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Biomedical subjects

I Alfonso

Publications and source records attributed to I Alfonso.

At least 19 recordsLinked to original sources
PubMed2006

[Treatment of herpes simplex encephalitis in children].

INTRODUCTION: Herpes simplex encephalitis (HSE) is a focal infectious disease of the central nervous system (CNS) acknowledged the world over as being severe. DEVELOPMENT: The epidemiology is well known in developed countries. It presents in patients over the age of 3 months. The mechanism by which the virus reactivates and penetrates into the CNS is still not fully understood. A timely diagnosis is crucial so that early treatment can be established within the first four days of the infectious process. By so doing, it becomes possible to raise the chances of survival by over 50%. The physician should have a strong suspicion when faced with a patient with symptoms of encephalitis, especially if he or she has focal neurological manifestations, including manifestations in the neuropsychiatric sphere. The non-invasive diagnostic method par excellence is high-sensitivity magnetic resonance imaging studies of the brain within the first 24-48 hours following the onset of the clinical signs and symptoms. Determination of viral DNA in cerebrospinal fluid by the polymerase chain reaction method is the technique with the highest degree of sensitivity and specificity available for carrying out the diagnosis. Effective treatment is intravenous acyclovir: 30 mg/kg/day in three doses. CONCLUSIONS: Encephalitis produced by the herpes virus is a disease that is dreaded because of the high mortality rate and the devastation it causes in the living conditions of survivors. Our aim is to stimulate the clinical suspicion of HSE so that pharmacological treatment can be established even while diagnostic tests are being carried out. We suggest early neuropsychological evaluation and follow-up of the manifestations of focal sequelae related to the frontotemporal regions.

Child↗
PubMed2006

[Cerebrovascular accidents in full-term newborn infants].

INTRODUCTION: The purpose of this paper is to review the role of the neurologist in the management of cerebrovascular accidents (CVA) (insults resulting from a sudden obstruction or rupture of an intracranial vessel). This was accomplished by reviewing the literature (PubMed) under the heading of stroke and term neonate. DEVELOPMENT: CVA in full-term neonates are classified as hematomas and infarcts. Hematomas are classified according to: location, structure (arterial, venous, or sinus), type of malformation (aneurysm, venous malformation, and telangiectasia), and cause of the bleed (vessel wall rupture or hypo-coagulation). Classification according to location is based on compartment supra or infratentorial; space -extra-axial (epidural, subdural, or subarachnoid) or intra-axial (parenchymal or ventricular)-; and region -parietal, temporal, thalamic, etc.-. Infarcts are classified according to vascular and parenchymal factors. The vascular factors are the structure, the cause of the obstruction -extramural, mural or intramural (thrombus or embolus)-. The parenchymal factors are type of damage (pale vs hemorrhagic) and location. Patients with suspected embolism should have ultrasound neck. Coagulation studies should be done in patients with hematomas and infracts. Multiple causes may be present in each case. Anticoagulation is only used in small pale infarcts of cardiac embolic origin. CONCLUSION: The neurologist roles in the management of CVA are to classify the event, select the appropriate investigation, and implement treatment.

Humans↗
PubMed2006

[Executive function disorders].

AIM: To review the development, anatomy and physiology of executive functions (EF) in normal and pathological conditions. DEVELOPMENT: EF consist of several internal mental process design to solve mental and environmental complex problems in an efficient and acceptable way to the person and the society. EF include inhibition of behavior and irrelevant information, nonverbal working memory, verbal working memory, self-regulation of affect, motivation and arousal, planning, decision making, self monitoring of the entire solving problem process and self evaluation of the results of the action taken. The anatomical substrate is at the prefrontal lobe cortex and its afferent and efferent structures. Neurotransmitters involved in activation of neurons at the prefrontal cortex are dopamine and norepinephrine and in less degree acetylcholine and serotonine. CONCLUSIONS: Disorders of one or more of the EF in children and adolescents are found in attention deficit/hyperactivity disorder, Tourette syndrome, bipolar disease, depression, obsessive-compulsive disorders, autism and traumatic brain injury.

Adolescent↗
PubMed2003

Outcome after later combined brachial plexus and shoulder surgery after birth trauma.

Of 22 infants aged between 11 and 29 months who underwent a combined reconstruction of the upper brachial plexus and shoulder for the sequelae of a birth injury, 19 were followed up for two or more years. The results were evaluated using a modified Gilbert scale. Three patients required a secondary procedure before follow-up. Three patients had a persistent minor internal rotation contracture. All improved by at least two grades on a modified Gilbert scale.

Brachial Plexus↗
PubMed2001

Internal carotid artery thrombus: an underdiagnosed source of brain emboli in neonates?

We report a full-term neonate with a left middle cerebral artery infarct, narrowing of the internal carotid artery detected by magnetic resonance angiography and B-mode ultrasonography, and a large thrombus at the origin of the internal carotid artery detected by B-mode ultrasonography. Internal carotid arterial thrombus is seldom considered the source of middle cerebral arterial embolus in neonates. We suggest that B-mode ultrasonography of the carotid artery be included in the diagnostic evaluation of middle cerebral artery infarcts in neonates.

Carotid Artery Thrombosis↗
PubMed2001

Continuous-display four-channel electroencephalographic monitoring in the evaluation of neonates with paroxysmal motor events.

The objective of this study was to determine the value of continuous-display four-channel electroencephalographic (EEG) monitoring to distinguish epileptic front nonepileptic paroxysmal motor events. Five full-term neonates with paroxysmal motor events were included in the study. Nurses were instructed to print contiguous pages of the continuous-display four-channel EEG monitoring and to activate the event marker on the simultaneously conducted continuous video-EEG telemetry unit during each paroxysmal motor event. The printouts from the continuous-display four-channel EEG monitoring were interpreted and compared with the corresponding segments of continuous video-EEG telemetry. Thirty paroxysmal motor events were captured. Sixteen paroxysmal motor events were epileptic, and 14 were nonepileptic. The interpretation of the printouts of the continuous four-channel EEG monitoring concurred with an independent interpretation of the corresponding video-EEG telemetry segments in all of the events. Continuous-display four-channel EEG monitoring is a valuable tool in the evaluation of neonates with paroxysmal motor events since it reliably distinguishes epileptic and nonepileptic events.

Electroencephalography↗
PubMed2000

Optically active dioxatetraazamacrocycles: chemoenzymatic syntheses and applications in chiral anion recognition

Two new C2 and D2 symmetrical dioxatetraaza 18-membered macrocycles [(R,R)-1 and (S,S,S,S)-2] are efficiently synthesized in enantiomerically pure forms by a chemoenzymatic method starting from (+/-)-trans-cyclohexane-1,2-diamine. The protonation constants and the binding constants with different chiral dicarboxylates are determined in aqueous solution by means of pH-metric titrations. The triprotonated form of (S,S,S,S)-2 shows moderate enantioselectivity with malate and tartrate anions (deltadeltaG=0.62 and 0.66 kcal mol(-1), respectively), being the strongest binding observed in both cases with the L enantiomer. Good enantiomeric discrimination is obtained with tetraprotonated (R,R)-1 and N-acetyl aspartate, the complex with the D-enantiomer being 0.92 kcalmol(-1) more stable than its diastereomeric counterpart. Despite the lack of enantioselectivity of tri- and tetraprotonated (R,R)-1 for the tartrate anion, a very good diastereopreference for meso-tartrate is found. All these experimental results allow us to propose a model for the host-guest structure based on coulombic interactions and hydrogen bonds.

Journal Article↗
PubMed2000

Neoplasm as a cause of brachial plexus palsy in neonates.

Two patients with neonatal onset of arm weakness resulting from neoplastic involvement of the brachial plexus who were initially considered to have obstetric brachial plexus palsies are reported. The first patient was a 7-day-old female who presented with a left supraclavicular mass that was first detected at 2 days of age and left proximal arm weakness. The weakness involved the whole arm within 3 days. The mass was a malignant rhabdoid tumor. The second patient was a 28-month-old male who presented with slowly progressive right arm weakness, which began at 3 weeks of age, and episodes of scratch marks on the arm that began at 4 months of age. Magnetic resonance imaging revealed a plexiform neurofibroma of the brachial plexus. The features that are suggestive of a brachial plexus palsy caused by a neoplasm rather than of obstetric brachial plexus palsy include the following: the onset of weakness after the first day of age, with a progressive course; a history of a normal delivery and birth weight; the absence of signs of a traumatic injury or injuries; the appearance before 7 days of age of a growing supraclavicular mass without radiographic evidence of a clavicular fracture; and recurrent scratch marks on the weak arm.

Arm↗
PubMed2000

Focal upper extremity neuropathy in neonates.

Focal upper extremity neuropathies are common in neonates. The brachial plexus is the most common site involved. Brachial plexus injuries may involve different structures, thus producing different clinical presentations: complete brachial plexus palsy, Duchenne-Erb palsy, upper-middle trunk brachial plexus palsy, Klumpke palsy, fascicular brachial plexus palsy, and bilateral brachial plexus palsy. The causes of brachial plexus palsy are obstetric injury, intrauterine compression, humeral osteomyelitis, hemangioma, exostosis of the first rib, neck compression, and neoplasm. The differential diagnosis of brachial plexus palsy includes pseudoparesis, amyoplasia congenita, congenita varicella syndrome, and neurological lesions at other neuroanatomical levels. The cause and the degree of injury dictate the prognosis. The prognosis of obstetric brachial plexus injury is usually good.

Arm Injuries↗
PubMed2000

Neurophysiological evaluation of children with traumatic radiculopathy, plexopathy, and peripheral neuropathy.

Neurophysiological evaluation of children with traumatic peripheral nervous system injury is accomplished with electromyography, motor and sensory nerve conduction studies, and somatosensory and motor-evoked potentials. Preoperative neurophysiological tests are performed if motor deficits persist for more than 3 months. Evidence of reinnervation on these neurophysiological tests predates clinical recovery by weeks, hence they help determine the site of the lesion and provide objective measures for selecting candidates for surgical exploration. Intraoperative neurophysiological tests help to identify and confirm the integrity of nerves and to develop the optimal surgical strategy. Postoperative evaluations every 3 to 6 months may determine efficacy of treatment.

Brachial Plexus Neuropathies↗
PubMed2000

Single photon emission computed tomographic evaluation of brainstem release phenomenon and seizure in neonates.

We report the ictal brain single photon emission computed tomographic (SPECT) findings in two neonates. One neonate had hypoxic-ischemic encephalopathy, a disorganized discontinuous electroencephalogram (EEG) background, lethargy, seizures, and brainstem release phenomena. A brain SPECT was performed during a brainstem release phenomenon characterized by a 34-second sustained tonic posture of the right arm and chewing. It did not reveal focal cerebral hemisphere hyperfusion. The second neonate had hemimegalencephaly, low-voltage irregular EEG background, and seizures. A brain SPECT was performed during a seizure characterized by a 32-second sustained tonic posture of the right arm. It revealed focal hyperperfusion in the posterior region of the left hemisphere. The brain SPECT findings in these patients indicate that despite clinically similar events, brainstem release phenomena and seizures have different perfusion characteristics, and refute the theory that brainstem release phenomena are due to epileptic foci in the cerebral hemispheres undetectable by EEG.

Brain↗
PubMed2000

Intravenous valproate dosing in neonates.

The loading dosage of intravenous valproate required to achieve a desired serum concentration in neonates is not known. Two neonates with seizures received loading doses of intravenous valproate over 30 minutes. Serum valproate concentrations were measured 45 minutes and 3 hours after initiation of the infusion. Both neonates had received phenobarbital and phenytoin before the loading infusions. In the first patient, a loading dose of intravenous valproate of 10 mg/kg increased the 45-minute postinfusion serum valproate concentration to 41 microg/mL with a 3-hour postinfusion serum valproate concentration of 33 microg/mL. In the second patient, a loading dose of 25 mg/kg increased the 45-minute postinfusion serum valproic acid concentration to 100 microg/mL with a 3-hour postinfusion serum valproic acid concentration of 78 microg/mL. We found that each 1 mg/kg of intravenous valproate increased the 45-minute and 3-hour postinfusion serum valproic acid concentrations by approximately 4 microg/mL and 3 microg/mL, respectively. We suggest that these figures be used to calculate the desirable loading dose of intravenous valproate in neonates until larger studies are conducted. The volume of distribution and the serum clearance of valproate were approximately 0.245 L/kg and 25 mL/h/kg, respectively.

Anticonvulsants↗
PubMed1998

Similar brain SPECT findings in subclinical and clinical seizures in two neonates with hemimegalencephaly.

Brain single-photon emission computed tomography (SPECT) findings during clinical and subclinical seizures were compared in two neonates with hemimegalencephaly. Interictal and ictal brain SPECT were performed in two neonates. The ictal studies were performed during a clinical seizure in one neonate and during a subclinical seizure in another neonate. They revealed similar focal hemispheric hyperperfusion at the electroencephalographic seizure foci in both cases. The similar perfusion patterns imply that clinical and subclinical seizures place similar metabolic demands on the cerebral tissue involved in the generation of electroencephalographic seizures in neonates with cerebral dysgenesis and suggest that clinical and subclinical seizures should be treated similarly in this population.

Brain↗
PubMed1998

[Clinical presentations, differential diagnosis and management of obstetric brachial palsy].

INTRODUCTION: The brachial plexus originates from C5 to T1 spinal segments. The brachial plexus includes the ventral ramus, trunks, divisions, cords and branches. DEVELOPMENT AND CONCLUSIONS: Brachial plexus injuries produce clinical syndromes. The Duchenne-Erb syndrome is the most frequent presentation of obstetric brachial plexus injury. The differential diagnosis of brachial plexus palsy include decreased arm movements due to pain, or weakness caused by a lesion of the nervous system outside in the brachial plexus, or by a lesion in the brachial plexus due to non-obstetrical causes. Management of these patients initially includes considering the possibility of clavicular and humeral fractures and posterior subluxation of the shoulder; and subsequently considering the possibilities of subscapularis muscle contraction or posterior shoulder subluxation in patients that develop internal rotation contracture of the shoulder; or flexion, pronation or supination contracture in patients with forearm deformation. Treatment consist of physical therapy, administration of botulinum toxin, electrical stimulation, neurolysis, nervatization, removal of neuromas and nerve grafting, treatment of fractures and subluxation, release of muscle contracture and tendon transplantation.

Brachial Plexus↗
PubMed1998

[Neurophysiological assessment of children with obstetric brachial plexus palsy].

INTRODUCTION: The objectives of the neurophysiological evaluation of infants with brachial plexus palsy are to determine the time of occurrence of the lesion, to locate the lesion and to determine its course. METHODS AND CONCLUSIONS: These objectives are achieved by studying affected upper extremity muscles by needle electromiography (EMG) and affected nerves by motor and sensory conduction studies. EMG is performed in the first week of life in those patients with brachial plexus palsy of unknown etiology to determine the age of the lesion for medico-legal reasons. EMG is performed before surgery for tendon transfer in the selected muscles to assure that they are normal. EMG and motor and sensory conduction studies are performed at the age of 3 and 6 months in infants with less than 4 muscle weakness to determine candidates for surgical exploration. Motor and sensory nerve conduction studies are performed intraoperative to determine the functional status of the affected axons and the best surgical procedure (neurotization, neurolysis and/or neuroma resection and homologous nerve graft).

Brachial Plexus↗
PubMed1998

[Surgical treatment of children with brachial plexus paralysis].

OBJECTIVE AND METHODS: A variety of surgical procedures exist for early repair of the nerve injury in obstetrical brachial plexus palsy, including neuroma excision and nerve grafting, neurolysis and neurotization. Secondary deformities of the shoulder, forearm, and hand can similarly be reconstructed using soft tissue and skeletal procedures. This review describes our surgical approach to maximize the ultimate functional outcome in infants and children with obstetrical brachial plexus palsy.

Brachial Plexus↗
PubMed1997

Bilateral tonic-clonic epileptic seizures in non-benign familial neonatal convulsions.

We report an electroclinical pattern considered characteristic of benign familial neonatal convulsions (BFNC) in two neonates without BFNC. Both neonates were products of uncomplicated pregnancies, labor, and deliveries. The cause of the seizures was not established. There was no family history of seizures or epilepsy. Seizures started on the second and third days after birth. Ten seizures were captured by continuous video-EEG telemetry. The electroclinical events began with generalized tonic posturing coinciding with the appearance of diffuse attenuation of the EEG activity. After several seconds, bilateral clonic movements accompanied by bilateral repetitive sharp waves or spikes occurred in the EEG. One patient had normal development; the other became autistic. We conclude that the electroclinical pattern occurring in BFNC can occur in other types of neonatal seizures.

Autistic Disorder↗