A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing a cross-section at intervals through time.
The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Relative risk is used in the statistical analysis of the data of experimental, cohort and cross-sectional studies, to estimate the strength of the association between treatments or risk factors, and outcomes.

Cardiac notch: is an indentation on the left lung of the heart.
Coronary sinus: a venous sinus on the surface of the heart (the posterior aspect) that receives blood from the smaller veins that drain the heart.
Coronary sulcus: a groove on the heart between the atria and ventricles.
Transverse pericardial sinus: located behind the aorta and pulmonary trunk and anterior to the superior vena cava.
Oblique pericardial sinus: located behind the left atrium. Accessed from the inferior side (or the apex) of the heart upwards.
Horizontal pericardial sinus: this is a made-up term.

Internal abdominal bleeding is most probably the cause of the child’s shock, especially unresponsive to fluid boluses.

The most probable diagnosis for this patient would be Edward syndrome.Edward syndrome results from trisomy 18. It is the second most common syndrome after Down syndrome. 60% of cases die within 48 hours, and 90% within the first year due to apnoeas. Cardiovascular abnormalities include atrial septal defect, ventricular septal defect and a persistent ductus arteriosus. There is no association with exophthalmos, but it may occur. Right choroid plexus cysts are found on coronal imaging, and 40–70% at post mortem are shown to have multiple large bilateral choroid plexus cysts (>10 mm). These may not become pathological but usually trigger an anomaly scan. Around 1% of cases may present with only a cyst, but 4% may present with other abnormalities.Other options:- Children with the velocardiofacial syndrome have a classic facial appearance with hypertelorism, a tubular nose, a cleft lip/palate abnormality and cardiac anomalies. – Children with Patau syndrome usually present with midline defects and are less likely to have rocker-bottom feet. – Children with Treacher Collins syndrome present with abnormalities of the branchial arches and pharyngeal pouches.

This is the clinical picture of dermatitis herpetiformis associated with gluten-sensitive enteropathy. To establish the diagnosis, you should measure the coeliac antibodies. Darrier’s sign (where the skin urticates when it is stroked) is positive in urticaria pigmentosa.

A case–control study (also known as case–referent study) is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case–control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the cases) with patients who do not have the condition/disease but are otherwise similar (the controls).
An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of A in the presence of B and the odds of A in the absence of B or vice versa.

The sensory innervation of the external auditory meatus is provided by branches of several cranial nerves. The auriculotemporal branch of the mandibular nerve (CN V3) with the nerve to external acoustic meatus supplies the anterior and superior wall of the canal with sensory innervation. The auricular branch of the vagus nerve (CN X) supplies the posterior and inferior walls of the canal, and the facial nerve (CN VII) may also supply it due to its connection with the vagus nerve.

The paired sample t-test, sometimes called the dependent sample t-test, is a statistical procedure used to determine whether the mean difference between two sets of observations is zero. In a paired sample t-test, each subject or entity is measured twice, resulting in pairs of observations. Common applications of the paired sample t-test include case-control studies or repeated-measures designs.Statistical significance is determined by looking at the p-value. The p-value gives the probability of observing the test results under the null hypothesis. The lower the p-value, the lower the probability of obtaining a result like the one that was observed if the null hypothesis was true. Thus, a low p-value indicates decreased support for the null hypothesis. However, the possibility that the null hypothesis is true and that we simply obtained a very rare result can never be ruled out completely. The cut-off value for determining statistical significance is ultimately decided on by the researcher, but usually a value of .05 or less is chosen. This corresponds to a 5% (or less) chance of obtaining a result like the one that was observed if the null hypothesis was true.

Alopecia is a scalp condition characterized by either overall baldness or patches of hair loss over the head. It can be broadly classified as scarring alopecia and non-scarring alopecia. Non-scarring is the most common type and is seen in various conditions like nutritional deficiencies, alopecia areata, hypothyroidism, tinea capitis, and SLE. Scarring alopecia is commonly seen in cases of discoid lupus erythematosus, which is a common cause of widespread inflammatory and scarring lesions all over the body and scalp.

The history is suggestive of a post-traumatic seizure which frequently occurs after moderate or severe traumatic brain injury. Although upgoing plantars can be identified in a post-ictal status, an intracranial bleed has to be excluded. A single seizure cannot be considered epilepsy

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.

Tuberous sclerosis presents with the growth of numerous noncancerous (benign) tumours in many parts of the body. They may appear in the brain, kidneys, skin or various other organs.

Ectoderm derivatives include the adrenal medulla, posterior pituitary, the epidermis of the skin, nails, hair, sweat glands, mammary glands, sebaceous glands, the central nervous system, the peripheral nervous system, the retina and lens of eye, the pupillary muscle of the iris, melanocytes, Schwann cells and odontoblasts.

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.

Generally, bed-wetting before age 7 isn’t a concern as the child may still be developing night-time bladder control. The child is less than 5 years and most children will outgrow bed-wetting on their own. Therefore only reassurance and behavioural therapy are suggested at this stage.

The child has a history of pharyngitis followed 10 days later by signs of glomerulonephritis. In this particular case, it is most probably a post-streptococcus glomerulonephritis which accounts for 80% of paediatric cases of glomerulonephritis.

HbA1c stands for glycated haemoglobin. In patients with haemolytic diseases associated with a shortened RBC survival, HbA1c levels can be unusually low despite controlled diabetes mellitus.These haemolytic diseases can include glucose-6-phosphate dehydrogenase deficiency and sickle cell anaemia.HbA1c:It is a measure of non-enzymatic glycation which occurs due to haemoglobin’s exposure to plasma glucose. As plasma glucose increases so does HbA1c.The level of HbA1c quantitively assesses the control of diabetes mellitus over the last 120 days (as this is the life span of a red blood cell).Haemoglobin type A is separated on cation exchange chromatographyOther subsections include HbA1O, HbA1a, HbA1b.According to the updated NICE recommendations (2015):The target level of HbA1c in children with T1DM is 48 mmol/mol (6.5%) or lower. It is monitored every three months. Better control is associated with fewer long term complications

Erb’s palsy is a paralysis of the arm caused by injury to the brachial plexus, specifically the severing of the upper trunk C5–C6 nerves.The infant with an upper plexus palsy (C5-C7) keeps the arm adducted and internally rotated, with the elbow extended, the forearm pronated, the wrist flexed, and the hand in a fist. In the first hours of life, the hand also may appear flaccid, but strength returns over days to months.The right side is injured in 51% of cases. Left side occurs in 45% of patients and bilateral injuries, in 4%.

Transposition of the great arteries (TGA) is a common congenital heart lesion that presents with severe cyanosis that is likely to appear in the first day of life.

Diabetes insipidus (DI) is defined as the passage of large volumes (>3 L/24 hr) of dilute urine (< 300 mOsm/kg). It has the following 2 major forms:Central (neurogenic, pituitary, or neurohypophyseal) DI, characterized by decreased secretion of antidiuretic hormone (ADH| also referred to as arginine vasopressin [AVP])Nephrogenic DI, characterized by decreased ability to concentrate urine because of resistance to ADH action in the kidney.The boy most probably has nephrogenic diabetes insidious (DI) not central DI so he is not responding to the ADH treatment.

Excessive weight loss is generally indicative of suboptimal feeding, and infants with excessive weight loss are potentially dehydrated or at risk of dehydration.Jaundice associated with suboptimal breastfeeding– this is classically associated with weight loss >10% and a vicious cycle of sleepiness that in turn leads to further poor feeding. In the absence of clinical signs of dehydration, no evidence suggests that overhydration is helpful. If the infant is dehydrated, hydration should be given as clinically indicated. However, if the infant can tolerate oral feeding, oral hydration with a breast milk substitute is likely to be superior to intravenous hydration because it reduces enterohepatic circulation of bilirubin and helps wash bilirubin out of the bowel.

Leukocoria is an abnormal red reflex in which the pupil appears white. It represents various abnormalities of the visual media and is one of the primary signs of retinoblastoma. Other possible causes of leukocoria include congenital cataracts, toxocariasis, Norrie disease, retinopathy of prematurity, and Coat’s disease. Gillespie syndrome is an autosomal recessive condition characterized by congenital hypotonia, multiple ocular defects, hypoplasia of the cerebellum, and vertebral deformities. The ocular defects consist of aniridia, photophobia, reduced visual acuity, and the inability of the pupillary sphincter to contract. Leukocoria is not associated with this syndrome.

Acoustic neuroma/vestibular schwannoma is a benign slow-growing tumour. The clinical picture of the child suggests neurofibromatosis type 1 (NF1), with cafe-au-lait spots and axillary and inguinal freckling.

47,XYY syndrome is characterized by an extra copy of the Y chromosome in each of a male’s cells. Although many males with this condition are taller than average, the chromosomal change sometimes causes no unusual physical features. Most males with 47,XYY syndrome have normal production of the male sex hormone testosterone and normal sexual development, and they are usually able to father children.47,XYY syndrome is associated with an increased risk of learning disabilities and delayed development of speech and language skills. Affected boys can have delayed development of motor skills or hypotonia.Other signs and symptoms of this condition include hand tremors or other involuntary movements (motor tics), seizures, and asthma. Males with 47,XYY syndrome have an increased risk of behavioural, social, and emotional difficulties compared with their unaffected peers. These problems include attention-deficit/hyperactivity disorder (ADHD)| depression| anxiety| and autism spectrum disorder.Physical features related to 47,XYY syndrome can include increased belly fat, macrocephaly, macrodontia, flat feet (pes planus), fifth fingers that curve inward (clinodactyly), widely spaced eyes (ocular hypertelorism), and scoliosis. These characteristics vary widely among affected boys and men.

The most appropriate management would be to reassure the parents, as nasolacrimal duct dysfunction in most infants tends to resolve spontaneously.Note:Nasolacrimal duct blockage occurs in up to 5% of new-borns. 90% of these babies spontaneously resolve in the first year of life. They do not require urgent ophthalmological review, as often advice and reassurance for parents suffice for up to the age of 18 months old or so. A lump can often be seen in the nasolacrimal region following the accumulation of mucous. This does not need to be treated with antibiotics unless there are signs of acute infection.Other options:- The child does not require urgent ophthalmology review as there are no signs of severe infection. Watery eyes often lead to mucous production, which is a common non-worrying sign.- A course of topical antibiotics: Watery eyes often lead to mucous production, which is distinct from pus discharge. Unnecessary topical antibiotics can cause secondary red eyes as well as give parents false expectations for the resolution of the symptoms and signs.- A course of topical and oral antibiotics: Watery eyes often lead to mucous production, which is distinct from pus discharge. Unnecessary topical and oral antibiotics can cause secondary red eyes as well as give parents false expectations for the resolution of the symptoms and signs.- Reassurance is necessary. However, the advice that the child most likely will need a surgical procedure to resolve this is incorrect. Reassurance, but include advice that the child most likely will need a surgical procedure to resolve this is incorrect as 90% of infants that have these symptoms and signs resolve within the first year of life.

Rett syndrome is a disorder that affects the brain and occurs most commonly in girls. It presents with a period of normal development followed by severe problems with language and communication, learning, coordination, and other brain functions.

An enlarged lymph node does not necessarily need treatment especially if it is caused by a virus. If it is bacterial, antibiotics should be prescribed. Amoxicillin is first line treatment in non-penicillin allergic patients and side effects include allergic reactions like skin rash and itching

The most serious side effects of IV Lorazepam include hallucinations, agitation, confusion, amnesia and muscle weakness.

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.

Myelomeningocele is the most common type of open neural tube defect and a serious central nervous system disorder associated with significant morbidity. It is also called open spina bifida since the dura, and arachnoid matter herniates through the defect in the vertebral column. The commonest association is the decreased folate levels during early pregnancy. The alpha-fetoprotein levels are raised in the amniotic fluid. CSF leak is a common presentation with associated macrocephaly and hydrocephaly. Prenatal surgical repair is linked to a better prognosis.

Scurvy is a condition caused by a dietary deficiency of vitamin C, also known as ascorbic acid. Humans are unable to synthesize vitamin C, therefore the quantity of it that the body needs has to come from the diet. The presence of an adequate quantity of vitamin C is required for normal collagen synthesis. In scurvy bleeding tendency is due to capillary fragility and not coagulation defects, therefore blood tests are normal.

The Chi squared test is used to find the relationship between two variables, determining whether they are not independent of each other. This test of statistical significance allows you to determine the degree of confidence with which you can accept or reject the null hypothesis. The student t test compares the significant differences in data means, while rank correlation, linear regression and the correlation coefficient all help to measure the linear relationship between variables.

This patient is most likely suffering from hand, foot mouth disease which is caused by coxsackie virus A16. Its incubation period ranges from 5-7 days and only symptomatic treatment is required.

This patient might have viral meningitis as he recently suffered viral parotitis(Mumps). Microscopy and culture of the CSF would show a CSF lymphocytosis.

The normal human pancreas contains about 1,000,000 islets. The islets consist of four distinct cell types, of which three (alpha, beta, and delta cells) produce important hormones| the fourth component (C cells) has no known function.The most common islet cell, the beta cell, produces insulin.The alpha cells of the islets of Langerhans produce an opposing hormone, glucagon.The delta cells produce somatostatin, a strong inhibitor of somatotropin, insulin, and glucagon.

Treacher Collins syndrome is a congenital disorder transmitted in an autosomal dominant fashion. The basic abnormality is the TCOF 1 gene mutation, which leads to a multitude of clinical features, of which the most striking is the symmetrical craniofacial deformities. Important clinical features include conductive deafness, coloboma of lower eyelids, cleft palate, antimongoloid (short and downward slanting) palpebral fissures, deformed or absent ears, sleep apnoea, and airway issues. Hirsutism is not a recognized feature of this syndrome.

Shoulder dystocia occurs when the fetal anterior shoulder impacts against the maternal symphysis following delivery of the vertex. Less commonly, shoulder dystocia results from impaction of the posterior shoulder on the sacral promontory. Risk Factors for Shoulder DystociaMaternalAbnormal pelvic anatomyGestational diabetesPost-dates pregnancyPrevious shoulder dystociaShort statureFetalSuspected macrosomiaLabour relatedAssisted vaginal delivery (forceps or vacuum)Protracted active phase of first-stage labourProtracted second-stage labour

The drainage of cerebral spinal fluid from the third ventricle to the fourth ventricle is carried out by the cerebral aqueduct. The cerebral aqueduct is the narrowest passageway in the entire ventricular system and thus forms the most common site of blockage of flow of cerebrospinal fluid. The interventricular foramen allows passage of CSF to the third ventricle. The foramen of Luschka and Magendie are located on the fourth ventricle and allow passage of CSF to the subarachnoid space from the ventricular system. The pontine cistern is a space located on the ventral aspect of the pons. The cisterna magna is an opening on the subarachnoid space between the pia matter and the arachnoid.

Prevalence:

This is the proportion of individuals in a population who have a specific condition, disease, or attribute at a given point in time or over a specific period.

Incidence:

This is the number of new cases of a specific condition, disease, or attribute that develop in a population during a specified period of time.

Specificity:

This refers to the ability of a test to correctly identify those without the condition (true negative rate).

Sensitivity:

This refers to the ability of a test to correctly identify those with the condition (true positive rate).

Probability:

This is a measure of the likelihood that an event will occur. In the context of diseases, it can refer to the likelihood of developing a condition.

The patient is most likely suffering from obstructive jaundice. Ultrasound of the abdomen is the superior diagnostic tool in detecting and assessing biliary system obstruction, because it is easy, available, accurate and non-invasive.

The external aspect of the tympanic membrane is lined by stratified squamous epithelium. Clinical correlation: Following middle ear infections, this type of epithelium can migrate into the middle ear through a perforated tympanic membrane.The ear is composed of three anatomically distinct regions: – External ear: Auricle is composed of elastic cartilage covered by skin. The lobule has no cartilage and contains fat and fibrous tissue. External auditory meatus is variable in length, measuring approximately 2.5cm long in fully grown children. Lateral third of the external auditory meatus is cartilaginous, and the medial two-thirds is bony. The greater auricular nerve innervates the region. The auriculotemporal branch of the trigeminal nerve supplies most of the external auditory meatus and the lateral surface of the auricle. – Middle ear: It is the space between the tympanic membrane and cochlea. The aditus leads to the mastoid air cells is the route through which middle ear infections may cause mastoiditis. Anteriorly the eustachian tube connects the middle ear to the nasopharynx. The tympanic membrane consists of an outer layer of stratified squamous epithelium, a middle layer of fibrous tissue and an inner layer of mucous membrane continuous with the middle ear. The chorda tympani nerve passes on the medial side of the pars flaccida. The glossopharyngeal nerve and pain innervate the middle ear. Thus, pain may radiate to the middle ear following tonsillectomy. – Ossicles:Malleus attaches to the tympanic membrane (the Umbo). Malleus articulates with the incus (synovial joint). Incus attaches to stapes (another synovial joint). – Internal ear:It consists of the cochlea, semicircular canals, and vestibule. Organ of Corti is the sense organ of hearing and is located on the inside of the cochlear duct on the basilar membrane. Vestibule accommodates the utricle and the saccule. These structures contain endolymph and are surrounded by perilymph within the vestibule. The semicircular canals lie at various angles to the petrous temporal bone. All share a common opening into the vestibule.

Lypohypertrophy is the most common skin-related complication of insulin injection.

Due to its cholestatic properties, Flucloxacillin can block bile flow through the liver, leading to the accumulation of bilirubin in the blood, giving rise to jaundice. Dark urine is the result of excessive bilirubin in the blood being filtered by the kidney. As the bile doesn’t move into the small intestine, stools are pale.

Cushing reflex is a physiological nervous system response to increased intracranial pressure (ICP) that results in Cushing’s triad of increased blood pressure, irregular breathing, and bradycardia. It is usually seen in the terminal stages of acute head injury and may indicate imminent brain herniation. It can also be seen after the intravenous administration of epinephrine and similar drugs.

Fluid replacement therapy should be initiated immediately because the patient is suffering from severe dehydration as shown by the low urine output, the dry mucous membranes and the low skin turgor.

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.

Clotrimazole interferes with the ergosterol biosynthesis by decreasing ergosteron I biosynthesis, increasing membrane permeability, and disrupting membrane-bound enzyme systems.Vaginal candidiasis is an extremely common condition. Predisposing factors include:- diabetes mellitus- drugs: antibiotics, steroids- pregnancy- immunosuppression – iatrogenic

Advanced paternal age is associated with poor quality sperm leading to a reduction in overall fertility along with an increase in the occurrence of various medical disorders in the fetus. Advanced paternal age has been implicated as a risk factor for diseases like retinoblastoma, Marfan’s syndrome, neurofibromatosis, achondroplasia, autism spectrum disorders, schizophrenia, and acute lymphoblastic leukaemia. Down’s syndrome is mostly considered a consequence of advanced maternal age, but advanced paternal age has also been implicated as a risk factor. Turner syndrome is not found to be caused by advanced paternal age.

Fanconi anaemia, a rare autosomal recessive condition, presents with congenital abnormalities and defective hemopoiesis. Clinical signs include pallor and bruising. Hypoplasia of the thumbs and radial hypoplasia are two of the most common congenital abnormalities. Conductive deafness is also common. Those with Fanconi anaemia have a higher risk for developing acute myeloid leukaemia.

The first sign of pubarche in females is breast-bud development (thelarche).This begins between the ages of 9 and 12 years and continues to 12–18 years. Pubic hair growth occurs next (said to occur in stage 3), at ages 9–14 years, and is complete at 12–16 years. Menarche occurs relatively late in stage 4 (age 11–15 years) and is associated with a deceleration in growth. The peak height velocity is reached earlier (10–13 years) and growth is completed much earlier than in boys.