In performing noncardiac surgery on patients on anticoagulation, the major concern is when it is safe to perform surgery without increasing the risk of haemorrhage or increasing the risk of thromboembolism (e.g., venous, arterial) after discontinuing treatment.
Any patient who is on long-term anticoagulation and is to undergo a major surgery needs proactive management.
Heparin is discontinued 6-12 hours before surgery and restarted at 200-400 U/h at 4-6 hours after surgery. Coumadin is restarted as soon as tolerated by the patient. Stop oral anticoagulants at least 5 days preoperatively, and do not perform the procedure until the PT is in the reference range.

Answer: Kruskall Wallis test

Kruskall Wallis test is a non-parametric method for testing whether samples originate from the same distribution. It is used for comparing two or more independent samples of equal or different sample sizes. It extends the Mann–Whitney U test, which is used for comparing only two groups. The parametric equivalent of the Kruskal–Wallis test is the one-way analysis of variance (ANOVA).
T-tests are useful for comparing the means of two samples. There are two types: paired and unpaired.

Paired means that both samples consist of the same test subjects. A paired t-test is equivalent to a one-sample t-test.

Unpaired means that both samples consist of distinct test subjects. An unpaired t-test is equivalent to a two-sample t-test.
A chi-squared test, also written as χ2 test, is any statistical hypothesis test where the sampling distribution of the test statistic is a chi-squared distribution when the null hypothesis is true. The chi-squared test is used to determine whether there is a significant difference between the expected frequencies and the observed frequencies in one or more categories.

Fisher’s exact test is a statistical test used to determine if there are non-random associations between two categorical variables.

Bowel preparation is a significant aspect of the flexible sigmoidoscopy procedure. Clear visibility of the bowel mucosa is critical for a thorough examination. The combination of a light breakfast in the morning and the application of 1 or 2 phosphate enemas a few hours before the examination is a safe and commonly used method of preparing a patient for a flexible sigmoidoscopy procedure.

With a constant blood flow to a given tissue bed, there will be an increase in oxygen extraction by the tissue with the following; an increase in tissue metabolism and oxygen requirements: warming (or fever), exercise, catecholamines and thyroxine. With cooling, the demand for oxygen decreases, leading to decreased oxygen extraction.

Staphylococcus aureus is the most pathogenic species and is implicated in a variety of infections.  S. aureus can be identified due to its production of coagulase. The staphylococcal enzyme coagulase will cause inoculated citrated rabbit plasma to gel or coagulate. The coagulase converts soluble fibrinogen in the plasma into insoluble fibrin.

Dopamine acts as a neurotransmitter in the brain, activating dopamine receptors. It is also a neurohormone released from the hypothalamus. It plays an important role in the reward system. It is believed that dopamine provides a teaching signal to parts of the brain responsible for acquiring new motor sequences (behaviours), by activation of dopamine neurons when an unexpected reward is presented. Loss of dopamine neurones in the nigrostriatal pathway causes Parkinson’s disease. In the frontal lobes, dopamine controls the flow of information from other areas of the brain, and thus, dopamine disorders in this region can cause a decline in neurocognitive functions, especially memory, attention and problem solving. Reduced dopamine concentrations in the prefrontal cortex are thought to contribute to attention-deficit disorder and some symptoms of schizophrenia. Dopamine is also the primary neuroendocrine regulator of the secretion of prolactin from the anterior pituitary gland. Dopamine is also commonly associated with the pleasure system of the brain. This plays a key role in understanding the mechanism of action of drugs (such as cocaine and the amphetamines), which seem to be directly or indirectly related to the increase of dopamine.

The anterior talofibular ligament passes from the anterior margin of the fibular malleolus. It is the most commonly injured ligament, as part of the lateral ligament of the ankle.

Recurrent bacterial infections may be due to lack of B-cell function, consequently resulting in a lack of gamma globulins production. Once the maternal antibodies have depleted, the disease manifests with greater severity and is called x-linked agammaglobulinemia also known as ‘X-linked hypogammaglobulinemia’, ‘XLA’ or ‘Bruton-type agammaglobulinemia. it is a rare x linked genetic disorder that compromises the bodies ability to fight infections.
Acute leukaemia causes immunodeficiency but not so specific.
DiGeorge syndrome is due to lack of T cell function.
Aplastic anaemia and EBV infection does not cause immunodeficiency.

Osteoid osteoma, which tends to affect young adults, can occur in any bone but is most common in long bones. It can cause pain (usually worse at night) that is typically relieved by mild analgesics, such as non-steroidal anti-inflammatory drugs. X-ray findings include a small radiolucent zone surrounded by a larger sclerotic zone.

The forces of elastance (compliance), frictional resistance and inertia have been identified as the forces that oppose lung inflation and deflation. The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. About 60–66% of the total work performed by the respiratory muscles is used to overcome the elastic or compliance characteristics of the lung–chest cage, 30–35% is used to overcome frictional resistance and only 2–5% of the work is used for inertia.

On transmission of a loud sound into the central nervous system, an attenuation reflex occurs after a latent period of 40-80 ms. This reflex contracts the two muscles that pull malleus and stapes closer, developing a high degree of rigidity in the entire ossicular chain. This reduces the ossicular conduction of low frequency sounds to the cochlea by 30-40 decibels. In this way, the cochlea is protected from damage due to loud sounds (these are low frequency sounds) when they develop slowly.

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.

Crohn’s disease is a chronic, inflammatory disease that can affect any part of the gastrointestinal tract but is usually seen in the distal ileum and colon. It is transmural and symptoms include chronic diarrhoea, abdominal pain, fever, anorexia and weight loss. On examination, there is usually abdominal tenderness with a palpable mass or fullness seen occasionally. Rectal bleeding is uncommon (except in isolated colonic involvement) which manifests like ulcerative colitis. Differential diagnosis includes acute appendicitis or intestinal obstruction. 25%-33% patients also have perianal disease in the form of fissure or fistulas.
Extra intestinal manifestations predominate in children, and include: arthritis, pyrexia, anaemia or growth retardation. Histologically, the disease shows crypt inflammation and abscesses initially, which progress to aphthoid ulcers. These eventually develop into longitudinal and transverse ulcers with interspersed mucosal oedema, leading to the characteristic ‘cobblestoned appearance’. Transmural involvement leads to lymphoedema and thickening of bowel wall and mesentery, leading to extension of mesenteric fat on the serosal surface of bowel and enlargement of mesenteric nodes. There can also be hypertrophy of the muscularis mucosae, fibrosis and stricture formation, which can cause bowel obstruction. Abscesses are common and the disease can also leas to development of fistulas with various other organs, anterior abdominal wall and adjacent muscles. Pathognomonic non-caseating granulomas are seen in 50% cases and they can occur in nodes, peritoneum, liver, and in all layers of the bowel wall. The clinical course does not depend on the presence of granulomas. There is sharp demarcation between the diseased and the normal bowel (skip areas).
35% cases show only the ileal involvement, whereas in 45% cases, both the ileum and colon are involved with a predilection for right side of colon. 20% cases show only colonic involvement, often sparing the rectum (unlike ulcerative colitis). In occasional cases, there is jejunoileitis – involvement of the entire small bowel. The stomach, duodenum and oesophagus are rarely involved, although there has been microscopic evidence of disease involving the gastric antrum in younger patients. The affected small bowel segments show increased rick of cancer. Moreover, patients with colonic disease show a long-term risk of cancer similar to that seen in ulcerative colitis.

The presence of a necrotic and infected forefoot with necrosis of the heel and a boggy indurated swelling anterior to the ankle joint in a patient with sepsis secondary to diabetic foot ulcer indicates that a below knee amputation is the best option.

Based on Wagner’s Classification of Diabetic Foot Ulcers, this patient has a grade of 5 where there is gangrene or necrosis of large portion of the foot
requiring major limb amputation.

Infection in a diabetic foot is usually secondary to ulceration. Rarely, infection itself causes ulceration. It can either be local or systemic. Treatment requires early incision and drainage or debridement and empirical broad-spectrum antibiotic therapy. If there is co-exiting gangrene or extensive tissue loss, early amputation at the appropriate level should be considered to remove the focus of infection.

Open right hemicolectomy (open right colectomy) is a procedure that involves removing the caecum, the ascending colon, the hepatic flexure (where the ascending colon joins the transverse colon), the first third of the transverse colon, and part of the terminal ileum, along with fat and lymph nodes. It is the standard surgical treatment for malignant neoplasms of the right colon; the effectiveness of other techniques are measured by the effectiveness of this technique.

The caecum is a short, pouch-like region of the large intestine between the ascending colon and vermiform appendix. It is located in the lower right quadrant of the abdominal cavity, inferior and lateral to the ileum.

Proctalgia fugax (PF) is a benign painful rectal condition that is defined as intermittent, recurring, and self-limiting pain in the anorectal region in the absence of organic pathology. The pain of proctalgia fugax is sharp or gripping and severe. Similar to other urogenital focal pain syndromes, such as vulvodynia and proctodynia, the causes remain obscure. Stress and sitting for prolonged periods often increase the frequency and intensity of attacks of proctalgia fugax. Patients often feel an urge to defecate with the onset of the paroxysms of pain . Depression often accompanies the pain of proctalgia fugax but is not thought to be the primary cause. The symptoms of proctalgia fugax can be so severe as to limit the patient’s ability to perform activities of daily living. Reassurance has proven to help in many cases as the condition has been linked to stress.

The optic foramen is the opening to the optic canal. The canal is located in the sphenoid bone; it is bounded medially by the body of the sphenoid and laterally by the lesser wing of the sphenoid. The superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove). The groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery into the orbital cavity. Compared to the optic nerve, the ophthalmic artery is located inferolaterally within the canal.

The fourth ventricle, is a cavity of the brains ventricular system in which the cerebrospinal fluid is formed. This cavity is located behind the pons and upper half of the medulla oblongata. It extends from the cerebral aqueduct, to its connection to the third ventricle, and to the obex- which is the caudal tip of the fourth ventricle. The floor of the fourth ventricle consists of three parts – superior, intermediate and inferior. This inferior aspect of the floor of the fourth ventricle has the nucleus of the abducens nerve, CN VI which is looped over by the facial nerve.

Gout is a rheumatic disease caused by the precipitation of monosodium urate crystals into tissues, usually joints. This causes acute or chronic pain; the acute illness initially affects only one joint, often the first metatarsophalangeal joint. The diagnosis of the disease requires the identification of crystal in the synovial fluid. These crystals are needle-shaped and strongly negatively birefringent.

The seminal vesicles are two lobulated membranous pouches situated between the fundus of the bladder and rectum and act as a reservoir for the semen and secrete a fluid that is added to the seminal fluid. Each sac is pyramidal in shape but they all vary in size not only in different individuals but also in the same individuals. The anterior surface is in contact with the fundus of the bladder, extending from near the termination of the ureter to the base of the prostate. Each vesicle consist of single tube, which gives off several irregular caecal diverticula. These separate coils and the diverticula are connected by fibrous tissue.