EMC - Pédiatrie最新文献

Ascaris lumbricoides is a specific human parasitic disease. Ascariasis is the most frequent intestinal parasitic infestation. The geographical distribution is essentially in poor intertropicals countries where facilitating factors are climatic conditions and faecal peril. Hookworm live generally in jejunum. Morbidity and mortality are linked to intestinal obstruction or hepatobiliary and pancreatic ascariasis. Chronic infestation may be responsible to malnutrition in children when polyparasitism is frequent. Now medical treatment with benzimidazole antihelmintics is easy. Surgical treatment of complications is infrequently necessary. Struggle against poverty is principal factor influencing decreasing of ascariasis.

Once called “angiomas” or “vascular birthmarks”, lesions now called vascular anomalies were re-classified by the International Society for the Study of Vascular Anomalies (ISSVA) in two groups : vascular malformations and vascular tumours. This classification relies on the clinical, pathological, radiological and biological differences. Malformations are comprised of malformed, distorted, channels. They are slow-flow (capillary, venous or lymphatic) or fast-flow (with arteriovenous shunting). Complex combined forms exist, some being included in syndromes. Tumours grow by cellular hyperplasia, proliferation. The infantile haemangioma is the most common infantile benign tumour, while other vascular tumours recently individualised are far less frequent (i.e., congenital haemangiomas, tufted angioma, kaposiform haemangioendothelioma). Kasabach-Merritt phenomenon does not engraft on infantile haemangioma : it is a complication of either tufted angioma or kaposiform haemangioendothelioma.

Ante- and post-hypophysis are the two constituents of the hypophysis. The ante-hypophysis synthesizes and secretes mainly the growth hormone, thyrotropin, prolactin, adrenocorticotropic hormones and the gonadotrophins. The vasopressin and oxytocin hormones are secreted by the post-hypophysis. The hypophysis development and differentiation are controlled by a chain of different factors that involve numerous signalisation genes from adjacent structures, in addition to specific transcription factors, to date insufficiently known. The regulation and mode of action of the various hormones are now well identified. Activating and inhibiting hormones synthesized in the hypothalamus regulate the functioning of ante-hypophysis cells. They act through specific cellular receptors. In children, hypothalamus-hypophysis hypofunction is far more frequently observed than hyperfunction. Hypopituitarisms are serious diseases which, if untreated, may have irreversible consequences such as severe nanism in case of somatotropic insufficiency, mental retardation in case of thyrotropic insufficiency, lack of puberty development and sterility in case of gonadotropic insufficiency, and even death in case of corticotropic insufficiency. The diagnosis of hypophysis insufficiency is based on clinical data, and results of functional investigations, and brain magnetic resonance imaging. Treatments are substitutive, given for life, and concerned patients necessitate lifelong medical management. Hypophysis insufficiency may be either isolated or multiple, either acquired (mainly in relation with a tumoral or infiltrative process in the hypothalamus-hypophysis area), or congenital. Various types of human congenital insufficiency (isolated or combined) due to a genetic cause have been described these last years. However, the molecular mechanisms that produce the major part of genetic hypopituitarisms remain to be elucidated.

Urolithiasis is not uncommon in children and must be looked for with ultrasonography in any case of pyuria, hematuria or abdominal pain. By means of precise analysis of stone composition or, failing stone, of urines, an etiology can be found in approximately 80 % of child lithiases. In younger children, the two main causes are infection due to urease-producing bacteria, associated or not with urinary tract malformations, and metabolic disorders induced by prematurity and treatment of its complications (furosemide, steroids). In older children, metabolic disorders, particularly those due to inherited diseases, account for the majority of stones : hypercalciurias, secondary, iatrogenic or idiopathic, hyperoxalurias, primary (inherited), secondary, or “mild idiopathic”, cystinuria, hyperuricosurias, inherited or secondary, and other purine excretion disorders. Prevention of stone recurrence, essential in case of underlying metabolic disorder, always requires an abundant water intake (1.5-2 l/m²/day) associated with specific treatment of the causal disease if possible. If a surgical treatment is necessary, extra corporeal shock-wave lithotripsy is the first option like in adults.

The respiratory syncytial virus (RSV) causes 50% to 90% of all bronchiolitis cases in infants. The occurrence and severity of bronchiolitis are dependent on patient-related factors (preterm birth, comorbidities, individual susceptibility), virus-related factors (RSV A), and environmental factors (pollution, environmental tobacco smoke, and others). Mortality rates in infants with bronchiolitis range from 0.005% to 0.2% according to patient-related factors. The pathophysiology of RSV bronchiolitis is unknown but clearly involves direct effects of the virus on the airway epithelium, airway immaturity, and recently identified effects of the inflammatory response. Immunopathologic mechanisms (e.g., IgE antibodies and CD4⁺ Th2 cells) play a role in some infants or in severe forms. Complete immunity to the virus is never achieved, and repeat infections are common in the young and the elderly, in whom the RSV causes about 5% of all lower respiratory tract infections. VPI3 infections usually cause bronchiolitis, whereas VPI1 and VPI2 infections manifest chiefly as laryngotracheitis. Little is known about the clinical expression of VPI4 infection. Bronchiolitis due to hMPV is indistinguishable from RSV bronchiolitis.

Respiratory syncytial virus (RSV), parainfluenza virus (PIV), and human metapneumovirus (hMPV) are members of the Paramyxoviridae family. These pleomorphic viruses have an RNA containing about ten genes and a lipid envelope covered with glycoprotein projections that bind the virus particle to the cell membrane then ensure penetration of the virus within the cell. Although these viruses induce neutralising antibodies that play a major role in combating the infection, the virus-infected cells are eliminated by the cell-mediated immune response. RSV infections occur regularly each year as winter outbreaks that peak in December or January. The incidence of RSV-related bronchiolitis has increased significantly over the last 10 years. VPI3 is endemic and causes infections from September through March, whereas VPI1 and VPI2 are less common and manifest mainly as small irregular outbreaks, often in the autumn. Finally, hMPV is responsible for outbreaks that coincide with RSV outbreaks but are far more limited.

The diagnosis of infection due to the respiratory syncytial virus (RSV) and parainfluenza virus (PIV) rests chiefly on detection of the virus or its antigens in a nasal specimen. The diagnostic yield depends on the number of respiratory cells collected in the specimen. RSV infection can be diagnosed rapidly using immunofluorescent assays and immunoenzymetric assays. Immunofluorescent assays are more difficult technically than immunoenzymetric assays but provide an assessment of the quality of the specimen. Virus isolation in cell cultures and detection of the viral RNA by reverse transcriptase-polymerase chain reaction techniques are possible for both the RSV and the PIV; however, these sophisticated, time-consuming, and costly tests now have a limited role as diagnostic tools.

Heart disease in children is usually a chronic and severe condition that intrudes into all the phases of development and therefore governs the patient’s life. The physical health problems are compounded by the secondary development of psychological and social difficulties. The ability to lead as normal a life as possible determines quality of life, eventual self-sufficiency, and therefore the chances for a completely successful treatment. The paediatrician and family physician should have a global approach to the problems met by the child and family, who often need help in overcoming the obstacles met in their daily lives. Relationships within the family, school, professional training, sporting activities, potential effects on usual childhood diseases, and nutritional consequences regularly require the physician’s attention, to the same extent as the treatment and follow-up of the heart disease itself.

Except during neonatal period, acute renal failure (ARF) is less frequent in children than in adults. The two leading causes in paediatric population are hemolytic-uremic syndromes observed in infants and in young children less than 3 years and ARF related to renal hypoperfusion that occurred in all ages. In new-borns, ARF is mainly related to perinatal asphyxia. Hyperkalaemia and fluid overload are life-threatening complications, which have to be promptly prevented by treatment. Technical advances in renal replacement therapies (peritoneal dialysis [PD], hemodialysis [HD] and continuous hemofiltration [CHF]) permit to provide stable control of fluid and metabolic status with sufficient caloric intake even in hemodynamically unstable patients and in tiny infants. PD remains the favoured method of dialysis in infants and young children even if CHF takes a growing place, particularly in treatment of multiple organ failure. Nowadays, mortality observed in ARF is mainly associated with extra-renal pathologies and is higher in neonatal period and in critically ill children. Risk of irreversible renal lesions with chronic renal failure is variable depending of aetiology and duration of IRA.