The differentiation between type 1 and type 2 epithelia in the developing lung buds is evident from 16-24 weeks of gestation.Development of the respiratory tract has five stages:- Embryonic (at 4 – 5 weeks of gestation):Formation of lung buds, trachea and mainstem bronchi occur. These structures are formed from a ventral outpouching of foregut pharynx. At this stage, the beginnings of the five lung lobes are present.- Pseudoglandular (at 5 – 16 weeks of gestation):Formation of terminal bronchioles, cartilage and smooth muscles occur in this stage. – Canalicular (at 16-24 weeks gestation): Differentiation of type I and II epithelial cells can be done in this stage. There is also an increase in the size of proximal airways).- Saccular (at 24 – 40 weeks of gestation): Terminal saccule formation occurs. Production of surfactant takes place at this stage with an increase in the number of goblet cellsUp to half the adult number of alveoli are in place by this stage.- Alveolar (occurs between 32 weeks of gestation till the post-natal age 8): Formation of alveoli and septation occurs with the expansion of air spaces.

Undescended testis (UDT) is a common abnormality, affecting about 1/20 males at birth. Half of these have delayed testicular descent, with the testis in the scrotum by 10-12 weeks after term. Beyond this spontaneous descent is rare. Current treatment recommendations are that UDT beyond 3 months need surgery between 6-12 months of age. Some children have scrotal testes in infancy but develop UDT later in childhood because the spermatic cord does not elongate with age, leaving the testis behind as the scrotum moves further from the groin. The maldescended testis suffers heat stress when not at the lower scrotal temperature (33 degrees Celsius), interfering with testicular physiology and development of germ cells into spermatogonia. Recent evidence suggests orchidopexy between 6-12 months improves germ cell development, with early reports of improved fertility, but no evidence yet for changes in malignancy prognosis.Hypospadias is also a common abnormality in new-born males, affecting about 1/150 boys. Androgens control masculinization of the genital tubercle into penis between 8-12 weeks’ gestation, with tabularization of the urethra from the perineum to the tip of the glans. If this process is disrupted hypospadias occurs, with a variable proximal urethral meatus, failed ventral preputial development producing a dorsal hood, and discrepancy in the ventral versus dorsal penile length, causing a ventral bend in the penis, known as chordee. Surgery to correct hypospadias is recommended between 6-18 months.

The rational part of a teen’s brain isn’t fully developed until the age of 25 or so.In fact, recent research has found that adult and teen brains work differently. Adults think with the prefrontal cortex, the brain’s rational part. This is the part of the brain that responds to situations with good judgment and an awareness of long-term consequences. Teens process information with the amygdala. This is the emotional part.

Human breast milk composition is best suited to meet all the growth and development requirements of a baby. It contains numerous biochemicals ranging from macronutrients, micronutrients, minerals, immunoglobulins, inflammatory markers, and growth factors. The major bioactive factors found in human breast milk are: immunoglobulins (IgA, IgG, and IgM), cells (macrophages and stem cells), growth factors (epidermal growth factor, tumour necrosis factor-alpha, transforming growth factor-beta, and vascular endothelial growth factor), cytokines, chemokines, hormones, metabolic hormones, glycans, and mucins.

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.

The accuracy of the test for calcium levels in the blood is affected by the blood level of albumin. If albumin levels are low, the calcium level can also appear low.This is termed as pseudohypocalcemia.Hypocalcaemia usually presents with muscle spams. These can include spasms of voluntary muscle but also smooth muscle such as in the airways (causing bronchospasm) and in the heart (causing angina).

In this case there is evidence of disseminated intravascular coagulation (DIC) caused by severe birth asphyxia. The baby was born weighing 4,9 kg which is a large size for a new-born and thus a difficult delivery with potential birth asphyxia.

Many of the symptoms favour an epilepsy diagnosis: uncontrollable jerking of the limbs and a loss of consciousness. A 24-hour EEG is used to diagnose epilepsy.

Bitemporal hemianopia is a characteristic finding seen in patients with optic chiasm lesion.The pituitary gland is situated within the pituitary fossa. Just above the pituitary fossa is the optic chiasm and so any expanding masses from the pituitary gland commonly press on it, causing bitemporal hemianopia.Other options:- Compression of the optic nerve would not cause more severe, generalised visual loss. Also, the optic nerve is not anatomically related to the pituitary gland and so is unlikely to be directly compressed in the presence of a pituitary tumour.- The optic tract is again not closely anatomically related with the pituitary gland and so is unlikely to be directly compressed in the presence of a pituitary tumour. Also, damage to the optic tract on one side would cause homonymous hemianopia.- The lateral geniculate nucleus is a centre of cells in the thalamus and is unlikely to be compressed by a pituitary tumour. Its function is to convey sensory information from the optic tract to more central parts of the visual pathway.- The Edinger-Westphal nucleus is located at the level of the superior colliculus in the midbrain and so may not be compressed by an enlarging pituitary tumour.Other visual defects:- Left homonymous hemianopia: It is the visual field defect to the left, due to the lesion of the right optic tract.- Homonymous quadrantanopias are seen in parietal (inferior homonymous quadrantopia) and temporal lobe lesions (superior homonymous quadrantopia). Mnemonic: PITS (Parietal-Inferior, Temporal-Superior)A congruous defect means complete or symmetrical visual field loss, and conversely, an incongruous defect is incomplete or asymmetric.Incongruous defects suggest an optic tract lesion, while congruous defects suggest optic radiation or occipital cortex lesion.

CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles. CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen (also called the foramen of Monro). The third ventricle and fourth ventricle are connected to each other by the cerebral aqueduct (also called the Aqueduct of Sylvius). CSF then flows into the subarachnoid space through the foramina of Luschka (there are two of these) and the foramen of Magendie (only one of these).Absorption of the CSF into the blood stream takes place in the superior sagittal sinus through structures called arachnoid villi . When the CSF pressure is greater than the venous pressure, CSF will flow into the blood stream.

Minimal change nephrotic syndrome leads to the loss of anti-thrombin III which protects the body from forming venous emboli. It may be triggered by virus, immunisations, medication, non-Hodgkin lymphoma, or leukaemiaCharacterised by oedema, proteinuria, hypoalbuminemia, and hypercholesterolemia.

Vaccines should not be given to a feverish child.

A 10 year old child, with a history of URTI and haematuria, presents a picture consistent with a diagnosis of IgA nephropathy. This condition can present with proteinuria and generalized swelling. However, an important differentiating point from rapidly progressive GN is the duration. IgA nephropathy is usually <10 days (commonly 4-5 day history of infection).

The baby has duodenal atresia.Presenting symptoms and signs are results of high intestinal obstruction. Duodenal atresia is typically characterized by the onset of vomiting within hours of birth. While vomitus is most often bilious, it may be nonbilious because 15% of defects occur proximal to the ampulla of Vater. Occasionally, infants with duodenal stenosis escape detection of an abnormality and proceed into childhood or, rarely, into adulthood before a partial obstruction is noted. Nevertheless, one should assume any child with bilious vomiting has a proximal GI obstruction until proven otherwise, and further workup should be begun expeditiously.congenital duodenal atresia is one of the more common intestinal anomalies treated by paediatric surgeons, occurring 1 in 2500-5000 live births. In 25-40% of cases, the anomaly is encountered in an infant with trisomy 21 (Down syndrome).

Answer: LaparoscopyThe diagnostic accuracy of laparoscopy for impalpable testis is well recognized. Approximately 20% of undescended testes are truly impalpable, and laparoscopy is actually regarded as the gold standard for their localization; none of the currently available imaging techniques (ultrasound, computerized tomography, or magnetic resonance imaging) has proven to be 100% reliable in predicting the presence or absence of a testis.In this respect, not only can laparoscopy be considered the most reliable tool to provide information on the location of the testis but also to confirm its absence.Undescended testes in boys is a very common congenital abnormality in which one or both testes does not reach the bottom of the scrotum prior to birth. The incidence of the condition is 3-5% among all boys at birth, and decreases to 0.8-1% after 6 months of age.Males with undescended testes have a lower sperm count, poorer quality sperm, and lower fertility rate, compared to males whose testicles descend normally; the rate of subfertility increases with bilateral involvement and increasing age at the time of orchidopexy.

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.

Skin conditions resulting from excessive epidermal proliferation or inflammation, leading to a production of excessive scales, are referred to as papulosquamous disorders. These disorders can be generalized and localized. Localized causes of scaly lesions include tinea corporis, tinea cruris, tinea pedis, seborrheic dermatitis, psoriasis, pityriasis Versicolor, pityriasis alba, DLE, ichthyosis including Netherton syndrome (a severe form of ichthyosis which is autosomal recessive), and pellagra. Generalized causes include guttate psoriasis and pityriasis rosacea. Hand, foot, and mouth disease is a contagious viral illness that causes blisters in the mouth and on the extremities.

Henoch-Schonlein purpura (HSP), also known as IgA vasculitis, is a disease of the skin, mucous membranes, and sometimes other organs that most commonly affects children. In the skin, the disease causes palpable purpura (small, raised areas of bleeding underneath the skin), often with joint pain and abdominal pain. It is an acute immunoglobulin A (IgA)-mediated disorder. The tetrad of purpura, arthritis, kidney inflammation, and abdominal pain is often observed.

Allergy: A history of a prior allergic-like reaction to contrast media is associated with an up to a 5-fold increase in the likelihood of experiencing a subsequent reaction. Also, any patient with a predilection to allergic reactions may predispose them to a reaction after the administration of contrast media. Given the increased risk of severe life-threatening anaphylaxis related to the administration of contrast media in the setting of the history of atopy, the risk versus benefits should be discussed before following through with the procedure. A premedication regimen may be used to reduce the risk of anaphylaxis.Asthma: A history of asthma may be indicative of a higher likelihood of developing a contrast reaction. Cardiac status: Attention must be turned to patients with significant cardiac disease (congestive heart failure, aortic stenosis, severe cardiomyopathy, and/or pulmonary hypertension), as higher volumes and osmolality of contrast material may result in an increased risk for a contrast reaction.Renal insufficiency: Contrast nephrotoxicity is defined as the rapid deterioration of renal function after the administration of contrast media when no other aetiology can be determined from the clinical records. The major predisposing risk factors include pre-existing renal insufficiency (defined as serum creatinine level >1.5 mg/dL) and diabetes. Other risk factors include dehydration, cardiovascular disease, the use of diuretics, advanced age (>70 years old), hypertension, and hyperuricemia. Obtaining multiple contrast-enhanced studies within 24 hours is also thought to increase the risk for contrast-induced nephrotoxicity. Miscellaneous: Relative contraindications to the use of high osmolality iodinated contrast media (HOCM) in patients with pheochromocytoma, sickle cell disease, and multiple myeloma have been reported. Although the administration of low osmolality or iso-osmotic contrast media may be beneficial in patients with pheochromocytoma and sickle cell disease, little evidence suggests that these agents mitigate the risks associated with multiple myeloma.

Vitamin E deficiency in premature infants has been described as being associated with low haemoglobin levels in the 2nd month of life, haemolytic anaemia associated with thrombocytosis. Recently, low vitamin E concentrations were suspected as being associated with sudden death in infancy.

Marfan syndrome is a disorder that affects the connective tissue found throughout the body, Marfan syndrome can affect many systems, often causing abnormalities in the heart, blood vessels, eyes, bones, and joints. The two primary features of Marfan syndrome are vision problems caused by a dislocated lens (ectopia lentis) in one or both eyes and aortic root disease, leading to aneurysmal dilatation, aortic regurgitation and dissection is the main cause of morbidity and mortality in Marfan syndrome.

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.

Chickenpox is a highly communicable viral disease caused by human (alpha) herpesvirus 3 (varicella-zoster virus, VZV). It is transmitted from person to person by direct contact (touching the rash), droplet or air born spread (coughing and sneezing).

The aetiology of macrocephaly is diverse.The most common cause is benign familial macrocephaly characterized by enlargement of the subarachnoid spaces and accounts for almost 50% of cases.Other causes are:- Enlargement of skull bones – Hyperostosis cranii – associated with disorders such as osteogenesis imperfecta, achondroplasia, and osteopetrosis- Secondary enlargement due to bone marrow expansion – as seen in thalassemia major- Increase in volume of cerebrospinal fluid- Hydrocephalus, Choroid plexus papilloma, Benign familial macrocephaly- Megalencephaly – Leukodystrophies – Canavan disease, Alexander disease, megalencephalic leukoencephalopathy with subcortical cysts- Lysosomal storage disorders – Tay-Sachs, mucopolysaccharidosis, gangliosidosis- Neurocutaneous disorders – Tuberous sclerosis, Sturge-weber syndrome, neurofibromatosis, Gorlin syndrome- Autism spectrum disorder- Other syndromes – Fragile X syndrome, Cowden syndrome, Sotos syndrome- Increased intracranial pressure (ICP)- CNS infections, Pseudotumor cerebriSubdural collections including hygromas- Mass lesions and an increase in the volume of bloodTumourIntraventricular haemorrhage, subdural hematoma, arteriovenous malformation

Congenital heart diseases such as complete atrioventricular septal defects are most likely to cause large left to right shunts leading to faltering growth due to chronic severe hypoxia, pulmonary oedema, and feeding problems. Isolated atrial septal defects or ventricular septal defects result in relatively smaller shunts. Pulmonary stenosis and bicuspid aortic valve do not cause chronic systemic hypoxia. People with these conditions are often asymptomatic and only show some symptoms with intense physical activity.

One-third of patients with Guillain-Barre syndrome suffer from diaphragm weakness which can lead to further respiratory complications if there is involvement of the tongue, palate, and neck muscles. Forced vital capacity (FVC) is the best way to monitor respiratory muscle function by assessing it repeatedly. Admission for ITU is suggested when FVC is below 20ml/kg and intubation recommended when FVC is 15ml/kg or below. FVC is used in any neurological disorders wherein the respiratory muscles are affected.

A transverse lie is a common malpresentation. It occurs when the fetal longitudinal axis is perpendicular to the long axis of the uterus. The location of the spine determines if the foetus is back up (the curvature of the spine is in the upper part of the uterus) or back down (the curvature of the spine is in the lower part of the uterus).Good antenatal care, ECV, and elective caesarean section are the mainstay of the management.Spontaneous delivery of a term foetus is impossible with a persistent transverse lie and, in general, the onset of labour is an indication for the lower segment caesarean section (LSCS) in a case of a transverse lie.

Common neurological symptoms of Wilson disease that may appear and progress with time include tremor, involuntary movements, difficulty swallowing (dysphagia), difficulty speaking and poor articulation (dysarthria), lack of coordination, spasticity, dystonic postures, and muscle rigidity.

Based on the clinical scenario provided, this patient most probably has impacted gall stones. Gall stones in children can be caused by haematological diseases such as sickle cell anaemia and thalassemia. Cholesterol stones are also becoming more prevalent. A dilated common bile duct (> 10mm in adults) suggests gall stone impaction. The presence of pyrexia indicates cholecystitis.

CF is inherited in an autosomal recessive manner.This means that to have CF, a person must have a mutation in both copies of the CFTR gene in each cell. People with CF inherit one mutated copy of the gene from each parent, who is referred to as a carrier.CF carriers can pass their copy of the CFTR gene mutation to their children. Each time two CF carriers have a child together, the chances are: 25 percent (1 in 4) the child will have CF50 percent (1 in 2) the child will be a carrier but will not have CF25 percent (1 in 4) the child will not be a carrier of the gene and will not have CFThis male’s parents are obligate carrier because he has a sibling with CFSo the chances he is a carrier too are 2 in 3The risk of having an affected child is the chance of both himself and his partner being carriers: (2/3 x 1/25 = 2/75) x 1/4 = 1/150.