Using fluids to correct hypovolaemia is a dynamic process that requires ongoing evaluation of clinical and haemodynamic indices. Thus, the use of the fluid challenge provides a successful method of adjusting the fluid volume to the patient’s need.

The fluid challenge is a method of safely restoring circulating volume according to physiological need rather than using fixed haemodynamic end-points. The fluid is given in small aliquots to produce a known increment in circulating volume with an assessment of the dynamic haemodynamic response to each aliquot. No fixed haemodynamic end-point is assumed and the technique provides a diagnostic test of hypovolaemia (via an appropriate positive response of the circulation to fluid) and a method of titrating the optimal dose of fluid to the individual’s requirement.
The response of SV and/or CVP (or PAWP) should be monitored during a fluid challenge. The basis of the fluid challenge is to achieve a known increase in intravascular volume by rapid infusion of a bolus of colloid fluid (200 ml).
In the inadequately filled left ventricle, a fluid challenge will increase SV. Failure to increase SV with a fluid challenge may indicate a circulation that is unresponsive to fluid or an inadequate challenge.

Oesophageal atresia encompasses a group of congenital anomalies comprising an interruption of the continuity of the oesophagus combined with or without a persistent communication with the trachea.
The diagnosis of oesophageal atresia may be suspected prenatally by the finding of a small or absent fetal stomach bubble on an ultrasound scan performed after the 18th week of gestation. Overall the sensitivity of ultrasonography is 42% but in combination with polyhydramnios, the positive predictive value is 56%. Polyhydramnios alone is a poor indicator of oesophageal atresia (1% incidence).
The newborn infant of a mother with polyhydramnios should always have a nasogastric tube passed soon after delivery to exclude oesophageal atresia. Infants with oesophageal atresia are unable to swallow saliva and are noted to have excessive salivation requiring repeated suctioning. At this stage, and certainly, before the first feed, a stiff wide-bore (10–12 French gauge) catheter should be passed through the mouth into the oesophagus. In oesophageal atresia, the catheter will not pass beyond 9–10 cm from the lower alveolar ridge. A plain X-ray of the chest and abdomen will show the tip of the catheter arrested in the superior mediastinum (T 2–4) while gas in the stomach and intestine signifies the presence of a distal tracheoesophageal fistula. The absence of gastrointestinal gas is indicative of isolated atresia. A fine bore catheter may curl up in the upper pouch giving the false impression of an intact oesophagus or rarely it may pass through the trachea and proceed distally into the oesophagus through the fistula. The X-ray may reveal additional anomalies such as a double bubble appearance of duodenal atresia, vertebral or rib abnormalities.
Delaying the diagnosis until the infant presents with coughing and choking during the first feed is no longer acceptable in modern paediatric practice.

Duodenal atresia is typically characterized by the onset of vomiting within hours of birth. While vomitus is most often bilious, it may be nonbilious because 15% of defects occur proximal to the ampulla of Vater.

Pyloric stenosis, also known as infantile hypertrophic pyloric stenosis (IHPS), is the most common cause of intestinal obstruction in infancy. IHPS occurs secondary to hypertrophy and hyperplasia of the muscular layers of the pylorus, causing a functional gastric outlet obstruction.
Classically, the infant with pyloric stenosis has nonbilious vomiting or regurgitation, which may become projectile (in as many as 70% of cases), after which the infant is still hungry.
Emesis may be intermittent initially or occur after each feeding.
Emesis should not be bilious as the obstruction is proximal to the common bile duct. The emesis may become brown or coffee colour due to blood secondary to gastritis or a Mallory-Weiss tear at the gastroesophageal junction.
As the obstruction becomes more severe, the infant begins to show signs of dehydration and malnutrition, such as poor weight gain, weight loss, marasmus, decreased urinary output, lethargy, and shock.
The infant may develop jaundice, which is corrected upon correction of the disease.

Optimal physical assessment of an anorectal abscess may require anaesthesia to alleviate patient discomfort that would otherwise limit the extent of the examination.
Drainage should be carried out promptly to prevent the sepsis worsening. Perianal incisions to allow drainage of pus should be circumanal, thus reducing the likelihood of damage to the sphincters and thereby preventing faecal incontinence.

Chronic cholecystitis can be a surgical challenge due to an inflammatory process that creates multiple adhesions, complicates dissection, and can hamper recognition of normal anatomical structures. In such cases cholecystostomy can be performed in order to alleviate the acute symptoms. Tube cholecystostomy allows for resolution of sepsis and delay of definitive surgery. Interval laparoscopic cholecystectomy can be safely performed once sepsis and acute infection has resolved.

QT interval extends from beginning of the QRS complex till the end of he T-wave and normally lasts for 0.40 s. It is important in the diagnosis of long-QT and short-QT syndrome. The QT interval varies on the basis of heart rate and may need to be corrected.

A congenital heart disease, ASD or atrial septal defect leads to a communication between the right and left atria due to a defect in the interatrial septum. This leads to mixing of arterial and venous blood from the right and left side of the heart. The hemodynamic significance of this defect depends on the presence of shunting of blood. Normally, the left side of the heart has higher pressure than the right as the left side has to pump blood throughout the body. A large ASD (> 9 mm) will result in a clinically significant left-to-right shunt, causing volume overload of the right atrium and ventricle, eventually leading to heart failure. Cardiac catheterization would reveal very high oxygen saturation in the right atrium, right ventricle and pulmonary artery. Eventually, the left-to-right shunt will lead to pulmonary hypertension and increased afterload in the right ventricle, along with the increased preload due to the shunted blood. This will either cause right ventricular failure, or raise the pressure in the right side of the heart to equal or more than that in the left. Elevation of right atrial pressure to that of left atrial pressure would thus lead to diminishing or complete cessation of the shunt. If left uncorrected, there will be reversal of the shunt, known as Eisenmenger syndrome, resulting in clinical signs of cyanosis as the oxygen-poor blood form right side of the heart will mix with the blood in left side and reach the peripheral vascular system.

Tracheobronchial lymph nodes are located at the bifurcation of the trachea and are in three groups i.e. the right superior, left superior and inferior. The aorta arches over the left bronchus near the point of tracheal bifurcation. Thus, the nerves that are closely associated with the aorta might be irritated if these nodes become inflamed. The left recurrent laryngeal nerve is such a nerve. The phrenic nerves, both the left and the right, are lateral and thus would not be affected. The right recurrent nerve loops around the right subclavian artery and is distant from this area. The right vagus artery is not associated with the aorta and the sympathetic chain is located in the posterior chest parallel to the vertebra, also not associated with the tracheobronchial tree.

Carbon dioxide is transported in the blood in various forms:
– Bicarbonate (80–90%)
– Carbamino compounds (5–10%)
– Physically dissolved in solution (5%).
Carbon dioxide is carried on the haemoglobin molecule as carbamino-haemoglobin; carboxyhaemoglobin is the combination of haemoglobin with carbon monoxide.

Hyaline thrombi are typically associated with thrombotic thrombocytopenic purpura (TTP), which is caused by non-immunological destruction of platelets. Platelet transfusion is contraindicated in TTP. Platelets and red blood cells also get damaged by loose strands of fibrin deposited in small vessels. Multiple organs start developing platelet-fibrin thrombi (bland thrombi with no vasculitis) typically at arteriocapillary junctions. This is known as ‘thrombotic microangiopathy’. Treatment consists of plasma exchange.

The efferent lymphatics from the anal canal proceed to the internal iliac lymph nodes. This would most likely form the site of enlargement in the lymphatics.

In this patient, a blocked catheter is the case because the urine is flowing into the urostomy bag but it is not able to pass through the catheter.
It is recommended that in cases without hypotension, a bladder washout should be done if there is clot retention. The catheter may also be changed.

Cardiac diastole refers to the time period when the heart is relaxed after contraction and is preparing to refill with blood. Both ventricular and atrial diastole are together known as complete cardiac diastole. At its beginning, the ventricles relax, causing a drop in the ventricular pressure. As soon as the left ventricular pressure drops below that in left atrium, the mitral valve opens and there is ventricular filling of blood. Similarly, the tricuspid valve opens filling the right atrium.

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.

Inflammatory breast cancer is a rare form of advanced, invasive carcinoma, characterized by dermal lymphatic invasion of tumour cells. Most commonly a ductal carcinoma.
Clinical features include erythematous and oedematous (peau d’orange) skin plaques over a rapidly growing breast mass. Tenderness, burning sensation, blood-tinged nipple discharge. Axillary lymphadenopathy is usually present. 25% of patients have metastatic disease at the time of presentation.
Differential diagnosis includes mastitis, breast abscess, Paget disease of the breast
Treatment is usually done with chemotherapy + radiotherapy + radical mastectomy. This type of cancer is usually associated with a poor prognosis. 5-year survival with treatment: ∼ 50% (without treatment: < 5%)

This patient has a Bankart lesion which is the most common underlying abnormality in recurrent anterior dislocation of the shoulder.

Bankart lesion is an injury of the anterior (inferior) glenoid labrum of the shoulder due to anterior shoulder dislocation. When this happens, a pocket at the front of the glenoid forms that allows the humeral head to dislocate into it. It is usually visualised by CT and MRI scanning and is often repaired arthroscopically.

Shoulder fractures and dislocations usually result from low-energy falls in predominantly elderly females or from high-energy trauma in young males. They can be associated with nerve injury (commonly axillary), and fracture-dislocation of the humeral head. Anterior shoulder dislocation (glenohumeral dislocation) is the most common type of shoulder dislocation (>90%) and is usually traumatic in nature.

Early assessment of shoulder dislocation:
Careful history, examination, and documentation of neurovascular status of the upper limb, in particular the axillary nerve, is important. This should be re-assessed after manipulation. Early radiographs should also be done to confirm the direction of the dislocation.

Initial management of anterior dislocation:
It consists of emergent closed reduction (to prevent lasting chondral damage) under Entonox and analgesia, but often requires conscious sedation. The affected arm should then be immobilised in a polysling. Initial management requires emergent reduction to prevent lasting chondral damage.

An anal fissure is a painful linear tear or crack in the distal anal canal, which, in the short term, usually involves only the epithelium and, in the long term, involves the full thickness of the anal mucosa. Typically, the patient reports severe pain during a bowel movement, with the pain lasting several minutes to hours afterward. The pain recurs with every bowel movement, and the patient commonly becomes afraid or unwilling to have a bowel movement, leading to a cycle of worsening constipation, harder stools, and more anal pain. Approximately 70% of patients note bright-red blood on the toilet paper or stool. Occasionally, a few drops may fall in the toilet bowl, but significant bleeding does not usually occur with an anal fissure.
Second-line medical therapy consists of intra-anal application of 0.4% nitro-glycerine (NTG; also called glycerol trinitrate) ointment directly to the internal sphincter. Nitro-glycerine rectal ointment is approved by the US Food and Drug Administration (FDA) for moderate-to-severe pain associated with anal fissures and may be considered when conservative therapies have failed.

The short gastric arteries branch from the splenic artery near the splenic hilum to travel back in the gastrosplenic ligament to supply the fundus of the stomach. Therefore, these may be injured in this case.
The splenic artery courses deep to the stomach to reach the hilum of the spleen. It doesn’t travel in the gastrosplenic ligament although it does give off branches that do.
The middle colic artery is a branch of the superior mesenteric artery that supplies the transverse colon.
Gastroepiploic artery is the largest branch of the splenic artery that courses between the layers of the greater omentum to anastomose with the right gastroepiploic.
Left gastric artery, a branch of the coeliac trunk. It supplies the left half of the lesser curvature.

The AV node is a conducting tissue found between the atria and the ventricles of the heart. It conducts electrical signal from the atria to the ventricles and acts a delaying mechanism preventing the atria and the ventricles from contracting at the same time. This decremental conduction prevents premature ventricular contraction in cases such as atrial fibrillation. A delay in the AV node is the reason for the PR segment seen on the ECG. In certain types of supraventricular tachycardia, a person could have two AV nodes; this will cause a loop in electrical current and uncontrollably rapid heart beat. When this electricity catches up with itself, it will dissipate and return to a normal heart rate.

Perforins are characteristically found In the granules of CD8+ T cells and natural killer cells. They are cytolytic proteins that insert into the target plasma membrane forming a hole and resulting in lysis. They along with granzyme B induce apoptosis in the target cell.

The most likely diagnosis is aortic dissection.

Aortic dissection occurs following a tear in the aortic intima with subsequent separation of the tissue within the weakened media by the propagation of blood. There are four different classifications of aortic dissection and the commonest one used is the Stanford classification dividing them into type A and type B. A type A dissection involves the ascending aorta and/or the arch whilst type B dissection involves only the descending aorta and occurs distal to the origin of the left subclavian artery.

Aortic dissection in pregnancy occurs most commonly in the third trimester due to the hyperdynamic state and hormonal effect on vasculature. Other common predisposing factors for aortic dissection include Marfans syndrome, Ehlers-Danlos syndrome, and bicuspid aortic valve. Aortic dissection often presents with sudden severe, tearing chest pain, vomiting, and syncope, most often from acute pericardial tamponade. The patient may be hypertensive, clinically. The right coronary artery may become involved in the dissection, causing myocardial infarct in up to 2% of the cases (hence ST-segment elevation in the inferior leads). An aortic regurgitant murmur may be auscultated.

The management options during pregnancy include:
1. <28 weeks of gestation: aortic repair with the foetus kept in utero
2. 28–32 weeks of gestation: dependent on foetal condition
3. >32 weeks of gestation: caesarean section followed by aortic repair in the same operation

Total parenteral nutrition (TPN), is the practice of feeding a person intravenously, circumventing the gut. It is normally used in the following situations: surgery, when feeding by mouth is not possible, when a person’s digestive system cannot absorb nutrients due to chronic disease or if a person’s nutrient requirement cannot be met by enteral feeding and supplementation. A sterile bag of nutrient solution, between 500 ml and 4L, is provided. The pump infuses a small amount (0.1–10 ml/h) continuously to keep the vein open. The nutrient solution consists of water, glucose, salts, amino acids, vitamins and sometimes emulsified fats. Ideally each patient is assessed individually before commencing on parenteral nutrition, and a team consisting of doctors, nurses, clinical pharmacists and dietitians evaluate the patient’s individual data and decide what formula to use and at what rate.

Mithramycin or Plicamycin is a tricyclic pentaglycosidic antibiotic derived from Streptomyces strains. It inhibits RNA and protein synthesis by adhering to DNA. It is used as a fluorescent dye and as an antineoplastic agent. It is also used to reduce hypercalcaemia, especially caused by malignancy. Plicamycin is currently used in multiple areas of research, including cancer cell apoptosis and as a metastasis inhibitor.

In a radical nephrectomy, the surgeon removes the whole kidney, the fatty tissues surrounding the kidney and a portion of the tube connecting the kidney to the bladder (ureter). The surgeon may remove the adrenal gland that sits atop the kidney if a tumour is close to or involves the adrenal gland. Radical nephrectomy is the treatment of choice for localized renal cell carcinoma (RCC). Biopsy should not be performed when a nephrectomy is planned but is mandatory before any ablative therapies are undertaken.

Renal cell carcinoma comprise up to 85% of all renal malignancies. Males are more commonly affected than females and sporadic tumours typically affect patients in their sixth decade.

Burn depth is classified as first, second, third, or fourth degree, as follows:
First-degree burns are usually red, dry, and painful. Burns initially termed first-degree are often actually superficial second-degree burns, with sloughing occurring the next day.
Second-degree burns are often red, wet, and very painful. Their depth, ability to heal, and propensity to form hypertrophic scars vary enormously.
Third-degree burns are generally leathery in consistency, dry, insensate, and waxy. These wounds will not heal, except by contraction and limited epithelial migration, with resulting hypertrophic and unstable cover. Burn blisters can overlie both second- and third-degree burns. The management of burn blisters remains controversial, yet intact blisters help greatly with pain control. Debride blisters if infection occurs.
Fourth-degree burns involve underlying subcutaneous tissue, tendon, or bone. Usually, even an experienced examiner has difficulty accurately determining burn depth during an early examination. As a general rule, burn depth is underestimated upon initial examination.

The management plan for patients with large burns that require inpatient care is usually determined by the physiology of the burn injury.
Hospitalization is divided into 4 general phases, including (1) initial evaluation and resuscitation, (2) initial wound excision and biologic closure, (3) definitive wound closure, and (4) rehabilitation and reconstruction.

Early excision and closure of full-thickness wounds change the natural history of burn injury, avoiding the otherwise common occurrence of wound sepsis. Wound size is the most important factor in determining the need for early operation

Medications
See the list below:
– Silver sulfadiazine – Broad antibacterial spectrum; painless application
– Aqueous 0.5% silver nitrate – Broad-spectrum coverage, including fungi; leeches electrolytes
– Mafenide acetate – Broad antibacterial spectrum; penetrates eschar best
– Petrolatum – Bland and nontoxic
– Various debriding enzymes – Useful in selected partial-thickness wounds
– Various antibiotic ointments – Useful in many superficial partial-thickness wounds
Membranes
See the list below:
– Porcine xenograft – Adheres to wound coagulum and provides excellent pain control
– Split-thickness allograft – Vascularizes and provides durable temporary closure of wounds
– Various hydrocolloid dressings – Provide vapour and bacteria barrier while absorbing wound exudate
– Various impregnated gauzes – Provide vapour and bacteria barrier while allowing drainage
– Various semipermeable membranes – Provide vapour and bacteria barrier
– Acticoat (Westhaim Biomedical, Saskatchewan, Canada) – Nonadherent wound dressing that delivers a low concentration of silver for antisepsis
– Biobrane (Dow-Hickman, Sugarland, Tex) – Synthetic bilaminate that facilitates fibrovascular tissue growth into the inner layer and provides temporary vapour and bacteria barrier
– Transcyte (Smith and Nephew, Largo, Fla) – Synthetic bilaminate that facilitates fibrovascular tissue growth into the inner layer populated with allogenic fibroblasts and overlying layer that provides temporary vapour and bacteria barrier
– AlloDerm R – Consists of cell-free allogenic human dermis; requires an immediate thin overlying autograft
– Integra R – Provides scaffold for neodermis; requires delayed thin autograft

Endocervical polyps or microglandular hyperplasia are benign growths occurring in the endocervical canal, in about 2-5% women and occur secondary to use of oral contraceptives. They are usually < 1cm in size, friable and reddish-pink. Usually asymptomatic, they can cause bleeding or become infected, leading to leucorrhoea (purulent vaginal discharge). They are usually benign but need to be differentiated from adenocarcinomas by histology.

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.

The pterygomandibular raphé (pterygomandibular ligament) provides attachment on its posterior border to the superior pharyngeal constrictor and on its anterior border to the buccinator muscle.

Type I hypersensitivity reaction is an immediate reaction that occurs due to binding of the antigen with antibodies attached to mast cells in a previously sensitized person. It has an immediate phase, which is characterised by vasodilation, leakage of plasma, smooth muscle spasm, or glandular secretions. This manifests in about 5-30 min and usually resolves within 60 mins. The delayed phase follows after 24 hours and can persist up to several days. It is due to infiltration of eosinophils, neutrophils, basophils and CD4+ cells and leads to tissue destruction. The nature of the reaction varies according to the site. It can take the form of skin allergy, hives, allergic rhinitis, conjunctivitis, bronchial asthma or food allergy.

Worldwide, approximately 500,000 new cases of cervical cancer and 274,000 deaths are attributable to cervical cancer yearly. This makes cervical cancer the second most common cause of death from cancer in women. The mainstay of cervical cancer screening has been the Papanicolaou test (Pap smear).

Acute transfusion reactions present as adverse signs or symptoms during or within 24 hours of a blood transfusion. The most frequent reactions are fever, chills, pruritus, or urticaria, which typically resolve promptly without specific treatment or complications.