Injuries to the peroneal nerve can cause numbness, tingling, pain, weakness and foot drop. The branches of the common peroneal nerve innervate and control the muscles in the legs that lift the ankle and toes upward (dorsi flexion).

Based on the clinical scenario, the most probable diagnosis is Wilson’s disease. Elevated serum ceruloplasmin levels can confirm the diagnosis.Serum ceruloplasminWilson’s disease causes reduced binding of copper to ceruloplasmin, which is the body’s primary copper carrying protein. As a result, copper cannot be excreted into the bile. Copper, therefore, builds up in the liver, causing toxicity and is secreted into the bloodstream unbound to ceruloplasmin. This free copper is deposited around the body, especially the brain, eyes and kidneys. The genetic defect means that ceruloplasmin is not released into the bloodstream| therefore, ceruloplasmin is low in Wilson’s disease.Other options:- Microscopic evaluation of the hair is performed in Menke’s disease, which is a disease of copper absorption leading to copper deficiency. This causes kinky hair, failure to thrive and neurological symptoms (such as hypotonia).- Magnetic resonance imaging (MRI) scan of the brain: An MRI brain may show features of Wilson’s disease (especially in the basal ganglia), but it is not diagnostic.- Serum ferritin: Serum ferritin becomes high in haemochromatosis. This classically causes cirrhosis, bronzing of the skin, cardiomyopathy and diabetes.- Ultrasound scan of the abdomen: While it is useful in any case of hepatomegaly| it is not going to provide the diagnosis in this case.

Based on the presented clinical scenario, the most probable diagnosis for the patient would be testicular torsion.Rationale:The gubernaculum is the structure responsible for aiding the descent of the testicles from the abdomen into the scrotum. The processus vaginalis precedes the descent of the testes and then undergoes closure. Abnormalities such as the persistence of a patent processus vaginalis, known as bell clapper deformity, predispose to testicular torsion.Other options:- Varicocele: Nutcracker syndrome occurs where the left renal vein becomes compressed in between the superior mesenteric artery and the aorta. Since the left gonadal vein drains into the left renal vein, this results in a varicocele. – Epididymitis and mumps orchitis are differentials for acute testicular pain but are not due to a defect in the processus vaginalis. – An incarcerated inguinal hernia presents mainly with signs of bowel obstruction which are not mentioned in the clinical scenario.The descent of testes:- Until the end of foetal life, the testicles are located within the abdominal cavity. – They are initially located on the posterior abdominal wall on a level with the upper lumbar vertebrae (L2). – Attached to the inferior aspect of the testis is the gubernaculum testis which extends caudally to the inguinal region, through the canal and down to the superficial skin. – It is interesting to note that both the testis and the gubernaculum are extra-peritoneal.- As the foetus grows, the gubernaculum becomes progressively shorter. It carries the peritoneum of the anterior abdominal wall (the processus vaginalis). As the processus vaginalis descends the testis is guided by the gubernaculum down the posterior abdominal wall and the back of the processus vaginalis into the scrotum.- By the third month of foetal life the testes are located in the iliac fossae, by the seventh they lie at the level of the deep inguinal ring.Usually, the processus vaginalis closes after birth but may persist predisposing to indirect hernias. On the other hand, a partial closure may result in the development of cysts on the cord.

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.

Meckel’s diverticulum is a congenital diverticulum of the small intestine. It is a remnant of the omphalomesenteric duct (also called the vitellointestinal duct) and contains ectopic ileal, gastric or pancreatic mucosa.Rule of 2’s- occurs in 2% of the population- it is located 2 feet proximal to the ileocaecal valve- it is 2 inches long- it is 2 times more common in men- there are 2 tissue types involvedIt is typically asymptomatic. Symptomatic presentation indicates inflammation of the diverticulum. The symptoms include:- Abdominal pain mimicking appendicitis- Rectal bleeding- Intestinal obstruction: secondary to an omphalomesenteric band (most commonly), volvulus and intussusceptionManagement:Surgical removal if the neck of the diverticulum is narrow or symptomatic. Surgical options are excision or formal small bowel resection and anastomosis.

The aetiology of macrocephaly is diverse.The most common cause is benign familial macrocephaly characterized by enlargement of the subarachnoid spaces and accounts for almost 50% of cases.Other causes are:- Enlargement of skull bones – Hyperostosis cranii – associated with disorders such as osteogenesis imperfecta, achondroplasia, and osteopetrosis- Secondary enlargement due to bone marrow expansion – as seen in thalassemia major- Increase in volume of cerebrospinal fluid- Hydrocephalus, Choroid plexus papilloma, Benign familial macrocephaly- Megalencephaly – Leukodystrophies – Canavan disease, Alexander disease, megalencephalic leukoencephalopathy with subcortical cysts- Lysosomal storage disorders – Tay-Sachs, mucopolysaccharidosis, gangliosidosis- Neurocutaneous disorders – Tuberous sclerosis, Sturge-weber syndrome, neurofibromatosis, Gorlin syndrome- Autism spectrum disorder- Other syndromes – Fragile X syndrome, Cowden syndrome, Sotos syndrome- Increased intracranial pressure (ICP)- CNS infections, Pseudotumor cerebriSubdural collections including hygromas- Mass lesions and an increase in the volume of bloodTumourIntraventricular haemorrhage, subdural hematoma, arteriovenous malformation

Diabetes insipidus (DI) is defined as the passage of large volumes (>3 L/24 hr) of dilute urine (< 300 mOsm/kg). It has the following 2 major forms:Central (neurogenic, pituitary, or neurohypophyseal) DI, characterized by decreased secretion of antidiuretic hormone (ADH| also referred to as arginine vasopressin [AVP])Nephrogenic DI, characterized by decreased ability to concentrate urine because of resistance to ADH action in the kidney.The boy most probably has nephrogenic diabetes insidious (DI) not central DI so he is not responding to the ADH treatment.

Amoxicillin has high efficacy against haemophilus influenza and streptococcus pneumonia, the most common organisms of otitis media. It is an oral drug with high bioavailability.

From the given scenario, the extraocular muscle affected in the child is superior oblique muscle. Point to remember:All of the extraocular muscles are supplied by the oculomotor nerve (3rd cranial nerve), except superior oblique (trochlear nerve/4th cranial nerve) and lateral rectus (abducens nerve/6th cranial nerve).The superior oblique muscle causes the eye to move downwards and medially. The unopposed inferior oblique, in this case, causes the eye to deviate upwards and medially. Children tend to tilt their head (torticollis) to the side opposite to the affected eye with their chin down toward the shoulder, and their face turned away from the affected side to decrease the diplopia.

Haemophilia B (also known as Christmas disease) is due to a deficiency in factor IX. Haemophilia A is due to a deficiency in factor VIII.

Key Observations:

1. Cyanosis and Low Oxygen Saturation:
   • Central cyanosis indicates mixing of oxygenated and deoxygenated blood.
   • The aortic oxygen saturation is low (76%), indicating a significant amount of deoxygenated blood entering systemic circulation.
2. Pressure Analysis:
   • The right ventricle pressure is significantly elevated (110/6 mmHg), suggesting an obstructive lesion like pulmonary stenosis or an increased volume load due to a shunt.
   • The pulmonary artery pressure is low (20/5 mmHg) despite the high right ventricular pressure, suggesting an obstruction to flow from the right ventricle to the pulmonary artery, consistent with pulmonary stenosis.
3. Oxygen Saturation Analysis:
   • There is a notable drop in oxygen saturation from the left ventricle (87%) to the aorta (76%), indicating a mixture of oxygenated and deoxygenated blood in the systemic circulation, suggestive of a right-to-left shunt.

Differential Diagnosis:

1. Pulmonary Stenosis:
   • Supported by elevated right ventricular pressure and low pulmonary artery pressure.
2. Ventricular Septal Defect (VSD):
   • Would typically cause left-to-right shunting, leading to increased pulmonary blood flow and higher oxygen saturation in the right ventricle and pulmonary artery, which is not observed here.
3. Over-riding Aorta:
   • Seen in conditions like Tetralogy of Fallot where the aorta receives blood from both the right and left ventricles, leading to mixed oxygen saturation.
4. Right-to-Left Shunt:
   • The data indicates a right-to-left shunt, with low oxygen saturation in the aorta, suggesting that deoxygenated blood is bypassing the lungs and entering systemic circulation.
5. Aortic Stenosis:
   • Typically presents with high left ventricular pressure and a pressure gradient between the left ventricle and the aorta, which is not observed here.

Conclusion:

Given the data, the most likely abnormalities present in this patient are Pulmonary Stenosis, Right-to-Left Shunt, and Over-riding Aorta. These findings are consistent with a condition like Tetralogy of Fallot, where all these features are present.

Biliary atresia is a rare condition that usually becomes symptomatic 2 to 8 weeks after birth. It can be congenital or acquired. Typical symptoms include jaundice, weight loss, dark urine and pale stools.

H. pylori release the enzyme urease that has the ability to split urea releasing nitrogen. This process increases the pH in the gastric antrum making the gastric pH less acidic.Helicobacter pylori:It is a spiral, microaerophilic, gram-negative bacterium. It is one of the most common causes of antral gastritis in children. Ulcers are less common in children compared with adults| however, when they occur, they are more common in the duodenum.The presence of H.pylori can be confirmed by:- Stool antigen test (preferred)- Serology- Endoscopy with biopsy and culture- Rapid urease testsH.pylori gastritis may be associated with:- Iron deficiency anaemia- Gastric malignancy Management:The treatment is with triple therapy- two antibiotics, and an antacid.Treatment failure is often attributed to a possible worldwide increase in macrolide resistance. Interestingly, children have higher antibiotic resistance compared with adults.Note:Zollinger-Ellison syndrome (ZES) causes gastrin-secreting tumours and can present as a part of multiple endocrine neoplasia type 1 (MEN1)- an autosomal dominant disorder.

Developmental milestones at the age of 2 months are as follows:Social and Emotional:- Begins to smile at people – Can briefly calm herself (may bring hands to mouth and suck on hand)- Tries to look at the parents Language/Communication:- Coos, makes gurgling sounds – Turns head toward sounds Cognitive (learning, thinking, problem-solving):- Pays attention to faces – Begins to follow things with eyes and recognize people at a distance – Begins to act bored (cries, fussy) if an activity doesn’t changeMovement/Physical Development:- Can hold head up and begins to push up when lying on tummy – Makes smoother movements with arms and legs

This patient has pulmonary renal syndrome which is most commonly due to an ANCA positive vasculitis. The history of recurrent epistaxis makes Wegener’s granulomatosis the most probable diagnosis. Wegener’s granulomatosis, microscopic polyangiitis, and idiopathic pauci-immune necrotizing crescentic glomerulonephritis (NCGN) are strongly associated with antineutrophil cytoplasmic autoantibodies (ANCAs) directed against either proteinase 3 (anti-PR3) or myeloperoxidase (anti-MPO).

Tinea corporis is a type of dermatophytosis, caused by Trichophyton or Microsporum. The disease is highly contagious and rapidly spreads to all the areas of the body. It produces an itchy rash with a central area of clearance surrounded by raised scaly borders. Diagnosis can be made by skin examination. All other mentioned conditions do not affect the palms and soles.

Carbon monoxide is a colourless gas, which is toxic to animals. It has a high affinity for haemoglobin (around 250 times greater than oxygen). It combines with haemoglobin forming carboxyhaemoglobin, which decreases the oxygen-carrying capacity of the blood, leading to a left-shift in the oxygen-dissociation curve. CO is produced endogenously in limited amounts (0.4ml per hour), but the toxic levels are higher.

The most obvious sign of a congenital cataract in a child less than 1 year would be a strabismus/squint. A 12 month old child is unable to complain of loss of visual acuity and the child is likely to see well in one eye ruling out clumsiness. Amblyopia may also be difficult to test at this age unless it presents with the strabismus. ‘White’ red reflexes usually only present in very mature congenital cataracts.

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.

Morphea, also known as localized scleroderma, is a disorder characterized by excessive collagen deposition leading to thickening of the dermis, subcutaneous tissues, or both. Morphea is classified into circumscribed, generalized, linear, and pansclerotic subtypes according to the clinical presentation and depth of tissue involvement. Unlike systemic sclerosis, morphea lacks features such as sclerodactyly, Raynaud phenomenon, nailfold capillary changes, telangiectasias, and progressive internal organ involvement. Morphea can present with extracutaneous manifestations, including fever, lymphadenopathy, arthralgias, fatigue, central nervous system involvement, as well as laboratory abnormalities, including eosinophilia, polyclonal hypergammaglobulinemia, and positive antinuclear antibodies.

The characteristic cells in granulomatous inflammation are giant cells, formed from merging macrophages and epithelioid cells elongated with granular eosinophilic cytoplasm. Granulomatous reactions are seen in patients with tuberculosis. A tuberculous/caseating granuloma is characterised by a zone of central necrosis lined with giant multinucleated giant cells (Langhans cells) and surrounded by epithelioid cells, lymphocytes and fibroblasts. The caseous zone is present due to the damaged and dead giant cells and epithelioid cells.
Mast cells are only few in number and fibroblasts lay down collagen.
Basophils are not present.
The giant cell made up of macrophages are the most abundant cells in this inflammatory process.

The right testicular vein is a tributary of the inferior vena cava, while the left testicular vein drains into the left renal vein.Note:The testicular venous drainage begins in the septa and these veins together with those of the tunica vasculosa converge on the posterior border of the testis as the pampiniform plexus. The pampiniform plexus, in turn, drains to the testicular vein.

Oligohydramnios is a deficiency in the amniotic fluid volume, measured via ultrasound. Maternal factors associated with oligohydramnios include conditions where there is placental insufficiency such as chronic hypertension, preeclampsia or a thrombotic disorder, post-term pregnancy, premature rupture of membranes, certain chromosomal abnormalities, and obstructions of the foetal urinary tract. On the other hand conditions that are associated with polyhydramnios (excess amniotic fluid) include maternal diabetes, multiple gestations, Rh incompatibility and pulmonary abnormalities.

When a child does not hear the sound in the middle during Weber test, it means they either they have a conductive hearing loss on the side they hear the sound, or a sensorineural hearing loss on the opposite side. Rinne’s test helps distinguish between the two. In this particular case, the hearing loss is most probably conductive due to the middle ear effusion. Therefore, Weber’s test should be localised to the left and Rinne’s should be positive on the right.

Live virus vaccines include: Vaccinia (smallpox), Measles, Mumps, Rubella (MMR combined vaccine), Varicella (chickenpox), Influenza (nasal spray), Rotavirus, Zoster (shingles) and Yellow fever. Inactivated vaccines are Polio (IPV), Hepatitis A and Rabies.

Erythema nodosum (EN) is an acute, nodular, erythematous eruption that usually is limited to the extensor aspects of the lower legs. Chronic or recurrent erythema nodosum is rare but may occur.Currently, the most common cause of erythema nodosum is streptococcal infection in children and streptococcal infection and sarcoidosis in adults.The eruptive phase of erythema nodosum begins with flulike symptoms of fever and generalized aching. Arthralgia may occur and precedes the eruption or appears during the eruptive phase. Most lesions in infection-induced erythema nodosum heal within 7 weeks, but active disease may last up to 18 weeks. In contrast, 30% of idiopathic erythema nodosum cases may last more than 6 months. Febrile illness with dermatologic findings includes abrupt onset of illness with initial fever, followed by a painful rash within 1-2 days.

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.

HUS syndrome occurs mostly in children after some days of bloody diarrhoea. Damaged red blood cells also damage the kidney filtering unit and lead to sudden renal failure.

Based on the patient’s presentation, he’s probably suffering from Leiner’s diseaseLeiner’s disease is a severe generalised form of seborrhoeic dermatitis. It is also associated with recurrent diarrhoea, recurrent skin and internal infections, and failure to thrive.Seborrhoeic dermatitis is a common and self-limiting condition in childhood. Lesions affect the scalp (cradle cap), and sometimes the ear, nose, and eyebrows. It is characterised by greasy yellow or yellow-brown scales.There is an association with Malassezia, and the lesions are a reaction to this yeast, rather than caused by it.It is most common in the 6-12 month age group. Simple brushing with a soft bristle brush, use of oil or emollient, and ketoconazole 2% shampoo are all treatment options.

Juvenile myoclonic epilepsy is an epilepsy syndrome characterized by myoclonic jerks, generalized tonic-clonic seizures (GTCSs), and sometimes, absence seizures. The seizures of juvenile myoclonic epilepsy often occur when people first awaken in the morning. Seizures can be triggered by lack of sleep, extreme fatigue, stress, or alcohol consumption. Onset typically occurs around adolescence in otherwise healthy children. The causes of juvenile myoclonic epilepsy are very complex and not completely understood. Mutations in one of several genes, including the GABRA1 and the EFHC1 genes, can cause or increase susceptibility to this condition. Although patients usually require lifelong treatment with anticonvulsants, their overall prognosis is generally good.