The mesonephric duct is one of the paired embryogenic tubules that drain the primitive kidney (mesonephros) to the cloaca. It also gives off a lateral branch forming the ureteric bud. In both the male and the female the Wolffian duct develops into the trigone of the urinary bladder. When the ducts are exposed to testosterone during embryogenesis, male sexual differentiation occurs: the mesonephric duct develops into the rete testis, the ejaculatory ducts, the epididymis, the ductus deferens and the seminal vesicles.

Damage to the left parietal lobe can result in what is called Gerstmann’s Syndrome. It includes right-left confusion, difficulty with writing (agraphia) and difficulty with mathematics (acalculia). It can also produce disorders of language (aphasia) and the inability to perceive objects normally (agnosia).Damage to the right parietal lobe can result in neglecting part of the body or space (contralateral neglect), which can impair many self-care skills such as dressing and washing. Right side damage can also cause difficulty in making things (constructional apraxia), denial of deficits (anosognosia) and drawing ability.Bi-lateral damage (large lesions to both sides) can cause Balint’s Syndrome, a visual attention and motor syndrome. This is characterized by the inability to voluntarily control the gaze (ocular apraxia), inability to integrate components of a visual scene (simultanagnosia), and the inability to accurately reach for an object with visual guidance (optic ataxia)Special deficits (primarily to memory and personality) can occur if there is damage to the area between the parietal and temporal lobes.Left parietal-temporal lesions can affect verbal memory and the ability to recall strings of digits. The right parietal-temporal lobe is concerned with non-verbal memory.Right parietal-temporal lesions can produce significant changes in personality.

Henoch-Schönlein purpura (HSP) rashes are commonly found on the legs, feet, and buttocks while Immune thrombocytopenia (ITP) rashes manifest predominantly on the lower legs. HSP happens following a sore throat while ITP usually happens following an URTI or Flu. HSP is an inflammation of a blood vessel (vasculitis) while ITP is immune mediated insufficiency of platelets.

Gastroesophageal reflux occurs in almost all infants, manifesting as wet burps after feeding. The spit-ups appear effortless and not particularly forceful.Infants in whom reflux has caused GERD have additional symptoms, such as irritability, feeding refusal, and/or respiratory symptoms such as chronic recurrent coughing or wheezing and sometimes stridor. Much less commonly, infants have intermittent apnoea or episodes of arching the back and turning the head to one side (Sandifer syndrome). Infants may fail to gain weight appropriately or, less often, lose weight.Incidence of gastroesophageal reflux increases between 2 months and 6 months of age (likely due to an increased volume of liquid at each feeding) and then starts to decrease after 7 months. Gastroesophageal reflux resolves in about 85% of infants by 12 months and in 95% by 18 months.

The sympathetic chain lies posterior to the parietal pleura. During a thorascopic sympathectomy, this structure will have to be divided. The intercostal vessels lie posteriorly. They may be damaged with troublesome bleeding but otherwise are best left alone as the deliberate division will not improve surgical access.The sympathetic nervous system:The cell bodies of the preganglionic efferent neurones lie in the lateral horn of the grey matter of the spinal cord in the thoracolumbar regions.The preganglionic efferents leave the spinal cord at levels T1-L2. These pass to the sympathetic chain.Lateral branches of the sympathetic chain connect it to every spinal nerve. These postganglionic nerves will pass to structures that receive sympathetic innervation at the periphery.Sympathetic chains:These lie on the vertebral column and run from the base of the skull to the coccyx.Clinical correlation:Interruption of the head and neck supply of the sympathetic nerves will result in an ipsilateral Horner’s syndrome.For the treatment of hyperhidrosis, the sympathetic denervation can be achieved by removing the second and third thoracic ganglia with their rami. Removal of T1 will cause a Horner’s syndrome and is therefore not performed.In patients with vascular disease of the lower limbs, lumbar sympathectomy may be performed, either radiologically or (more rarely now) surgically. The ganglia of L2 and below are disrupted. Care should be taken to preserve the L1 ganglion. If it is removed in male patients, ejaculation may be compromised.

As this boy was dry for a considerable period, there is a high chance of a secondary cause for the bed wetting, such as bladder infections, constipation, diabetes, psychological stress and hormonal problems etc. These have to be excluded.

The age of the patient and the presence of immature white blood cells are suggestive of leukaemia. Hodgkin’s disease is unlikely in this age group and it usually presents with lymphadenopathy. In HIV, immature white blood cells are not present in the blood.

The nerve supply to the tensor tympani is the mandibular nerve.The mandibular nerve is the only division of the trigeminal nerve that carries motor fibres.Tensor tympani is a muscle that lies in a bony canal just superior to the pharyngotympanic tube. It originates from the cartilaginous portion of the pharyngotympanic tube, the bony canal in which it sits, and the greater wing of the sphenoid bone. It inserts into the upper part of the handle of the malleus. When contracted, it pulls the handle of the malleus medially. This action increases the tension across the tympanic membrane, reducing the magnitude of vibrations transmitted into the middle ear. This dampens loud noises or noises produced by chewing. Tensor tympani is innervated through the nerve to tensor tympani, which arises from the mandibular nerve.Other options:- The vestibulocochlear nerve is the eighth cranial nerve. This nerve has two components, a vestibular division that carries balance information, and a cochlear division that carries hearing information.- The glossopharyngeal nerve is the ninth cranial nerve. It has a wide range of functions. It carries taste and sensation from the posterior third of the tongue, as well as sensation from the pharyngeal wall and tonsils, the middle ear, external auditory canal and auricle. It carries parasympathetic fibres that supply the parotid gland. It also supplies the baroreceptors and chemoreceptors of the carotid sinus and supplies the secretomotor fibres to the parotid gland.- The maxillary nerve carries only sensory fibres.- The facial nerve is the seventh cranial nerve. It supplies the muscles of facial expression, as well as stylohyoid, the posterior belly of digastric, and stapedius (the only other muscle associated with the middle ear). It carries taste from the anterior two-thirds of the tongue and sensation from part of the external acoustic meatus, parts of the auricle and the retro-auricular area. It provides secretomotor fibres which supply to the submandibular gland, sublingual gland (via chorda tympani nerve), nasal glands and lacrimal glands.

The blood-brain barrier (BBB) is a term used to describe the unique properties of the microvasculature of the central nervous system (CNS). CNS vessels are continuous nonfenestrated vessels, but also contain a series of additional properties that allow them to tightly regulate the movement of molecules, ions, and cells between the blood and the CNS.Blood vessels are made up of two main cell types: Endothelial Cells (ECs) that form the walls of the blood vessels, and mural cells that sit on the abluminal surface of the EC layer. The properties of the BBB are largely manifested within the ECs, but are induced and maintained by critical interactions with mural cells, immune cells, glial cells, and neural cells, which interact in the neurovascular unit.Astrocytes are a major glial cell type, which extends polarized cellular processes that ensheath either neuronal processes or blood vessels.This includes regulating the contraction/dilation of vascular smooth muscle cells surrounding arterioles as well as PCs surrounding capillaries. Astrocytes have been identified as important mediators of BBB formation and function because of the ability of purified astrocytes to induce barrier properties.

The most appropriate next step would be to request for an EEG (electroencephalogram).The two primary differential diagnoses for the clinical scenario presented would be night terrors (hypnopompic hallucinations) due to underlying narcolepsy or frontal lobe epilepsy.Though occult airway obstruction and obstructive sleep apnoea can cause sleep disturbances, the clinical scenario presented is more suggestive of neurological disorders.The hyper-motor activity, along with arm posturing (often dystonic in appearance) and multiple occurrences per night would favour epilepsy. The daytime somnolence could be secondary to the nocturnal seizures.

Vesicoureteral reflux is a common disorder in children but can result in kidney scarring following acute pyelonephritis. The gold standard diagnostic test to detect renal scars in children is 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy

Oligohydramnios is a deficiency in the amniotic fluid volume, measured via ultrasound. Maternal factors associated with oligohydramnios include conditions where there is placental insufficiency such as chronic hypertension, preeclampsia or a thrombotic disorder, post-term pregnancy, premature rupture of membranes, certain chromosomal abnormalities, and obstructions of the foetal urinary tract. On the other hand conditions that are associated with polyhydramnios (excess amniotic fluid) include maternal diabetes, multiple gestations, Rh incompatibility and pulmonary abnormalities.

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.

Jaundice is considered pathologic if it presents within the first 24 hours after birth. Although up to 60 percent of term new-borns have clinical jaundice in the first week of life, few have significant underlying disease.1,2 However, hyperbilirubinemia in the new-born period can be associated with severe illnesses such as haemolytic disease, metabolic and endocrine disorders, anatomic abnormalities of the liver, and infections. The risk factors here is the mothers blood ground which suggests the cause is fetal-maternal blood group incompatibility.

4-year-old milestonesSocial and EmotionalEnjoys doing new things Plays “Mom” and “Dad” Is more and more creative with make-believe play Would rather play with other children than by himself Cooperates with other children Often can’t tell what’s real and what’s make-believe Talks about what she likes and what she is interested in Language/CommunicationKnows some basic rules of grammar, such as correctly using “he” and “she” Sings a song or says a poem from memory such as the “Itsy Bitsy Spider” or the “Wheels on the Bus” Tells stories Can say first and last nameCognitive (learning, thinking, problem-solving)Names some colours and some numbers Understands the idea of counting Starts to understand time Remembers parts of a story Understands the idea of “same” and “different” Draws a person with 2 to 4 body parts Uses scissors Starts to copy some capital letters Plays board or card games Tells you what he thinks is going to happen next in a book Movement/Physical DevelopmentHops and stands on one foot up to 2 seconds Catches a bounced ball most of the time Pours, cuts with supervision, and mashes own food

The femoral artery is the one accompanying the femoral shaft, being the most important blood supplier of the leg. Femoral artery injury during a femur shaft fracture is quite common as a result of blunt trauma.

The level of statistical significance is often expressed as a p-value between 0 and 1. The smaller the p-value, the stronger the evidence that you should reject the null hypothesis.A p-value less than 0.05 (typically ≤ 0.05) is statistically significant. It indicates strong evidence against the null hypothesis, as there is less than a 5% probability the null is correct (and the results are random). Therefore, we reject the null hypothesis, and accept the alternative hypothesis.However, this does not mean that there is a 95% probability that the research hypothesis is true. The p-value is conditional upon the null hypothesis being true is unrelated to the truth or falsity of the research hypothesis.A lower p-value is sometimes interpreted as meaning there is a stronger relationship between two variables. However, statistical significance means that it is unlikely that the null hypothesis is true (less than 5%).To understand the strength of the difference between two groups (control vs. experimental) a researcher needs to calculate the effect size.

E. coli accounts for the majority of UTI’s in children. If this child responds well to treatment and has no recurrence of his symptoms, then no form of imaging is required, as per NICE advice for children aged 6 months to 3 years. Had the child been less than 6 months of age, then a USS at 6 weeks would be necessary.Other options:- Pseudomonas causes atypical UTI. This warrants ultrasonography within the acute illness phase as it may reflect an underlying pathology and DMSA at 4-6 months.- Recurrent UTI is defined as two or more episodes of pyelonephritis OR 1 pyelonephritis and one cystitis OR 3 or more cystitis. It requires USS at six weeks and DMSA at 4-6 months.- Septicaemia is a sign of an atypical UTI. This requires USS within the acute illness as it may reflect an underlying pathology and DMSA at 4-6 months.- Unwell 48hrs post antibiotics is a sign of an atypical UTI. This requires USS within the acute illness as may reflect underlying pathology and DMSA at 4-6 months.

Erythema nodosum (EN) is an acute, nodular, erythematous eruption that usually is limited to the extensor aspects of the lower legs. Chronic or recurrent erythema nodosum is rare but may occur.Currently, the most common cause of erythema nodosum is streptococcal infection in children and streptococcal infection and sarcoidosis in adults.The eruptive phase of erythema nodosum begins with flulike symptoms of fever and generalized aching. Arthralgia may occur and precedes the eruption or appears during the eruptive phase. Most lesions in infection-induced erythema nodosum heal within 7 weeks, but active disease may last up to 18 weeks. In contrast, 30% of idiopathic erythema nodosum cases may last more than 6 months. Febrile illness with dermatologic findings includes abrupt onset of illness with initial fever, followed by a painful rash within 1-2 days.

Hydrocephalus is a serious medical condition resulting from excessive accumulation of cerebrospinal fluid in the brain leading to abnormal pressure build-up inside the brain. Hydrocephalus can be categorized into two types according to the flow of CSF between the ventricles. When the CSF flows freely between the ventricles, but is blocked after it exits the ventricular system, the hydrocephalus is said to be a communicating hydrocephalus. When the flow of CSF within the ventricles is blocked, the resulting hydrocephalus is termed as obstructive, or non-communicating. The communicating hydrocephalus is caused by insufficient reabsorption of CSF in the subarachnoid space, which is also observed in cases of bacterial meningitis, in which inflammatory process leads to the thickening of the leptomeninges and thereby reduces CSF reabsorption. Arnold Chiari malformation is associated with obstructive hydrocephalus due to blocked ventricles. Congenital aqueduct stenosis causes the blockage of third and lateral ventricles. Congenital atresia of the foramen of Monro leads to blocked lateral ventricles and thus results in obstructive hydrocephalus. Tumour of the posterior fossa is associated with blockage of the fourth ventricle outflow.

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).

Arterial blood gas is useful for the evaluation of oxygen and carbon dioxide gas exchange, respiratory function including hypoxia, and acid/base balance. This will quickly indicate if assisted ventilation is required for this patient.

Anorexia nervosa is an eating disorder which is characterized by distorted self-image leading to abnormally decreased calorie intake. This disorder affects multiple bodily systems, including the skin, GI, and endocrine system. Due to extreme weight loss, patients with anorexia nervosa develop cold intolerance along with bluish discoloration of their fingers, nose, and ears, which is known as acrocyanosis. This phenomenon may be due to the shunting of the blood from the peripheries to the central body systems as a reaction to hypothermia. Other notable changes in the integumentary system include extreme dryness (xerosis), lanugo hairs, decubitus ulcers, and easy bruisibility.

Case control studies are used to determine the relationship between exposure to a risk factor and the resultant outcomes. It finds patients in the general population who have a certain condition and retrospectively searches for past exposure to possible risk factors for the disease. Controls are people who do not have the disease found in the general population. This type of study is useful for rare diseases, and is less time consuming to conduct. While cohort studies can be used to study rare diseases they measure the relative risk of developing the disease over time based on exposure. Ecological or cross-sectional studies attempt take a snapshot of a whole population, and thus are inappropriate for rare diseases as larger sample numbers are needed. A randomised control trial is better suited to determine the effect of an intervention.

The trigeminal nerve is responsible for the motor innervation of the muscles of mastication and well as providing sensory input for most of the head. In testing the function of this nerve, the jaw jerk reflex may be brisk in cases of upper motor neuron lesions, but is however absent in nuclear or infra nuclear lesions involving the trigeminal nerve. Other nerve reflexes include the gag reflex of the glossopharyngeal nerve, and the pupillary light reflex of the optic nerve.

Haemophilia A and haemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition.

Psoriasis is a chronic inflammatory skin disease that is mainly due to the interplay between keratinocytes, dermal vascular cells, and antigen-presenting cells. There are five main types of psoriasis based on the type and severity of the lesions it produces. A useful tool to determine the extent and severity of psoriasis is the Psoriasis Area and Severity Index (PASI) score, which takes into account the percentage of a specific area affected by psoriasis in combination with severity, which in turn is assessed by the presence of desquamation, induration, and erythema.

Immediate needle decompression of pneumoperitoneum is necessary to avoid tension pneumoperitoneum. Air reduction enema is the main stay of treatment for intussusception and is successful in around 90% of cases. A serious potential risk of this procedure is perforation of the colon and a pneumoperitoneum, leading to rapid distension of the abdomen and splinting of the diaphragm.

The most appropriate imaging modalities to be used in this child would be CT Head, C-spine and Abdomen/Pelvis and chest X-ray (CXR).The C-spine cannot be cleared, this alongside a multi-trauma presentation means a CT C-spine is indicated rather than X-rays alone. The imaging modality for blunt trauma to the chest is CXR| if this shows significant thoracic trauma, a CT chest should be considered. Other options:- CT Head and Abdomen/Pelvis with CXR and X-ray C-spine: This child is at risk of C-Spine injury following the mechanism of trauma. He had a reduced GCS, has undergone a multi-region trauma and is now intubated. NICE head injury guidelines, therefore, recommend using CT.- CT Head, C-spine and Abdomen/Pelvis X-rays: Imaging of the chest is required following blunt trauma and for endotracheal tube position.- MRI Head: If there were concerns of abnormal neurology, then spinal MRI could be considered.- Whole-body CT: It is not recommended in children in view of the high radiation doses.

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.