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.

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.

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.

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.

Based on the history and clinical presentation, she most likely has iron toxicity.Iron can cause scarring of the gut mucosa. This explains her pyloric stenosis. This typically occurs at the pylorus as this is where iron tablets tend to pool and cause maximal tissue damage.Other options:- Citalopram: Selective serotonin reuptake inhibitors (SSRIs) ingestion rarely causes serious consequences. It can rarely lead to serotonin syndrome (autonomic instability, mental status change, and increased neuromuscular tone).- Ibuprofen: While it may cause gastritis, ibuprofen does not cause pyloric/intestinal stenosis.- Thyroxine: An overdose of thyroxine will cause features of hyperthyroidism which are not present in the patient in question.- Zinc: High doses of zinc can cause abdominal cramps, nausea, vomiting and diarrhoea.

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.

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 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.

This patient in question is most likely suffering from inflammatory bowel disease, probably ulcerative colitis. The most valuable investigation that can assess the severity and extent of the disease, including the opportunity to obtain biopsies is a colonoscopy.Other options:Barium studies and abdominal x-rays do not give sufficient information. While they can provide indicative evidence, only a colonoscopy-guided biopsy can confirm IBD.Radio-isotope scans will help in identifying a focus such as a Meckel’s diverticulum, and angiography is rarely indicated unless a vascular lesion is suspected of causing the intestinal bleed.

The Green Book guidelines report in an active infection (HBeAg+ and HBsAg+) to give the vaccine as well as immunoglobulin. If antibodies are present it is not active infection (anti-Hbe) and then in that case only the vaccine, and no immunoglobulin, would be given. The presence of HBeAg means a person is infectious and can transmit to other people.

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.

People with Gilbert syndrome have a build-up of unconjugated bilirubin in their blood (unconjugated hyperbilirubinemia). In affected individuals, bilirubin levels fluctuate and very rarely increase to levels that cause jaundice. Gilbert syndrome is usually recognized in adolescence. If people with this condition have episodes of hyperbilirubinemia, these episodes are generally mild and typically occur when the body is under stress, for instance because of dehydration, prolonged periods without food (fasting), illness, vigorous exercise, or menstruation. Some people with Gilbert syndrome also experience abdominal discomfort or tiredness. However, approximately 30 percent of people with Gilbert syndrome have no signs or symptoms of the condition and are discovered only when routine blood tests reveal elevated unconjugated bilirubin levels.

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.

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.

Pale stools suggest obstructive jaundice. Initially, the symptoms of biliary atresia are indistinguishable from those of neonatal jaundice, a usually harmless condition commonly seen in infants. However, infants with biliary atresia develop progressive conjugated jaundice, pale white stools and dark urine.

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.

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.

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.

Pale, bulky, malodorous stools are evidence of fat malabsorption syndrome. The diagnostic test is jejunal biopsy to rule out other differential diagnoses such as celiac disease, giardiasis or Crohn’s disease etc.

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.

The prompt is suggestive of acute appendicitis. The Alvarado score is a clinical scoring system used to determine the likelihood of appendicitis, so this is the correct answer. A score greater than 6 is generally considered at risk for having acute appendicitis. It has 8 different criteria included (symptoms, signs, and lab results) and divides patients into appendicitis unlikely, possible, probable, and definite. The Center Score is a score to access the likelihood that pharyngitis is due to Strep. The Child-Pugh score predicts prognosis in liver cirrhosis. The Glasgow score is two different scores– the Glasgow coma score in trauma, which estimates level of consciousness, essentially, and The Glasgow Imrie Criteria which determines the severity of acute pancreatitis based on 8 lab values. The MELD score predicts the severity of end-stage liver disease.

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disorder characterized by intestinal hamartomatous polyps in association with a distinct pattern of skin and mucosal macular melanin deposition (freckles on the lips, face, palms and soles). Patients with Peutz-Jeghers syndrome have an estimated 15-fold increased risk of developing intestinal cancer compared to the general population.Management: conservative unless complications develop.

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.

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

The gastrocolic reflex is a physiological reflex that involves increase in colonic motility in response to stretch in the stomach and by-products of digestion in the small intestine. It is shown to be uneven in its distribution throughout the colon, with the sigmoid colon affected more than the right side of the colon in terms of a phasic response. Various neuropeptides have been proposed as mediators of this reflex, such as serotonin, neurotensin, cholecystokinin and gastrin.

The signs and symptoms of vitamin D-dependent rickets begin within months after birth, and most are the same for all types of the condition. The weak bones often cause bone pain and delayed growth and have a tendency to fracture. When affected children begin to walk, they may develop abnormally curved (bowed) legs because the bones are too weak to bear weight. Impaired bone development also results in widening of the metaphysis, especially in the knees, wrists, and ribs. Some people with vitamin D-dependent rickets have dental abnormalities such as thin tooth enamel and frequent cavities. Poor muscle tone (hypotonia) and muscle weakness are also common in this condition, and some affected individuals develop seizures.

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.

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.

Fluid replacement therapy should be initiated immediately because the patient is suffering from severe dehydration as shown by the low urine output, the dry mucous membranes and the low skin turgor.