Dead space refers to inhaled air that does not take part in gas exchange. Because of this dead space, taking deep breaths slowly is more effective for gas exchange than taking quick, shallow breaths where a large proportion is dead space. Use of a snorkel by a diver increases the dead space marginally. Anatomical dead space refers to the gas in conducting areas such as mouth and trachea, and is roughly 150 ml (2.2 ml/kg body weight). This corresponds to a third of the tidal volume (400-500 ml). It can be measured by Fowler’s method, a nitrogen wash-out technique. It is posture-dependent and increases with increase in tidal volume. Physiological dead space is equal to the anatomical dead space plus the alveolar dead space, where alveolar dead space is the area in the alveoli where no effective exchange takes place due to poor blood flow in capillaries. This physiological dead space is very small normally (< 5 ml) but can increase in lung diseases. Physiological dead space can be measured by Bohr’s method. Total ventilation per minute (minute ventilation) is given by the product of tidal volume and the breathing rate. Here, the total ventilation is 600 ml times 12 breaths/min = 7200 ml/min. The problem mentions alveolar ventilation to be 6000 ml/min. Thus, the difference between the alveolar ventilation and total ventilation is 7200 – 6000 ml/min = 1200 ml/min, or 100 ml per breath at 12 breaths per min. This 100 ml is the dead space volume.

In children, more common causes of Urinary tract obstruction include the following:
UPJ or UVJ obstruction
Ectopic ureter
Ureterocoele
Megaureter
Posterior urethral valves

Posterior urethral valves:

During the early stages of embryogenesis, the most caudal end of the wolffian duct is absorbed into the primitive cloaca at the site of the future verumontanum in the posterior urethra. In healthy males, the remnants of this process are the posterior urethral folds, called plicae colliculi. Histologic studies suggest that PUVs are formed at approximately 4 weeks’ gestation, as the wolffian duct fuses with the developing cloaca.
Congenital obstructing posterior urethral membrane (COPUM) was first proposed by Dewan and Goh and was later supported by histologic studies by Baskin. This concept proposes that instead of a true valve, a persistent oblique membrane is ruptured by initial catheter placement and, secondary to rupture, forms a valve like configuration.
Indicators of possible PUVs later in childhood include the following:
Urinary tract infection (UTI)
Diurnal enuresis in boys older than 5 years
Secondary diurnal enuresis
Voiding pain or dysfunction
Abnormal urinary stream

Bacterial meningitis (including meningococcal meningitis, Haemophilus influenzae meningitis, and staphylococcal meningitis) is a neurologic emergency that is associated with significant morbidity and mortality. Initiation of empiric antibacterial therapy is therefore essential for better outcomes. The patient appears to be suffering from meningitis caused by Staphylococcus aureus. Methicillin would be the drug of choice . It is bactericidal and unlike streptomycin and chloramphenicol it is not associated with toxicity

Dukes staging and 5 year survival:
Dukes A – Tumour confined to the bowel but not extending beyond it, without nodal metastasis (95%)
Dukes B – Tumour invading bowel wall, but without nodal metastasis (75%)
Dukes C – Lymph node metastases (50%)
Dukes D – Distant metastases (6%)

Hemianopia or hemianopsia, is the loss of vision of half of the eye or loss of half the visual field. Homonymous hemianopia is the loss of vision or blindness on half of the same side of both eyes (visual field) – either both lefts of the eyes or both rights of the eyes. This condition is mainly caused by cerebrovascular accidents like a stroke that affects the optic radiation.

Answer: Flail chest injury

Flail chest is a life-threatening medical condition that occurs when a segment of the rib cage breaks due to trauma and becomes detached from the rest of the chest wall. Two of the symptoms of flail chest are chest pain and shortness of breath.

It occurs when multiple adjacent ribs are broken in multiple places, separating a segment, so a part of the chest wall moves independently. The number of ribs that must be broken varies by differing definitions: some sources say at least two adjacent ribs are broken in at least two places, some require three or more ribs in two or more places. The flail segment moves in the opposite direction to the rest of the chest wall: because of the ambient pressure in comparison to the pressure inside the lungs, it goes in while the rest of the chest is moving out, and vice versa. This so-called paradoxical breathing is painful and increases the work involved in breathing.

Flail chest is usually accompanied by a pulmonary contusion, a bruise of the lung tissue that can interfere with blood oxygenation. Often, it is the contusion, not the flail segment, that is the main cause of respiratory problems in people with both injuries.

Surgery to fix the fractures appears to result in better outcomes.

Scleroderma is a connective tissue disorder that ranges in severity and progression. The disease could show generalised skin thickening with rapid, fatal, visceral involvement; or only cutaneous involvement (typically fingers and face). The slow progressive form is also known as ‘limited cutaneous scleroderma’ or CREST syndrome (calcinosis cutis, Raynaud’s phenomenon, (o)oesophageal dysmotility, sclerodactyly, and telangiectasia).

Unlike other cancers for which a biopsy is performed, when testicular cancer is suspected the entire testicle is removed in a procedure called an orchiectomy through an incision in the groin and pulling the testicle up from the scrotum. A biopsy through the scrotum for testicular cancer runs the risk of spreading the cancer, and can complicate future treatment options. Removing the entire testicle out of the scrotum is the only safe way to diagnose for testicular cancer. Only the cancer-containing testicle is removed, and it is important to do so promptly.
If there is any uncertainty, the urologists can examine the testicle by pulling the testicle out of the scrotum; if a condition other than testis cancer is found, the testicle is placed back into the scrotum.

Testicular cancer is the most common malignancy in men aged 20-30 years. Around 95% of cases of testicular cancer are germ-cell tumours.

Surgical resection is the principal therapy for gastric cancer, as it offers the only potential for cure. A subtotal gastrectomy is usually performed for tumours of the distal stomach. Subtotal gastrectomy is the treatment of choice for middle and distal-third gastric cancer as it provides similar survival rates and better functional outcome compared to total gastrectomy, especially in early-stage disease with favourable prognosis. D2 dissections are recommended by the National Comprehensive Cancer Network over D1 dissections. A pancreas-and spleen-preserving D2 lymphadenectomy is suggested, as it provides greater staging information, and may provide a survival benefit while avoiding its excess morbidity when possible. Patients that undergo D2 lymphadenectomy as a standard part of surgical resection of gastric adenocarcinoma generally have better stage-for-stage overall survival figures compared to patients undergoing less extensive lymphadenectomies.
After partial gastrectomy, some patients report disorders such as reflux esophagitis and alkaline gastritis, as well as dumping syndrome, delayed gastric emptying and malabsorption, which are defined as functional dyspepsia. Duodenogastric reflux is recognized to be a major cause of clinical symptoms after resection.
Roux-Y reconstruction seems to be effective in reducing bile reflux into the stomach, compared to Billroth I and II procedure, and conversion to this procedure has been reported in patients with symptomatic uncontrolled reflux disease.

Atrial fibrillation is one of the most common cardiac arrhythmias. It is often asymptomatic but may present with symptoms of palpitations, fainting, chest pain and heart failure. Characteristic findings are: absence of P-waves, unorganised electrical activity in their place, irregularity of RR interval due to irregular conduction of impulses to the ventricles and if paroxysmal AF is suspected, episodes may be documented with the use of Holter monitoring

Referred pain is felt at a point away from the source of the pain or the unpleasant sensation. It arises when a nerve is damaged or compressed at a point but the pain is felt at another site that is the territory of that nerve. Common abdominal causes of referred pain to the shoulder and the shoulder blade are the liver, duodenum and gall bladder.

The flattened appearance of the face is a classical description of the dish-face deformity associated with Le Fort III fracture of the midface.

The term Le Fort fractures is applied to transverse fractures of the midface involving the maxillary bone and surrounding structures in either a horizontal, pyramidal, or transverse direction. There are three grades of Le Fort fractures:

1. Le Fort I
It is the horizontal fracture of the maxilla. Violent force over a more extensive area above the level of the
teeth will result in this type of fracture. Horizontal fracture line is seen above the apices of the maxillary teeth, detaching the tooth-bearing portion of the maxilla from the rest of the facial skeleton. Floating maxilla and Guerin’s sign is seen in such patients.

2. Le Fort II
It is a pyramidal or subzygomatic fracture. Violent force in the central region extending from glabella to the alveolus results in this type of fracture, resulting in ballooning or moon-face facial deformity.

3. Le Fort III
It is a high-level transverse or suprazygomatic fracture associated with craniofacial disjunction. The entire facial skeleton moves as a single block as a result of the trauma. The patient develops a characteristic panda facies and dish-face deformity.

Mesothelioma is a rare, aggressive form of cancer that develops in the lining of the lungs, abdomen or heart. It is linked to inhalation of asbestos commonly used in ship building and the insulation industry. It has no known cure and has a very poor prognosis.

Acute bacterial endocarditis is a fulminant illness lasting over days to weeks (<2weeks). It is most likely due to Staphylococcus aureus especially in intravenous drug abusers.

Tyrosine is the precursor to adrenaline, noradrenaline and dopamine. Tyrosine hydroxylase converts tyrosine to DOPA, which is in turn converted to dopamine, then to noradrenaline and finally adrenaline.

Bronchogenic cysts, although relatively rare, represent the most common cystic lesion of the mediastinum.
Bronchogenic cysts are the result of anomalous development of the ventral foregut; they are usually single but may be multiple and can be filled with fluid or mucus. They have been found all along the tracheoesophageal course, in perihilar or intraparenchymal sites, with a predilection for the area around the carina. Those in the mediastinum frequently attach to but do not communicate with the tracheobronchial tree. Bronchogenic cysts have also been described in more remote locations, including the interatrial septum, neck, abdomen, and retroperitoneal space.
With the advent of improved antenatal diagnosis, many infants are identified before the development of symptoms:
Chest pain and dysphagia are the most common symptoms in adults with bronchogenic cysts.
Recurrent infections may be the clinical presentation in some children
In infants, symptoms are most often produced as a result of airway or oesophageal compression.

Oesophageal duplication cysts are rare inherited lesions usually diagnosed in early childhood. Most of them are found in the mediastinum and manifest themselves as separate masses along or in continuity with the native oesophagus

Increased alkaline phosphatase is indicative of cholestasis, with a 4x or greater increase seen 1-2 days after biliary obstruction. Its level can remain elevated several days after the obstruction is resolved due to the long half life (7 days). Increase up to three times the normal level can be seen in hepatitis, cirrhosis, space-occupying lesions and infiltrative disorders. Raised alkaline phosphatase with other liver function tests being normal can occur in focal hepatic lesions like abscesses or tumours, or in partial/intermittent biliary obstruction. However, alkaline phosphatase has several isoenzymes, which originate in different organs, particularly bone. An isolated rise can also be seen in malignancies (bronchogenic carcinoma, Hodgkin’s lymphoma), post-fatty meals (from the small intestine), in pregnancy (from the placenta), in growing children (from bone growth) and in chronic renal failure (from intestine and bone). One can differentiate between hepatic and non-hepatic cause by measurement of enzymes specific to the liver e.g. gamma-glutamyl transferase (GGT).
In an elderly, asymptomatic patient, isolated rise of alkaline phosphatase usually points to bone disease (like Paget’s disease). Presence of other symptoms such as jaundice, pale stools, weight loss suggests obstructive jaundice, most probably due to pancreatic carcinoma.

In the stomach and around the duodenum, there are many arterial anastomoses. Ligation of the gastroduodenal artery would result in the retrograde flow of blood from the left gastroepiploic artery to the right gastroepiploic artery. The blood flows into the right gastroepiploic artery, a branch of the gastroduodenal artery from the left gastroepiploic artery that branches from the splenic artery. This retrograde blood flow is aimed at providing alternate blood flow to the greater curvature of the stomach.

Intraductal papilloma is the most common cause of blood-stained nipple discharge in young females.

An intraductal papilloma is a benign breast condition that develops in one or more of the milk ducts in the
breast. It is usually close to the nipple, but can
sometimes be found elsewhere in the breast. It most commonly occurs in women between ages 35–55 and generally does not increase the risk of developing breast cancer. There are no known risk factors for intraductal papilloma.

Signs and symptoms include:
1. Small lump or a discharge of
clear or blood-stained fluid from the nipple
2. Discomfort or pain around the area (usually not painful)

Diagnosis can be made by:
1. Breast examination
2. Mammogram
3. Ultrasound scan
4. Core biopsy
5. Fine needle aspiration

Women under the age of 40 are more likely to have an
ultrasound scan than a mammogram. The breast tissue in such patients can be dense which can
make the X-ray image in a mammogram less clear.
However, some women under 40 may still have
a mammogram.

Intraductal papillomas are often removed using
surgery. The surgical options include:
1. Excision biopsy
2. Vacuum assisted excision biopsy

If nipple discharge continues, then further surgical options are explored:
1. Microdochectomy (removal of the affected duct or ducts)
2. Total duct excision (removal of all the major ducts)

Gastric acid secretion is stimulated by three factors:
– Acetylcholine, from parasympathetic neurones of the vagus nerve that innervate parietal cells directly
– Gastrin, produced by pyloric G-cells
– Histamine, produced by mast cells.
Gastric acid is inhibited by three factors:
– Somatostatin
– Secretin
– Cholecystokinin

Skin, fibular collateral ligament, popliteus muscle tendon and lateral meniscus is the correct order of structures covering the lateral aspect of the knee joint from a superficial to deep.

Chemotherapy is offered to patients to help downstage advanced lesions to facilitate breast conserving surgery i.e. in grade 3 tumours with axillary node metastasis.

Pulmonary embolism is caused by the sudden blockage of a major lung blood vessel, usually by a blood clot. Symptoms include sudden sharp chest pain, cough, dyspnoea, palpitations, tachycardia or loss of consciousness. Risk factors for developing pulmonary embolism include long periods of inactivity, surgery, trauma, pregnancy, oral contraceptives, oestrogen replacement, malignancies and venous stasis.

Answer: Escharotomy

Escharotomy is the surgical division of the nonviable eschar, which allows the cutaneous envelope to become more compliant. Hence, the underlying tissues have an increased available volume to expand into, preventing further tissue injury or functional compromise.

Full-thickness circumferential and near-circumferential skin burns result in the formation of a tough, inelastic mass of burnt tissue (eschar). The eschar, by virtue of this inelasticity, results in the burn-induced compartment syndrome. This is caused by the accumulation of extracellular and extravascular fluid within confined anatomic spaces of the extremities or digits. The excessive fluid causes the intracompartmental pressures to increase, resulting in collapse of the contained vascular and lymphatic structures and, hence, loss of tissue viability. The capillary closure pressure of 30 mm Hg, also measured as the compartment pressure, is accepted as that which requires intervention to prevent tissue death.

The circumferential eschar over the torso can lead to significant compromise of chest wall excursions and can hinder ventilation. Abdominal compartment syndrome with visceral hypoperfusion is associated with severe burns of the abdomen and torso. (A literature review by Strang et al found the prevalence of abdominal compartment syndrome in severely burned patients to be 4.1-16.6%, with the mean mortality rate for this condition in these patients to be 74.8%). Similarly, airway patency and venous return may be compromised by circumferential burns involving the neck.

Performing an escharotomy will therefore improve ventilation.

The median nerve provides cutaneous innervation to the skin of the palmar radial three and a half fingers. Also the site of injury indicates that the medial nerve may have been injured as it passes into the hand by crossing over the anterior wrist.

Parkinson’s disease is a degenerative, movement disorder of the central nervous system, and is typically characterized by muscle rigidity, tremor and bradykinesia (in extreme cases, akinesia). Secondary symptoms include high-level cognitive dysfunction and subtle language problems.
Parkinson’s disease is also called ‘primary Parkinsonism’ or ‘idiopathic Parkinson’s disease and is the most common cause of Parkinsonism, a group of similar symptoms. The disorder is caused due to loss of pigmented dopaminergic cells in the pars compacta region of the substantia nigra.

Open haemorrhoidectomy is traditionally viewed as a painful procedure. Most operations are performed under general or regional anaesthesia. Following excisional haemorrhoidectomy, severe pain is not unusual, a well placed caudal anaesthetic will counter this. A pudendal nerve block is an alternative but is less effective than a caudal.

Answer: Waterhouse- Friderichsen syndrome

Waterhouse-Friderichsen syndrome is a condition characterized by the abrupt onset of fever, petechiae, arthralgia, weakness, and myalgias, followed by acute haemorrhagic necrosis of the adrenal glands and severe cardiovascular dysfunction. The syndrome is most often associated with meningococcal septicaemia but may occur as a complication of sepsis caused by other organisms, including certain streptococcal species. This disorder may be associated with a history of splenectomy.

Fulminant infection from meningococcal bacteria in the bloodstream is a medical emergency and requires emergent treatment with vasopressors, fluid resuscitation, and appropriate antibiotics. Benzylpenicillin was once the drug of choice with chloramphenicol as a good alternative in allergic patients. Ceftriaxone is an antibiotic commonly employed today. Hydrocortisone can sometimes reverse the adrenal insufficiency. Amputations, reconstructive surgery, and tissue grafting are sometimes needed as a result of tissue necrosis (typically of the extremities) caused by the infection.

The spleen, left kidney, stomach, the splenic flexure of the colon and the suprarenal glands are all in the same quadrant- the left upper quadrant. However, the spleen is the most readily injured organ when there is fracture to the 10th, 11th and the 12th ribs because of its close association with these ribs. This patient exhibits a great indication of a ruptured spleen (tenderness on the left mid and posterior axillary line). The spleen is a thin capsulated organ with a spongy parenchyma, allowing it to bleed profusely in the event of injury. The liver, head of the pancreas and the duodenum are all in the right upper quadrant.

Branches that stem from the abdominal aorta can be divided into three: the visceral branches, parietal branches and terminal branches. Of the visceral branches, the suprarenal, renal, testicular and ovarian arteries are paired while the coeliac artery and superior and inferior mesenteric arteries are unpaired. Of the parietal branches the inferior phrenic and lumbar arteries are paired while the middle sacral artery is unpaired. The terminal branches i.e. the common iliac arteries are paired.

Around 1% of calcium in the body is available for buffering changes in calcium ion balance. These are mainly derived from the bone that are freely exchangeable with extracellular fluid.

A reactivated tuberculosis with granuloma formation is characteristic of type IV reaction. It is also called a delayed type of hypersensitivity reaction and takes around 2-8 days to deliver. It is a cell mediated response with the involvement of CD8 and CD4 cells and the release of IL-1 from macrophages that further activate these CD cells.
Granulomatous reactions are mostly cell-mediated.
Type I reactions are allergic and anaphylactic reactions and type II are complement-mediated immune reactions.

Hypernatremia, characterised by a high serum sodium concentration, is rarely associated with volume overload (hypervolemia). A hypovolaemic hypernatremia may be seen during excessive administration of hypertonic sodium bicarbonate, hypertonic saline or hyperalimentation.

Answer: Bochdalek hernia

A Bochdalek hernia is one of two forms of a congenital diaphragmatic hernia, the other form being Morgagni hernia. A Bochdalek hernia is a congenital abnormality in which an opening exists in the infant’s diaphragm, allowing normally intra-abdominal organs (particularly the stomach and intestines) to protrude into the thoracic cavity. In the majority of patients, the affected lung will be deformed, and the resulting lung compression can be life-threatening. Bochdalek hernias occur more commonly on the posterior left side (85%, versus right side 15%).

In normal Bochdalek hernia cases, the symptoms are often observable simultaneously with the baby’s birth. A few of the symptoms of a Bochdalek Hernia include difficulty breathing, fast respiration and increased heart rate. Also, if the baby appears to have cyanosis (blue-tinted skin) this can also be a sign. Another way to differentiate a healthy baby from a baby with Bochdalek Hernia, is to look at the chest immediately after birth. If the baby has a Bochdalek Hernia it may appear that one side of the chest cavity is larger than the other and or the abdomen seems to be scaphoid (caved in).

Situs inversus (also called situs transversus or oppositus) is a congenital condition in which the major visceral organs are reversed or mirrored from their normal positions. The normal arrangement of internal organs is known as situs solitus while situs inversus is generally the mirror image of situs solitus. Although cardiac problems are more common than in the general population, most people with situs inversus have no medical symptoms or complications resulting from the condition, and until the advent of modern medicine it was usually undiagnosed. In the absence of congenital heart defects, individuals with situs inversus are homeostatically normal, and can live standard healthy lives, without any complications related to their medical condition. There is a 5–10% prevalence of congenital heart disease in individuals with situs inversus totalis, most commonly transposition of the great vessels. The incidence of congenital heart disease is 95% in situs inversus with levocardia.

Cystic fibrosis is a progressive, genetic disease that causes persistent lung infections and limits the ability to breathe over time. In people with CF, mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause the CFTR protein to become dysfunctional. When the protein is not working correctly, it’s unable to help move chloride — a component of salt — to the cell surface. Without the chloride to attract water to the cell surface, the mucus in various organs becomes thick and sticky. In the lungs, the mucus clogs the airways and traps germs, like bacteria, leading to infections, inflammation, respiratory failure, and other complications.

Necrotizing enterocolitis (NEC) is a medical condition where a portion of the bowel dies. It typically occurs in new-borns that are either premature or otherwise unwell. Symptoms may include poor feeding, bloating, decreased activity, blood in the stool, or vomiting of bile.
The exact cause is unclear. Risk factors include congenital heart disease, birth asphyxia, exchange transfusion, and premature rupture of membranes. The underlying mechanism is believed to involve a combination of poor blood flow and infection of the intestines. Diagnosis is based on symptoms and confirmed with medical imaging.

Morgagni hernias are one of the congenital diaphragmatic hernias (CDH), and is characterized by herniation through the foramen of Morgagni. When compared to Bochdalek hernias, Morgagni hernias are:
-anterior
-more often right-sided (,90%)
-small
-rare (,2% of CDH)
-at low risk of prolapse

Only ,30% of patients are symptomatic. New-borns may present with respiratory distress at birth similar to a Bochdalek hernia. Additionally, recurrent chest infections and gastrointestinal symptoms have been reported in those with previously undiagnosed Morgagni hernia.
The image of the transverse colon is herniated into the thoracic cavity, through a mid line defect and this indicates that it is a Morgagni hernia since the foramen of a Morgagni hernia occurs in the anterior midline through the sternocostal hiatus of the diaphragm, with 90% of cases occurring on the right side.

Clinical manifestations of congenital diaphragmatic hernia (CDH) include the following:

Early diagnosis – Right-side heart; decreased breath sounds on the affected side; scaphoid abdomen; bowel sounds in the thorax, respiratory distress, and/or cyanosis on auscultation; CDH can often be diagnosed in utero with ultrasonography (US), magnetic resonance imaging (MRI), or both
Late diagnosis – Chest mass on chest radiography, gastric volvulus, splenic volvulus, or large-bowel obstruction
Congenital hernias (neonatal onset) – Respiratory distress and/or cyanosis occurs within the first 24 hours of life; CDH may not be diagnosed for several years if the defect is small enough that it does not cause significant pulmonary dysfunction
Congenital hernias (childhood or adult onset) – Obstructive symptoms from protrusion of the colon, chest pain, tightness or fullness the in chest, sepsis following strangulation or perforation, and many respiratory symptoms occur.

Baroreceptors are sensors located in the blood vessels of all vertebrate animals. They sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained. Acute dehydration results in decreased plasma volume and increased plasma osmolarity, since more water than salt is lost in sweat. The decrease in plasma volume leads to an inhibition of the baroreceptors and a lower firing rate. The increase in plasma osmolarity leads to increased ADH secretion and high plasma ADH levels, which increases water permeability of collecting duct cells. Therefore more water is reabsorbed by the kidneys and renal water excretion is low.

To determine compliance of the respiratory system, changes in transmural pressures (in and out) immediately across the lung or chest cage (or both) are measured simultaneously with changes in lung or thoracic cavity volume. Changes in lung or thoracic cage volume are determined using a spirometer with transmural pressures measured by pressure transducers. For the lung alone, transmural pressure is calculated as the difference between alveolar (pA; inside) and intrapleural (ppl; outside) pressure. To calculate chest cage compliance, transmural pressure is ppl (inside) minus atmospheric pressure (pB; outside). For the combined lung–chest cage, transmural pressure or transpulmonary pressure is computed as pA – pB. pA pressure is determined by having the subject deeply inhale a measured volume of air from a spirometer. Under physiological conditions the transpulmonary or recoil pressure is always positive; intrapleural pressure is always negative and relatively large, while alveolar pressure moves from slightly negative to slightly positive as a person breathes.

The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is an indicator for measuring the efficacy of both the intrinsic and common coagulation pathway. Prolonged aPTT may indicate: use of heparin, antiphospholipid antibody and coagulation factor deficiency (e.g., haemophilia). Deficiencies of factors VIII, IX, XI and XII and rarely von Willebrand factor (if causing a low factor VIII level) may lead to a prolonged aPTT correcting on mixing studies.

Infection by Ascaris lumbricoides usually occurs after individuals have visited places like sub-Saharan Africa or the Far East. Unlike Ancylostoma duodenale infection, there is usually an evidence of both worms and eggs in the stool. The absence of pruritus makes Enterobius vermicularis less likely.

Ascariasis occurs due to infection with a roundworm Ascaris lumbricoides. It begins in the gut following ingestion, then penetrates the duodenal wall to migrate to the lungs, is coughed up and swallowed, and the cycle begins again.

Diagnosis is made by identification of worms or eggs within the faeces. Treatment is with mebendazole.

The sympathetic nervous system regulates vascular tone, dilation of pupils, arrector pili muscles, sweat production and visceral reflexes. Neurones that supply the voluntary muscles originate from the ventral horn of the spinal cord. If these nerves were thus damaged, these functions would be impaired. The sympathetic nervous system is not responsible for voluntary muscle activity.

The lumber triangle is bound medially by the border of the latissimus dorsi, laterally by the external abdominal oblique and by the iliac crest inferiorly. This is exactly where the hernia that is described is located.

Tuberous sclerosis is a genetic disorder characterized by the growth of numerous noncancerous (benign) tumours in many parts of the body. These tumours can occur in the skin, brain, kidneys, and other organs, in some cases leading to significant health problems. Tuberous sclerosis also causes developmental problems, and the signs and symptoms of the condition vary from person to person.

Virtually all affected people have skin abnormalities, including patches of unusually light-coloured skin, areas of raised and thickened skin, and growths under the nails. Tumours on the face called facial angiofibromas are also common beginning in childhood.

Tuberous sclerosis often affects the brain, causing seizures, behavioural problems such as hyperactivity and aggression, and intellectual disability or learning problems. Some affected children have the characteristic features of autism, a developmental disorder that affects communication and social interaction. Benign brain tumours can also develop and these tumours can cause serious or life-threatening complications.

Kidney tumours are common in people with tuberous sclerosis; these growths can cause severe problems with kidney function and may be life-threatening in some cases. Additionally, tumours can develop in the heart, lungs, and the retina.

The first rib articulates with the sternum right below the sternoclavicular joint.
The sternal angle articulates with the costal cartilage of the second rib.
The nipple is found between the fourth and the fifth ribs, in the fourth intercostal space.
The xiphoid process is located right below the point of articulation of the costal cartilage of rib 7 with the sternum.
The root of the lung is the part of the lung where neurovascular structures enter and leave the lung.
Acromioclavicular joint is the point of articulation between the acromion process and the clavicle, near the shoulder.

A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature and solid tissues. Dermoid cysts grow slowly and this type of cystic teratoma is nearly always benign.

This is a case of Brown-Sequard syndrome.

Brown-Sequard syndrome is caused by hemisection of the spinal cord following stab injuries or lateral vertebral fractures. It results in ipsilateral paralysis (pyramidal tract), and also loss of proprioception and fine discrimination(dorsal columns). Pain and temperature sensations are lost on the contralateral side. This is because the fibres of the spinothalamic tract have decussated below the level of the cord transection.

Lesions bearing normal dermal appendages and regular borders are likely to be benign pigmented naevi. Therefore diagnostic and not radical excision is indicated. Incision biopsy should not be done.

Melanocytic naevi are pigmented moles. Some moles are present at birth or appear within the first two years of life. These are known as congenital melanocytic naevi. Most develop during childhood and early adult life and are, consequently, called acquired melanocytic naevi. The number of moles increase up to the age of 30–40. Thereafter, the number of naevi tend to decrease. New moles appearing in adulthood need to be monitored and checked if growing or changing. Moles can be found anywhere on the skin, including on the hands and feet, genitals, eyes, and scalp.

There are three main types of acquired melanocytic naevi:
1. Junctional melanocytic naevi: flat and usually circular.
2. Compound melanocytic naevi: raised brown bumps most of which are hairy, some have a slightly warty surface.
3. Intradermal melanocytic naevi: raised and often hairy bumps, similar to compound naevi but more pale coloured (often skin-coloured).

The posterior relations of the head of the pancreas include: the inferior vena cava, the common bile duct, the renal veins, the right crus of the diaphragm and the aorta.

The dorsal primary ramus of the spinal nerve C2 is the greater occipital nerve which provides cutaneous innervation to the skin of the back of the head. The ventral primary ramus gives off the great auricular nerve, the lesser occipital nerve and the ansa cervicalis.

The complications of central vein catheterization (CVC) include infection, thrombosis, occlusion, and, in particular, mechanical complications which usually occur during insertion and are closely related to the anatomic location of the central veins. Infectious complications are reported to occur in 5% to 26% of patients, mechanical complications in 5% to 19%, and thrombotic complications in 2% to 26%. Mechanical complications associated with the insertion of central lines include arterial puncture, hematoma, haemothorax, pneumothorax, arterial-venous fistula, venous air embolism, nerve injury, thoracic duct injury (left side only), intraluminal dissection, and puncture of the aorta
Pneumothorax is one of the most common CVC insertion complications, reportedly representing up to 30% of all mechanical adverse events of CVC insertion.
Clinician-performed bedside US allows the diagnosis of pneumothorax to be made immediately, with a high degree of sensitivity and with better accuracy than supine chest films and equal to that of CT scan.
Tension pneumothorax is classically characterized by hypotension and hypoxia. On examination, breath sounds are absent on the affected haemothorax and the trachea deviates away from the affected side. The thorax may also be hyper resonant; jugular venous distention and tachycardia may be present.
If a pneumothorax is diagnosed the treatment strategy should be determined by the following factors: (I) size; (II) symptoms; (III) spontaneous breathing or use of mechanical ventilation; (IV) clinical diagnosis of a tension pneumothorax.

Treatment consisted of: (I) observation; (II) outpatient insertion of a Heimlich valve; (III) inpatient tube thoracostomy.

Brucellosis is a highly contagious zoonosis caused by ingestion of unpasteurized milk or undercooked meat from infected animals, or close contact with their secretions.

Carcinoid tumours are of neuroendocrine origin and derived from primitive stem cells in the gut wall, especially the appendix.
Signs and symptoms of carcinoid tumours vary greatly. Carcinoid tumours can be non-functioning presenting as a tumour mass or functioning. The sign and symptoms of a non-functioning tumour depend on the tumour location and size as well as on the presence of metastases. Therefore, findings range from no tumour-related symptoms (most carcinoid tumours) to full symptoms of carcinoid syndrome (primarily in adults).
– Periodic abdominal pain: Most common presentation for a small intestinal carcinoid; often associated with malignant carcinoid syndrome
– Cutaneous flushing: Early and frequent (94%) symptom
– Diarrhoea and malabsorption (84%)
– Cardiac manifestations (60%): Valvular heart lesions, fibrosis of the endocardium; may lead to heart failure with tachycardia and hypertension
– Wheezing or asthma-like syndrome (25%)
– Pellagra
– Carcinoid crisis can be the most serious symptom of carcinoid tumours and can be life-threatening. It can occur suddenly, after stress, or following chemotherapy and anaesthesia.

Two surgical procedures can be applied to treat appendiceal Neuroendocrine Neoplasm (NEN): simple appendicectomy and oncological right-sided hemicolectomy.
– For T1 (ENETS) or T1a (UICC/AJCC) NEN (i.e. <1 cm), generally simple appendicectomy is curative and sufficient.
– For NEN >2 cm with a T3 stage (ENETS) or higher and T2 (UICC/AJCC) or higher respectively, a right-sided hemicolectomy is advised due to the increased risk of lymph node metastasis and long-term tumour recurrence and/or distant metastasis. The right-sided hemico- lectomy should be performed either as the initial surgical intervention should the problem be overt at that time, or during a second intervention.

Situated at the upper part of the thorax beneath the pectoralis major, is a thin pectoralis minor, triangular muscle. It originates from the third, fourth and fifth ribs, near the cartilage and from the aponeurosis which covers the intercostals. These fibres move upwards and laterally to join and form a flat tendon. This is inserted into the medial border and upper surface of the coracoid process of the scapula. Through this medial anterior thoracic nerve, fibres from the pectoralis minor are received from the eighth cervical and first thoracic nerves. This pectoralis minor pushes down on the point of the shoulder (glenoid fossa), drawing the scapula downward and medially towards the thorax which throws the inferior angle backwards.

Painful, bright red rectal bleeding is usually due to a fissure. Presence of pain and the sentinel tag suggests a posterior fissure-in-ano.

Anal fissures are a common cause of painful, bright red, rectal bleeding. Most fissures are idiopathic and present as a painful mucocutaneous defect in the posterior midline (90% cases). Fissures are more likely to be anteriorly located in females, particularly if they are multiparous. Diseases associated with fissure-in-ano include:
1. Crohn’s disease
2. Tuberculosis
3. Internal rectal prolapse

Diagnosis:
In most cases, the defect can be visualised as a posterior midline epithelial defect. Where symptoms are highly suggestive of the condition and examination findings are unclear, an examination under anaesthesia may be helpful. Atypical disease presentation should be investigated with colonoscopy and EUA with biopsies of the area.

Treatment:
1. Stool softeners are important as hard stools may tear the epithelium and result in recurrent symptoms. The most effective first-line agents are topically applied GTN (0.2%) or Diltiazem (2%) paste. Side effects of diltiazem are better tolerated.
2. Resistant cases may benefit from injection of botulinum toxin or lateral internal sphincterotomy. Advancement flaps may be used to treat resistant cases.

The stapedius is the smallest skeletal muscle in the human body. At just over one millimetre in length, its purpose is to stabilize the smallest bone in the body, the stapes and is innervated by a branch of the facial nerve.

The correct order of structures from superficial to deep are: the skin and subcutaneous tissue, the external intercostals followed by internal intercostals, innermost intercostals and finally parietal pleura.

Electroencephalography (EEG) is the neurophysiological measurement of the electrical activity of the brain. It is done by placing electrodes on the scalp or subdurally. In reality, the electrical currents are not measured, but rather the voltage differences between different parts of the brain. Four major types of EEG activity are recognized, which are alpha, beta, delta and theta.
Alpha waves, also known as Berger’s waves ranges in frequency from 8-12 Hz. Best detected with eyes closed, alpha waves are characteristic of a relaxed, alert state of consciousness. An alpha-like normal variant called mu is sometimes seen over the motor cortex (central scalp) and attenuates with movement or, rather, with the intention to move.

The common femoral artery is the commonest site of arterial emboli causing acute limb ischemia. The treatment of choice is urgent femoral embolectomy.

The posterior interosseous nerve which causes, what is known as the posterior interosseous nerve syndrome. The nerve is compressed before it bifurcates to form the medial and lateral branches. The compression is beyond the origin of the branches to the radial wrist extensors and the radial sensory nerve. The result of such a case is paralysis of the digital extensors and the extensor carpi ulnaris, resulting in dorsoradial deviation of the wrist.

This is likely to be a case of simple duct ectasia. Normal USS report coupled with normal examination would favour discharge from the clinic. Mammography is generally not helpful in this age group.

Possible causes of nipple discharge include:
1. Abscess
2. Birth control pills
3. Breast cancer
4. Ductal carcinoma in situ (DCIS)
5. Endocrine disorders
6. Excessive breast stimulation
7. Fibrocystic breasts (lumpy or rope-like breast tissue)
8. Galactorrhoea
9. Injury or trauma to the breast
10. Intraductal papilloma (benign, wart-like growth in a milk duct)
11. Mammary duct ectasia
12. Mastitis (an infection in breast tissue that most commonly affects women who are breast-feeding)
13. Medication use
14. Menstrual cycle hormone changes
15. Paget’s disease of the breast
16. Periductal mastitis
17. Pregnancy and breast-feeding
18. Prolactinoma

Assessment and management of non-malignant nipple discharge includes:
1. Exclude endocrine disease
2. Nipple cytology is not carried out as it would be unhelpful
3. Smoking cessation advice given for duct ectasia
4. Total duct excision may be warranted for duct ectasia with severe symptoms

The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. A large number of muscles attach to the hyoid: Superiorly – the middle pharyngeal constrictor muscle, hyoglossus muscle, genioglossus, intrinsic muscles of the tongue and suprahyoid muscles. Inferiorly – the thyrohyoid muscle, omohyoid muscle and sternohyoid muscle.

Osteoarthritis is most common in older adults, predominating in women between the ages of 40 and 70; after this age, men and women are affected equally. It affects an entire joint, with disruption and potential loss of joint cartilage, along with other joint changes, including bone hypertrophy (osteophyte formation). The pain is usually gradual and is worse after activity, with occasional joint swelling. X-ray findings include marginal osteophytes, narrowing of the joint space, increased density of the subchondral bone, subchondral cyst formation, bony remodelling and joint effusions.