Actinomycosis is primarily caused by any of the several members of the bacterial genus Actinomyces. These bacteria are generally anaerobes. And can cause multiple abscesses that may discharge sulphur granules.

Hypertension in a young patient without any obvious cause should be investigated.

A pheochromocytoma is a catecholamine-secreting tumour typically located in the adrenal medulla. Pheochromocytomas are usually benign (∼ 90% of cases) but may also be malignant. Classic clinical features are due to excess sympathetic nervous system stimulation and involve episodic blood pressure crises with paroxysmal headaches, diaphoresis, heart palpitations, and pallor. However, a pheochromocytoma may also present asymptomatically or with persistent hypertension. Elevated catecholamine metabolites in the plasma or urine confirm the diagnosis, while imaging studies in patients with positive biochemistry are used to determine the location of the tumour. Surgical resection is the treatment of choice, but is only carried out once alpha blockade with phenoxybenzamine has become effective.

Pheochromocytoma is said to follow a 10% rule:

,10% are extra-adrenal
,10% are bilateral
,10% are malignant
,10% are found in children
,10% are familial
,10% are not associated with hypertension
,10% contain calcification

The loop of Henlé leads from the proximal convoluted tubule to the distal convoluted tubule. Its primary function uses a counter current multiplier mechanism in the medulla to reabsorb water and ions from the urine. It can be divided into four parts:
1. Descending limb of loop of Henlé – low permeability to ions and urea, while being highly permeable to water 2. Thin ascending limb of loop of Henlé – not permeable to water, but it is permeable to ions
3. Medullary thick ascending limb of loop of Henlé – sodium (Na+), potassium (K+) and chloride (Cl–) ions are reabsorbed by active transport. K+ is passively transported along its concentration gradient through a K+ channel in the basolateral aspect of the cells, back into the lumen of the ascending limb.
4. The cortical thick ascending limb – the site of action where loop diuretics such as furosemide block the K+/Na+/2Cl− co-transporters = reduced active transport.

The carina (a keel-like cartilage) is found at the bifurcation of the trachea separating the right from the left main stem bronchi. It is a little more to the left than to the right.
The cricoid cartilage is the inferior and posterior cartilage of the larynx.
The costal cartilage on the other hand elongates the ribs anteriorly and contribute to the elasticity of the thoracic cage.
The pulmonary ligament is a fold of pleura located below the root of the lung.
Tracheal rings are rings of cartilage that support the trachea.
Peritracheal fascia is a layer of connective tissue that invests the trachea from the outside and is not visible on bronchoscopy.

Post-operative fever is very common.
It is known to occur after all types of surgical procedures, irrespective of the type of anaesthesia.
Postoperative fever can occur after minor surgical procedures but is rare and depends on the type of procedure. Overall, both abdominal and chest procedures result in the highest incidence of postoperative fever.

In this case:
Acute Fever
Fever occurs in the first week (1 to 7 POD)
POD 7 (5 to 10): Wound infection: Risk increases if the patient is immunocompromised (e.g., diabetic), abdominal wound, duration of surgery greater than 2 hours or contamination during surgery. Signs include erythema, warmth, tenderness, discharge.
Rule out abscess or collections by physical exam plus ultrasound if needed. If an abscess is present, drainage and antibiotics are needed. Prevention is by careful surgical technique and prophylactic antibiotics (e.g., intravenous cefazolin at the time of induction of anaesthesia as well as postoperatively if needed)

Other causes of Postoperative fever:
An Immediate Fever
Fever occurs immediately after surgery or within hours on postoperative days (POD) 0 or 1.
– Malignant hyperthermia: high-grade fever (greater than 40 C), occurs shortly after inhalational anaesthetics or muscle relaxant (e.g., halothane or succinylcholine), may have a family history of death after anaesthesia. Laboratory studies will reveal with metabolic acidosis and hypercalcemia. If not readily recognized, it can cause cardiac arrest. The treatment is intravenous dantrolene, 100% oxygen, correction of acidosis, cooling blankets, and watching for myoglobinuria.
– Bacteraemia: High-grade fever (greater than 40 C) occurring 30 to 40 minutes after the beginning of the procedure (e.g., Urinary tract instrumentation in the presence of infected urine). Management includes blood cultures three times and starting empiric antibiotics.
– Gas gangrene of the wound: High-grade fever (greater than 40 C) occurring after gastrointestinal (GI) surgery due to contamination with Clostridium perfringens; severe wound pain; treat with surgical debridement and antibiotics.
– Febrile non-haemolytic transfusion reaction: Fevers, chills, and malaise 1 to 6 hours after surgery (without haemolysis). Management: Stop transfusion (rule out haemolytic transfusion reaction) and give antipyretics (avoid aspirin in the thrombocytopenic patient).

B. Acute Fever
– Fever occurs in the first week (1 to 7 POD).
POD 1 to 3: atelectasis: After prolonged intubation, the presence of upper abdominal incision, inadequate postoperative pain control, lying supine. Should be prevented by incentive spirometry, semi-recumbent position, adequate pain control, early ambulation. Clinically may be asymptomatic or with increased work of breathing, respiratory alkalosis, chest x-ray with volume loss. Treatment includes spirometry, chest physiotherapy, semi-recumbent position (improves expansion of alveoli by preventing pressure from intra-abdominal organs on the diaphragm and hence improving functional residual capacity)
– POD 3: Unresolved atelectasis resulting in pneumonia (respiratory symptoms, Chest x-ray with infiltrate or consolidation, sputum culture, empiric antibiotics and modify according to culture result and sensitivity), or development of urinary tract infection (urine analysis and culture, treat with empiric antibiotics and modify according to culture result and sensitivity)
– POD 5: Thrombophlebitis (may be asymptomatic or symptomatic, diagnose with Doppler ultrasound of deep leg and pelvic veins and treat with heparin)
– POD 7: Pulmonary embolism (tachycardia, tachypnoea, pleuritic chest pain, ECG with right heart strain pattern (a low central venous pressure goes against diagnosis), arterial blood gas with hypoxemia and hypocapnia, confirm diagnosis with CT angiogram, and treat with heparin, if recurrent pulmonary embolism while anticoagulated with therapeutic INR, Inferior vena cava filter placement is the next step

C. Subacute Fever
Fever occurs between postoperative weeks 1 and 4.
– POD 10: Deep infection (pelvic or abdominal abscess and if abdominal abscess could be sub-hepatic or sub-phrenic). A digital rectal exam to rule out the pelvic abscess and CT scan to localize intra-abdominal abscess. Treatment includes re-exploration vs. radiological guided percutaneous drainage
Drugs: Diagnosis of exclusion includes rash and peripheral eosinophilia

D. Delayed Fever
Fever after more than 4 weeks.
Skin and soft tissue infections (SSTI)
Viral infections

The oesophagus is divided into 3 portions: cervical (part that is in the neck), thoracic portion and the abdominal portion. The cervical part is bordered by the trachea anteriorly and the prevertebral fascia covering the bodies of the 6,7 and 8th vertebra posteriorly. The thoracic duct lies on the left side at the level of the sixth cervical vertebra. The carotid sheath with its contents and lower poles of the lateral lobes of thyroid gland are lateral. The thoracic duct is the structure most likely to be injured.

The immediate treatment of hypercalcaemia involves intravenous fluid resuscitation. This may be complemented with the use of bisphosphonates and sometimes, diuretics. However, fluids are administered first. Normal saline is usually preferred for this over other solutions.

Urgent management in hypercalcaemia is indicated if:
1. Serum calcium level >3.5 mmol/L
2. Reduced consciousness
3. Severe abdominal pain
4. Pre-renal failure

Management options include:
1. Intravenous fluid resuscitation with 3–6 litres of 0.9% normal saline in 24 hours
2. Concurrent administration of calcitonin to help lower calcium levels
3. Medical therapy (usually if corrected calcium >3.0mmol/L)

Answer: Myoglobin

When muscle is damaged, a protein called myoglobin is released into the bloodstream. It is then filtered out of the body by the kidneys. Myoglobin breaks down into substances that can damage kidney cells.
Compartment syndrome is a painful condition that occurs when pressure within the muscles builds to dangerous levels. This pressure can decrease blood flow, which prevents nourishment and oxygen from reaching nerve and muscle cells.

Compartment syndrome can be either acute or chronic.

Acute compartment syndrome is a medical emergency. It is usually caused by a severe injury. Without treatment, it can lead to permanent muscle damage.

Chronic compartment syndrome, also known as exertional compartment syndrome, is usually not a medical emergency. It is most often caused by athletic exertion. Compartments are groupings of muscles, nerves, and blood vessels in your arms and legs. Covering these tissues is a tough membrane called a fascia. The role of the fascia is to keep the tissues in place, and, therefore, the fascia does not stretch or expand easily.
Compartment syndrome develops when swelling or bleeding occurs within a compartment. Because the fascia does not stretch, this can cause increased pressure on the capillaries, nerves, and muscles in the compartment. Blood flow to muscle and nerve cells is disrupted. Without a steady supply of oxygen and nutrients, nerve and muscle cells can be damaged.

In acute compartment syndrome, unless the pressure is relieved quickly, permanent disability and tissue death may result. This does not usually happen in chronic (exertional) compartment syndrome.

Compartment syndrome most often occurs in the anterior (front) compartment of the lower leg (calf). It can also occur in other compartments in the leg, as well as in the arms, hands, feet, and buttocks.

Acute compartment syndrome usually develops after a severe injury, such as a car accident or a broken bone. Rarely, it develops after a relatively minor injury.

Conditions that may bring on acute compartment syndrome include:

A fracture.
A badly bruised muscle. This type of injury can occur when a motorcycle falls on the leg of the rider, or a football player is hit in the leg with another player’s helmet.
Re-established blood flow after blocked circulation. This may occur after a surgeon repairs a damaged blood vessel that has been blocked for several hours. A blood vessel can also be blocked during sleep. Lying for too long in a position that blocks a blood vessel, then moving or waking up can cause this condition. Most healthy people will naturally move when blood flow to a limb is blocked during sleep. The development of compartment syndrome in this manner usually occurs in people who are neurologically compromised. This can happen after severe intoxication with alcohol or other drugs.
Crush injuries.
Anabolic steroid use. Taking steroids is a possible factor in compartment syndrome.
Constricting bandages. Casts and tight bandages may lead to compartment syndrome. If symptoms of compartment syndrome develop, remove or loosen any constricting bandages.

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.

Metoclopramide is a potent dopamine-receptor antagonist with anti-emetic and prokinetic properties. It is therefore commonly used to treat nausea and vomiting, and to facilitate gastric emptying in patients with gastric stasis. The anti-emetic action of metoclopramide is due to its antagonist activity at D2 receptors in the chemoreceptor trigger zone (CTZ) in the central nervous system. Common adverse drug reactions associated with metoclopramide include restlessness (akathisia), and focal dystonia.

The correct treatment for an infected sebaceous cyst is incision and drainage with removal of the cyst wall. Conservation of the cyst wall invariably leads to recurrence. Furthermore, the infected wound must not be primarily closed. The administration of antibiotics without drainage of sepsis is futile.

A sebaceous cyst is a rounded swollen area of the skin formed by an abnormal sac of retained excretion (sebum) from the sebaceous follicles. It can occur anywhere but is most commonly formed on scalp, ears, back, face, and upper arm (not on palms of the hands and soles of the feet). The correct treatment for an infected sebaceous cyst is incision and drainage with removal of the cyst wall. Excision of the cyst wall needs to be complete to prevent recurrence.

Cock’s peculiar tumour is a suppurating and ulcerated sebaceous cyst, which may resemble a squamous cell carcinoma.

The inferior rectus muscle is a muscle in the orbit. As with most of the muscles of the orbit, it is innervated by the inferior division of oculomotor nerve (Cranial Nerve III). It depresses, adducts, and helps laterally rotate the eye.

The suprachiasmatic nucleus (SCN) in the hypothalamus is responsible for controlling endogenous circadian rhythms and destruction of the SCN leads to a loss of circadian rhythm.

If patients need IV fluids for routine maintenance alone, restrict the initial prescription to:
25–30 ml/kg/day of water and
approximately 1 mmol/kg/day of potassium, sodium and chloride and
approximately 50–100 g/day of glucose to limit starvation ketosis.
Weight-based potassium prescriptions should be rounded to the nearest common fluids available (for example, a 67 kg person should have fluids containing 20 mmol and 40 mmol of potassium in 24 hours). Potassium should not be added to intravenous fluid bags as this is dangerous.

Sodium chloride 0.9%, with or without additional potassium, is one of the most commonly used IV fluids in UK practice.

Glucose 5% solution provides a useful means of giving free water for, once the glucose is metabolised, the fluid is distributed throughout total body water. It is, therefore, a potentially useful means of correcting or preventing simple dehydration and the glucose content will also help to prevent starvation ketosis, although it is important to recognize that it will not make much of a contribution to covering patients overall nutritional needs. The use of 5% glucose, will increase risks of significant hyponatraemia, particularly in children, the elderly, patients on diuretics and those with excess ADH due to osmotic and non-osmotic stimuli (a problem is seen quite frequently in hospitalized patients). Nevertheless, hyponatremia is likely to be avoided by not exceeding recommended volumes of maintenance IV fluids and by careful monitoring of patients’ clinical volume status and electrolyte measurements.

Spermatic or testicular veins arise from the posterior aspect of the testis and receive tributaries from the epididymis. Upon uniting, they form the pampiniform plexus that makes up the greater mass of the spermatic cord. The vessels that make up this plexus rise up the spermatic cord in front of the ductus deferens. They then unite, below the superficial ring, to form three or four veins that traverse the inguinal canal and enter the abdomen through the deep inguinal ring. They further unite to form 2 veins that ascend up the psoas major muscle behind the peritoneum each lying on either side of the testicular artery. These further unite to form one vein that empties on the right side of the inferior vena cava at an acute angle and on the left side into the renal vein, at a right angle. The left testicular vein courses behind the iliac colon and is thus exposed to pressure from the contents of this part of the bowel. The ovarian vein is the equivalent of the testicular vein in women. They form a plexus in the broad ligament near the ovary and uterine tube and communicate with the uterine plexus. They drain into similar vessels as in a man.

The popliteal fossa is located at the back of the knee. It is bounded laterally by the biceps femoris above and the plantaris and lateral head of the gastrocnemius below and medially by the semitendinosus and semimembranosus above and by the medial head of the gastrocnemius below.

Mesosalpinx is the portion of the broad ligament that stretches from the fallopian tube to the ovary and contains the uterine tubes between it’s layers.

As the inferior gluteal nerve emerges from the greater sciatic foramen below the piriformis muscle, it divides into branches and enters the gluteus maximus muscle which extends the femur and bends the thigh in line with the body.

For a rib fracture to cause pneumothorax, there must also be laceration to the underlying lung parenchyma. This has the risk of developing into a tension pneumothorax. Therefore, a chest drain should be inserted and the patient admitted.

Pneumothorax is a collection of free air in the chest cavity that causes the lung to collapse. The most common cause of pneumothorax is lung laceration with air leakage. In some instances, the lung continues to leak air into the chest cavity and results in compression of the chest structures, including vessels that return blood to the heart. This is known as a tension pneumothorax and can be fatal if not treated immediately. Blunt or penetrating chest trauma that creates a flap-type defect on the surface of the lung can result in this life-threatening condition.

Acute subdural hematoma is usually caused by external trauma that creates tension in the wall of a bridging vein as it passes between the arachnoid and dural layers of the brain’s lining—i.e., the subdural space. The circumferential arrangement of collagen surrounding the vein makes it susceptible to such tearing.

Acute bleeds often develop after high-speed acceleration or deceleration injuries. They are most severe if associated with cerebral contusions. Though much faster than chronic subdural bleeds, acute subdural bleeding is usually venous and therefore slower than the arterial bleeding of an epidural haemorrhage. Acute subdural hematomas due to trauma are the most lethal of all head injuries and have a high mortality rate if they are not rapidly treated with surgical decompression. The mortality rate is higher than that of epidural hematomas and diffuse brain injuries because the force required to cause subdural hematomas tends to cause other severe injuries as well.

Generally, acute subdural hematomas are less than 72 hours old and are hyperdense compared with the brain on computed tomography scans. The subacute phase begins 3-7 days after acute injury. Chronic subdural hematomas develop over the course of weeks and are hypodense compared with the brain. However, subdural hematomas may be mixed in nature, such as when acute bleeding has occurred into a chronic subdural hematoma.
Lateralizing findings include ipsilateral pupillary dilatation with impaired reaction and motor deficit. Usually the pupillary dilatation will be ipsilateral and motor deficit (hemiparesis or hemiplegia) will be contralateral to the site of subdural hematoma.

Diarrhoea can occur due to any of the numerous aetiologies, which include infectious, drug-induced, food related, surgical, inflammatory, transit-related or malabsorption. Four mechanisms have been implicated in diarrhoea: increased osmotic load, increased secretion, inflammation and decreased absorption time. Diarrhoea can result in fluid loss with consequent dehydration, electrolyte loss (Na+, K+, Mg2+, Cl–) and even vascular collapse. Loss of bicarbonate ions can lead to a metabolic acidosis.

The flexor retinaculum is immediately posterior to the medial malleolus. The structures that pass under the flexor retinaculum from anterior to posterior are: tendon of the tibialis posterior, flexor digitorum longus, posterior tibial artery (and vein), tibial nerve and tendon of flexor hallucis longus. The tibial nerve is the only one which lies behind the flexor retinaculum.

The medial epicondyle of the humerus is the site of origin of this group of muscles of the forearm. It originates from the medial epicondyle of the humerus by a common tendon. Fibres from the deep fascia of the forearm, near the elbow and septa, pass from this fascia between the muscles. These muscles include the pronator teres, palmaris longus, flexor carpi radialis, flexor carpi ulnaris and flexor digitorum superficialis.

Chemotherapy for acute myeloid leukaemia (AML) requires long-term therapy and multiple blood tests. Therefore, an indwelling device, such as Groshong line, is preferable.

Tunnelled lines such as Groshong and Hickman lines are popular devices for patients with long-term therapeutic requirements. These devices are usually inserted, using ultrasound guidance, into the internal jugular vein and then tunnelled under the skin. A cuff of woven material is sited near the end and helps to anchor the device into the tissues. These cuffs require formal dissection to allow the device to be removed.

Upper gastrointestinal (GI) bleeding is usually defined by a bleeding source proximal to the ligament of Treitz although some may also include a bleeding source in the proximal jejunum. Upper GI bleeding emergencies are characterized by hematemesis, melena, haematochezia (if the bleeding is massive and brisk) and evidence of hemodynamic compromise such as dizziness, syncope episodes and shock. The most commonly used endoscopic haemostatic interventions include epinephrine (adrenaline) injection, thermal coagulation and endoscopic clipping at the ulcer site to constrict, compress and/or destroy the bleeding vessel. Injection of 30 mL diluted epinephrine (1:10 000) can effectively prevent recurrent bleeding with a low rate of complications. The optimal injection volume of epinephrine for endoscopic treatment of an actively bleeding ulcer (spurting or oozing) is 30 mL.

Lung abscesses are collections of pus within the lung that arise most commonly as a complication of aspiration pneumonia caused by oral anaerobes. Older patients are more at risk due to poor oral hygiene, gingivitis an inability to handle their oral secretions due to other diseases. Chest X-ray most commonly reveals the appearance of an irregularly shaped cavity with an air-fluid level.

Meningiomas are a common benign intracranial tumour, and their incidence is higher in women between the ages of 40-60 years old. Many of these tumours are asymptomatic and are diagnosed incidentally, although some of them may have malignant presentations (less than 2% of cases). These benign tumours can develop wherever there is dura, over the convexities near the venous sinuses, along the base of the skull, in the posterior fossa and, within the ventricles.

The basilar artery is part of the vertebrobasilar system. It is formed by the confluence of the two vertebral arteries which arise from the subclavian arteries. These two vertebral arteries merge at the level of cranial nerve VI at the junction between the pons and the medulla oblangata to form what is know as the basilar artery. This vertebrobasilar system supplies the upper spinal cord, brainstem, cerebellum, and posterior part of brain.

Catheter-directed thrombolysis (CDT) is recommended as the next step of management for patients with proximal upper-extremity deep vein thrombosis (UEDVT) of recent onset or severe symptoms.

Primary UEDVT is less common than secondary forms. The most common primary form is effort-related thrombosis, also called Paget-Schroetter syndrome. It usually occurs in otherwise healthy young men who report, before the onset of thrombosis, vigorous arm exercise such as lifting weights, playing badminton, pitching a baseball, or performing repetitive overhead activities, such as painting or car repair. Most patients with effort-related UEDVT have an underlying venous thoracic outlet syndrome (VTOS). Secondary causes of UEDVT include central line insertion, malignancy, or pacemakers.

Patients with UEDVT typically present with heaviness, discomfort, pain, paraesthesia, and swelling of the affected arm. Physical examination may reveal pitting oedema, redness, or cyanosis of the involved extremity; visible collateral veins at the shoulder or upper arm; and fever.

Diagnosis is made by:
1. FBC: platelet function
2. Coagulation profile
3. Liver function tests
4. Duplex scan: investigation of choice
5. D-dimer testing
6. CT scan: for VTOS

Treatment options for primary UEDVT are as follows:
1. Anticoagulation therapy should be undertaken with a once-daily regimen of LMWH or fondaparinux for at least five days, followed by vitamin K antagonists for at least three months. Unfractionated heparin instead of LMWH is recommended for patients with renal failure or for those treated with CDT.

2. Early thrombus removal and restoration of venous patency should be done immediately after starting the patient on heparin. Catheter-based therapy is recommended for patients with proximal UEDVT of recent onset and severe symptoms, low risk for bleeding complications, and good functional status.

After a patient has undergone total colectomy and ileostomy, the volume of ileal discharge, along with its water content gradually decreases over time. Post surgery, most patients can live a normal life. Iron and vitamin B12 absorption do not take place in the colon and hence are not affected significantly by a colectomy.