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.

The child most likely has nephritic syndrome which is characterised by a reduced renal function, proteinuria of non-nephrotic range, haematuria, erythrocyte casts, and oedema. Polyarteritis nodosa usually occurs in middle-aged men but can also be seen in young children. It is accompanied by severe systemic manifestations such as fever, malaise, weight loss and myalgia.Renal cell carcinoma usually presents around 55 years with the classic triad of haematuria, loin pain and a unilateral mass in the flank.Polycystic kidney disease usually presents in adult life with acute loin pain and palpation of masses in the flanks.

Polycythaemia is a commonly occurring neonatal disorder, which is characterized by a venous haematocrit ≥ 65%. It increases the blood viscosity and causes microcirculatory flow impairment in the end-organs. Causes of polycythaemia are multi-factorial, but the significant risk factors are maternal diabetes, SGA, LGA or post-term birth, infants with chromosomal abnormalities, and delayed clamping of the cord. Jaundice is not a recognized risk factor for polycythaemia.

Neurofibromatosis (aka Von Recklinghausen’s disease) includes: neurofibrosarcomas, pheochromocytoma, optic nerve tumours, scoliosis and acoustic neuromas.

The most probable cause for chronic parotitis in this patient would be HIV infection.Rationale:Chronic infectious parotitis is relatively uncommon in children. While mycobacterial infection can result in chronic parotitis, HIV is a relatively more common cause. The presentation should always prompt an HIV test. Other options:- While mumps is the most common cause of acute viral parotitis, the chronic nature of the boy’s presentation rules it out. – Acute bacterial parotitis is usually unilateral and is warm and tender to touch.

Developmental dysplasia (DDH) of the hip refers to patients who are born with a dislocated or unstable hip due to abnormal development of the hip. Female infants and first born infants are most likely to present with DDH. Other risk factors for DDH include, breech positioning, oligohydramnios, high birth weight or post date babies.

The most likely cause of microcephaly in an asymptomatic 3-year-old child is congenital rubella syndrome.Microcephaly is defined as head circumference > two standard deviations below the mean.The causes of microcephaly include:- Genetic disorders: Down syndrome, Edward syndrome, Patau syndrome, Williams syndrome, Angelman syndrome, and Rett syndrome.- Infective: Meningitis, toxoplasmosis, CMV, rubella, varicella, HIVand Zika.- Acquired causes: Severe brain malformations, neurodegenerative diseases, hypoxic-ischemic injury, infarction, antenatal exposure to drugs, alcohol, and other toxins. Severe malnutrition and uncontrolled phenylketonuria in the mother are other causes of microcephaly in children.- Craniosynostosis- Neurometabolic disorders- Early non-accidental trauma- Fanconi anaemia- Other causes include: Familial and nonfamilial nonsyndromic microcephalyMost children with microcephaly have one or several associated symptoms:- Developmental delay- Seizures- Visual abnormalities- Short stature

Based on the presentation, the developmental age of the child is 8 months.The primitive reflexes are indicators of functional integrity and maturity. The majority of reflexes do not persist beyond 6 months of age. There are 13 reflexes of importance, including:- Moro reflex- Startle reflex- Rooting reflex- Sucking reflex- Grasp reflex- Voluntary palmar grasp reflex- Voluntary reach reflex- Stepping reflex- Asymmetrical tonic neck reflex (ATNR)- Parachute reflex- Plantar reflex- Tendon reflex- ClonusIt is interesting to note that gastrocolic reflex is not a primitive reflex.Ninety-five per cent of reflexes will have disappeared by the ages shown below:- 6 weeks: Stepping- 3-4 months: Palmar grasp and Moro- 6 months: Sucking, rooting, and asymmetrical tonic neck reflex (ATNR)

To quantify differences between percentages you can use Fisher’s exact test.Odds ratios, relative risks and number needed to treat are ways of quantifying differences between percentages in two groups, however are not in themselves significance tests.

Not uncommonly, children insert a foreign body in their ear canal and do not mention it to their parents. If any pain accompanies purulent drainage, the possibility of a foreign body in the ear canal should be considered. A patient with a foreign body in place will not improve until it is removedOrganic foreign bodies tend to elicit inflammatory reactions. In the ear, they predispose to otitis externa, suppurative otitis media and hearing loss

The spinal muscular atrophies (SMAs) comprise a group of autosomal recessive disorders characterized by progressive weakness of the lower motor neurons. several types of spinal muscular atrophies have been described based on age when accompanying clinical features appear. The most common types are acute infantile (SMA type I, or Werdnig-Hoffman disease), chronic infantile (SMA type II), chronic juvenile (SMA type III or Kugelberg-Welander disease), and adult-onset (SMA type IV) forms.SMA type I – Acute infantile or Werdnig-Hoffman diseasePatients present before 6 months of age, with 95% of patients having signs and symptoms by 3 months. They have severe, progressive muscle weakness and flaccid or reduced muscle tone (hypotonia). Bulbar dysfunction includes poor suck ability, reduced swallowing, and respiratory failure. Patients have no involvement of the extraocular muscles, and facial weakness is often minimal or absent. They have no evidence of cerebral involvement, and infants appear alert.Reports of impaired fetal movements are observed in 30% of cases, and 60% of infants with SMA type I are floppy babies at birth. Prolonged cyanosis may be noted at delivery. In some instances, the disease can cause fulminant weakness in the first few days of life. Such severe weakness and early bulbar dysfunction are associated with short life expectancy, with a mean survival of 5.9 months. In 95% of cases, infants die from complications of the disease by 18 months.

Physiological jaundice is the condition in which there is a yellow discolouration of the eyes and the skin of the baby caused by the build up of bilirubin in the blood due to an immature liver. No other symptoms accompany physiological jaundice, thus it will not present with difficulty in feeding. All the other conditions listed can present with feeding problems.

The patient history suggests a spontaneous tension pneumothorax which is a life-threatening situation in which excess air is introduced into the pleural space surrounding the lung. When there is a significant amount of air trapped in the pleural cavity, the increasing pressure from this abnormal air causes the lung to shrink and collapse, leading to respiratory distress. This pressure also pushes the mediastinum (including the heart and great vessels) away from its central position, e.g. deviated trachea, and diminishing the cardiac output. Tension pneumothoraxes cause chest pain, extreme shortness of breath, respiratory failure, hypoxia, tachycardia, and hypotension. These are definitively managed by insertion of a chest tube. However, in the emergency setting temporizing measures are needed while chest tube materials are being gathered. In these situations, urgent needle thoracostomy (also called needle decompression) is performed.

Vaccines should not be given to a feverish child.

The risk of ischemic stroke in patients using combined oral contraceptives is increased in patients with additional stroke risk factors, including smoking, hypertension, and migraine with aura.

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.

Liddle’s syndrome,  is an autosomal dominant disorder, that is characterized by early, and frequently severe, high blood pressure associated with low plasma renin activity, metabolic alkalosis, low blood potassium, and normal to low levels of aldosterone. Liddle syndrome involves abnormal kidney function, with excess reabsorption of sodium and loss of potassium from the renal tubule. Bartter Syndrome also presents with hypokalaemia, however blood pressure of these patients is usually low or normal.

Hematopoietic stem cells (HSCs) are a rare population of cells residing in the bone marrow (BM) and continuously replenish all mature blood cells throughout their life span.

Somogyi effect presents with night-time hypoglycaemia followed by early-morning hyperglycaemia, hence the glycosuria.

Mumps presents with a prodromal phase of general malaise and fever. On examination there is usually painful parotid swelling which has high chances of becoming bilateral. In OM with effusion there are no signs of infection and the only symptom is usually hearing loss. Acute otitis externa produces otalgia as well as ear discharge and itching. Acute OM produces otalgia and specific findings upon otoscopy. In acute mastoiditis the patient experiences ear discharge, otalgia, headache, hearing loss and other general signs of inflammation.