Gastroenterology PDF

**[Gastroenterology]** [Features of gastrointestinal disorders in children] - Acute abdominal pain requires detailed evaluation to identify surgical, gastrointestinal and extra- gastrointestinal causes. - Vomiting and diarrhoea are common and usually transient; serious causes are unco...

**[Gastroenterology]** [Features of gastrointestinal disorders in children] - Acute abdominal pain requires detailed evaluation to identify surgical, gastrointestinal and extra- gastrointestinal causes. - Vomiting and diarrhoea are common and usually transient; serious causes are uncommon but important to identify. - Worldwide, gastroenteritis is one of the most common causes of death in children under 5 years of age. - The number of children and adolescents developing inflammatory bowel disease is increasing, but in contrast to adults, bowel cancer is extremely rare. - Constipation is common and often requires long-term treatment. **[Acute abdominal pain]** - The differential diagnosis of acute abdominal pain in children is extremely wide, including both surgical causes and medical conditions, not only of the gastrointestinal tract but also external to it - Of the surgical causes, appendicitis is by far the most common. In children it is essential not to delay the diagnosis and treatment of acute appendicitis, as pro- gression to perforation can be rapid. It is easy to be little the clinical signs of abdominal tenderness in young children. However, in nearly half of the children admitted to hospital with acute abdominal pain, the pain resolves undiagnosed. - It is noteworthy that: 1. Lower lobe pneumonia may cause pain referred to the abdomen. 2. Primary peritonitis is seen in patients with ascites from nephrotic syndrome or liver disease. 3. Diabetic ketoacidosis may cause severe abdominal pain. 4. Urinary tract infection, including acute pyelonephritis, is a relatively uncommon cause of acute abdominal pain, but must not be missed. A urine sample should be tested, in order to identify not only diabetes mellitus but also conditions affecting the urinary tract. 5. Pancreatitis may present with acute abdominal pain and serum amylase should be checked. 6. The testes in boys, hernial orifices and hip joints must always be checked. 7. Consider gynaecological problems in older females, and if testing for pregnancy is required A urine sample should be tested to identify not only diabetes mellitus but also conditions affecting the urinary tract **[1-Acute appendicitis]** - Acute appendicitis is the most common cause of abdomi- nal pain in childhood requiring surgical intervention - Although it may occur at any age, it is very uncom- mon in children under 3 years of age. The clinical features of acute uncomplicated appendicitis are: 1. anorexia 2. vomiting 3. abdominal pain, initially central and colicky (appendicular midgut colic), but then localizing to the right iliac fossa (from localized peritoneal inflammation) 1. fever 2. abdominal pain aggravated by movement, e.g. on walking, coughing, jumping, bumps on the road during a car journey 3. persistent tenderness with guarding in the right iliac fossa [(McBurney's point);] however, with a **retrocaecal appendix**, localized guarding may be absent, and in a **pelvic appendix** there may be few abdominal signs. preschool children: - It is uncommon but potentially serious. - The diagnosis is more difficult, particularly early in the disease. - Perforation may be rapid, as the omentum is less well developed and fails to surround the appendix, and - the signs are easy to underestimate at this age. - Appendicitis is a progressive condition and so repeated observation and clinical review every few hours are key to making the correct diagnosis,. No laboratory investigation or imaging is consistently helpful in making the diagnosis. - A raised neutrophil count is not always present on a full blood count. - Although ultrasound is no substitute for regular clinical review, it may support the clinical diagnosis (**thickened, non-compressible appen- dix with increased blood flow**), and demonstrate associ- ated complications such as an **abscess**, **perforation** or **an appendix mass**, and may exclude other pathology causing the symptoms. - Appendicectomy is straightforward in uncomplicated appendicitis. - Complicated appendicitis includes the presence of an [appendix mass, an abscess, or perforation]. If there is generalized guarding consistent with perforation, fluid resuscitation and intravenous antibiotics are given prior to laparotomy. - If there is a palpable mass in the right iliac fossa and there are no signs of generalized peritonitis, it may be reasonable to elect for conservative management with intra- venous antibiotics, with appendicectomy being performed after several weeks. If symptoms progress, laparotomy is indicated **[2-Non-specific acute abdominal pain and mesenteric adenitis]** - Non-specific acute abdominal pain is abdominal pain which resolves in 24--48 hours. - The pain is less severe than in appendicitis, and tenderness in the right iliac fossa is variable. It often accompanies an upper respiratory tract infection with cervical lymphadenopathy. - In some of these children, the abdominal signs do not resolve and laparoscopy and an appendicectomy is performed. - Mesenteric adenitis is often diagnosed in those children in whom large mesenteric nodes are observed and whose appendix is normal, but there are doubts whether this condition truly exists as a diagnostic entity. - Constipation is a common cause of non-specific abdominal pain, which may have an acute onset and be severe and accompanied by vomiting in extreme cases. #### [3=Intussusception] - It most commonly involves ileum passing into the caecum through the ileocaecal valve (**Intussusception is the most common cause of intestinal obstruction in infants after the neonatal period**. - Although it may occur at any age, the peak age of presentation is 3 months to 2 years of age. - The most serious complication is **stretching** and **constriction** of the mesentery resulting **in venous obstruc- tion**, causing engorgement and bleeding from the bowel mucosa, fluid loss, and subsequently **bowel perforation, peritonitis** and **gut necrosis.** - immediate fluid resuscitation and urgent reduction of the intussusception are essential to avoid complications. 1. Paroxysmal, severe colicky pain with pallor -- during episodes of pain, the child becomes pale, especially around the mouth, and draws up the legs. There is recovery between the painful episodes but subsequently the child may become increasingly lethargic. 2. May refuse feeds, may vomit, which may become bile-stained depending on the site of the intussusception. 3. A sausage-shaped mass -- is often palpable in the abdomen 4. Passage of a characteristic **redcurrant jelly stoo**l comprising blood-stained mucus -- this is a characteristic sign but tends to occur **later** in the illness and may be first seen after a rectal examination. 5. Abdominal distension and shock - Usually, no underlying intestinal cause for the intussus- ception is found, although there is some evidence that viral infection leading to enlargement of Peyer's patches may form the lead point of the intussusception. - An iden- tifiable lead point such as a Meckel diverticulum or polyp is more likely to be present in children over 2 years of age. Intravenous fluid resuscitation is likely to be required immediately, as there is often pooling of fluid in the gut, which may lead to hypovolemic shock - An X-ray of the abdomen may show distended small bowel and absence of gas in the distal colon or rectum. Sometimes the outline of the intussusception itself can be visualized. Abdominal ultrasound is helpful both to confirm the diagnosis (the so-called target/dough- nut sign, [Fig. 14.3c](#_bookmark210)) and to check response to treat- ment. Unless there are signs of peritonitis, reduction of the intussusception by rectal air insufflation is usually attempted by a radiologist. This procedure should only be carried out once the child has been resuscitated and is under the supervision of a paediatric surgeon in case the procedure is unsuccessful or bowel perfora- tion occurs. - The success rate of this procedure is about 75%. The remaining 25% require operative reduction ([Fig. 14.3d](#_bookmark211)). Recurrence of the intussusception occurs in less than 5% but is more frequent after hydrostatic reduction. -  **[4-Meckel diverticulum]** Around 2% of individuals have an ileal remnant of the vitello-intestinal duct, a Meckel diverticulum, which con- tains ectopic gastric mucosa or pancreatic tissue. - Most are asymptomatic but they may present with severe rectal bleeding, which is classically neither bright red nor true melaena. - There is usually an acute reduction in haemoglo- bin. Other forms of presentation include intussusception, volvulus (twisting of the bowel), or diverticulitis, when inflammation of the diverticulum mimics appendicitis. - A technetium scan will demonstrate increased uptake by ectopic gastric mucosa in 70% of cases ([Fig. 14.4](#_bookmark212)). A negative technetium scan does not exclude the possibility and a laparoscopic examination can be used to make the diagnosis. **Treatment is by surgical resection** #### [5-Malrotation and volvulus] Malrotation is a congenital abnormality of the midgut, in which the small intestine most commonly lies predominantly on the right-hand side of the abdomen, with the caecum in the right upper quadrant. - This results from a failure of the intestine to 'rotate' into the correct position during fetal life and secure or 'fix' the mesentery in the correct position. The reason for this developmental failure is unknown. - Fibrous bands called 'Ladd bands' tether the caecum to the right upper quadrant and these cause intestinal obstruction by compressing the duodenum (Fig. 14.5a,b).  - The poorly-tethered gut is able to swing and twist more readily, resulting in volvulus. There are two presentations: 1. obstruction 2. obstruction with a compromised blood supply. 3. Obstruction with bilious vomiting is the usual presenta- tion in the first few days of life but can be seen at a later age. - Any child with dark green vomiting needs an urgent upper gastrointestinal contrast study to assess intestinal rotation, unless signs of vascular compromise are present, when an urgent laparotomy is needed. - This is a **surgical emergency** as, when a volvulus occurs, the superior mesenteric arterial blood supply to the small intestine and proximal large intestine is compromised, and unless it is corrected it will lead to infarction of these areas - At operation, the volvulus is untwisted, the duodenum mobilized, and the bowel placed in the non-rotated posi- tion with the duodenojejunal flexure on the right and the caecum and appendix on the left. The malrotation is not 'corrected', but the mesentery broadened. The appen- dix is generally removed to avoid diagnostic confusion should the child subsequently have symptoms suggestive of appendicitis - **[Recurrent abdominal pain]** - Recurrent abdominal pain is a common childhood problem. - It is often defined as episodes of abdominal pain at least 4 times per month sufficient to interrupt normal activities and lasts for at least 2 months. - It occurs in about 10% of school-age children. The pain is charac- teristically periumbilical and the children are otherwise entirely well. - An organic cause needs to be identified but is present in less than 10% of cases ([Fig. 14.6](#_bookmark214)). This requires a full history and thorough examination. Particular attention needs to be paid to identify functional constipation, which is common and may cause abdominal pain, and coeliac disease, and inflammatory bowel disease. - The perineum should be inspected for anal fissures and other perianal disease and child maltreatment needs to be considered. The child\'s growth should be checked. The aim is to avoid subjecting the child to unnecessary investigations. - 'Red flag' features to help identify organic causes are listed in [Box 14.1](#_bookmark215). Investigations are guided by clinical features but baseline screening tests to be considered are listed in [Box 14.2](#_bookmark216)**.** - irritable bowel syndrome (most common) - abdominal migraine - functional dyspepsia - functional abdominal pain (not otherwise specified, i.e. do not meet above classification). #### [Irritable bowel syndrome (IBS)] - defecation - alteration in stool frequency - change in appearance of stool (diarrhea or constipation). - Children with functional constipation also often report pain and distinguishing it from IBS can be problematic. - If the abdominal pain resolves with constipation treat- ment, the child has functional constipation. If pain does not resolve after treatment, the child is likely to have IBS with constipation. [Pathogenesis] - IBS is now considered a disorder of visceral hypersensitiv- ity and neurological hypervigilance in combination with psychosocial stressors (see [Fig. 14.7](#_bookmark217)). - Patients are par- ticularly sensitive to low- or high-pressure stimuli in the bowel, as shown by children with IBS reporting discomfort at lower rectal distention pressure than controls. - These changes appear to be secondary to insults of the gut-- brain--microbiota axis and neuro-immune interactions in the gut, which alter the perception of pain. - These insults may vary widely -- 1. genetic (e.g. family history of irritable bowel syndrome), 2. early life events (e.g. bowel surgery), 3. environmental (e.g. cow's milk protein allergy, post enteri- tis) 4. gastrointestinal (e.g. infections, antibiotics) 5. psychosocial triggers (e.g. stress, anxiety, maltreatment). In some children, a vicious cycle of anxiety with escalating pain leading to family distress may develop, accompanied by demands for increasingly invasive investigations #### Abdominal migraine In abdominal migraine there are paroxysms of [intense], [acute] [periumbilical], [midline or diffuse abdominal pain, lasting at least an hour], [interfering with normal activities]. Additional symptoms may be 1. 2. 3. 4. 5. 6. - - #### [Functional dyspepsia] - The pain is not relieved by defecation but may be induced or relieved by eating. - There is some evidence for delayed gastric emptying as a result of gastric dysmotility. There is no evidence in children that *Helicobacter pylori* gastritis causes dyspeptic symptoms in the absence of duodenal ulcer. - Duodenal ulcers are uncommon in children but should be considered in those with epigastric pain, - particularly if it wakes them at night, if the pain radiates through to the back, or when there is a history of peptic ulceration in a first-degree relative. These can be caused by *H. pylori* infection. - **Initial diagnosis of *H. pylori* infection is generally made with gastric biopsy on endoscopy**. - Non- invasive tests such as ^13^C breath test, which detects urease produced by the organism following the administration of ^13^C-labelled urea by mouth, or stool antigen tests for *H. pylori* are used to confirm successful eradication of - *H. pylori* infection. In children, non-invasive tests are not recommended for initial diagnosis and treatment. - Children in whom peptic ulceration is suspected or diagnosed on endoscopy should be treated with proton- pump inhibitors, e.g. omeprazole, and eradication therapy with antibiotics should be given ***[Vomiting]*** *Posseting and regurgitation are terms used to describe the non-forceful return of milk, but differ in degree. **Posseting** describes the small amounts of milk that often accompany the return of swallowed air (wind), whereas **regurgitation** describes larger, more frequent losses. Posseting occurs in nearly all babies from time to time.* - - *When assessing the clinical features of vomiting:* 1. *Figures of speech such as 'bringing everything up' need to be picked apart: mild viral vomiting may result in a temporary inability to tolerate solids, but sips of liquids are 'kept down* 2. *The word 'bile' may be used by parents or older children to mean 'clear acidic stomach contents'**. The presence of green bile in vomit is an emergency,** as it suggests that the bowel is obstructed and the flow of bile is reversed.* 3. *In intestinal obstruction, **the more proximal the obstruction, the more prominent the vomiting and the sooner it becomes bile-staine**d, unless the obstruction is proximal to the ampulla of Vater.* 1. *Small quantity of blood in vomit may be swallowed blood, from a cracked nipple in a breastfed baby or nose bleeds in older children. **True haematemesis is a 'red flag'** clinical feature.* 2. *Abdominal distension in intestinal obstruction becomes increasingly pronounced the more distal the obstruction* 3. *When accompanying bouts of coughing it needs to be distinguished from spontaneous, unprovoked, vomiting.* 4. *The child who is systemically unwell needs to be identified, as it may be a feature of systemic infection, which may be outside the gastrointestinal tract, especially urinary tract and central nervous system, and other serious illness* [**Box 14.3** 'Red flag' clinical features in the vomiting child] - - - - - - While common in the first year of life, nearly all sympto- matic reflux resolves spontaneously by 12 months of age. This is probably due to a combination of maturation of the lower oesophageal sphincter, an upright posture and more solids in the diet. - Whilst gastro-oesophageal reflux is usually a benign, self-limited condition, if complications are present (Box 14.4), it is called gastro-oesophageal reflux disease. This is more common in: 1. children with cerebral palsy or other neurodevelopmental disorders 2. preterm infants 3. following surgery for oesophageal atresia or diaphragmatic hernia 4. obesity 5. hiatus hernia - Gastro-oesophageal reflux is usually diagnosed clinically and no investigations are required. - However, they may be indi- cated if the history is atypical, complications are present, or there is failure to respond to treatment (see [Case history 14.1](#_bookmark221)). 1. [24-hour oesophageal pH monitoring] to quantify the degree of acid reflux, with a pH probe passed through the nose into the lower oesophagus 2. [wireless pH monitoring], when the probe is placed in the distal oesophagus endoscopically and pH is monitored remotely, which is particularly helpful in children with neurodevelopmental or behavioural problems 3. [24-hour impedance monitoring], with a probe in the lower oesophagus, is available in some centres. 4. [endoscopy] including oesophageal biopsies to identify oesophagitis and exclude other causes of vomiting. - A contrast study of the upper gastrointestinal tract is not recommended to diagnose or assess the severity of gastro-oesophageal reflux disease in infants, children and young people. ##### **[Management]** - A 1--2-week trial of alginate therapy, which forms a protec- tive gel above stomach contents, may be considered, if these other methods are ineffective. - Gastro-oesophageal reflux disease is managed with stomach acid suppression with either hydrogen receptor antagonists or proton-pump inhibitors **(e.g. omeprazole).** - - non-bilious vomiting, which increases in frequency and forcefulness over time, ultimately becoming - feeds normally after vomiting until dehydration leads to loss of interest in feeding - weight loss if presentation is delayed. - Gastric peristalsis may be seen as a wave moving from left to right across the abdomen ([Fig. 14.10a](#_bookmark223)). -  Classically, pyloric stenosis has been confirmed by per- forming a test feed, where the baby is given a milk feed which initially calms the hungry infant, and allows for examination. - The diagnosis is made if the pyloric mass, which feels like an **olive, is palpable in the right upper quadrant** ([Fig. 14.10b](#_bookmark223)). As the stomach is usually overdistended with air, - This has been replaced by ultrasound, which has become the standard diagnostic procedure by visualizing the hypertrophied pylorus ([Fig. 14.10c](#_bookmark223)). - the **definitive treatment is surgical (pyloro- myotomy),** - this performed safely after acid-base electrolyte imbalances have been corrected, which may take more than 24 hours of intravenous fluid rehydration. ([Fig. 14.10d](#_bookmark223)) **[GASTROENTRITIS]** #### #### [Lactose intolerance] - Lactose intolerance is a form of malabsorption, - where lactase enzyme is not expressed on the microvilli of the intestine. Lactose is not broken down into glucose and galactose, - this results in recurrent bloating, abdominal pain and foul-smelling 'yeasty' stool whenever dairy prod- ucts are consumed. Some experience nausea and vomiting. - Lactose intolerance is often secondary to viral gastroen eteritis - it resolves after several months of dairy-free exclusion diet, during which lactase starts to be expressed again - In rare cases, lactose intolerance can be congenital, in which case it is caused by a genetic inability to produce lactase. - Lactase supplements are available, but they are easily denatured by stomach acid, so are not always effective. - This condition, previously known as toddler diarrhoea, - It is the most common cause of persistent loose stools in preschool children. - Characteristically, the stools are of varying consistency, sometimes well formed, sometimes explosive and loose. The presence of undigested veg- etables in the stools is common. - Affected children are well and thriving. In a proportion of children the diar- rhoea may result from undiagnosed coeliac disease or excessive ingestion of fruit juice, especially apple juice. - Occasionally the cause is temporary cow's milk allergy following gastroenteritis, when a trial of a cow's milk protein free diet may be helpful. - Once possible underly- ing causes have been excluded, in the majority of cases the loose stools probably result from dysmotility of the gut (a form of irritable bowel syndrome) and fast-transit diarrhoea; it almost always improves with age