septic shock in children
Introduction
Introduction to pediatric septic shock Septic shock is very common in the clinic. It is caused by pathogenic microorganisms such as bacteria, viruses, fungi, rickettsia, and acute circulatory dysfunction caused by harmful products, resulting in shock caused by insufficient blood perfusion. Also known as septic shock, septic shock, is the body's immune response to the pathogen (immunoinflammatoryresponse) out of control, causing circulatory (macrocirculation) and microcirculation (microcirculation) dysfunction, and ultimately lead to cell metabolism and organ dysfunction circulatory failure syndrome In recent years, with the deep understanding of the two basic pathological processes of infection and shock, the microscopic and macroscopic understanding, the pathogenesis, localization and clinical diagnosis and treatment principles of septic shock are undergoing profound changes. basic knowledge Sickness ratio: 0.0001% Susceptible people: children Mode of infection: non-infectious Complications: renal failure
Cause
Pediatric septic shock etiology
Bacterial infection (45%):
Infectious shock is more common in clinical bacterial infection: (1) Gram-negative bacilli: The most common cause is Gram-negative bacilli, such as Escherichia coli, Shigella, Meningococcus, and Klebsiella pneumoniae. Pseudomonas aeruginosa, Proteus, etc., account for about 50% of the cause. (2) Gram-positive bacteria: Staphylococcus aureus, pneumococci, streptococci, etc. are common in Gram-positive bacteria. (3) Conditional pathogens: In recent years, some conditional pathogens such as Klebsiella, Salmonella, Proteus and some anaerobic bacteria have an increasing trend of septic shock.
Disease factors (25%):
In pediatric diseases, fulminant meningitis, poisonous bacillary dysentery, sepsis, severe pneumonia, acute necrotizing enterocolitis, epidemic hemorrhagic fever, etc. are often prone to shock. Primary leukemia, malignant lymphoma, cirrhosis and other severely ill children, children treated with hormones or immunosuppressants, cytotoxic drugs, and children undergoing catheterization or various diagnostic punctures in intensive care units are easy. Infections occur, and infections are more common with drug-resistant conditions, and shocks are also prone to occur. Therefore, septic shock is also common in hospital-infected patients.
Pathogenesis
1. New concept or opinion
The new concepts or perspectives on infection and shock are mainly:
(1) Uncontrolled inflammatory immune response: It is the initial mechanism of septic shock. When systemic or local infection occurs, pathogens stimulate the body cells (mainly vascular endothelial cells, neutrophils and mononuclear macrophages) to produce various pro-inflammatory And anti-inflammatory mediators, due to the pro-inflammatory/anti-inflammatory balance disorder, systemic inflammatory response syndrome (SIRS) or compensated anti-inflammatory response syndrome (CARS), which is The mechanism of septic shock, microcirculatory disorders and neuro-endocrine, humoral factor disorders may be the result of these molecular biological changes, they are the pathophysiological mechanisms of shock at different levels of the whole, and affect each other to form a vicious circle.
(2) SIRS caused by various pathogens such as bacteria, viruses, fungi, etc.: all called sepsis (note: different from the concept of "sepsis" in which bacteria grow and reproduce in circulating blood), from sepsis, septic shock Multiple organ dysfunction syndrome (MODS) is a continuous process of development and development. Infectious shock is a stage of MODS. It usually occurs before MODS, but it can also be secondary to MODS or It happens repeatedly in the process.
(3) septic shock: it is one of the most common pathological processes leading to death from severe and chronic diseases. There are often two or more mechanisms of shock, such as hypovolemic shock, blood flow, shock, and heart. Sexual shock and multiple organ dysfunction are impaired. On the other hand, the advanced stages of non-infectious shock, the refractory shock stage, have the same pathogenesis as septic shock.
2. Pathogenesis
(1) Neuro-endocrine and humoral factor mechanisms: Scholars have found that in addition to microcirculatory disorders, hemodynamic disorders and organ dysfunction in septic shock are also associated with neuromodulation and humoral factor regulation disorders. Related to the rapid response of the neuroendocrine system at the time of infection, the sympathetic-adrenal system and the renin-angiotensin-aldosterone system are excited, the secretion of stress hormones such as catecholamines, adrenocortical hormones is increased, and various active humoral factors have been found in recent years. Normally, these factors have extremely low concentrations in circulating blood, which are significantly increased in shock, and can be increased by 10 times or even thousands of times. They are composed of organ parenchymal cells (such as neuronal cells, cardiomyocytes), vascular endothelial cells and immune cells. Produced in the form of neuro-endocrine or autologous (parallel) secretions involved in the following pathogenesis of shock:
1 vasomotor dysfunction.
2 endothelial cell inflammatory response, increased vascular permeability.
3 myocardial inhibition.
4 coagulation fibrinolysis regulation disorder.
(2) Molecular biology research: Molecular biology studies of "immune inflammatory response" and "gene expression abnormality" shock found that the first change in septic shock is the regulation of cytokines and inflammatory mediators under pathogen stimulation. Cellular energy metabolism disorders, many animal experiments have shown that this molecular level disorder is the root of the shock microcirculation and humoral factor disorder mechanism, cell hypoxia further leads to intracellular information transmission disorders (such as nuclear transcription factor NF-B and heat The activation of the shock protein HSP-70) and the severe disorder of the gene's orderly regulation mechanism make the body's expression of inflammatory, immunoregulatory proteins, enzymes or cytokine synthesis genes (transcription and replication abnormalities), at this time shock is seen In order to obtain sexual genetic diseases, the regulation of gene levels may be the basis of irreversible shock.
Clinically different stages of shock can be characterized by hemodynamic abnormalities, cellular energy metabolism disorders or multiple organ failure, respectively, as a result of the combined effects of the above three different mechanisms.
Prevention
Pediatric septic shock prevention
We will do a good job in prevention and health care for children of all ages, promote breastfeeding, prevent vaccination, strengthen children's physique, rectify the environment, air pollution, public health, and disease prevention. To maintain the function of important organs, septic shock is caused by the interaction of the body fluid system and inflammatory cells under the action of microorganisms and their toxins, resulting in damage to vital organs such as brain, heart and kidney. Observe whether the circulation around the child is improved, whether the urine volume is increased, and the changes of the original underlying diseases should be closely observed.
Complication
Pediatric septic shock complications Complications, renal failure
Severe cases often occur multi-system, multiple organ failure, children with lung, brain, heart, kidney, liver, gastrointestinal and coagulation and other functional failures more common.
Symptom
Symptoms of pediatric septic shock Common symptoms oliguria, anuria, limbs, cold, low blood pressure, pale heart, low blunt, respiratory alkalosis, blood pressure, circulatory failure, shortness of breath, shortness of breath
1. pale or lip, finger toe bun, purple skin.
2. The hands and feet are cold, and the capillary refilling time is prolonged.
3. The pulse speed is fine, the blood pressure drops, and even the measurement is not possible, and the pulse compression is small.
4. Reduced urine output.
5. Ambiguous, indifferent expression.
6. Anal temperature difference > 6 °C.
Examine
Pediatric septic shock examination
In the case of shock, you can choose central venous pressure, pulmonary wedge pressure, cardiac output, blood gas analysis, blood lactate determination, urine output and other monitoring items to guide clinical treatment, children with infection symptoms are not obvious, should be blood, Urine routine and blood, secretion culture, direct smear and other tests to confirm the infection.
Blood test
Infected patients with white blood cell count and neutrophils significantly increased, can be found that platelets decreased significantly, prolonged clotting time and so on.
2. Urine check
Reduced urine output, proteinuria and so on.
3. Blood test
Blood gas analysis has hypoxemia, PaO2<60mmHg or PaO2/FiO2<300, hyperlactosis, prolonged prothrombin time, abnormal liver function, elevated transaminase, decreased albumin, increased bilirubin, and elevated blood sugar. Creatinine>176.8mol/L, increased urea nitrogen, increased blood potassium and so on.
4. Pathogen inspection
Blood, secretion culture, direct smear and other tests to confirm the infection, and now there are specific antigen methods for determining the cell wall of pathogenic bacteria such as latex agglutination test, enzyme-linked immunosorbent assay, etc., which can clear pathogens in a short time. Endotoxin testing is helpful in diagnosing Gram-negative bacterial infections, and conditions can be performed.
5. You can choose central venous pressure, cardiac output and other tests, according to clinical needs to choose X-ray chest X-ray, B-ultrasound, ECG, brain CT and other examinations.
Diagnosis
Diagnosis and diagnosis of pediatric septic shock
diagnosis
1. Have a primary infectious disease.
2. The complexion is pale, the tip and mucous membrane are bun, the skin pattern changes, and the hair is cold.
3. Pulse speed, capillaries refill time 2 seconds.
4. Reduced urine output, mild shock 5 to 10 ml per hour for infants, 10 to 20 ml for children, less than 5 ml per hour for severe shock, and less than 10 ml for children.
5. Blood pressure drops to the limit, pulse pressure <4Kpa (30mmHg), early mild shock blood pressure can be normal.
6. Apathy, confusion, and rapid breathing.
Differential diagnosis
1. Should pay attention to the identification of shock or shock status
(1) Unrecognized shock state exists: mistakenly believe that blood pressure drop is shock, even in the presence of cold hair in the limbs, prolonged skin capillary refilling time and low perfusion of organs, it is still generally attributed to "some original Onset + heart failure, "primary disease + brain edema", if the condition continues to progress, sudden heart rate slowdown or disorder, it may be diagnosed as "heartbeat respiratory arrest", "after cardiopulmonary resuscitation", blood pressure drop rescue invalid death , "breathing, circulatory failure" is the cause of death.
(2) Misunderstanding of the clinical situation of shock: convulsions caused by neurological central lesions with acute mental and transient blood pressure changes, such as toxic dysentery cerebral edema type, small infants with late vitamin K deficiency intracranial hemorrhage, leukemia with intracranial hemorrhage or Toxic encephalopathy, vagal syncope, autonomic dysfunction, etc., but it must be pointed out that the above conditions can occur in various types of shock when the condition is severe or the blood pressure is continuously reduced.
2. Identification with other types of shock
This is a clinical problem that has been divided in recent years. Although shock taxonomy is constantly evolving, there is no universally accepted and clearly feasible shock classification system. The complexity of shock etiology and clinical manifestation determines the diversity of its classification and Cross-overlapping, clinical interventions, especially the development of critical care medicine, have made the traditional shock classification unsuitable for clinical applications. Here, only the common clinical conditions of pediatrics are described:
(1) Non-infectious shock:
1 cardiogenic shock: severe acute heart failure, arrhythmia, congenital heart disease, congenital heart disease, poisoning, chemotherapy drugs, fulminant myocarditis.
2 hypovolemic shock: enteritis with severe dehydration, hemorrhagic shock (digestive tract, intracranial or surgical site, etc.), large area burn exudation, small infants with high fever accompanied by vomiting and diarrhea, nephrotic syndrome excessive fluid restriction diuretic, etc., can cause Hypovolemic shock.
3 obstructive shock: a variety of intracardiac or extracardiac obstruction, such as pericardial tamponade, valvular stenosis or obstruction, severe pulmonary embolism.
4 blood flow distribution shock: such as anaphylactic shock, neurogenic shock.
5 mixed shock: such as heat stroke, pancreatitis, some poisoning, adrenal crisis and so on.
The above-mentioned types of shock can cause systemic infection through the translocation of intestinal bacterial toxins, and develop into septic shock, causing cell tissue oxygenation metabolic disorders and organ dysfunction, and should be vigilant in clinical practice.
(2) Septic shock in different periods: The mechanism of shock in different periods of septic shock may be different. Septic shock may have multiple pathogenesis at the same time or alternately, and the frequency or speed of change is more than previous knowledge. There are a variety of mixed mechanisms for the occurrence of shock under certain incentives. It is necessary to combine the primary disease and organ function status, combined with the onset of the disease, and carefully analyze the treatment response to find out the main contradiction.
