Absence of comorbidities and a small procedure with no likelihood of systemic compromise will equate to an ASA score of 1.

The ASA physical status classification system is a system for assessing the fitness of patients before surgery. It has six grades, as described below:

ASA 1: No physiological, biochemical, or psychiatric disturbance. The surgical pathology is localised and has not invoked systemic disturbance.

ASA 2: Mild or moderate systemic disruption caused either by the surgical disease process or through an underlying pre-existing disease.

ASA 3: Severe systemic disruption, not life-threatening, caused either by the surgical pathology or a pre-existing disease.

ASA 4: Patient has severe systemic disease that is a constant threat to life.

ASA 5: Patient is moribund and will not survive without surgery.

ASA 6: A brain-dead patient whose organs are being removed with the intention of transplanting them into another patient.

Juvenile polyps are benign hamartomas with neoplastic potential that are the most frequent gastrointestinal polyp of childhood, with the peak incidence between 3 and 5 years of age.. The presence of multiple juvenile polyps may indicate a premalignant condition commonly named juvenile polyposis coli or juvenile polyposis syndrome (JPS). In contrast, single or solitary juvenile polyps generally are considered benign sporadic lesions that confer little to no future risk of malignancy. Most frequent presentation is painless rectal bleeding. Other features include a prolapsing rectal mass and abdominal pain.

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.

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.

Driving pressure is the difference between inflow and outflow pressure. For the pulmonary circulation, this is the difference between pulmonary arterial (pa) and left atrial pressure (pLA). Normally, mean driving pressure is about 10 mmHg, computed by subtracting pLA (5 mmHg) from pA (15 mmHg). This is in contrast to a mean driving pressure of nearly 100 mmHg in the systemic circulation.

Plasma cell are memory cells. After the antigen Is engulfed by the B cells it is presented to the CD4+ helper cells via the MCH II receptor and this leads to their activation which in turn stimulates the B cells to form antibodies against that specific antigen. Some B cells differentiate into plasma cells also called memory cells that get activated after subsequent infection.

Lymphadenopathy is common in children and is usually reactive in nature. The description fits that of a benign, reactive lymph node.

Absorption of vitamin B12 is by an active transport process and occurs in the ileum. Most cobalamins are bound to proteins and are released in the stomach due to low pH and pepsin. The cobalamins then bind to R proteins, i.e. haptocorrin (HC) secreted from salivary glands and gastric juice. Another cobalamin binding protein is Intrinsic factor (IF) secreted from the gastric parietal cells. The cobalamin-HC complex is digested by pancreatic proteases in the intestinal lumen, and the free cobalamin then binds to IF. The complex then reaches a transmembrane receptor in the ileum and undergoes endocytosis. Cobalamin is then released intracellularly and binds to transcobalamin II (TC II). The newly formed complex then exits the ileal cell and enters the blood circulation.

Primary haemostatic control means the first line of defence against immediate bleeding. This is carried out by the platelets. They immediately form a haemostatic plug at the site of injury. Coagulation starts within 20s after an injury to the blood vessel which damage the endothelial cells. Secondary haemostasis follows which includes activation of the coagulation factors to form fibrin strands which mesh together forming the platelet plug. Platelets interact with platelet collagen receptor, glycoprotein Ia/IIa and to collagen fibres in the vascular endothelium. This adhesion is mediated by von Willebrand factor (vWF), which forms links between the platelet glycoprotein Ib/IX/V and collagen fibrils. The platelets are then activated and release the contents of their granules into the plasma, in turn activating other platelets and white blood cells.

The patient mostly has an appendicular mass.
At present, the treatment of choice for uncomplicated acute appendicitis in adults continues to be surgical. The inflammation in acute appendicitis may sometimes be enclosed by the patient’s own defence mechanisms, by the formation of an inflammatory phlegmon or a circumscribed abscess. The management of these patients is controversial. An immediate appendectomy may be technically demanding. The exploration often ends up in an ileocecal resection or a right-sided hemicolectomy. Recently, the conditions for conservative management of these patients have changed due to the development of computed tomography and ultrasound, which has improved the diagnosis of enclosed inflammation and made drainage of intra-abdominal abscesses easier. New efficient antibiotics have also given new opportunities for nonsurgical treatment of complicated appendicitis. The traditional management of these patients is nonsurgical treatment followed by interval appendectomy to prevent a recurrence. The need for interval appendectomy after successful nonsurgical treatment has recently been questioned because the risk of recurrence is relatively small.
In patients with suspicion of contained appendiceal inflammation, based on a palpable mass or long duration of symptoms, the diagnosis should be confirmed by imaging techniques, especially CT scan. The patient should receive primary nonsurgical treatment with antibiotics and abscess drainage as needed. After successful nonsurgical treatment, no interval appendectomy is indicated in some cases, but the patient should be informed about the risk of recurrence especially in the presence of appendicolith. The risk of missing another underlying condition (cancer or CD) is low, but motivates a follow-up with a colon examination and/or a CT scan or US, especially in patients above the age of 40 years.

Serine protease coagulation factors include: thrombin, plasmin, Factors X, XI and XII. Factor VIII and factor V are glycoproteins and factor XIII is a transglutaminase.

The distinction between a benign renal adenoma and renal adenocarcinoma is commonly made on the basis of size. Tumours less than 2 cm in size rarely become malignant as opposed to those greater than 3 cm.

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.

Rapid eye movement (REM) sleep is also known as paradoxical sleep, as the summed activity of the brain’s neurons is quite similar to that during waking hours. Characterised by rapid movements of the eyes, most of the vividly recalled dreams occur during this stage of sleep. The total time of REM sleep for an adult is about 90–120 min per night.
Certain neurones in the brainstem, known as REM sleep-on cells, which are located in the pontine tegmentum, are particularly active during REM sleep and are probably responsible for its occurrence. The eye movements associated with REM are generated by the pontine nucleus with projections to the superior colliculus and are associated with PGO (pons, geniculate, occipital) waves.

Pneumothorax is the most common complication of a fine-needle aspiration procedure. Various factors, such as lesion size, have been associated with increased risk of pneumothorax .

Mastectomy should ideally be done in this patient. This patient has extensive spread of disease and tumour margins are unclear which makes radiotherapy the less likely option. Mastectomy is the safest option in this scenario. Patients who have undergone mastectomy may be offered a reconstructive procedure either in conjunction with their primary resection or as a staged procedure at a later date.

An autoimmune disease, primary biliary cirrhosis results in destruction of intrahepatic bile ducts. This leads to cholestasis, cirrhosis and eventually, hepatic failure. Symptoms includes fatigue, pruritus and steatorrhea. Increased IgM levels, along with antimitochondrial antibodies are seen in the serum. Liver biopsy is diagnostic, and also aids in staging of disease.

A week following a MI attack, a little collagen starts to form and deposit. By the end of the 2nd week, neovascularisation of the scar occurs, with some collagen being laid down in a haphazard fashion. By this time the scar attains some strength. During the next 6 months, collagen is constantly being laid down and is rearranged in order to shrink the scar. Most of the blood vessels by this time have regenerated, decreasing vascularity of the scar reaching full maturity.

Rh disease is also known as erythroblastosis fetalis and is a disease of the new-born. In mild states it can cause anaemia with reticulocytosis and in severe forms causes severe anaemia, morbus hemolytcus new-born and hydrops fetalis. RBCs of the Rh+ baby can cross the placenta and enter into the maternal blood. As she is Rh- her body will form antibodies against the D antigen which will pass through the placenta in subsequent pregnancies.

CLL or chronic lymphocytic leukaemia is the most common leukaemia seen in the Western world. Twice more common in men than women, the incidence of CLL increases with age. About 75% cases are seen in patients aged more than 60 years. The blood, marrow, spleen and lymph nodes all undergo infiltration, eventually leading to haematopoiesis (anaemia, neutropenia, thrombocytopenia), hepatomegaly, splenomegaly and decreased production of immunoglobulin. In 98% cases, CD+5 B cells undergo malignant transformation.
Often diagnosed on blood tests while being evaluated for lymphadenopathy, CLL causes symptoms like fatigue, anorexia, weight loss, pallor, dyspnoea on exertion, abdominal fullness or distension. Findings include multiple lymphadenopathy with minimal-to- moderate hepatomegaly and splenomegaly. Increased susceptibility to infections is seen. Herpes Zoster is common. Diffuse or maculopapular skin infiltration can also be seen in T-cell CLL.
Diagnosis is by examination of peripheral blood smear and marrow: hallmark being a sustained, absolute leucocytosis (>5 ×109/l) and increased lymphocytes in the marrow (>30%). Other findings can include hypogammaglobulinemia (<15% of cases) and, rarely, raised lactate dehydrogenase (LDH). Only 10% cases demonstrate moderate anaemia and/or thrombocytopenia.

Peyronie’s disease leads to development of fibrous plaques in the penile soft tissue and occurs in 1% of men, most commonly affecting white males above 40 years age. It is a connective tissue disorder named after a French surgeon, François de la Peyronie who first described it. Symptoms include pain, hard lesions on the penis, abnormal curvature of erect penis, narrowing/shortening, painful sexual intercourse and in later stages, erectile dysfunction. 30% cases report fibrosis in other elastic tissues such as Dupuytren’s contractures of the hand. There is likely a genetic predisposition as increased incidence is noted among the male relatives of an affected individual.

An anal fistula is an abnormal tract between the anal canal and the skin around the anus.
Anal fistulas can be classified according to their relationship with the external sphincter. A fistula may be complex, with several openings onto the perianal skin. Intersphincteric fistulas are the most common type and cross only the internal anal sphincter. Trans-sphincteric fistulas pass through both the internal and external sphincters.

The aim is to drain the infected material and encourage healing.
For simple intersphincteric and low trans-sphincteric anal fistulas, the most common treatment is a fistulotomy or laying open of the fistula tract.
For high and complex (deeper) fistulas that involve more muscle, with a high risk of faecal incontinence or recurrence, surgery aims to treat the fistula and preserve sphincter-muscle function. Techniques include a 1‑stage or 2‑stage seton (suture material or rubber sling) either alone or in combination with fistulotomy, ligation of an intersphincteric fistula tract, creating a mucosal advancement flap, injecting glue or paste, or inserting a fistula plug .

Pre-existing chronic autoimmune (Hashimoto’s) thyroiditis is the only known risk factor for primary thyroid lymphoma and is present in approximately one-half of patients. Among patients with Hashimoto’s thyroiditis, the risk of thyroid lymphoma is at least 60 times higher than in patients without thyroiditis.

Total peripheral resistance = Mean arterial pressure/Cardiac output. And the mean arterial pressure = Diastolic pressure + 1/3 (Systolic pressure – Diastolic pressure), i.e., 70 + 1/3 (130-70) = 90 mmHg. Therefore, total peripheral resistance = 90 mmHg/5 l per min = 18 mmHg × min/l.

The American Society of Colon and Rectal Surgeons (ASCRS) states that clinicians should typically offer haemorrhoidectomy to patients with symptomatic disease from external haemorrhoids or combined internal/external haemorrhoids with prolapse. For those who undergo surgical haemorrhoidectomy, a multimodality pain regimen is recommended to reduce use of narcotics and promote a faster recovery.

The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman’s capsule to the loop of Henle. It is conventionally divided into the proximal convoluted tubule (PCT) and the proximal straight tubule (PST). The proximal tubule reabsorbs the majority (about two-thirds) of filtered salt and water. This is done in an essentially iso-osmotic manner. Both the luminal salt concentration and the luminal osmolality remain constant (and equal to plasma values) along the entire length of the proximal tubule. Water and salt are reabsorbed proportionally because the water is dependent on and coupled with the active reabsorption of Na+. The water permeability of the proximal tubule is high and therefore a significant transepithelial osmotic gradient is not possible.

Sjogren syndrome (SS) is a long-term autoimmune disease that affects the body’s moisture-producing glands. Primary symptoms are a dry mouth and dry eyes. Other symptoms can include dry skin, vaginal dryness, a chronic cough, numbness in the arms and legs, feeling tired, muscle and joint pains, and thyroid problems. Those affected are at an increased risk (5%) of lymphoma. It primarily affects women in their peri and post-menopausal years of life.

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.

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.

An Anal fissure is a cut or a tear in the anal canal typically caused by passing a hard stool. Patients often complain of severe anal pain and bleeding with bowel movements. On physical examination, you may see the fissure or just the sentinel tag. If the examination appears normal, you can elicit point tenderness. We recommend against continuing the digital rectal examination or anoscopy if the patient is having pain during the examination.
The primary goals of therapy are to properly bulk the stool with adequate fibre and relax the anal muscle. Specific steps include the following:
Properly bulk the stool with adequate fibre to minimize constipation and diarrhoea; both frequent bowel movements and hard bowel movements can lead to an anal fissure.
Temporary use of laxatives such as daily Miralax or senna. The dose of Miralax can be titrated up or down to achieve desired results. As the patient’s fibre supplementation increases, the need for Miralax will diminish.
Chronic use of laxatives should be avoided because it can lead to worsening colonic function and constipation.
Diltiazem 2% ointment is to be placed on the anal muscle 3 times daily—continue for a minimum of 8 weeks, even if symptoms improve earlier.
If a patient cannot tolerate diltiazem or is breastfeeding or pregnant, 0.2% nitroglycerin-compounded ointment can be prescribed. However, the proper dose of nitroglycerin is important as too high of a dose can cause severe headaches.
Do NOT prescribe haemorrhoid ointments or suppositories, especially steroid-based ones. Steroid ointments do not help. They do cause perianal skin thinning and dermatitis. At best, they act as a placebo, but they often are used chronically and cause unpleasant perianal skin changes.
Use mental anal muscle relaxation: Actively thinking about relaxing sphincter tone.
Consider sitz baths: Soaking the anal area in warm water induces relaxation. Warmer water induces more relaxation. No additives are needed.
Surgical intervention (such as Botox injections or sphincterotomy) is considered for patients whose symptoms do not improve with the above management strategies. It is imperative that the patient increases fibre and water intake so bowel movements are very soft before the surgical intervention to maximize chances of postoperative healing.