The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.

Topical benzoyl peroxide is used for the treatment of mild to moderate acne vulgaris. It is actually a peeling agent and it clears the pores and reduces the bacterial cell count.

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.

Perthes’ disease is a disease of the hip in children. It presents with pain that is typically located in the groin area. The pain is often present only during physical activity. Most children seek medical attention because of limping.

Osgood–Schlatter disease is pain caused by inflammation of the patella tendon at the tibial insertion.

Slipped upper femoral epiphysis occurs classically in adolescence (M:F = 3:2)

Give up to five back blows: hit them firmly on their back between the shoulder blades. Back blows create a strong vibration and pressure in the airway, which is often enough to dislodge the blockage.

Munchausen syndrome by proxy is a mental illness and a form of child abuse. The caretaker of a child, most often a mother or a father, either makes up fake symptoms or causes real symptoms to make it look like the child is sick. The person with MSP gains attention by seeking medical help for exaggerated or made-up symptoms of a child in his or her care. As health care providers strive to identify what’s causing the child’s symptoms, the deliberate actions of the mother or caretaker can often make the symptoms worse.The person with MSP does not seem to be motivated by a desire for any type of material gain. People with MSP may create or exaggerate a child’s symptoms in several ways. They may simply lie about symptoms, alter tests (such as contaminating a urine sample), falsify medical records, or they may actually induce symptoms through various means, such as poisoning, suffocating, starving, and causing infection.

Febrile seizures are convulsions that can happen when a child, most often between the ages of six months and three years, has a fever. They usually last for less than five minutes and although the child may lose consciousness, they are relatively harmless. However, sometimes they can last for up to 15 minutes and when they are termed complex febrile seizures.

This is probably a case of protein-induced allergic proctitis, due to dietary protein transmitted through the mother to the breast-fed child. The mother should go on a milk-free and soya-free diet but continue to breast-feed.

Neonatal hypoglycaemia is a serious condition that needs prompt attention and management. The accepted criteria to define neonatal hypoglycaemia is blood sugar levels less than 2.2mmol/L during the first 3 days of life and less than 2.5mmol/L later on. Multiple aetiologies and various risk factors are involved in causing hypoglycaemia in new-borns| the most common and important causes include prematurity, erythroblastosis fetalis, hypoxia at birth, sepsis, inborn errors of metabolism, hypopituitarism, and hyperinsulinism due to maternal diabetes. Inborn errors of metabolism that lead to persistent neonatal hypoglycaemia are maple syrup urine disease, glycogen storage disease, fatty acid enzyme deficiencies, and fructose intolerance. Phenylketonuria does not cause hypoglycaemia.

Puberty is a period of transitioning into adulthood by developing full reproductive potential by undergoing drastic physiological and psychological changes. For boys, it occurs around 9-16 years of age typically. The process of pubertal changes is usually divided into stages called tanner’s stages. The physiologic changes of puberty are initiated by the release of gonadotropin-releasing hormones from the hypothalamus, which then interact with numerous endogenous and environmental stimuli to bring about the physical pubertal features. Tanner stage 2 in boys is characterized by the thinning and reddening of the scrotal skin.The growth spurt of around 9cm per year is expected in boys, at the peak velocity.Testicular enlargement of >3cm commences puberty.Pubarche, in the absence of other secondary sexual characteristics, is pathological.Adrenarche is the increase in the secretion of adrenal androgens, occurring prior to increased gonadotropin release.

The deep peroneal nerve lies in the anterior muscular compartment of the lower leg and can be compromised by compartment syndrome affecting this area. It provides cutaneous sensation to the first web space. The superficial peroneal nerve provides more lateral cutaneous innervation.Origin: It originates from the common peroneal nerve, at the lateral aspect of the fibula, deep to peroneus longus. Root values of common peroneal nerve: L4, L5, S1, and S2.Course and relation: It pierces the anterior intermuscular septum to enter the anterior compartment of the lower leg. Following which, it passes anteriorly down to the ankle joint, midway between the two malleoli. It terminates in the dorsum of the foot.Throughout the course it innervates:- Tibialis anterior- Extensor hallucis longus- Extensor digitorum longus- Peroneus tertius- Extensor digitorum brevisAt its termination, it innervates the skin in the web space between the first and second toes.Actions performed by the muscles supplied by the nerve:- Dorsiflexion of ankle joint- Extension of all toes- Inversion of the foot

The inferior alveolar nerve supplies all the teeth of the respective hemimandible. It transverses the inferior alveolar canal and is a branch of the trigeminal nerve’s mandibular division. Therefore, in this case, the teeth of the right hemimandible will be numb.

Among the treatment options provided, the most appropriate would be prednisolone 1-2 mg/kg.Other options:- Dexamethasone 0.15 mg per kg is the correct dose based on new trials and BNF guidance.- Inhaled budesonide 2mg would be a more appropriate dose.- Nebulised adrenaline may also be used.Croup:Laryngotracheobronchitis caused most commonly by parainfluenza virus. It most commonly affects children between 6 months to 3 years.Seasonal peaks: Most prevalent in autumn and spring.It starts as viral URTI then progresses to barking cough and a hoarse cry. Stridor and respiratory distress may occur. The illness can last from two days to 2 weeks.Relevant differential diagnoses include epiglottitis (the child will be septic with high temp and drooling) and inhaled foreign body.All children with moderate/severe croup should be given one dose of oral dexamethasone.Further doses may be needed if children have rebound symptoms.

Mittelschmerz is midcycle abdominal pain due to leakage of prostaglandin-containing follicular fluid at the time of ovulation. It is self-limited, and a theoretical concern is treatment of pain with prostaglandin synthetase inhibitors, which could prevent ovulation. The pain of mittelschmerz usually occurs in the lower abdomen and pelvis, either in the middle or to one side. The pain can range from a mild twinge to severe discomfort and usually lasts from minutes to hours. In some cases, a small amount of vaginal bleeding or discharge might occur. Some women have nausea, especially if the pain is very strong.Diagnosis of pelvic pain in women can be challenging because many symptoms and signs are insensitive and nonspecific. As the first priority, urgent life-threatening conditions (e.g., ectopic pregnancy, appendicitis, ruptured ovarian cyst) and fertility-threatening conditions (e.g., pelvic inflammatory disease, ovarian torsion) must be considered. Many women never have pain at ovulation. Some women, however, have mid-cycle pain every month, and can tell by the pain that they are ovulating.As an egg develops in the ovary, it is surrounded by follicular fluid. During ovulation, the egg and the fluid, as well as some blood, are released from the ovary. While the exact cause of mittelschmerz is not known, it is believed to be caused by the normal enlargement of the egg in the ovary just before ovulation. Also, the pain could be caused by the normal bleeding that comes with ovulation.Pelvic inflammatory disease can be ruled out if the patient is not sexually active.

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.

People with Systemic Juvenile Idiopathic Arthritis (also known as Stills disease) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions. Rheumatoid factor and antinuclear antibodies are usually negative. Treatment is with non-steroidal anti-inflammatory drugs (NSAIDs) and the prognosis is better than for adult rheumatoid arthritis.In pauciarticular Still’s disease, antinuclear antibodies are present. Large joints are affected and most patients develop classic features of seronegative spondylarthritis.

The most probable cause for the patient’s symptoms would be pes anserine bursitis.Translated, pes anserinus means goose feet. It is the term used to describe the unified bursa enclosing the tendons of the sartorius, gracilis and semitendinous muscles inserting into the anteromedial proximal tibia.Pes anserine bursitis is common in people doing sports due to overuse injuries. The main sign is of pain in the medial part of the proximal tibia. As the McMurray test is negative, medial meniscal injury is excluded.

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.

Turner syndrome (TS) is one of the most common genetic disorders| occurs with an incidence of I: 2,500 female live births. It results from complete or partial chromosome X monosomy. TS is associated with abnormalities of the X chromosome and characteristic clinical features of short stature, gonadal dysgenesis, sexual developmental deficiencies, cardiac and/or renal defects, webbed neck, low-set ears, skeletal deformities including cubitus valgus, a propensity to ear infections and hearing deficits.

Insufficient surfactant production in premature infants leads to respiratory distress syndrome or surfactant deficient lung disease (SDLD), characterized by structurally immature lungs. There are many risk factors of this disease, some of them include male gender, caesarean section, infants of diabetic mothers, being the second born of the premature twins, perinatal asphyxia, sepsis, and hypothermia. Maternal hypertension is not a recognized risk factor for respiratory distress syndrome| instead, pregnancy-induced hypertension and chronic maternal hypertension are the protective factors against this disease.

Gait variations in children are usually physiologically normal and only become a cause of concern when they persist or are associated with pain or other medical symptoms. Genu varus, also known as knock knees causes an outward rotation of the leg, leading the toes pointing outwards. The condition usually resolves by the age of 18 months. In comparison, in- toeing occurs with genu varus. Metatarsus adductus is also associated with an inward pointing of the toes.

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.

Classic Kallmann syndrome (KS) is due to isolated hypogonadotropic hypogonadism. Most patients have gonadotropin-releasing hormone (GnRH) deficiency, as suggested by their response to pulsatile GnRH therapy. The hypothalamic-pituitary function is otherwise normal in most patients, and hypothalamic-pituitary imaging reveals no space-occupying lesions. By definition, either anosmia or severe hyposmia is present in patients with Kallmann syndrome.

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.

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

According to WHO, the treatment protocol in severely dehydrated children, is to infuse a bolus of isotonic crystalloid over 20-30 min at 30ml/kg to children less than 12 months of age followed by giving the remaining fluid over 5 hours for infants. Reference: World Health Organisation, the treatment of diarrhoea, a manual for physical and senior health workers.

Point mutations are the type of mutations in which only a single nucleotide of the DNA is either deleted, substituted or a new single nucleotide is inserted into the DNA, causing alterations in the original normal DNA sequencing. The examples of point mutations include hemochromatosis, sickle cell disease, and Tay-Sach’s disease. Huntington’s disease is a trinucleotide repeat disorder. Down’s syndrome is characterized by an extra copy of chromosome 21, while Klinefelter syndrome is marked by an extra X chromosome. Fragile X syndrome is also a trinucleotide repeat disorder.

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.

Individuals with Marfan syndrome are usually tall and slender, have elongated fingers and toes (arachnodactyly), loose joints, and have an arm span that exceeds their body height. Other common features include a long and narrow face, crowded teeth, an abnormal curvature of the spine (scoliosis or kyphosis), stretch marks (striae) not related to weight gain or loss, and either a sunken chest (pectus excavatum) or a protruding chest (pectus carinatum). Some individuals develop an abnormal accumulation of air in the chest cavity that can result in the collapse of a lung (spontaneous pneumothorax). A membrane called the dura, which surrounds the brain and spinal cord, can be abnormally enlarged (dural ectasia) in people with Marfan syndrome. Dural ectasia can cause pain in the back, abdomen, legs, or head. Most individuals with Marfan syndrome have some degree of near-sightedness (myopia). Clouding of the lens (cataract) may occur in mid-adulthood, and increased pressure within the eye (glaucoma) occurs more frequently in people with Marfan syndrome than in those without the condition.

Hirsutism is the growth of excess hair in androgen dependent areas or in a male pattern. The phenomenon is found in conditions where there is abnormal androgen action. This can occur in adrenal lesions including congenital adrenal hyperplasia, and Cushing syndrome, or a failure to produce adequate female hormones such as PCOS and premature menopause. Similarly, drugs such as anabolic steroids, danazol and minoxidil can also cause hirsutism. Delayed puberty is unlikely to cause hirsutism.