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.

In a child with an age of 12 months – pincer grasp should be well developed. It is essential to have a good grasp of important milestones. Most 12-month-old children will be mobile, by standing holding onto a support, lifting one foot and moving it sideways (‘cruising’ around the furniture). They will demonstrate a neat pincer grasp, e.g. picking up a raisin or piece of paper between the tip of the index finger and the thumb. Words (or meaningful word-like utterances) are produced, but words are not usually chosen and put together deliberately by a child until after the second birthday (typically around the age of 30 months). Word combinations used earlier than this are likely to be an echo of a learnt phrase which may be understood by the child to be one single word even though they are a combination of more than one word (e.g. daddy, home). Building a tower of three cubes and following a one-step command such as ‘take off your socks’, is expected at 18 months.

In an acute and severe asthma attack the child cannot complete sentences in one breath because they are too breathless. The O2 saturation is less than 92% and PEF is between 33-50% best or predicted. In children that are 2-5 years old, HR is more than 140 bpm and more than 125 bpm in those older than 5 years old. The RR in children between 2-5 years old is more than 40/min, and more than 30/min in those older than 5 years old.

3,4-methylenedioxy-methamphetamine (MDMA) is a synthetic drug that alters mood and perception (awareness of surrounding objects and conditions). It is chemically similar to both stimulants and hallucinogens, producing feelings of increased energy, pleasure, emotional warmth, and distorted sensory and time perception. MDMA’s effects last about 3 to 6 hours, although many users take a second dose as the effects of the first dose begin to fade. Over the course of the week following moderate use of the drug, a person may experience:irritabilityimpulsiveness and aggressiondepressionsleep problemsanxietymemory and attention problemsdecreased appetitedecreased interest in and pleasure from sex

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.

The Meckel’s diverticulum is a vestigial remnant of the omphalomesenteric duct. This structure is also referred to as the vitelline and contains two types of ectopic tissue, namely| gastric and pancreatic.

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.

The clinical presentation is suggestive of congenital rubella syndrome. The classic triad of presenting symptoms includes sensorineural hearing loss, ocular abnormalities (cataract, infantile glaucoma, and pigmentary retinopathy) and congenital heart disease (patent ductus arteriosus and pulmonary artery stenosis). Other findings in congenital rubella syndrome include CNS abnormalities (mental retardation, behavioural disorders, encephalographic abnormalities, hypotonia, meningoencephalitis, and microcephaly), hepatosplenomegaly, and jaundice.

Risk factors for neonatal death and stillbirth (weak predictive value):- African American race- Advanced maternal age- History of fetal demise- Maternal infertility- History of small for gestational age infant- Small for gestational age infant- Obesity- Paternal age- Poverty and poor quality of careSo in this case the risk factor is the parental unemployment

Iron deficiency anaemia has the following laboratory characteristics: low haemoglobin, a low serum iron, a low serum ferritin, a low transferrin saturation, and a high total iron-binding capacity.

The clinical picture suggests intracranial haemorrhage which is uncommon but prevalent in pre-term babies. The rest of the options suggest peripheral causes which do not affect the central function.

Fanconi tubular syndrome is characterised by malabsorption of various electrolytes and substances commonly absorbed by the proximal tubule. Hypokalaemia, hypophosphatemia, and hyperchloremic metabolic acidosis is usually present. Also, urinalysis reveals an increased fractional excretion of glucose.

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.

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%.

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.

Multiple endocrine neoplasia type 1 is a rare, autosomal dominant disorder characterized by a higher propensity to develop various endocrine and nonendocrine tumours. The primary endocrine tumours that are a part of this disorder include carcinoid tumours and tumours of parathyroid, enteropancreatic, and anterior pituitary origin. Carcinoid tumours encountered in MEN type 1 are mostly of the foregut region. Non-endocrine tumours found in MEN type 1 include meningiomas and ependymomas, lipomas, angiofibromas, collagenomas, and leiomyomas. The pathogenesis of MEN type 1 is the inactivating mutation of the tumour suppressor gene MEN 1, which encodes the protein menin.

The most likely causative organism for the symptoms of this child is Giardia lamblia.Giardiasis results in fat malabsorption thus giving rise to greasy stools. It is resistant to chlorination, hence has a risk of transfer in swimming pools.World Health Organisation definitions- Diarrhoea: > 3 loose or watery stool per day- Acute diarrhoea < 14 days- Chronic diarrhoea > 14 daysConditions that usually present as acute diarrhoea:- Gastroenteritis: It may be accompanied by abdominal pain or nausea/vomiting.- Antibiotic therapy: Can occur following antibiotic therapy, especially common with broad spectrum antibiotics.Conditions that usually present as chronic diarrhoea:- Irritable bowel syndrome: It is a very common disease.The most consistent features are abdominal pain, bloating and change in bowel habit. Patients may be divided into those with diarrhoea predominant IBS and those with constipation-predominant IBS.Features such as lethargy, nausea, backache and bladder symptoms may also be present in these patients.- Ulcerative colitis: It presents as bloody diarrhoea. Patients can also present with crampy abdominal pain and weight loss. Faecal urgency and tenesmus may be seen.- Crohn’s disease: It is also associated with crampy abdominal pains and diarrhoea. Bloody diarrhoea less common than in ulcerative colitis. Other features include malabsorption, mouth ulcers perianal disease and intestinal obstruction – Colorectal cancer: It is very rare in children. The symptoms depend on the site of the lesion but include diarrhoea, rectal bleeding, anaemia and constitutional symptoms like weight loss and anorexia.- Coeliac disease: In children, it may present with failure to thrive, diarrhoea and abdominal distension.Other conditions associated with diarrhoea include thyrotoxicosis, laxative abuse, appendicitis, and radiation enteritis.

The baby needs more oxygen saturation which could be attempted by increasing the mean airway pressureAfter initial resuscitation and stabilization, the following should be the ventilator settings used:Rate: 30-40/minutePeak inspiratory pressure (PIP) – determined by adequate chest wall movement.An infant weighing less than 1500 grams: 16-28 cm H2O.An infant weighing greater than 1500 grams: 20-30 cm H2O. Positive end expiratory pressure (PEEP): 4 cm of H2O OR 5-6 cm if FiO2 > 0.90.FiO2: 0.4 to 1.0, depending on the clinical situation.Inspiratory time: 0.3-0.5 sec.After 15 to 30 minutes, check arterial blood gases and pH.If the PaO2 or the O2 saturation is below accepted standards, the FiO2 can be raised to a maximum of 1.0. If the PaO2 or O2 saturation is still inadequate, the mean airway pressure can be raised by increasing either the PIP, PEEP, inspiratory time or the rate, leaving inspiratory time constant.If the PaCO2 is elevated, the rate or peak inspiratory pressure can be raised.

Various types of birthmarks are commonly seen in children of different age groups. Birthmarks can be broadly classified as pigmented and vascular birthmarks. Port-wine stain (nevus flammeus) is an example of a vascular birthmark, and is characterized by a reddish-purple discoloration of the skin due to abnormal underlying skin vasculature. Port-wine stain has also been associated with vascular diseases like Sturge-weber syndrome, which is a congenital neurocutaneous disorder. In Sturge-weber syndrome, the port-wine stain affects the skin around the ophthalmic branch of trigeminal nerve.

Based on the presented clinical scenario, the most probable diagnosis for the patient would be testicular torsion.Rationale:The gubernaculum is the structure responsible for aiding the descent of the testicles from the abdomen into the scrotum. The processus vaginalis precedes the descent of the testes and then undergoes closure. Abnormalities such as the persistence of a patent processus vaginalis, known as bell clapper deformity, predispose to testicular torsion.Other options:- Varicocele: Nutcracker syndrome occurs where the left renal vein becomes compressed in between the superior mesenteric artery and the aorta. Since the left gonadal vein drains into the left renal vein, this results in a varicocele. – Epididymitis and mumps orchitis are differentials for acute testicular pain but are not due to a defect in the processus vaginalis. – An incarcerated inguinal hernia presents mainly with signs of bowel obstruction which are not mentioned in the clinical scenario.The descent of testes:- Until the end of foetal life, the testicles are located within the abdominal cavity. – They are initially located on the posterior abdominal wall on a level with the upper lumbar vertebrae (L2). – Attached to the inferior aspect of the testis is the gubernaculum testis which extends caudally to the inguinal region, through the canal and down to the superficial skin. – It is interesting to note that both the testis and the gubernaculum are extra-peritoneal.- As the foetus grows, the gubernaculum becomes progressively shorter. It carries the peritoneum of the anterior abdominal wall (the processus vaginalis). As the processus vaginalis descends the testis is guided by the gubernaculum down the posterior abdominal wall and the back of the processus vaginalis into the scrotum.- By the third month of foetal life the testes are located in the iliac fossae, by the seventh they lie at the level of the deep inguinal ring.Usually, the processus vaginalis closes after birth but may persist predisposing to indirect hernias. On the other hand, a partial closure may result in the development of cysts on the cord.

The CSF picture in bacterial meningitis has the following characteristics: several polymorphs, cells, protein that is maximum 5g/l, a few lymphocytes and glucose that accounts for the two thirds of the blood level.

The most commonly requested biochemistry tests for renal function are the urea and electrolytes. They supply important information when it comes to homeostasis and excretion. Glomerular filtration rate is also the essential standard marker of kidney health and is assessed by checking the creatinine levels. In this case as the child has lost fluids and electrolytes, this test will indicate the extent of the loss and allow for more appropriate replacement.

The median nerve is a peripheral nerve originating in the cervical roots C5–T1 of the brachial plexus. It supplies motor innervation to the anterior forearm flexors, the thenar muscles, and the two lateral lumbricals as well as sensory innervation to the lateral palm and anterior, lateral three and a half fingers. Motor and sensory deficits depend on whether the lesion is proximal (above the elbow) or distal (below the elbow). While proximal lesions present with the “hand of benediction,” distal lesions present with either the “pinch sign” (anterior interosseous nerve syndrome) or, in the case of carpal tunnel syndrome, with mildly impaired thumb and index finger motion. Both proximal lesions and carpal tunnel syndrome result in reduced sensation in the area of the thumb, index and middle finger. Anterior interosseus nerve syndrome does not cause any sensory deficits. Chronic injuries to the nerve result in atrophy of median nerve innervated muscles while acute injuries do not have this feature. Treatment is mostly conservative and focuses on rest and immobilization.

Epilepsy is a common paediatric neurologic disorder characterized by seizures of varying frequency and intensity. There are many childhood or infantile epilepsy syndromes that can be categorized as benign epilepsy syndromes as the child suffering from these usually outgrows them after reaching a certain age, and they do not lead to significant cognitive or physical impairment. Some of these may not need any treatment. Such benign epilepsy syndromes include benign rolandic epilepsy, Panayiotopoulos syndrome, Gastaut type-idiopathic childhood occipital epilepsy, and idiopathic photosensitive occipital lobe epilepsy. West syndrome, also called infantile spasms, is a serious infantile epileptic encephalopathy, characterized by multiple clusters of myoclonic spasms, and regression of the previous normally attained milestones. It is associated with severe cognitive and physical impairment, often leading to life long disability.

Key observations in the results:

1. Oxygen Saturation Step-Up:
   • There is a significant step-up in oxygen saturation from the right ventricle (72%) to the pulmonary artery (86%). This suggests the presence of left-to-right shunting of blood.
2. Pressure Differences:
   • The pressure in the pulmonary artery is elevated (53/13 mmHg), indicating pulmonary hypertension.

Differential Diagnosis:

1. Patent Ductus Arteriosus (PDA):
   • PDA can cause increased pulmonary blood flow, leading to a step-up in oxygen saturation in the pulmonary artery. The pulmonary artery pressures can also be elevated due to increased blood flow.
2. Primary Pulmonary Hypertension:
   • Typically presents with elevated pulmonary pressures but does not usually show a step-up in oxygen saturation.
3. Pulmonary Stenosis:
   • Would result in elevated right ventricular pressure but would not explain the step-up in oxygen saturation.
4. Septum Primum Atrial Septal Defect (ASD):
   • Would result in a step-up in oxygen saturation from the right atrium to the right ventricle, not between the right ventricle and pulmonary artery.
5. Tetralogy of Fallot:
   • Characterized by right ventricular outflow tract obstruction, VSD, right ventricular hypertrophy, and an overriding aorta. Oxygen saturation levels would typically be lower in the systemic circulation.

Intussusception is an urgent condition that must be excluded first as it may lead to life-threatening complications.

Graves disease is an autoimmune disorder in which patients present with thyrotoxicosis and related ophthalmopathy, and dermopathy. Many affected patients experience hyperthyroidism. Peak incidence of graves disease is after the 3rd decade of life and is more common in women than in men. Graves susceptibility is association with HLA-DR3. Clinical features of Graves disease include an increased metabolic rate, heat intolerance, irritability, weight loss despite increasing appetite, diarrhoea palpitations, chemosis, acropachy and onycholysis.

Complement activation plays a key role in the pathophysiology of SLE and it is recommended to continue monitoring serum levels of C3 and C4 to assess for disease activity. However, it is important to note that decreased serum complement is not consistently associated with disease flares.

Based on the clinical presentation, the pubic hair development is in Tanner stage 2.The Tanner stages for pubic hair are as follows:Stage 1 – pre-adolescentStage 2 – sparse hair that is long, slightly pigmented and downyStage 3 – hair spread over the junction of the pubes, darker and coarserStage 4 – adult-type hair, but the area covered is smaller than it is in an adult.Stage 5 – adult in quantity and type

The symptoms of a partial generalized seizure are consistent with this patient.