The central nervous system comprises of two types of cells| neurons and neuroglial cells. Glial cells are the support cells that serve a number of important functions. Three types of neuroglia comprise the mature nervous system, which are ependymal cells, microglia, and macroglia. The macroglia are of two types oligodendrocytes and astrocytes. Microglia are the neuroglial cells that serve the function of phagocytosis since they are derived from the hematopoietic stem cells and share properties with tissue macrophages. They remove the cellular debris from the site of injury or normal cellular turnover by performing scavenger function.

Von Hippel-Lindau syndrome is a genetic disorder inherited in autosomal dominant fashion. It is caused by the mutations of the VHL gene located on chromosome 3. The syndrome is characterized by the creation of multiple benign and malignant tumours involving various bodily systems along with the formation of numerous visceral cysts, including the renal and epididymal cysts. Down’s syndrome is associated with renal cysts, but it does not follow the autosomal dominant mode of inheritance, rather it is caused by non-disjunction of chromosome 21 during meiosis. Exomphalos is a defect of the medial abdominal wall leading to abnormal protrusion of abdominal viscera through it. It is not associated with renal cysts. Turner’s syndrome may be associated with renal cysts formation, but it is not transmitted in an autosomal dominant fashion. Polycystic kidney disease of childhood follows an autosomal recessive pattern of transmission.

The post-ingestion plasma level, which is required in order to guide the treatment, reaches a peak at 4 hours. Levels requiring antidote (N-acetyl cysteine) include: 100 mcg per ml at 4 hours, 35 mcg per ml at 10 hours and 25 mcg per ml at 12 hours. These levels are in conjunction with the levels recorded and they should all be put down on a treatment nomogram.

The differentiation between type 1 and type 2 epithelia in the developing lung buds is evident from 16-24 weeks of gestation.Development of the respiratory tract has five stages:- Embryonic (at 4 – 5 weeks of gestation):Formation of lung buds, trachea and mainstem bronchi occur. These structures are formed from a ventral outpouching of foregut pharynx. At this stage, the beginnings of the five lung lobes are present.- Pseudoglandular (at 5 – 16 weeks of gestation):Formation of terminal bronchioles, cartilage and smooth muscles occur in this stage. – Canalicular (at 16-24 weeks gestation): Differentiation of type I and II epithelial cells can be done in this stage. There is also an increase in the size of proximal airways).- Saccular (at 24 – 40 weeks of gestation): Terminal saccule formation occurs. Production of surfactant takes place at this stage with an increase in the number of goblet cellsUp to half the adult number of alveoli are in place by this stage.- Alveolar (occurs between 32 weeks of gestation till the post-natal age 8): Formation of alveoli and septation occurs with the expansion of air spaces.

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.

Mature human breast milk is nutrient and enzyme rich, optimal for human infants. The average calorie requirement for a one month old infant is about 100kcal/kg/day. Lactose, the most abundant carbohydrate, is beneficial for the baby’s developing gastro intestinal system. The proteins in mature milk are mostly whey (as compared to a high proportion of casein in cows milk), which digests easily. Other proteins found in breast milk include immunoglobulin, lysozyme, lactoferrin and lactalbumin. In terms of micronutrients, while Vitamin K levels are low in breast milk, Vitamin A, C and E are found in higher concentrations than in cow’s milk.

The submandibular glands provide the bulk of salivary secretions contributing close to 70%. The sublingual glands provide 5% and the remainder from the parotid.

The likely diagnosis in this case is Haemolytic Uremic Syndrome (HUS), which is generally seen in young children presenting with a triad of symptoms, namely: acute renal failure, microangiopathic haemolytic anaemia, and thrombocytopenia. The typical cause of HUS is ingestion of a strain of Escherichia coli. The laboratory results will usually include fragmented RBCs, decreased serum haptoglobin, reduced platelet count, nonspecific WBC changes, and normal coagulation tests (PTT included).

Certain infections and medications cause characteristic skin lesions, which are the result of hypersensitivity reactions to these agents. A skin rash characterized by the eruption of macules, papules, and target-like circular lesions is referred to as erythema multiforme. The target or iris lesions appear rounded with a red centre surrounded by a pale ring, which in turn is surrounded by a dark red outer ring. These are acute and self-limiting with a propensity for distal extremities. The most common infectious cause is the infection with herpes simplex virus 1 and 2 to a lesser extent. Other notable infectious causes of erythema multiforme include Mycoplasma pneumoniae, cytomegalovirus, HIV, hepatitis c virus, varicella zoster virus, adenovirus, and some fungal infections. Norovirus infection has not been implicated in the aetiology of erythema multiforme.

This clinical picture is typical of chickenpox, which is treated with antihistamines and calamine lotion. In the case of fever, acetaminophen can be used. Generally treatment is purely for symptomatic relief.

The Glasgow Coma Scale, being inappropriate for use in children (especially below the age of 5) as they are unable to elicit the verbal response as per the adult GCS. Therefore, GCS for the paediatric age group was modified to Adelaide coma scale (ACS), which is stated as follows:Best Eye Response (as in adult scale):Spontaneous – 4To speech – 3To pain – 2No response – 1Best Verbal Response:Oriented – 5Words – 4Vocal sounds – 3Cries – 2No response – 1Best Motor Response (as in adult scale):Obeys commands – 5Localises pain – 4Flexion to pain – 3 Extension to pain – 2No response – 1 The described child scores:Eye response – 1| Verbal response – 3| Motor response – 4Thus, bringing the total ACS score to 8.

Malabsorption of fat-soluble vitamins is likely in most people with Cystic Fibrosis (CF).Factors that may contribute to fat-soluble vitamin deficiencies in CF include:- Fat maldigestion and malabsorption as a consequence of pancreatic insufficiency and bile salt deficiency.- Fat maldigestion and malabsorption due to suboptimal PERT or poor adherence to PERT especially with vitamin replacement therapy.- Poor dietary intake due to anorexia or poor dietary sources of vitamins.- Poor adherence to prescribed fat-soluble vitamin supplementation.- Inappropriate vitamin supplementation regimens.- Increased utilisation and reduced bioavailability.- Short gut syndrome due to previous bowel resection.- CF-related liver disease.- Chronic antibiotic use.Vitamin A is a fat-soluble vitamin that plays a role in the eye (dark adaptation), skin, respiratory and immune systems. Vitamin A deficiency may cause night blindness and can proceed to xerophthalmia in CF.Severe vitamin D deficiency causes rickets in children and Osteomalacia in adults.Vitamin E acts as an antioxidant reducing the effects of free radicals produced by infection and chronic inflammation, thus helping to protect cell membranes from oxidative damage.Vitamin E deficiency has been associated with haemolytic anaemia in infants and may cause ataxia, neuromuscular degeneration and compromised cognitive function. Oxidative stress is enhanced in CF due to chronic respiratory inflammation.Vitamin K is important for blood coagulation and bone health.

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%.

Stridor is a sign of upper airway obstruction. One of the most common causes of stridor in children is laryngomalacia. In the absence of laryngomalacia, stridor presenting with respiratory distress, few chest signs and no preceding coryza symptoms or fever all point to the inhalation of a foreign object. This is common in children, with a peak incidence between 1 and 2 years of age. This child did not present with a high temperature, usually indicative of epiglottitis . The incidence of epiglottis has decreased due to the H. Influenza type b vaccine. Additionally viral croup and bronchiolitis present with upper respiratory tract infection. Asthma rarely presents with stridor but is rather associated with a wheeze.

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.

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.

Bernard- Soulier Syndrome results from a deficiency of platelet glycoprotein protein Ib, which mediates the initial interaction of platelets with the subendothelial components via the von Willebrand protein. It is a rare but severe bleeding disorder. Platelets do not aggregate to ristocetin. The platelet count is low, but, characteristically, the platelets are large, often the size of red blood cells, and may be missed on complete blood counts because most automatic counters do not count them as platelets.

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.

The most probable diagnosis for this patient’s symptoms is psoriasis. Psoriasis:Chronic plaque psoriasis is characterised by pinkish-red hyperkeratotic plaques, which occur mainly on extensor surfaces such as knees and elbows. The lower back, ears and scalp can also be involved. Koebner phenomenon: Psoriasis typically exhibits this phenomenon where new plaques of psoriasis occur particularly at sites of skin trauma. Diagnosis:Skin biopsy of psoriatic plaques reveals acanthosis and parakeratosis, reflecting increased skin turnover. Capillary dilatation within the dermis also occurs, surrounded by a mixed neutrophilic and lymphohistiocytic perivascular infiltrate.

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%.

Neurofibromatosis Type 1 (also known as von Recklinghausen disease) does not present with cataracts.The eye findings in NF1 are Lisch’s nodules, which are pigmentary lesions seen on the iris and constitute one of the major diagnostic features in this condition. Note:Interestingly, in another syndrome closely related to it, Neurofibromatosis type 2 (NF-2), cataracts can occur. Early detection in family members may be made by finding lens opacities (both congenital polar cataracts and posterior lenticular opacities). Other options:- Incontinentia pigmenti is an X-linked dominant disorder with pigmentary skin changes, mental retardation and eye involvement in 40% of cases. – Myotonic dystrophy is a triplet-repeat disorder with neurological symptoms and cataracts. – Lowe syndrome (oculo-cerebro-renal syndrome) is an X-linked recessive condition. Males with this X-linked recessive condition have cataracts, hypotonia, mental retardation, generalised aminoaciduria and renal tubular acidosis with hypophosphatemia. – Wilson disease is an inborn error of copper metabolism. The clinical features include hepatic involvement, progressive neurological features, eye involvement, including Kayser–Fleischer rings and cataracts.

Alopecia areata is seen in 6-8.8% of patients with Down syndrome, but only 0.1% of patients with alopecia areata have Down syndrome. The high frequency of alopecia areata in patients with Down syndrome suggests that a genetic linkage for alopecia areata may exist on chromosome 21.

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.

The endocardial cushions in the heart are the mesenchymal tissue that make up the part of the atrioventricular valves, atrial septum and ventricular septum. An incomplete fusion of these mesenchymal cells can cause an atrioventricular septal defect. The terms endocardial cushion defect, atrioventricular septal defect and common atrioventricular canal defect can be used interchangeably with one another.

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 symptoms of excessive salivation and diarrhoea, along with hypotension, bradycardia, and bronchoconstriction, indicates excess parasympathetic nervous system activity. The patient is showing features of acetylcholine toxicity. Pesticides typically contain organophosphates that are potent inhibitors of acetylcholinesterase. This enzyme is responsible for the metabolism of acetylcholine. Acetylcholine is the neurotransmitter used in the neuromuscular junction, as well as at select points in the autonomic nervous system. The autonomic acetylcholine receptors can be nicotinic (more sensitive to nicotine) or muscarinic (more sensitive to muscarine). The most relevant receptors in this scenario are the muscarinic receptors as the majority are located in the parasympathetic nervous system smooth muscle, exocrine glands, and cardiac conduction system.Other options:- Accordingly, to cause the symptoms described, there must be an abundance of acetylcholine which stimulates the muscarinic receptors to enhance the parasympathetic effects. Therefore the reduction in the formation of acetylcholine option must be incorrect as this would produce the opposite effect. – Noradrenaline is the primary neurotransmitter in the sympathetic nervous system, and both answer options relating to noradrenaline would increase the neurotransmitter and potentiate the sympathetic nervous system effects, making them incorrect.Features can predict the accumulation of acetylcholine (mnemonic = SLUD):- Salivation- Lacrimation- Urination- Defecation/diarrhoeaCardiovascular symptoms include hypotension and bradycardia. The patient can show associated small pupils and muscle fasciculationManagement:- Atropine- The role of pralidoxime is still unclear – meta-analyses to date have failed to show any clear benefit.

Although all of the options may lead to an acute red scrotum, torsion of the hydatid of Morgagni is the most common cause at this age (age 12-16 years).

The presentation of the patient and the characteristic ring-like (Bull’s eye) rash are highly suggestive of a diagnosis of Lyme disease caused by Borrelia burgdorferi. The spirochete is transmitted by Ixodid ticks. The initial presentation of this infection includes an erythema migrans rash that starts from the site of tick bite and gradually expands. Other features supporting the diagnosis are the history of camping, fever, joint pain, and the neurological symptoms presenting as facial nerve palsy.

People with Gilbert syndrome have a build-up of unconjugated bilirubin in their blood (unconjugated hyperbilirubinemia). In affected individuals, bilirubin levels fluctuate and very rarely increase to levels that cause jaundice. Gilbert syndrome is usually recognized in adolescence. If people with this condition have episodes of hyperbilirubinemia, these episodes are generally mild and typically occur when the body is under stress, for instance because of dehydration, prolonged periods without food (fasting), illness, vigorous exercise, or menstruation. Some people with Gilbert syndrome also experience abdominal discomfort or tiredness. However, approximately 30 percent of people with Gilbert syndrome have no signs or symptoms of the condition and are discovered only when routine blood tests reveal elevated unconjugated bilirubin levels.

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.