Compared to parametric tests, non parametric tests are seen to be less powerful as they often contend with fewer assumptions, and may use less information from the data. Sample sizes can be smaller. The samples do not have to follow a normal distribution as in parametric tests, and data may be ordinal, ranked or contain outliers that cannot be removed. Therefore nonparametric tests are well suited for these instances and do not need to be used as a last resort. They are not any more complex than parametric tests.

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.

People who are at risk for severe illness and complications from measles, such as infants younger than 12 months of age, pregnant women without evidence of measles immunity, and people with severely compromised immune systems, should receive immunoglobulin. Intramuscular immunoglobulin should be given to all infants younger than 12 months of age who have been exposed to measles. For infants aged 6 through 11 months, MMR vaccine can be given in place of IG, if administered within 72 hours of exposure.

Time and EventWeek 1: ImplantationWeek 2: Formation of bilaminar diskWeek 3: Formation of primitive streakFormation of notochordGastrulationWeek 4: Limb buds begin to formNeural tube closesHeart begins to beatWeek 10: Genitals are differentiated

Precocious puberty is the development of secondary sexual characteristics before the age of 8 in females, and 9 in males. The first sign of early puberty in females is breast enlargement, followed by the appearance of pubic and axillary hair, and finally menarche, 2-3 years after the onset of thelarche. Precocious puberty is caused by the premature activation of the hypothalamic-pituitary-gonadal axis where FSH and LH levels are raised. Less common is the gonadotrophin independent form, which is due to excess sex hormones, but low FSH and LH levels.

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.

The heart is the first organ to form and become functional, emphasizing the importance of transport of material to and from the developing infant. It originates about day 18 or 19 from the mesoderm and begins beating and pumping blood about day 21 or 22. It forms from the cardiogenic region near the head and is visible as a prominent heart bulge on the surface of the embryo. Originally, it consists of a pair of strands called cardiogenic cords that quickly form a hollow lumen and are referred to as endocardial tubes. These then fuse into a single heart tube and differentiate into the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and sinus venosus, starting about day 22. The primitive heart begins to form an S shape within the pericardium between days 23 and 28. The internal septa begin to form about day 28, separating the heart into the atria and ventricles, although the foramen ovale persists until shortly after birth. Between weeks five and eight, the atrioventricular valves form. The semilunar valves form between weeks five and nine.

Normal QT interval in a 6 months old baby is < 0.44 seconds. A duration exceeding this value is referred to as QT interval prolongation, which is associated with some important congenital syndromes that include Brugada syndrome which is characterized by vasovagal syncope and sudden cardiac death, Jervell and Lange-Nielsen syndrome which is associated with congenital deafness, Andersen syndrome which is marked by bone deformities, and Timothy syndrome with associated heart disease and immunodeficiency. Romano-Ward syndrome is the commonest cause of congenital QT prolongation with no associated extra-cardiac manifestations. Lown-Ganong-Levine syndrome is characterized by a shortened PR interval and a normal QRS duration.

Nissl body is a neuron-specific cellular structure. It is composed of rough endoplasmic reticulum and fine granules. The rough endoplasmic reticulum contains free ribosomes, and are the hub of protein synthesis. When these substances are exposed to a cresyl violet solution, they show selective-staining by turning purple-blue. In pathologic processes, they may undergo chromatolysis.

Based on the clinical scenario, the most probable diagnosis for this patient is maxillary sinusitis.The maxillary sinus drains from its superior aspect, leaving it prone to infections. It is the most commonly affected sinus in sinusitis.Common symptoms of maxillary sinusitis include postnasal discharge, pain, headache and toothache.Radiological imaging may show a fluid level in the antrum.Common organisms causing maxillary sinusitis include Haemophilus influenzae or Streptococcus pneumoniae.Treatment with antral lavage may facilitate diagnosis and relieve symptoms. Antimicrobial therapy has to be continued for long periods. Antrostomy may be needed.Other options:- Frontal sinusitis more commonly causes intracranial complications, but it is still less frequent than maxillary sinusitis.- The petrosal sinus is not a cavity within bone| rather, it is a venous structure located beneath the brain.- Frontoethmoidal sinusitis: It usually presents with frontal headache, nasal obstruction and altered sense of smell. Inflammation may progress to involve periorbital tissues. Ocular symptoms may occur, and secondary CNS involvement brought about by infection entering via emissary veins. CT scanning is the imaging modality of choice. Early cases may be managed with antibiotics. More severe cases usually require surgical drainage.

Hyposplenism is associated with thrombocytosis. Other features of hyposplenism are: – Howell-Jolly bodies and acanthocytosis, occurring secondary to haemolysis.- Pappenheimer bodies: These are granular deposits of iron found within the RBCs.- Lymphocytosis and monocytosis.Causes for hyposplenism include:- Congenital asplenia- Iatrogenic splenectomy: Following trauma or treatment for ITP, thalassemia or spherocytosis).- Autosplenectomy: Secondary to sickle cell anaemia, coeliac disease, dermatitis herpetiformis, essential thrombocythemia or splenic arterial thrombosis).

Craniopharyngiomas (also known as Rathke pouch tumours, adamantinomas or hypophyseal duct tumours) affect children mainly between the age of 5 and 10 years. It constitutes 9% of brain tumours affecting the paediatric population. These are slow-growing tumours which can also be cystic, and arise from the pituitary stalk, specifically the nests of epithelium derived from Rathke’s pouch. Histologically, this tumour shows nests of squamous epithelium which is lined on the outside by radially arranged cells. Calcium deposition is often seen with a papillary type of architecture.
ACTH-secreting pituitary adenomas are rare and mostly microadenomas. Paediatric astrocytoma’s usually occur in the posterior fossa. Although null cell adenomas can cause mass effect and give rise to the described symptoms, they are not suprasellar. Prolactinomas can also show symptoms of headache and disturbances in the visual field, however they are known to be small and slow-growing.

A height that is above the 97th percentile for age and sex is described as a tall stature. The most common cause of tall stature is constitutional or familial, followed by nutritional causes. Hormonal causes of tall stature include hyperthyroidism, growth hormone excess, and precocious puberty. Some important chromosomal and syndromic causes of tall stature are Klinefelter’s syndrome, homocystinuria, Marfan’s syndrome, Sotos syndrome, Beckwith-Weidman syndrome, and Weaver syndrome. Laurence-Moon syndrome is an autosomal recessive disorder characterized by short stature, retinitis pigmentosa, and spastic paraplegia.

Among the given options a 2-year-old child with normal developmental milestones will be able to pull and push large wheeled toys and squat to play with toys on the floor.Other options:- Bouncing and catching a ball is learnt by the age of 5.- The ability to pedal a tricycle should be attained by 3 years of age, not 2.- A child can walk on tip-toe by 2.5 and run on tip-toe by (option D) 3 years of age, not 2.- The ability to momentarily maintain balance using one leg (option E) should be attained by 3 years.

Tooth extraction or any surgical procedure may introduce bacteria into the blood stream. The most commonly involved organisms include Staphylococcus aureus and Streptococcus viridans. Once in the blood, these organisms have a very high tendency of attaching to the walls of the heart and causing inflammation known as endocarditis.

The vignette describes an infant with a sustained post-delivery brachial plexus injury that does not improve with time. MRI is the most appropriate intervention to assess the injury and evaluate the treatment options.

Among the given options, psoriasis is not associated with hypertrichosis.The causes of hypertrichosis include:- Drugs: minoxidil, ciclosporin, and diazoxide.- Congenital hypertrichosis lanuginosa and congenital hypertrichosis terminalis.- Porphyria cutanea tarda- Anorexia nervosa

From the given clinical scenario, the peroxisomal disorder in question is Refsum’s disease.It is characterised by anosmia, early-onset retinitis pigmentosa (night blindness), chronic ataxia, variable neuropathy, deafness and ichthyosis. It is an inherited disorder of fatty acid oxidation with phytanic acid accumulation in the blood and tissues. This leads to the motor and sensory neuropathy. Other options:- Loss of sensation in extremities, dysarthria and diabetes is suggestive of Friedrich’s Ataxia. It is the most common autosomal recessive cause of ataxia. Associated features include dysarthria, scoliosis, diabetes and hypertrophic cardiomyopathy. – Numbness of the limbs, seizures and developmental delay suggests mitochondrial cytopathy such as NARP (Neuropathy, Ataxia and Retinitis Pigmentosa). Learning difficulties, developmental delays and convulsions are not uncommon, as with many mitochondrial disorders. – Rapid, chaotic eye movements, behaviour change and irritability, suggest opsoclonus-myoclonus syndrome. It is thought to be a Para infectious or paraneoplastic condition (secondary to neuroblastoma) linked to an abnormal immune response. Children present unwell with altered behaviour, irritability, ataxia, random chaotic eye movements and later myoclonus. – Sweet-smelling urine, lethargy and seizures suggest Maple Syrup Urine Disease (MSUD). It is an autosomal recessive organic acidaemia. There is a distinct sweet odour to the urine of affected individuals, particularly at times of acute illness. Without treatment, MSUD can lead to seizures, brain damage, coma and death. The most common and classic form affects babies shortly after birth, but variant forms may not be evident until later childhood.

The injury described in question leads to an abnormal communication between the orbit and the ipsilateral maxillary sinus – this is termed as a blow-out fracture of the orbit.The maxillary sinuses are found in the maxillary bone, inferior to the orbit. They are the largest of the paranasal air sinuses. The maxillary bone forms the floor of the orbit. This layer of bone separates the orbit from the maxillary sinus. As such, fractures of the floor of the orbit can be associated with herniation of the orbital contents into the maxillary sinus. Other options:- The ethmoidal air cells are a collection of smaller air cells in the ethmoid bone. They lie lateral to the anterior superior nasal cavity. They are separated from the orbit by a very thin plate of ethmoid bone called the lamina papyracea, which is found on the medial wall of the orbit. The thin nature of this bone means it is commonly fractured in orbital trauma. However, this is the incorrect answer to the above question as a communication between the ethmoidal air cells, and the orbit is associated with fractures of the medial wall of the orbit, not the floor. – The frontal sinuses are found in the frontal bones, above the orbits on each side of the head. A large portion of the roof of the orbit is composed of the frontal bone and separates the orbit from the frontal sinus. Fractures of the roof of the orbit can be associated with communication between the frontal sinus and orbit. The frontal bones are strong, and so fracture is associated with high-impact anterior trauma, such as a road traffic accident. – The sphenoid sinuses are found in the posterior portion of the roof of the nasal cavity. The pituitary gland lies nestled within the hypophyseal fossa, with only a thin wall of bone separating it from the sphenoid sinus below. As such, neurosurgeons can gain access to the pituitary gland via the sphenoid sinus, in a procedure called transsphenoidal hypophysectomy. – The nasal cavity extends from the nares to the nasopharynx. It is found more medial and inferior than the orbits. It does not lie adjacent to the orbit at any point and so is unlikely to be involved in an orbital fracture.

Lichen sclerosus is a common chronic skin disorder that most often affects genital and perianal areas. LS typically presents with vulval itching and clinical findings of pallor, epidermal atrophy (cigarette paper wrinkling), purpura, and/or erosions.Lichen sclerosus (LS) and lichen planus (LP) are both immunologically mediated diseases with a preference for the genitalia. The main difference between the two conditions is that LP has a propensity to involve the mucous membranes including the mouth and vagina which are rarely affected in LS.

Polycythaemia is a condition in which there is an increased red cell mass and increasing blood viscosity, which decreases its ability to flow. It is not associated with food allergies, but is fundamentally caused by either an overproduction of red blood cells, or a reduction in the volume of plasma. Abdominal pain, constipation, loose and frequent stools, and pallor are all non IGE mediated symptoms of food allergy according to NICE guidelines in the UK.

Based on the findings presented, the sign elicited is Rovsing’s sign.Rovsing’s sign:It is a sign suggestive of appendicitis. A positive sign is determined when palpation in the left lower quadrant of a patient’s abdomen causes pain in the right lower quadrant.Other options:- Murphy’s sign is positive in gallbladder inflammation. With the upper border of the examiner’s hand in the right upper quadrant of the abdomen under the rib cage, the patient is asked to inhale. Inhalation causes the gallbladder to descend, which catches on the fingers, causing pain.- Cullen’s sign is suggestive of ectopic pregnancy or acute pancreatitis and describes the bruising around the umbilicus.- Tinel’s sign is positive in those with carpal tunnel syndrome. The examiner’s fingers tap the median nerve over the flexor retinaculum, which causes paraesthesia over the distribution of the median nerve.- Battles’ sign describes bruising behind the ear, suggesting a basal skull fracture of the posterior cranial fossa.

HUS syndrome occurs mostly in children after some days of bloody diarrhoea. Damaged red blood cells also damage the kidney filtering unit and lead to sudden renal failure.

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.

3-year-old milestones:Social and Emotional:- Copies adults and friends – Shows affection for friends without prompting – Takes turns in games – Shows concern for crying friend – Understands the idea of “mine” and “his” or “hers” – Shows a wide range of emotions – Separates easily from mom and dad – May get upset with major changes in routine- Dresses and undresses self Language/Communication- Follows instructions with 2 or 3 steps – Can name most familiar things – Understands words like “in,” “on,” and “under” – Says first name, age, and sex- Names a friend – Says words like “I,” “me,” “we,” and “you” and some plurals (cars, dogs, cats) – Talks well enough for strangers to understand most of the time – Carries on a conversation using 2 to 3 sentencesCognitive (learning, thinking, problem-solving)- Can work toys with buttons, levers, and moving parts – Plays make-believe with dolls, animals, and people – Does puzzles with 3 or 4 pieces – Understands what “two” means – Copies a circle with a pencil or crayon – Turns book pages one at a time – Builds towers of more than 6 blocks – Screws and unscrews jar lids or turns the door handleMovement/Physical Development- Climbs well – Runs easily – Pedals a tricycle (3-wheel bike) – Walks up and downstairs, one foot on each stepDoing up buttons is a skill more usually seen in 5-year-olds.

Acoustic neuroma/vestibular schwannoma is a benign slow-growing tumour. The clinical picture of the child suggests neurofibromatosis type 1 (NF1), with cafe-au-lait spots and axillary and inguinal freckling.

The commonest time for bacterial meningitis is in the 1st month of life and group B Streptococcus is the commonest organism. The anterior fontanelle is full, but does not bulge with normal flexion. Neurological manifestations include seizures, irritability, poor tone, lethargy and tremors, however no findings of sensorineural deafness have been noted. One of the risk factors for introduction of meningeal infection is Meningomyelocele.

With children nosebleeds often occur after nose picking and are benign in nature. For active bleeding, pressing of soft parts of the nose is required to stop the bleeding before doing anything else.

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.

Alopecia is a scalp condition characterized by either overall baldness or patches of hair loss over the head. It can be broadly classified as scarring alopecia and non-scarring alopecia. Non-scarring is the most common type and is seen in various conditions like nutritional deficiencies, alopecia areata, hypothyroidism, tinea capitis, and SLE. Scarring alopecia is commonly seen in cases of discoid lupus erythematosus, which is a common cause of widespread inflammatory and scarring lesions all over the body and scalp.