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.

The most likely causative organism for the symptoms of this child is Giardia lamblia.Giardiasis results in fat malabsorption thus giving rise to greasy stools. It is resistant to chlorination, hence has a risk of transfer in swimming pools.World Health Organisation definitions- Diarrhoea: > 3 loose or watery stool per day- Acute diarrhoea < 14 days- Chronic diarrhoea > 14 daysConditions that usually present as acute diarrhoea:- Gastroenteritis: It may be accompanied by abdominal pain or nausea/vomiting.- Antibiotic therapy: Can occur following antibiotic therapy, especially common with broad spectrum antibiotics.Conditions that usually present as chronic diarrhoea:- Irritable bowel syndrome: It is a very common disease.The most consistent features are abdominal pain, bloating and change in bowel habit. Patients may be divided into those with diarrhoea predominant IBS and those with constipation-predominant IBS.Features such as lethargy, nausea, backache and bladder symptoms may also be present in these patients.- Ulcerative colitis: It presents as bloody diarrhoea. Patients can also present with crampy abdominal pain and weight loss. Faecal urgency and tenesmus may be seen.- Crohn’s disease: It is also associated with crampy abdominal pains and diarrhoea. Bloody diarrhoea less common than in ulcerative colitis. Other features include malabsorption, mouth ulcers perianal disease and intestinal obstruction – Colorectal cancer: It is very rare in children. The symptoms depend on the site of the lesion but include diarrhoea, rectal bleeding, anaemia and constitutional symptoms like weight loss and anorexia.- Coeliac disease: In children, it may present with failure to thrive, diarrhoea and abdominal distension.Other conditions associated with diarrhoea include thyrotoxicosis, laxative abuse, appendicitis, and radiation enteritis.

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.

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.

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.

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.

Laxatives have been shown to be beneficial in the treatment of chronic childhood constipation. Studies have shown that polyethylene glycol, mineral oil, magnesium hydroxide, and lactulose are effective and can be used for a prolonged periods without risk.

A minority of affected individuals may experience severe liver failure. This happens most frequently in people with Wilson’s disease during adolescence and more commonly in women. These individuals may rapidly develop signs and symptoms of liver disease, often associated with anaemia due to breakdown of red blood cells (haemolysis) and mental confusion. In some patients, liver disease does not reveal itself, and the patient develops neurologic (brain-related) symptoms. Common neurological symptoms of Wilson disease that may appear and progress with time include tremor, involuntary movements, difficulty swallowing (dysphagia), difficulty speaking and poor articulation (dysarthria), lack of coordination, spasticity, dystonic postures, and muscle rigidity. Almost all affected individuals with the neurological symptoms of Wilson’s disease have Kayser-Fleischer rings in their eyes that can be identified by a slit lamp examination.

Based on the clinical scenario, the most probable diagnosis for this patient is pancreatitis.Although rare in childhood, the presence of abdominal pain radiating to the back with shock and tachycardia, and a raised amylase, should raise a suspicion of pancreatitis. Possible causes include trauma, drugs, viral illness, mumps, hyperparathyroidism, hyperlipidaemia and cystic fibrosis. Other options:- Normal LFTs in this patient make hepatitis unlikely. – Gastroenteritis with severe diarrhoea and vomiting may account for the shock and tachycardia, but guarding on abdominal examination and the raised amylase would not be explained by gastroenteritis. – Pregnancy is an important diagnosis to consider in an adolescent with abdominal pain, but the raised amylase and other features point to a diagnosis of pancreatitis.

The baby has duodenal atresia.Presenting symptoms and signs are results of high intestinal obstruction. Duodenal atresia is typically characterized by the onset of vomiting within hours of birth. While vomitus is most often bilious, it may be nonbilious because 15% of defects occur proximal to the ampulla of Vater. Occasionally, infants with duodenal stenosis escape detection of an abnormality and proceed into childhood or, rarely, into adulthood before a partial obstruction is noted. Nevertheless, one should assume any child with bilious vomiting has a proximal GI obstruction until proven otherwise, and further workup should be begun expeditiously.congenital duodenal atresia is one of the more common intestinal anomalies treated by paediatric surgeons, occurring 1 in 2500-5000 live births. In 25-40% of cases, the anomaly is encountered in an infant with trisomy 21 (Down syndrome).

Gastroesophageal reflux occurs in almost all infants, manifesting as wet burps after feeding. The spit-ups appear effortless and not particularly forceful.Infants in whom reflux has caused GERD have additional symptoms, such as irritability, feeding refusal, and/or respiratory symptoms such as chronic recurrent coughing or wheezing and sometimes stridor. Much less commonly, infants have intermittent apnoea or episodes of arching the back and turning the head to one side (Sandifer syndrome). Infants may fail to gain weight appropriately or, less often, lose weight.Incidence of gastroesophageal reflux increases between 2 months and 6 months of age (likely due to an increased volume of liquid at each feeding) and then starts to decrease after 7 months. Gastroesophageal reflux resolves in about 85% of infants by 12 months and in 95% by 18 months.

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.

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.

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).

The clinical picture suggests that the child is severely dehydrated. IV fluid bolus then IV maintenance fluids is the correct option.

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.

Projectile vomiting is the hallmark symptom of hypertrophic pyloric stenosis. It is the most common cause of intestinal obstruction in infancy, which has a male-to-female predominance of 4-5:1. Current management recommendations include ultrasonography for diagnosis, correction of electrolytes, and surgical intervention.

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.

The structure in question is the rectus sheath. This sheath encloses the rectus abdominis muscle and thus, will be encountered by the surgeon.Note:- Midline incision: It is the most common approach to the abdomen. The structures divided during this incision are linea alba, transversalis fascia, extraperitoneal fat, and peritoneum ( with care taken to avoid the falciform ligament above the umbilicus).The bladder can be accessed via an extraperitoneal approach through the space of Retzius.- Paramedian incision: It is an incision that is made parallel to the midline. The structures divided or retracted are anterior rectus sheath, rectus (retracted), posterior rectus sheath, transversalis fascia, extraperitoneal fat, and peritoneum.- Battle incision: It is similar to a paramedian but the rectus is displaced medially (and thus denervated).- Kocher’s incision: It is an incision made under the right subcostal margin, e.g. cholecystectomy (open).- Lanz incision: It is an incision in the right iliac fossa, e.g. appendicectomy.Gridiron incision: It is an oblique incision centred over the McBurney’s point – usually used for appendicectomy (less cosmetically acceptable than LanzPfannenstiel’s incision: It is a transverse suprapubic incision, primarily used to access pelvic organs.McEvedy’s incision: It is a groin incision used for emergency repair strangulated femoral hernia.Rutherford Morrison incision: It provides an extraperitoneal approach to left or right lower quadrants. It provides excellent access to iliac vessels and is the approach of choice for first-time renal transplantation.

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.

Colonic Polyposis and neoplasia are often seen in Cowden Syndrome which is a hamartomatous polyposis syndrome. Patients with Cowden syndrome have an increased risk for colorectal cancer.

The boy needs re-hydration and hydro-electrolytic re-balancing due to fluid losses from the gastroenteritis and subsequent dehydration.

The most common position of the appendix is the retrocecal position.Note: If a retrocecal appendix is difficult to remove, then mobilisation of the right colon significantly improves access.Other options:The various positions of the appendix are:- Retrocecal (74%)- Pelvic (21%)- Postileal- Subcaecal- Paracaecal- Preileal

Breast milk jaundice is thought to be associated with one or more abnormalities in the maternal milk itself. Breast milk jaundice syndrome generally needs no therapy if serum bilirubin concentrations remain below 270 mmol/l in healthy full-term infants. When the serum bilirubin concentration is above 270 mmol/l and rising, temporary interruption of breastfeeding may be indicated.

Hypertrophic villi is a response to chronic irritation by allergic reactions

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.

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.

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.

Crigler-Najjar syndrome is a rare genetic disorder characterized by an inability to properly convert and clear bilirubin from the body.The hallmark finding of Crigler-Najjar syndrome is a persistent yellowing of the skin, mucous membranes and whites of the eyes (jaundice).There are two forms of this disorder: Crigler-Najjar syndrome type I, characterized by a nearly complete lack of enzyme activity and severe, even life-threatening symptoms| and Crigler-Najjar syndrome type II, characterized by partial enzyme activity and milder symptoms. Both forms are inherited as autosomal recessive traits and are caused by errors or disruptions (mutations) of the UGT1A1 gene.The symptoms of Crigler-Najjar syndrome type I become apparent shortly after birth. Affected infants develop severe, persistent yellowing of the skin, mucous membranes and whites of the eyes (jaundice). These symptoms persist after the first three weeks of life.Infants are at risk for developing kernicterus, also known as bilirubin encephalopathy, within the first month of life.Crigler-Najjar syndrome type II is a milder disorder than type I. Affected infants develop jaundice, which increases during times when an infant is sick (concurrent illness), has not eaten for an extended period (prolonged fasting) or is under general anaesthesia. Some people have not been diagnosed until they are adults. Kernicterus is rare in Crigler-Najjar syndrome type II, but can occur especially when an affected individual is sick, not eating or under anaesthesia

Jaundice in a new-born on the day of delivery is most likely due to Rh incompatibility. This occurs when the mother is Rh-negative and the baby is Rh-positive. Antibodies in the mother against the Rh factor in the baby will destroy the red blood cells in the baby, increasing the bilirubin in the blood. Breast milk jaundice and Galactosemia do not occur immediately after birth, and congenital rubella syndrome and formula feeding does not cause jaundice in babies.