Vasopressin and thirst in patients with posterior pituitary ectopia and hypopituitarism

OBJECTIVE: Partial diabetes insipidus has been documented in patients with congenital hypopituitarism and posterior pituitary ectopia, some cases being clinically silent except for enuresis. The objective of our study was to evaluate vasopressin (AVP) secretion and thirst appreciation in hypopituitary patients with posterior pituitary ectopia. PATIENTS: Twelve males and three females, aged between 13 and 38 years (median 19 years). Eleven had multiple pituitary deficiencies, adequately replaced at the time of the study, and four were only growth hormone deficient. None of the patients suffered from polyuria, polydipsia or nocturnal enuresis. We tested the patients with a 5% NaCl infusion. Five patients with abnormal vasopressin production were also tested with nitroprusside, which affects baroceptor vasopressin secretion. RESULTS: We found that only two out of 12 patients had normal AVP secretion. Thirst assessment showed severe hypodipsia in one patient, hyperdipsia in three out of 15 and more subtle abnormalities in two out of 15 patients. Concordance was found between osmotically and baroceptor-stimulated vasopressin. CONCLUSIONS: Patients with posterior pituitary ectopia showed a high prevalence of subclinical subnormal vasopressin response to the osmolar stimulus and moreover an impairment of thirst appreciation. Our data on nonosmotically stimulated AVP release suggest the existence of a damage in the hypothalamic vasopressin secreting centres.     

Impact of intravascular thrombosis on failure of radial arterial catheters in critically ill patients: a nested case-control study

Purpose

The patency of arterial catheters is essential for reliable invasive blood pressure monitoring. We sought to determine whether radial catheter failures were associated with intravascular thrombosis in critically ill adult patients.

Methods

This unmatched case-control study was conducted within a prospective cohort of patients admitted to an intensive care unit. The arterial catheter failure was the main outcome, which identified cases. Controls were patients with patent catheter until removal or 28 days of follow-up. The prevalence of intravascular thrombosis in cases and controls was determined by ultrasonography of the cannulated radial artery. Assessors were blinded to clinical findings. Failing catheters were removed and examined microscopically.

Results

Catheter failures occurred in 25.5% of 200 patients during 584 catheter-days (incidence rate, 87/1000 catheter-days). The median patency duration was 13.1 days. An intravascular thrombosis located in front of the catheter tip was diagnosed in 42 of 50 cases (84.0%) and 24 of 139 controls (17.3%). In multivariable logistic regression analysis, the probability of catheter failure was higher in patients with intravascular thrombosis [odds ratio (OR), 36.52; 95% confidence interval (CI), 12.86–103.74] and females (OR, 3.45; 95% CI 1.32–9.05), increased proportionally to arterial blood sampling frequency (OR, 1.20; 95% CI 1.04–1.38), and decreased in thrombocytopenia (OR, 0.28; 95% CI 0.10–0.78). After removal, 15.7% of failing catheters had some luminal fibrin deposits, but none were occluded.

Conclusions

Most failing radial arterial catheters had no luminal obstruction, but were associated with an intravascular thrombosis. Among predictive factors, arterial blood sampling frequency is the most susceptible to intervention.

     

Acute systemic, splanchnic and renal haemodynamic changes induced by molecular adsorbent recirculating system (MARS) treatment in patients with end-stage cirrhosis

AIM: To evaluate the acute effect of treatment with the molecular adsorbent recirculating system (MARS) on splanchnic, renal and systemic haemodynamics in patients with end-stage cirrhosis. METHODS: Twelve patients with end-stage cirrhosis, undergoing MARS treatment, were enrolled. The following haemodynamic parameters were measured by means of Doppler ultrasonography and thoracic electrical bioimpedance, before and after each session: portal velocity, renal and splenic resistance indices, cardiac output, cardiac stroke volume, heart rate, mean arterial pressure, systemic vascular resistance. RESULTS: Median portal velocity increased significantly after treatment (23.7 vs. 20.3 cm/s, P < 0.05) while renal resistance index (0.72 vs. 0.75, P < 0.05) and splenic resistance index (0.60 vs. 0.65, P < 0.05) decreased significantly. Mean arterial pressure (83 vs. 81 mmHg, P < 0.05) and vascular resistance (899 vs. 749 dyne. s/cm5, P < 0.05) increased significantly, while cardiac output and stroke volume showed no significant changes. CONCLUSIONS: Data emerging from this investigation suggest that MARS treatment improves significantly various haemodynamic alterations in cirrhotic patients in the short term. The observed decrease in renal vascular resistance and improvement in splenic resistance index, a parameter related to portal resistance, which leads us to hypothesize that these haemodynamic effects are probably mediated by clearance of vasoactive substances during MARS treatment.     

Diagnostic value of a negative single complete compression ultrasound of the lower limbs to exclude the diagnosis of deep venous thrombosis in pregnant or postpartum women: a retrospective hospital-based study

OBJECTIVE: We aimed at determining whether a negative single complete compression ultrasonography (CUS) of the lower limbs veins is a safe and accurate diagnostic method to rule out the diagnosis of deep venous thrombosis in pregnant and early postpartum women. DESIGN: Hospital-based retrospective study. SETTING: The gynaecology and vascular ultrasound units of three general hospitals in western France. PATIENTS: We identified from the hospitals databases all pregnant or up to three months postpartum women who underwent CUS for a suspicion of deep venous thrombosis between January 2002 and December 2004. METHODS: Questionnaires were sent to all women with a negative CUS. Their medical records were also checked. MAIN OUTCOME MEASURES: We assessed the three-month thromboembolic risk and its 95% percent confidence interval in women left untreated on the basis of a negative single complete CUS of the lower limbs. RESULTS: During the study period, 162 pregnant or postpartum women underwent CUS for a suspicion of deep venous thrombosis. It was positive in 44 (27%). The 118 women who had a negative CUS were sent the questionnaire. Information about the three-month follow-up was found for 107 patients (91%). None of them experienced a thromboembolic event during follow-up: 0.0% (95% CI: 0.0-3.6). CONCLUSIONS: Single complete CUS of lower limbs veins appears to be a safe method to rule out the diagnosis of deep venous thrombosis in pregnant or early postpartum women. This has to be confirmed by a prospective management study with a formal follow-up.     

Parkinson's disease, chronic hydrocarbon exposure and striatal neuronal damage: a 1-H MRS study

Several patients with Parkinson' s disease (PD) reveal an history of chronic exposure to hydrocarbon-solvents. Chronic exposure to hydrocarbon-solvents has been proposed as a risk factor for more severe forms of PD with earlier onset of symptoms and reduced response to dopaminergic therapy. A direct correlation between disease severity and exposure degree has been previously shown. Seven exposed PD patients (two with low degree exposure and five with high degree exposure), 10 unexposed PD patients matched for sex, age and Hoehn and Yahr scale (=3 in the "on" phase), and 10 unexposed PD patients matched for sex, age and l-dopa daily intake instead of disease severity (Hoehn and Yahr scale=3.5 in the "on" phase) were studied. Twenty normal subjects without previous exposure to hydrocarbon-solvents and matched for age and sex with HPD patients were studied for comparison. The purpose of the study was to assess neuronal degeneration in the striatum of exposed vs unexposed PD patients. The authors investigated whether neuronal damage/loss was detectable in the lentiform nucleus measuring N-acetylaspartate (NAA) levels by 1-H MRS. Multiple single voxel MRS water-suppressed spectra were obtained also from the white matter and the occipital lobe. NAA was normal in the lentiform nucleus of patients with low exposure as well as in patients with no exposure whereas it was decreased in PD patients with high degree exposure. White matter and occipital lobe NAA content was normal both in exposed and unexposed PD patients. Clinical expression is more severe in PD patients with previous high degree solvent exposure because of the associated post-synaptic damage of the nigro-striatal pathway.