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.

Case control studies are observational studies which retrospectively determine whether a patient might have been exposed to a risk factor for a certain disease, as compared to a control group from the general population. They can be used for a range of outcomes as well as rare diseases. One of the biggest problems with this type of study is recall bias. Research subjects may selectively remember factors that are more predictive of the disease outcome when compared to the control group. All studies should have prior power calculations before the study commences.

The most probable diagnosis for this patient would be congenital hypertrophic pyloric stenosis.Congenital Hypertrophic Pyloric Stenosis (CHPS):Pyloric stenosis should be ruled out in any baby who presents with a long-term history of vomiting and failure to thrive. Infants typically present with projectile, non-bilious vomiting and are said to be hungry and wanting to feed despite poor weight gain. A blood gas would be helpful in this instance, although the diagnosis can be made more accurately by observing the stenosis during ultrasound. Many infants have symptoms of gastroesophageal reflux disease, although only a small minority are unable to gain weight adequately. A UTI in infants can present with non-specific symptoms, but they might have a fever and can show poor feeding. Malrotation will present with bilious vomiting.The definitive surgical management is the Ramsteadt’s pyloromyotomy.

Diarrhoea is defined as having three or more loose or liquid stools per day, or as having more stools than is normal for that person. Severe diarrhoea, causing fluid loss and loss of bicarbonate, will result in marked dehydration and metabolic acidosis.

Topical benzoyl peroxide is used for the treatment of mild to moderate acne vulgaris. It is actually a peeling agent and it clears the pores and reduces the bacterial cell count.

Age (years) Respiratory rate (per minute) Heart rate (per minute) Systolic blood pressure12 15-20 60-100 100-120Adapted from Advanced Paediatric Life Support Manual

Peutz-Jeghers syndrome is an autosomal dominant genetic disease. It presents with hyperpigmentation patches on the oral mucosa, lips, palm and soles, and nasal alae. It also presents with hamartomatous polyps in the gut, hence the fresh blood in this particular case.

Severe cyanotic heart diseases such as pulmonary stenosis, transposition of the great vessels, hypoplastic left heart syndrome and truncus arteriosus all run the risk of a poor prognosis for a neonate. To continue the supply of oxygen the ductus arteriosus must be kept patent. This can be done with the immediate administration of Prostaglandin E1 as a temporary measure until a surgical intervention such as an atrial septostomy can be done. The closure of the duct can subsequently be initiated with the administration of indomethacin and oxygen.

The most probable cause for chronic parotitis in this patient would be HIV infection.Rationale:Chronic infectious parotitis is relatively uncommon in children. While mycobacterial infection can result in chronic parotitis, HIV is a relatively more common cause. The presentation should always prompt an HIV test. Other options:- While mumps is the most common cause of acute viral parotitis, the chronic nature of the boy’s presentation rules it out. – Acute bacterial parotitis is usually unilateral and is warm and tender to touch.

Retinopathy of prematurity affects infants born early, and is due to the abnormal growth of retinal vasculature as opposed to vascular occlusion often see in adults. Though most babies with ROP can see normally, the most significant complication of ROP Is retinal detachment which can lead to blindness. Other structures in the eye such as the optic nerve or the fovea however, are not affected. Children may develop nystagmus as a result of poor sight in the affected eye(s).

The clinical scenario presented is highly suggestive of vitamin C deficiency (Scurvy).Vitamin C is found in citrus fruits, tomatoes, potatoes, Brussel sprouts, cauliflower, broccoli, cabbage and spinach. Deficiency leads to impaired collagen synthesis and disordered connective tissue. Scurvy is associated with severe malnutrition as well as drug and alcohol abuse, and those living in poverty with limited access to fruits and vegetables.Symptoms and signs include:- Follicular hyperkeratosis and perifollicular haemorrhage- Ecchymosis- Gingivitis with bleeding and receding gums- Sjogren’s syndrome- Arthralgia- Oedema- Impaired wound healing- Generalised symptoms such as weakness, malaise, anorexia and depression

Patent ductus arteriosus is a heart defect that occurs in around 50% of the preterm or low birth weight infants. It is characterized by the failure of the fetal ductus arteriosus to close after birth. There are certain risk factors which predispose an infant to a patent ductus arteriosus. The most important risk factor is trisomy 21 or Down’s syndrome, which is associated with multiple cardiac defects. Other factors are congenital rubella syndrome, birth at high altitudes, and female gender.

Breslow thickness is measured from the top of the granular layer of the epidermis (or, if the surface is ulcerated, from the base of the ulcer) to the deepest invasive cell across the broad base of the tumour (dermal/subcutaneous) as described by Breslow.Margins of excision-Related to Breslow thicknessLesions 0-1mm thick – 1cmLesions 1-2mm thick – 1- 2cm (Depending upon site and pathological features)Lesions 2-4mm thick – 2-3 cm (Depending upon site and pathological features)Lesions >4 mm thick – 3cmMarsden J et al Revised UK guidelines for management of Melanoma. Br J Dermatol 2010 163:238-256.

In the first week after birth, it is normal for the baby to lose weight and then gain it again. Therefore, regular child care should be maintained.

Bernard- Soulier Syndrome results from a deficiency of platelet glycoprotein protein Ib, which mediates the initial interaction of platelets with the subendothelial components via the von Willebrand protein. It is a rare but severe bleeding disorder. Platelets do not aggregate to ristocetin. The platelet count is low, but, characteristically, the platelets are large, often the size of red blood cells, and may be missed on complete blood counts because most automatic counters do not count them as platelets.

Penetrance is defined as the percentage of individuals having a particular mutation or genotype who exhibit clinical signs or phenotype of the associated disorder or genotype.Gaucher disease is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

A supracondylar humerus fracture is a fracture of the distal humerus just above the elbow joint. The fracture is usually transverse or oblique and above the medial and lateral condyles and epicondyles. This fracture pattern is relatively rare in adults, but is the most common type of elbow fracture in children. They are historically associated with morbidity due to malunion, neurovascular complications, and compartment syndrome. Important arteries and nerves (median nerve, radial nerve, brachial artery, and ulnar nerve) are located at the supracondylar area and can give rise to complications if these structures are injured. Most vulnerable structure to get damaged is Median Nerve. Damage/occlusion of the brachial artery is the cause of an absent radial pulse.

Fanconi syndrome is a rare disorder characterized by defective proximal renal tubular reabsorption, which leads to excessive excretion of potassium, phosphate, uric acid, bicarbonates, glucose, and certain amino acids in the urine. Loss of potassium in the urine leads to hypokalaemia, while the loss of phosphate may lead to hypophosphatemic rickets. The overall impact is the failure to thrive and growth retardation.

Crossover trials are characterized by the switching of study participants throughout the treatment groups, keeping a random order of switching. This randomization is important to determine any carry-over effect of different treatment modalities. The benefit of this study is the evaluation of the efficacy of various short-term treatment options for the relief of chronic conditions. The washout period is small in this type of study. Crossover studies are more efficient than the parallel studies, but they should be used according to the treatment options and outcomes.

Answer: Acute Epstein Barr virus infectionThe Epstein-Barr virus is one of eight known human herpesvirus types in the herpes family, and is one of the most common viruses in humans. Infection with Epstein-Barr virus (EBV) is common and usually occurs in childhood or early adulthood.EBV is the cause of infectious mononucleosis, an illness associated with symptoms and signs like:fever,fatigue,swollen tonsils,headache, andsweats,sore throat,swollen lymph nodes in the neck, andsometimes an enlarged spleen.Although EBV can cause mononucleosis, not everyone infected with the virus will get mononucleosis. White blood cells called B cells are the primary targets of EBV infection.Petechiae on the palate are characteristic of streptococcal pharyngitis but also can be seen in Epstein-Barr virus infection, Arcanobacterium haemolyticum pharyngitis, rubella, roseola, viral haemorrhagic fevers, thrombocytopenia, and palatal trauma.

The first sign of pubarche in females is breast-bud development (thelarche).This begins between the ages of 9 and 12 years and continues to 12-18 years. Pubic hair growth occurs next (said to occur in stage 3), at ages 9-14 years, and is complete at 12-16 years. Menarche occurs relatively late in stage 4 (age 11-15 years) and is associated with a deceleration in growth. The peak height velocity is reached earlier (10-13 years) and growth is completed much earlier than in boys.

The baby may have hydrocephalus and no surgery can be done until it is excluded.Cranial sonography is an important part of neonatal care in general, and high-risk and unstable premature infants, in particular. It allows rapid evaluation of infants in the intensive care units without the need for sedation and with virtually no risk. Expectedly, sonography represents an ideal imaging modality in neonates due to its portability, lower cost, speed, and lack of ionizing radiations. Although there are numerous indications for cranial sonography, it appears to be most useful for detection and follow-up of intracranial haemorrhage, hydrocephalus, and periventricular leukomalacia (PVL).

Cytomegalovirus (CMV) is the most frequent cause of congenital infection worldwide, with an estimated incidence in developed countries of 0.6-0.7% of all live births.The clinical spectrum of congenital CMV infection varies widely, from the complete absence of signs of infection (asymptomatic infection) to potentially life-threatening disseminated disease. At birth, 85-90% of infected infants are asymptomatic, and 10-15% present with clinical apparent infection (symptomatic disease).The presentation in this latter group is a continuum of disease expression whose more common findings are petechiae, jaundice, hepatomegaly, splenomegaly, microcephaly, and other neurologic signs.

Persistent pulmonary hypertension of the new-born is secondary to the failure of normal circulatory transition at birth, leading to an abnormally high pulmonary vascular resistance. This elevated resistance causes right-to-left shunting of blood and hypoxemia. It can be caused by parenchymal lung diseases (meconium aspiration syndrome, pneumonia or ARDS), lung hypoplasia (like occurring in oligohydramnios or diaphragmatic hernia), or it can be idiopathic. Other possible causes include maternal indomethacin use, group B streptococcal septicaemia, and high-pressure ventilation. Duct dependent congenital heart disease does not lead to persistent pulmonary hypertension.

Insufficient surfactant production in premature infants leads to respiratory distress syndrome or surfactant deficient lung disease (SDLD), characterized by structurally immature lungs. There are many risk factors of this disease, some of them include male gender, caesarean section, infants of diabetic mothers, being the second born of the premature twins, perinatal asphyxia, sepsis, and hypothermia. Maternal hypertension is not a recognized risk factor for respiratory distress syndrome; instead, pregnancy-induced hypertension and chronic maternal hypertension are the protective factors against this disease.

Mumps presents with a prodromal phase of general malaise and fever. On examination there is usually painful parotid swelling which has high chances of becoming bilateral. In OM with effusion there are no signs of infection and the only symptom is usually hearing loss. Acute otitis externa produces otalgia as well as ear discharge and itching. Acute OM produces otalgia and specific findings upon otoscopy. In acute mastoiditis the patient experiences ear discharge, otalgia, headache, hearing loss and other general signs of inflammation.

The organisms most likely to cause post-splenectomy sepsis include:- Streptococcus pneumoniae- Haemophilus influenzae- MeningococciEncapsulated organisms carry the most significant pathogenic risk following splenectomy. Hyposplenism:It may complicate certain medical conditions where splenic atrophy occurs or maybe the result of medical intervention such as splenic artery embolization and splenectomy for trauma. The diagnosis of hyposplenism is difficult, and while there may be peripheral markers of the splenectomised state (e.g. Howell-Jolly bodies), these are neither 100% sensitive or specific. The most sensitive test is a radionucleotide labelled red cell scan.It dramatically increases the risk of post-splenectomy sepsis, particularly with encapsulated organisms. Since these organisms may be opsonized, but this then goes undetected at an immunological level due to loss of the spleen. For this reason, individuals are recommended to be vaccinated and have antibiotic prophylaxis.Key recommendations:- All those with hyposplenism or prior to an elective splenectomy should receive pneumococcal, Haemophilus type b and meningococcal type C vaccines. These should be administered two weeks before or two weeks following splenectomy. The vaccine schedule for meningococcal disease primarily consists of a dose of Men C and Hib at two weeks and then a dose of the MenACWY vaccine one month later. Those aged under two may require a booster at two years. A dose of pneumococcal polyvalent polysaccharide vaccine (PPV) is given at two weeks. A conjugate vaccine (PCV) is offered to young children. The PCV is more immunogenic but covers fewer serotypes. Boosting PPV is either guided by serological measurements (where available) or by routine boosting doses at five-yearly intervals.Annual influenza vaccination is recommended in all cases- Antibiotic prophylaxis is offered to all. The risk of post-splenectomy sepsis is highest immediately following splenectomy. Individuals with an inadequate response to pneumococcal vaccination are another high-risk group. High-risk individuals should be counselled to take penicillin or macrolide prophylaxis. Those at low risk may choose to discontinue therapy. All patients should be advised about taking antibiotics early in the case of intercurrent infections.- Asplenic individuals travelling to malaria-endemic areas are at high risk and should have both pharmacological and mechanical protection.

Pulmonary arterial hypertension (PH) is noted in 9 to 35 % of patient with a secundum type ASD. The haemodynamic definition of PH is a mean pulmonary arterial pressure (mPAP) of +-25 mmHg at rest by means of right heart catheterization. In ASD, The findings on physical examination depend on the degree of left-to-right shunt and its hemodynamic consequences, which, in turn, depends on the size of the defect, the diastolic properties of both ventricles, and the relative resistance of the pulmonary and systemic circulations.Blood flow across the atrial septal defect (ASD) does not cause a murmur at the site of the shunt because no substantial pressure gradient exists between the atria. However, ASD with moderate-to-large left-to-right shunts results in increased right ventricular stroke volume across the pulmonary outflow tract creating a crescendo-decrescendo systolic ejection murmur. This murmur is heard in the second intercostal space at the upper left sternal border.Patients with large left-to-right shunts often have a rumbling mid-diastolic murmur at the lower left sternal border because of increased flow across the tricuspid valve.ASD is an acyanotic lesion. Thus, the patient should be normally saturated. In the rare case of severe pulmonary arterial hypertension, atrial shunt reversal (Eisenmenger syndrome) may occur, leading to cyanosis and clubbing

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.

The murmur and thrill indicate a right outflow tract murmur, coupled with the right ventricular heave suggests right ventricular hypertrophy. The VSD would not have been amenable to surgery due to the child’s size/weight and so instead would have been palliated with a PA band. As the child grows, this band progressively restricts pulmonary blood flow until the left to right shunt has reversed. Then it is time for the band to be removed and the VSD to be closed.Pulmonary atresia is a cyanotic condition, which may be palliated with an arterial duct stent. This answer is incorrect as the stent placement would not require a midline sternotomy and would give a continuous machinery type murmur. Pulmonary stenosis with PDA ligation is incorrect. The murmur, thrill, and heave all match a pulmonary stenosis but in the absence of an additional shunt lesion the child would not be cyanosed.