ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Diamond-Blackfan Anemia (DBA) is a rare, congenital hypoplastic anemia often diagnosed early in infancy. A moderate to severe aregenerative anemia is found in association with erythroblastopenia in an otherwise normocellular bone marrow. In 40% of these infants with DBA, diverse developmental abnormalities are also noted. A majority of patients with DBA respond to steroid therapy. Recent molecular studies have identified mutations in the gene encoding the ribosomal protein RPS19 on chromosome 19 in 25% of patients with DBA. In another subset of patients, linkage analysis has identified another locus on chromosome 8p in association with DBA. There are, however, other cases of DBA that are linked neither to the RPS19 gene nor to the locus on 8p, implying the involvement of yet-to-be-defined genetic defects in the cause of DBA. The pathogenesis of DBA is still to be fully defined and it is anticipated that further molecular studies will lead to a better understanding of this complex disease.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The healthy fetus has a platelet count of greater than 150 × 109/L by the second trimester of pregnancy and only 2% of term infants are thrombocytopenic at birth. Severe thrombocytopenia (platelets < 50 × 109/L) occurs in fewer than three per 1000 term infants, the most important cause being alloimmune thrombocytopenia. In contrast, in infants admitted to neonatal intensive care units, thrombocytopenia develops in 25% and in up to half of sick preterm infants. Recent evidence shows that these infants mostly have evidence of underlying impaired fetal megakaryocytopoiesis and platelet production following pregnancy complications characterized by placental insufficiency or fetal hypoxia. The mechanism of this is unknown. However, many neonatal complications exacerbate this thrombocytopenic potential and 20% of thrombocytopenias in neonatal intensive care unit patients are severe. Evidence-based guidelines for platelet transfusion therapy in these patients are yet to be defined, but as platelet underproduction underlies most neonatal thrombocytopenias, recombinant hemopoietic growth factors, including thrombopoietin and interkeukin-11, may be useful future therapies.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Patients who are homozygous for the sickle hemoglobin mutation can present with remarkably different clinical courses, varying from death in childhood, to recurrent painful vasoocclusive crises and multiple organ damage in adults, to being relatively well even until old age. Increasing numbers of genetic loci have now been identified that can modulate sickle cell disease phenotype, from nucleotide motifs within the β-globin gene cluster, to genes located on different chromosomes. With recent success of the human genome project, it is anticipated that many more genetic modifiers of sickle cell disease will be discovered that can lead to the development of more effective therapeutic approaches. The multigenic origin of the variable phenotype in sickle cell disease will serve as a paradigm for the study of variation in phenotypes of all single gene disorders in man.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Tarsal coalition is a common abnormality of the hindfoot skeleton that only rarely leads to symptoms. These symptoms occur most commonly in adolescence but rarely can be found also in adults. Although most coalitions are congenital, as the consequence of autosomal dominant inheritance, coalitions also can be acquired by degenerative joint disease, inflammatory arthritis, infection, and clubfoot deformities. Fifty percent of all coalitions are bilateral. Talocalcaneal and calcaneonavicular coalitions are most commonly found, and patients frequently have more than one coalition in the same foot. Clinical symptoms of the tarsal coalition frequently follow a sequence of sprains or other minor injuries to the involved foot. This leads to a rigid, painful foot. The pain is worsened by continued activities. The frequently cited peroneal spastic flatfoot is an uncommon means of identifying a tarsal coalition. The diagnosis of the tarsal coalition is made on the oblique radiograph of the foot, which demonstrates the calcaneonavicular coalition. Computed tomography (CT) and magnetic resonance imaging scans show the presence and extent of other coalitions. Secondary signs for the presence of a coalition are talar beaking, anteater nose sign, and C sign. These secondary signs can be demonstrated best on a lateral view of the involved foot. Local anesthetic blocks under image intensifier or CT guidance can identify areas of joint degeneration, which are caused by the altered biomechanics of the foot. Initial treatment should consist of conservative therapy in the form of support or immobilization of the involved foot, change in the activities of the patient, and nonsteroidal anti-inflammatory medication. Surgical treatment in the form of a resection of the coalition should be reserved for those patients for whom conservative therapy has failed. Subtalar or triple arthrodesis should be reserved for those patients for whom all other therapy has failed.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Several medical complications can occur after scoliosis surgery in children and adolescents. They include the syndrome of inappropriate antidiuretic hormone; pancreatitis; cholelithiasis; superior mesenteric artery syndrome; ileus; pnemothorax; hemothorax; chylothorax; and fat embolism. This review focuses on the pathophysiology, diagnosis, and treatment of the various conditions that occur after correction of spinal deformity. Attention is given to recent literature specifically related to scoliosis surgery. Surgical complications like urinary tract infection, wound infection, and hardware failure will not be addressed.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Lower extremity bowing is a normal physiologic process that commonly occurs in walking children under the age of 2 years. After this age, any significant amount of residual bowing is abnormal and may be due to infections, traumatic physeal injuries, genetic predisposition, metabolic factors, or a combination of these. Of the pathologic conditions, infantile Blount’s disease is the most common and is predominantly found in obese children with an early onset of walking. Because of its frequency in occurrence and general tendency for spontaneous resolution, physiologic genu varum must be clearly distinguished from other pathologic processes that result in bowleggedness. Treatment of the latter cases may consist of early bracing or surgery.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

An orally administered antimicrobial regimen for the treatment of pharyngitis caused by group A β-hemolytic streptococci that could be given once daily and for less than 10 days would be convenient and might improve compliance, decrease cost, and result in fewer side effects compared with a regimen given multiple times daily for 10 days. Previous attempts to administer oral penicillin once daily or for less than 10 days were not successful. Several cephalosporins and azithromycin have been reported to be effective when administered once daily or for less than 10 days. However, large, comprehensive studies have not been performed. In addition, the spectra of these cephalosporins and azithromycin are much broader than that of penicllin, and, even when they are administered for short courses, they are more expensive. Therefore, these novel regimens cannot be endorsed and should not supplant penicillin as the agent of choice. In contrast, once-daily amoxicillin therapy appears to be effective, is inexpensive, and has a narrower spectrum of antimicrobial activity; if these findings are confirmed by additional investigations, it could become an alternative regimen for the treatment of pharyngitis caused by group A β-hemolytic streptococci.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Cat-scratch disease is an infection caused byBartonella henselae,a fastidious gram-negative bacillus acquired from exposure to an infected kitten or cat. The most common manifestation of human disease is lymphadenitis. Atypical forms of infection include Parinaud oculoglandular syndrome, stellate neuroretinitis, persistent fever without localizing signs, hepatosplenic infection, encephalopathy, osteomyelitis, and endocarditis. Immunocompromised individuals withB. hensalaeinfection may develop bacillary angiomatosis, bacillary peliosis, and relapsing bacteremia with fever syndrome. The bacillus is susceptible to several antibacterial agentsin vitro, including penicillins, cephalosporins, aminoglycosides, tetracyclines, macrolides, quinolones, trimethoprim and sulfamethoxazole, and rifampin. Greatest clinical efficacy has been observed following treatment with rifampin, ciprofloxacin, gentamicin, trimethoprim and sulfamethoxazole, clarithromycin, and azithromycin. In one placebo-controlled study, azithromycin therapy was associated with more rapid diminution in size of infected lymph nodes. The majority of cases of cat-scratch disease occurring in normal hosts do not require anti-infective therapy for resolution of infection.

ISSN:1040-8703    

出版商:OVID    

年代:2001

数据来源: OVID