It is recommended that a woman wait one month after stopping isotretinoin before trying to become pregnant. Usually, isotretinoin is no longer found in a woman’s blood 4-5 days after the last dose and most of its by-products should be gone within 10 days after the last dose.

Diabetes ketoacidosis is one of the most serious and acute complications of diabetes. At the time of presentation and during treatment of diabetic ketoacidosis (DKA), several metabolic and electrolyte derangements can ultimately result in respiratory compromise. Most commonly, hypokalaemia, hypomagnesemia and hypophosphatemia can eventually lead to respiratory muscles failure. Furthermore, tachypnoea, hyperpnea and more severely, Kussmaul breathing pattern can develop. Also, hydrostatic and non-hydrostatic pulmonary oedema can occur secondary to volume shifts into the extracellular space and secondary to increased permeability of the pulmonary capillaries. The presence of respiratory failure in patients with DKA is associated with higher morbidity and mortality. Being familiar with the causes of respiratory compromise in DKA, and how to treat them, may represent better outcomes for patients with DKA.

Maternal and fetal toxoplasma infection may be avoided by advising pregnant women to wear gloves when gardening or handling cat litter and to cook meat thoroughly. Affected babies are treated with pyrimethamine, sulfadiazine, and folic acid.

During lumbar puncture, the first structures encountered by the needle are skin and subcutaneous tissue. But, since they are not provided in the options, the most superficial structure after them is the supraspinous ligament.Lumbar puncture is a procedure performed to obtain cerebrospinal fluid. The procedure is best performed at the level of L3/L4 or L4/5 interspace. During the procedure, the needle pierces the following structures in order from superficial to deep: Skin, subcutaneous tissue, supraspinous ligament, interspinous ligament, ligamentum flavum, the epidural space containing the internal vertebral venous plexus, dura, and arachnoid, finally entering the subarachnoid space. The supraspinous ligament connects the tips of spinous processes and the interspinous ligaments between adjacent borders of spinous processes.As the needle penetrates the ligamentum flavum, it causes a give. A second give is felt when the needle penetrates the dura mater and enters the subarachnoid space. At this point, clear CSF flows through the needle and can be collected for diagnostic purposes.

An odds ratio (OR) is a measure of association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. Odds ratios are most commonly used in case-control studies, however they can also be used in cross-sectional and cohort study designs as well (with some modifications and/or assumptions). Wherea = Number of exposed casesb = Number of exposed non-casesc = Number of unexposed casesd = Number of unexposed non-casesOR=(a/c) / (b/d) = ad/bc

Von Willebrand disease (VWD), a congenital bleeding disorder caused by deficient or defective plasma von Willebrand factor (VWF), may only become apparent on haemostatic challenge, and bleeding history may become more apparent with increasing age. Type 1 VWD (,30% of VWD) typically manifests as mild mucocutaneous bleeding. Type 2 VWD accounts for approximately 60% of VWD. Type 2 subtypes include: Type 2A, which usually manifests as mild-to-moderate mucocutaneous bleeding| Type 2B, which typically manifests as mild-to-moderate mucocutaneous bleeding that can include thrombocytopenia that worsens in certain circumstances| Type 2M, which typically manifests as mild-moderate mucocutaneous bleeding| Type 2N, which can manifest as excessive bleeding with surgery and mimics mild haemophilia A. Type 3 VWD (<10% of VWD) manifests with severe mucocutaneous and musculoskeletal bleeding.

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.

Upper respiratory tract infection when not treated accordingly can lead to otitis media and the patient presents with severe earache and fever.

Crigler-Najjar syndrome is a rare genetic disorder characterized by an inability to properly convert and clear bilirubin from the body.The hallmark finding of Crigler-Najjar syndrome is a persistent yellowing of the skin, mucous membranes and whites of the eyes (jaundice).There are two forms of this disorder: Crigler-Najjar syndrome type I, characterized by a nearly complete lack of enzyme activity and severe, even life-threatening symptoms| and Crigler-Najjar syndrome type II, characterized by partial enzyme activity and milder symptoms. Both forms are inherited as autosomal recessive traits and are caused by errors or disruptions (mutations) of the UGT1A1 gene.The symptoms of Crigler-Najjar syndrome type I become apparent shortly after birth. Affected infants develop severe, persistent yellowing of the skin, mucous membranes and whites of the eyes (jaundice). These symptoms persist after the first three weeks of life.Infants are at risk for developing kernicterus, also known as bilirubin encephalopathy, within the first month of life.Crigler-Najjar syndrome type II is a milder disorder than type I. Affected infants develop jaundice, which increases during times when an infant is sick (concurrent illness), has not eaten for an extended period (prolonged fasting) or is under general anaesthesia. Some people have not been diagnosed until they are adults. Kernicterus is rare in Crigler-Najjar syndrome type II, but can occur especially when an affected individual is sick, not eating or under anaesthesia

Angelman Syndrome is a genetic disorder that affects the nervous system. The features of this condition include intellectual disability, a delay in developmental milestones, and movement disorders. The features occur as a result of the deletion or mutation of the maternal copy of the UBE3A gene located on Chromosome 15q. Though individuals usually inherit one copy of this gene from each parent, only the maternal gene remains active in parts of the brain. This phenomenon is known as genetic imprinting, and is also seen in Prader-Willi syndrome.

Achondroplasia is one of the commonest forms of skeletal dysplasias that lead to dwarfism. Multiple skeletal deformities are associated with it but the common cranial abnormalities are macrocephaly, frontal bossing, depressed nasal bridge, narrowed foramen magnum, and the presence of communicating hydrocephalus. A prominent maxilla is not associated with achondroplasia.

Diagnostic criteria of PCOsAccording to the American Association of Clinical Endocrinologists, at least two of three of the criteria below are required for diagnosis of PCOS after excluding other causes of irregular bleeding and elevated androgen levels.Hyperandrogenism (clinical or laboratory)Oligo- and/or anovulationPolycystic ovaries on ultrasoundDiagnosis of PCOS is possible without the presence of ovarian cysts.Rule out any other causes of hyperandrogenism and anovulation.Blood hormone levels↑ Testosterone (both total and free) or free androgen index↑ LH (LH:FSH ratio > 2:1)Oestrogen is normal or slightly elevated A clinical picture of hyperandrogenism overrules any normal hormone levels and can fulfil a diagnostic criterium of PCOS.

Adenoid tissue sometimes swell as a result of fighting off the infection as germs are trapped in the adenoids. Adenoid enlargement is suspected.

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.

Most cases of Prader-Willi syndrome are not inherited, particularly those caused by a deletion in the paternal chromosome 15 or by maternal uniparental disomy. These genetic changes occur as random events during the formation of reproductive cells (eggs and sperm) or in early embryonic development. Affected people typically have no history of the disorder in their family.Rarely, a genetic change responsible for Prader-Willi syndrome can be inherited. For example, it is possible for a genetic change that abnormally inactivates genes on the paternal chromosome 15 to be passed from one generation to the next.Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating (hyperphagia) and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes (the most common form of diabetes).

At the age of 6 months, children can begin to be weaned off breastmilk and formula feeds. One healthy and inexpensive way to do this is through infant led weaning as opposed to the conventional spoon feeding method. Children are able to enjoy a variety of soft finger foods even before they grow teeth, so all food does not need to be pureed or sweet. Children should however not be given cow’s milk until the age of 1 year.

Incontinentia pigmenti is a genetic condition that affects females more than males. It usually manifests in the skin but can affect other parts of the body as well. It presents with a blistering rash that may evolve into wart-like growths. Hyperpigmentation and hair loss are also present, as well as eye and teeth abnormalities. Clinically there are three phases: 1- the bullous phase – crops of vesicles appear in the first 2 weeks of life|2- the papular phase – warty papules that flatten out over the skin| and 3- the hyperpigmented phase – pigmentary changes in the form of whorls and streaks that are hypo- and hyperpigmented in nature.

Infections of the superficial skin around the eyes are called periorbital, or preseptal, cellulitis. It is predominantly a paediatric disease. Erysipelas is a bacterial skin infection involving the upper dermis which extends into the superficial cutaneous lymphatics. Sinusitis is in sinuses. Orbital infections and conjunctivitis are within the eye.

There are 6 pharyngeal arches, the fifth does not contribute any useful structures and often fuses with the sixth arch. The structures arising from the aortic arches are as follows:First aortic arch: It regresses except for a very small part that gives rise to the maxillary artery.Second aortic arch: It regresses except for a very small part giving rise to the stapedial artery.Third aortic arch: This arch is the source of the common carotid artery and the proximal part of the internal carotid artery, and the external carotid which arises as a bud from this arch.Right Fourth aortic arch: Is the genesis of the proximal part of the right subclavian artery.Left Fourth aortic arch: Gives rise to the medial portion of the arch of the aorta.Fifth aortic arch: The fifth aortic arch regresses completely and very early in the development.Sixth aortic arch: Either of the sixth aortic arches divides into ventral and dorsal segments, and therefore, their derivatives also divide into these two segments.Right Sixth Arch:Ventral: Gives rise to the right pulmonary artery.Dorsal: It degenerates completely and loses its connection with the dorsal aorta.Left Sixth ArchVentral: It gives rise to the left pulmonary artery that goes to the left pulmonary bud.Dorsal: It forms a vital connection during intrauterine life between the left pulmonary artery and the arch of the aorta. This structure is called ductus arteriosus.

One of the most common congenital viral infections is cytomegalovirus infection. It is caused by herpesvirus type 5. The clinical features include failure to thrive, intellectual disability, epilepsy, and microcephaly. The most common clinical complication is sensorineural deafness. The drug of choice for the treatment of neonatal CMV infection is ganciclovir, an anti-viral drug that has shown to prevent deafness.

Protein energy malnutrition often presents in two common forms, Kwashiorkor and Marasmus. Kwashiorkor is characterised by a protein deficiency with an additional inadequate calorie intake. As a result, affected children present with oedema, muscular atrophy, and their weight for age is 60-80% of the expected weight. Their cutaneous tissue is however preserved. Marasmus on the other hand is characterised by a severe calorie deficiency leading to atrophy of the muscles and adipose tissue, with weight loss being less than 60% of the normal. In both cases, if the child is not promptly rehabilitated, the malnutrition could cause irreversible damage, such as hepatic, cardiac and renal impairments.

The most probable diagnosis for this patient is bilateral retractile testes. This a normal phenomenon in some pre-pubertal boys. Rationale:Testicular descent can continue until about 3-months of age. The pre-pubertal testis is small enough that with activation of the cremasteric reflex, they can enter the inguinal canal. This in itself is a normal finding providing the testis can be brought into the scrotum without tension and does not require surgical correction. With time the testis will lie within the scrotum. Orchidopexy for true undescended testis can be performed from 6-months of age. It is also warranted if the testes remain undescended or intra-abdominally leading to infertility.Other options:- An ascending testis is one, typically, following hernia or orchidopexy surgery that was in the testis but with time is within the inguinal canal and cannot be brought into the scrotum. Orchidopexy is required for this.- No surgery is required as when the testis enlarges with puberty it will remain within the scrotum.- The testes can be brought into the scrotum. Therefore they are not undescended.- The testes are retractile not ascending| ascending testis cannot be brought into the scrotum and would require orchidopexy.

The most appropriate procedure in the surgical management of this child would be to perform an appendicostomy for anterior continence enemas (Malone procedure).Idiopathic constipation leading to faecal incontinence is managed in a stepwise progression, first with laxatives such as movicol, enemas and stronger laxatives and in younger children inter-sphincteric injection of botox may be performed. Following this either anal irrigation or antegrade continence enemas are performed. Appendicostomy for anterior continence enemas allow colonic washouts and thereby rapid achievement of continence.Other options:- Defunctioning Ileostomy: Although an option in extreme cases, an ACE stoma would be more appropriate in this child.- Laparotomy for resection of the megarectum is performed if ACE stoma fails due to megarectum.- Left hemicolectomy is a procedure reserved for slow-transit colons to increase transit time.- Bishop-Koop stoma: It is a procedure of historical significance. It is a way of washing out and managing meconium ileus.

The pituitary gland synthesizes and releases various hormones that affect several organs throughout the body.The pituitary gland is entirely ectodermal in origin but is composed of 2 functionally distinct structures that differ in embryologic development and anatomy: the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary).The anterior pituitary has three main regions:Pars distalis: Where the main hormone production occursPars tuberalis: Joins the pituitary stalk arising from the posterior pituitary glandPars intermedia: Divides the anterior and posterior parts of the pituitary gland. The pars distalis forms the majority of the adenohypophysis and resembles a typical endocrine gland.

Orbital bone fracture: The child has sustained a head injury and subsequently describes a CSF rhinorrhoea (indicating a cerebro-spinal fluid leak). CSF rhinorrhoea can occur in skull or nasal bone fractures. Given the symptoms of loss of consciousness and headache, this child is more at risk of having suffered a skull fracture requiring emergency CT head investigation and specialist neurosurgical management. An ethmoid bone fracture may also present this way. A skull x ray would help to determine an air fluid level and indeed allow some visualisation of the nasal bones, though in children the nasal bones do not visualise well due to lack of fusion. Either way this child would need assessment in the nearest Emergency Department and the school would be expected to follow a ‘head injury’ protocol.

Umbilical vein catheterization utilizes the exposed umbilical stump in a neonate as a site for emergency central venous access up to 14 days old. Umbilical vein catheterization can provide a safe and effective route for intravenous delivery of medications and fluids during resuscitation.The indication for umbilical vein catheterization is when there is a need for IV access in a neonate for resuscitation, transfusions, or short-term venous access when otherwise unobtainable.

Live attenuated vaccines such as the MMR, should be avoided in HIV+ patients.

Minimal change glomerulonephritis presents with mild or benign urinalysis findings. However, proteinuria together with the presence of oval fat bodies are typical.Minimal change glomerulonephritis (nephropathy) accounts for most cases of childhood nephrotic syndrome and 20–25% of adult nephrotic syndrome.

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.

The skin lesion described is the typical presentation of a keloid scar.Keloid scars extend beyond the limits of the incision.Note:Surgical wounds are either incisional or excisional and either clean, clean-contaminated or dirty. The main stages of wound healing include:- Haemostasis:It occurs minutes to hours following injury. It is characterised by the vasospasm in adjacent vessels, platelet plug formation and generation of fibrin rich clot.- Inflammation: It occurs typically 1-5 days after the injury. Neutrophils migrate into the wound (this is often impaired in diabetes). Growth factors, including basic fibroblast growth factor and vascular endothelial growth factor, are released in this phase. Fibroblasts replicate within the adjacent matrix and migrate into wound, while macrophages and fibroblasts couple matrix regeneration and clot substitution.- Regeneration: It occurs typically between 7-56 days after the injury. The factors that stimulate this phase are platelet-derived growth factor and transforming growth factor. They stimulate fibroblasts and epithelial cells. Fibroblasts produce a collagen network. Furthermore, they cause angiogenesis and thus wound healing.- Remodelling: This is considered the longest phase of the healing process and may last up to one year (or longer). During this phase, fibroblasts become differentiated (myofibroblasts), and these facilitate wound contraction. Collagen fibres are remodelled, and microvessels regress, leaving a pale scar.Clinical correlation:Abnormal scar formation:- Hypertrophic scars:It is the condition where excessive amounts of collagen are produced within a scar. Nodules may be present histologically containing randomly arranged fibrils within and parallel fibres on the surface. The tissue itself is confined to the extent of the wound itself and is usually the result of a full-thickness dermal injury. They may go on to develop contractures.- Keloid scars: This is also a condition where excessive amounts of collagen occur within a scar. A keloid scar will typically pass beyond the boundaries of the original injury. They do not contain nodules and may occur following even trivial injury. They do not regress over time and may recur following removal.