The sensitivity of a screening test can be described in a variety of ways, typically such as sensitivity being the ability of a screening test to detect a true positive, being based on the true positive rate, reflecting a test’s ability to correctly identify all people who have a condition, or, if 100%, identifying all people with a condition of interest by those people testing positive on the test.The specificity of a test is defined in a variety of ways, typically such as specificity is the ability of a screening test to detect a true negative, being based on the true negative rate, correctly identifying people who do not have a condition, or, if 100%, identifying all patients who do not have the condition of interest by those people testing negative on the test.

Infections of the superficial skin around the eyes are called periorbital, or preseptal, cellulitis. It is predominantly a paediatric disease. Erysipelas is a bacterial skin infection involving the upper dermis which extends into the superficial cutaneous lymphatics. Sinusitis is in sinuses. Orbital infections and conjunctivitis are within the eye.

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.

The baby may have hydrocephalus and no surgery can be done until it is excluded.Cranial sonography is an important part of neonatal care in general, and high-risk and unstable premature infants, in particular. It allows rapid evaluation of infants in the intensive care units without the need for sedation and with virtually no risk. Expectedly, sonography represents an ideal imaging modality in neonates due to its portability, lower cost, speed, and lack of ionizing radiations. Although there are numerous indications for cranial sonography, it appears to be most useful for detection and follow-up of intracranial haemorrhage, hydrocephalus, and periventricular leukomalacia (PVL).

Answer: Spontaneous bacterial peritonitisThe presence of periorbital and facial oedema with normal blood pressure in this toddler indicates that he has nephrotic syndrome. Nephrotic syndrome can be associated with a series of complications that can affect an individual’s health and quality of life:Spontaneous bacterial peritonitis can develop where there is ascites present. This is a frequent development in children but very rarely found in adults.Spontaneous bacterial peritonitis (SBP) is the development of a bacterial infection in the peritoneum, despite the absence of an obvious source for the infection. It is specifically an infection of the ascitic fluid – an increased volume of peritoneal fluid. Ascites is most commonly a complication of cirrhosis of the liver. It can also occur in patients with nephrotic syndrome. SBP has a high mortality rate.The diagnosis of SBP requires paracentesis, a sampling of the peritoneal fluid taken from the peritoneal cavity. If the fluid contains large numbers of white blood cells known as neutrophils (>250 cells/µL), infection is confirmed and antibiotics will be given, without waiting for culture results. In addition to antibiotics, infusions of albumin are usually administered.Signs and symptoms of spontaneous bacterial peritonitis (SBP) include fevers, chills, nausea, vomiting, abdominal pain and tenderness, general malaise, altered mental status, and worsening ascites. Thirteen percent of patients have no signs or symptoms. In cases of acute or chronic liver failure SBP is one of the main triggers for hepatic encephalopathy, and where there is no other clear causal indication for this, SBP may be suspected.These symptoms can also be the same for a spontaneous fungal peritonitis (SFP) and therefore make a differentiation difficult. Delay of diagnosis can delay antifungal treatment and lead to a higher mortality rate.

Gilbert’s syndrome is an autosomal recessive condition that results from defective bilirubin conjugation due to a deficiency of UDP glucuronyl transferase – 1. The prevalence is approximately 1-2% in the general population.The clinical presentation of Gilbert’s syndrome include:- Unconjugated hyperbilinaemia- Jaundice can occur during an intercurrent illnessManagement:Blood investigations usually reveal a rise in bilirubin following prolonged fasting or intravenous nicotinic acid.No treatment required for these patients.Other options:- CYP2C9 deficiency causes reduced warfarin metabolism, and subsequent enhanced drug effects. – Pancreatic disease, cholestasis, excessive alcohol consumption and certain drugs are common causes of raised GGT levels- Defective hepatocyte excretion of conjugated bilirubin is related to the pathophysiology of Dubin-Johnson syndrome- Reduced CYP2C19 levels can lead to the disordered metabolism of clopidogrel and other drugs such as proton-pump inhibitors, anticonvulsants and sedatives.

Among the given options, the most likely cause for the patient’s presenting symptoms is acute interstitial nephritis secondary to anti-tubercular therapy (ATT)Drug-induced acute interstitial nephritis can occur following treatment with beta-lactams, sulphonamides, rifampicin, ethambutol, and erythromycin. They can cause an acute allergic reaction with the infiltration of immune cells.Acute interstitial nephritis is said to be the most common renal complication in patients undergoing anti-TB treatment. Rifampicin is the most implicated drug, although ethambutol can also be a cause. The pathogenesis involves an immune-complex mediated acute allergic response, which leads to their deposition on renal vessels, the glomerular endothelium, and the interstitial area. Other options:Isoniazid does not affect the kidneys. Pulmonary-renal syndrome is a feature of Goodpasture’s syndrome. It is characterized by renal failure and lung haemorrhage. Severe cardiac or renal failure ensues and is complicated by pulmonary oedema, systemic lupus erythematosus, Henoch-Schönlein purpura, and cryoglobulinemia.

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.

From the given clinical scenario, the peroxisomal disorder in question is Refsum’s disease.It is characterised by anosmia, early-onset retinitis pigmentosa (night blindness), chronic ataxia, variable neuropathy, deafness and ichthyosis. It is an inherited disorder of fatty acid oxidation with phytanic acid accumulation in the blood and tissues. This leads to the motor and sensory neuropathy. Other options:- Loss of sensation in extremities, dysarthria and diabetes is suggestive of Friedrich’s Ataxia. It is the most common autosomal recessive cause of ataxia. Associated features include dysarthria, scoliosis, diabetes and hypertrophic cardiomyopathy. – Numbness of the limbs, seizures and developmental delay suggests mitochondrial cytopathy such as NARP (Neuropathy, Ataxia and Retinitis Pigmentosa). Learning difficulties, developmental delays and convulsions are not uncommon, as with many mitochondrial disorders. – Rapid, chaotic eye movements, behaviour change and irritability, suggest opsoclonus-myoclonus syndrome. It is thought to be a Para infectious or paraneoplastic condition (secondary to neuroblastoma) linked to an abnormal immune response. Children present unwell with altered behaviour, irritability, ataxia, random chaotic eye movements and later myoclonus. – Sweet-smelling urine, lethargy and seizures suggest Maple Syrup Urine Disease (MSUD). It is an autosomal recessive organic acidaemia. There is a distinct sweet odour to the urine of affected individuals, particularly at times of acute illness. Without treatment, MSUD can lead to seizures, brain damage, coma and death. The most common and classic form affects babies shortly after birth, but variant forms may not be evident until later childhood.

The baby most probably has dystrophic epidermolysis bullosa, a primarily autosomal dominant disorder associated with keratin 5 and 14 defects. Initial management consists of supportive measures such as protecting the skin.

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.

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.

Based on the presentation, the child most probably is suffering from a refractive error.Astigmatism, myopia and high hypermetropia could all cause these symptoms. This child has difficulty in using vision for finer tasks such as reading. Mild to moderate refractive error would not impair the child’s ability to play or even watch television as for the child in question. Note: Refractive error is the most common treatable cause of reduced vision in children all over the world! Other options:- A congenital cataract is rare and retinal dystrophy is even rarer. – Amblyopia would suggest poor vision in only one eye, something that might not cause symptoms in this age group. – Parents or teachers would have probably noticed squint if it was present.

If a child is not saying single words with meaning by 18 months it suggests that he or she is not following normal developmental milestones and further investigation is needed. Children are usually expected to be dry by day at the age of 3 years and dry by night at the age of 4 years, however 10% of 5 year old children and 5% of 10 year old children still wet the bed.

Among the given options, Di-George syndrome is not associated with adrenal gland disorders.Di-George syndrome is characterised by distinct facial features (micrognathia, cleft palate, short philtrum, and low-set ears), hypocalcaemia, mental retardation, cardiac defects (especially tetralogy of Fallot), and immune deficiencies.A useful memory aid is CATCH-22:- Cardiac defects- Abnormal facial features- Thymic aplasia/hypoplasia- Cleft palate- Hypocalcaemia/Hypoparathyroidism- 22 – Due to 22q11 deletionOther options:- Addison’s disease is a result of adrenal hypofunction and may present with collapse secondary to a salt-losing crisis.- Congenital adrenal hyperplasia: CAH is caused by the deficiency of an enzyme (classically 21-hydroxylase deficiency) in the biosynthetic pathway in the adrenal cortex, leading to insufficient production of cortisol and aldosterone, and a build-up of 17-hydroxyprogesterone.- Cushing’s syndrome is a syndrome of cortisol excess. An adrenal tumour is a primary cause.- Pheochromocytoma is a catecholamine releasing tumour of the adrenal gland/s.

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 most important test recommended among the given options is the measurement of creatine kinase levels.The child presents with a gross motor developmental delay, and multiple investigations can be undertaken to confirm the diagnosis. However, the clinching point in the given clinical scenario is the presence of a positive Gower’s sign.Gower’s sign is an excellent screening test for muscle weakness, which is typically observed as an early clinical feature of Duchenne muscular dystrophy (DMD).Creatinine kinase measurement is an easy and rapid test to aid in the diagnosis. Early diagnosis has significant implications not only for the child but for the family, particularly for genetic counselling. DMD is an X-linked recessive disorder, with an abnormal gene at the X chromosome at the Xp21 locus. It is a progressive degenerative muscular condition where muscle fibres are replaced by fat and fibrosis (i.e., become dystrophic).

Embryologically the testes are retroperitoneal structures in the posterior abdominal wall, attached to the anterolateral abdominal wall by the gubernaculum. The gubernaculum ‘pulls’ the testes through the deep inguinal ring, inguinal canal and superficial inguinal ring and over the pelvic brim. The gubernaculum is preceded by the processus vaginalis that is derived from the peritoneum anterior to the testes. The processus vaginalis pushes the muscle and fascial layers. These eventually make up the canal and the spermatic cord, into the scrotum. The gubernaculum persists as the scrotal ligament while part of the processus vaginalis remains as a bursa-like sac i.e. the tunica vaginalis testes. The testes therefore could be caught in any one of these places along its path of descending. The testes are never in the perineum.

By the age of three months a child should become more fascinated with their hands and fingers| they can bring their hand to their mouth, open and close their hand, and shake and grab at dangling objects and toys. Their ability to roll over will come by the time the child is 6 months, at which time they will also be able to sit with support. Soon, at 8-9 months, attempts will be made to crawl and as they approach 12 months they will be able to pull on objects to stand.

The most probable diagnosis for this patient would be Kawasaki disease.Kawasaki disease:It is an acute systemic disorder of childhood that predominantly occurs in Japan (800 cases per million in children under the age of 5 years). The causative factor is not known, but mycoplasma and HIV infection may be associated in some cases. Clinical Features:The principal clinical features are fever persisting for more than five days, bilateral non-purulent conjunctival congestion, cervical lymphadenopathy, polymorphous rash, arthralgia, palmar erythema and strawberry tongue. Other options:- Diffuse cutaneous systemic sclerosis is associated with skin, renal and gut involvement. Arthralgia, morning stiffness and flexor tenosynovitis are common. – Behçet syndrome is a vasculitis of unknown aetiology that characteristically targets venules. – Felty syndrome is the association of splenomegaly and neutropenia with rheumatoid arthritis. Lymphadenopathy is common, and there is a predisposition to recurrent infections.

Answer: MittelschmerzMittelschmerz is midcycle abdominal pain due to leakage of prostaglandin-containing follicular fluid at the time of ovulation. It is self-limited, and a theoretical concern is treatment of pain with prostaglandin synthetase inhibitors, which could prevent ovulation. The pain of mittelschmerz usually occurs in the lower abdomen and pelvis, either in the middle or to one side. The pain can range from a mild twinge to severe discomfort and usually lasts from minutes to hours. In some cases, a small amount of vaginal bleeding or discharge might occur. Some women have nausea, especially if the pain is very strong.Diagnosis of pelvic pain in women can be challenging because many symptoms and signs are insensitive and nonspecific. As the first priority, urgent life-threatening conditions (e.g., ectopic pregnancy, appendicitis, ruptured ovarian cyst) and fertility-threatening conditions (e.g., pelvic inflammatory disease, ovarian torsion) must be considered. Many women never have pain at ovulation. Some women, however, have mid-cycle pain every month, and can tell by the pain that they are ovulating.As an egg develops in the ovary, it is surrounded by follicular fluid. During ovulation, the egg and the fluid, as well as some blood, are released from the ovary. While the exact cause of mittelschmerz is not known, it is believed to be caused by the normal enlargement of the egg in the ovary just before ovulation. Also, the pain could be caused by the normal bleeding that comes with ovulation.Pelvic inflammatory disease can be ruled out if the patient is not sexually active.

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

Patients with breast cancer develop clinical symptoms rather late at advanced tumour stages. Typical signs may include:Changes in breast size and/or shape| asymmetric breastsPalpable mass: typically a single, nontender, firm mass with poorly defined margins, most commonly in the upper outer quadrantSkin changes: Retractions or dimpling (due to tightening of the Cooper ligaments), Peau d’orange: skin resembling an orange peel (due to obstruction of the lymphatic channels): Redness, oedema, and pitting of the hair folliclesNipple changes: inversion, blood-tinged dischargeAxillary lymphadenopathy: firm, enlarged lymph nodes (> 1 cm in size), that are fixed to the skin or surrounding tissueIn advanced stages: ulcerations

Pierre Robin sequence is a condition present at birth, in which the infant has micrognathia, a tongue that is placed further back than normal (glossoptosis), and cleft palate. This combination of features can lead to difficulty breathing and problems with eating early in life. Pierre Robin sequence may occur isolated or be associated with a variety of other signs and symptoms (described as syndromic). The exact causes of Pierre Robin syndrome are unknown. The most common otic anomaly is otitis media, occurring 80% of the time, followed by auricular anomalies in 75% of cases. Hearing loss, mostly conductive, occurs in 60% of patients, while external auditory canal atresia occurs in only 5% of patients.

The most appropriate step in this patient would be to admit the patient for enteral rehydration via a nasogastric tube.Enteral rehydration:Oral rehydration is the most preferred way of rehydrating children. If a child is not tolerating small-frequent-feeds, then nasogastric rehydration is an underused next best step. The fluid can be run through a continuous pump so that it is better tolerated. Note:Intravenous fluids are effective but can have profound effects on the serum electrolyte balance if not monitored closely. Most children will tolerate fluids in an emergency department, but failure to take fluids orally is not an indication for intravenous therapy.

Normal cerebrospinal fluid (CSF) glucose together with lymphocytosis, an increased opening pressure and raised CSF protein are typical of a viral meningitis.

Angelman Syndrome is a genetic disorder that affects the nervous system. The features of this condition include intellectual disability, a delay in developmental milestones, and movement disorders. The features occur as a result of the deletion or mutation of the maternal copy of the UBE3A gene located on Chromosome 15q. Though individuals usually inherit one copy of this gene from each parent, only the maternal gene remains active in parts of the brain. This phenomenon is known as genetic imprinting, and is also seen in Prader-Willi syndrome.

The patient’s history points to absence seizures. Carbamazepine has been shown to aggravate generalized seizure types, especially absence seizures, because it acts directly on the ventrobasal complex of the thalamus which is critical to the neurophysiology of absence seizures.

Jaundice in a new-born on the day of delivery is most likely due to Rh incompatibility. This occurs when the mother is Rh-negative and the baby is Rh-positive. Antibodies in the mother against the Rh factor in the baby will destroy the red blood cells in the baby, increasing the bilirubin in the blood. Breast milk jaundice and Galactosemia do not occur immediately after birth, and congenital rubella syndrome and formula feeding does not cause jaundice in babies.

Omega-shaped epiglottis is a characteristic feature in the X-ray of a patient with laryngomalacia.