Intussusception is the most suggested case here based on the child’s symptoms. The urgent course of treatment is to bring the child to a paediatric surgical unit. If air reduction attempts fail, surgery will have to be done. Risk factors for intussusception include viral infection and intestinal lymphadenopathy.

Haemolytic Uremic Syndrome affects children and is characterised by abdominal pain, a purpuric rash over the body, generalized pallor, haematuria and bloody diarrhoea. There is always a history of preceding diarrhoea caused usually by E.coli and it affects the renal system causing haematuria and deranged renal function tests.

The most common cause for acute bloody diarrhoea in a 10-year-old child is Campylobacter.Note:Campylobacter is the most common bacterial cause of gastroenteritis in the UK. It typically presents with bloody diarrhoea, fever, abdominal pain and vomiting. The primary source of Campylobacter is uncooked poultry. Treatment is generally supportive unless the child is immunosuppressed or the symptoms are persistent.Other options:- E. coli 0157:H7: It causes acute haemorrhagic diarrhoea, usually afebrile. It can lead to haemolytic uremic syndrome (haemolytic anaemia, acute renal failure and thrombocytopenia), which is the commonest cause of acute renal failure in children.- Rotavirus: It rarely causes bloody diarrhoea.- Salmonella and Yersinia: While they can cause bloody diarrhoea, they are much less common compared to Campylobacter.

Based on the given scenario, the most probable diagnosis for this patient is acquired immune deficiency syndrome (AIDS) caused by human immunodeficiency virus (HIV). Thus, the most appropriate investigation to confirm the underlying pathology in this patient would be viral serology. Rationale:The presence of oesophageal candidiasis is highly suggestive of severe immunosuppression. The causes of immunosuppression can be chemotherapy, with haematological malignancy, HIV or inhaled steroids. In patients with HIV, oesophageal candidiasis is part of the spectrum of AIDS-defining illnesses and usually occurs when the CD4 count is < 200 cells/microL. Other AIDS-defining illnesses include PCP pneumonia and CMV infections.Oesophageal Candidiasis:It is characterised by white spots in the oropharynx with extension into the oesophagus. It seldom occurs without an associated underlying risk factor like broad-spectrum antibiotic usage, immunosuppression and immunological disorders.Patients may present with oropharyngeal symptoms, odynophagia and dysphagia.Treatment is directed both at the underlying cause (which should be investigated for) and with oral antifungal agents.

Biliary atresia is a rare condition that usually becomes symptomatic 2 to 8 weeks after birth. It can be congenital or acquired. Typical symptoms include jaundice, weight loss, dark urine and pale stools.

European guidelines suggest that triple therapy for 1 week is acceptable and sufficient for H. pylori eradication. Although triple therapy for 2 weeks might have higher therapeutic rates, it also carries a higher risk of side effects. Triple therapy includes amoxicillin and clarithromycin and a proton-pump inhibitor, usually omeprazole.

The patient has bloody diarrhoea that sounds like a food poisoning in the clinical scenario. Campylobacter is the most common cause of this in the United Kingdom. This is then followed by Salmonella and Shigella. The symptoms are usually self limiting. This is more likely to be bacterial from the food than a viral gastroenteritis.

In pyloric stenosis a new-born baby presents with a history of vomiting, constipation and deranged electrolytes. Excessive vomiting leads to hypokalaemia. Difficulty in food passing from the stomach to the small intestine causes constipation. Hypokalaemia also causes constipation. None of the other disorders mentioned present with the hypokalaemia, vomiting and constipation triad in a new-born.

Based on the presentation, the patient is probably a case of Crohn’s disease. The first-line treatment of Crohn’s disease is exclusive enteral nutrition.Exclusive enteral nutrition (EEN)This involves drinking a protein-based formula exclusively for 6–8 weeks. It has been shown to have superior mucosal healing when compared with steroids. Furthermore, it is nutritionally advantageous when compared to steroids and does not have the side-effect profile of steroids.Other options:- Intravenous steroids: This is the first-line treatment for ulcerative colitis (UC) or Crohn’s disease if there is rectal disease (which is not the case here). Side-effects include adrenal suppression, behavioural effects, osteopenia and changes in adipose tissue distribution.- Oral steroids: This can be used if EEN is not possible. However, the side-effect profile is less favourable and is not as effective concerning mucosal healing.- Parental nutrition and surgery: They may be occasionally required in severe cases that have failed first-line therapy.

The most probable diagnosis in this patient is lead poisoning.Lead poisoning: While it is not common, it can be potentially fatal. One of the key presenting features here is pica, the ingestion of non-nutritive substances such as soil, soap, paper or wood. Pica can also be observed in children in iron-deficiency anaemia, developmental delay and pregnancy. However, in a child who is exposed to lead in their environment (e.g. from lead paint or pipes), lead poisoning is most likely. It is commonly associated with iron deficiency which in turn increases the lead absorption. Treatment is either with oral D-penicillamine or intravenous sodium calcium edetate.

Unconjugated bilirubin is conjugated to glucuronic acid in the hepatocyte. Conjugated bilirubin passes into the enterohepatic circulation and the bilirubin which evades this system is metabolised by bacteria, primarily in the large intestine, to urobilinogen, then stercobilinogen and eventually oxidised to stercobilin. Stercobilin gives faeces its brown colour.

Breast milk jaundice is associated with breast-feeding. It typically occurs one week after birth and can sometimes last up to 12 weeks, but it rarely causes complications in healthy, breast-fed infants. The exact cause of breast milk jaundice isn’t known. However, it may be linked to a substance in the breast milk that prevents certain proteins in the infant’s liver from breaking down bilirubin. The condition may also run in families. Breast milk jaundice is rare, affecting less than 3 percent of infants. When it does occur, it usually doesn’t cause any problems and eventually goes away on its own. It is safe to continue breast-feeding.

Pyloric stenosis affects infants, typically in the second to fourth weeks of life and is caused most commonly by hypertrophy and thickening of the pylorus. It usually presents with projectile vomiting and failure to thrive. The infant usually has a normal appetite. Features include: ‘projectile’ vomiting, typically 30 minutes after a feed, constipation and dehydration may also be present and a palpable mass may be present in the upper abdomen.

Coeliac disease is associated with the following conditions:- Dermatitis herpetiformis- Autoimmune disorders (e.g. thyroid disease, pernicious anaemia, diabetes)- IgA deficiency- Small-bowel malignancy, particularly lymphoma, if the gluten-free diet is not followed.Serology testing: The IgA tissue transglutaminase antibody is the most sensitive and specific, compared with the anti-endomysial antibody. However, false negatives will occur in children who are IgA-deficient, and IgA levels should be taken at the same time. Other options:Distal obstruction syndrome, meconium ileus, pancreatitis and rectal prolapse are all gastrointestinal manifestations of cystic fibrosis.

Bulimia nervosa is an eating disorder that involves frequent episodes of binge eating followed by inappropriate purging behaviour. The underlying reason for this behaviour is distorted self-image. Bulimia leads to several medical issues, including various laboratory derangements. Among these deranged laboratory parameters are the hormone cholecystokinin, which is found to be decreased in women having bulimia. It is hypothesized that the bingeing episodes observed in patients with bulimia are due to lower levels of CCK since normal levels of CCK are involved in maintaining satiety and controlling the urge to binge eat.

From the midgut derives most of the small intestine as well as some parts of the large intestine, including the appendix. The appendix is at the base of caecum, up to 10cm long and mainly comprised of lymphoid tissue (Hence mesenteric adenitis may mimic appendicitis).

CUTANEOUS DISORDERS OR DERMATOSIS ASSOCIATED WITH IBD- Psoriasis- Secondary amyloidosis- Vitiligo- Acquired epidermolysis bullosaIn some cases, non-granulomatous skin disorders occur as a reaction to the intestinal disease. These include:- Pyoderma gangrenosum- Neutrophilic dermatosis / Sweet syndrome, typically with pustules- Pyodermatitis-pyostomatitis vegetans, a purulent erosive dermatosis characterised by snail-track ulcers- Erythema multiforme- Erythema nodosum- Acneiform eruptions including nodulocystic acne, hidradenitis suppurativa and folliculitis- Palisaded neutrophilic and granulomatous dermatitis- Necrotizing and granulomatous small vessel vasculitis.

According to the NICE guidelines, the frequency of stool passage is considered constipation when two or more of the following findings are present: Fewer than 3 stools a week, large hard stools, stools that resemble rabbit droppings| symptoms associated with defecation including distress, bleeding or straining| a history of previous episodes of a precious/current anal fissure. The child in the scenario fails to meet the criteria, and has no evidence of impacted faeces on examination. The best course of action is to encourage the parents to give the child more water to prevent dehydration, and feed the child a fibre rich diet including fruits, vegetables and high fibre bread.

Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts which normally allow bile to drain from the gallbladder. Early cholangiographic changes can include fine or deep ulcerations of the common bile duct. As PSC progresses, segmental fibrosis develops within the bile ducts, with saccular dilatation of the normal areas between them, leading to the typical beads-on-a-string appearance seen on cholangiography. Although these strictures can be found anywhere on the biliary tree, the intrahepatic and extrahepatic bile ducts are simultaneously involved in the vast majority of cases.

Gastrointestinal polyps are common in children and may result in intussusception due to polyp traction. Treatment is usually surgical with enterotomy and removal of the polyp or of a segment of the bowel.

The most probable diagnosis for this patient would be Crohn’s disease.Crohn’s disease:An inflammatory bowel disease which can affect any part of the bowel from the mouth to the anus. Symptoms include abdominal pain, diarrhoea, pyrexia and weight loss. Extra-intestinal manifestations include arthritis, uveitis, fatigue, anaemia and rashes including pyoderma gangrenosum and erythema nodosum.Other options:- Anorexia nervosa is an important diagnosis to consider. There are no indicators in the description that she has a fear of gaining weight or a strong desire to be thin.- Diabetic ketoacidosis is incorrect because there is no polydipsia or polyuria. A patient in DKA is more likely to present with vomiting and not diarrhoea.- Recurrent aphthous stomatitis is not a correct answer because it does not explain all of the symptoms described, only the mouth ulcers.- Ulcerative colitis (UC) is also incorrect. UC is a form of inflammatory bowel disease that causes inflammation in the colon. The main symptom is bloody stools, which is not mentioned as a feature in history.

One of the features of pyloric stenosis is hypochloraemic, hypokalaemic metabolic alkalosis. In emergency settings, capillary blood gas is the easiest and fastest way to establish a sustainable suspicion of pyloric stenosis. However, all tests are useful for the diagnosis of the condition.

Frequent regurgitation of milk and microcytic anaemia is suggestive of a hiatus hernia. The reflux causes regurgitation of milk and frequent ulceration of the lower oesophageal mucosa potentially resulting in blood loss and anaemia. Duodenal atresia usually presents with bilious vomiting and pyloric stenosis presents with projectile vomiting. Alpha 1 antitrypsin deficiency and cystic fibrosis usually do not present with vomiting.

Bulimia nervosa is a condition in which a person is involved in binge eating and then purging. This patient has swollen parotid glands. The glands swell in order to increase saliva production so that the saliva lost in the vomiting is compensated. This patient also has thickened calluses on the back of her hand. This is known as Russell’s sign. This occurs because of putting fingers in the mouth again and again to induce the gag reflex and vomit. The knuckles get inflamed in the process after coming in contact with the teeth multiple times.

Based on the clinical scenario, the most probable diagnosis is Wilson’s disease. Elevated serum ceruloplasmin levels can confirm the diagnosis.Serum ceruloplasminWilson’s disease causes reduced binding of copper to ceruloplasmin, which is the body’s primary copper carrying protein. As a result, copper cannot be excreted into the bile. Copper, therefore, builds up in the liver, causing toxicity and is secreted into the bloodstream unbound to ceruloplasmin. This free copper is deposited around the body, especially the brain, eyes and kidneys. The genetic defect means that ceruloplasmin is not released into the bloodstream| therefore, ceruloplasmin is low in Wilson’s disease.Other options:- Microscopic evaluation of the hair is performed in Menke’s disease, which is a disease of copper absorption leading to copper deficiency. This causes kinky hair, failure to thrive and neurological symptoms (such as hypotonia).- Magnetic resonance imaging (MRI) scan of the brain: An MRI brain may show features of Wilson’s disease (especially in the basal ganglia), but it is not diagnostic.- Serum ferritin: Serum ferritin becomes high in haemochromatosis. This classically causes cirrhosis, bronzing of the skin, cardiomyopathy and diabetes.- Ultrasound scan of the abdomen: While it is useful in any case of hepatomegaly| it is not going to provide the diagnosis in this case.

Maternal smoking is one of the most significant risk factors for pyloric stenosis.Remember the three Ps for Pyloric Stenosis:P – palpable massP – peristalsisP – projectile vomiting

Hirschsprung’s disease is characterized by congenital absence of the autonomic plexus (Meissner’s and Auerbach’s plexus) in the intestinal wall. Usually limited to the distal colon, it can occasionally involve the entire colon or even the small bowel. There is abnormal or absent peristalsis in the affected segment, resulting in continuous spasm of smooth muscle and partial/complete obstruction. This causes accumulation of intestinal contents and dilatation of proximal segment. Skip lesions are highly uncommon. This disease is seen early in life with 15% patients presenting in first month, 60% by 1 year of age and 85% by the age of 4 years. Symptoms include severe and complete constipation, abdominal distension and vomiting. Patients with involvement of ultra-short segments might have mild constipation with intervening diarrhoea. In older children, symptoms include failure to thrive, anorexia, and lack of an urge to defecate. On examination, an empty rectum is revealed with stool palpable high up in the colon. If not diagnosed in time, it can lead to Hirschsprung’s enterocolitis (toxic megacolon), which can be fulminant and lead to death. Diagnosis involves a barium enema or a rectal suction biopsy. Barium enema shows a transition in diameter between the dilated, normal colon proximal to the narrowed, affected distal segment. It is to be noted that barium enema should be done without prior preparation, which can dilate the abnormal segment, leading to a false-negative result. A 24-hour post-evacuation film can be obtained in the neonatal period – if the colon is still filled with barium, there is a high likelihood of Hirschsprung’s disease. Full-thickness rectal biopsy is diagnostic by showing the absence of ganglion cells. Acetylcholinesterase staining can be done to highlight the enlarged nerve trunks. Abnormal innervation can also be demonstrated by rectal manometry.

The elemental diet is a medically supervised, sole nutrition dietary management given to individuals with moderate to severe impaired gastrointestinal function for 14-21 days.The diet consists of macronutrients broken down into their elemental form requiring little to no digestive functionality allowing time for the gut to rest. Elemental formulations are believed to be entirely absorbed within the first few feet of small intestine.

Celiac disease is classified as a Type IV hypersensitivity mediated by T-cell response. Negatively charged gliadin has been shown to induce interleukin 15 in the enteric epithelial cells, stimulating the proliferation of the natural killer cells and intraepithelial lymphocytes to express NK-G2D, a marker for natural killer T lymphocytes.

The patient is most likely suffering from obstructive jaundice. Ultrasound of the abdomen is the superior diagnostic tool in detecting and assessing biliary system obstruction, because it is easy, available, accurate and non-invasive.