Hassall’s corpuscles are groups of epithelial cells within the thymic medulla. The physical nature of these structures differs between mammalian species. Although Hassall’s corpuscles have been proposed to act in both the removal of apoptotic thymocytes and the maturation of developing thymocytes within the thymus, the function of Hassall’s corpuscles has remained an enigma.

The trisomy 18 syndrome, also known as Edwards syndrome, is a common chromosomal disorder due to the presence of an extra chromosome 18, either full, mosaic trisomy, or partial trisomy 18q. The condition is the second most common autosomal trisomy syndrome after trisomy 21.Currently, most cases of trisomy 18 are prenatally diagnosed, based on screening by maternal age, maternal serum marker screening, or detection of sonographic abnormalities (e.g., increased nuchal translucency thickness, growth retardation, choroid plexus cyst, overlapping of fingers, and congenital heart defects ).The main clinical features represent the clues for the diagnosis in the perinatal period and include prenatal growth deficiency, characteristic craniofacial features (dolichocephaly, short palpebral fissures, micrognathia external anomalies of the ears, and redundant skin at the back of the neck), distinctive hand posture (overriding fingers: index finger overlapping the third and 5th finger overlapping the 4th), nail hypoplasia, short hallux, underdeveloped thumbs, short sternum, and club feet and major malformations (particularly involving the heart).

Pupils are dilated in patients with amitriptyline overdose.Tricyclic antidepressants have a narrow therapeutic index, and thus, small doses can be fatal in children. Deaths from tricyclics are more common than other antidepressants. Bimodal incidence with toddlers (accidental) and teenagers (deliberate) most commonly affected.Symptoms: They occur within 6 hours of ingestion.- Nausea, vomiting, and headache- Elevated body temperature- Agitation, sleepiness, confusion, coma- Dry mouth, blurred vision, urinary retention (anticholinergic)- Dilated pupils- Seizures- Hypotension, tachycardia, conduction disorders, and cardiac arrest- Respiratory depressionManagement:Treatment focuses on supportive care. This includes airway protection, ventilation and oxygenation, intravenous fluids, and cardiac monitoring.Other measures include:- Activated charcoal within 2 hours- Hypotension is treated with IV fluids and adrenaline- Cardiac monitoring- Sodium bicarbonate in acidosis or if there are wide QRS complex (> 100 ms)- Convulsions may require diazepam or lorazepam.

Based on the presentation, the child most probably is suffering from a refractive error.Astigmatism, myopia and high hypermetropia could all cause these symptoms. This child has difficulty in using vision for finer tasks such as reading. Mild to moderate refractive error would not impair the child’s ability to play or even watch television as for the child in question. Note: Refractive error is the most common treatable cause of reduced vision in children all over the world! Other options:- A congenital cataract is rare and retinal dystrophy is even rarer. – Amblyopia would suggest poor vision in only one eye, something that might not cause symptoms in this age group. – Parents or teachers would have probably noticed squint if it was present.

Haemolytic disease of the new-born due to ABO incompatibility is usually less severe than Rh incompatibility. One reason is that fetal RBCs express less of the ABO blood group antigens compared with adult levels. In addition, in contrast to the Rh antigens, the ABO blood group antigens are expressed by a variety of fetal (and adult) tissues, reducing the chances of anti-A and anti-B binding their target antigens on the fetal RBCs.ABO HDN occurs almost exclusively in the offspring of women of blood group O, although reports exist of occasional cases in group A mothers with high‐titre anti‐(group B) IgG

In secretory OM, effusion in the middle ear is present which does not produce any pain to the patient in comparison to acute OM which produces otalgia. The family members are the ones to notice hearing loss as the patient usually is not aware of it. On otoscopy, the features described in the question are prominent. Otitis externa is usually painful and it also produces an itching sensation. Chronic otitis media is painful and may interfere with balance problems. Cholesteatoma is an abnormal cystic growth in the middle ear that usually discharges foul-smelling fluids and as it grows, otalgia can appear.

All the given development milestones are compatible with the given age.

Miliaria is a common skin disease caused by blockage and/or inflammation of eccrine sweat ducts. Miliaria is frequently seen in hot, humid or tropical climates, in patients in the hospital, and in the neonatal period. Miliaria is also known as sweat rash.Based on the level of the sweat duct obstruction, miliaria is divided into three subtypes:- Miliaria crystallina (sudamina), caused by obstruction of the sweat ducts close to the surface of the skin (epidermis)|- Miliaria rubra, caused by obstruction of the sweat ducts deeper in the epidermis|- Miliaria profunda (tropical anhidrosis), the result of sweat leaking into the middle layer of skin (dermis).Miliaria crystallina appears as 1–2 mm superficial clear blisters that easily break. The blisters can look like beads of sweat. There is no inflammation. The blisters are usually seen widely spread on the head, neck, and upper trunk.Miliaria rubra is the most common type of miliaria results in red, 2–4 mm, non-follicular papules and papulovesicles. They are very itchy. Background erythema is often present. In children, miliaria affects the skin folds of the neck, axilla or groin. In adults, miliaria often affects the upper trunk, scalp, neck and flexures, particularly areas of friction with clothing. Miliaria pustulosa is a variant of milia rubra in which there are pustules.Miliaria profunda describes asymptomatic deep papules. The flesh–coloured, 1–3 mm diameter papules usually arise on the trunk and extremities.Mild Topical steroids can be used as a treatment

The first brachial arch (mandibular) gives rise to the mandibular and maxillary processes. Muscles and bones of this process originate within the arch’s mesoderm. The first arch cartilage (Meckel’s) ossifies to form the incus and malleus of the middle ear. Its perichondrium gives rise to he sphenomandibular ligament and through intermembraneous ossification after the mandible forms, the rest of the cartilage disappears. Muscles of the first arch include: mylohyoid, tensor tympany and palati, temporalis, masseter and lateral pterygoids and the anterior belly of the epigastric. This first arch is supplied by the trigeminal nerve.

Erythema multiforme lesions typically heal without scarring. Other options:- In erythema multiforme, lesions are typically symmetrical and acral, i.e. on the hands, feet and limbs. – HSV is a common cause of erythema multiforme in children, accounting for at least 50% of cases| the lesions typically have damaged skin in the centre and are dusky and bullous (in contrast to urticaria, where the centre of the lesion is normal).

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disease. The Lisch nodule represents one of the most common NF1 ocular manifestations.NF1 is caused by a genetic mutation which can cause tumours to grow on nerve endings| these cutaneous neurofibromas are benign tumours which grow on the skin, often first appearing during the hormonal changes that occur in teenage years. They vary in size and can appear anywhere on the body. The number of neurofibromas present differs greatly between individuals and over a lifetime Café au lait spots (coffee coloured birthmarks) are often the first and most common sign of NF1, and these are often found at birth and are usually evident by 2 years of age.Other features of NF1 can include Lisch nodules of the iris (small pigmentation in the iris which causes no disturbance to vision), skin-fold freckling (freckling/pigmentation in the groyne and armpits), plexiform neurofibromas (or sub cutaneous neurofibromas) which are diffuse tumours that grow along a nerve and are found in at least 25 % of people with NF1, optic gliomas (tumour of the optic nerve), and skeletal complications including pseudarthrosis and scoliosis. Macrocephaly (large head size) is also common, and short stature is found in around a third of people with NF1. Rare complications include a risk of malignancy, organs being compromised by neurofibromas, seizures, and hypertension.

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.

Key observations in the results:

1. Oxygen Saturation Step-Up:
   • There is a significant step-up in oxygen saturation from the right ventricle (72%) to the pulmonary artery (86%). This suggests the presence of left-to-right shunting of blood.
2. Pressure Differences:
   • The pressure in the pulmonary artery is elevated (53/13 mmHg), indicating pulmonary hypertension.

Differential Diagnosis:

1. Patent Ductus Arteriosus (PDA):
   • PDA can cause increased pulmonary blood flow, leading to a step-up in oxygen saturation in the pulmonary artery. The pulmonary artery pressures can also be elevated due to increased blood flow.
2. Primary Pulmonary Hypertension:
   • Typically presents with elevated pulmonary pressures but does not usually show a step-up in oxygen saturation.
3. Pulmonary Stenosis:
   • Would result in elevated right ventricular pressure but would not explain the step-up in oxygen saturation.
4. Septum Primum Atrial Septal Defect (ASD):
   • Would result in a step-up in oxygen saturation from the right atrium to the right ventricle, not between the right ventricle and pulmonary artery.
5. Tetralogy of Fallot:
   • Characterized by right ventricular outflow tract obstruction, VSD, right ventricular hypertrophy, and an overriding aorta. Oxygen saturation levels would typically be lower in the systemic circulation.

In boys, the first manifestation of puberty is testicular enlargement| the normal age for initial signs of puberty is 9 to 14 years in males. Pubic hair in boys generally appears 18 to 24 months after the onset of testicular growth and is often conceived as the initial marker of sexual maturation by male adolescents.

One of the options of Psoriasis treatment is vitamin D analogues i.e. calcipotriol. Acne is exacerbated by steroids. Erythema nodosum can be caused by various diseases and the treatment of the primary condition resolves the symptoms. Lipomas requires surgery, whereas Steven-Johnson syndrome requires use of steroids and eliminating the culprit drug, which is one of the most common causes.

Most healthy infants and children grow predictably, following a typical pattern of progression in weight, length, and head circumference. Normal human growth is pulsatile| periods of rapid growth (growth spurts) are separated by periods of no measurable growth Growth hormone levels and responsiveness’ develop in late infancy, increase during childhood and peak during puberty.Typical milestones — General guidelines regarding length or height gain during infancy and childhood include the following:- The average length at birth for a term infant is 20 inches (50 cm)- Infants grow 10 inches (25 cm) during the first year of life- Toddlers grow 4 inches (10 cm) between 12 and 24 months, 3 inches (7.5 cm) between 24 and 36 months, and 3 inches (7.5 cm) between 36 and 48 months- Children reach one-half of their adult height by 24 to 30 months- Children grow 2 inches per year (5 cm per year) between age four years and puberty- There is a normal deceleration of height velocity before the pubertal growth spurt.Growth continues past pubertal growth spurt as there is increase in spinal length.

According to NICE guidelines:Do not offer lithium to women who are planning a pregnancy or pregnant, unless antipsychotic medication has not been effective.If antipsychotic medication has not been effective and lithium is offered to a woman who is planning a pregnancy or pregnant, ensure:the woman knows that there is a risk of fetal heart malformations when lithium is taken in the first trimester, but the size of the risk is uncertain. Lithium levels may be high in breast milk with a risk of toxicity for the baby.If a woman taking lithium becomes pregnant, consider stopping the drug gradually over 4 weeks if she is well. Explain to her that:stopping the medication may not remove the risk of fetal heart malformations and there is a risk of relapse, particularly in the postnatal period, if she has bipolar disorder.If a woman taking lithium becomes pregnant and is not well or is at high risk of relapse, consider:switching gradually to an antipsychotic or stopping lithium and restarting it in the second trimester (if the woman is not planning to breastfeed and her symptoms have responded better to lithium than to other drugs in the past) or continuing with lithium if she is at high risk of relapse and an antipsychotic is unlikely to be effective. If a woman continues taking lithium during pregnancy:- check plasma lithium levels every 4 weeks, then weekly from the 36th week. Adjust the dose to keep plasma lithium levels in the woman’s therapeutic range- ensure the woman maintains an adequate fluid balance- ensure the woman gives birth in the hospital- ensure monitoring by the obstetric team when labour starts, including checking plasma lithium levels and fluid balance because of the risk of dehydration and lithium toxicity- stop lithium during labour and check plasma lithium levels 12 hours after her last dose.

Eight percentage of infantile haemangiomas are focal and solitary. Sixty percent of cutaneous haemangiomas occur on the head and neck, 25% on the trunk, and 15% on the extremities. Haemangiomas also can occur in extracutaneous sites, including the liver, gastrointestinal tract, larynx, CNS, pancreas, gall bladder, thymus, spleen, lymph nodes, lung, urinary bladder, and adrenal glands.Guidelines on the management of infantile haemangioma were released in December 2018 by the American Academy of Paediatrics stating that:Imaging is not necessary unless the diagnosis is uncertain, there are five or more cutaneous infantile haemangiomas present, or there is suspicion of anatomic abnormalities.

Tuner’s syndrome is not associated with arachnodactyly.Arachnodactyly is seen in the following conditions:- Marfan syndrome- Homocystinuria- Ehlers-Danlos syndrome- Congenital contractural arachnodactylyOther rare syndromes include:- Loeys-Dietz syndrome- Antley-Bixler syndrome- Marden-Walker syndrome- Lujan-Frinz syndrome- Haim-Munk syndrome- Marden-Walker syndrome- Spondylocostal dysostosis

Measles and chickenpox are spread by droplets. Thus, patients should be isolated. Rheumatic fever and post-streptococcal glomerulonephritis are immune mediated diseases that don’t require isolation. Herpetic gingivostomatitis spreads by direct transmission of infected secretions to the stratified squamous epithelium. HSP is not an infectious disease.

Bone marrow failure syndromes are characterized by the bone marrow’s inability to produce cells of different lineage. They can be classified as those affecting one or two cell lineages or those affecting all three of them. Fanconi syndrome, along with dyskeratosis congenita, is one of the inherited bone marrow failure syndromes that causes pancytopenia. Other inherited disorders affecting hematopoietic lineage include Diamond-Blackfan anaemia, Schwachman-Diamond syndrome, congenital amegakaryocytic thrombocytopenia (CAMT) and Thrombocytopenia absent radii (TAR) syndrome. Acquired causes of bone marrow failure that lead to pancytopenia include aplastic anaemia, drugs, nutritional deficiencies, and viral infections. Kostmann syndrome is an autosomal recessive form of severe neutropenia, most likely due to excessive neutrophil apoptosis.

The most probable diagnosis in this patient is Noonan syndrome.Noonan syndrome is an autosomal dominant condition characterised by short stature, heart defects (mainly pulmonary stenosis) and learning difficulties. An affected foetus can present with a significant increase in the nuchal thickness or a cystic hygroma of the neck. The condition is variable, and an affected parent is often only diagnosed after the diagnosis in the child.

Psoriasis is an autoimmune dermatological condition that causes cells of the epidermal layer to rapidly develop, leading to itchy scaly plaques. Phototherapy with UV radiation has emerged as a new treatment for difficult to treat psoriasis. The therapy works by inducing epidermal cell apoptosis by DNA damage through the formation of pyrimidine dimerization, disrupting the cell cycle. This slows the rapid proliferation of cells.

The spinal cord ends at L3 in the new-bornmigrates cephalad during childhood to end at L1 – L2 and reaches adult size by the age of 10.

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.

History of recurrent infections and failure to thrive (probably due to pancreatic enzyme insufficiency) is highly suggestive of cystic fibrosis. Pseudomonas has been identified as an important respiratory pathogen in patients with cystic fibrosis.

Many factors are related with the stimulation of bone formation and growth, the pubertal growth spurt, epiphyseal senescence, and fusion, including nutritional, cellular, paracrine, and endocrine factors. An important cellular factor in these processes is the differentiation and aging of chondrocytes in the growth plate. Important paracrine factors include the many molecular pathways involved in chondrocyte differentiation, vascularization, and ossification. Oestrogen and the GH-IGF-I axis are important endocrine factors.

Melanoma, a highly malignant tumour arising from melanocytes, is the most common life-threatening dermatological disease. Risk factors include UV radiation exposure, particularly in light-skinned individuals that are easily sunburned, increasing age, family history, and immunosuppression. Lesions that are suspicious for melanoma should be excised with complete margins. Radical excision is not routinely undertaken for diagnostic purposes and therefore if subsequent histopathological assessment determines that the lesion is a melanoma a re-excision of margins may be required.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 – 3cm

Burkitt lymphoma is associated with the c-myc gene translocation, usually t(8|14). Burkitt lymphoma is a rare high-grade non-Hodgkin lymphoma endemic to west Africa and the mosquito belt. It has a close association with the contraction of Epstein-Barr virus (EBV). Burkitt lymphoma often presents with symmetrical painless lymphadenopathy, systemic B symptoms (fever, sweats, and weight loss), central nervous system involvement, and bone marrow infiltration. Classically in the textbooks, the patient also develops a large jaw tumour.Other aforementioned options are ruled out because:1. t(9|22)—Chronic myeloid leukaemia2. t(15|17)—Acute promyelocytic leukaemia3. t(14|18)—Follicular Lymphoma4. t(11|14)—Mantle Cell Lymphoma

Incontinentia pigmenti is a genetic condition that affects females more than males. It usually manifests in the skin but can affect other parts of the body as well. It presents with a blistering rash that may evolve into wart-like growths. Hyperpigmentation and hair loss are also present, as well as eye and teeth abnormalities. Clinically there are three phases: 1- the bullous phase – crops of vesicles appear in the first 2 weeks of life|2- the papular phase – warty papules that flatten out over the skin| and 3- the hyperpigmented phase – pigmentary changes in the form of whorls and streaks that are hypo- and hyperpigmented in nature.