The collection of abnormalities found in these patients is referred to as a hyposplenic film.The following features can be seen on hyposplenic blood films:Howell-Jolly bodiesHeinz’s bodiesTarget cellsRBCs with nuclei on occasionLymphocytosisMacrocytosisAcanthocytesTeardrop cells, also known as dacrocytes, are named for their teardrop-shaped shape. Dacrocytosis is a condition in which a large number of these cells are present. Myelofibrosis and beta thalassemia major both have dacrocytes, but hyposplenism does not.

Antibiotics that are bactericidal kill bacteria, while antibiotics that are bacteriostatic limit their growth or reproduction. The antibiotics grouped into these two classes are summarized in the table below:Bactericidal antibioticsBacteriostatic antibioticsVancomycinMetronidazoleFluoroquinolone, such as ciprofloxacinPenicillins, such as benzylpenicillinCephalosporin, such as ceftriaxoneCo-trimoxazoleTetracyclines, such as doxycyclineMacrolides, such as erythromycinSulphonamides, such as sulfamethoxazoleClindamycinTrimethoprimChloramphenicol

Rubella can be contagious from 7 days before to 7 days after the rash appears.Patients with measles are contagious from 1-2 days before the onset of symptoms.A person with chickenpox is considered contagious beginning 1 to 2 days before rash onset until all the chickenpox lesions have crusted (scabbed). The infectious period of mumps is considered from 2 days before to 5 days after parotitis onset.Hepatitis A is highly transmissible and has an average incubation period of 28 to 30 days (range 15–50 days). The maximum infectivity is during the second half of the incubation period (i.e. while asymptomatic) and most cases are considered non-infectious after the first week of jaundice.

De Quervain tenosynovitis is named after the Swiss surgeon, Fritz de Quervain, who first described it in 1895. It is a condition which involves tendon entrapment affecting the first dorsal compartment of the wrist. With this condition thickening of the tendon sheaths around the abductor pollicis longus and extensor pollicis brevis develops where the tendons pass in through the fibro-osseous tunnel located along the radial styloid at the distal wrist. Pain is exacerbated by thumb movement and radial and ulnar deviation of the wrist.The estimated prevalence of de Quervain tenosynovitis is about 0.5% in men and 1.3% in women with peak prevalence among those in their forties and fifties. It may be seen more commonly in individuals with a history of medial or lateral epicondylitis. Bilateral involvement is often reported in new mothers or child care providers in whom spontaneous resolution typically occurs once lifting of the child is less frequent.

Meta-analysis is a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research. Outcomes from a meta-analysis may include a more precise estimate of the effect of treatment or risk factor for disease, or other outcomes, than any individual study contributing to the pooled analysis. The examination of variability or heterogeneity in study results is also a critical outcome.The benefits of meta-analysis include a consolidated and quantitative review of a large, and often complex, sometimes apparently conflicting, body of literature. The specification of the outcome and hypotheses that are tested is critical to the conduct of meta-analyses, as is a sensitive literature search.Important medical questions are typically studied more than once, often by different research teams in different locations. In many instances, the results of these multiple small studies of an issue are diverse and conflicting, which makes the clinical decision-making difficult. The need to arrive at decisions affecting clinical practise fostered the momentum toward evidence-based medicine. Evidence-based medicine may be defined as the systematic, quantitative, preferentially experimental approach to obtaining and using medical information. Therefore, meta-analysis, a statistical procedure that integrates the results of several independent studies, plays a central role in evidence-based medicine.

Cardiac output (CO) is calculated by multiplying stroke volume (SV) by heart rate (HR):CO = HR x SVAs a result, both stroke volume and heart rate are exactly proportional to cardiac output. There will be an increase in cardiac output if the stroke volume or heart rate increases, and a reduction in cardiac output if the stroke volume or heart rate lowers.

The use of a beta-blocker at the same time increases the risk of myocardial depression, but it is not a contraindication.The use of adenosine is contraindicated in the following situations:AsthmaCOPD (chronic obstructive pulmonary disease)Decompensated heart failure Long QT syndromeAV block in the second or third degreeSinusitis is a condition in which the sinuses become (unless pacemaker fitted)Hypotension that is severe

Phenytoin Contraindications include:HypersensitivitySinus bradycardiaSinoatrial blockSecond and third degree A-V blockAdams-Stokes syndromeConcurrent use with delavirdineHistory of prior acute hepatotoxicity attributable to phenytoin

Inflammation can be divided intoacute inflammation, which occurs over seconds, minutes, hours, and days, andchronic inflammation, which occurs over longer periods.Acute inflammationcommences within seconds or minutes following the injury of tissues. There are numerous potential stimuli for an acute inflammatory response including infections (bacterial, viral, fungal, parasitic), tissue necrosis, foreign bodies, and Immune reactions (hypersensitivity reactions). The chief cell type of acute inflammation is the neutrophil.There are three main processesthat occur in the acute inflammatory response:Increased blood flowIncreased capillary permeabilityNeutrophil migration1. Increased blood flow:Vasoactive mediators are released, such as nitric oxide, histamine, bradykinins, and prostaglandin E2. These mediators cause vasodilatation and increased blood flow to the area (causing redness and heat).2. Increased capillary permeability:The vasoactive mediators also cause increased capillary permeability by causing endothelial cell contraction that widens the intercellular gaps of venules. This allows an outpouring of protein-rich fluid (exudate) into the extracellular tissues that results in a reduction of intravascular osmotic pressure and an increase in extravascular/interstitial pressure. The increased interstitial osmotic pressure leads to oedema.3. Neutrophil migration:Neutrophils leave the vasculature through the following sequence of events:Margination and rolling: neutrophils flow nearer the vessel wall, rather than in the axial stream, which is referred to as margination. Following margination the neutrophils begin rolling along the surface of the vascular endothelium.Activation and adhesion: then as a result of interaction with endothelial cell adhesion molecules (CAMs) that is mediated by selectins, the neutrophils are activated and adhere to the endothelium.Transmigration: once bound to the endothelium, neutrophils squeeze through gaps between adjacent endothelial cells into the interstitial fluid, in a process calleddiapedesis.

A direct inguinal hernia is a form of groin hernia that occurs when abdominal viscera protrude through a weakness in the posterior wall of the inguinal canal, notably through Hesselbach’s triangle, medial to the inferior epigastric veins.

An exudate is an inflammatory fluid that leaks out of the intravascular space due to increased vascular permeability and intravascular pressure. It is mostly caused by local processes and can occur in the following conditions:1) Infection (e.g. pneumonia)2) Malignancy3) Pericarditis4) Collagen vascular diseases, e.g., Rheumatoid ArthritisMyxoedema is a state of severe hypothyroidism in which deposition of mucopolysaccharides occurs in the dermis. This causes a transudative effusion, typically in the pretibial region.

Erythropoietin is a glycoprotein hormone that regulates the formation of red blood cells (red cell production). It is mostly produced by interstitial fibroblasts in the kidney, which are located near the PCT. It is also produced in the liver’s perisinusoidal cells, however this is more common during the foetal and perinatal periods.The kidneys produce and secrete erythropoietin in response to hypoxia. On red blood cells, erythropoietin has two main effects:- It encourages stem cells in the bone marrow to produce more red blood cells.- It protects red blood cell progenitors and precursors from apoptosis by targeting them in the bone marrow.As a result of the increased red cell mass, the oxygen-carrying capacity and oxygen delivery increase.

One of the commonest antispasmodic medications that is used is hyoscine butylbromide. It is an antimuscarinic and typical side effects of this class of drugs include:- dilation of pupils with loss of accommodation (cycloplegia) -photophobia resulting in blurred vision (Blind as a bat) -dry mouth, eyes and skin (Dry as a bone), -elevated temperature (Hot as a hare)-skin flushing (Red as a beet)-confusion or agitation particularly in the elderly (Mad as a hatter)-reduced bronchial secretions-transient bradycardia followed by tachycardia, palpitation and arrhythmias-urinary retention and/or constipation

Calcium that is not protein bound is freely filtered in the glomerulus, and there is reabsorption along the nephron.About 70% is reabsorbed in the proximal tubule.About 20% is reabsorbed in the thick ascending limb of the loop of Henle.This reabsorption is mainly passive and paracellular and driven by sodium reabsorption. Sodium reabsorption causes water reabsorption, which raises tubular calcium concentration, causing calcium to diffuse out of the tubules. The positive  lumen potential also encourages calcium to leave the tubule.About 5 – 10% is reabsorbed in the distal convoluted tubule.Less than 0.5% is reabsorbed in the collecting ducts.Calcium reabsorption in the distal nephron is active and transcellular and is the major target for hormonal control.Calcium homeostasis is primarily controlled by three hormones: parathyroid hormone, activated vitamin D and calcitonin.Parathyroid hormone acts on the kidneys to increase calcium reabsorption in the distal tubule by activating Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane (and to decrease phosphate reabsorption in the proximal tubule).Activated vitamin D acts to increase calcium reabsorption in the distal tubule via activation of a basolateral Ca2+ATPase pump (and to increase phosphate reabsorption).Calcitonin acts to inhibit renal reabsorption of calcium (and phosphate).

Parkinson’s disease (PD) is one of the most common neurologic disorders, affecting approximately 1% of individuals older than 60 years and causing progressive disability that can be slowed but not halted, by treatment. The 2 major neuropathologic findings in Parkinson’s disease are loss of pigmented dopaminergic neurons of the substantia nigra pars compacta and the presence of Lewy bodies and Lewy neurites. See the images below.

In the thick ascending limb is the part of the loop of Henle in which there is active reabsorption of Na+and Cl- ions from the tubular fluid. This occurs via the Na+/K+/2Cl-symporter on the apical membrane. This mechanism is by:1. Na+ions are transported across the basolateral membrane by Na+pumps and the Cl-ions by diffusion. 2. K+leaks back into the tubular fluid via apical ROMK K+channels which creates a positive charge. 3. This positive charge drives the reabsorption of cations (Na+, K+, Ca2+, Mg2+) through paracellular pathways. 4. Due to the thick ascending limb being impermeable to water, the tubular fluid osmolality is reduced by ion reabsorption, the interstitial fluid osmolality is increased, and an osmotic difference is created.

Digoxin is contraindicated in:Supraventricular arrhythmias associated with accessory conduction pathways e.g. Wolff-Parkinson-White syndromeVentricular tachycardia or fibrillationHeart conduction problems e.g. second degree or intermittent complete heart blockHypertrophic cardiomyopathy (unless concomitant atrial fibrillation and heart failure but should be used with caution)

Tetanus is caused by Clostridium tetani, a bacterium. Tetanus can cause mild spasms to severe whole-body contractions, suffocation, and heart attack. Gas gangrene and food poisoning are both caused by Clostridium perfringens. Pseudomembranous colitis is caused by Clostridium difficile. Urinary tract infections, respiratory infections, dermatitis, soft tissue infections, bacteraemia, bone and joint infections, gastrointestinal infections, and a variety of systemic infections are all caused by Pseudomonas aeruginosa. Pharyngitis, skin infections, acute rheumatic fever, scarlet fever, poststreptococcal glomerulonephritis, toxic shock–like syndrome, and necrotizing fasciitis can all be caused by Streptococcus pyogenes infection.

Bupivacaine has a longer duration of action than the other local anaesthetics, up to 8 hours when used for nerve blocks. It has a slow onset, taking up to 30 minutes for full effect. It is often used in lumbar epidural blockade and is particularly suitable for continuous epidural analgesia in labour, or for postoperative pain relief. It is the principal drug used for spinal anaesthesia.

Antacids such as aluminium hydroxide and magnesium carbonate are commonly used. They’re both water-insoluble and can reduce the absorption of drugs taken together. Allow at least 1-2 hours between taking these antacids and any other medications.Because it reduces gastrointestinal phosphate absorption, aluminium hydroxide can also be used to treat hyperphosphatemia in patients with renal failure.Magnesium carbonate has a laxative effect, whereas aluminium hydroxide has a constipating effect.

Hypoperfusion, renal failure, and the oligohydramnios sequence are all linked to ACE inhibitor use in the second and third trimesters. The oligohydramnios sequence refers to a foetus’ or neonate’s atypical physical appearance as a result of oligohydramnios in the uterus. It’s also linked to aortic arch obstructive malformations and patent ductus arteriosus.The inhibitory effects on the renin-angiotensin-aldosterone system appear to be the cause of these defects. To avoid these risks, ACE inhibitors should be stopped before the second trimester.

The hookworm life cycle begins with the passage of eggs from an adult host into the stool. Hookworm eggs hatch in the soil to release larvae that mature into infective larvae. Infection is usually transmitted by larval penetration into human skin (duodenal infection may also be transmitted by the oral route). From the skin, larvae migrate into the blood vessels and are carried to the lungs, where they penetrate the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed.

Although Ca2+entry during the action potential (AP) is essential for contraction, it only accounts for about 25% of the rise in intracellular Ca2+. The rest is released from Ca2+stores in the sarcoplasmic reticulum (SR). APs travel down invaginations of the sarcolemma called T-tubules, which are close to, but do not touch, the terminal cisternae of the SR. During the AP plateau, Ca2+enters the cell and activates Ca2+sensitive Ca2+release channels in the sarcoplasmic reticulum allowing stored Ca2+to flood into the cytosol; this is called Ca2+-induced Ca2+release. The amount of Ca2+released is dependent on how much is stored, and on the size of the initial Ca2+influx during the AP.

The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla.Its origin lies anterior surface of the medial half of the clavicle, the anterior surface of the sternum, the first 7 costal cartilages, the sternal end of the sixth rib, and the aponeurosis of the external oblique of the anterior abdominal wall.The insertion of the pectoralis major is at the lateral lip of the intertubercular sulcus of the humerus. There are 2 heads of the pectoralis major, the clavicular and the sternocostal, which reference their area of origin. The function of the pectoralis major is 3-fold and dependent on which heads of muscles are involved:- Flexion, adduction and medial rotation of the arm at the glenohumeral joint- Clavicular head causes flexion of the extended arm- Sternoclavicular head causes extension of the flexed armArterial supply of the pectoralis major, the pectoral artery, arises from the second branch of the axillary artery, the thoracoacromial trunk.The 2 heads of the pectoralis major have different nervous supplies. The clavicular head derives its nerve supply from the lateral pectoral nerve. The medial pectoral nerve innervates the sternocostal head. The lateral pectoral nerve arises directly from the lateral cord of the brachial plexus, and the medial pectoral nerve arises from the medial cord.

ADH, or antidiuretic hormone, is a hormone that regulates water and electrolyte balance. It is released in response to a variety of events, the most important of which are higher plasma osmolality or lower blood pressure. ADH increases plasma volume and blood pressure via acting on the kidneys and peripheral vasculature.ADH causes extensive vasoconstriction by acting on peripheral V1 Receptors.ADH binds to B2 Receptors in the terminal distal convoluted tubule and collecting duct of the kidney, increasing transcription and aquaporin insertion in the cells that line the lumen. Aquaporins are water channels that allow water to pass through the tubule and into the interstitial fluid via osmosis, lowering urine losses.The permeability of the distal collecting duct (the section within the inner medulla) to urea is likewise increased by ADH. More urea travels out of the tubule and into the peritubular fluid, contributing to the counter current multiplier, which improves the Loop of Henle’s concentrating power.Overall, there is enhanced urea and water reabsorption in the presence of ADH, resulting in modest amounts of concentrated urine. There is minimal urea and water reabsorption in the absence of ADH, resulting in huge amounts of dilute urine.

DKA is characterised by the biochemical triad:1. Hyperglycaemia (> 11 mmol/L)2. Ketonaemia (> 3 mmol/L)3. Acidosis (pH < 7.3 +/- HCO3 < 15 mmol/L)

A single dose of IV benzodiazepine will terminate the seizure in 60 to 80 percent of patients who present with seizures.Because benzodiazepines are lipid-soluble, they cross the blood-brain barrier quickly. This explains their quick onset of action.As a first-line treatment, IV lorazepam should be given. If IV lorazepam is not available, IV diazepam can be used instead, and buccal midazolam can be used if intravenous access cannot be established quickly. Lorazepam can be administered via the rectal route, but it is less reliable and has a lower absorption rate and bioavailability.

Local currents propagate action potentials down the axons of neurons. This local current flow following depolarisation results in the depolarisation of the neighbouring axonal membrane, and when this region approaches the threshold, more action potentials are generated and so forth. Due to the refractory period, portions of the membrane that have recently depolarized will not depolarize again, resulting in the action potential only being able to go in one direction.The square root of axonal diameter determines the velocity of the action potential; the axons with the biggest diameter have the quickest conduction velocities. When a neuron is myelinated, the speed of the action potential rises as well.The myelin sheath is an insulating coating that surrounds certain neural axons. By increasing membrane resistance and decreasing membrane capacitance, the myelin sheath improves conduction. This enables faster electrical signal transmission via a neuron, making them more energy-efficient than non-myelinated neuronal axons.Electrical impulses are quickly transmitted from one node to the next, causing depolarization of the membrane above the threshold and triggering another action potential, which is then transmitted to the next node. An action potential is rapidly conducted down a neuron in this manner. Saltatory conduction is the term for this.Multiple sclerosis is an example of a clinical disorder in which the myelin sheath is affected. It is an immune-mediated disorder in which certain nerve cells in the brain and spinal cord become demyelinated. The ability of some areas of the nervous system to properly transmit action potentials is disrupted by demyelination, resulting in a variety of neurological symptoms and indications.

Heparin works by binding to and activating the enzyme inhibitor antithrombin III. Antithrombin III inactivates thrombin (factor IIa) by forming a 1:1 complex with thrombin. The heparin-antithrombin III complex also inhibits factor Xa and some other proteases involved with clotting. The heparin-ATIII complex can also inactivate IX, XI, XII, and plasmin.Heparin is a polymer of glycosaminoglycan. It occurs naturally and is found in mast cells. Clinically, it is used in two forms:1. Unfractionated: widely varying polymer chain lengths2. Low molecular weight: Smaller polymers only Heparin is not thrombolytic or fibrinolytic. It prevents the progression of existing clots by inhibiting further clotting. The lysis of existing clots relies on endogenous thrombolytics.Heparin is used for:1. Prevention and treatment of venous thromboembolism2. Treatment of disseminated intravascular coagulation3. Treatment of fat embolism4. Priming of haemodialysis and cardiopulmonary bypass machines

Juxtacapillary receptors (J receptors) are sensory cells that are located within the alveolar walls in juxtaposition to the pulmonary capillaries of the lung.The J receptors are innervated by the vagus nerve and are activated by physical engorgement of the pulmonary capillaries or increased pulmonary interstitial volume, for example, in the presence of pulmonary oedema, pulmonary embolus, pneumonia and barotraumas. They may also be stimulated by hyperinflation of the lung.Stimulation of the J receptors causes a reflex increase in breathing rate and is also thought to be involved in the sensation of dyspnoea. The reflex response that is produced is apnoea, followed by rapid breathing, bradycardia, and hypotension.