A low serum free T4 level with a low, or normal serum TSH level would indicate secondary hypothyroidism. A normal TSH response to TRH is a rise at 20 minutes post-dose and then a fall by 60 minutes, while a normal prolactin response would be a rise at 20 minutes and then a fall by 60 minutes. A continued rise of TSH at 60 minutes implies hypothalamic damage. Secondary hypothyroidism is indicated by a low baseline TSH level, while primary hypothyroidism is demonstrated by a raised TSH.

Any blood test used to detect HIV infection must have a high degree of sensitivity (the probability that the test will be positive if the patient is infected) and specificity (the probability that the test will be negative if the patient is uninfected). Unfortunately, no antibody test is ever 100 % sensitive and specific. Therefore, if available, all positive test results should be confirmed by retesting, preferably by a different test method. HIV antibody tests usually become positive within 3 months of the individual being infected with the virus (the window period). In some individuals, the test may not be positive until 6 months or longer (considered unusual). In some countries, home testing kits are available. These tests are not very reliable, and support such as pre and post test counselling is not available.

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.

Diarrhoea is defined as having three or more loose or liquid stools per day, or as having more stools than is normal for that person. Severe diarrhoea, causing fluid loss and loss of bicarbonate, will result in marked dehydration and metabolic acidosis.

Based on the clinical scenario, the most probable diagnosis in this patient is Kallmann’s syndrome.Kallmann’s syndrome is due to isolated gonadotrophin-releasing hormone (GnRH) deficiency. It is often inherited in an X-linked recessive manner. Other options:- While Klinefelter’s syndrome is also associated with hypogonadism, the other clinical features of Klinefelter’s are not seen. – Cryptorchidism is ruled out by the presence of testes in the scrotum. – The presentation of the child is not suggestive of mumps orchitis or hyperprolactinaemia.

The general target of weight gain in the neonatal intensive care unit is to replicate the intrauterine growth in the third trimester, which equates to the daily weight gain of nearly 15 g/kg/day with infants receiving 120 kcal/kg/day

Among the given options a 2-year-old child with normal developmental milestones will be able to pull and push large wheeled toys and squat to play with toys on the floor.Other options:- Bouncing and catching a ball is learnt by the age of 5.- The ability to pedal a tricycle should be attained by 3 years of age, not 2.- A child can walk on tip-toe by 2.5 and run on tip-toe by (option D) 3 years of age, not 2.- The ability to momentarily maintain balance using one leg (option E) should be attained by 3 years.

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.

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.

The presence of anti-endomysial antibodies confirms the diagnosis of Celiac disease, which is the primary cause of illness in this patient. The sweat chloride test is performed with cystic fibrosis.

Normal QT interval in a 6 months old baby is < 0.44 seconds. A duration exceeding this value is referred to as QT interval prolongation, which is associated with some important congenital syndromes that include Brugada syndrome which is characterized by vasovagal syncope and sudden cardiac death, Jervell and Lange-Nielsen syndrome which is associated with congenital deafness, Andersen syndrome which is marked by bone deformities, and Timothy syndrome with associated heart disease and immunodeficiency. Romano-Ward syndrome is the commonest cause of congenital QT prolongation with no associated extra-cardiac manifestations. Lown-Ganong-Levine syndrome is characterized by a shortened PR interval and a normal QRS duration.

Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts which normally allow bile to drain from the gallbladder. Early cholangiographic changes can include fine or deep ulcerations of the common bile duct. As PSC progresses, segmental fibrosis develops within the bile ducts, with saccular dilatation of the normal areas between them, leading to the typical beads-on-a-string appearance seen on cholangiography. Although these strictures can be found anywhere on the biliary tree, the intrahepatic and extrahepatic bile ducts are simultaneously involved in the vast majority of cases.

The most probable diagnosis for this patient would be Crohn’s disease.Crohn’s disease:An inflammatory bowel disease which can affect any part of the bowel from the mouth to the anus. Symptoms include abdominal pain, diarrhoea, pyrexia and weight loss. Extra-intestinal manifestations include arthritis, uveitis, fatigue, anaemia and rashes including pyoderma gangrenosum and erythema nodosum.Other options:- Anorexia nervosa is an important diagnosis to consider. There are no indicators in the description that she has a fear of gaining weight or a strong desire to be thin.- Diabetic ketoacidosis is incorrect because there is no polydipsia or polyuria. A patient in DKA is more likely to present with vomiting and not diarrhoea.- Recurrent aphthous stomatitis is not a correct answer because it does not explain all of the symptoms described, only the mouth ulcers.- Ulcerative colitis (UC) is also incorrect. UC is a form of inflammatory bowel disease that causes inflammation in the colon. The main symptom is bloody stools, which is not mentioned as a feature in history.

From the midgut derives most of the small intestine as well as some parts of the large intestine, including the appendix. The appendix is at the base of caecum, up to 10cm long and mainly comprised of lymphoid tissue (Hence mesenteric adenitis may mimic appendicitis).

A 2 year old child who is developing normally should be able to point to three body parts, identify familiar objects in his environment such as a crayon or a toy and follow simple instructions.At 3 years old he should be able to copy a circle, jump up and down and name three colours.

Precocious puberty is the attainment of normal pubertal biochemical and physical features at an abnormally early age. The age cut-offs commonly used to define precocious puberty are 8 years for females and 9 years for males. Precocious puberty may be central (true) or peripheral (false) based on the aetiology. Central precocious puberty is due to the premature activation of the hypothalamic-pituitary-gonadal axis, which in turn leads to the development of secondary sexual characteristics at an earlier than usual age. The best laboratory investigation to diagnose central precocious puberty is a gonadotropin-releasing hormone stimulation test, which is regarded as the gold standard. It requires the collection of multiple blood samples at different time points to measure FSH and LH levels. If the LH levels increase to >8IU/L after stimulation with GnRH, then the diagnosis of central precocious puberty is confirmed.

Answer: The burn area is extremely painful until skin graftedThird-degree burns destroy the epidermis and dermis. Third-degree burns may also damage the underlying bones, muscles, and tendons. The burn site appears white or charred. There is no sensation in the area since the nerve endings are destroyed. These are not normally painful until after skin grafting is done since the nerve endings have been destroyed.

Osteochondromas, or osteocartilaginous exostoses, are the most common benign bone tumours, and tend to appear near the ends of long bones. The overgrowth can occur in any bone where cartilage forms bone, and they are capped by cartilage. They are most common in people between the ages of 10-20 years old.

The presenting features with the positive pregnancy test are highly suggestive of gestational diabetes mellitus.Diabetes Insipidus:It is much less common than gestational diabetes mellitus. It is characterised by the inability to concentrate urine, with marked thirst.Presenting symptoms include polydipsia (>3L daily), polyuria, nocturia, nocturnal enuresis.Physical examination may reveal features of dehydration and an enlarged bladder.Investigations include biochemical analysis for electrolytes, urine and plasma osmolality, fluid deprivation test, and cranial MRI.The main differential diagnosis is for diabetes insipidus is psychogenic polydipsia.There are three broad categories of diabetes insipidus (DI): – Central (cranial) DI: It is the most common form of diabetes insipidus.It occurs due to decreased secretion of ADH. It usually occurs due to hypothalamic disease and may show response to low-dose desmopressin.- Peripheral (nephrogenic) DI:It is characterised by the resistance of the kidney to ADH.It usually does not respond to low-dose desmopressin.- Gestational DI:It is rare and is mostly seen in teenage pregnancy.It usually presents in the third trimester and often resolves 4-6 weeks post-partum.

Relative risk is the probability of an outcome occurring in an exposed group as compared to the probability of that outcome in an unexposed group. In the scenario given, 50% of the children exposed developed the disease while only 10% of the children who were unexposed developed the disease. The relative risk was therefore 50/10=5. There is no further information about whether the study was controlled, the confidence interval, or the type of study. It therefore cannot be confirmed whether the chemical is causative and if it should be avoided.

History of recurrent infections and failure to thrive (probably due to pancreatic enzyme insufficiency) is highly suggestive of cystic fibrosis. Pseudomonas has been identified as an important respiratory pathogen in patients with cystic fibrosis.

Answer: Surgery over the next few daysInguinal hernia is a type of ventral hernia that occurs when an intra-abdominal structure, such as bowel or omentum, protrudes through a defect in the abdominal wall. Inguinal hernias do not spontaneously heal and must be surgically repaired because of the ever-present risk of incarceration. Generally, a surgical consultation should be made at the time of diagnosis, and repair (on an elective basis) should be performed very soon after the diagnosis is confirmed.The infant or child with an inguinal hernia generally presents with an obvious bulge at the internal or external ring or within the scrotum. The parents typically provide the history of a visible swelling or bulge, commonly intermittent, in the inguinoscrotal region in boys and inguinolabial region in girls. The swelling may or may not be associated with any pain or discomfort.

Hypogonadotropic hypogonadismIn Kallmann syndrome: impaired migration of GnRH cells and defective olfactory bulb → ↓ GnRH in hypothalamus → ↓ FSH and ↓ LH → ↓ testosterone and ↓ oestrogenIn hypothalamic and/or pituitary lesions: ↓ pituitary gonadotropins (↓ FSH and ↓ LH) → ↓ testosterone and ↓ oestrogen

Immunoglobulin G (IgG) glomerular immune deposits are seen more commonly in HSP compared to IgA nephropathy.The presentation of the child is highly suggestive of Henoch-Schönlein purpura (HSP). It is an IgA-mediated, autoimmune hypersensitivity vasculitis that targets the small vessels of the skin, GI tract, kidneys, and joints.It is most commonly seen in children aged 3 – 6years and is twice as common in boys than girls. Preceding viral URTI with low-grade pyrexia is common. The most common organism associated with HSP is, however, Group A streptococcal infection A.A purpuric rash is seen on the back of the legs and buttocks and can less frequently, affect the arms. Arthralgia is common (usually knees/ankles) in these patients. Abdominal pain and bloody diarrhoea may occur. And half of the children with HSP have renal involvement. Rarely, it can lead to end-stage renal failure.Treatment includes adequate hydration, occasionally steroids, and other immunosuppressants. The disease can recur in 1 in 3 children.

Recommended regimens3 NRTI (e.g., zidovudine, lamivudine, abacavir) OR2 NRTI (e.g., lamivudine + abacavir) AND1 NNRTI (e.g., efavirenz) OR1 PI (e.g., lopinavir) OR1 INI (e.g., raltegravir)

The boy suffers from balanitis xerotica obliterans (BXO) which is surgically treated with circumcision and urethral calibration. In fact, the condition is the only true medical indication for circumcision.

Foreign body aspiration (FBA) commonly occurs in children aged 1–3 years. FBA typically presents with sudden onset of coughing and choking, followed by stridor and dyspnoea. Obstruction of the larynx or trachea is a potentially life-threatening situation that causes severe respiratory distress, cyanosis, and suffocation. Most commonly, the foreign body (FB) becomes lodged in the main and intermediate bronchi| approx. 60% of FB are located in the right main bronchus due to the more vertical orientation compared to the left main bronchus. Reduced breath sounds on the one side only would not be explained by a tracheal obstruction as it would cause reduced breath sounds bilaterally and a more severe clinical picture.

DiGeorge syndrome is one of the most common microdeletion syndromes, resulting from 22q11 deletion. 10% of the cases can be inherited in an autosomal dominant fashion, while 90% are sporadic. The syndrome is characterized by a deficiency of both T and B-cell lines along with hearing loss, 20-fold increased lifetime chances of developing schizophrenia, renal abnormalities, congenital heart defects, and a borderline or low IQ. Distinctive facial features include micrognathia, long face, short philtrum, cleft palate, and small teeth.

HELLP syndrome is a complication of pregnancy characterized by haemolysis, elevated liver enzymes, and a low platelet count. It usually begins during the last three months of pregnancy or shortly after childbirth. HELLP syndrome is a life-threatening condition that can potentially complicate pregnancy. It is named for 3 features of the condition: Haemolysis, Elevated Liver enzyme levels, and Low Platelet levels. It typically occurs in the last 3 months of pregnancy (the third trimester) but can also start soon after delivery. A wide range of non-specific symptoms may be present in women with HELLP syndrome. Symptoms may include fatigue| malaise| fluid retention and excess weight gain| headache| nausea and vomiting| pain in the upper right or middle of the abdomen| blurry vision| and rarely, nosebleed or seizures. The cause of HELLP syndrome is not known, but certain risk factors have been associated with the condition. It is most common in women with preeclampsia or eclampsia. If not diagnosed and treated quickly, HELLP syndrome can lead to serious complications for the mother and baby. The main treatment is to deliver the baby as soon as possible, even if premature, if there is distress of the mother or the baby. Treatment may also include medications needed for the mother or baby, and blood transfusion for severe bleeding problems.

Renal stones < 5mm generally pass spontaneously with adequate fluid intake. Stones 5mm-10mm with pain not resolving, require medical expulsive therapy with Nifedipine or Tamsulosin. For stones larger than 10mm, ESWL or Ureteroscopy is indicated. For stones as big as 2cm, percutaneous nephrolithotomy should be applied.