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Biomedical subjects

M J Chandy

Publications and source records attributed to M J Chandy.

At least 55 records · Page 3Linked to original sources
PubMed1997

Symptomatic pneumocephalus after transsphenoidal surgery.

BACKGROUND: Symptomatic pneumocephalus after transsphenoidal surgery, though reported, is a rare phenomenon. We report three cases of pneumocephalus in a series of 300 transsphenoidal operations for sellar/suprasellar mass lesions done over the past 12 years. METHODS AND RESULTS: Three cases of symptomatic pneumocephalus occurring after transsphenoidal surgery are presented to illustrate the causative factors, methods of prevention, and management. In case 1, an intraoperative cerebrospinal fluid (CSF) leak occurred and drainage of CSF through a lumbar subarachnoid drain resulted in pneumocephalus, in spite of repair of the sellar floor. In case 2, partial excision of tumor and subsequent reduction of intracranial pressure due to a ventriculoperitoneal (VP) shunt led to pneumocephalus. In case 3, radiotherapy-induced shrinkage of a partially excised tumor resulted in pneumocephalus. The sellar floor had not been repaired in cases 2 and 3 as there was no intraoperative CSF leak and only a partial excision had been done. Conservative management failed in the two patients in whom it was tried. Repair of the sella and sphenoid sinus had to be done in all three cases. CONCLUSIONS: Repair of the sellar floor should be done after a transphenoidal approach in all cases, even when no intraoperative leak has been identified and only a partial excision of tumor has been done. Once pneumocephalus has occurred, the sellar floor and sphenoid sinus should be repaired early before reducing the intracranial pressure (ICP) by tapping ventricular air and draining or diverting CSF.

Brain Neoplasms↗
PubMed1997

Reliability of somatosensory evoked potentials in intraoperative localization of the central sulcus in patients with perirolandic mass lesions.

Patients with parenchymatous mass lesions in the perirolandic area as seen by CT or MRI are unique in that identification of the central sulcus (CS) intraoperatively is crucial in determining the surgical strategy. Somatosensory-evoked potential (SEP) responses were used under general anaesthesia for the intraoperative identification of the central sulcus (CS). Sixty-five patients with parenchymatous mass lesions were included in the study and a phase reversal in the hand area across the central sulcus was used to identify this sulcus. Based on the clinical findings the patients were classified into three groups: Group A were patients with predominant motor deficits, Group B, patients with predominant sensory deficits; and Group C were patients with gross sensory and motor deficits. This study shows that in patients with predominant motor deficits a phase reversal with good amplitude was obtained in all cases. In patients with predominant sensory deficits a phase reversal could be obtained, but their amplitudes were markedly decreased. In patients with predominant sensorimotor deficits no phase reversal could be obtained. The central sulcus could not be located accurately by somatosensory evoked potentials in these cases (group C).

Adult↗
PubMed1997

Tuberculomas presenting as isolated intrinsic brain stem masses.

We document the clinical presentation, management and outcome of histologically verified, solitary, intrinsic brain stem tuberculomas in six patients. The neurological symptoms and signs in these patients did not distinguish their lesions from other intrinsic masses of the brain stem. On contrast-enhanced computed tomography (CT), the tuberculomas appeared as ring enhancing lesions in three patients and nodular contrast enhancing lesions in the other three. Diagnosis was established on the basis of CT-guided stereotactic biopsy in all patients. All patients were treated with antituberculous drugs for 18 months. Steroid therapy of 2-8 weeks duration was also used in four patients. At a median follow-up period of 20 months (range 9-51 months), three patients were asymptomatic and the other three were functioning independently with mild disability. Although isolated, intrinsic brain stem tuberculoma is an uncommon entity, it should be suspected in patients presenting with features of an intrinsic brain stem mass and a contrast-enhancing lesion on CT. CT-guided stereotactic biopsy usually provides evidence of the inflammatory nature of the mass although an aetiological diagnosis is often elusive. Early diagnosis and appropriate therapy with antituberculous drugs and steroids usually results in an excellent or good outcome in most instances.

Adolescent↗
PubMed1997

Validation study of a central venous pressure-based protocol for the management of neurosurgical patients with hyponatremia and natriuresis.

OBJECTIVE: We had previously suggested a protocol for the management of neurosurgical patients with hyponatremia and natriuresis that was based on their volume status as determined by actual blood volume measurements. All patients in that study were found to be hypovolemic or normovolemic and responded, within 72 hours, to salt and fluid replacement. In the present study, the validity of that protocol was tested using central venous pressure as the sole measure of volume status of patients with hyponatremia and natriuresis. METHOD: Twenty-five consecutive patients (26 cases) who fulfilled the inclusion criteria typically used to diagnose the syndrome of inappropriate secretion of antidiuretic hormone were included in the study. Central venous pressure was used to classify patients as hypovolemic (< 5 cm of water), normovolemic (6-10 cm of water), or hypervolemic (> 11 cm of water). Hypovolemic patients were given fluids (50 ml/kg/d) and salt (12 g/d). Normovolemic patients were given normal fluid with 12 g of salt per day. In addition, patients with anemia (hematocrit, < 27%) were administered whole blood. The end point was a serum sodium of more than or equal to 130 mEq/L measured in two consecutive samples 12 hours apart or 72 hours after entry into the study. If the serum sodium was less than 130 mEq/L at the end of 72 hours, the clinical condition of the patient determined further management. RESULTS: Nineteen of 25 patients (26 cases) were hypovolemic, the rest were normovolemic. No patient was hypervolemic. Nineteen of 25 patients (26 cases) attained normal serum sodium values within 72 hours, and an additional 3 responded within the next 36 hours (108 h after entry into the study). One patient who was discharged on request had normalized her serum sodium a week later. Among the three nonresponders, who were severely hypovolemic, as revealed by blood volume measurement, and responded to increased fluid and salt administration. One was normovolemic and responded to increased salt administration. There were no complications related to the therapy. CONCLUSION: Hyponatremia with natriuresis in the neurosurgical setting responds to salt and fluid replacement guided by the patients' volume status as determined by the central venous pressure. This study also offers further indirect evidence to suggest that the syndrome of hyponatremia with natriuresis is most often caused by "cerebral salt wasting" rather than by the syndrome of inappropriate secretion of antidiuretic hormone.

Adolescent↗
PubMed1997

Validation of diagnostic criteria for solitary cerebral cysticercus granuloma in patients presenting with seizures.

OBJECTIVE: To evaluate a set of clinical and computed tomographic (CT) criteria (previously described by us) to predict the diagnosis of a solitary cerebral cysticercus granuloma (SCCG) at initial presentation, in patients presenting with seizures. MATERIAL AND METHODS: The diagnostic criteria were applied prospectively to patients presenting with seizures and solitary lesion on the CT scan. The clinical diagnostic criteria were as follows: seizures should be the presenting complaint; there should be no evidence of persistent raised intracranial pressure, progressive neurological deficit or an active systemic disease. The CT diagnostic criteria were: evidence of a solitary contrast enhancing lesion measuring 20 mm or less in its maximal dimension without a shift of the midline structures due to the surrounding oedema. A diagnosis of SCCG was made only when all the clinical and CT criteria were fulfilled. Over a period of 36 months, we managed 401 patients presenting with seizures and a solitary mass on the CT scan; 215 met the criteria for the diagnosis of an SCCG. RESULTS: Of the 215 patients initially diagnosed to have an SCCG, 197 were ultimately determined to have that diagnosis (true positive diagnosis) while 16 were excluded because of lack of follow-up CT assessment. Two of the 215 patients with the initial diagnosis of an SCCG subsequently had histological diagnosis of a secondary metastasis and a pyogenic abscess (false positive diagnosis). Our set of diagnostic criteria for SCCG had a sensitivity of 99.5%; specificity of 98.9%; a positive predictive value of 99%; and a negative predictive value of 99.5%. The likelihood ratios for the positive and negative tests were 92.99 and 0.005 respectively. CONCLUSIONS: Our diagnostic criteria help in not only accurately identifying an SCCG but also in differentiating it from a solitary tuberculoma and other brain masses. However, confirmation of the diagnosis of an SCCG is only obtained at follow-up evaluation and therefore careful clinical and CT re-evaluation is essential in all patients initially diagnosed to have an SCCG.

Albendazole↗
PubMed1996

Comparative study of CT and MRI in patients with seizures and a solitary cerebral cysticercus granuloma.

We hypothesized that when contrast-enhanced CT reveals a solitary cerebral cysticercus granuloma, MRI would not usually provide additional information that might assist in management. We retrospectively compared visualisation of solitary cysticercus granulomas on contrast-enhanced CT and MRI in 16 patients presenting with seizures; gadolinium (Gd) enhancement was used in 6 patients. The granuloma was delineated well on both CT and MRI in 15 patients; in one patient, in whom CT was performed with 10-mm slices, it was seen only on contrast-enhanced MRI, CT and unenhanced MRI revealing only the surrounding oedema. On CT the granuloma was seen best on thin (2-5 mm) contrast-enhanced sections (in 10 patients). On MRI, Gd-enhanced images showed the granuloma best, as a ring-enhancing lesion, in all 6 patients. In the other 10 patients, the granuloma was seen only on T2-weighted images in 8 and on both T1- and T2-weighted images in 2. On T2-weighted images a characteristic low-signal ring with a high-signal centre was seen in 12 patients. Sensitivity of the imaging techniques was: contrast-enhanced CT (5 and 10 mm slices) 93.8% (15/16); thin (2-5 mm) section contrast-enhanced CT 100% (6/6); unenhanced MRI 93.8% (15/16). MRI did not reveal additional granulomas or cysts in any patient. In patients strongly suspected to be harbouring this lesion, when 10-mm contrast-enhanced CT reveals only oedema, thin (2-5 mm) slice CT is a cost-effective alternative to MRI.

Adolescent↗
PubMed1996

Value of visual evoked potential monitoring during trans-sphenoidal pituitary surgery.

The visual outcome of 22 patients undergoing trans-sphenoidal excision of pituitary macroadenomas with intraoperative flash visual evoked potential (VEP) monitoring (Group A), was compared with a non-randomized group of 14 patients who had undergone similar operations without VEP monitoring (Group B). Tumour size, preoperative visual acuity, peripheral fields, and latencies and amplitudes of P1 and P2 were analysed to ascertain the best predictor of postoperative visual function. It was found that patients in Group A had a significantly greater improvement in field defects than those in Group B. There was no difference in postoperative improvement in visual acuity between the two groups. None of the variables analysed were good predictors of visual outcome.

Adenoma↗
PubMed1996

Melioidosis In India: the tip of the iceberg?

Diagnosis of melioidosis by the isolation of Burkholderia pseudomallei from one or more body fluid/tissue specimens of 6 Indian subjects, 5 of whom had not travelled outside India, is reported. The places of residence of these 6 and one patient previously reported, namely Tripura (2), Kerala (2), Orissa (1), Tamil Nadu (1) and Maharashtra (1) are therefore potentially endemic for melioidosis. B.pseudomallei closely resembles common contaminant Pseudomonas sp. and are easily mis-identified in microbiology laboratories. We surmise that melioidosis is underdiagnosed and underreported in India and we alert clinicians, microbiologists and public health professionals to the possibility of melioidosis being far more common than previously recognised.

Adolescent↗
PubMed1996

Changes in phospholipids and acetylcholinesterase during early phase of injury to spinal cord--an experimental study in rats.

Injury to spinal cord was produced in rats by the clip compression technique by placing the aneurysm clip extradurally for 30 seconds. The traumatised spinal segment and the adjoining upper segment were used for biochemical estimations. Motor function of the injured rats was evaluated using the inclined plane. Phospholipid phosphorus values were significantly decreased in the injured spinal segment at 24 hrs. AchE activity was also decreased in the traumatised segment one week after injury. Dexamethasone and verapamil reversed the changes in AchE activity at the end of one week. At the one week assessment period, aneurysm clipped rats showed a decrease in the maximum angle in the inclined plane. Dexamethasone and verapamil treated rats showed improvement in the neurologic function, neurologic recovery was better in the dexamethasone treated group.

Acetylcholinesterase↗
PubMed1995

Desmoplastic low grade astrocytoma: a case report and review of literature.

A 7-year-old girl presented with focal seizures without symptoms of raised intracranial tension. Routine histological, immunocytochemical and ultrastructural methods revealed a desmoplastic low grade cerebral astrocytoma. Follow up for 2 years after biopsy did not show recruitment of neurological symptoms or signs. Biphasic tumours containing glial and mesenchymal elements have been described in the literature under various diagnostic headings. As the histologically benign variants of mixed glial and mesenchymal tumours appear to have a good prognosis, identification of these as separate entities seems imperative. With a review of literature we propose a pathological classification of mixed glial and mesenchymal tumours.

Arachnoid Cysts↗
PubMed1995

Effect of intrathecal saline injection and Valsalva maneuver on cerebral perfusion pressure during transsphenoidal surgery for pituitary macroadenoma.

Cerebrospinal fluid pressure (CSFP) was monitored through a lumbar intrathecal catheter in 32 patients undergoing transsphenoidal excision of pituitary macroadenomas. In the first 20 patients, standardized intermittent Valsalva maneuvers were followed by intrathecal saline injections in 2.5-ml increments. Their effects on CSFP, mean arterial pressure (MAP), and therefore, cerebral perfusion pressure (CPP) were compared. The increase in CSFP produced by one Valsalva maneuver (4 +/- 2 mm Hg) was similar to that produced by a single increment of intrathecal saline (4 +/- 2 mm Hg), but the effect of saline was more sustained. With Valsalva maneuvers, the maximum CSFP produced was 13 +/- 4 mm Hg, and the CPP decreased to 50 +/- 14 mm Hg, whereas with saline, the maximum CSFP was 25 +/- 7 mm Hg, and the CPP decreased to 59 +/- 13 mm Hg. Because the increase in CSFP was greater and better sustained with intrathecal saline, Valsalva maneuvers were omitted in the next 12 patients. Peroperative data, including surgical conditions, and post-operative morbidity, with special reference to low-pressure headache and meningeal infection, were analyzed in all 32 patients. Operative conditions produced with intrathecal saline were judged excellent or good in 75% of patients. However, because this technique can decrease the CPP excessively, we recommend that it be used only with continuous CSFP monitoring.

Adenoma↗
PubMed1995

Clinicoradiological and pathological correlations in patients with solitary cysticercus granuloma and epilepsy: focus on presence of the parasite and oedema formation.

A study of the clinical, radiological, and pathological correlations in 43 patients with solitary cysticercus granuloma and epilepsy focused on factors that might help in predicting the presence of the parasite in the granuloma and those that might influence the formation of oedema around the granuloma. The duration of symptoms (< six months and > or = six months) and CT morphology of the granuloma (ring and disc, type A; nodular lesion, type B) were studied as factors that could possibly predict the presence of the parasite in the granuloma. The influence of sex of the patient and the presence of a neutrophilic response in the granuloma on the intensity of oedema around the lesion as seen on CT was also studied. The pathological features were studied in the excised granulomas. The intact or degenerated form of the cysticercus was evident in 22 of 43 specimens. Neither the duration of seizures (P = 0.17) nor the type of lesion on CT (P = 0.16) was predictive of the presence of the parasite in the granuloma. The sex of the patient (P = 0.51) and the neutrophilic response in the specimen (P = 0.73) did not correlate with the degree of oedema on CT indicating that neither of these host factors was a major determinant of oedema production. The findings point to the varied and unpredictable natural history of solitary cysticercus granulomas and the complex nature of host-parasite interactions in individual patients. The inability to predict the presence of the parasite in the granuloma on the basis of the clinical or radiological features precludes a selection of patients with such lesions for cysticidal drug treatment.

Adolescent↗
PubMed1995

Computerized tomography-guided stereotactic surgery for brainstem masses: a risk-benefit analysis in 71 patients.

The benefits of the use of computerized tomography (CT)-guided stereotactic surgical techniques for the management of intrinsic brainstem masses diagnosed from clinical evaluation and imaging studies were evaluated vis-à-vis the risks involved in 71 consecutive patients. Seventy-two procedures were performed. The masses were diffuse, involving two or three contiguous brainstem segments, in 60 patients and focal in 11 patients. On the CT scans, 25 patients had hypodense nonenhancing masses, two had isodense nonenhancing masses, 19 had ring-enhancing masses, and 25 had heterogeneously enhancing masses. A positive biopsy was obtained in 68 of 69 patients (98.5%) undergoing a biopsy procedure. In nine patients (12.6%) with suspected malignant masses a benign pathology was diagnosed (four tuberculomas, two epidermoid cysts, one pyogenic abscess, one epidermal cyst, and one case of encephalitis). Additionally, fluid from cystic masses could be aspirated in eight cases, providing benefit in six (four patients had benign lesions and two had neoplastic lesions). Thereby, a total of 13 patients (18.3%) were deemed to have benefited from the surgery (two patients were included in both categories). Patients with focal masses and ring-enhancing masses had the highest proportion of benign lesions (60% and 36.8%, respectively) and therefore derived the most benefit from histological verification. There was no procedure-related mortality. One patient (1.4%) suffered permanent morbidity and four others (5.6%) had transient worsening attributable to the procedure. The authors conclude that CT-guided stereotactic surgery of the brainstem is safe and reliable. Histological verification of all enhancing (especially ring-enhancing) and focal brainstem masses should be undertaken to identify patients with benign nonneoplastic lesions. Selected patients with diffuse hypodense nonenhancing masses with atypical clinical or imaging features may also benefit from stereotactic biopsy. Even in these patients the lack of enhancement on a contrast-enhanced magnetic resonance image, rather than the diffuse location of the tumor alone, should form the basis for diagnosing a malignant glioma. The main value of stereotactic surgery lies in the identification of benign masses in a significant proportion of patients with intrinsic brainstem masses and in providing a rapid and safe method for evacuation of the contents of cystic masses.

Adolescent↗
PubMed1994

Management of neurosurgical patients with hyponatremia and natriuresis.

The main objective of our study was to evolve a practical management protocol for neurosurgical patients with hyponatremia and natriuresis, based on their blood volume status and hematocrit. Twenty-one patients with hyponatremia and natriuresis and 3 control patients were studied. Patients with hyponatremia were categorized on the basis of their hematocrit, central venous pressure, and total blood volume. Group A consisted of patients with hypovolemia and anemia (16 patients); Group B patients had hypovolemia but no anemia (5 patients); Group C included those with hypervolemia (0 patients). Patients in Groups A and B received isotonic saline (> 50 ml/kg/d) and oral salt (12 g/d). Additionally, those in Group A were transfused with 500 ml of whole blood. The end points in the study were 72 hours after entry or two consecutive serum sodium values of > 130 mEq/L, whichever was earlier. Hyponatremia was corrected in all the patients within 72 hours (1 patient, < 24 h; 13 patients, < 48 h; and 7 patients, < 72 h). We conclude that most neurosurgical patients with hyponatremia and natriuresis have hypovolemia, with or without anemia. Fluid and salt replacement and a blood transfusion rather than fluid restriction often results in the correction of the hyponatremia. Our findings offer indirect evidence to support the hypothesis that in most of these patients, hyponatremia is caused by cerebral salt wasting syndrome, rather than the syndrome of inappropriate secretion of antidiuretic hormone.

Adolescent↗