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Question 1
Incorrect
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A 23 year old student presents to ED with a widespread maculopapular rash. She recently had a sore throat and was started on a course of antibiotics. The most likely antibiotic that she was prescribed is:
Your Answer: Phenoxymethylpenicillin
Correct Answer: Amoxicillin
Explanation:Maculopapular rashes are commonly seen with ampicillin and amoxicillin. However they are not usually related to true penicillin allergy. Very often, they occur in patients with glandular fever and so, broad-spectrum penicillins should not be used blindly, for management and treatment of a sore throat. There is also an increased risk of rash in patients with acute or chronic lymphocytic leukaemia or in cytomegalovirus infection.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 2
Incorrect
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Which of the following is typically used in diabetes mellitus as the cut-off to define hypoglycaemia?
Your Answer: < 7.0 mmol/L
Correct Answer: < 4.0 mmol/L
Explanation:Hypoglycaemia is defined as plasma glucose of less than 4 mmol/L.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 3
Incorrect
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Epigastric pain and haematemesis present in a 67-year-old man. In the emergency room, he is stabilised and referred to the on-call medical team. He has been scheduled for an endoscopy in the morning due to a suspected peptic ulcer. Before transferring him to the ward, you consider giving him a proton pump inhibitor (PPI).Which of the following doses and routes are the best?
Your Answer: Omeprazole 40 mg intravenously
Correct Answer: A PPI should not be prescribed
Explanation:PPIs should not be used prior to endoscopic therapy when an early endoscopic examination is performed within 24 hours of admission, according to current recommendations.High-dose PPI therapy reduces the risk of rebleeding and surgery after endoscopic treatment of severe peptic ulcer bleeding. Both oral and intravenous PPIs produce similar results, and there is no discernible benefit to using the intravenous formulation in patients who can tolerate oral medication.
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This question is part of the following fields:
- Gastrointestinal Pharmacology
- Pharmacology
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Question 4
Correct
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A 70-year-old patient develops bacteraemia following peripheral cannulation.Which of these bacteria is the most likely cause of the infection?
Your Answer: Staphylococcus epidermidis
Explanation:The commonest implicated organisms in hospital-acquired bacteraemia following cannulation are Staphylococcus aureus and Staphylococcus epidermidis. The risk is directly proportional to the length of time in-situ. Peripheral cannula should be replaced after 48 hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 5
Incorrect
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A 40-year-old female presents to the orthopaedic clinic complaining of pain and limited range of motion in the right elbow for the past two days. On examination, the right elbow is extremely tender with erythema and warmth of the overlying skin due to acute inflammation. Which ONE of the following statements is true with regards to acute inflammation?
Your Answer: Increased intravascular osmotic pressure leads to oedema
Correct Answer: Neutrophils are activated and adhere to the endothelium as a result of interaction with endothelial cell adhesion molecules
Explanation:Acute inflammation is defined as inflammation occurring within minutes to hours in response to an injury lasting for less than two weeks. Acute inflammation Rapid onset (minutes to hours)Quick resolution (usually days)Chronic inflammationMay last weeks, months, or yearsThere are five cardinal signs of inflammation:1) Pain2) Redness3) Warmth4) Oedema5) Loss of functionDuring acute inflammation, neutrophils are activated and attracted to the site of inflammation in response to various interleukins and cytokines. This process takes place via the following mechanism:1) MarginationNeutrophils flow nearer the vessel wall rather than in the axial stream, which is referred to as margination2) Rolling along the surface of vascular endothelium3) Adhesion to the endothelium by interaction with adhesion molecules (ICAMS and VCAMS)4) Diapedesis is the movement of neutrophils from the endothelial cells into the interstitial space by squeezing through the gaps between adjacent endothelial cellsBradykinin and histamine are both responsible for vasodilation which causes oedema and decreases intravascular osmotic pressure.Neutrophils dominate early (2 days)- Live longer- Replicate in tissues
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 6
Correct
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Question 7
Incorrect
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A 55-year-old female is urgently rushed into the Emergency Department as she complains of chest pain that is worse on breathing, shortness of breath, palpitations, and haemoptysis. She undergoes a CT pulmonary angiogram, which reveals a large pulmonary embolus. She is immediately started on heparin and shifted to the acute medical ward.Which of the following statements is true regarding heparin?
Your Answer: It is more effective than its low-molecular-weight derivates in preventing mortality from thrombosis
Correct Answer: It activates antithrombin III
Explanation: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 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 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 machinesThere is no evidence that heparin is superior to low-molecular-weight heparins in preventing mortality from thrombosis.Vitamin K is used to reverse the effects of warfarin but not heparin. For heparin, protamine sulphate is used to counteract its effects.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 8
Incorrect
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Which of the following describes the pulse pressure:
Your Answer: Diastolic + systolic pressure/2
Correct Answer: Systolic - diastolic pressure
Explanation:During systole, the pressure in the left ventricle increases and blood is ejected into the aorta. The rise in pressure stretches the elastic walls of the aorta and large arteries and drives blood flow. Systolic pressure is the maximum arterial pressure during systole. During diastole, arterial blood flow is partly maintained by elastic recoil of the walls of large arteries. The minimum pressure reached before the next systole is the diastolic pressure. The difference between the systolic and diastolic pressure is the pulse pressure.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 9
Correct
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An elderly man with chronic heart and lung disease develops Legionnaires' disease. Which of the following clinical features is NOT typical of Legionnaires' disease:
Your Answer: Haemoptysis
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 10
Incorrect
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An 85-year-old woman is brought in from her nursing home. She arrives in the Emergency Department and appears confused. The staff member from the nursing home accompanying her informs you that she takes a water tablet.From her past medical history and records, you deduce that the water tablet is a loop diuretic. Which of the following parts of a nephron does a loop diuretic act on?
Your Answer: Proximal convoluted tubule
Correct Answer: Ascending loop of Henlé
Explanation:Loop diuretics are drugs used to manage and treat fluid overload associated with CHF, liver cirrhosis, and renal disease. The drugs commonly used are:FurosemideBumetanideTorsemideEthacrynic AcidLoop diuretics act on the apical membrane of the thick ascending loop of Henle and inhibit the Na-K-Cl cotransporter. This blocks the reabsorption of sodium and chloride and results in salt-water excretion. This relieves congestion and reduces oedema. Other diuretics act on the following part of the nephron:1. Thiazide diuretics – Na/Cl co-transporter in the distal convoluted tubule2. Osmotic diuretics – PCT and the loop of Henle3. Aldosterone antagonists – distal convoluted tubule 4. Carbonic anhydrase inhibitors – inhibit the carbonic anhydrase and act on proximal tubular cells
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 11
Incorrect
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A 23 year old woman has noticed her skin seems to have a yellow tinge and presents to the emergency room. On examination she is found to have jaundice and mild splenomegaly, and blood tests show that her Hb is 79 g/L. She only takes one regular medication. The medication that is most likely to cause haemolytic anaemia is:
Your Answer: Lithium
Correct Answer: Mefenamic acid
Explanation: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.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 12
Correct
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A patient presents with pain in the wrist and a tingling in the hand. On examination Tinel's test is positive and you diagnose carpal tunnel syndrome. Regarding the carpal tunnel, which of the following statements is INCORRECT:
Your Answer: The tendons of the flexor digitorum profundus, flexor digitorum superficialis and flexor pollicis longus lie within a single synovial sheath.
Explanation:Free movement of the tendons in the carpal tunnel is facilitated by synovial sheaths, which surround the tendons. All of the tendons of the FDP and FDS are contained within a single synovial sheath with a separate sheath enclosing the tendon of the FPL.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 13
Correct
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Which of the following is required for vitamin B12 absorption:
Your Answer: Intrinsic factor
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 14
Incorrect
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Which of the following data types does a pain-scoring system represent?
Your Answer: Quantitative
Correct Answer: Ordinal
Explanation:Pain scoring systems are processes for assessing pain and the severity of illnesses that have been scientifically designed and tested. An example of ordinal categorical data is a pain scoring system.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 15
Incorrect
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An ambulance transports a 37-year-old woman who is having a seizure. She is moved to resuscitation and given a benzodiazepine dose, which quickly ends the seizure. You later learn that she has epilepsy and is usually treated with carbamazepine to control her seizures.What is carbamazepine's main mechanism of action?
Your Answer: GABA reuptake inhibitor
Correct Answer: Sodium channel blocker
Explanation:Carbamazepine is primarily used to treat epilepsy, and it is effective for both focal and generalised seizures. It is not, however, effective in the treatment of absence or myoclonic seizures. It’s also commonly used to treat neuropathic pain, as well as a second-line treatment for bipolar disorder and as a supplement for acute alcohol withdrawal.Carbamazepine works as a sodium channel blocker that preferentially binds to voltage-gated sodium channels in their inactive state. This prevents an action potential from firing repeatedly and continuously.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 16
Correct
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All of the muscles of the tongue (other than the palatoglossus) are innervated by which of the following nerves:
Your Answer: Hypoglossal nerve
Explanation:All of the muscles of the tongue are innervated by the hypoglossal nerve, except for the palatoglossus, which is innervated by the vagus nerve.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 17
Incorrect
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A diagnosis of acute osteomyelitis was made on a patient with a known history of sickle cell disease. He has no joint prosthesis on in-dwelling metal work and no known drug allergies.Which of the following is most likely the causative agent of the case presented above?
Your Answer: Staphylococcus aureus
Correct Answer: Salmonella spp .
Explanation:Patients with sickle cell disease are prone to infection of the bone and bone marrow in areas of infarction and necrosis. Although Staphylococcus aureus is the most common cause of osteomyelitis in the general population, studies have shown that in patients with sickle cell disease, the relative incidence of Salmonella osteomyelitis is twice that of staphylococcal infection.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 18
Incorrect
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A 40-year-old male presents to your clinic complaining of a cough with bloody sputum for the past three months. He has also had fever, night sweats, and has noticed some weight loss over the past three months.Which ONE of the following statements regarding this disease is correct?
Your Answer:
Correct Answer: It can be diagnosed using the Ziehl-Neelson stain
Explanation:Tuberculosis is an infection caused by the microorganism Mycobacterium tuberculosis. TB can affect any organ system in the body, but it most commonly affects the lungs, followed by the lymph nodes. Option Tuberculosis is spread by the faecal-oral route: It is spread by inhalation of droplet nuclei. There are different methods to diagnose a tuberculosis infection. 1) Direct Microscopy: The organisms are visualised using Ziehl-Neelsen or Auramine staining. This is the quickest method to establish a diagnosis and start treatment.2) Culture: M. tuberculosis can be grown on Lowenstein-Jensen or Ogawa mediums, but it can take up to 8 weeks; therefore, ZN staining is also performed to start treatment immediately. Option There are several types of vaccine currently available: The BCG vaccine is the only vaccine approved to prevent TB and is administered at birth. Option Miliary tuberculosis refers to tuberculosis that affects the spine: Miliary tuberculosis refers to a tuberculosis infection disseminated throughout the body’s organ systems via the blood or lymphatics. Pott’s disease is extrapulmonary TB that affects the spine. It usually affects the lower thoracic and upper lumbar regions.Option A Ghon focus typically appears at the apex of a lung: The Ghon focus is a primary sign of TB that forms in the lung of previously unaffected patients. It typically occurs in the mid or lower zones of the lung.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 19
Incorrect
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A clinical audit cycle comprises of 5 steps. Each of these processes are listed below:Which is the correct order that these should occur?1. Observation of practice and collection of data2. Identification of the problem3. Implementation of change4. Definition of criteria and setting of standards5. Analysis of data and comparison of performance with the criteria and standards
Your Answer:
Correct Answer: 2,4,1,5,3
Explanation:An audit assesses if a certain aspect of health care is attaining a recognized standard. This lets care providers and patients know where their service is doing well, and where there could be improvements. The aim is to achieve quality improvement and improve outcomes for patients.Audits are a quality improvement measure and one of the 7 pillars of clinical governance. It allows organizations to continually work toward improving quality of care by showing them where they are falling short, allows them to implement improvements, and reaudit or close the audit cycle to see if beneficial change has taken place.Clinical audits are a cycle with several steps:1. Identification of the problem2. Definition of criteria and setting of standards3. Observation of practice and collection of data4. Analysis of data and comparison of performance with the criteria and standards5. Implementation of change
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This question is part of the following fields:
- Evidence Based Medicine
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Question 20
Incorrect
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A patient presents to your Emergency Department with a laceration on their buttocks requiring closure with sutures.What stage of wound healing is the first to reach completion?
Your Answer:
Correct Answer: Haemostasis
Explanation:The stages of wound healing are: haemostasis, inflammatory, proliferative and remodelling (maturation) phases in that order. The first stage in the healing process of a laceration is haemostasis. Haemostasis is the process of the wound being closed by clotting. The inflammatory phase occurs just after and up to 48 hours after injury– Blood vessels dilate to allow white blood cells, antibodies, growth factors, enzymes and nutrients to reach the wounded area leading to the characteristic signs of inflammation seen. Epithelialisation and angiogenesis are not phases of wound healing but occur during the proliferative phase. This ia after haemolysis and inflammation phases have occurred.The maturation phase is the final phase and occurs when the wound has closed. It involves remodelling of collagen from type III to type I. Apoptosis remove unwanted cells, cellular activity reduces and the number of blood vessels in the wounded area regresses and decreases. This can continues for up to 1 year after injury.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 21
Incorrect
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What is the primary function of collagen in wound healing?
Your Answer:
Correct Answer: Strength and support
Explanation:Key elements of the maturation stage include collagen cross-linking, collagen remodelling, wound contraction, and repigmentation. The tensile strength of the wound is directly proportional to the amount of collagen present. Numerous types of collagen have been identified; types I and III predominate in the skin and aponeurotic layers. Initially, a triple helix (tropocollagen) is formed by three protein chains; two are identical alpha-1 protein chains, and the third is an alpha-2 protein.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 22
Incorrect
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You examine an elderly man who is experiencing chest pain. He doesn't recall all of his medications, but he does know that he takes a diuretic.The enzyme carbonic anhydrase is inhibited by which of the following diuretics?
Your Answer:
Correct Answer: Acetazolamide
Explanation:Acetazolamide is a non-competitive, reversible inhibitor of carbonic anhydrase found in the cytosol of cells and on the brush border of the proximal convoluted tubule. Bicarbonate and hydrogen ions are converted to carbonic acid by carbonic anhydrase, which then converts carbonic acid to carbon dioxide and water. As a result, acetazolamide reduces the availability of hydrogen ions, causing sodium and bicarbonate ions to accumulate in the renal tubule, resulting in diuresis.The mechanism of action of the various types of diuretics is summarised below:1) Loop diuretics, e.g. furosemide, bumetanideAct on the Na.K.2Cl co-transporters in the ascending loop of Henlé to inhibit sodium, chloride and potassium reabsorption.2) Thiazide diuretics, e.g. Bendroflumethiazide, hydrochlorothiazideAct on the Na.Cl co-transporter in the distal convoluted tubule to inhibit sodium and chloride reabsorption.3) Osmotic diuretics, e.g. mannitolIncreases the osmolality of the glomerular filtrate and tubular fluid, increasing urinary volume by an osmotic effect.4) Aldosterone antagonists, e.g. spironolactoneActs in the distal convoluted tubule as a competitive aldosterone antagonist resulting in inhibition of sodium reabsorption and increasing potassium reabsorption.5) Carbonic anhydrase inhibitors, e.g. acetazolamideInhibit the enzyme carbonic anhydrase preventing the conversion of bicarbonate and hydrogen ions into carbonic acid.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 23
Incorrect
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A new blood test is being developed to diagnose DVT. 1000 people presenting to ED with suspected DVT undergo the new blood test and the gold standard doppler ultrasound to confirm the diagnosis. Of the 1000 people, 77 are confirmed to have a DVT. Of the patients diagnosed with DVT, 75 test positive with the new diagnostic test and of the patients not diagnosed with DVT, 125 test positive with the new diagnostic test. What is the negative predictive value of this test:DVT YesDVT NoTotalPositive testa= 75b = 125200Negative testc = 2d = 798800Total779231000
Your Answer:
Correct Answer: 0.99
Explanation:Negative predictive value (NPV) is the proportion of individuals with a negative test result who do not have the disease.Negative predictive value (NPV) = d/(c+d) = 798/800 = 0.99 = 99%This means there is a 99% chance, if the test is negative, that the patient does not have a DVT.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 24
Incorrect
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Which of the following laboratory findings is NOT typical of von Willebrand disease (VWD):
Your Answer:
Correct Answer: Thrombocytopaenia
Explanation:Laboratory findings typically show (although this varies depending on VWD type):Abnormal PFA-100 testLow factor VIII levels (if low a factor VIII/VWF binding assay is performed)Prolonged APTT (or normal)Normal PTLow VWF levelsDefective platelet aggregationNormal platelet count
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This question is part of the following fields:
- Haematology
- Pathology
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Question 25
Incorrect
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Regarding an avulsion fracture, a sudden contraction of which muscle may lead to fracture of the head of the fibula?
Your Answer:
Correct Answer: Biceps femoris
Explanation:Avulsion fractures of the fibular head are rare and are so-called the arcuate signal. The “arcuate signal” is used to describe an avulsed bone fragment related to the insertion site of the tendon of the biceps femoris associated with the arcuate complex, which consists of the fabellofibular, popliteofibular, and arcuate ligaments. Such lesions are typically observed in direct trauma to the knee with excessive varus and internal rotation forces or indirect trauma with the same direction of the force.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 26
Incorrect
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Which of the following is NOT a characteristic of megaloblastic anaemia?
Your Answer:
Correct Answer: Raised reticulocyte count
Explanation:The LDH level is usually markedly increased in severe megaloblastic anaemia. Reticulocyte counts are inappropriately low, representing a lack of production of RBCs due to massive intramedullary haemolysis. These findings are characteristics of ineffective haematopoiesis that occurs in megaloblastic anaemia as well as in other disorders such as thalassemia major.The common feature in megaloblastosis is a defect in DNA synthesis in rapidly dividing cells. To a lesser extent, RNA and protein synthesis are impaired. Unbalanced cell growth and impaired cell division occur since nuclear maturation is arrested. More mature RBC precursors are destroyed in the bone marrow prior to entering the bloodstream (intramedullary haemolysis).
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This question is part of the following fields:
- Haematology
- Pathology
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Question 27
Incorrect
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The Frank-Starling curve is shifted downhill in heart failure due to which of the following?
Your Answer:
Correct Answer: Decrease in contractility
Explanation:The Frank–Starling mechanism states that the left ventricle can increase its force of contraction and hence stroke volume in response to increases in venous return and thus preload. Changes in afterload or inotropy cause the Frank–Starling curve to rise or fall. In heart failure, the Frank–Starling curve is shifted downward (flattened), requiring higher venous return and filling pressure to enhance contractility and stroke volume.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 28
Incorrect
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An 18-year-old student presents with a 1-week history of sore throat, low grade fever, and malaise. Upon history taking, she noted that she had a fine rash over her body a week ago that quickly fades. Further examination and observation was done and the presence of mild splenomegaly was noted. Her test shows positive for heterophile antibody test, suspecting a diagnosis of infectious mononucleosis.Which of the following characteristics is mostly associated with the diagnosis of infectious mononucleosis?
Your Answer:
Correct Answer: Atypical lymphocytes
Explanation: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.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 29
Incorrect
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The results from the study investigating the accuracy of a new diagnostic test can be displayed in the following format. How is the positive predictive value calculated:Those with diseaseThose without diseaseTotalTest positiveaba+bTest negativecdc+dTotala+cb+dn=a+b+c+d
Your Answer:
Correct Answer: a/(a+b)
Explanation:Positive predictive value (PPV) is the proportion of individuals with a positive test result who actually have the disease.PPV = a/(a+b)
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 30
Incorrect
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A 54-year-old woman has been visiting her GP with symptoms of tiredness, muscle weakness and headaches. She is known to be hypertensive and takes amlodipine to control this. Her blood results today show that her potassium level is low at 3.0 mmol/L, and her sodium level is slightly elevated at 146 mmol/L.Which of the following is the SINGLE most appropriate INITIAL investigation?
Your Answer:
Correct Answer: Plasma renin and aldosterone levels
Explanation:Primary hyperaldosteronism occurs when there are excessive levels of aldosterone independent of the renin-angiotensin axis. Secondary hyperaldosteronism occurs due to high renin levels.The causes of primary hyperaldosteronism include:Adrenal adenoma (Conn’s syndrome) – the most common cause of hyperaldosteronism (,80% of all cases). These are usually unilateral and solitary and are more common in women.Adrenal hyperplasia – this accounts for ,15% of all cases. Usually, bilateral adrenal hyperplasia (BAH) but can be unilateral rarely. More common in men than women.Adrenal cancer – a rare diagnosis but essential not to missFamilial aldosteronism – a rare group of inherited conditions affecting the adrenal glandsThe causes of secondary hyperaldosteronism include:Drugs – diureticsObstructive renal artery disease – renal artery stenosis and atheromaRenal vasoconstriction – occurs in accelerated hypertensionOedematous disorders – heart failure, cirrhosis and nephrotic syndromePatients are often asymptomatic. When clinical features are present, the classically described presentation of hyperaldosteronism is with:HypertensionHypokalaemiaMetabolic alkalosisSodium levels can be normal or slightly raisedOther, less common, clinical features include:LethargyHeadachesMuscle weakness (from persistent hypokalaemia)Polyuria and polydipsiaIntermittent paraesthesiaTetany and paralysis (rare)Often the earliest sign of hyperaldosteronism is from aberrant urea and electrolytes showing hypokalaemia and mild hypernatraemia. If the patient is taking diuretics, and the diagnosis is suspected, these should be repeated after the patient has taken off diuretics.If the diagnosis is suspected, plasma renin and aldosterone levels should be checked. Low renin and high aldosterone levels (with a raised aldosterone: renin ratio) is suggestive of primary aldosteronism.If the renin: aldosterone ratio is high, then the effect of posture on renin, aldosterone and cortisol can be investigated to provide further information about the underlying cause of primary hyperaldosteronism. Levels should be measured lying at 9 am and standing at noon:If aldosterone and cortisol levels fall on standing, this is suggestive of an ACTH dependent cause, e.g. adrenal adenoma (Conn’s syndrome)If aldosterone levels rise and cortisol levels fall on standing, this is suggestive of an angiotensin-II dependent cause, e.g. BAHOther investigations that can help to distinguish between an adrenal adenoma and adrenal hyperplasia include:CT scanMRI scanSelective adrenal venous sampling
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
