Biomedical subjects

Elliott Vichinsky

Publications and source records attributed to Elliott Vichinsky.

27 records · Page 2Linked to original sources

PubMed2003

Mycoplasma disease and acute chest syndrome in sickle cell disease.

BACKGROUND: Acute chest syndrome (ACS) is the leading cause of hospitalization, morbidity, and mortality in patients with sickle cell disease. Radiographic and clinical findings in ACS resemble pneumonia; however, etiologies other than infectious pathogens have been implicated, including pulmonary fat embolism (PFE) and infarction of segments of the pulmonary vasculature. The National Acute Chest Syndrome Study Group was designed to identify the etiologic agents and clinical outcomes associated with this syndrome. METHODS: Data were analyzed from the prospective study of 671 episodes of ACS in 538 patients with sickle cell anemia. ACS was defined as a new pulmonary infiltrate involving at least 1 complete segment of the lung, excluding atelectasis. In addition, the patients had to have chest pain, fever >38.5C, tachypnea, wheezing, or cough. Samples of blood and deep sputum were analyzed for evidence of bacteria, viruses, and PFE. Mycoplasma pneumoniae infection was determined by analysis of paired serologies. Detailed information on patient characteristics, presenting signs and symptoms, treatment, and clinical outcome were collected. RESULTS: Fifty-one (9%) of 598 episodes of ACS had serologic evidence of M pneumoniae infection. Twelve percent of the 112 episodes of ACS occurring in patients younger than 5 years were associated with M pneumoniae infection. At the time of diagnosis, 98% of all patients with M pneumoniae infection had fever, 78% had a cough, and 51% were tachypneic. More than 50% developed multilobar infiltrates and effusions, 82% were transfused, and 6% required assisted ventilation. The average hospital stay was 10 days. Evidence of PFE with M pneumoniae infection was seen in 5 (20%) of 25 patients with adequate deep respiratory samples for the PFE assay. M pneumoniae and Chlamydia pneumoniae was found in 16% of patients with diagnostic studies for C pneumoniae. Mycoplasma hominis was cultured in 10 (2%) of 555 episodes of ACS and occurred more frequently in older patients, but the presenting symptoms and clinical course was similar to those with M pneumoniae. CONCLUSIONS: M pneumoniae is commonly associated with the ACS in patients with sickle cell anemia and occurs in very young children. M hominis should be considered in the differential diagnosis of ACS. Aggressive treatment with broad-spectrum antibiotics, including 1 from the macrolide class, is recommended for all patients as well as bronchodilator therapy, early transfusion, and respiratory support when clinically indicated.

Acute Disease↗

PubMed2002

Distinct HLA associations by stroke subtype in children with sickle cell anemia.

Children with sickle cell anemia (SCA) carry a 200-fold increased risk for cerebral infarction. Stroke can be the result of small-vessel (SV) or large-vessel (LV) disease. However, it is unknown whether these subtypes result from the same pathophysiologic processes. Complete HLA genotyping was performed on 231 eligible children previously enrolled in the Cooperative Study of Sickle Cell Disease (CSSCD). Cerebral infarction on magnetic resonance imaging (MRI) was documented in 71 patients, and 160 patients had negative findings on MRI. Based on MRI/magnetic resonance angiography (MRA) findings, infarct size, and location, 36 patients were classified as having LV stroke and 35 as having SV stroke. When comparing the total MRI+ group with the MRI- group, HLA DPB1*0401 was associated with increased stroke risk (P =.01), whereas DPB1*1701 (P =.02) conferred protection from stroke. These DPB1 associations with stroke were attributed to the SV stroke group, in whom DPB1*0401 was associated with susceptibility (P =.003) and DPB1*1701 with protection from stroke (P =.06). In the LV stroke subgroup, HLA-A*0102 (P =.02) and -A*2612 (P =.007) conferred susceptibility, whereas -A*3301(P =.04) protected from stroke. These results suggest that specific HLA alleles influence stroke risk and appear to contribute differently to SV and LV stroke subtypes. The distinct HLA associations with SV and LV stroke suggest that different pathologic processes may be involved in the development of stroke in children with SCA. If these results are confirmed in a larger study, HLA type may serve as a useful marker for the early identification of SCA patients at high risk for stroke.

Adolescent↗

PubMed2002

New therapies in sickle cell disease.

CONTEXT: New therapies have evolved from our improved understanding of the biology of sickle cell disease (SCD) and the availability of a useful transgenic animal model. Several therapeutic options are available that interrupt the sickling process at various key pathways. Nitric oxide (NO)is a critical factor in the pathophysiology of SCD and is a promising antisickling agent with vasodilation properties. NO regulates blood vessel tone, endothelial adhesion, and the severity of ischaemia-reperfusion injury and anaemia in SCD. Although NO is difficult to administer, its precursor, L-arginine, is an oral supplement. STARTING POINT: J R Romero and colleagues recently demonstrated in sickle transgenic mice that oral arginine supplementation induced NO production and reduced red-cell density by inhibiting the Gardos channel, which modulates cell hydration and polymerisation of haemoglobin S (Blood 2002; 99:1103-08). Haemoglobinopathies can be cured by stem-cell transplantation. This therapy is now accepted treatment in symptomatic children. However, most patients lack a genotypically identical family donor. G La Nasa and colleagues demonstrated unrelated-donor stem-cell transplantation may give similar results to related-donor stem-cell transplantation when extended phenotypic matching is used (Blood 2002; 99: 4350-56). This pilot study offers the possibility of cure to patients without a family donor. WHERE NEXT: Although potential opportunities to prevent morbidity in SCD through new therapies are exciting, most patients do not have access to standard multidisciplinary specialty care. Patients require both.

Anemia, Sickle Cell↗

PubMed2002

Central venous catheter complications in sickle cell disease.

A review of patients with sickle cell disease (SCD) and central venous catheters (CVCs) was performed to evaluate the frequency of catheter complications (infections, thrombotic events, and premature CVC removal. Fifteen evaluable patients were identified during our review of a 7.5-year period. The median age was 18 years (range, 1.5-30 years); 14 were African American, and 1 was Latino; 5 were male, and 10 were female. Forty-one CVCs were placed (36 Mediport and 5 Broviac catheters) for a total of 12,120 CVC days. We observed a median of 2 CVCs per patient (range, 1-8 CVCs per patient) with 67 discrete episodes of CVC-associated infection (range, 0-18 per patient) involving 10 patients. The rate of CVC-associated infection for patients with SCD at our institution was 5.5 infections per 1,000 CVC days; this rate was significantly higher than the rate of CVC-associated infection in our patients with cancer (P < 0.001). We also determined that the rate of CVC-associated thrombosis was 0.99 events per 1,000 CVC days and involved 33% of the patients with SCD; the rate of premature CVC removal was 3.15 per 1,000 CVC days, and 78% of CVCs were removed prematurely. We conclude that patients with SCD are at high risk for CVC-related complications, and improved care and close monitoring of CVCs should be encouraged to decrease morbidity in these chronically ill patients.

Adolescent↗

PubMed2002

Assessment of sickle cell pain in children and young adults using the adolescent pediatric pain tool.

The objectives of this study were to describe and compare the characteristics of pain experienced by children and young adults with sickle cell disease (SCD) in inpatient and outpatient settings. The Adolescent Pediatric Pain Tool (APPT), a multidimensional self-report pain assessment, was completed by African American children and young adults (mean age 15.39 +/- 4.32) with SCD during a clinic visit (n = 52), day hospital visit (n = 29), or during the first 24 hours of an inpatient stay (n = 72). Multiple linear regression revealed that pain intensity, number of body areas with pain, and the quality of pain were related to age, sex, and care setting. Pain intensity, location, and quality were of greater magnitude than previous reports of early postoperative pain in children. Examining the specific dimensions of pain intensity, location, and quality and the influencing factors of age, sex, and care setting may lead to more effective treatments for SCD pain.

Adolescent↗

PubMed2002

Using quality improvement strategies to enhance pediatric pain assessment.

OBJECTIVE: To evaluate the impact of a quality improvement approach to implementing developmentally appropriate pain assessment guidelines for pediatric inpatients. Patient and staff satisfaction with pain assessment and management, and staff documentation were evaluated one year following the implementation of the revised pain assessment guidelines. DESIGN: Quasi-experimental design. SETTING: The pediatric hematology/oncology unit of a regional children's hospital. Study participants. A convenience sample of 36 children and 68 staff at time 1 (TI) and 49 children and 82 staff at time 2 (T2). INTERVENTIONS: Staff were educated on the use of pediatric pain assessment tools and a standardized pain assessment protocol was put into practice. Children or their primary caregivers were interviewed, using a questionnaire modified from the American Pain Society quality assurance guidelines, regarding their experiences with pain assessment and management on the unit at T1, just prior to the staff education, and one year later at T2. Multidisciplinary unit staff completed a parallel questionnaire at T1 and T2. MAIN OUTCOME MEASURES: Patient and staff satisfaction with pain assessment and management, and chart audit of compliance with pain assessment documentation. RESULTS: Patients, family members, and staff reported increased pain assessment, improved staff responsiveness to patients' pain and greater satisfaction with assessment tools between TI and T2. Increased compliance with the assessment guidelines was confirmed by chart audit. CONCLUSIONS: Improved pain assessment and management practices with resultant increase in patient and staff satisfaction can be achieved and sustained over time using quality improvement strategies.

Adolescent↗

PubMed2002

Longitudinal changes in ferritin during chronic transfusion: a report from the Stroke Prevention Trial in Sickle Cell Anemia (STOP).

PURPOSE: Chronic red cell transfusion has been used for prevention of recurrent stroke in patients with sickle cell disease for three decades, and its effectiveness in primary prevention was recently shown. Iron overload, the inevitable result of chronic transfusion, is commonly monitored with serum ferritin concentration. PATIENTS AND METHODS: Sixty-one patients at high risk for stroke received chronic transfusion in a clinical trial of stroke prevention. A serum ferritin level of less than 500 ng/mL was required for study entry. Ferritin levels were obtained quarterly. Fifty patients who had four or more ferritin measurements were included in this analysis. Transfusions were administered as exchange or simple, with washed, reconstituted, or packed red blood cells, at the discretion of the site investigator. RESULTS: Serum ferritin levels increased linearly with cumulative transfusion volume during the first four ferritin measurements, but the rate of increase varied widely among patients. Rates of increase varied similarly among 23 patients who received exclusively simple transfusion with packed red cells and in five patients who received exchange transfusions. Thirty-two patients received a total transfusion volume of more than 250 mL/kg. Ferritin continued to increase linearly after the first four measurements in 14, but the remaining 18 experienced a plateau before the level reached 3,000 ng/mL. Six of those with a linear increase never reached a ferritin level of 3,000 ng/dL. CONCLUSIONS: There was strong intrapatient correlation between serum ferritin levels and volume transfused but wide interpatient variability early during chronic transfusion therapy. Intrapatient correlation declined at transfusion volumes of more than 250 mL/kg. Direct iron store assessment is needed to determine the clinical significance of serum ferritin variability.

Adolescent↗

PubMed2002

Pancytopenia induced by hypothermia.

Hypothermia has been demonstrated to induce pancytopenia in animals, but whether this association exists in humans is unknown. The authors report the case of an 8-year-old girl in whom hypothermia (temperature 33 degrees C-35 degrees C) is the cause of pancytopenia. The patient developed thermoregulatory dysfunction subsequent to surgical resection of a craniopharyngioma. Her recurrent cytopenias could not be explained by any etiology except chronic hypothermia. The pancytopenia improved upon rewarming the patient to a temperature of 36 degrees C. This association between hypothermia and pancytopenia has rarely been reported in humans and may be underdiagnosed especially in cases of transient or milder presentations. The authors recommend careful hematologic monitoring of patients with thermoregulatory dysfunction.

Adrenal Insufficiency↗

PubMed2002

Novel therapeutic approaches in sickle cell disease.

In this update, selected clinical features of sickle cell disease and their management are reviewed. In addition, the current status of interventions that have curative potential for sickle cell disease is discussed, with particular attention focused on indications, methodology, recent results, and challenges to wider clinical application. In Section I, Dr. Nienhuis describes recent improvements in vector technology, safety, and replacement gene expression that are creating the potential for clinical application of this technology. In Section II, Dr. Vichinsky reviews our current understanding of the pathophysiology and treatment of pulmonary injury in sickle cell disease. The acute and chronic pulmonary complications of sickle cell disease, modulators and predictors of severity, and conventional and novel treatment of these complications are discussed. In Section III, Dr. Walters reviews the current status of hematopoietic cell transplantation for sickle cell disease. Newer efforts to expand its availability by identifying alternate sources of stem cells and by reducing the toxicity of transplantation are discussed.

Anemia, Sickle Cell↗