Neonatal polycythemia-hyperviscosity syndrome
Introduction
Introduction to neonatal polycythemia - high viscosity syndrome Neonatal polycythemia-high viscosity syndrome is a common problem in the neonatal period. The exact etiology, pathophysiology, treatment and prognosis are still unclear. Neonatal polycythemia and high-viscosity syndrome are not synonymous. The name, often coexisting, is called neonatal polycythemia-high viscosity syndrome. As the blood viscosity increases, it affects the blood flow rate of various organs, resulting in hypoxia, acidosis and reduced nutrient supply. A series of symptoms. basic knowledge The proportion of illness: 0.001% - 0.003% Susceptible people: children Mode of infection: non-infectious Complications: pulmonary hypertension hypocalcemia hypoglycemia cerebral infarction cerebral hemorrhage neonatal necrotizing enterocolitis renal failure
Cause
Neonatal polycythemia - the cause of high viscosity syndrome
(1) Causes of the disease
The occurrence of this disease is related to some factors, should pay attention to the relevant medical history, the relevant factors are: 1 perinatal factors; 2 environmental factors; 3 post-natal umbilical cord ligation time, the cause of this disease can be divided into active and passive two categories.
Active type:
Placental insufficiency with intrauterine hypoxia can produce a large number of red blood cells, and reticulocytes and nucleated red blood cells also increase in the peripheral circulation, which may be due to the mediated effect of fetal erythropoietin, including small for gestational age Children, expired children, mothers have pre-eclampsia, severe heart disease, smoking and prenatal medication (such as propranolol), other causes of increased erythropoietin concentration or vitality can also occur, such as mothers with gestational diabetes, The child is Down syndrome, 13 or 18-trisomy syndrome, congenital thyrotoxicosis, congenital adrenal hyperplasia and Beckwith syndrome.
Passive type:
In the case of fetal red blood cell transfusion, the most common cause of normal term infants is delayed umbilical cord ligation. Some people have early and delayed ligation of the umbilical cord on the blood viscosity of other term neonates and other hemorheological parameters, and found early ligation. Umbilical cord (<10s), his hematocrit decreased from 0.48±0.04 at birth to 0.43±0.06 (24h after birth), no significant change in blood viscosity; and delayed ligation of umbilical cord (3min), hematocrit was born The time was 0.6±0.04, rose to 0.63±0.05 at 2h after birth, decreased to 0.59±0.05 at 24h, and the blood viscosity increased by 40% within 2h, but there was no significant change in the next 5 days. The passive type also included maternal-fetal transfusion. And the recipient of blood transfusion between twins.
(two) pathogenesis
The pathogenesis of this disease is multifactorial, can occur in prenatal, postpartum and postpartum, prenatal antenatal hypoxia can increase erythropoietin to lead to erythropoiesis; acute hypoxia and infant umbilical circulation intact, placental blood It can be moved to the fetus to increase its blood volume. In addition, as mentioned above, delayed ligation of the umbilical cord can also increase the blood volume of the newborn. This short-term increase in blood volume suddenly results in physiological compensation in the body, hematocrit. And the viscosity increases; the intravascular fluid exudates to the extravascular region and the blood is concentrated, and the flow rate of the liquid is inversely related to the viscosity. When the hematocrit and blood viscosity increase, the blood flow of all organs in the whole body decreases. The stroke volume decreased, and the right to left shunt at the level of the arterial catheter increased. When the hematocrit exceeded 0.7, the pulmonary vascular resistance gradually increased than the vascular resistance, and the cerebral vascular resistance also increased. Bada et al measured the brain with Doppler. The mean flow velocity (MFV) and the resistance index (PI) of the blood flow were observed to observe the cerebral hemodynamic changes of the syndrome. The results showed that there were symptoms. High-viscosity children had the highest PI, the lowest MFV, visible mucosa in the gastrointestinal tract, submucosal hemorrhage and necrosis, and a series of gastrointestinal symptoms including necrotic enterocolitis (NEC) within 24 hours after birth, combined with intrauterine In patients with growth retardation, the risk of NEC increases, and the amount of heart metastasis to the kidney is large. Therefore, the total renal blood flow in children with polycythemia is not significantly reduced, but the distribution of blood flow changes, leading to kidney. Changes in ball filtration rate and renal tubular reabsorption capacity, urine output, urinary sodium and urinary potassium excretion were significantly reduced, accompanied by an increase in blood urea nitrogen and creatinine, 1,25 dihydroxyvitamin D3 and 24,25 dihydroxyl Vitamin D3 was significantly decreased, presumably due to the reduced ability of the kidney to convert 25-hydroxyvitamin D3.
The rate of glucose disappearance increases in children with polycythemia. The occurrence of hypoglycemia may be caused by increased glucose uptake in the brain or a decrease in endogenous sugar production due to slow liver circulation. Hyperbilirubinemia is not only an increase in red blood cell destruction, but also due to Improper entry, decreased bowel movement caused by increased bilirubin intestinal-hepatic circulation. Other abnormalities in this disease include spiked red blood cells, red blood cell debris, increased nucleated red blood cells and thrombocytopenia in peripheral blood smears. Clinical manifestations of peripheral bruising and a patient's index finger gangrene.
Prevention
Neonatal polycythemia - prevention of high viscosity syndrome
Do a good job in pregnancy health care, prevent intrauterine hypoxia, prevent high-risk pregnancy, prevent maternal gestational diabetes, high blood pressure, pre-eclampsia, mother should not smoke during pregnancy, alcohol abuse, careful medication, improve delivery technology, prevent umbilical cord ligation delay.
Complication
Neonatal polycythemia - high viscosity syndrome complications Complications pulmonary hypertension hypocalcemia hypoglycemia cerebral infarction cerebral hemorrhage neonatal necrotizing enterocolitis renal failure
Some children can be complicated by heart, lung system symptoms, such as pulmonary hypertension, apnea, etc., complicated with hypocalcemia, hypoglycemia, cerebral infarction, cerebral hemorrhage, convulsions, spastic sputum, complicated with necrotizing enterocolitis, kidney Failure, heart failure, hyperbilirubinemia, acidosis, etc.
Symptom
Neonatal polycythemia - high viscosity syndrome symptoms common symptoms cyanosis abdominal distension heart failure antifeeding convulsion heart enlargement sleepiness microthrombus thrombocytopenic proteinuria
Because the disease involves various organs, the clinical manifestations have no characteristics, and most of the children have asymptomatic increases despite hematocrit.
1. Appearance: The appearance of the skin is normal. After the activity, the skin is red or blemish, showing more blood, and 35% of the children have hyperbilirubinemia.
2. Respiratory system: stagnant blood of the pulmonary circulation, causing gas exchange disorder, increased pulmonary circulation pressure, when the pulmonary circulation pressure is greater than the systemic circulation pressure, right-to-left shunt of the arterial catheter or the foramen ovale may occur, manifested as shortness of breath, cyanosis, and breathing. time out.
3. Circulatory system: due to insufficient coronary perfusion, decreased supply of oxygen and glucose, can cause myocardial damage, if there is an increase in blood volume and increased vascular resistance, resulting in increased heart rate, heart enlargement or even heart failure, microcirculatory system: blood viscous Increased microcirculation stasis, microthrombus formation and consumption of clotting factors and platelets, causing bleeding, larger thrombosis can cause thrombosis of the brain, coronary artery, lung, kidney, mesentery, omentum, extremities, etc. A series of corresponding symptoms.
4. Digestive system: can cause food, vomiting, bloating, gastrointestinal bleeding or necrotizing enterocolitis.
5. Nervous system: slowing of cerebral blood flow causes hypoxic-ischemic brain tissue, causing irritability, vomiting, apnea, low muscle tone, lethargy or even convulsions.
6. Urinary system: renal blood flow is reduced and oliguria, proteinuria, hematuria or even renal failure.
7. Blood system: hyperbilirubinemia, erythrocytosis, thrombocytopenia, etc. may occur.
8. Metabolism: due to slower blood flow, hypoglycemia and acidosis occur due to increased glucose consumption; hypoxia can damage hypocalcemia caused by parathyroid glands.
Examine
Neonatal polycythemia - high viscosity syndrome examination
After 12 hours of birth, venous hemoglobin (Hb) 220g / L, red blood cells (RBC) > 7.0 × 1012 / L, hematocrit (HCT) > 0.65 or 2 times peripheral blood capillary hematocrit (HCT) > 0.70 (centrifugation The speed should be 3500 rpm, and last for 30 minutes, which can avoid false positives. When the above three indicators are not completely consistent, the most important indicator is hematocrit (HCT), followed by hemoglobin (Hb), as long as hematocrit (HCT) is consistent with hemoglobin (Hb), which can be diagnosed. Only those with hemoglobin (Hb) should be reviewed within a short period of time.
Twin-child blood transfusion, the first delivery is mostly recipients, often this disease, and the fetal hemoglobin difference greater than 50g / L, can be diagnosed.
1. X-ray chest X-ray: You can understand the heart and lungs of the child, you can find an increase in the ratio of heart to chest, and changes in chest congestion.
2. Echocardiography: visible cardiac function decline.
3. Brain CT scan: see multifocal infarction, cerebral hemorrhage and water-borne brain abnormalities.
4. ECG examination: right atrial hypertrophy, ST segment changes and left ventricular hypertrophy.
Diagnosis
Diagnosis and differentiation of neonatal polycythemia-high viscosity syndrome
According to clinical characteristics and laboratory tests, more can be diagnosed.
Patients with clear central nervous system damage should be differentiated from intracerebral hemorrhagic disease; the same blood viscosity increases to microthrombus formation, consumption of clotting factors and platelets, and bleeding should be differentiated from hemorrhagic diseases; , necrotizing enterocolitis and other identification, the appearance of more blood quality and laboratory tests can help identify.
