Unless given IV, a drug must cross several semipermeable cell membranes before it reaches the systemic circulation. Drugs may cross cell membranes by diffusion, amongst other mechanisms. The rate of diffusion of a substance is proportional to the difference in the concentration of the diffusing substance between the two sides of the membrane, the temperature of the solution, the permeability of the membrane and, in the case of ions, the electrical potential difference between the two sides of the membrane.

These cardiovascular findings are suggestive of coarctation of the aorta, which is common among patients with Turner’s syndrome. Physical features of Turner’s syndrome include a short neck with a webbed appearance, a low hairline at the back of the head, low-set ears, and narrow fingernails and toenails that are turned upward.Atrioventricular septal defect is the most common cardiac anomaly in Down’s syndrome. Structural heart defects at birth (i.e., ventricular septal defect, atrial septal defect, patent ductus arteriosus) are common in Edward’s syndrome. Pulmonary stenosis with or without dysplastic pulmonary valve and hypertrophic cardiomyopathy are common in Noonan’s syndrome. Supravalvar aortic stenosis and peripheral pulmonary stenosis are found in William’s syndrome.

The diagnosis of a post-splenectomy/hyposplenism blood picture can be made reliably by identifying Howell Jolly bodies in routine Wright-Giemsa stained blood and target cells. These are round basophilic bodies in red blood cells that represent residual nuclear material from marrow nucleated red cell precursors that are usually culled out by the spleen.These do not occur in individuals with normally functioning splenic tissue and their presence indicates either 1) an asplenic state or 2) hypofunctioning splenic tissue as might be seen in a patient with late-stage sickle cell anaemia. Their presence in an individual with splenomegaly leads to a narrow differential diagnosis and their absence in a splenectomised individual indicates accessory splenic Heinz bodies and poikilocytosis typically increase in a splenectomised individual and care must be taken not to overdiagnose haemolysis in such an individual.

Precocious puberty refers to the appearance of physical and hormonal signs of pubertal development at an earlier age than is considered normal.Most patients, particularly girls suspected of having central precocious puberty, are otherwise healthy children whose pubertal maturation begins at the early end of the normal distribution curveIn a series of more than 200 patients evaluated at a single medical centre, central precocious puberty occurred 5 times more often in girls than boys.GnRH-dependent precocious puberty is treated with GnRH agonists or Luteinizing Hormone Releasing Hormone (LHRH). Follow up every 4-6 months to ensure that progression of puberty has been arrestedFavourable signs include normalization of accelerated growth, reduction (or at least no increase) in size of breasts, and suppression of gonadotropin levels after a challenge of GnRHThe ideal testing frequency has not been established. Monitor bone age yearly to confirm that the rapid advancement seen in the untreated state has slowed, typically to a half year of bone age per year or less

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.

Neurofibromatosis type 2, also known as schwannomin, is an autosomal dominant genetic disease caused by mutation of the merlin gene located on chromosome 22. Merlin is a tumour suppressor protein, which is responsible for controlling cell shape, growth and adhesion, and is predominantly found in nervous tissue. Its mutation increases the risk of tumour development especially bilateral vestibular schwannomas, the hallmark of neurofibromatosis 2.

Hypopigmentation is a side-effect that is more likely to be due to eczema rather than topical steroids therapy.All the options provided are potential side-effects of topical steroid therapy. They are observed when the potency of the steroid used is too high, or the amount of drug used is too much.. FTU or fingertip unit application is what is recommended, with caution, in delicate areas such as the face. Hypopigmentation can occur in eczema and is a post-inflammatory response, in contrast to the total depigmentation which is seen in vitiligo. Chronic eczema causes lichenification of skin, where the epidermis is thickened, and not skin atrophy.

In the pattern of mendelian inheritance, X- linked dominant inheritance means that all who inherit the X chromosome will present with the condition. In the case of maternal x-linked inheritance, sons and daughters have an equal chance of inheriting the condition as there is a 50% chance of inheriting the defective X chromosome from their mother as opposed to a non affected X chromosome from their father. However, in paternal X-linked dominant inheritance, sons will be unaffected as they inherit a Y chromosome from their father while daughters are sure to inherit the defective X-chromosome.

Ehlers-Danlos Syndrome (EDS) is a group of genetic connective tissue disorders with over 13 clinical subtypes. Hyper-mobility is common to many of these subtypes. Vascular EDS is identified by thin, translucent skin prone to easy bleeding, as well as the risk of early arterial rupture, gastrointestinal perforation and uterine rupture. Those affected have dysmorphic features including a thin nose and lips, sunken cheeks and large eyes. The other features including; atrophic scars, a dominant family history, hyper extensible skin and kyphoscoliosis are not specific to vascular EDS and overlap in many of the subtypes.

Increasing the volume of the TV and the child’s loss of hearing may suggest that he has otitis media with effusion but the fever and the ear pain strongly points to otitis externa as the diagnosis.

The most probable diagnosis for this patient would be Kawasaki disease.Kawasaki disease:It is an acute systemic disorder of childhood that predominantly occurs in Japan (800 cases per million in children under the age of 5 years). The causative factor is not known, but mycoplasma and HIV infection may be associated in some cases. Clinical Features:The principal clinical features are fever persisting for more than five days, bilateral non-purulent conjunctival congestion, cervical lymphadenopathy, polymorphous rash, arthralgia, palmar erythema and strawberry tongue. Other options:- Diffuse cutaneous systemic sclerosis is associated with skin, renal and gut involvement. Arthralgia, morning stiffness and flexor tenosynovitis are common. – Behcet syndrome is a vasculitis of unknown aetiology that characteristically targets venules. – Felty syndrome is the association of splenomegaly and neutropenia with rheumatoid arthritis. Lymphadenopathy is common, and there is a predisposition to recurrent infections.

Doctors must perform an infection screen and treat with intravenous antibiotics for at least 48 hours pending results to prevent neonatal sepsis. Risk factors for neonatal sepsis include rupture of the membranes. Risk factors for neonatal sepsis include rupture of membranes greater than 12-24 hours, intrapartum maternal pyrexia (> 38°C), fetal tachycardia, chorioamnionitis, pre-term birth and maternal colonisation with group B Streptococcus. In this case there are two risk factors: prolonged rupture of membranes, and pre-term birth.

This child is experiencing delayed speech. By the age of 2, a child should be able to combine at least 2 words to make a very simple sentence.

The management of cystic fibrosis requires a multidisciplinary approach, starting with a planned diet.The critical points of this management approach are:Chest physiotherapy and postural drainage – the parents are usually taught to do this.Deep breathing exercises,High calorie, high fat intake with vitamin supplementation.Pancreatic enzyme supplements with meals.Heart-lung transplantation would be the definitive treatment.Note: Previously, a high-calorie, low-fat diet was recommended to reduce steatorrhea. However, it is no longer the desired approach.

Based on the clinical scenario, the most probable diagnosis for this patient is pancreatitis.Although rare in childhood, the presence of abdominal pain radiating to the back with shock and tachycardia, and a raised amylase, should raise a suspicion of pancreatitis. Possible causes include trauma, drugs, viral illness, mumps, hyperparathyroidism, hyperlipidaemia and cystic fibrosis. Other options:- Normal LFTs in this patient make hepatitis unlikely. – Gastroenteritis with severe diarrhoea and vomiting may account for the shock and tachycardia, but guarding on abdominal examination and the raised amylase would not be explained by gastroenteritis. – Pregnancy is an important diagnosis to consider in an adolescent with abdominal pain, but the raised amylase and other features point to a diagnosis of pancreatitis.

Foreign body aspiration (FBA) commonly occurs in children aged 1-3 years. FBA typically presents with sudden onset of coughing and choking, followed by stridor and dyspnoea. Obstruction of the larynx or trachea is a potentially life-threatening situation that causes severe respiratory distress, cyanosis, and suffocation. Most commonly, the foreign body (FB) becomes lodged in the main and intermediate bronchi; approx. 60% of FB are located in the right main bronchus due to the more vertical orientation compared to the left main bronchus. Reduced breath sounds on the one side only would not be explained by a tracheal obstruction as it would cause reduced breath sounds bilaterally and a more severe clinical picture.

Answer: RicketsRickets is a disease of growing bone that is unique to children and adolescents. It is caused by a failure of osteoid to calcify in a growing person. The signs and symptoms of rickets can include:pain -the bones affected by rickets can be sore and painful, so the child may be reluctant to walk or may tire easily; the child’s walk may look different (waddling)skeletal deformities -thickening of the ankles, wrists and knees, bowed legs, soft skull bones and, rarely, bending of the spinedental problems -including weak tooth enamel, delay in teeth coming through and increased risk of cavitiespoor growth and development -if the skeleton doesn’t grow and develop properly, the child will be shorter than averagefragile bones -in severe cases, the bones become weaker and more prone to fractures.Marfan syndrome (MFS) is a genetic disorder of the connective tissue. The degree to which people are affected varies. People with Marfan tend to be tall and thin, with long arms, legs, fingers and toes. They also typically have flexible joints and scoliosis. The most serious complications involve the heart and aorta, with an increased risk of mitral valve prolapse and aortic aneurysm. Other commonly affected areas include the lungs, eyes, bones and the covering of the spinal cord.Ehlers-Danlos syndrome is a group of inherited disorders that affect your connective tissues – primarily your skin, joints and blood vessel walls. People who have Ehlers-Danlos syndrome usually have overly flexible joints and stretchy, fragile skin. This can become a problem if you have a wound that requires stitches, because the skin often isn’t strong enough to hold them.A more severe form of the disorder, called Ehlers-Danlos syndrome, vascular type, can cause the walls of your blood vessels, intestines or uterus to rupture. Osteoporosis is a disease in which bone weakening increases the risk of a broken bone. It is the most common reason for a broken bone among the elderly. Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. Chronic pain and a decreased ability to carry out normal activities may occur following a broken bone.Osteoporosis may be due to lower-than-normal maximum bone mass and greater-than-normal bone loss. Bone loss increases after menopause due to lower levels of oestrogen. Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, kidney disease, and surgical removal of the ovaries.

Advanced paternal age is associated with poor quality sperm leading to a reduction in overall fertility along with an increase in the occurrence of various medical disorders in the fetus. Advanced paternal age has been implicated as a risk factor for diseases like retinoblastoma, Marfan’s syndrome, neurofibromatosis, achondroplasia, autism spectrum disorders, schizophrenia, and acute lymphoblastic leukaemia. Down’s syndrome is mostly considered a consequence of advanced maternal age, but advanced paternal age has also been implicated as a risk factor. Turner syndrome is not found to be caused by advanced paternal age.

Patent ductus arteriosus is a heart defect that occurs in around 50% of the preterm or low birth weight infants. It is characterized by the failure of the fetal ductus arteriosus to close after birth. There are certain risk factors which predispose an infant to a patent ductus arteriosus. The most important risk factor is trisomy 21 or Down’s syndrome, which is associated with multiple cardiac defects. Other factors are congenital rubella syndrome, birth at high altitudes, and female gender.

The presentation of the child is highly suggestive of Henoch-Schonlein purpura (HSP). It is an IgA-mediated, autoimmune hypersensitivity vasculitis that targets the small vessels of the skin, GI tract, kidneys, and joints.It is most commonly seen in children aged 3 – 6 years old and is twice as common in boys than girls. Preceding viral URTI with low-grade pyrexia is common. The most common organism associated with HSP is, however, Group A streptococcal infection.A purpuric rash is seen on the back of the legs and buttocks and can less frequently affect the arms. Arthralgia is common (usually knees/ankles) in these patients.Abdominal pain and bloody diarrhoea may occur. And half of the children with HSP have renal involvement. Rarely, it can lead to end-stage renal failure.Treatment includes adequate hydration, occasionally steroids, and other immunosuppressants. The disease can recur in 1 in 3 children.

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 best answer is Polycystic Ovarian Syndrome (PCOS), supported by amenorrhea, obesity and acne. High insulin levels are indicative of PCOS and exclude Cushing syndrome (as this is associated with low insulin levels).

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.

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 mineť and hisť or hersť – 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,ť on,ť and underť – Says first name, age, and sex- Names a friend – Says words like I,ť me,ť we,ť and youť 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 twoť 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.

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.

Minimal change disease is a type of glomerulonephritis that mostly affects younger children. Proteinuria is present which leads to body oedema. But in these patients blood pressure is normal.

Certain infections and medications cause characteristic skin lesions, which are the result of hypersensitivity reactions to these agents. A skin rash characterized by the eruption of macules, papules, and target-like circular lesions is referred to as erythema multiforme. The target or iris lesions appear rounded with a red centre surrounded by a pale ring, which in turn is surrounded by a dark red outer ring. These are acute and self-limiting with a propensity for distal extremities. The most common infectious cause is the infection with herpes simplex virus 1 and 2 to a lesser extent. Other notable infectious causes of erythema multiforme include Mycoplasma pneumoniae, cytomegalovirus, HIV, hepatitis c virus, varicella zoster virus, adenovirus, and some fungal infections. Norovirus infection has not been implicated in the aetiology of erythema multiforme.

In the pattern of mendelian inheritance, X- linked dominant inheritance means that all who inherit the X chromosome will present with the condition. In the case of maternal x-linked inheritance sons and daughters have an equal chance of inheriting the condition as there is a 50% chance of inheriting the defective X chromosome from their mother as opposed to a non affected X chromosome from their father. However in paternal X-linked dominant inheritance, sons will be unaffected as they inherit a Y chromosome from their father while daughters are sure to inherit the defective X-chromosome.

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

Immunoglobulin G (IgG) glomerular immune deposits are seen more commonly in HSP compared to IgA nephropathy.The presentation of the child is highly suggestive of Henoch-Schonlein purpura (HSP). It is an IgA-mediated, autoimmune hypersensitivity vasculitis that targets the small vessels of the skin, GI tract, kidneys, and joints.It is most commonly seen in children aged 3 – 6years and is twice as common in boys than girls. Preceding viral URTI with low-grade pyrexia is common. The most common organism associated with HSP is, however, Group A streptococcal infection A.A purpuric rash is seen on the back of the legs and buttocks and can less frequently, affect the arms. Arthralgia is common (usually knees/ankles) in these patients. Abdominal pain and bloody diarrhoea may occur. And half of the children with HSP have renal involvement. Rarely, it can lead to end-stage renal failure.Treatment includes adequate hydration, occasionally steroids, and other immunosuppressants. The disease can recur in 1 in 3 children.