Pale stools suggest obstructive jaundice. Initially, the symptoms of biliary atresia are indistinguishable from those of neonatal jaundice, a usually harmless condition commonly seen in infants. However, infants with biliary atresia develop progressive conjugated jaundice, pale white stools and dark urine.

The type of significance test used depends on whether the data is parametric (can be measured, usually normally distributed) or non-parametric.
Parametric tests:
Student’s t-test – paired or unpaired*
Pearson’s product-moment coefficient – correlation

Non-parametric tests:
Mann-Whitney U test – unpaired data
Wilcoxon signed-rank test – compares two sets of observations on a single sample
chi-squared test – used to compare proportions or percentages
Spearman, Kendall rank – correlation.

The outcome measured is not normally distributed, i.e. it is non-parametric. This excludes the Student’s t-tests. We are not comparing percentages/proportions so the chi-squared test is excluded. The Mann–Whitney U test is a nonparametric test of the null hypothesis that it is equally likely that a randomly selected value from one sample will be less than or greater than a randomly selected value from a second sample.
This test can be used to investigate whether two independent samples were selected from populations having the same distribution.

The CSF picture in bacterial meningitis has the following characteristics: several polymorphs, cells, protein that is maximum 5g/l, a few lymphocytes and glucose that accounts for the two thirds of the blood level.

Intussusception causes abdominal pain leading to painful lower GI bleeding. Intussusception is a condition in which part of the intestine folds into the section next to it. It most commonly involves the small bowel and rarely the large bowel. Intussusception doesn’t usually require surgical correction. 80% of cases can be both confirmed and reduced using barium, water-soluble or air-contrast enema.However, up to 10% of cases can experience recurrence within 24 hours after reduction, warranting close monitoring during this period.Most children have self-limiting and minor bleeds. However, children with massive bleeds will need emergency care and stabilisation.The various causes of lower GI bleeding in neonates include:- Anal fissures- Milk protein or soy allergy- Intussusception- Volvulus- Coagulopathies including haemorrhagic disease of the new-born- Arteriovenous malformations- Necrotising enterocolitis- Hirschsprung enterocolitis- Meckel’s diverticulitis- Drugs (NSAIDs, heparin, indomethacin used for patent duct closure, dexamethasone)The various causes of lower GI bleeding in children aged between 1 month to 2 years include:- Infection- Anal fissures- Intussusception- Malrotation with volvulus- Milk protein or soy allergy- Polyp- Meckel’s diverticulum- Duplication cyst- Foreign body- AV malformation- Colitis of immune deficiency- Tumour- HaematomaThe causes of lower GI bleeding in children older than 2 years include:- Polyp- Inflammatory bowel disease (IBD)- Infectious diarrhoea (caused by Escherichia coli and Shigella)- Intussusception- Haemangiomas- Arteriovenous malformations- Vasculitis- Tumour

Ataxic gait is not a direct association of Down’s syndrome. All other given responses are associated with Down’s syndrome.

The most probable diagnosis for this patient would be a duplex kidney with an ectopic ureter inserting below the bladder neck. Rationale: The Weigert-Myer law states that the upper moiety ureter inserts inferior and medial to the lower moiety ureter. Other options:- Horseshoe kidney would display as a single pelvic kidney on an ultrasound scan.- Ureterocele would be a cystic lesion within the bladder or may prolapse at birth. – Continence should not be affected by polycystic kidney disease. – The overactive bladder would cause frequency and urgency, neither of which is mentioned in the history.

Among the options provided, an 8-week-old full-term infant with normal developmental milestones will smile in response to appropriate stimuli.Rationale:Smiles in response to appropriate stimuli are seen from around 6 weeks of age. A social smile, where the infant has an awareness that a smile attracts attention, is not observed until around 3 months of age.Other options:- At 6 weeks an infant is able to follow objects in the horizontal plane through 90 deg| fixing and following an object through 180 deg in the horizontal plane is a milestone achieved at 3 months, as is pushing up onto forearms. – Pushing up onto hands occurs by around 5 months.- Infants of 3 months should startle to a 60 dB sound.

Adrenal insufficiency is a serious medical condition that leads to inadequate secretion of corticosteroids. There are three main types of adrenal insufficiency: primary, secondary, and tertiary, based on the location of the abnormality. Primary adrenal insufficiency is caused by any pathology located inside the adrenal glands. The most common cause of primary adrenal insufficiency is Addison’s disease, which is an autoimmune condition. Adrenoleukodystrophy is an X-linked neurodegenerative disease that also causes primary adrenal insufficiency. Secondary adrenal insufficiency is caused by any pathological impairment of the pituitary gland or the hypothalamus. The important causes of secondary adrenal insufficiency include iatrogenic (steroid use), pituitary tumours like craniopharyngioma, and conditions leading to panhypopituitarism like Sheehan’s syndrome. Tertiary adrenal insufficiency is caused by the deficiency of the corticotropin-releasing hormone. Hypoparathyroidism does not cause adrenal insufficiency.

Congenital LQTS arises from mutations in genes that code for ion channels within myocytes.These mutations all cause ventricular action potentials to be prolonged, resulting in a lengthened QT interval on ECG. The congenital long-QT syndrome (LQTS) is a life-threatening cardiac arrhythmia syndrome that represents a leading cause of sudden death in the young. LQTS is typically characterized by a prolongation of the QT interval on the ECG and by the occurrence of syncope or cardiac arrest, mainly precipitated by emotional or physical stress.LQTS type 1Most common type of congenital LQTSDefect: loss of function mutation on the KCNQ1 gene located on chromosome 11p → defective slow delayed rectifier voltage-gated potassium channelSubtypesJervell and Lange-Nielsen syndrome Associated with congenital deafnessAutosomal recessiveAssociated with ventricular tachyarrhythmiasRomano-Ward syndrome No associated deafnessAutosomal dominantAssociated with ventricular tachyarrhythmias

A complete course of DPT should be given.