The diagnosis of a post-splenectomy/hyposplenism blood picture can be made reliably by identifying Howell Jolly bodies in routine Wright-Giemsa stained blood and target cells. These are round basophilic bodies in red blood cells that represent residual nuclear material from marrow nucleated red cell precursors that are usually culled out by the spleen.These do not occur in individuals with normally functioning splenic tissue and their presence indicates either 1) an asplenic state or 2) hypofunctioning splenic tissue as might be seen in a patient with late-stage sickle cell anaemia. Their presence in an individual with splenomegaly leads to a narrow differential diagnosis and their absence in a splenectomised individual indicates accessory splenic Heinz bodies and poikilocytosis typically increase in a splenectomised individual and care must be taken not to overdiagnose haemolysis in such an individual.

The azygos lobe is usually well seen on the chest radiograph, where it is limited by the azygos fissure, a fine, convex (relative to the mediastinum) line that crosses the apex of the right lung.

This is a case of an anaphylactic reaction that requires immediate intervention. IM adrenaline dose for 6-12 year old children is 300 micrograms IM.

Immediate needle decompression of pneumoperitoneum is necessary to avoid tension pneumoperitoneum. Air reduction enema is the main stay of treatment for intussusception and is successful in around 90% of cases. A serious potential risk of this procedure is perforation of the colon and a pneumoperitoneum, leading to rapid distension of the abdomen and splinting of the diaphragm.

Many of the symptoms favour an epilepsy diagnosis: uncontrollable jerking of the limbs and a loss of consciousness. A 24-hour EEG is used to diagnose epilepsy.

Familial/inherited short stature is the most likely and commonest factor resulting in short stature among the children. Klinefelter syndrome is characterised by tall stature, widely spaces nipples and infertility. Other factors include congenital heart disease, maternal deprivation and diabetes mellitus but these are the rare causes.

Vaccines should not be given to a feverish child.

Internal abdominal bleeding is most probably the cause of the child’s shock, especially unresponsive to fluid boluses.

Sepsis can be described as a condition in which there is a dysregulated inflammatory response to an infection. In the case of neonates, sepsis can be life threatening and may present with respiratory distress more than 4 hours after birth, shock, seizures, and multi organ failure. Risk factors that further point to sepsis include prolonged rupture of maternal membranes for more than 24 hours before birth, a history of a maternal fever during labour, or parenteral antibiotic treatment given to the mother for a suspected or confirmed bacterial infection.

The post-ingestion plasma level, which is required in order to guide the treatment, reaches a peak at 4 hours. Levels requiring antidote (N-acetyl cysteine) include: 100 mcg per ml at 4 hours, 35 mcg per ml at 10 hours and 25 mcg per ml at 12 hours. These levels are in conjunction with the levels recorded and they should all be put down on a treatment nomogram.

Based on the clinical scenario, the boy is going through normal pubertal changes.In the 3 years before puberty, low pulsatile LH levels become detectable during sleep. LH and FSH are produced in the anterior pituitary and released due to pulsatile gonadotrophin-releasing hormone (GnRH) secreted by the hypothalamus. There is an increase in the amplitude and frequency of LH secretion as puberty approaches, which causes enlargement of the gonads. In boys, the testicles produce testosterone, and in girls, the ovaries produce oestradiol and ovarian androgens, which, with the adrenal androgens, produce secondary sexual characteristics.Note:The average age at onset of puberty is 11 years in girls. The first sign is breast bud development, followed by the appearance of pubic hair 6-12 months later. Menarche usually occurs 2-2.5 years after breast bud development. Peak height velocity in girls occurs at breast stage 2-3 and virtually always precedes menarche. The onset of puberty in boys is at 11.5 years. The first sign is testicular enlargement (>3 ml) and thinning of the scrotum. This is followed by the pigmentation of the scrotum and growth of the penis, and pubic hair follows. Peak height velocity (growth spurt) is two years later in boys than in girls and occurs at testicular stage 4-5 (i.e. testicular volume 10-12 ml), which is around 13-14 years of age. Breast enlargement occurs in 40-60% of boys (rarely, significant enough to cause social embarrassment in 10%) and is a result of oestradiol produced by the metabolism of testosterone. It usually resolves within three years. During puberty, elongation of the eye often occurs, causing short-sightedness.

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.

Erythema infectiosum is an acute viral illness caused by Parvovirus B19. It is usually a mild flu-like illness and produces a maculopapular rash, appearing initially on the cheeks and then spreading towards extremities. The rash usually spares the palms and soles and gives a slapped appearance to the cheeks. It can be described as having a fishnet appearance on the body.

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.

Osteochondromas, or osteocartilaginous exostoses, are the most common benign bone tumours, and tend to appear near the ends of long bones. The overgrowth can occur in any bone where cartilage forms bone, and they are capped by cartilage. They are most common in people between the ages of 10-20 years old.

Port-wine stains are a type of vascular birthmark caused by the abnormal development of capillaries in the skin. These pinkish-purplish discolorations present at birth and are associated with medical conditions such as Sturge-Weber syndrome, a neurocutaneous disorder involving the leptomeninges. Port wine stains are therefore associated with epilepsy, glaucoma or intellectual disability common in Sturge-Weber syndrome. Additional complications of Port wine stains include a loss of function if near the eye or mouth due to hypertrophy, or glaucoma if near the eyelid.

The next step in the management of this patient is starting a normal saline fluid bolus, following which we should send samples for blood culture, lactate and C-reactive protein. The patient is probably a case of anorexia nervosa (AN).Note:Children with AN are at higher risk of developing infections, and this needs to be considered in this case. Patients with AN may not respond in the usual fashion to sepsis as they may not mount a fever in response to infection. Hypoglycaemia (especially when severe or persistent despite correction) should raise the alarm for an infection as should tachycardia and cool peripheries. Children with severe AN are more likely to be bradycardic. Therefore, a tachycardia should cause the clinician to consider that another process is going on.Other options:- Correcting electrolyte abnormalities is, of course, very important. However, while these are awaited, one needs to consider that this patient is septic and managed accordingly. Children with anorexia nervosa (AN) may have a whole host of electrolyte abnormalities, some of which can be treated with oral or nutritional supplementation although sometimes intravenous correction is required. Electrolytes need to be checked frequently during admission because of the risk of refeeding syndrome, and dietetic input is required to advise on appropriate starting intake.- While maintenance fluids like dextrose are likely to be needed in this case, consideration needs to be given to the underlying cause of the hypoglycaemia. As the sugar has come up following a glucose bolus, a 10% dextrose infusion would be excessive.- An ECG should form a part of any assessment of a child with AN. In this case, it would not be the first thing; however, as part of the acute management of this child, cardiac monitoring should be commenced. One would usually expect a child with AN to be bradycardic so a tachycardia should raise suspicion that another process is going on.- Dietary input will be vital for this child’s ongoing management. However, their acute issues take precedence in this case. Nevertheless, a dietician should be informed and involved from an early stage.

Angio-oedema, is the rapid swelling of the skin, mucosa and submucosal tissues. The underlying mechanism typically involves histamine or bradykinin. The version related to histamine is to due an allergic reaction to agents such as insect bites, food, or medications. The version related to bradykinin may occur due to an inherited C1 esterase inhibitor deficiency, medications e.g. angiotensin converting enzyme inhibitors, or a lymphoproliferative disorder.

The most probable diagnosis for this patient’s symptoms is psoriasis. Psoriasis:Chronic plaque psoriasis is characterised by pinkish-red hyperkeratotic plaques, which occur mainly on extensor surfaces such as knees and elbows. The lower back, ears and scalp can also be involved. Koebner phenomenon: Psoriasis typically exhibits this phenomenon where new plaques of psoriasis occur particularly at sites of skin trauma. Diagnosis:Skin biopsy of psoriatic plaques reveals acanthosis and parakeratosis, reflecting increased skin turnover. Capillary dilatation within the dermis also occurs, surrounded by a mixed neutrophilic and lymphohistiocytic perivascular infiltrate.

Odds ratios are best described as the odds of an event in one group divided by the odds of the event in another. They form an alternative to the relative risk in case-control studies and are close to the relative risk when events are rare. The odds are the number of the event divided by the number without the event, which is less intuitive than the risk, which is the number with the event divided by the total. Odds ratios are therefore less intuitive than relative risks. Logistic regression analysis outputs variable coefficients which are the log of the odds ratio.

Haemophilia A has an X-linked recessive pattern of inheritance, meaning that is a 50% chance of having a son with haemophilia and 50% chance of the daughters being carriers of the haemophilia gene.

Heart murmurs are common in healthy infants, children, and adolescents. Although most are not pathologic, a murmur may be the sole manifestation of serious heart disease. Historical elements that suggest pathology include family history of sudden cardiac death or congenital heart disease, in utero exposure to certain medications or alcohol, maternal diabetes mellitus, history of rheumatic fever or Kawasaki disease, and certain genetic disorders. Physical examination should focus on vital signs; age-appropriate exercise capacity; respiratory or gastrointestinal manifestations of congestive heart failure; and a thorough cardiovascular examination, including features of the murmur, assessment of peripheral perfusion, and auscultation over the heart valves. Red flags that increase the likelihood of a pathologic murmur include a holosystolic or diastolic murmur, grade 3 or higher murmur, harsh quality, an abnormal S2, maximal murmur intensity at the upper left sternal border, a systolic click, or increased intensity when the patient stands. Electrocardiography and chest radiography rarely assist in the diagnosis.

The boy suffers from balanitis xerotica obliterans (BXO) which is surgically treated with circumcision and urethral calibration. In fact, the condition is the only true medical indication for circumcision.

Croup is the most common aetiology for hoarseness, cough, and onset of acute stridor in febrile children. Symptoms of coryza may be absent, mild, or marked. The vast majority of children with croup recover without consequences or sequelae.

Injuries to the peroneal nerve can cause numbness, tingling, pain, weakness and foot drop. The branches of the common peroneal nerve innervate and control the muscles in the legs that lift the ankle and toes upward (dorsi flexion).

Haemolytic-uremic syndrome (HUS) is a clinical syndrome characterized by progressive renal failure that is associated with microangiopathic (nonimmune, Coombs-negative) haemolytic anaemia and thrombocytopenia. HUS is the most common cause of acute kidney injury in children. It predominantly occurs in infants and children after prodromal diarrhoea. In summer epidemics, the disease may be related to infectious causes.Bacterial infections may include the following:S dysenteriaeE ColiSalmonella typhiCampylobacter jejuniYersinia pseudotuberculosisNeisseria meningitidisS pneumoniaLegionella pneumophilaMycoplasma speciesRickettsial infections may include Rocky Mountain spotted fever and microtatobiotesViral infections may include the following:Human immunodeficiency virus (HIV)CoxsackievirusEchovirusInfluenza virusEpstein-Barr virusHerpes simplex virusFungal infections can include Aspergillus fumigatus.Vaccinations may include the following:Influenza triple-antigen vaccineTyphoid-paratyphoid A and B (TAB) vaccinePolio vaccinePregnancy-associated HUS occasionally develops as a complication of preeclampsia. Patients may progress to full-blown haemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. Postpartum HUS usually occurs within 3 months of delivery. The prognosis is poor, with a 50-60% mortality rate, and residual renal dysfunction and hypertension occur in most patients.

Pellagra occurs as a result of niacin (vitamin B-3) deficiency. Niacin is required for most cellular processes. Since tryptophan in the diet can be converted to niacin in the body, both of these need to be deficient for pellagra to develop.The classical triad of symptoms is diarrhoea, dermatitis and dementia.The first sign is reddened skin with superficial scaling in areas exposed to sunlight, heat and friction. This may resemble severe sunburn then gradually subsides leaving a dusky brown-red colouration. The rash is usually symmetrical with a clear edge between affected and unaffected skin.

The Five P’s: pain, pulselessness, paraesthesia, paralysis, and pallor, are the most common symptoms of compartment syndrome. However, late signs of the condition include the absence of distal pulses.

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.

ADH primarily acts on the collecting ducts.Other options:- The juxtaglomerular apparatus is the site of renin production.- The proximal tubule conducts isosmotic reabsorption of about 60% of sodium chloride and volume. Most of the glucose, amino acids, potassium and phosphate are absorbed here.- The loop of Henle is the site of 25% of sodium reabsorption. Active Chloride transport provides the basis for the counter current multiplier aiding urinary concentration.- The distal convoluted tubule is impermeable to water and acts via active sodium chloride absorption to dilute urine.