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Question 1
Incorrect
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A patient presents to ED with heartburn for which they already take regular antacids. Which of the following drugs can be affected if taken with antacids:
Your Answer: Bendroflumethiazine
Correct Answer: Digoxin
Explanation:Antacids should preferably not be taken at the same time as other drugs since they may affect absorption. When antacids are taken with acidic drugs (e.g. digoxin, phenytoin, chlorpromazine, isoniazid) they cause the absorption of the acidic drugs to be decreased, which causes low blood concentrations of the drugs, which ultimately results in reduced effects of the drugs. Antacids taken with drugs such as pseudoephedrine and levodopa increase absorption of the drugs and can cause toxicity/adverse events due to increased blood levels of the drugs. Antacids that contain magnesium trisilicate and magnesium hydroxide when taken with some other medications (such as tetracycline) will bind to the drugs, and reduce their absorption and effects.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 2
Correct
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Regarding chemical control of respiration, which of the following statements is INCORRECT:
Your Answer: The blood-brain barrier is freely permeable to HCO3 - ions.
Explanation:CSF is separated from the blood by the blood-brain barrier. This barrier is impermeable to polar molecules such as H+and HCO3-but CO2can diffuse across it easily. The pH of CSF is therefore determined by the arterial PCO2and the CSF HCO3-and is not affected by blood pH.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 3
Incorrect
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Which of the following cytokines is important for the maintenance of granulomatous inflammation:
Your Answer: IL-4
Correct Answer: TNF-alpha
Explanation:Granulomatous inflammation is a distinctive pattern of chronic inflammation that is encountered in a limited number of infectious and some non-infectious conditions. Briefly, a granuloma is a cellular attempt to contain an offending agent that is difficult to eradicate. In this attempt, there is often strong activation of T lymphocytes leading to macrophage activation, which can cause injury to normal tissues. IL-1 is important in initiating granuloma formation, IL-2 can cause them to enlarge and TNF-α maintains them.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 4
Incorrect
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Which of the following statements is correct regarding gentamicin?
Your Answer: Gentamicin is effective against haemolytic streptococci.
Correct Answer: Gentamicin is ineffective against anaerobic bacteria.
Explanation:Gentamicin is the aminoglycoside of choice in the UK and is a parenterally administered, broad spectrum antibiotic typically used for moderate to severe gram negative infections. However, it is inactive against anaerobes. There is poor activity against haemolytic streptococci and pneumococci. It is usually given in conjunction with a penicillin or metronidazole (or both) when used for the blind treatment of undiagnosed serious infections. Nephrotoxicity and ototoxicity are the main toxic effects due to damage to the vestibulocochlear nerve (CN VIII).It is contraindicated in myasthenia gravis and should be used with great care in renal disease as it may result in accumulation and a higher risk of toxic side effects.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 5
Correct
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Regarding bronchiolitis, which of the following statements is CORRECT:
Your Answer: Chest x-ray may show hyperinflation and increased peribronchial markings.
Explanation:Acute bronchiolitis is caused most commonly by respiratory syncytial virus, occurring mostly in children aged 6 months to 2 years. Children with bronchiolitis are febrile and tachypnoeic with a dry cough and difficulty feeding. Examination may reveal chest hyperinflation, respiratory distress, wheezing and fine end-inspiratory crepitations. Chest x-ray may show hyperinflation and increased peribronchial markings (although CXR should only performed if there is diagnostic uncertainty or an atypical course). Treatment is usually supportive, aerosolized ribavirin is reserved for severely ill or immunocompromised patients.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 6
Incorrect
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Which of the following movements does the iliacus muscle produce?
Your Answer: Medial rotation of the thigh at the hip joint
Correct Answer: Flexion of the thigh at the hip joint
Explanation:The iliacus flexes the thigh at the hip joint when the trunk is stabilised. It flexes the trunk against gravity when the body is supine.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 7
Incorrect
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A 62-year-old woman is brought to the Emergency Department as she is acutely unwell. Her attendants inform you that she was recently started on lithium as a mood stabilizer. You instantly send a blood sample to check for lithium levels. What is the usual therapeutic range for lithium?
Your Answer: 1.0-2.0 mmol/l
Correct Answer: 0.4-0.8 mmol/l
Explanation:Lithium is the drug of choice for recurrent bipolar illness but should be carefully monitored as it has a very low therapeutic index. The normal therapeutic range is 0.4-0.8 mmol/l. The lower end of the range is usually the target for the elderly and as maintenance therapy. Toxicity is usually seen at levels >1.5 mmol/l. Samples should be taken 12 hours after the dose, and levels should be checked one week after starting therapy and one week after every change in dosage.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 8
Incorrect
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A 16-year old boy is brought to the emergency room after suffering a traffic accident. Upon examination, there is noted ipsilateral loss of proprioception and vibration, ipsilateral motor loss, and contralateral loss of pain and temperature sensation. A spinal cord injury is given as a diagnosis.Which of the following is the most probable cause of this manifestation?
Your Answer: Complete thoracic injury
Correct Answer: Brown-Séquard syndrome
Explanation:Brown-Sequard Hemicord Syndrome consists of ipsilateral weakness (corticospinal tract) and loss of joint position and vibratory sense (posterior column), with contralateral loss of pain and temperature sense (spinothalamic tract) one or two levels below the lesion. Segmental signs, such as radicular pain, muscle atrophy, or loss of a deep tendon reflex, are unilateral. Partial forms are more common than the fully developed syndrome.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 9
Incorrect
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An 80-year-old female complains of chest pain characteristic of angina. A dose of glyceryl trinitrate (GTN) is administered that resolves the chest pain rapidly. Which ONE of the following is released on the initial metabolism of GTN?
Your Answer: Cyclic AMP
Correct Answer: Nitrite ions
Explanation:Angina pectoris is the most common symptom of ischemic heart disease and presents with chest pain relieved by rest and nitro-glycerine. Nitrates are the first-line treatment to relieve chest pain caused by angina. The commonly used nitrates are: 1. Glyceryl trinitrate 2. Isosorbide dinitrate The nitrate drugs are metabolized in the following steps: 1. Release Nitrite ions (NO2-), which are then converted to nitric oxide (NO) within cells. 2. NO activates guanylyl cyclase, which causes an increase in the intracellular concentration of cyclic guanosine-monophosphate (cGMP) in vascular smooth muscle cells. 3. Relaxation of vascular smooth muscle.Although nitrates are potent coronary vasodilators, their principal benefit in the management of angina results from a predominant mechanism of venous dilation:- Bigger veins hold more blood- Takes blood away from the left ventricle- Lowers LVEDV (preload), LA pressure- Less pulmonary oedema → improved dyspnoea
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 10
Correct
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Regarding box and whisker plots, which of the following statements is true?
Your Answer: 25% of the values lie below the lower quartile
Explanation:A box and whisker plot is defined as a graphical method of displaying variation in a set of data. In most cases, a histogram analysis provides a sufficient display, but a box and whisker plot can provide additional detail while allowing multiple sets of data to be displayed in the same graph.The procedure to develop a box and whisker plot comes from the five statistics below:(1) Minimum value: The smallest value in the data set(2) Second quartile: The value below which the lower 25% of the data are contained(3) Median value: The middle number in a range of numbers(4) Third quartile: The value above which the upper 25% of the data are contained(5) Maximum value: The largest value in the data set
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This question is part of the following fields:
- Evidence Based Medicine
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Question 11
Incorrect
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A 60-year-old man comes to your department with complaints of epigastric pain. There is a history of rheumatoid arthritis and he has been taking ibuprofen 200 mg TDS for the last 2 weeks.The following scenarios would prompt you to consider the co-prescription of a PPI for gastroprotection with NSAIDs EXCEPT?
Your Answer: Co-prescription of prednisolone
Correct Answer: Long-term use for chronic back pain in a patient aged 30
Explanation:The current recommendations by NICE suggest that gastro-protection should be considered if patients have ≥1 of the following:Aged 65 or older- Using maximum recommended dose of an NSAID- History of peptic ulcer or GI bleeding- Concomitant use of: antidepressants like SSRIs and SNRIs, Corticosteroids, anticoagulants and low dose aspirin- Long-term NSAID usage for: long-term back pain if older than 45 and patients with OA or RA at any ageThe maximum recommended dose of ibuprofen is 2.4 g daily and this patient is on 400 mg of ibuprofen TDS.
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This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 12
Incorrect
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You see a patient in the Emergency Department with features consistent with a diagnosis of type I diabetes mellitus.Which of these is MOST suggestive of type I diabetes mellitus?
Your Answer: Onset under the age of 20
Correct Answer: History of recent weight loss
Explanation:A history of recent weight loss is very suggestive of an absolute deficiency of insulin seen in type I diabetes mellitus.An age of onset of less than 20 years makes a diagnosis of type I diabetes mellitus more likely. However, an increasing number of obese children and young people are being diagnosed with type II diabetes.Microalbuminuria, peripheral neuropathy, and retinopathy all occur in both type I and type II diabetes mellitus. They are not more suggestive of type I DM.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 13
Incorrect
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Where is angiotensin I primarily converted to angiotensin II:
Your Answer: Kidneys
Correct Answer: Lungs
Explanation:Angiotensin I is converted to angiotensin II by the removal of two C-terminal residues by the enzyme angiotensin-converting enzyme (ACE). This primarily occurs in the lungs, although it does also occur to a lesser degree in endothelial cells and renal epithelial cells.The main actions of angiotensin II are:Vasoconstriction of vascular smooth muscle (resulting in increased blood pressure)Vasoconstriction of the efferent arteriole of the glomerulus (resulting in an increased filtration fraction and preserved glomerular filtration rate)Stimulation of aldosterone release from the zona glomerulosa of the adrenal cortexStimulation of anti-diuretic hormone (vasopressin) release from the posterior pituitaryStimulation of thirst via the hypothalamusActs on the Na+/H+ exchanger in the proximal tubule of the kidney to stimulate Na+reabsorption and H+excretion
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This question is part of the following fields:
- Physiology
- Renal
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Question 14
Incorrect
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On which of the following is preload primarily dependent?
Your Answer: Stroke volume
Correct Answer: End-diastolic volume
Explanation:Preload refers to the initial stretching of the cardiac myocytes before contraction. It is therefore related to muscle sarcomere length. The sarcomere length cannot be determined in the intact heart, and so, other indices of preload are used, like ventricular end-diastolic volume or pressure. The end-diastolic pressure and volume of the ventricles increase when venous return to the heart is increased, and this stretches the sarcomeres, which increase their preload.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 15
Correct
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Regarding the hard palate, which of the following statements is CORRECT:
Your Answer: Lymphatic vessels from the palate usually drain into deep cervical lymph nodes.
Explanation:Lymphatic vessels from the pharynx and palate drain into the deep cervical lymph nodes.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 16
Correct
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Which of the following intravenous induction drugs results in the highest drop in blood pressure:
Your Answer: Propofol
Explanation:Propofol’s most frequent side effect is hypotension, which affects 17% of paediatric patients and 26% of adults. This is attributable to systemic vasodilation as well as a decrease in preload and afterload. Propofol has a little negative inotropic impact as well. The drop in blood pressure is dosage-dependent and is more noticeable in the elderly, thus this should be expected.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 17
Incorrect
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Damage to this nerve affects the flexor digitorum longus.
Your Answer: Sciatic nerve
Correct Answer: Tibial nerve
Explanation:Like all muscles in the deep posterior compartment of the leg, flexor digitorum longus muscle is innervated by branches of the tibial nerve (root value L5, S1 and S2) which is a branch of sciatic nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 18
Incorrect
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Which of the following statements concerning hepatitis D is TRUE:
Your Answer: It can only be transmitted with, or to somebody who is infected with, Hepatitis C.
Correct Answer: It can only be transmitted with, or to somebody who is infected with, Hepatitis B.
Explanation:Hepatitis D virus (HDV) is an RNA virus that was discovered in 1977 and is structurally unrelated to the hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV) viruses. HDV causes a unique infection that requires the assistance of HBV viral particles to replicate and infect hepatocytes. Its clinical course is varied and ranges from acute, self-limited infection to acute, fulminant liver failure. Chronic liver infection can lead to end-stage liver disease and associated complications (including accelerated fibrosis, liver decompensation, and hepatocellular carcinoma).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 19
Correct
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A 22 year old student has recently returned from travelling around Kenya and presents to ED with a headache and persistent fever. Malaria is being considered as a potential diagnosis. Which of the following strains of malaria is most likely:
Your Answer: Plasmodium falciparum
Explanation:Malaria is an infectious disease transmitted by female of theAnophelesgenus of mosquito. It is a parasitic infection caused by the genusPlasmodium. Five species are recognized as causing disease in humans;Plasmodium falciparum,Plasmodium ovale,Plasmodium vivax,Plasmodium malariaeandPlasmodium knowlesi.The classic symptom of malaria is the malarial paroxysm, a cyclical occurrence of a cold phase, where the patient experiences intense chills, a hot stage, where the patient feels extremely hot and finally a sweating stage, where the fever declines and the patient sweats profusely. On examination the patient may show signs of anaemia, jaundice and have hepatosplenomegaly without evidence of lymphadenopathy.Plasmodium falciparum is the most serious form and is responsible for most deaths. Severe or complicated malaria is suggested by the presence of impaired consciousness, seizures, hypoglycaemia, anaemia, renal impairment, respiratory distress and spontaneous bleeding.Plasmodium falciparum is the most likely type in this case in view of the presentation.Haemoglobinuria and renal failure following treatment is suggestive of blackwater fever, which is caused byPlasmodium falciparum. An autoimmune reaction between the parasite and quinine causes haemolysis, haemoglobinuria, jaundice and renal failure. This can be fatal.The benign malarias: P.vivax, P. malariae and P.ovale are usually treated with chloroquine. A course of primaquine is also required in P.vivax and P.ovale infection. Artesunate is the drug treatment of choice for Plasmodium falciparum malaria. Quinine can still be used where artesunate is not available. Often combination therapy with drugs such as doxycycline or fansidar is also required.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 20
Incorrect
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Regarding the brachioradialis muscle, which of the following statements is true?
Your Answer: It is innervated by the musculocutaneous nerve
Correct Answer: It assists with supination of the forearm at the radioulnar joints
Explanation:Brachioradialis is a fusiform muscle located in the lateral part of the posterior forearm. Along with extensor carpi radialis brevis and extensor carpi radialis longus, it comprises the radial group of forearm muscles, which belong to the superficial layer of posterior forearm muscles. Although anatomically part of the posterior forearm muscles, which are known to be forearm extensors, brachioradialis’ fibre orientation enables it to rather flex the forearm, and aids in supination of the forearm at the radioulnar joint.The brachioradialis muscle originates from the upper two-thirds of the lateral supracondylar ridge of humerus and the anterior surface of the lateral intermuscular septum of the arm. It slides over the lateral surface of the elbow joint, entering the anterolateral cubital area. The muscle fibres course inferiorly down the radial part of the anterior forearm, forming a thick tendon in approximately the middle of the forearm. This tendon then traverses the remainder of the forearm, inserting near the wrist, just proximal to the styloid process of radius.Brachioradialis is innervated by the radial nerve (from the root values C5-C6) that stems from the posterior cord of the brachial plexus. Blood supply to the brachioradialis muscle comes from branches of the radial artery, radial recurrent artery and the radial collateral branch of the deep brachial artery.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 21
Incorrect
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A 45-year-old African American male presents to your clinic complaining of swelling of his feet for the past six months. On examination, there is periorbital and pedal oedema. A 24-hour urine collection is ordered, which shows 8 g of protein. The serum cholesterol is ten mmol/L. You order a renal biopsy to confirm the diagnosis. Which one of the following findings are you most likely to see in this patient's biopsy?
Your Answer: Mesangiocapillary glomerulonephritis
Correct Answer: Focal segmental glomerulosclerosis
Explanation:This patient has Nephrotic Syndrome confirmed by the presence of 1. Heavy proteinuria (greater than 3-3.5 g/24 hours)2. Hypoalbuminemia (serum albumin < 25 g/L)3. Generalised oedema (often with periorbital involvement)4. Severe hyperlipidaemia (total cholesterol is often > 10 mmol/L). Focal Segmental Glomerulosclerosis will be the most likely answer as it is the most common cause of Nephrotic Syndrome in African American adults. Minimal change disease is the most common cause of nephrotic syndrome in children. Membranous glomerulonephritis is the most common cause of Nephrotic Syndrome in Caucasian adults. In IgA nephropathy, patients will complain of cola-coloured urine. Mesangiocapillary glomerulonephritis presents with features of Nephritic Syndrome.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 22
Correct
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A patient suffers from an injury and as a consequence, the nerve that was damaged innervates the obturator internus muscle.In which of the following nerves is the obturator internus muscle innervated by?
Your Answer: Nerve to obturator internus
Explanation:The obturator internus is innervated by the obturator internus nerve (L5–S2), a branch of sacral plexus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 23
Incorrect
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Regarding cardiac excitation-contraction coupling, which of the following statements is CORRECT:
Your Answer: Ca 2+ is transported out of the cell predominantly by Ca 2+ ATPase.
Correct Answer: The Treppe effect refers to an increase in contractility secondary to an increase in heart rate.
Explanation: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). In relaxation, about 80% of Ca2+is rapidly pumped back into the SR (sequestered) by Ca2+ATPase pumps. The Ca2+that entered the cell during the AP is transported out of the cell primarily by the Na+/Ca2+exchanger in the membrane. When more action potentials occur per unit time, more Ca2+enters the cell during the AP plateau, more Ca2+is stored in the SR, more Ca2+is released from the SR and thus more Ca2+is left inside the cell and greater tension is produced during contraction. Increased heart rate increases the force of contraction in a stepwise fashion as intracellular [Ca2+] increases cumulatively over several beats; this is the Treppe effect. Cardiac glycosides such as digoxin have a positive inotropic effect.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 24
Incorrect
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Antidiuretic hormone (ADH) has which of the following effects:
Your Answer: Increases water retention by increasing sodium reabsorption in the distal convoluted tubule
Correct Answer: Increases urine osmolality
Explanation:ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, raising cAMP levels and causing intracellular vesicles to fuse with the apical membrane. In their membrane these vesicles have water channels called aquaporins, which increase the water permeability allowing greater water reabsorption and concentration of urine. ADH also binds to V1 receptor receptors on vascular smooth muscle, causing vasoconstriction and enhancing the effect of aldosterone on sodium reabsorption in the distal tubule. ADH release is stimulated primarily by raised plasma osmolality detected by osmoreceptors in the anterior hypothalamus. Other factors that increase ADH release include: extracellular fluid volume depletion, angiotensin II, nausea, pain, stress, exercise, emotion, hypoglycaemia. ADH release is inhibited by low plasma osmolality, alcohol, caffeine, glucocorticoids and atrial natriuretic peptide (ANP). ADH deficiency (or an inadequate response to ADH) results in diabetes insipidus. Excess levels of ADH results in syndrome of inappropriate ADH secretion (SIADH).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 25
Correct
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Which of the following diseases is caused by a build-up of lymphoblasts in the bone marrow?
Your Answer: Acute lymphoblastic leukaemia
Explanation:Acute lymphoblastic leukaemia (ALL) is a clonal (malignant) bone marrow disorder in which early lymphoid precursors multiply and replace the marrow’s normal hematopoietic cells. ALL is most common between the ages of 3 and 7, with 75 percent of cases occurring before the age of 6.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 26
Incorrect
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All of the following single clinical risk groups is considered eligible to receive the seasonal influenza vaccination, except:
Your Answer: Patients with diet-controlled diabetes
Correct Answer: Patients with hypertension
Explanation:The following is the list of all the health and age factors that are known to increase a person’s risk of getting serious complications from flu:- Adults 65 years and older- Children younger than 2 years old- Asthma- Neurological and neurodevelopmental conditions- Blood disorders (such as sickle cell disease)- Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)- Endocrine disorders (such as diabetes mellitus)- Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)- Kidney diseases- Liver disorders- Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)- People who are obese with a body mass index [BMI] of 40 or higher- People younger than 19 years old on long-term aspirin- or salicylate-containing medications.- People with a weakened immune system due to disease (such as people with HIV or AIDS, or some cancers such as leukaemia) or medications (such as those receiving chemotherapy or radiation treatment for cancer, or persons with chronic conditions requiring chronic corticosteroids or other drugs that suppress the immune system)- People who have had a stroke- Pregnant people and people up to 2 weeks after the end of pregnancy- People who live in nursing homes and other long-term care facilities
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 27
Correct
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A 40-year-old man complains of pain and redness in his lower thigh due to an insect bite. He was diagnosed with cellulitis. Select the first-line antibiotic for cellulitis.
Your Answer: Flucloxacillin
Explanation:Cellulitis is most commonly caused by bacteria from the group Aß-hemolytic streptococcus. Cellulitis can be caused by animal bites. For uncomplicated cellulitis, flucloxacillin is the first-line antibiotic. Because it is beta-lactamase stable, it is efficient against Staphylococcus aureus.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 28
Incorrect
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An ambulance transports a 72-year-old woman to the Emergency Department. She is confused, has been vomiting and having stomach pains. Digoxin is one of her medications.Which of the following claims about digoxin is correct?
Your Answer: Hyperkalaemia can predispose to digoxin toxicity
Correct Answer: Therapeutic plasma levels are between 1.0-1.5 nmol/l
Explanation:Digoxin is a cardiac glycoside that is used to treat atrial fibrillation and flutter, as well as congestive heart failure. In cardiac myocytes, it works by inhibiting the membrane Na/K ATPase. Through Na/Ca exchange, this raises intracellular sodium concentration and indirectly increases intracellular calcium availability. Increased intracellular calcium levels have both a positive inotropic and negative chronotropic effect.Digoxin therapeutic plasma levels are typically between 1.0 and 1.5 nmol/l, though higher concentrations may be required, and the value varies between laboratories. At concentrations greater than 2 nmol/l, the risk of toxicity increases dramatically.In patients with normal renal function, digoxin has a long plasma half-life of 36 to 48 hours. This can take up to 5 days in patients with impaired renal function.Hypokalaemia, rather than hyperkalaemia, has been shown to increase the risk of digoxin toxicity.In the treatment of persistent and permanent atrial fibrillation, digoxin is no longer widely used. Beta-blockers, also known as rate-limiting calcium channel blockers, are now the first-line treatment for this condition.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 29
Correct
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A 58-year-old man with a long history of depression presents with a deliberate overdose of verapamil tablets, which he is prescribed for a heart condition.What is verapamil's mechanism of action?
Your Answer: L-type calcium channel blockade
Explanation:Overdosing on calcium-channel blockers should always be taken seriously and regarded as potentially fatal. Verapamil and diltiazem are the two most lethal calcium channel blockers in overdose. These work by binding the alpha-1 subunit of L-type calcium channels, preventing calcium from entering the cell. In cardiac myocytes, vascular smooth muscle cells, and islet beta-cells, these channels play an important role.The standard ABC approach should be used to resuscitate all patients as needed. If life-threatening toxicity is expected, intubation and ventilation should be considered early on. If hypotension and shock are developing, early invasive blood pressure monitoring is recommended.The primary goal of specific treatments is to support the cardiovascular system. These are some of them:1. Fluid resuscitation: Give up to 20 mL of crystalloid per kilogramme of body weight.2. Calcium supplementationThis can be a good way to raise blood pressure and heart rate temporarily.via central venous access: 10% calcium gluconate 60 mL IV (0.6-1.0 mL/kg in children) or 10% calcium chloride 20 mL IV (0.2 mL/kg in children)Boluses can be given up to three times in a row.To keep serum calcium >2.0 mEq/L, consider a calcium infusion.3. Atropine: 0.6 mg every 2 minutes up to 1.8 mg is an option, but it is often ineffective.4. HIET (high-dose insulin-euglycemic therapy):The role of HIET in the step-by-step management of cardiovascular toxicity has changed.5. Vasoactive infusions:This was once thought to be a last-ditch measure, but it is now widely recommended that it be used sooner rather than later.Insulin with a short half-life 50 mL of 50 percent glucose IV bolus plus 1 U/kg bolus (unless marked hyperglycaemia present)Short-acting insulin/dextrose infusions should be continued.Glucose should be checked every 20 minutes for the first hour, then hourly after that.Regularly check potassium levels and replace if they fall below 2.5 mmol/L.Titrate catecholamines to effect (inotropy and chronotropy); options include dopamine, adrenaline, and/or noradrenaline infusions.6. Sodium bicarbonate: Use 50-100 mEq sodium bicarbonate (0.5-1.0 mEq/kg in children) in cases where a severe metabolic acidosis develops.7. Cardiac pacing: It can be difficult to achieve electrical capture, and it may not improve overall perfusion.Bypass AV blockade with ventricular pacing, which is usually done at a rate of less than 60 beats per minute.8. Intralipid transportCalcium channel blockers are lipid-soluble agents, so they should be used in refractory cases.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 30
Incorrect
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Regarding airway resistance, which of the following statements is CORRECT:
Your Answer: Parasympathetic stimulation causes bronchodilation.
Correct Answer: Airway resistance is predominantly determined by the radius of the airway as described by Poiseuille's law.
Explanation:Flow through airways is described by Darcy’s law which states that flow is directly proportional to the mouth-alveolar pressure gradient and inversely proportional to airway resistance. Airway resistance is primarily determined by the airway radius according to Poiseuille’s law, and whether the flow is laminar or turbulent. Parasympathetic stimulation causes bronchoconstriction and sympathetic stimulation causes bronchodilation, but mediated by beta2-adrenoceptors. Muscarinic antagonists e.g. ipratropium bromide cause bronchodilation.
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
