Pooling in chronic orthostatic intolerance: arterial vasoconstrictive but not venous compliance defects.
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BACKGROUND: Orthostatic intolerance is characterized by postural tachycardia syndrome (POTS) with exaggerated tachycardia, orthostatic symptoms, and "pooling" (which comprises acrocyanosis and dependent edema when upright). My colleagues and I tested the hypothesis that pooling results from increased venous compliance in POTS patients. METHODS AND RESULTS: Fifteen patients aged 13 to 19 years were compared with 11 healthy, age-matched controls. The POTS group was divided into patients with high venous pressure (P(v)>20 mm Hg) and normal P(v) on the basis of resting supine P(v) obtained in previous work. Subjects were studied using strain gauge plethysmography to measure blood flow, P(v), and the venous compliance volume-pressure relation while supine and during incremental head-up tilt testing at -10 degrees, 0 degrees, 20 degrees, and 35 degrees. Volume-pressure relations of controls and POTS patients with normal P(v) and high P(v) were not different and were unchanged by orthostasis. Supine leg peripheral resistance was greater than control resistance in patients with high P(v) (54+/-9 versus 30+/-6 mm Hg x mL(-1) x 100 mL(-1) x min(-1)) and less than control resistance in patients with normal P(v) (17+/-2 mm Hg x mL(-1) x 100 mL(-1) x min(-1)). On upright tilt, resistance decreased in high P(v) to approximate resistance in normal P(v). Resistance in controls increased throughout tilt. Leg P(v) increased in patients with normal P(v) and in controls but remained unchanged in the high P(v) group. CONCLUSIONS: The findings suggest that pooling in POTS is due to blunted arterial vasoconstriction, which produces passive redistribution of blood within peripheral venous capacitance beds. Venous compliance in POTS is similar to that in control subjects. (+info)
The origin of hydrogen sulfide in a newborn with sulfhaemoglobin induced cyanosis.
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This report investigated the origin of H(2)S in a newborn boy with sulfhaemoglobin induced cyanosis, who died because of multiple organ failure. Frozen material was collected and studied after death. The results suggest that enzymes had been released from deteriorating organs into the blood and abdominal fluid, and that the reaction of one of these enzymes with sulfur containing amino acids might have resulted in increased H(2)S concentrations. It is hypothesised that this release of enzymes resulted from a haemolysin produced by an invasive haemolytic Escherichia coli that was found in the blood and organs of this patient. (+info)
Methemoglobinemia following unintentional ingestion of sodium nitrite--New York, 2002.
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Methemoglobinemia is an unusual and potentially fatal condition in which hemoglobin is oxidized to methemoglobin and loses its ability to bind and transport oxygen. The most common cause of methemoglobinemia is the ingestion or inhalation of oxidizing agents such as nitrates or nitrites (e.g., sodium nitrite, which is used commonly as a preservative in curing meats and fish). This report summarizes the investigation of an incident of methemoglobinemia in five members of a household in New York who became ill after eating a meal seasoned with a white crystalline substance from a plastic bag labeled "Refined Iodized Table Salt" (Figure). The findings underscore the need for proper storage of hazardous materials to avoid unintentional ingestion and the importance of collaboration by multiple agencies to address a potential public health emergency. (+info)
Ebstein's anomaly: one and a half ventricular repair.
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Patients with Ebstein's anomaly can present after childhood or adolescence with cyanosis, arrhythmias, severe right ventricular dysfunction and frequently with left ventricular dysfunction secondary to the prolonged cyanosis and to the right ventricular interference. At this point conventional repair is accompanied by elevated mortality and morbidity and poor functional results. We report our experience with three patients (8, 16 and 35 years of age) with Ebstein's anomaly, very dilated right atrium, severe tricuspid valve regurgitation (4/4), bi-directional shunt through an atrial septal defect and reduced left ventricular function (mean ejection fraction = 58%, mean shortening fraction = 25%). All underwent one and a half ventricular repair consisting of closure of the atrial septal defect, tricuspid repair with reduction of the atrialised portion of the right ventricle and end-to-side anastomosis of the superior vena cava to the right pulmonary artery. All patients survived, with a mean follow-up of 33 months. In all there was complete regression of the cyanosis and of the signs of heart failure. Postoperative echocardiography showed reduced degree of tricuspid regurgitation (2/4) and improvement of the left ventricular function (mean ejection fraction = 77%, mean shortening fraction = 40%). In patients with Ebstein's anomaly referred late for surgery with severely compromised right ventricular function or even with reduced biventricular function, the presence of a relatively hypoplastic and/or malfunctioning right ventricular chamber inadequate to sustain the entire systemic venous return but capable of managing part of the systemic venous return, permits a one and a half ventricular repair with good functional results. (+info)
Acrocyanosis as a side effect of tricyclic antidepressants: a case report.
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Acrocyanosis is probably the most unusual side effect of tricyclic antidepressant drugs. In this paper, we report a 10-year-old boy with primary enuresis nocturna and attention deficit hyperactivity disorder who developed two episodes of acrocyanosis, the first of which was after imipramine treatment and the second after desipramine usage. We also review the possible pathogenesis of acrocyanosis. We suggest that physicians should be aware of this rare side effect of tricyclic antidepressants. (+info)
Asymmetric crying facies: the cardiofacial syndrome.
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A 5 1/2 month old female child presented with cyanosis and recurrent respiratory infection. Asymmetric facies was noticed on crying. On investigation an ostium secundum atrial septal defect with right partial anomalous pulmonary venous connection and severe pulmonary hypertension was detected. The association of asymmetric crying facies with congenital cardiac anomalies, known as cardiofacial syndrome, is presented here to highlight the use of this clinical sign as a marker to congenital anomalies. (+info)
Transcriptional regulation of left ventricular beta-adrenergic receptors during chronic hypoxia.
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beta-Adrenergic receptor downregulation is the end result of cellular adaptation to prolonged agonist exposure. The factors mediating receptor downregulation include receptor phosphorylation, receptor movement from the plasma membrane to intracellular sites, and alterations in nascent receptor synthesis. We have previously demonstrated a downregulation of the left ventricular beta-receptor during chronic hypoxia in vivo. To determine the mechanism of this downregulation, we produced chronic hypoxia in seven newborn lambs by creating right ventricular outflow obstruction and an atrial septal defect. Oxygen saturation was reduced to 65-74% for 2 weeks. Six lambs served as normoxic controls. Sarcolemmal membrane and cytosolic fractions were prepared from left ventricular free wall samples. beta-Receptor density in each fraction was determined with the radioligand [125I]iodocyanopindolol. Steady-state levels of beta-receptor mRNA were determined by Northern blot analysis using a beta 1-adrenergic receptor cDNA probe. During chronic hypoxia, left ventricular membrane beta-adrenergic receptor density decreased by 55% (153 +/- 28 fmol/mg for hypoxic lambs versus 342 +/- 79 fmol/mg for control lambs, p < 0.05). There was no corresponding increase in beta-receptor density in the cytosolic fraction (23 +/- 3 fmol/mg for hypoxic lambs versus 33 +/- 9 fmol/mg for control lambs, p = NS), nor was there a significant change in the ratio of beta 1-receptor/beta 2-receptor subtypes as assessed by radioligand binding (beta 1 subtype, 84.1 +/- 10.1% for hypoxic lambs versus 93.2 +/- 8.8% for control lambs; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS) (+info)
Risk factors for brain abscess in patients with congenital cyanotic heart disease.
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Brain abscess is a serious complication of congenital cyanotic heart disease. We retrospectively evaluated the risk factors for brain abscess in 21 such patients treated between 1975 and 1990 in comparison with a control group. The mean arterial oxygen saturation, arterial partial pressure of O2, arterial blood oxygen content, and base excess in patients with brain abscess were significantly lower than in the control patients. The mean arterial partial pressure of CO2, pH, hematocrit, hemoglobin, and red blood cell content in patients with brain abscess were not significantly different. Patients with congenital cyanotic heart disease may develop minute encephalomalacia due to severe hypoxemia and increased blood viscosity resulting from compensatory polycythemia. The increased blood viscosity and reduced blood flow in the microcirculation may induce cerebral thrombosis or exaggerate minute encephalomalacia during dehydration or cardiac dysfunction, and shunted blood containing infectious organisms at such sites may be followed by focal cerebritis. (+info)