Page 8 of 73 NORMAL PHYSIOLOGICAL PROCESSES
Process of maturing of the alimentary system is reflected in nature of its functioning during various age periods. Such functional shifts should not be confused to manifestations of morbid conditions. MAIN SYMPTOMS OF DISEASES OF THE DIGESTIVE TRACT
Mechanisms of a proglatyvaniye of food are well developed and coordinate already by the time of the birth. The baby first experiences difficulties when swallowing dense food as language pushes out it, but does not advance towards a throat, but the correct skill is soon developed. Rather short bridle does not influence a food proglatyvaniye. At suction the baby swallows a lot of air. Therefore it is reasonable to stimulate at it an eructation during meal; otherwise stomach stretching will prevent air absorption of food. Flavoring feelings form by the end of the first month of life, and the child begins to prefer sweet and salty. The first milk teeth are cut through in 6 — 10-month age (section 12.3).
Vomiting by gastric contents, observable is very frequent at children of the first year of life, happens until they do not begin to carry out the most part of day in vertical position. This not absolutely studied phenomenon can accompany each feeding; over time vomiting, as a rule, stops.
Frequency of meals and appetite of the child during various age periods seem strange to those who got used to eat food 3 times a day. Parents are terrified often by ability of the starting walking child to absorb very large number of food after within several days he refused usual food. It, however, absolutely normal phenomenon. Appetite varies in huge limits. During the periods of rapid growth (chest and teenage age) appetite is huge while in intermediate years some children at first sight almost eat nothing though they normally grow and gain body weight.
The quantity, color and consistence a calla considerably vary both at the same child, and at children of one age irrespective of food and environmental conditions. First-born the kcal (meconium) represents dark, viscous, sticky weight. When feeding begins milk, instead of meconium the kcal, and then, in 4 — 5 days is allocated olive-brown curdled, it gains yellowish-brown color. Defecation frequency at absolutely healthy babies fluctuates from 1 to 7 times a day. Color the calla has no special value; the exception makes blood impurity. At some children issued by kcal appears only in 2 — 3-year age. At the children nursed irregular defecations by a yellow stake of a soft consistence usually are observed. Later, when the vegetable food is entered into a diet, in Calais it is possible to see covers of grains of corn and peas.
The condition of abdominal organs of the healthy child sometimes causes unreasonable concern. In the first 3 — 4 years of life the muscles of a front abdominal wall are quite weak, abdominal organs are rather big and the lordosis of a lower part of a backbone is considerably expressed. Therefore small children stomach evaginated and soft. At children 2 years are not more senior the soft liver edge is palpated 2 cm below than the right costal arch. The spleen usually is not palpated, but at acute infectious diseases it is possible to probe its soft lower pole.
Loss of blood through a digestive tract — always the symptom of pathology, but also the swallowed blood can be taken for a symptom of intestinal bleeding easily. Blood of mother can get into a digestive tract of the child at the time of delivery or when feeding by a breast if the bleeding point is near a nipple. Children can swallow own blood at bleeding from a nose or a nasopharynx.
Jaundice is noted approximately at 20% of all children who were born in time; the probability of jaundice is directly proportional to prematurity degree. At most of newborns not the disease, but inability of a liver to process a large amount of decomposition products of hemoglobin into the first weeks of life is the reason of jaundice.
It is very important to establish a pathogeny of the main symptoms of diseases of digestive organs at children because the reasons of many of them are unknown, and specific effective methods of treatment are not developed. The mechanisms which are the cornerstone of the leading clinical displays of diseases of digestive organs are briefly given below.
Swallowing disturbance. Considerably pathological changes in some sites of an upper part of a digestive tract can break swallowing.
Passing dysphagy. Disturbance of receipt of food in upper part of a gullet indicates pathology in a mouth or a throat. Movement of food from a mouth in a gullet is carried out as a result of consecutive neuromuscular acts. At suction of a lip form a dense ring around a nipple; language departs back. The epiglottis closes an entrance to respiratory tracts, the soft palate rises and closes a nasopharynx. The Perstneglotochny part of the lower constrictor of a throat relaxes, and the food comes to a throat. A similar series of coordinate movements is necessary for a proglatyvaniye of dense food; the movements of jaws are important. The saliva which is actively emitted waiting for food and at the act of swallowing moistens a food lump. Even at the expressed anomalies of development of a mouth, teeth and sialadens the act of swallowing at the hungry child passes quite well.
At children disturbances of the muscular device participating in the act of swallowing (frustration of an innervation, force and coordination of reductions) often are the cornerstone of a passing dysphagy. In such cases of change of the neuromuscular device of a mouth and throat usually are part of more generalized pathology. Sometimes swallowing is temporarily broken because of severe pains in an oral cavity (for example, at acute viral stomatitis or an injury). Decrease in passability of the nasal courses seriously breaks suction process.
Dysphagy, vomiting. The movements of a gullet — self-regulating process in which important role is played by zones of a high pressure (sphincters) in the upper and lower ends of a gullet. The child is born with well developed swallowing mechanism. Primary peristaltic wave arises when swallowing and extends down a gullet. The secondary wave clearing a gullet of the food remains is stimulated with its stretching. Vomiting can arise under the influence of the reasons connected with a gullet (full or partial obstruction) or other factors when, for example, the prelum of a trachea conducts to cough or a stridor).
Primary disturbances of motive function of a gullet causing frustration of a vermicular movement and a dysphagy occur at children seldom.
The lower esophageal sphincter interferes with throwing of gastric contents in a gullet (section 12.20). If pressure of this sphincter is reduced, then contents of a stomach move retrogradno, causing nutritive loss and eventually insufficiency of food. It is necessary to tell, however, that the least patients have no accurate communication between function of a sphincter and weight of a gastroesophagal reflux. In many cases hernia of an esophageal opening of a diaphragm is not the important reason of a gastroesophagal reflux.
Long impact of a gastric juice on a mucous membrane of the lower part of a gullet can become the reason of an esophagitis or a chronic loss of blood. At gullet dyskinesia, especially at dysfunction of an upper sphincter of a gullet, aspiration of a gastric juice is possible.
Anorexia. The centers of hunger and saturation are in a hypothalamus. There is a set of ways on which at diseases of digestive organs to these centers the pathological impulses causing loss of appetite go. A special role is played by the afferent ways connecting a digestive tract to a hypothalamus. For example, the center of saturation is stimulated with stretching of a stomach or upper part of a small bowel; the signal is transmitted on touch fibers which especially there is a lot of in this department of a digestive tract. From intestines chemoceptors information on existence in digestion of nutrients also comes to the center of appetite. To a hypothalamus from the highest centers there are signals caused by pains or emotional reactions which arise at intestinal diseases. The centers of hunger and saturation are affected by also circulating factors (for example, hormones and glucose) which maintenance, in turn, depends on a condition of intestines.
Vomiting. The mechanism of vomiting consists in sharp relaxation of a diaphragm and simultaneous sharp reduction of muscles of an abdominal wall. At the same time gastric contents with a force are thrown out a gullet. Vomiting arises at irritation of the emetic center in a brain. In this center, apparently, there are chemoceptors which react to the substances circulating in blood. Therefore vomiting can arise almost at any disease and especially at damage of a brain.
Impassability of a digestive tract at the level of the gatekeeper or behind it probably owing to afferent stimulation of the emetic center can become the reason of vomiting. If the lower part of a duodenum is impassable, then in emetic masses there is a bile impurity. Not only the obstruction, but also defeat of proximal departments of a large intestine, pancreas, liver, bilious channels can be the cause of vomiting. Besides, heavy pernicious vomiting is observed at the wet brain caused by metabolic disturbances (for example, owing to hepatocellular insufficiency at Ray's syndrome).
In rare instances rough vomiting itself can cause the injury of a mucous membrane of cardial part of a stomach which is followed by bleeding (Mallori's syndrome — Weiss).
Diarrhea. Diarrhea is defined as excessive loss of liquid and electrolytes with a stake. Water passively passes through covers of an intestinal wall. This process depends on active and passive transport of the substances dissolved in water, in particular sodium, chlorides and glucose. Disturbance of transmembrane transport of such substances is the cornerstone of all forms of diarrhea. In the majority of clinical situations the major factor defining diarrhea is defeat of an epithelium; the hyperkinesia of intestines plays less highest role in this process, and is known of value of blood supply or a lymph drainage very little. Almost all water, except for small residual amount, is soaked up in a small bowel therefore severe diarrhea arises at defeat of this body. At damage of a large intestine diarrhea is not so expressed, liquid the kcal alternates with issued.
At intestines diseases disturbance of transmembrane transport is caused by injury of a mucous membrane or development of stimulators of secretory function of intestines which get to an epithelium from blood or a gleam of a gut. Injury of a mucous membrane leads not only to reduction of the soaking-up surface, but also to the expressed disturbance of functions of the remained cells. For example, at rotavirusny enteritis glucose transport is broken, activity of disaccharidases and Na+-K+-of ATP-ase is reduced and, therefore, Na transport regulated by glucose + through an epithelium of a small bowel is broken.
The metabolites of bacteria strengthening secretion do not change the area of a vsasyvatelny surface and structure of an epithelium of intestines. Such most powerful irritant as the choleragen produced in a gut cavity by a cholera vibrio communicates a brush border of an intestinal epithelium and, influencing a pas activity of adenylatecyclase, stimulates accumulation of tsAMF in epithelium cells. The most severe watery diarrhea at which a large amount of chlorides cosecretes results, sodium chloride absorption is broken, but remain unlike a situation at viral enteritis the sodium absorption controlled by glucose and Ma's activity + - To +-ATF-azy. Other stimulators of intestinal secretion (circulating in blood hormones, gastrin, vasoactive intestinal peptide) promote accumulation in tsGMF epithelium cells that also causes diarrhea. Some fatty acids and salts of bile acids excite secretory function of a large intestine, however the mechanism of this phenomenon is unknown. Vozmoyasho, that the diarrhea arising after a resection of distal part of an ileal gut and also against a steatorrhea, is caused by this phenomenon.
Lock. Rare by dry kcal it is observed at disturbance of filling or that is more often, rectum emptyings. Disturbance of filling of a rectum is connected with weakness of a vermicular movement, for example at a hypothyroidism and reception of opiates, and also with the obstructive phenomena (anomalies of development, an illness of Girshprunga). The contents delay in intestines leads to excessive dryness of fecal masses and, therefore, to reduction of their volume; for this reason the reflexes implementing the act of defecation do not "work". Rectum emptying — the reflex act which is excited by pressure receptors which are in its muscles. Therefore, damage of these muscles, afferent and efferent fibers of sacral department of a spinal cord, muscles of a front abdominal wall and a pelvic bottom, and takya "e the pathology of a proctal sphincter interfering its relaxation can be the cause of a lock.
It should be noted that the lock tends to self-maintenance irrespective of the reason which caused it. Firm large fecal accumulations complicate defecation and cause pains therefore the child detains bowel emptying that aggravates a lock; thus the vicious circle is created. Rastyayazheniye of a direct and large intestine reduces efficiency of a vermicular movement, weakens sensitivity of receptors of a rectum. In certain cases liquid contents of proximal departments of a gut can flow round dense fecal masses and involuntarily be allocated outside. Such state — enkoprez — often mistakenly take for diarrhea. The lock has no systemic adverse effect on an organism, though he, and alarm of surrounding persons can affect the emotional sphere of the child. At a long persistent lock there is a danger of spillage of developments of stagnation in an urinary system.
Abdominal pains. Reactions to pains in an abdominal cavity are very individual, but anyway the doctor has to regard an abdominal pain as reality. Though it is often difficult to define an actual reason of pain, clinical inspection usually allows to establish the nature and localization of defeat. The painful impulses arising in abdominal organs are transferred on nerve fibrils of two types. On fibers of type A painful impulses from skin and muscles, and on fibers of type C — from internals, a peritoneum and muscles are transferred. The impulses which are transferred on fibers of type A cause feeling of the acute and accurately localized pain, and on fibers of type C — uncertain dull ache. The afferent neurons transferring painful impulses from abdominal organs are in gangliya of back roots of a spinal cord, and some axons cross the average line and go back to a cerebellum, a mesencephalon and a thalamus. Perception of pain happens in a postcentral crinkle of a cerebral cortex which receives impulses from both half of a body.
Pain arising in abdominal organs is felt as a pas the level of that segment from which the struck body is innervated. The painful impulses proceeding from a liver, a pancreas, a biliary path, a stomach and upper part of intestines are perceived as pain in epigastriums. The distal part of a small bowel, a caecum with a worm-shaped shoot, all proximal half of a large intestine give pains in paraumbilical area. At defeat of distal department of a large intestine, uric ways and bodies of a small pelvis of pain are felt in suprapubic area. If pain irradiates in the zone having the general with it an innervation, remote from the struck body, then it testifies to high intensity of the pathological center. The parietal peritoneum is innervated by S-fibers which correspond to the Th6 — Li segments; parietal pains are more limited and intensive in comparison with visceral.
In a digestive tract the main factor provoking pain is stretching and a prelum of body. Inflammatory process, apparently, reduces a threshold of a sensation of pain, however origins of painful impulses at an inflammation are not absolutely clear. At ischemia pain is caused probably by release of fabric metabolites in the field of nerve terminations. It is obvious that perception of painful signals depends both from cerebral, and on peripheral factors. The perception of pain in many respects is defined by a psychological state of the patient.
Gastrointestinal bleeding. Bleeding can arise in any site of a digestive tract, but most often its source is localized in the lower piece of a gullet, in a stomach, a duodenum and a large intestine. Usually as the reason of bleeding serves the deep ulceration of a mucous membrane eroding intraorganic vessels. In addition, it is necessary to call anomalies of development of vessels and supertension in system of a portal vein. Defects of coagulant system are the rare reasons (an exception hemorrhagic syndromes at newborns make). If bleeding arose in a gullet, a stomach or a duodenum, it can be shown by a hematemesis. Under the influence of gastric or intestinal juice blood darkens, gaining color of a coffee thick. Therefore, than proksimalny and massivny bleeding, that a high probability of the fact that blood will be red. Not changed blood in Calais indicates loss it in distal part of intestines or on massive bleeding above the bauginiyevy gate. Slight or moderate bleedings from a small bowel can be shown by a black chair of a tar-like consistence (melena). Such chair is constantly observed at massive bleedings from a duodenum or a stomach.
Even considerable gastrointestinal bleeding can proceed asymptomatically. At the child zhelezodefitsitpy anemia whereas the research a calla on the occult blood conducted from time to time yields a negative take develops. Bleeding seldom causes any subjective feelings in a digestive tract, however acute gastric or duodenal bleeding can be followed by nausea or vomiting. Against the broken function of a liver absorption of a large amount of decomposition products of blood can cause a hepatic coma in the patient.
Increase in a stomach or abdominal organs. Increase in a stomach can be a consequence of decrease in a tone of a front abdominal wall, and also accumulation in an abdominal cavity of liquid, gas or dense masses. At accumulation of liquid in an abdominal cavity (ascites) the stomach stretches sideways and forward. Usually astsitny liquid represents transudate with low protein content; it is formed as a result of decrease in colloid osmotic pressure of plasma at a hypoalbuminemia or owing to portal hypertensia, and also at a combination of both factors. At portal hypertensia liquid, apparently, filters from absorbent vessels on a surface of a liver and from capillaries of a visceral peritoneum; ascites usually arises only after decrease in level of a seralbumin. For the unknown reason accumulation of astsitny liquid is followed by sharp decrease in excretion of sodium with urine, and the sodium arriving with food gets directly to a peritoneal cavity owing to what the amount of liquid increases in it even more. Astsitny liquid can be also exudate, for example at inflammatory processes or new growths.
At inspection of the patient with ascites it is possible to observe how the percussion fluctuations caused in one part of a stomach extend to another. Therefore, this sign, along with the shift of a zone of percussion dullness, can be used for diagnosis of ascites. At accumulation of liquid in a gastric cavity or intestines these phenomena are not observed.
If the digestive tract is stretched by the liquid which accumulated in it, it is necessary to suspect impassability or disturbance of balance between processes of absorption and secretion. Often same factors promote accumulation of gases. In such cases at inspection of the patient it is possible to hear the characteristic gurgling sounds in a stomach. Gases get into a digestive tract, as a rule, owing to an aerophagia at meal. A small amount of gases is produced by endogenous microflora, but at absorption disturbance when contents of a small bowel get into a large intestine, the amount of gases can sharply increase. Presence of gas at a peritoneal cavity what the percussion tympanic sound over a liver testifies to, always speaks about accident in an abdominal cavity, namely about perforation.
Its diffusion increase or emergence in it discrete educations can cause damage to any abdominal organ. Such educations are localized in a cavity of body, in its wall or in a mesentery. It is necessary to carry "fecal stones" to intracavitary educations — the mobile dense fecal masses which are palpated at the children suffering from locks. In walls of a stomach and intestines there can be cysts, other anomalies of a structure and inflammatory infiltrates; fortunately, tumors occur at children extremely seldom. Many diseases are followed by diffusion increase in a liver. Local increase in a liver can be an island of normal regeneration at the patient with cirrhosis, but in each case it is necessary to exclude inflammatory or neoplastic process.
Jaundice. Yellow coloring of fabrics is caused by a dipirrolovy pigment, bilirubin which is formed at hemoglobin disintegration. Therefore the states connected with the strengthened destruction gem conduct to excessive products of bilirubin. If the number of the last does not correspond to ability of hepatocytes to remove bilirubin, then the content of untied bilirubin increases in serum and fabrics. Bilirubin of plasma is taken a hepatocyte where contacts specific ligands and conjugated with glucuronic acid, forming bilirubin diglucuronide. If mechanisms of linkng with ligands and conjugation are broken, then in serum and fabrics untied bilirubin collects. Such bilirubin is insoluble in water and in serum is in a type of a complex with albumine owing to what it is not filtered in glomerula and does not paint urine. In physiological conditions excretion of rather soluble connected bilirubin in water in bilious tubules comes from hepatocytes quickly; it gives to bile yellow green coloring. From a gall bladder bile comes to intestines where under the influence of the bacteria living in distal part of an ileal gut and in a large intestine, bilirubin dekonjyugirutsya. Urobilinigen is also produced in distal part of an ileal gut; in the same place it reabsorbirutsya, and then is excreted with bile and urine. Disturbances of excretion of bilirubin can arise both owing to damage of hepatocytes, and at obstruction inside - or extrahepatic bilious ways. Clinical manifestations of defects of excretion the calla and disappearance of urobilinigen from urine include increase of level of the conjugated bilirubin in serum and fabrics, emergence of this soluble pigment in urine, and, depending on obstruction degree, decolorization.