The administration of antibiotics is best considered therapeutic, rather than prophylactic, because of the high risk of infection in the absence of antibiotics.

Although debate still surrounds some aspects of antibiotic administration for open fractures, the following generalizations can be made:

– All patients with open fractures should receive cefazolin or equivalent gram-positive coverage; this may be sufficient
– Type II or type III injuries likely benefit from the addition of adequate gram-negative coverage, typically with an aminoglycoside
– Injuries at risk for anaerobic infections (e.g., farm injuries, severe tissue necrosis) probably benefit from the addition of penicillin or clindamycin.

Digital photos are helpful for documenting the initial appearance of the extremity and can be a valuable addition to the medical record. Digital imaging allows other members of the treatment team to see the wound preoperatively without repeated manipulations of the wound.
Gauze swabs soaked in normal saline are frequently used as dressing on open wounds.

The Oxford Handbook for Medical school recommends that open fractures should be sealed with saline-soaked gauze and impermeable dressing after removal of gross contaminants.

Superficial burns are confined in the depth of the epidermis, and all dermal appendages and nerve endings are intact. Superficial burns generally heal in 3 to 5 days with minimal intervention and do not leave significant scarring as they typically heal by re epithelialization. Therefore the sweat glands will be intact.

Flow in any vessel = Effective perfusion pressure divided by resistance, where effective perfusion pressure is the mean intraluminal pressure at the arterial end minus the mean pressure at the venous end. Thus, in the given problem, resistance = (60 − 20)/200 = 0.2 mmHg/ml per min.

Internal haemorrhoids are formed by varicosities of the branches of the superior rectal vein.
External haemorrhoids are formed by varicosities of the branches of the inferior rectal vein.

Fractures of the distal radius account for up to 20% of all fractures treated in the emergency department. Initial assessment includes a history of the mechanism of injury, associated injury and appropriate radiological evaluation
Most of the fractures are caused by a fall on the outstretched hand with the wrist in dorsiflexion. The form and severity of fracture of distal radius as well as the concomitant injury of disco-ligamentary structures of the wrist also depend on the position of the wrist at the moment of hitting the ground. The width of this angle influences the localization of the fracture. Pronation, supination and abduction determine the direction of the force and the compression of the carpus and different appearances of ligament injuries.
The basic principle of fracture treatment is to obtain accurate fracture reduction and then to use a method of immobilization that will maintain and hold that reduction. While the goal of treatment in fracture distal end of the radius is the restoration of normal function, the precise methods to achieve that desired outcome are controversial. Intra-articular fractures of the distal end of the radius can be difficult to treat, at times, with a traditional conservative method. A number of options for treatment are available to prevent the loss of reduction in an unstable fracture of the distal end of the radius.
One of the recent advances in the treatment of distal radius fractures is the more frequent application of open reduction and internal fixation, especially for intra-articular fractures. There are two groups of fractures for which open reduction and internal fixation is advisable.
The first group includes the two-part shear fracture (Barton fracture), which actually is a radio-carpal fracture-dislocation. Although the anatomical reduction is possible by closed means in some cases, these fractures are very unstable and difficult to control in plaster. The second group includes complex intra-articular fractures in which the articular fragments are displaced, rotated or impacted and are not amenable to reduction through limited operative exposure.

The fundus of the bladder is related anatomically to the anterior surface of the vagina and the urethra as well. If there was a malignant growth in the anterior surface of the vagina, then most likely the fundus of the bladder would be involved as well aspotentially the urethra.

Overproduction of aldosterone (a mineralocorticoid) by the adrenal glands is known as Conn’s syndrome. It can be either due to an aldosterone-secreting adrenal adenoma (50-60% cases) or adrenal gland hyperplasia (40-50% cases). Excess aldosterone leads to sodium and water retention, along with potassium excretion. This leads to arterial (non-essential) hypertension. Conn’s syndrome is the commonest cause of primary hyperaldosteronism. Other symptoms include muscle cramps, headache (due to hypokalaemia) and metabolic alkalosis, which occurs due to increased secretion of H+ ions by the kidney. The raised pH of the blood traps calcium leading to symptoms of hypocalcaemia, which can be mimicked by liquorice ingestion and Liddle syndrome. To diagnose Conn’s syndrome, the ratio of renin and aldosterone is measured. Due to suppression of renin secretion, there is low renin to aldosterone ratio (<0.05). However, anti-hypertensives may affect the test results and should be withdrawn for 6 weeks. Computed tomography can also be done to detect the presence of adrenal adenoma.
Cushing’s syndrome does not cause hypokalaemia with normal serum glucose levels. Nelson’s syndrome refers to increased ACTH secretion due to pituitary adenoma. Pheochromocytoma will not lead to hypokalaemia even though hypertension can be seen.

The medial umbilical ligament is a structure found on the deep surface of the anterior abdominal wall and is covered by the medial umbilical folds. It is a paired structure that represents the remnants of the fetal umbilical artery. They have no role in humans after birth other than to be used as a landmark for exploring the medial inguinal fossa during laparoscopic inguinal hernia repair.

Medial extension of an appendicectomy incision carries a risk of injury to the inferior epigastric artery which can bleed briskly. It is best managed by ligation.

Bleeding is a complication encountered in all branches of surgery. The decision as to how best to manage the bleed, depends upon its site, vessel, and circumstances.

1. Superficial dermal bleeding:
This will usually cease spontaneously. If not, then direct use of a monopolar or a bipolar cautery device will usually control the situation. Scalp wounds are a notable exception and bleeding from them may be brisk. In this situation, use of a mattress suture as a wound closure method will usually address the problem.

2. Superficial arterial bleeding:
If the vessel can be safely identified in superficial arterial bleeding, then the easiest method is to apply a haemostatic clip and ligate the vessel.

3. Major arterial bleeding:
If the vessel can be clearly identified and is accessible, then it may be possible to apply a clip and ligate the vessel. If the vessel is located in a pool of blood, then blind application of haemostatic clips is highly dangerous and may result in collateral injury. In this situation, evacuating the clot and packing the area is often safer. The pack can then be carefully removed when the required instruments are available. Some vessels may retract and bleeding may then be controlled by dissection of surrounding structures or underrunning the bleeding point.

4. Major venous bleeding:
The safest initial course of action is to apply digital pressure to the bleeding point. To control the bleeding, thereafter, the surgeon will need a working suction device. Divided veins may require ligation.

5. Bleeding from raw surfaces:
This may be mixed bleeding and can be troublesome. Spray diathermy and argon plasma coagulation are both useful agents. Certain topical haemostatic agents, such as surgicel, are useful in encouraging clot formation and may be used in conjunction with, or instead of, the above agents.

As most of the coagulation factors are synthesized in the liver, liver diseases like hepatitis or cirrhosis will depress the coagulation system. Vitamin K deficiency can also decrease the production of vitamin K dependent coagulation factors VII, XI, X and prothrombin.

Normal values for various parameters are as follows:
Systolic arterial blood pressure (SBP): 90–140 mmHg.
Diastolic arterial blood pressure: 60–90 mmHg.
Mean arterial blood pressure (MAP): SBP + (2 × DBP)/3 (normal range: 70-105 mmHg).
Right atrial pressure (RAP): 2–6 mmHg.
Systolic right ventricular pressure (RVSP): 15–25 mmHg.
Diastolic right ventricular pressure (RVDP): 0–8 mmHg.
Pulmonary artery pressure (PAP): Systolic (PASP) is 15-25 mmHg and Diastolic (PADP) is 8–15 mmHg.
Pulmonary artery wedge pressure (PAWP): 6–12 mmHg.
Left atrial pressure (LAP): 6–12 mmHg.
Thus, the given value indicates that the position of catheter tip is likely to be in the pulmonary artery.

A neuroendocrine tumour of the chromaffin cells in adrenal medulla, pheochromocytoma secretes excessive catecholamines – adrenaline (epinephrine) and noradrenaline (norepinephrine). Pheochromocytomas are also known as the ‘10% tumour’. This is because 10% of them are bilateral, 10% are malignant, and 10% are extra-adrenal. Extra-adrenal paragangliomas (also known as extra-adrenal pheochromocytomas) are less common than pheochromocytomas and arise in the ganglia of sympathetic nervous system. Around 25% of pheochromocytomas are familial. Symptoms are described as feeling of ‘impending doom’, and include tachycardia, hypertension, palpitations, anxiety, headaches and pallor. Orthostatic hypertension is typically seen where there is a more than 100 mmHg fall in systolic pressure when the patient stands up. Pheochromocytomas can also lead to malignant hypertension. Diagnosis is by measurement of catecholamines and metanephrines in blood or in 24-hour urine, after exclusion of other possible causes such as stress, hypoglycaemia and drugs (methyldopa, dopamine agonists, ganglion-blocking antihypertensive). Imaging is also needed to localize the tumour. Localization of the tumour can also be done by Iodine-131 meta-iodobenzylguanidine (I131-MIBG) imaging.

In atrial fibrillation, the abnormal atrial contraction can cause blood to stagnate in the left atrium and form a thrombus, which may then embolize. The patient’s history of AF suggest an embolic disease, which lead to his death.

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.

Hypermagnesemia is an electrolyte disturbance in which there is a high level of magnesium in the blood. It is defined as a level greater than 1.1 mmol/L. Symptoms include weakness, confusion, decreased breathing rate, and cardiac arrest.

The foramen magnum is found in the most inferior part of the posterior cranial fossa. It is traversed by vital structures including the medulla oblongata. Its contents include the following: medulla oblongata, meninges, spinal root of the accessory nerve, vertebral arteries, anterior and posterior spinal arteries, tectorial membrane and alar ligaments.

Minimal-change disease (MCD) refers to a histopathologic glomerular lesion, typically found in children, that is almost always associated with nephrotic syndrome. The most noticeable symptom of MCD is oedema, which can develop very rapidly. Due to the renal loss of proteins muscle wasting and growth failure may be seen in children. Renal function is usually not affected and a proteinuria of more than 40 mg/h/m2 is the only abnormal finding in urinalysis.

In the given problem, there is respiratory acidosis due to hypercapnia from a low respiratory rate and/or volume (hypoventilation). Causes of hypoventilation include conditions impairing the central nervous system (CNS) respiratory drive, impaired neuromuscular transmission and other causes of muscular weakness (drugs and sedatives), along with obstructive, restrictive and parenchymal pulmonary disorders. Hypoventilation leads to hypoxia and hypercapnia reduces the arterial pH. Severe acidosis leads to pulmonary arteriolar vasoconstriction, systemic vascular dilatation, reduced myocardial contractility, hyperkalaemia, hypotension and cardiac irritability resulting in arrhythmias. Raised carbon dioxide concentration also causes cerebral vasodilatation and raised intracranial pressure. Over time, buffering and renal compensation occurs. However, this might not be seen in acute scenarios where the rise in p(CO2) occurs rapidly.

The elbow joint is one of the many synovial joints in the body. This joint is an example of the hinge joint as the humerus is received into the semilunar notch of the ulna and the capitulum of the humerus articulates with the fovea on the head of the radius, together acting as a hinge in one plane.

The symptoms suggest Cushing syndrome due to increased glucocorticoid levels. One cause of Cushing syndrome is ectopic production of adrenocorticotrophic hormone from oat cell carcinoma. As oat cell carcinoma is known to be highly metastatic, the tenderness in lower back could represent metastatic involvement.