Toxic dysentery in children
Introduction
Introduction to pediatric poisoning dysentery Poisoning dysentery (referred to as scorpion venom) is a serious type of bacterial dysentery, more common in children 2 to 7 years old. The onset is rapid, and the condition is extremely dangerous. If the patient is not treated in time, the child may soon have respiratory or (and) circulatory failure and die. basic knowledge The proportion of illness: 1.6% (the above is the probability of illness in infants and young children) Susceptible people: children Mode of infection: digestive tract spread Complications: disseminated intravascular coagulation renal failure hemolytic uremic syndrome
Cause
Pediatric poisoning type
(1) Causes of the disease
All types of dysentery bacilli can cause poisoning dysentery, no difference.
(two) pathogenesis
After the human body is infected with dysentery bacilli, a series of pathophysiological changes (called stress response or hypersensitivity reaction) occur under the action of bacteria and endotoxin. The general process is as follows: bacteria and its endotoxin inflammatory visceral autonomic nerve Pre-sympathetic parasympathetic nervous system excitatory sympathetic and parasympathetic acetylcholine and catecholamine secretion increased parasympathetic M receptor and sympathetic receptor excitation microvascular systolic disorder systemic acute microcirculation disorder, microcirculation refers to: microarterial Capillary network blood circulation between venules, the function of microcirculation is mainly to provide nutrients and oxygen to organs and tissues and take away metabolites. It is the material basis for the survival of organ tissue cells, and acute dysfunction occurs in microcirculation. , will lead to five stages of pathological changes in organ tissue cells:
Microcirculation ischemic period
In the early stage of the disease, the sympathetic nerve is stimulated. At this time, the secretion of catecholamines is increased, and the receptor is excited. The visceral arterioles, arterioles, anterior capillaries and muscular venules of the skin cause the peripheral vascular resistance to increase, and the microvascular volume is reduced. Tissue blood perfusion is reduced, causing brain tissue ischemia, hypoxia, clinical manifestations of gray, drowsiness, coma, convulsions.
2. Microcirculation and congestion
Ischemia and hypoxia stimulate the mast cells on the microvascular wall to release histamine. Histamine has the function of relaxing blood vessels, and at the same time, metabolic acidosis occurs in the ischemic phase. Acidosis also has the effect of relaxing blood vessels. These factors make the arterioles, the front capillaries. The anterior resistance vessels such as blood vessels are dilated, while the muscular venules are not sensitive to histamine and acidosis, and are still in a contracted state. The resistance is still high after the reduction of the pre-resistance, so that the microcirculation is more perfused and less, causing congestion in the microcirculation. Hypoxia, increased hydrostatic pressure in the capillary, increased permeability, oozing out of the intravascular fluid, forming edema of the brain tissue, clinical manifestations of increased intracranial pressure, increased coma, frequent seizures, cerebral edema and intracranial The pressure rises and oppresses the cranial nerve, and the cerebral palsy is induced to make the pupil side large and one side small. In severe cases, respiratory failure may occur and death may occur.
3. Shock period
Some children suffer from microcirculation disturbance of the visceral skin, a large amount of blood is deposited in the chest and abdomen, the blood volume is reduced, and the effective circulation is insufficient. In addition, the blood vessels of the skeletal muscle are mainly dominated by the M receptor and the 2 receptor. The receptor is stimulated to cause vascular expansion in the skeletal muscle, causing excessive blood perfusion of the skeletal muscle. This part of the blood accounts for about 1/3 of the cardiac output. Therefore, skeletal muscle congestion is also one of the important reasons for the reduction of effective circulation. The performance of cardiac output is reduced, blood pressure is reduced, the pulse is fine, the limbs are cold, the skin is faint, the hair can be cyanosis, the expression is indifferent, and severe cases can cause circulatory failure and death.
4. Diffuse intravascular coagulation (DIC)
After the microcirculatory disorder enters the blood stasis period, due to fluid extravasation in the capillaries, blood concentration, blood viscosity increases, acidic metabolites accumulate, platelet aggregation is destroyed, thromboplastin is released, severe lactate is inactivated by heparin, and vascular endothelium The cells are damaged, the collagen fibers are exposed, and the XII factor is activated. The above factors cause the blood to be hypercoagulable and contribute to DIC. At this time, extensive microthrombus obstructs the capillaries, further aggravating the microcirculatory disorder, and consuming a large amount of blood coagulation factors during coagulation. , thrombocytopenia, the body is resistant to DIC and secondary fibrinolysis, so the blood coagulation is reduced in the later stage, and the tendency to induce bleeding.
5. Organ failure period
Microcirculatory disorders are not resolved or continue to deteriorate. With the continued development of decompensation, cell metabolism and dysfunction become more and more serious, lactic acid accumulation in tissues, pH decreases, energy depletion, enzyme activity decreases, cell failure Lysosome rupture releases lysosomal enzymes, causing cell damage and necrosis. At this time, the pancreas releases myocardial inhibitory factor (MDF), which makes the heart function worse. Therefore, the microcirculatory disorder first causes the organ function to change, which in turn causes tissue. Cell necrosis occurs in organ failure, and poisoning dysentery is a systemic microcirculatory disorder, so severe cases can cause multiple organ failure in the body.
Poisonous dysentery is rapidly affected by systemic stress reaction. The gastrointestinal inflammatory lesions are mild and not serious. They are mainly found in the colon, followed by the small intestine and appendix. The intestinal mucosa is hyperemic and edematous. There are limitations in the lamina propria. Hemorrhagic foci, small blood vessels under the mucosa, blood stasis and edema, and some cases have obvious congestion and edema under the subserosal, ulcers are rare.
The pathological changes of internal organs in death cases are significant, and the damage of heart, brain and lung is serious. The cerebral edema is especially obvious, and the edema near the fourth ventricle of the brain stem is more obvious. This change may be caused by central respiratory failure and early death. The cause, in addition, brain cell degeneration can be seen, pulmonary congestion in the lungs, alveolar hemorrhage, alveolar and interstitial edema, coagulation or thrombosis in small blood vessels, these changes are particularly evident in pulmonary cases, myocardial changes have congestion, interstitial edema , cell degeneration, liver fatty degeneration, adrenal gland sometimes visible bleeding and cortical atrophy.
Prevention
Pediatric poisoning dysentery prevention
Prevention of dysentery should fully mobilize the masses, carry out extensive health education, and take comprehensive preventive measures: strengthen the health management of children, pay attention to personal hygiene, care for people and children to wash their hands with soap before and after meals; improve drinking water hygiene, prevent water sources Contaminated, do not drink raw water; strengthen the management of manure, the patient's feces should be soaked with 1% bleaching powder or poured with boiling water or sprinkled with quicklime before being poured into the sewer or septic tank. The diapers and underpants of the sick children should be cooked or used. Wash after soaking in boiling water; strengthen food hygiene, do not eat spoiled food, eat raw fruits to wash. Strengthen environmental sanitation, kill fly, kill cockroaches, and store food to prevent insect pollution. Early detection, early diagnosis, early treatment is the key to controlling the epidemic of dysentery. For atypical children, asymptomatic carriers (rare in childhood) and chronic dysentery are important sources of infection. , isolation, treatment, must pay attention to make acute dysentery into a chronic cause, such as rickets, malnutrition and other complications should be treated in a timely manner.
For the cooks of the collective children's institution, the nurses should regularly check the feces and, if necessary, do bacterial culture, and find that the carriers should be treated in time.
Complication
Pediatric poisoning dysentery complications Complications, disseminated intravascular coagulation, renal failure, hemolytic uremic syndrome
Severe cases often associated with DIC, renal failure, and occasionally combined with hemolytic uremic syndrome.
1. disseminated or diffuse intravascular coagulation (DIC)
It refers to the activation of coagulation factors and platelets by certain virulence factors, and a large amount of soluble procoagulant substances enter the blood, thereby causing a pathological process (or pathological syndrome) characterized by coagulopathy. A large number of microthrombus is formed in the microcirculation, and a large amount of blood coagulation factors and platelets are consumed, and the secondary fibrinolysis (fibrinolysis) process is strengthened, leading to clinical manifestations such as hemorrhage, shock, organ dysfunction, and anemia.
2. Renal failure symptoms
Proteinuria, azotemia, oliguria, polyuria, dehydration, hematuria, metabolic acidosis, hyperkalemia.
3. Heomlytic uremic syndrome (HUS)
It is a syndrome characterized by hemolytic anemia, thrombocytopenia and acute renal failure.
Symptom
Pediatric poisoning dysentery symptoms common symptoms irritability diarrhea hair sputum fiber exudate high fever lethargy sigh-like breathing limbs wet cold breathing difficulties light reflection slow
The incubation period is several hours to 1-2 days. The onset is urgent, rapid development, sudden high fever, body temperature of 39 ~ 40 ° C, or even higher, mental wilting, lethargy, repeated convulsions, coma, and even serious symptoms such as circulatory and respiratory failure. And gastrointestinal symptoms of diarrhea are often not obvious in the early stage, often need to be treated with 0.9% warm saline (200ml) enema to test the bottom of the stool, found that most white blood cells or see red blood cells can be diagnosed.
Due to the different degrees of microcirculatory disorders in various organs of the body, the following different types can be clinically displayed:
1. Brain type (brain microcirculatory disorder type)
Mainly caused by cerebral microcirculation disturbance, cerebral edema is obvious, mild expression of gray, dullness, lethargy, convulsions, cyanosis, rapid breathing, increased limb muscle strength, normal or slightly elevated blood pressure, severely showing the central Sexual respiratory failure: conscious coma, frequent or persistent convulsions, pale complexion, large pupil side, small side, slow or disappearing light reflection, uneven breathing, irregular rhythm or double inhalation, sigh-like breathing, The jaw is breathing, and then the number of breaths is gradually reduced to 12 times/min. This is a dangerous sign. If no special rescue is given, the child may suddenly stop breathing and die.
2. Shock type (skin visceral microcirculatory disorder type)
This type is mainly caused by visceral microcirculation disturbance in the skin. A large amount of blood stagnates in the periphery, and the effective circulation of blood is insufficient. The mild expression is clear, but there are irritability, wilting, pale, cold hands and feet, mild cyanosis, and skin. Hair flower, poor peripheral circulation, capillary refill time <2s, decreased urine output, increased pulse rate, small pulse pressure difference, slightly lower blood pressure; severe performance: blurred or coma, pale complexion, wet limbs, cyanosis, Skin spots on the extremities, peripheral circulation is worse, capillary refill time > 3s, pulse is weak or not touched, oliguria or no urine, blood pressure is significantly reduced or not detected.
3. Lung type (pulmonary microcirculatory disorder type)
Also known as respiratory distress syndrome, mainly due to pulmonary microcirculation disturbance, this type is rare, often developed on the basis of poisonous brain type or shock type, the condition is critically high and the mortality rate is mild, mild performance: irritability, dark complexion , rapid breathing, frequency > 35 times / min, progressive dyspnea, lung breath sounds reduced, X-ray visible lung reticular shadow, blood gas analysis, pH> 7.45, oxygen partial pressure <8.0kPa (60mmHg), carbon dioxide Pressure <4.67kPa (35mmHg); Severe performance: severe inspiratory dyspnea, large inhalation of the mouth (due to poor ventilation in the alveoli, severe hypoxia), progressively worsening of the cyanosis, lowering of the lungs, Tubular breathing sounds, sputum sounds, X-rays see large lung-like shadows in the lungs or extensive consolidation of the lungs, blood gas analysis pH <7.35, oxygen partial pressure <5.33 kPa (49 mmHg), carbon dioxide partial pressure >5.99 kPa (45 mmHg).
4. Mixed type
The above type 2 or type 3 existed at the same time or successively. At this time, due to severe microcirculation disturbance of the whole body, the blood flow perfusion of vital organs was sharply reduced, the tissue ischemia and hypoxia were serious, and even tissue necrosis occurred. Multiple organ failure occurs, and the mixed case fatality rate is very high.
Examine
Pediatric poisoning dysentery
Laboratory inspection
1. Peripheral blood: Most white blood cells and neutrophils are significantly increased.
2. Routine examination of feces: visual observation of mucus, mucus and blood, pus and blood, etc., microscopic examination of more white blood cells and red blood cells, and visible phagocytic cells.
3. Fecal bacterial culture: Take fecal pus or blood or mucus for immediate examination. Select appropriate medium and repeated cultures to increase the positive rate. Positive patients should be routinely identified and tested for drug susceptibility.
4. Rapid diagnosis method: rapid detection method such as fluorescent antibody staining, immunostaining method or slide solid phase antibody adsorption immunofluorescence technique can be used, which has the advantages of being fast, sensitive and simple, but its sensitivity and specificity still need further Improve, now PCR can be used for rapid diagnosis.
5. Determination of serum electrolyte and carbon dioxide binding: blood sodium, blood potassium, blood chlorine and carbon dioxide binding are mostly low.
6. Other examinations: including blood culture, DIC test, patients with drug abuse are easy to concurrently send DIC as needed.
Film degree exam
X-ray, chest electrocardiogram, brain CT examination can help to exclude other diseases, special inspection:
1. Observation of nailfold microcirculation: In the early stage of brain type, the number of moles of nail folds in the brain is reduced, and the shock type shows that the blood color becomes purple, and the blood flow is slow and uneven.
2. Fundus examination: visible small arteriospasm, severe retinal edema, increased intracranial pressure can be seen in optic disc edema.
3. Central venous pressure (CVP) measurement: normal value 0.59 ~ 1.18kPa (6 ~ 12cmH2O), CVP mainly reflects the dynamic relationship between blood flow and right ventricular bleeding function, can not express left heart function.
4. Other inspections: ECG, X-ray examination, etc. can be carried out as needed.
Diagnosis
Diagnosis and diagnosis of pediatric poisoning dysentery
diagnosis
1. Diagnosis of poisoning dysentery
Acute onset, rapid development, sudden high fever, stool (natural defecation or enema) examination found more white blood cells and red blood cells, one of the following conditions can be diagnosed as poisoning dysentery if it can rule out similar diseases.
(1) Symptoms of central nervous system poisoning: such as listlessness, lethargy, agitation, paralysis, convulsions, semi-coma or coma.
(2) Circulatory system symptoms: such as pale, cold limbs, weak pulse, small pulse pressure difference, blood pressure and so on.
(3) Respiratory symptoms: such as shallow breathing irregularities, sigh-like breathing, double inhalation, slow breathing, apnea, etc.
2. Diagnostic criteria for concurrent DIC
The diagnostic criteria for various types of pediatric septic shock symposiums in 1979 still have reference value, and the diagnostic criteria for DIC, laboratory tests: 3 of the following 5 abnormalities can be diagnosed.
(1) Progressive reduction of platelets: <80,000/mm3.
(2) Abnormal clotting time (test tube method): normal for 5 to 10 minutes, <3 min for hypercoagulable state and >12 min for hypocoagulable state.
(3) Abnormal red blood cell morphology: helmet-shaped, triangular, thorn-like or fragmented.
(4) Prolongation of prothrombin time: normal 12s, >15s when abnormal, or more than 3s longer than normal control.
(5) Fibrinogen reduction: <1.5 g/L or progressive decline.
In the above test items, if there are only 2 abnormalities, you need to add any of the following fibrinolytic indicators to diagnose:
1 Thrombin coagulation time, normal for 20s, abnormal > 25s or more than 3s longer than normal control.
The 23P test was positive.
3 euglobulin dissolution test time is shortened, <2h is positive.
4 whole blood clot lysis test, normal human whole blood coagulation, generally do not dissolve within 24h, DIC fibrinolysis can be dissolved within 0.5 ~ 2h.
Differential diagnosis
It should be identified with the following diseases:
Febrile seizure
The disease is more common in infants and young children. In the past, there was often a history of febrile seizures. The seizures occurred when the body temperature rose and did not recur. The color behind the convulsions was good, the mind was normal, and diseases causing high fever were often found.
2. Large leaf pneumonia
Both the disease and the poisonous phlegm are acute onset, and the total number of white blood cells and neutrophils in the peripheral blood rise, which may cause shock and cerebral edema in the early stage, but the X-ray examination may have large leaf or segmental inflammatory lesions in the lung.
3. Epidemic cerebrospinal meningitis
Both the cerebral palsy and the poisonous phlegm are acute and hot, and all have microcirculation disturbances caused by endotoxin, combined with convulsions, but the following characteristics are helpful to identify:
(1) The flow of the brain is mostly in the late winter and early spring, while the poisonous sputum is more common in the late summer and early autumn.
(2) More than 70% of patients with meningitis can see skin, mucosal bleeding spots and ecchymoses.
(3) The brain often has headaches, neck stiffness and other symptoms of central nervous system infection.
(4) You can ask about the history of meningococcal vaccination. If you have been vaccinated, you will rarely have a brain.
4. Epidemic encephalitis
Toadstools and JE are roughly the same due to the age of onset and the season of good development. The first symptoms are acute fever, accompanied by nervous system symptoms such as listlessness, lethargy, and convulsions.
(1) Different onset time: The onset time of the second disease is different. The poisonous phlegm is more convulsed on the day of onset, and the cerebral cerebral palsy occurs only after the third to fourth days of onset.
(2) signs of the nervous system: J brain has cervical rigidity, Kernig sign (+), Babinski sign (+) and other nervous system signs.
(3) Epidemic situation: There is a pandemic in the JE society.
(4) History of vaccination: Ask about the history of vaccination, such as vaccination, generally not JE.
(5) Cerebrospinal fluid examination: If there is doubt, it can be used for cerebrospinal fluid examination, JE protein and leukocytosis, sugar and chloride are normal, and poisonous cerebrospinal fluid is normal.
