sensitivity to seizures in vivo. The authors previously reported a rare polymorphism at codon 171 (Asn-->Ser) of human Prnp to be associated with mesial temporal lobe epilepsy related to hippocampal sclerosis. They demonstrated that the same variant allele is also associated with symptomatic epilepsies related to different forms of malformations of cortical development.

Adolescent↗

PubMed2003

Surgical outcome in mesial temporal sclerosis correlates with prion protein gene variant.

BACKGROUND: Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) is the most common surgically remediable epileptic syndrome. Ablation of the cellular prion protein (PrP(c)) gene (PRNP) enhances neuronal excitability of the hippocampus in vitro and sensitivity to seizure in vivo, indicating that PrP(c) might be related to epilepsy. OBJECTIVE: To evaluate the genetic contribution of PRNP to MTLE-HS. METHODS: The PRNP coding sequence of DNA from peripheral blood cells of 100 consecutive patients with surgically treated MTLE-HS was compared to that from a group of healthy controls adjusted for sex, age, and ethnicity (n = 180). The presence of PRNP variant alleles was correlated with clinical and presurgical parameters as well as surgical outcome. RESULTS: A variant allele at position 171 (Asn-->Ser), absent in controls, was found in heterozygosis (Asn171Ser) in 23% of patients (p < 0.0001). The PRNP genotypes were not correlated with any clinical or presurgical data investigated. However, patients carrying the Asn171Ser variant had a five times higher chance of continuing to have seizures after temporal lobectomy (95% CI 1.65 to 17.33, p = 0.005) than those carrying the normal allele. At 18 months after surgery, 91.8% of patients with the normal allele at codon 171 were seizure free, in comparison to 68.2% of those carrying Asn171Ser (p = 0.005). CONCLUSIONS: The PRNP variant allele Asn171Ser is highly prevalent in patients with medically untreatable MTLE-HS and influences their surgical outcome. The results suggest that the PRNP variant allele at codon 171 (Asn171Ser) is associated with epileptogenesis in MTLE-HS.

Adult↗

PubMed2002

Accuracy of ictal SPECT in mesial temporal lobe epilepsy with bilateral interictal spikes.

OBJECTIVE: In mesial temporal lobe epilepsy (MTLE), the rate of correct seizure lateralization of ictal semiology and ictal EEG is better for patients with unilateral interictal spikes (UIS) than for patients with bilateral interictal spikes (BIS), possibly due to rapid seizure propagation patterns associated with bilateral epileptogenesis. In this study, the authors investigated if ictal SPECT is a reliable diagnostic test for both UIS and BIS patients. METHODS: Video-EEG recording was used as the gold standard to examine the accuracy of ictal SPECT and its relationship with interictal and ictal EEG. Ninety-three consecutive patients with MTLE associated with hippocampal sclerosis were included in the analysis. Ictal SPECT was considered accurate if two blinded observers independently lateralized the scan correctly. RESULTS: Ictal SPECT correctly lateralized 75 (80.6%) of 93 scans. The rate of correct seizure lateralization was 87.6% for the UIS group and only 55.0% for the BIS group (p = 0.0027). In the EEG epochs, 66.7% of BIS patients vs 43.4% of UIS patients had nonlateralized ictal EEG (p < 0.001). CONCLUSION: The authors conclude that the accuracy of ictal SPECT is worse for MTLE patients with BIS than for those with UIS. The role of ictal SPECT in presurgical evaluation of patients with BIS must be reviewed.

Acute Disease↗

PubMed2002

Glucocorticoid receptor gene polymorphisms in ACTH-secreting pituitary tumours.

OBJECTIVE: The inhibitory action of glucocorticoids on the hypothalamic-pituitary axis is disrupted in ACTH-secreting pituitary tumours. The molecular events leading to the development of these tumours and their relative resistance to glucocorticoids are unknown. We investigated the presence of mutations and polymorphisms of the glucocorticoid receptor (GR) gene in corticotropinoma and their possible relationship with the tissue-specific resistance to glucocorticoids. DESIGN AND METHODS: DNA or RNA was extracted from 18 corticotropinomas and the GR gene was amplified by the polymerase chain reaction (PCR) or reverse transcriptase-PCR followed by automated direct sequencing. RESULTS: We did not identify any mutation in the coding region and the exon-intron boundary regions of the GR gene. The polymorphism AAT > AGT at codon 363 (N363S) was found in 17% and the polymorphism AAT > AAC at codon 766 (N766N) in 11% of tumours, both in heterozygous state. The polymorphisms at codons 22 and 23, at introns 3 and 4, and at codon 618, previously described in normal population, were not observed. CONCLUSIONS: Our results show that GR gene mutations are rare and unlikely to contribute to the glucocorticoid resistance observed in corticotropinomas. Polymorphisms in the GR gene might confer a selective advantage to tumorigenesis in corticotropinoma. However, there was no relationship between GR gene polymorphism and clinical presentation, tumour size or surgery outcome, suggesting that tumour growth may not be directly related to alterations of the GR gene structure.

Adenoma↗

PubMed1999

[Transfontanellar Doppler ultrasound measurement of cerebral blood velocity before and after surgical treatment of hydrocephalus].

Twenty-seven children with hydrocephalus of different etiologies diagnosed by clinical examination, neurosonography and computerized brain tomography were submitted to transfontanellar US-Doppler evaluation for measurement of blood flow velocity and for the calculation of resistance index (RI) in the anterior and middle cerebral arteries and internal carotids. All children were submitted to evaluation before surgery and on the 1st, 30th and 60th postoperative days. We conclude that neurosonography and US-Doppler technique is useful for determination of hydrocephalus, indication and control of cerebrospinal fluid shunts and monitoring of changes in RI, comparing data obtained immediately before and after surgery and during the late postoperative period. The results obtained when comparing the RI values for the various arteries during the different stages of the study also permitted us to conclude that the anterior cerebral arteries are representative of the maximal alterations that occur in cerebral vascular resistance in pediatric patients with hydrocephalus.

Blood Flow Velocity↗

PubMed1996

Subarachnoid hemorrhage after aneurysm surgery.

The surgical treatment of intracranial aneurysms by clipping is recognized as effective and definitive. However some cases that suffered a new subarachnoid hemorrhage (SAH) some time after they were submitted to aneurysm clipping have raised doubts about the concept of "cure" after this treatment. Eleven patients previously submitted to aneurysm clipping who presented a new SAH were analyzed. The time elapsed from surgery to SAH varied from 3 to 10 years. After SAH four patients had a poor outcome. The new episode of SAH occurred due to intrinsic factors of the cerebral vasculature: 1. a weak point of the vessel wall near the previous aneurysm, 2. a weak point of another vessel far from the previous aneurysm, 3. a previous infundibular dilation of the posterior communicating artery; and due to technical problems: 1. aneurysm not identified during the previous treatment, 2. aneurysm deliberately left untreated, 3. persistence of the aneurysm due to inappropriate surgery, 4. persistency of part of the aneurysm neck after clipping and 5. slipping of the clip from the neck of the aneurysm. The measures to prevent new SAH after surgery start with adequate preoperative angiographic studies, a careful inspection of the position of the clip and emptying of the aneurysm. Early angiography studies may reveal a persistent neck and later ones may reveal newly developed aneurysms. In conclusion, SAH after aneurysm clipping is a late and severe phenomenon and the concept of "cure" after this surgery should be interpreted with caution.

Adult↗

PubMed1996

Intramedullary spinal cord paracoccidioidomycosis. Report of two cases.

Two cases of intramedullary paracoccidioidomycosis are reported. Paracoccidioidomycosis is a systemic disease that involves the buccopharyngeal mucosa, lungs lymph nodes and viscera and infrequently the central nervous system. Localization in the spinal cord is rare. Case 1: a 55-year old male admitted with crural pararesis, tactile/painful hypesthesia and sphincter disturbances of 15 days duration. Cutaneous-pulmonary blastomycosis was diagnosed 17 years ago. Myelotomography showed a blockade of T3-T4 (intramedullary lesion). The lesion surgically removed was a Paracoccidioides brasiliensis granuloma. Treatment with sulfadiazine was started after the surgery. Follow-up of 15 month showed an improvement of the clinical signs. Case 2: a 57-year old male was admitted elsewhere 6 months ago and, with a radiologic diagnosis of pulmonary paracoccidioidomycosis, was treated with amphotericin B. He progressively developer paresthesia and tactile/pain anaesthesia on the left side, sphincter disturbances and tetraparesis with bilateral extensor plantar response and clonus of the feet. Myelotomography showed a blockade of C4-C6 (intramedullary lesion). The lesion was not found during surgical exploration and the patient deteriorated and died. Post-mortem examination revealed an intramedullary tumor above the site of the mielotomy (Paracoccidioides brasiliensis granuloma). The preoperative diagnosis of intramedullary paracoccidioidomycotic granulomas is difficult because the clinical and radiologic manifestations are uncharacteristic. Clinical suspicion was possible in our cases based on the history of previous systemic disease. Contrary to intracranial localizations, paracoccidioidomycotic granulomas causing progressive spinal cord compression may require early surgery because response to clinical treatment is slow and the reversibility of neurological deficits depends on the promptness of the decompression.

Granuloma↗

PubMed1994

Cysticercosis of the central nervous system. I. Surgical treatment of cerebral cysticercosis: a 23 years experience in the Hospital das Clínicas of Ribeirão Preto Medical School.

Cysticercosis is the most frequent parasitosis of the nervous system and nowadays it is widespread through the world. Despite the development of anticysticercal drugs (praziquantel and albendazole), their efficacy is more marked in cases with parenchymal active cysts and they do not prevent complications such as hydrocephalus. Thus, many patients with neurocysticercosis require surgical intervention, generally of palliative nature, but that may occasionally produce a cure. The clinical outcome of 180 patients with cerebral cysticercosis who underwent surgical treatment form 1970 to 1993 was analyzed. Surgical treatment was performed to control increased ICP in 177 patients and due to local compression of cranial nerves or brainstem in five. Some patients had more than one surgical procedure, totalizing 287 interventions. Increased intracranial pressure (ICP) was caused by hydrocephalus in 91%, by intracranial mass lesion (tumoral form) in 6.2% and by pseudotumor cerebri (pseudotumoral form) in 2.8% of the case. Based on the pathophysiological mechanisms of intracranial hypertension identified through conventional CT-scan, ventriculography, cysternotomography, ventriculotomography and MRI, different surgical approaches were indicated. Patients with tumoral form were submitted to direct approach and cyst removal and generally they had benefits from this procedure. Patients with pseudotumoral form whose clinical treatment failure underwent decompressive craniectomies and had a poor outcome (40% of good results). Direct removal of ventricular/cisternal cysts and/or ventriculoatrial/peritoneal shunting (VA/VPS) was performed in patients with hydrocephalus. Removal of free ventricular cysts in patients who had no ependimitis/arachnoiditis generally allowed a good outcome. Patients with adherent cysts and inflammatory process needed a VA/VPS posteriorly and the outcome was not so good. One hundred thirty-two patients were submitted to VA/VPS (109 as the first procedure and 23 after another surgical treatment). The VA/VPS was effective to control increased ICP, despite many complications observed mainly during the two first postoperative years. After this period the surviving patients generally had a better outcome. The patients submitted to cyst removal due to local compression of cranial nerves/brainstem generally had good results. Based on the experience acquired with the management of these patients we present our recent policy for the treatment of patients with neurocisticercosis.

Adolescent↗

PubMed1994

Cysticercosis of the central nervous system. II. Spinal cysticercosis.

The compromising of the spinal canal by cysticercus is considered infrequent, varying from 16 to 20% in relation to the brain involvement. In the spinal canal the cysticercus predominantly places in the subarachnoid space. Clinical signs in spinal cysticercosis can be caused by direct compression of the spinal cord/roots by cysticerci and by local or at distance inflammatory reactions (arachnoiditis). Another mechanism of lesion is degeneration of the spinal cord due to pachymeningitis or circulatory insufficiency. The most frequent clinical features are signs of spinal cord and/or cauda equina compression. The diagnosis of spinal cysticercosis is based on evidence of cerebral cysticercosis and on neuroradiological examinations (myelography and myelo-CT) that show signs of arachnoiditis and images of cysts in the subarachnoid space and sometimes, signs of intramedullary lesions, but the confirmation can only be made through immunological reactions in the CSF or during surgery. The clinical course of 10 patients with diagnosis of spinal cysticercosis observed among 182 patients submitted to surgical treatment due to this disease are analyzed. The clinical pictures in all cases were signs of spinal cord or roots compression. All but two presented previously signs of brain cysticercosis. Neuroradiological examinations showed signs of arachnoiditis in 4 patients, images of cysts in the subarachnoid space in 5, and signs of arachnoiditis and images of cysts in one. The 6 patients that presented intraspinal cysts were submitted to exeresis of the cysts and 2 patients with total blockage of the spinal canal underwent surgery for diagnosis. The 2 remaining patients with arachnoiditis and blockage of the spinal canal were clinically treated. All of the six patients submitted to cyst exeresis had initial improvement but 4 of them later developed arachnoiditis and recurrence of the clinical signs and only 2 remained well for long-term. The 2 non operated patients had no improvement of their clinical signs. Two patients died later due to complications of cerebral cysticercosis. Based on the experience acquired in the management of these patients we indicate surgical treatment for patients that present free cyst in subarachnoid space. For those who present arachnoiditis, surgery is indicated only when there is doubt in the diagnosis. Intramedullary cysts should also be surgically treated.

Adolescent↗

PubMed1994

[Congenital cerebral arteriovenous fistula. Diagnostic peculiarity and surgical repair in an infant with heart failure].

A case of 3 month-old-boy with Down's syndrome and heart failure due to a localized arteriovenous fistula of the cranial vessels is reported. Clinical diagnosis was made after cranial bruit detection based on a retroauricular thrill incidentally felt by the mother. The diagnosis was confirmed by digital subtraction angiography and a good result was achieved by means of embolization and surgical ligation of the fistula. Three years after the operation the patient is asymptomatic, on no medication and with normal magnetic resonance image of the cranial vessels.

Angiography, Digital Subtraction↗

PubMed1993

Isolated fourth ventricle in neurocysticercosis: pathophysiology, diagnosis, and treatment.

Four cases of isolated fourth ventricle in neurocysticerocosis are reported (three after ventriculoperitoneal shunting, and one after hydrocephalus without shunting). Diagnosis was made based on computed tomography (CT) and/or CT cisternogram/ventriculogram. Three patients underwent fourth ventricle drainage (two died and the third remains well). The fourth patient refused surgical treatment and continues to have severe ataxia. Diagnosis, pathophysiology, and treatment of this entity in neurocysticercosis are discussed.

Adult↗

PubMed1993

Longitudinal evaluation of adrenocorticotrophin and beta-lipotrophin plasma levels following bilateral adrenalectomy in patients with Cushing's disease.

OBJECTIVES: Bilateral adrenalectomy may be indicated in patients with Cushing's disease in whom hypercortisolism is not resolved after pituitary microsurgery. However, Nelson's syndrome is a major long-term complication of such therapy. We have carried out a longitudinal study on patients with Cushing's disease who underwent bilateral adrenalectomy comparing plasma beta-lipotrophin (beta-LPH) with ACTH levels. PATIENTS AND METHODS: Seven patients unsuccessfully treated by pituitary surgery for Cushing's disease underwent bilateral adrenalectomy. Blood samples were collected on days 8 and 15 and at 1, 2, 3, 6, 9, 12, 18 and 24 months after adrenalectomy in all patients. Five patients were followed up for the longer periods of 30, 33, 39, 72 and 84 months respectively. Plasma ACTH and beta-LPH were determined by RIA after extraction. Pituitary CT scan was done at 6-8 month intervals. RESULTS: A pituitary tumour was detected in three patients at 14, 24 and 26 months after adrenalectomy respectively. The basal ACTH (range 8-21 pmol/l) began to rise between 15 and 30 days and exhibited a sharp increase with a range of 36-114 pmol/l at 3 months and a range of 53-187 pmol/l at 6-9 months after adrenalectomy. The ACTH levels in the three patients who later presented with a pituitary tumour were indistinguishable from those observed in the other patients up to 12 months after adrenalectomy. Only at 12 months or thereafter were their ACTH levels higher than in the other patients (958 +/- 252 vs 205 +/- 22 pmol/l). beta-LPH concentrations changed in parallel with ACTH levels. The ACTH levels correlated positively with beta-LPH levels (r = 0.76). CONCLUSIONS: In patients with Cushing's disease undergoing bilateral adrenalectomy, plasma ACTH and beta-LPH concentrations cannot predict the development of pituitary tumours until 12 months after surgery.

Adolescent↗

PubMed1993

[Surgical treatment of intracranial aneurysms: comparison between early and late surgery].

The clinical course of patients with subarachnoid hemorrhage (SAH) due to rupture of cerebral aneurysm admitted during the last five years is analysed: 157 patients were treated by direct surgical approach of the aneurysm, 58 localized in the anterior communicating artery (ACoA), 48 in the internal carotid artery (ICA), 43 in the middle cerebral artery (MCA), and 8 in the posterior circulation. Fourty-four patients were operated on during the first 72 hours (early surgery), 40 during the 4th and 7th days, 16 during the 8th and the 10th, and 57 after the 10th (late surgery). According to main localizations, the outcome of patients with aneurysms in the ACoA was good in 79.1%, in the ICA in 69.7%, and in the MCA in 69.7%. Patients treated in Hunt & Hess grade I and II had both good results in 77.5%, grade III patients had good results in 71.3%, and grade IV in 56.2%. According to timing of surgery good results were observed in 61.4% for patients submitted to early surgery, in 80% for patients treated during the 4th and 7th days, in 81.2% for patients treated during the 8th and the 10th days, and in 70.2% for that submitted to late surgery. The overall mortality was 14.6%. For grade I patients mortality was 6.4%, for grade II was 12.2%, for grade III was 15.2%, for grade IV was 25%, and all patients operated on in grade V died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Long-term results after lateral canthal advancement for unilateral coronal synostosis.

The procedure of lateral canthal advancement was carried out to correct unilateral coronal synostosis in 39 consecutive patients at The Hospital for Sick Children during a 20-year period. Thirty-seven children were available for follow-up study, and results were considered to be good or excellent in 81% of them. Liberation of the supraorbital margin and release of stenotic skull base sutures are crucial for a successful result. The severity of the process and the age of the patient were not restrictive factors in regard to indication for this procedure. Some patients showed a continuous improvement with time. Morbidity was minimal. It is suggested that lateral canthal advancement is the procedure of choice for unilateral coronal synostosis.

Child↗

PubMed1991

Infantile hydrocephalus: brain sonography as an effective tool for diagnosis and follow-up.

Infantile hydrocephalus is a common disease. In most affected children the process starts before the age of 2 when the bregmatic fontanel is still open. Brain sonography has emerged as an effective tool in diagnosing progressive ventricle dilation and may be used for continuous follow-up. It gives such important information as: (a) cortical thickness, an expression of proper shunt function and of prognostic value concerning neuropsychological development; (b) position of the tip of the catheter, which is considered by some to be a predictive factor of shunt failure; (c) other complications such as subdural collections, isolated IV ventricle, and slit ventricles. This methodology permits frequent examinations and allows better comprehension of the pathological process by the parents and medical staff.

Cerebral Ventricles↗

PubMed1991

Gelastic seizures treated by resection of a hypothalamic hamartoma.

A 7-year-old girl presented for evaluation of a peculiar kind of epilepsy. Her seizures began before 1 year of age and consisted of episodes of brief, uncontrolled and unprovoked laughter than with time progressed to include cursive, complex partial and generalized tonic-clonic seizures. Progressive impairment of cognitive functions was noted as well as precocious puberty. Neuroimaging examination disclosed a hypothalamic hamartoma. It was excised by a pterional approach, and no further seizures were noted. The authors propose direct surgery for the hypothalamic hamartoma as a treatment for this progressive syndrome.

Child↗

PubMed1990

[Infantile hydrocephalus: long-term results in 102 patients and the importance of neurosonography].

A personal series (in 94% of the cases) of 102 children who underwent 170 procedures (1.66 procedures/patient) for hydrocephalus has been followed for 5 1/2 years (Jan-83 to June-88). Most of the children were under two years of age (80%) and in these cases brain sonography was the examination of choice for both diagnosis and follow-up (307 examinations, 4.4 per patient). Only occasionally was computed tomography necessary for better study in these cases. Our results suggest that there was no significant difference between our cases and those published in the literature concerning the number or procedures/patient (1.66)., infection rate (5.2%), mortality rate (6.8%) and intellectual performance. We recommend the use of brain sonography both in diagnosis and follow-up studies for hydrocephalic children since this examination is innocuous, inexpensive and easy to perform by neurosurgeons. Also it provides a good interaction between the examiner, the child and the parents, which is of utmost importance for the comprehension of the disease by the parents and early diagnosis of complications by the neurosurgeon.

Cerebrospinal Fluid Shunts↗