Group B beta-haemolytic Streptococcus (GBS) and Escherichia coli are the most common cause of early sepsis. Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is best known as a cause of postpartum infection and as the most common cause of neonatal sepsis. The GBS organism colonizes the vagina, GI tract, and the upper respiratory tract of healthy humans. GBS infection is almost always associated with underlying abnormalities. In elderly persons aged 70 years or older, GBS infection is strongly linked with congestive heart failure and being bedridden.Penicillin remains the drug of choice for group B streptococcal infection but resistance may occur.

A 10 year old child, with a history of URTI and haematuria, presents a picture consistent with a diagnosis of IgA nephropathy. This condition can present with proteinuria and generalized swelling. However, an important differentiating point from rapidly progressive GN is the duration. IgA nephropathy is usually <10 days (commonly 4-5 day history of infection).

The most probable cause for the patient’s presenting symptoms is Sarcoptes scabeii.Scabies:The boy in the scenario presents with a pruritic rash affecting the palms of the hands, especially in the web spaces between the fingers. Additionally, the fact that his sister is showing similar symptoms is an indication of its infectivity. The female Sarcoptes scabiei var hominis mite burrows into the webs of fingers and the sides of digits as seen in the child.This parasitic skin infestation presents typically with nocturnal itching. Other options:- Herpes simplex virus type 1 (HSV-1): This can affect this age group but would usually present with a vesicular perioral rash with associated erythema. – Human papillomavirus (HPV): Cutaneous human papillomavirus infection causes warts, which can form a dome and fleshy shaped lesions on the palms of the hands, but these are not usually itchy. Similar to the causative agent in the boy, they are contagious.- Poxvirus: These viruses cause molluscum contagiosum which presents as dome-shaped lesions anywhere on the body, rather than specifically in palms of hands or finger webs as seen in the boy. Poxviruses are also very infectious.- Staphylococcal infection: This causes impetigo, which presents with yellow discharge and underlying erythema. Impetigo is not usually itchy and can present on any part of the body, rather than the specific areas seen in the boy.

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.

The property described in the question is heterogeneity.Heterogeneity is when a single phenotype or genetic disorder can be caused by multiple numbers of genetic mutations.Other options:- Pleiotropy occurs when a single gene influences multiple phenotypic traits. The underlying mechanism is that the gene codes for a product that is used by various cells. A classic example of pleiotropy is the human disease PKU (phenylketonuria).- The penetrance of a disease-causing mutation is the proportion of individuals with the mutation who exhibit clinical symptoms. For example, the gene responsible for a particular autosomal dominant disorder has 70% penetrance, then 70% of those with the mutation will develop the disease, while 30% will not.

There are two lateral rotators of the arm, the infraspinatus and the teres minor muscles. The infraspinatus muscle receives nerve supply from C5 and C6 via the suprascapular nerve, whilst the teres minor is supplied by C5 via the axillary nerve.

Based on the presenting features, the patient has developed a septal haematoma after the trauma. Septal hematoma:In this condition, blood collects between the septal cartilage and the perichondrium. The patient classically presents with symptoms of nasal difficulty and pain following a nasal injury. Care should be taken not to misdiagnose a septal haematoma as a blood clot on the septum. In the case of a septal haematoma the swelling will typically be visible on both sides of the septum although this is not always the case. Referral to an ENT surgeon is indicated because, if untreated, there is a high risk of cartilage breakdown and complications related to infection.Other options:- The nosebleed has now stopped therefore compression is no longer required. The boy has developed a septal haematoma after traumatic injury. – CT head is not indicated in this patient as the diagnosis is clearly a septal hematoma.- Management of a septal hematoma consists of drainage and antibiotics. There is no role for intranasal corticosteroids.- If untreated, there is a high risk of cartilage breakdown and complications related to infection. Thus, referral to the ENT is essential| reassurance and discharge can lead to complications.

Breslow thickness is measured from the top of the granular layer of the epidermis (or, if the surface is ulcerated, from the base of the ulcer) to the deepest invasive cell across the broad base of the tumour (dermal/subcutaneous) as described by Breslow.Margins of excision-Related to Breslow thicknessLesions 0-1mm thick – 1cmLesions 1-2mm thick – 1- 2cm (Depending upon site and pathological features)Lesions 2-4mm thick – 2-3 cm (Depending upon site and pathological features)Lesions >4 mm thick – 3cmMarsden J et al Revised UK guidelines for management of Melanoma. Br J Dermatol 2010 163:238-256.

Coarctation of the aorta is one of the serious forms of congenital heart diseases characterized by a congenitally narrowed down proximal thoracic aorta. This narrowing is usually located distal to the origin of the left subclavian artery. Coarctation can occur in isolation but can accompany other cardiac lesions, including a bicuspid aortic valve. When the coarctation is located just above the left subclavian artery, raised blood pressure can be noted in the right arm. The most common type of murmur found in coarctation of the aorta is a diastolic murmur of aortic regurgitation due to the presence of a bicuspid aortic valve. Exercise augmented cardiac output is only affected in cases where coarctation of the aorta leads to heart failure. Hypertension persists even after the surgical repair and needs to be closely monitored.

Alpha-fetoprotein (AFP) is a plasma protein produced by the embryonic yolk sac and the fetal liver. AFP levels in serum, amniotic fluid, and urine functions as a screening test for congenital disabilities, chromosomal abnormalities, as well as some other adult occurring tumours and pathologies.Pregnant maternal serum AFP levels are elevated in:- Neural tube defects (e.g., spina bifida, anencephaly)- Omphalocele- Gastroschisis- posterior urethral valves- nephrosis- GI obstruction- teratomas

Severe cyanotic heart diseases such as pulmonary stenosis, transposition of the great vessels, hypoplastic left heart syndrome and truncus arteriosus all run the risk of a poor prognosis for a neonate. To continue the supply of oxygen the ductus arteriosus must be kept patent. This can be done with the immediate administration of Prostaglandin E1 as a temporary measure until a surgical intervention such as an atrial septostomy can be done. The closure of the duct can subsequently be initiated with the administration of indomethacin and oxygen.

Total parenteral nutrition (TPN) frequently causes derangement of liver function in children. Other options:- While line sepsis and thromboembolism are recognised complications of TPN, they do not occur frequently. – A child who is on TPN will require regular blood tests because of the potential for the development of electrolyte abnormalities. Need to observe their liver function, in order to provide TPN more accurately.

ADH primarily acts on the collecting ducts.Other options:- The juxtaglomerular apparatus is the site of renin production.- The proximal tubule conducts isosmotic reabsorption of about 60% of sodium chloride and volume. Most of the glucose, amino acids, potassium and phosphate are absorbed here.- The loop of Henle is the site of 25% of sodium reabsorption. Active Chloride transport provides the basis for the counter current multiplier aiding urinary concentration.- The distal convoluted tubule is impermeable to water and acts via active sodium chloride absorption to dilute urine.

Among the options provided, an 8-week-old full-term infant with normal developmental milestones will smile in response to appropriate stimuli.Rationale:Smiles in response to appropriate stimuli are seen from around 6 weeks of age. A social smile, where the infant has an awareness that a smile attracts attention, is not observed until around 3 months of age.Other options:- At 6 weeks an infant is able to follow objects in the horizontal plane through 90 deg| fixing and following an object through 180 deg in the horizontal plane is a milestone achieved at 3 months, as is pushing up onto forearms. – Pushing up onto hands occurs by around 5 months.- Infants of 3 months should startle to a 60 dB sound.

The equation, lung function = 3.2 + (1.7 x height) is linear, but this does not necessarily mean that the relationship itself is linear. The equation is able to predict that taller individuals are more likely to have greater lung functions. No information is given on whether the coefficients and the R value are statistically significant.

After birth, the infant takes its first breath and is exposed to a myriad of stimuli. The pulmonary vessels dilate, and pulmonary vascular resistance (PVR) decreases remarkably while the systemic vascular pressure rises above the PVR. This allows blood from the right ventricle to enter the lungs for oxygenation. In most cases, this increased oxygenation, along with other factors, causes the ductal wall to constrict and the ductus arteriosus to close functionally. As left-sided pressures rise higher than right-sided pressures, the foramen ovale functionally closes. With the clamping of the umbilical cord and the cessation of blood flow, pressures in the portal sinus decrease. This causes the muscle in the sinus wall near the ductus venosus to contract. The lumen of the duct becomes filled with connective tissue, and, in two months, the ductus venosus becomes a fibrous strand embedded in the wall of the liver, thus establishing adult circulation.

The most probable diagnosis in this patient would be hyphaema.The acuity has varied because the blood has been settling in the anterior chamber of the eye, thus allowing a reasonable level of visual acuity. The size of the tennis ball (which is not as harmful as a squash ball in the eye) and the fact that it was struck from a distance would cause a moderately significant injury due to pressure to the globe. Other options:- The absence of severe pain makes a large corneal abrasion less likely. – Vitreous haemorrhage would lead to very poor acuity, more likely ‘hand movements only’. – A retinal detachment or traumatic cataract would not produce such immediate symptoms, and if they did occur it would probably be in the presence of more extensive eye trauma and pain, with additional signs of both hyphaema and vitreous haemorrhage.

Becker’s muscular dystrophy is a disease characterised by progressive weakness and wasting of the skeletal and cardiac muscles. It is inherited and primarily affects males.

The most probable diagnosis for this patient would be torsion of a hydatid cyst of the testis.Note:The differential diagnoses in acute testicular pain/swelling are listed in the possible answers. Testicular torsion typically affects adolescent males and presents with acute painful swelling and a horizontally lying testicle. Other options:- Epididymo-orchitis is diagnosed during surgery when a thickened erythematous epididymis is noted. Ectopic ureteric insertion into the vas must be excluded by ultrasound scan on an out-patient basis. The hydatid cyst or cyst of Morgagni represents the remnants of the Mullerian structure. In the pre-pubertal child, a surge in hormones can stimulate growth and chance of torsion. It is diagnosed by surgical exploration or by a blue dot sign. Idiopathic scrotal oedema tends to be within the scrotum itself, and the testis can be examined in the groin to exclude pain in the testis. All acute scrotal pain must be explored to exclude testicular torsion unless a surgical registrar is convinced of a torted hydatid cyst.- An 8-year-old is more likely to present with a torted hydatid cyst. The blue dot sign is diagnostic and can negate the need for surgical exploration. The age of the child also makes epididymo-orchitis less likely.- Idiopathic scrotal oedema presents with an erythematous and thickened scrotum. This can cross the midline and involve the whole scrotum.- Finally, an inguinal hernia would present with a mass in the groin extending to the scrotum that you cannot get above.

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.

Children are able to use a palmar grasp by the age of 6 months and use a pincer grasp by the age of 9 to 10 months. They can sit with support by 6 months and sit without support by 7 to 9 months. They can vocalize by 3 months. Stranger fear appears from 7 to 10 months. So this baby’s development is normal.

DiGeorge syndrome usually presents at a young age with abnormal faces. Chest x-ray is characterised by an absent thymic shadow and recurrent infections due to an abnormal T-cell mediated immune response. Sometimes it presents by convulsions of the new-born due to hypocalcaemia as a result of a malfunctioning parathyroid gland and low levels of PTH.

Intussusception is the invagination of one segment of the intestine within a more distal segment. It presents with vomiting, abdominal pain, and a palpable abdominal mass.Intussusception usually affects infants between 6-18 months old. Boys are affected twice as often as girls

The rational part of a teen’s brain isn’t fully developed until the age of 25 or so.In fact, recent research has found that adult and teen brains work differently. Adults think with the prefrontal cortex, the brain’s rational part. This is the part of the brain that responds to situations with good judgment and an awareness of long-term consequences. Teens process information with the amygdala. This is the emotional part.

Answer: Acute Epstein Barr virus infectionThe Epstein–Barr virus is one of eight known human herpesvirus types in the herpes family, and is one of the most common viruses in humans. Infection with Epstein-Barr virus (EBV) is common and usually occurs in childhood or early adulthood.EBV is the cause of infectious mononucleosis, an illness associated with symptoms and signs like:fever,fatigue,swollen tonsils,headache, andsweats,sore throat,swollen lymph nodes in the neck, andsometimes an enlarged spleen.Although EBV can cause mononucleosis, not everyone infected with the virus will get mononucleosis. White blood cells called B cells are the primary targets of EBV infection.Petechiae on the palate are characteristic of streptococcal pharyngitis but also can be seen in Epstein–Barr virus infection, Arcanobacterium haemolyticum pharyngitis, rubella, roseola, viral haemorrhagic fevers, thrombocytopenia, and palatal trauma.

A teratoma is a tumour containing tissue elements that are similar to normal derivatives of more than one germ layer. They usually contain skin, hair, teeth and bone tissue and are more common in children, behaving as a benign tumour. After puberty, they are regarded as malignant and can metastasise.

Recurrent bacterial infections may be due to lack of B-cell function, consequently resulting in a lack of gamma globulins production. Once the maternal antibodies have depleted, the disease manifests with greater severity and is called x-linked agammaglobulinemia also known as ‘X-linked hypogammaglobulinemia’, ‘XLA’ or ‘Bruton-type agammaglobulinemia. it is a rare x linked genetic disorder that compromises the bodies ability to fight infections.
Acute leukaemia causes immunodeficiency but not so specific.
DiGeorge syndrome is due to lack of T cell function.
Aplastic anaemia and EBV infection does not cause immunodeficiency.

Cystic fibrosis has an autosomal recessive pattern of inheritance, meaning that a person might be a carrier of the disease without developing it. If the unaffected partner is a carrier, then there is a 50% chance of inheritance and a 50% chance of having a child who is a carrier. However, if the partner is not a carrier, the offspring will not develop the disease but the possibility of being a carrier raises up to 100%.

Tay-Sachs disease is an autosomal recessive disease. For the brother to present with the disease, both parents must be carriers. Therefore, with each pregnancy the probability that the child would be affected is 1 in 4| the probability that the child would be a carrier is 2 in 4| and the probability that the child would be unaffected is also 1 in 4. Unaffected children have a 2 in 3 chance, or 66%, of becoming a carrier according to the patterns of autosomal recessive inheritance.

The accuracy of the test for calcium levels in the blood is affected by the blood level of albumin. If albumin levels are low, the calcium level can also appear low.This is termed as pseudohypocalcemia.Hypocalcaemia usually presents with muscle spams. These can include spasms of voluntary muscle but also smooth muscle such as in the airways (causing bronchospasm) and in the heart (causing angina).