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 sensitivity of a screening test can be described in a variety of ways, typically such as sensitivity being the ability of a screening test to detect a true positive, being based on the true positive rate, reflecting a test’s ability to correctly identify all people who have a condition, or, if 100%, identifying all people with a condition of interest by those people testing positive on the test.The specificity of a test is defined in a variety of ways, typically such as specificity is the ability of a screening test to detect a true negative, being based on the true negative rate, correctly identifying people who do not have a condition, or, if 100%, identifying all patients who do not have the condition of interest by those people testing negative on the test.Sensitivity=[a/(a+c)]×100Specificity=[d/(b+d)]×100a: True positiveb: False Positivec: False negatived: True negative

USG of the scrotum is important to exclude any abnormality with testicles, epididymis and scrotum. This presentation can be acute epididymo-orchitis or testicular torsion. USG of the scrotum will help to confirm the diagnosis.

The most probable diagnosis in this patient is Noonan syndrome.Noonan syndrome is an autosomal dominant condition characterised by short stature, heart defects (mainly pulmonary stenosis) and learning difficulties. An affected foetus can present with a significant increase in the nuchal thickness or a cystic hygroma of the neck. The condition is variable, and an affected parent is often only diagnosed after the diagnosis in the child.

Cystic fibrosis is a life-threatening disorder that causes the build up of thick mucus in the lungs, digestive tract, and other areas of the body. It is a hereditary autosomal-recessive disease caused by mutations of the CFTR gene. Cystic fibrosis eventually results in bronchiectasis which is defined as a permanent dilatation and obstruction of bronchi or bronchioles.

This history is suggestive of Henoch-Schönlein Purpura following a respiratory infection. A typical rash involving thighs and buttocks is often seen in this age group. Coagulation profile is the suitable answer from the given answers.

The most probable cause for the child’s presenting symptoms and the findings in ultrasound would be the presence of an abnormal posterior urethral valve. A posterior urethral valve is a developmental anomaly that usually affects male infants (incidence 1 in 8000) leading to obstructive uropathy. Diagnostic features include bladder wall hypertrophy, hydronephrosis and bladder diverticula.Note:Posterior urethral valves are the most common cause of infra-vesical outflow obstruction in males. They can be diagnosed on antenatal ultrasonography. Due to the necessity of the fetal bladder to develop high emptying pressures in utero secondary to this anomaly, the child may develop renal parenchymal damage. This leads to renal impairment noted in 70% of boys at the time of presentation. Management:The immediate treatment would be to place a bladder catheter to relieve the acutely retained urine. The definitive treatment of choice would be an endoscopic valvotomy with a cystoscopic and renal follow up.

The following methods are adopted for the treatment of DKA:

– Fluids: Bolus of 10 ml/kg of normal saline. Stop at three boluses to avoid precipitating cerebral oedema. The remaining deficit has to be corrected over 48 hours. Strict input/output, U&E, and pH monitoring is necessary in such patients.

– Insulin: Insulin infusion can be initiated at 0.05-0.1 unit/kg/hour. It is essential to monitor blood glucose closely, and the aim is to decrease by 2 mmol/hour.

– Potassium: Initially, it will be high, but following insulin administration, the levels drop quickly as K+ enters cells with glucose, and thus, replacement is almost always necessary.

– Acidosis: Bicarbonate is avoided unless pH is less than 7. Acidosis will get corrected with the correction of fluid and insulin deficits. The definitive treatment is directed towards correcting the underlying precipitants of DKA, e.g. sepsis, infections.

A not immunized patient with a clean wound requires an immediate vaccination against diphtheria, tetanus and polio, according to the Green Book of Immunisation against infectious disease. (The Green Book has the latest information on vaccines and vaccination procedures, for vaccine preventable infectious diseases in the UK.)

Dandy-Walker syndrome is characterised by symptoms of brain maldevelopment that are seen in this patient. A large cranium indicates hydrocephalus, and the hypotonia indicates poor limb development.

Recommended regimens3 NRTI (e.g., zidovudine, lamivudine, abacavir) OR2 NRTI (e.g., lamivudine + abacavir) AND1 NNRTI (e.g., efavirenz) OR1 PI (e.g., lopinavir) OR1 INI (e.g., raltegravir)

Drug withdrawal symptoms after a period of substance abuse can lead to a range of symptoms. Amphetamines are known to cause hypersomnia, hyperphagia, and irritability, as well as vivid dreams as a result of withdrawal. Similar symptoms are found in cocaine withdrawal. Alcohol withdrawal presents with symptoms such as insomnia, tremulousness and delirium. Ecstasy withdrawal includes irritation, mood swings, fatigue and insomnia. Heroin withdrawal presents with symptoms which include dilated pupils, insomnia, abdominal cramps and muscle aches. Withdrawal from prolonged cannabis use can cause depression, anxiety restlessness and insomnia.

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.

Intussusception is one of the common causes of intestinal obstruction in children, resulting from the invagination or telescoping of one segment of the bowel into the other distal segment. It may induce bowel ischemia and necrosis, as well. It can occur as a complication of Meckel’s diverticulum. It usually occurs proximal to the ileocecal valve, and the most common presentation is ileocecal. Early signs and symptoms include cramping abdominal pain, nausea, vomiting, and pulling legs up to chest area. First line treatment includes resuscitation with IV fluids and nasogastric tube. It responds well to air-enema, which is also diagnostic.

Urine culture and sensitivity is used to diagnose a urinary tract infection (UTI). A mid-stream clean catch urine sample is the most common type of sample collected. It is important to follow the clean catch process to have accurate results from an uncontaminated sample. Urine cultures can also check for infections of the bladder or kidney.

Non Epileptic attack disorder, also known as psychogenic non epileptic seizures, is a condition characterised by episodes of abnormal movement and behaviours that resemble seizures , but are not caused by electrical activity changes in the brain. It is believed that the disorder is caused by the brain’s response to overwhelming or stressful situations. In Jamila’s case, triggering conditions for her episodes may have been the absence of her mother, and the stress of her upcoming examinations. A diagnosis of generalised epilepsy is unlikely because this would require abnormal movement in all 4 limbs during an episode and a longer period of semi consciousness after. Cataplexy can also be ruled out as it does not involve a loss of consciousness which we see in Jamila’s case. Vasovagal syncope does not correspond with the history as there was no evidence of simultaneous collapse and responsiveness coupled with colour change and near spontaneous recovery when supine. A complex partial seizure may be possible in Jamila’s case, however the history of long duration, her eyes being tightly shut and the differences in presentation between the two episodes makes it less likely.

To quantify differences between percentages you can use Fisher’s exact test.Odds ratios, relative risks and number needed to treat are ways of quantifying differences between percentages in two groups, however are not in themselves significance tests.

Omega-shaped epiglottis is a characteristic feature in the X-ray of a patient with laryngomalacia.

Hirschsprung’s disease is characterized by congenital absence of the autonomic plexus (Meissner’s and Auerbach’s plexus) in the intestinal wall. Usually limited to the distal colon, it can occasionally involve the entire colon or even the small bowel. There is abnormal or absent peristalsis in the affected segment, resulting in continuous spasm of smooth muscle and partial/complete obstruction. This causes accumulation of intestinal contents and dilatation of proximal segment. Skip lesions are highly uncommon. This disease is seen early in life with 15% patients presenting in first month, 60% by 1 year of age and 85% by the age of 4 years. Symptoms include severe and complete constipation, abdominal distension and vomiting. Patients with involvement of ultra-short segments might have mild constipation with intervening diarrhoea. In older children, symptoms include failure to thrive, anorexia, and lack of an urge to defecate. On examination, an empty rectum is revealed with stool palpable high up in the colon. If not diagnosed in time, it can lead to Hirschsprung’s enterocolitis (toxic megacolon), which can be fulminant and lead to death. Diagnosis involves a barium enema or a rectal suction biopsy. Barium enema shows a transition in diameter between the dilated, normal colon proximal to the narrowed, affected distal segment. It is to be noted that barium enema should be done without prior preparation, which can dilate the abnormal segment, leading to a false-negative result. A 24-hour post-evacuation film can be obtained in the neonatal period – if the colon is still filled with barium, there is a high likelihood of Hirschsprung’s disease. Full-thickness rectal biopsy is diagnostic by showing the absence of ganglion cells. Acetylcholinesterase staining can be done to highlight the enlarged nerve trunks. Abnormal innervation can also be demonstrated by rectal manometry.

Bulimia nervosa is a condition in which a person is involved in binge eating and then purging. This patient has swollen parotid glands. The glands swell in order to increase saliva production so that the saliva lost in the vomiting is compensated. This patient also has thickened calluses on the back of her hand. This is known as Russell’s sign. This occurs because of putting fingers in the mouth again and again to induce the gag reflex and vomit. The knuckles get inflamed in the process after coming in contact with the teeth multiple times.

Germinal matrix/intraventricular haemorrhage (GM/IVH) is a complication of premature delivery that can result in life-long medical and developmental consequences. Although GM/IVH can occur in term infants, haemorrhage in this group of infants remains distinct from periventricular haemorrhage (PVH)/IVH of the preterm infant. Several acquired lesions of the central nervous system (CNS) specifically affect infants born prematurely and result in long-term disability, including GM/IVH, periventricular white matter injury (e.g., cystic periventricular leukomalacia [CPVL], periventricular haemorrhagic infarction [PVHI]), haemorrhage, and diffuse injury to the developing brain.The physical examination is usually negative in germinal matrix/intraventricular haemorrhage (GM/IVH). Occasionally, severe GM/IVH may present with nonspecific systemic findings suggestive of cardiovascular collapse.One subgroup of infants with GM/IVH presents with the following:- A sudden unexplained drop in haematocrit levels- Possible physical findings related to anaemia (e.g., pallor, poor perfusion) or haemorrhagic shockAnother subgroup of infants with GM/IVH presents with extreme signs, including the following:- A sudden and significant clinical deterioration associated with anaemia, metabolic acidosis, glucose instability, respiratory acidosis, apnoea, hypotonia, and stupor is present.Physical findings related to these signs include poor perfusion, pallor or an ashen colour, irregularities of respiratory pattern, signs of respiratory distress including retractions and tachypnoea, hypotonia, and altered mental status (e.g., decreased responsiveness, coma).Additional neurologic signs, such as fullness of the fontanelles, seizures, and posturing, may also be observed. Progression can be rapid and may result in shock and death.Extradural haemorrhage also known as an epidural hematoma, is a collection of blood that forms between the inner surface of the skull and outer layer of the dura, which is called the endosteal layer. They are usually associated with a history of head trauma and frequently associated skull fracture. The source of bleeding is usually arterial, most commonly from a torn middle meningeal artery.A subdural haemorrhage (or hematoma) is a type of bleeding that often occurs outside the brain as a result of a severe head injury. It takes place when blood vessels burst between the brain and the leather-like membrane that wraps around the brain (the dura mater). The pooling blood creates pressure on the surface of the brain, causing a variety of problems.

Keratosis pilaris most often affects the outer aspect of both upper arms. It may also occur on the thighs, buttocks and sides of the cheeks, and less often on the forearms and upper back. The distribution is symmetrical.The scaly spots may appear skin coloured, red (keratosis pilaris rubra) or brown (hyperpigmented keratosis pilaris). They are not itchy or sore.Macules are flat, nonpalpable lesions usually < 10 mm in diameter.Examples include freckles, flat moles, tattoos, and port-wine stains, and the rashes of rickettsial infections, rubella, measles (can also have papules and plaques), and some allergic drug eruptions.Papules are elevated lesions usually < 10 mm in diameter that can be felt or palpated. Examples include nevi, warts, lichen planus, insect bites, seborrheic keratoses, actinic keratoses, some lesions of acne, and skin cancers. Plaques are palpable lesions > 10 mm in diameter that are elevated or depressed compared to the skin surface. Plaques may be flat topped or rounded. Lesions of psoriasis and granuloma annulare commonly form plaques.Nodules are firm papules or lesions that extend into the dermis or subcutaneous tissue. Examples include cysts, lipomas, and fibromas.Vesicles are small, clear, fluid-filled blisters < 10 mm in diameter. Vesicles are characteristic of herpes infections, acute allergic contact dermatitis, and some autoimmune blistering disorders (e.g., dermatitis herpetiformis).Bullae are clear fluid-filled blisters > 10 mm in diameter. These may be caused by burns, bites, irritant contact dermatitis or allergic contact dermatitis, and drug reactions. Classic autoimmune bullous diseases include pemphigus vulgaris and bullous pemphigoid. Bullae also may occur in inherited disorders of skin fragility.

Patients with breast cancer develop clinical symptoms rather late at advanced tumour stages. Typical signs may include:Changes in breast size and/or shape| asymmetric breastsPalpable mass: typically a single, nontender, firm mass with poorly defined margins, most commonly in the upper outer quadrantSkin changes: Retractions or dimpling (due to tightening of the Cooper ligaments), Peau d’orange: skin resembling an orange peel (due to obstruction of the lymphatic channels): Redness, oedema, and pitting of the hair folliclesNipple changes: inversion, blood-tinged dischargeAxillary lymphadenopathy: firm, enlarged lymph nodes (> 1 cm in size), that are fixed to the skin or surrounding tissueIn advanced stages: ulcerations

Scaphoid fractures are regarded as fractures that are difficult to heal, so a classification system is needed taking different factors into account that should lead towards proper guidance to the healing time and management of these fractures. Popular classification criteria are Herbert, Russe, and Mayo classification systems. Herbert’s classification system is based on the fracture’s stability and proposes that all complete bicortical fractures (except for tubercle fractures) are unstable. Salter-Harris classification is used for categorizing epiphyseal fractures, while Delbert classification system is reserved for fractures of the proximal femur in children. Fractures of the ankles are classified using Ottawa rules, and Garland classification is used for supracondylar fractures in children.

ABC : Airway, breathing, circulation is the order of assessment in any patient that is unconscious and apnoeic.

Except Tetralogy of Fallot, the others are acyanotic heart diseases. The cyanotic spells and loss of consciousness are due to spasm of the infundibular septum, which acutely worsens the right ventricular outflow tract obstruction. The given murmur is due to a ventricular septal defect.

External oblique forms the outermost muscle of the three muscles comprising the anterolateral aspect of the abdominal wall. Its aponeurosis comprises the anterior wall of the inguinal canal.

The most common cause for acute bloody diarrhoea in a 10-year-old child is Campylobacter.Note:Campylobacter is the most common bacterial cause of gastroenteritis in the UK. It typically presents with bloody diarrhoea, fever, abdominal pain and vomiting. The primary source of Campylobacter is uncooked poultry. Treatment is generally supportive unless the child is immunosuppressed or the symptoms are persistent.Other options:- E. coli 0157:H7: It causes acute haemorrhagic diarrhoea, usually afebrile. It can lead to haemolytic uremic syndrome (haemolytic anaemia, acute renal failure and thrombocytopenia), which is the commonest cause of acute renal failure in children.- Rotavirus: It rarely causes bloody diarrhoea.- Salmonella and Yersinia: While they can cause bloody diarrhoea, they are much less common compared to Campylobacter.

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.

Haemophilia A has an X-linked recessive pattern of inheritance, meaning that is a 50% chance of having a son with haemophilia and 50% chance of the daughters being carriers of the haemophilia gene.