The cells in the testes that secrete testosterone are the Leydig cells.Other cells in testes include:- Spermatogonia: These are undifferentiated male germ cells which undergo spermatogenesis in the seminiferous tubules of the testes.- Sertoli cells: They are a part of the seminiferous tubule of the testes, cells are activated by FSH and nourish developing sperm cells.- Myoid: They are squamous contractile cells which generate peristaltic waves, they surround the basement membrane of testes.- Fibroblasts: Cells which synthesise collagen and the extracellular matrix.

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.

Mongolian spots are, hyper-pigmented, non-blanching patches present on the back and gluteal region at birth. They are commonly found in African and Asian ethnic groups, and can also present in infants of Mediterranean and middle eastern descent. Though the spots usually disappear by puberty, some may persist into adulthood.

Based on the clinical scenario, the patient has features suggestive of acute otitis externa, which can be managed with topic antibiotics.Otitis externa:It can be classified as acute (< 3 weeks) or chronic (> 3 months). Frequent exposure to water, e.g. swimming, is a risk factor for the condition. Itching, pain, hearing loss and discharge are common complaints. Examination demonstrates oedema of the external auditory canal with discharge. Pain may be elicited on the movement of the tragus or pinna. First-line treatment is with topical drops/sprays for one week. Acidic preparations such as 2% acetic acid, antibiotic or combined antibiotic and corticosteroid preparations may be used (1% hydrocortisone and 0.3% gentamicin). Acetic acid can be used as the first-line treatment for mild cases without discharge or hearing impairment. On selecting an appropriate topical preparation remember that topical aminoglycosides are contraindicated if the tympanic membrane is perforated and that chloramphenicol ear drops cause contact dermatitis in approximately 10% of people. Clinoquinol, a combination of antibacterial and antifungal, may be preferred over aminoglycoside containing preparations due to the theoretical lower risk of ototoxicity and dermatitis. However, there is no clear evidence to support the use of one topical preparation over another.Other options:- Admit for IV antibiotics: First line management is with analgesia and topical antibiotic or combined antibiotic and corticosteroid preparations. Thus, IV antibiotics is not an appropriate action.- Oral antibiotics: Oral antibiotics like flucloxacillin or erythromycin are considered only for severe infections such as the spread of cellulitis beyond the ear canal. – Reassurance is not sufficient to treat these patients. They require topic antibiotic therapy.- Referral to ENT: Should be considered only in case of treatment failure. ENT referral can also be considered if there is cellulitis extending past the margin of the external ear canal, extreme pain or extensive swelling and discharge likely to require suction or the insertion of an ear wick. Urgent ENT referral is reserved for suspected cases of malignant otitis externa (with the extension of the condition into the adjacent bone and spreading osteomyelitis).

In this particular case, the symptoms and signs are suggestive for congenital dislocation of the hip. There are several risk factors present including, a breech delivery, female gender (female:male = 6:1) and oligohydramnios. It is also more common in the left hip than the right.

Familial/inherited short stature is the most likely and commonest factor resulting in short stature among the children. Klinefelter syndrome is characterised by tall stature, widely spaces nipples and infertility. Other factors include congenital heart disease, maternal deprivation and diabetes mellitus but these are the rare causes.

The child requires frequent BP evaluation every 15 to 30 minutes. Normalisation of his BP should be achieved in a 48h interval. An ophthalmology assessment is indicated to check for acute injury of the blood vessels in the eye due to the elevated blood pressure.

A supracondylar humerus fracture is a fracture of the distal humerus just above the elbow joint. The fracture is usually transverse or oblique and above the medial and lateral condyles and epicondyles. This fracture pattern is relatively rare in adults, but is the most common type of elbow fracture in children. They are historically associated with morbidity due to malunion, neurovascular complications, and compartment syndrome. Important arteries and nerves (median nerve, radial nerve, brachial artery, and ulnar nerve) are located at the supracondylar area and can give rise to complications if these structures are injured. Most vulnerable structure to get damaged is Median Nerve. Damage/occlusion of the brachial artery is the cause of an absent radial pulse.

Marfan syndrome is a disorder that affects the connective tissue in many parts of the body. Connective tissue provides strength and flexibility to structures such as bones, ligaments, muscles, blood vessels, and heart valves. The signs and symptoms of Marfan syndrome vary widely in severity, timing of onset, and rate of progression.This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.At least 25 percent of Marfan syndrome cases result from a new mutation in the FBN1 gene. These cases occur in people with no history of the disorder in their family.The two primary features of Marfan syndrome are vision problems caused by a dislocated lens (ectopia lentis) in one or both eyes and defects in the large blood vessel that distributes blood from the heart to the rest of the body (the aorta).Associations include:Tall statureLearning disability (50%)Lens subluxation (usually upwards)Femoral herniaHemivertebraeCardiac problems (Aortic/mitral regurgitation, aneurysms)Joint hypermobilityArachnodactyly

Compared to parametric tests, non parametric tests are seen to be less powerful as they often contend with fewer assumptions, and may use less information from the data. Sample sizes can be smaller. The samples do not have to follow a normal distribution as in parametric tests, and data may be ordinal, ranked or contain outliers that cannot be removed. Therefore nonparametric tests are well suited for these instances and do not need to be used as a last resort. They are not any more complex than parametric tests.

The patient shows features of neurofibromatosis. The most likely cause for hypertension in this patient would be renal artery stenosis.Note:Neurofibromatosis is an inherited autosomal dominant disorder which could have affected this girl’s father, and she appears to have the classic skin lesions. A renal bruit might be heard in these patients. Polycystic kidney disease can occur in association with tuberous sclerosis, which also has skin lesions associated (different from those described in this patient). Most causes of hypertension in childhood have underlying renal causes, and a renal ultrasound with doppler is the first-line investigation of choice. Even if this is normal, further imaging would be indicated here, for example, isotope renal scans and angiography.

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.

By the age of 3 months Jasmine should startle to loud noises, recognise her parents voices and turn to them when they are speaking, and should quiet down or smile at the sound of a familiar voice when crying. She should also cry when she is uncomfortable or irritated. By the time Jasmine is 9 months old she would begin to understand and respond to the word ‘no’ as well as other easy commands. She would be able vocalise and babble with repetitive sounds, and imitate adults’ playful sounds. She would be much less likely startled by loud noises.

Possible Zika virus infections have been identified in breastfeeding babies, but Zika virus transmission through breast milk has not been confirmed. Additionally, we do not yet know the long-term effects of Zika virus on young infants infected after birth. Because current evidence suggests that the benefits of breastfeeding outweigh the risk of Zika virus spreading through breast milk, CDC continues to encourage mothers to breastfeed, even if they were infected or lived in or travelled to an area with risk of Zika.

Based on the clinical scenario, the most likely underlying pathogen is the Epstein Barr virus (EBV).An Epstein Barr virus (EBV) infection most commonly results in upper respiratory tract symptoms with fever and sore throat. Lymphadenopathy is frequently palpable on examination. Splenomegaly may also occur, and for this reason, patients diagnosed with glandular fever should be advised to avoid contact sports for one month following diagnosis. The presence of petechiae on the soft palate is also associated with EBV infection. The vast majority of patients with active EBV infection will develop a widespread rash if given amoxicillin, therefore, phenoxymethylpenicillin (Penicillin V) is recommended for the treatment of a suspected bacterial throat infection to prevent this complication occurring for individuals who have EBV infection.Other options:- Coronavirus: This is one of the causes of the common cold and is frequently responsible for sore throats; however, in this case, the presenting features are more suggestive of an EBV infection.- Group A Streptococcus: Streptococci are classified into two main groups; alpha-haemolytic and beta-haemolytic. Group A Streptococcus belongs to the beta-haemolytic group. Group A streptococcal infection is a common cause of bacterial tonsillitis. It is possible that the child, in this case, had streptococcal tonsillitis and has had a drug reaction to the amoxicillin. However her age, flu-like symptoms and petechiae on her palate all point to an EBV infection and amoxicillin resulting in a rash.- Parainfluenza: Parainfluenza viruses are one of many causes of the common cold and can cause pharyngitis. They are the leading cause of viral croup.- Rhinovirus: Rhinoviruses are one of many causes of the common cold and are frequently responsible for sore throats; however, in this case, are other factors suggesting EBV infection.

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

Many of the symptoms favour blast cells: the patient’s young age; a reoccurring sore throat caused by neutropenia and abnormal lymphoblasts; pale conjunctiva due to reduced production of red blood cells (this is because the marrow has been occupied by blast cells). There are no risk factors present for aplastic anaemia, and congenital aplastic anaemia would present itself earlier in life. A bone marrow aspiration would be needed to confirm the diagnosis.

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.

Bilious (green) gastric aspirate or emesis indicates that the intestines are obstructed below the ampulla of Vater.Gastrointestinal (GI) endoscopy is actually considered an essential diagnostic and therapeutic technique. Upper GI endoscopy in neonatal age allows for exploration of the oesophagus, stomach and duodenum; instead lower GI endoscopy easily reaches the sigmoid-colon junction.

Due to breakdown of the red blood cell membrane in haemophilic patients, cholesterol crystals are formed by the lipids. On the other hand lipofuscin deposition does not occur in haemolysis or haemorrhage. Neutrophil accumulation suggests acute inflammation. Anthracotic pigment is an exogenous carbon pigment that deposits in the lung from dust. Russell bodies are intracellular accumulations of immunoglobins in plasma cells. Curschmann’s spirals and Charcot Leyden crystals are pathognomonic of asthma.

Androgen excess is one of the most common causes of advanced bone age. It usually occurs in precocious puberty or congenital adrenal hyperplasia.

The average age for girls to begin puberty is 11.The first sign of puberty in girls is usually that their breasts begin to develop.It’s normal for breast buds to sometimes be very tender or for one breast to start to develop several months before the other one.Pubic hair also starts to grow, and some girls may notice more hair on their legs and arms.After a year or so of puberty beginning, and for the next couple of years:girls’ breasts continue to grow and become fuller.Around 2 years after beginning puberty, girls usually have their first period,pubic hair becomes coarser and curlierunderarm hair begins to grow. From the time their periods start, girls grow 5 to 7.5cm (2 to 3 inches) annually over the next year or two, then reach their adult height.After about 4 years of puberty in girls:breasts become adult-likepubic hair has spread to the inner thighgenitals should now be fully developedgirls stop growing taller.

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.

Power calculations are a important step in study design and preparation, but do not directly help with the interpretation of the results. They are used to determine how many subjects are needed in order to avoid errors in accepting or rejecting the null hypothesis. These calculations are not usually complex and for the best results, the power of the test should be set to above 80%.

The patient’s clinical presentation is highly suggestive of Charcot-Marie-Tooth syndrome.It is a hereditary sensory and motor neuropathy. It is also the commonest cause of inherited peripheral neuropathy. The lower motor neuron signs are usually mild in childhood, the age of onset is very variable, and the distal weakness can take years to progress. It is not fatal and does not affect the normal life expectancy.

Among the given options, pituitary adenoma is an acquired anterior pituitary disorder which represent between 10 and 25% of all intracranial neoplasms.Other options:- Agenesis of the corpus callosum is characterised by the partial or complete absence of the corpus callosum. This condition is associated with pituitary hormone deficiencies.- Congenital disorders such as hydrocephalus or arachnoid cysts may be a cause of precocious puberty.- Pituitary hypoplasia and septo-optic dysplasia are congenital disorders of the pituitary gland.

An epidural hematoma occurs when there is bleeding between the dura mater (a tough fibrous layer of tissue between the brain and skull) and the skull bone. These occur when arteries are torn as a result of a blow to the head, and injury in the temple area is a common cause. Although the pattern of a lucid interval followed by later neurological symptoms is characteristic, only a minority of patients display this pattern of symptoms. Reported death rates from epidural hematoma vary widely, ranging from 5% to over 40%. Middle meningeal artery is frequently involved in such incidents.

Prevalence, sometimes referred to as prevalence rate, is the proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time.

The most appropriate next step in the management of this patient would be to use E45 cream instead of soap. Using a greasier emollient and an antihistamine at night can also be trialled..Management of eczema:Treatment of eczema can be problematic, and thus, parents should be advised regarding simple, everyday measures that can relieve the symptoms. These include:- Using non-biological washing powder- Wearing cotton clothes as opposed to artificial fibres- Avoiding the use of soaps or shampoos and using E45 Cream as an alternative.- Additional use of bath oil (e.g. Oilatum) is found to be beneficial.- Regular emollient use is recommended and essential. The aim is to keep the skin from feeling dry at any time of day. Sedating with older types of antihistamines at night does not help to reduce itching, but when used in large doses, they occasionally provide a sedative effect which may improve sleep. If all these measures are in use, but the eczema is still not controlled, the escalation of treatment would be appropriate. Note: There is no evidence for the benefit of topical antibiotics.

The primary intestinal loop is formed from the midgut which gives rise to the distal half of the duodenum, the jejunum, ascending colon, proximal two thirds of the transverse colon and the ileum.