Klebsiellais a genus of non-motile,Gram-negative, rod-shaped bacteriawith a prominent polysaccharide-based capsule. They are routinely found in the nose, mouth and gastrointestinal tract as normal flora, however, they can also behave as opportunistic pathogens.Infections with Klebsiella spp. areusually nosocomial. They are an important cause of ventilator-associated pneumonia (VAP), urinary tract infection, wound infection and bacteraemia. Outbreaks of infections with Klebsiellaspp. in high-dependency units have been described and are associated with septicaemia and high mortality rates. Length of hospital stay and performance of invasive procedures are risk factors forKlebsiellainfections.Primary pneumonia withKlebsiella pneumoniaeis a rare,severe, community-acquired infection associated with a poor outcome.Klebsiella rhinoscleromatis causes a progressive granulomatous infection of the nasal passages and surrounding mucous membranes. This infection is mainly seen in the tropics.Klebsiella ozanae is a recognised cause of chronic bronchiectasis.Klebsiella organisms are resistant to multiple antibiotics including penicillins. This is thought to be a plasmid-mediated property. Agents with high intrinsic activity againstKlebsiellapneumoniaeshould be selected for severely ill patients. Examples of such agents include third-generation cephalosporins (e.g cefotaxime), carbapenems (e.g. imipenem), aminoglycosides (e.g. gentamicin), and quinolones (e.g. ciprofloxacin). These agents may be used as monotherapy or combination therapy. Aztreonam may be used in patients who are allergic to beta-lactam antibiotics.Species with ESBLs (Extended spectrum beta-lactamase) are resistant to penicillins and also cephalosporins such as cefotaxime and ceftriaxone.

Monocytes spend only a short time in the marrow and, after circulating for 20-40 hours, leave the blood to enter the tissues where they become macrophages. Macrophages form the reticuloendothelial system in the liver, spleen and lymph nodes. The lifespan of macrophages may be as long as several months or even years. In tissues the macrophages become self-replicating without replenishment from the blood. They assume specific functions in different tissues e.g. dendritic cells which are involved in antigen presentation to T-cells. Macrophages may be activated by cytokines such as IFN-gamma, contact with complement or direct contact with the target cell through leucocyte adhesion molecules.

Loop diuretics have long been the cornerstone of pulmonary oedema treatment, with furosemide being the most commonly used of these drugs. Premedication with drugs that decrease preload (e.g., nitro-glycerine [NTG]) and afterload (e.g., angiotensin-converting enzyme [ACE] inhibitors) before the administration of loop diuretics can prevent adverse hemodynamic changes.

Flumazenil is a benzodiazepine antagonist that can be helpful in some overdose situations. It works quickly (in less than a minute), but the effects are fleeting, lasting less than an hour. The dose is 200 micrograms every 1-2 minutes with a maximum dose of 3 milligrams per hour.Flumazenil should be avoided by patients who are addicted to benzodiazepines or who take tricyclic antidepressants because it can cause withdrawal symptoms. It can cause seizures or cardiac arrest in these situations.

Heroin is injected into the veins and is the most commonly abused drug. Acute intoxication with opioid overuse is the most common cause of death by drug overdose. The clinical features of opioid overdose are:1. Decreased respiratory rate2. Reduced conscious level or coma3. Decreased bowel sounds4. Miotic (constricted) pupils5. Cyanosis6. Hypotension7. Seizures8. Non-cardiogenic pulmonary oedema (with IV heroin usage)The main cause of death secondary to opioid overdose is respiratory depression, which usually occurs within 1 hour of the overdose. Vomiting is also common, and aspiration can occur.Naloxone is a short-acting, specific antagonist of mu(μ)-opioid receptors. It is used to reverse the effects of opioid toxicity. It can be given by a continuous infusion if repeated doses are required and the infusion rate is adjusted according to the vital signs. Initially, the infusion rate can be set at 60% of the initial resuscitative IV dose per hour.Naloxone has a shorter duration of action (6-24 hours) than most opioids, and so close monitoring according to the respiratory rate and depth of coma with repeated injections is necessary. When repeated doses are needed in opioid addicts, naloxone administration may precipitate a withdrawal syndrome with abdominal cramps, nausea and diarrhoea, but these usually settle within 2 hours.An initial dose of 0.4 to 2 mg can be given intravenously and can be repeated at 2 to 3-minute intervals to a maximum of 10mg. If the intravenous route is inaccessible, naloxone can be administered via an IO line, subcutaneously (SQ), IM, or via the intranasal (IN) route.

Hyoscine butylbromide is an antispasmodic drug that blocks muscarinic receptors and reduces intestinal motility. It is used for gastrointestinal and genitourinary smooth muscle spasms and symptomatic relief of IBS.It has the following contraindications: 1. Closed-angle glaucoma2. Gastrointestinal obstruction3. Intestinal atony4. Paralytic ileus5. Toxic megacolon6. Severe ulcerative colitis7. Significant bladder outflow obstruction8. Urinary retention9. Myasthenia gravisUse cautiously in the following conditions: 1. Acute myocardial infarction (in adults)2. Arrhythmias (may be worsened)3. Autonomic neuropathy4. Hypertension5. Cardiac insufficiency (due to association with tachycardia)6. Congestive cardiac failure (maybe worsened)7. Cardiac surgery (due to association with tachycardia)8. Gastro-oesophageal reflux disease9. Ulcerative colitis10. Prostatic hyperplasia11. Use in children (increased risk of side effects)

Neisseria gonorrhoeae is a Gram-negative diplococcus that causes gonorrhoea. Gonorrhoea is an acute pyogenic infection of nonciliated columnar and transitional epithelium; infection can be established at any site where these cells are found. Gonococcal infections are primarily acquired by sexual contact and occur primarily in the urethra, endocervix, anal canal, pharynx, and conjunctiva.In men, acute urethritis, usually resulting in purulent discharge and dysuria (painful urination), is the most common manifestation. The endocervix is the most common site of infection in women. Symptoms of infection, when present, include dysuria, cervical discharge, and lower abdominal pain. Some cases in women may be asymptomatic leading to complications such as pelvic inflammatory disease. Blood-borne dissemination occurs in less than 1% of all infections, resulting in purulent arthritis and rarely septicaemia. Fever and a rash on the extremities can also be present. Other conditions associated with N. gonorrhoeae include anorectal and oropharyngeal infections. Infections in these sites are more common in men who have sex with men but can also occur in women. Pharyngitis is the chief complaint in symptomatic oropharyngeal infections, whereas discharge, rectal pain, or bloody stools may be seen in rectal gonorrhoea. Approximately 30% to 60% of women with genital gonorrhoea have concurrent rectal infection. Newborns can acquire ophthalmia neonatorum, a gonococcal eye infection, during vaginal delivery through an infected birth canal. Specimens collected for the recovery of N. gonorrhoeae may come from genital sources or from other sites, such as the rectum, pharynx, and jointfluid. According to the 2010 STD Treatment guidelines, cephalosporins (e.g., ceftriaxone, cefixime) are currently recommended treatments.

The fifth cervical nerve passes between the fourth and fifth cervical vertebrae, and the fourth thoracic nerve passes between the fourth and fifth thoracic vertebrae. Therefore, when the cancer metastasizes in this area, they are most likely affected.

Flexor pollicis longus receives nervous supply from the anterior interosseous branch of median nerve, derived from spinal roots C7 and C8.

Bicarbonate is freely filtered at the glomerulus. Less than 0.1% of filtered bicarbonate is normally excreted in the urine (if plasma [HCO3-] increases, maximum tubular transport is exceeded and some HCO3-is excreted in urine). About 80% of bicarbonate is reabsorbed in the proximal tubule. For each H+secreted into the lumen, one Na+and one HCO3-are reabsorbed into the plasma. H+is recycled so there is little net secretion of H+at this stage. A further 10 – 15% of HCO3-is similarly reabsorbed in the thick ascending limb of the loop of Henle. In the early distal tubule, H+secretion is predominantly by Na+/H+exchange but more distally, the Na+gradient is insufficient so secretion is via H+ATPase and H+/K+ATPase in intercalated cells, which contain plentiful carbonic acid. As secreted H+is derived from CO2, new HCO3-is formed and returns to the blood.H+secretion is proportional to intracellular [H+] which itself is related to extracellular pH. A fall in blood pH will therefore stimulate renal H+secretion. In the proximal tubule secretion of H+serves to reclaim bicarbonate from glomerular filtrate so it is not lost, but in the distal nephron, secretion leads to net acid excretion and generation of new bicarbonate.

Fluid filtration out of the capillaries is usually slightly greater than fluid absorption into the capillaries. About 8 L of fluid per day is filtered by the microcirculation and returns to the circulation by the lymphatic system. Lymphatic capillaries drain into collecting lymphatics, then into larger lymphatic vessels. Both of these containing smooth muscle and unidirectional valves. From this point, lymph is propelled by smooth muscle constriction and vessel compression by body movements into afferent lymphatics. It then goes to the lymph nodes where phagocytes remove bacteria and foreign materials. It is here that most fluid is reabsorbed by capillaries, and the remainder returns to the subclavian veins via efferent lymphatics and the thoracic duct. The lymphatic system has a major role to play in the body’s immune defence and also has a very important role in the absorption and transportation of fats.

Infectious mononucleosis can be diagnosed using specific EBV antibodies and a variety of unrelated non-EBV heterophile antibodies.Heterophile antibodies:About 70-90% of patients with EBV infectious mononucleosis produce antibodies against an antigen produced in one species that react against antigens from other species called heterophile antibodies. False positives can be seen with rubella, hepatitis, SLE, malaria, toxoplasmosis, lymphoma and leukaemia. These antibodies can be detected by two main screening tests:The monospot test uses horse red blood cells. It agglutinates in the presence of heterophile antibodies.Paul-Bunnell test uses sheep red blood cells. The blood agglutinates in the presence of heterophile antibodies.EBV-specific antibodies:Patients can remain heterophile-negative after six weeks and are then considered to be heterophile-negative and should be tested for EBV-specific antibodies. EBV-specific antibodies test are helpful if a false positive heterophile antibody test is suspected.The indirect Coombs test is used to detect in-vitro antibody-antigen reactions. It is typically used in antenatal antibody screening and in preparation for blood transfusion.Heterophile antibody tests are generally not positive in the incubation period of infectious mononucleosis (4-6 weeks) before the onset of symptoms.

Elevation of the eyeball is produced by the superior rectus and the inferior oblique muscles.

Iliacus is innervated by the femoral nerve.

Gastrin is a peptide hormone that aids in gastric motility by stimulating the generation of gastric acid by the parietal cells of the stomach. G-cells in the stomach’s pyloric antrum, the duodenum, and the pancreas release it.The following stimuli cause the release of gastrin:Stimulation of the vagus nerveHypercalcaemiastomach bloatingProteins that have been partially digested, particularly amino acids.The presence of acid and somatostatin inhibits the release of gastrin.Gastrin’s main actions are as follows:Gastric parietal cells are stimulated to release hydrochloric acid.ECL cells are stimulated to produce histamine.Gastric parietal cell maturation and fundal growth stimulationCauses the secretion of pepsinogen by the gastric chief cells.Improves antral muscle mobility stimulates gastric contractionsIncreases gastric emptying rate and stimulates pancreatic secretionGallbladder emptying is induced.

Apoptosis is a controlled form of cell death in which no cellular contents are released from the dying cell, and thus no inflammatory reaction is seen. Apoptosis may occur physiologically or pathologically. Apoptosis may be induced in two main ways: by the engagement of surface death receptors e.g. TNF-alpha (extrinsic pathway) or through cellular injury (intrinsic pathway). The end result is the activation of proteases enzymes called caspases which dismantle the cell cytoplasm and nucleus. Apoptotic cells shrink down and fragment into apoptotic bodies, each of which retains an intact cell membrane; apoptotic bodies are then targeted or rapid removal by adjacent cells. Disordered apoptosis is thought to be central to a number of important disease processes, particularly carcinogenesis.

Colchicine is used to prevent or treat gout attacks (flares). It works by reducing swelling and the development of uric acid crystals, which cause pain in the affected joint(s). Colchicine should be avoided by patients who have blood dyscrasias or bone marrow disorders.

Examples of type IV reactions includes:Contact dermatitisHashimoto’s thyroiditisPrimary biliary cholangitisTuberculin skin test (Mantoux test)Chronic transplant rejectionGranulomatous inflammation (e.g. sarcoidosis, Crohn’s disease)

The following nerves provide cutaneous innervation to the scrotum, and other anatomic structures:The perineal nerve supplies the muscles in the urogenital triangle, and the skin on the posterior surface of the scrotum (or labia majora).The genital branch of the genitofemoral nerve supplies the cremaster muscle, the skin over the anterior surface of the thigh, and the anterolateral surface of the scrotum.The ilioinguinal nerve supplies the external oblique, internal oblique, transversus abdominis, skin of the upper medial aspect of thigh, the root of the penis and the anterior surface of the scrotum in the male, and the mons pubis and labia majora in the female.The posterior cutaneous nerve of the thigh, or posterior femoral cutaneous nerve, supplies the skin over the lower medial quadrant of the buttock, the inferior skin of the scrotum or labium majus, and the back of the thigh and the upper part of the leg.

Pectoralis major is a thick, fan-shaped muscle situated in the chest. It makes up the bulk of the chest musculature in the male and lies underneath the breast in the female. It overlies the thinner pectoralis minor muscle.Superficial muscles of the chest and arm showing pectoralis major (from Gray’s Anatomy)Pectoralis major has two heads; the clavicular head and the sternocostal head. The clavicular head originates from the anterior border and medial half of the clavicle. The sternocostal head originates from the anterior surface of the sternum, the superior six costal cartilages and the aponeurosis of the external oblique muscle. It inserts into the lateral lip of the bicipital groove of the humerus.Pectoralis major receives dual innervation from the medial pectoral nerve and the lateral pectoral nerve.Its main actions are as follows:Flexes humerus (clavicular head)Extends humerus (sternocostal head)Adducts and medially rotates the humerusDraws scapula anteriorly and inferiorly

Flucloxacillin is unique in that it is beta-lactamase stable and it can be used in infections caused by beta-lactamase producing staphylococci e.g. S. aureus. It is acid-stable and can therefore be given by mouth as well as by injection. It is used first line for treatment of widespread impetigo infection, cellulitis, mastitis, osteomyelitis, septic arthritis, severe erysipelas, severe/spreading otitis externa and infective endocarditis caused by staphylococci. The most common adverse effects of flucloxacillin include nausea, vomiting, skin rash, and diarrhoea. Cholestatic jaundice and hepatitis may occur very rarely, up to two months after treatment with flucloxacillin has been stopped. Administration for more than 2 weeks and increasing age are risk factors. First line treatment of animal and human bites is co-amoxiclav.

Liquefactive necrosis results in the loss of all cellular structure and the formation of a soft, semi-solid mass. This is commonly seen in the brain after a cerebral infarction.

Malaria results from infection with single-celled parasites belonging to the Plasmodium genus. Five species of Plasmodium are known to cause disease in humans: P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi. Chloroquine remains the mainstay of treatment for uncomplicated vivax malaria.The female Anopheles mosquito serves as the biologic vector and definitive host. A complication of infection with P. falciparum is blackwater fever, a condition characterized by haemoglobinuria. Plasmodium ovale has the longest incubation period, which can be up to 40 days. Plasmodium falciparum has a shorter incubation period of 7-14 days.

Ciprofloxacin increases plasma concentrations of theophylline. There is an increased risk of convulsions when quinolones are given with NSAIDs or theophylline. There is an increased risk of tendon damage when quinolones are given with corticosteroids. Quinolones are known to increase the QT-interval and should not be taken with concomitantly with other drugs that are known to cause QT-interval prolongation. There is an increased risk of myopathy when erythromycin or clarithromycin are taken with simvastatin or atorvastatin.

The obturator externus is innervated by the posterior branch of the obturator nerve, L2-L4.

Blood group AB has both A and B antigens but no antibodies and thus is the universal recipient.

Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that is used short-term (7 days or less) to treat mild to moderate pain in adults and children who are at least 14 years old. Mefenamic acid is also used to treat menstrual pain. It has only minor anti-inflammatory properties and has occasionally been associated with diarrhoea and haemolytic anaemia. If these occur, treatment should be discontinued.

The anterior triangle is the triangular area of the neck found anteriorly to the sternocleidomastoid muscle. It is formed by the anterior border of sternocleidomastoid laterally, the median line of the neck medially and by the inferior border of the mandible superiorly. The apex of the anterior triangle extends towards the manubrium sterni. The anterior triangle contains:Muscles: thyrohyoid, sternothyroid, sternohyoid musclesOrgans: thyroid gland, parathyroid glands, larynx, trachea, esophagus, submandibular gland, caudal part of the parotid glandArteries: superior and inferior thyroid, common carotid, external carotid, internal carotid artery (and sinus), facial, submental, lingual arteriesVeins: anterior jugular veins, internal jugular, common facial, lingual, superior thyroid, middle thyroid veins, facial vein, submental vein, lingual veinsNerves: vagus nerve (CN X), hypoglossal nerve (CN XII), part of sympathetic trunk, mylohyoid nerveThe posterior triangle is a triangular area found posteriorly to the sternocleidomastoid muscle. It has three borders; anterior, posterior and inferior borders. The anterior border is the posterior margin of the sternocleidomastoid muscle. The posterior border is the anterior margin of the trapezius muscle, while the inferior border is the middle one-third of the clavicle. The investing layer of deep cervical fascia and integument forms the roof of the space, while the floor is covered with the prevertebral fascia along with levator scapulae, splenius capitis and the scalene muscles. The inferior belly of omohyoid subdivides the posterior triangle into a small supraclavicular, and a large occipital, triangle.Contents:Vessels: the third part of the subclavian artery, suprascapular and transverse cervical branches of the thyrocervical trunk, external jugular vein, lymph nodesNerves: accessory nerve (CN XI), the trunks of the brachial plexus, fibers of the cervical plexusOf the muscles listed in the options, only the anterior scalene is situated within the posterior triangle of the neck.

Dobutamine is a synthetic isoprenaline derivative that is used to provide inotropic support to patients with low cardiac output caused by septic shock, myocardial infarction, or other cardiac conditions.Dobutamine is a sympathomimetic drug that stimulates beta-1 adrenergic receptors in the heart to produce its primary effect. As a result, it has inotropic properties that increase cardiac contractility and output. It also has a small amount of alpha1- and beta-2-adrenergic activity.A summary of the mechanism and effects of different inotropic agents is shown below:InotropeMechanismEffectsAdrenaline (epinephrine)Beta-1 and -2 agonist at increasing doses;Alpha-agonist at high dosesIncreased cardiac output;Vasoconstriction at higher dosesNoradrenaline (norepinephrine)Mainly alpha-agonist;Beta-1 and -2 agonist at increasing dosesVasoconstriction;Some increased cardiac outputDopamineDopamine agonist at low doses;Beta-1 and -2 agonist at increasing doses;Alpha-agonist at high dosesIncreased cardiac output;Vasoconstriction at higher dosesDobutamineMainly beta-1 agonistIncreased cardiac output

Epstein-Barr virus causes infectious mononucleosis which is a clinical entity characterized by sore throat, cervical lymph node enlargement, fatigue and fever. It is accompanied by atypical large peripheral blood lymphocytes. These atypical lymphocytes, also known as Downey cells, are actually activated CD8 T lymphocytes, most of which are responding to EBV-infected cells.