The main problem with infants having gastroenteritis is dehydration. So they should be admitted to the hospital for IV fluids if they are not tolerating oral fluids.

Dandy-Walker syndrome is characterised by symptoms of brain maldevelopment that are seen in this patient. A large cranium indicates hydrocephalus, and the hypotonia indicates poor limb development.

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.

Congenital hypertrophy of the retinal pigment epithelium is one of FAP’s extra-intestinal manifestations. It appears in early childhood and affects an estimated 90% of those with FAP.

Infective endocarditis (IE) is caused by a bacterial, or fungal infection which damages the heart’s endothelium and can thus lead to changes in heart function, valve incompetencies, possible cardiac failure, as well other associated skin and organ changes. Organisms common in IE include Staphylococcus aureus and Streptococcus viridians. The HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella species) are common in neonates. The Duke criteria uses 2 major, or 1 major and 3 minor criteria, or 5 minor criteria to diagnose infective endocarditis. Major criteria include:- a positive blood culture and evidence of endocardial involvement. Minor criteria include: – evidence of predisposition (a heart condition of injection drug use)- a fever- vascular phenomena such as Janeway lesions- immunologic phenomena such as Osler’s nodes and Roth’s spots| and- microbiological or serological evidence of active infection.

Cyanotic congenital heart disease (CCHD) is a common cause of neonatal morbidity and mortality. They can be classified as CCHD due to:- Right-to-left shunt, associated with the decreased pulmonary flow, e.g., tetralogy of Fallot (TOF), pulmonary atresia, right-sided hypoplastic heart,- Right-to-left shunt, associated with the decreased aortic flow, e.g., left-sided hypoplastic heart, interrupted arch, severe coarctation| – Bidirectional shunt, e.g., TGA, DORV, TA, etc. Eisenmenger syndrome is not a neonatal CCHD| rather it develops later in young adulthood secondary to various CHD.

The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.

This patient has pulmonary renal syndrome which is most commonly due to an ANCA positive vasculitis. The history of recurrent epistaxis makes Wegener’s granulomatosis the most probable diagnosis. Wegener’s granulomatosis, microscopic polyangiitis, and idiopathic pauci-immune necrotizing crescentic glomerulonephritis (NCGN) are strongly associated with antineutrophil cytoplasmic autoantibodies (ANCAs) directed against either proteinase 3 (anti-PR3) or myeloperoxidase (anti-MPO).

According to the Gell and Coombs classification of hypersensitivity reactions, the scenario provided is a type 4 (delayed) reaction.These reactions are mediated by T lymphocytes and cause contact dermatitis. Nickel, commonly found in cheap jewellery, is a common cause of contact dermatitis.Note:There are two main types of contact dermatitis:- Irritant contact dermatitis: It is a common, non-allergic reaction due to weak acids or alkalis (e.g. detergents). These are often seen on the hands. They present typically with erythema, and rarely, crusting and vesicles.- Allergic contact dermatitis: These are type IV hypersensitivity reactions and are often seen on the head following hair dyes.They typically present as acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself. Treatment is usually with a potent topical steroid.Other options:- Allergic rhinitis is an example of a type 1 (immediate) reaction. It is an IgE mediated. It is a hypersensitivity to a previously innocuous substance.- Type 2 reactions are mediated by IgG and IgM, which binds to a cell, causing cell death. Goodpasture syndrome is an example of a type 2 hypersensitivity reaction.- Immune complexes mediate type 3 reactions. Rheumatoid arthritis is an example of a type 3 hypersensitivity reaction.

Among the given options, the inability to grip a sheet of paper between his fingers when the hand is placed flat on the table is the feature of ulnar nerve injury. Rationale:The ulnar nerve (usually) supplies sensation to the skin of the fifth and the ulnar side of the fourth finger, front and back. Following the injury of the nerve, the following functions are impaired:- There is a sympathetic interruption, with the absence of sweating in the affected area. – The thenar muscles are supplied by the median nerve and are therefore spared. – The ulnar nerve also supplies the muscles of the hypothenar eminence. – Although the ring and little fingers are held in the clawed position when the nerve is injured at the wrist, a high lesion paralyses the long flexors to these two fingers and results in the loss of this sign. The test for paralysis of the palmar interossei, supplied by the ulnar nerve, is the inability to adduct the fingers and thus to be unable to grip a sheet of paper between them.