-
Question 1
Correct
-
A 6 year old boy is brought into the ED by his mom with a rash that is associated with Koplik's spots and a diagnosis of measles is made. What advice should be given about returning to school?
Your Answer: 4 days from the onset of the rash
Explanation:Prevention of spread of measles is extremely important and infected patients should be isolated. The infectious stage is from 3 days before the rash emerges and patients are advised to stay away from school/nursery/work for 4 days from onset of the rash.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 2
Incorrect
-
A patient who has a nerve injury has sparing of the upper half of the orbicularis oculi muscle but not the lower half. Which branch of the facial nerve supplies the lower half of the orbicularis oculi?
Your Answer: Temporal branch
Correct Answer: Zygomatic branch
Explanation:The facial nerve divides into five terminal branches once in the parotid gland. 1. The temporal branch innervates muscles in the temple, forehead and supraorbital areas.2. The zygomatic branch innervates muscles in the infraorbital area, the lateral nasal area and the upper lip.3. The buccal branch innervates muscles in the cheek, the upper lip and the corner of the mouth. 4. The marginal mandibular branch innervates muscles of the lower lip and chin. 5. The cervical branch innervates the platysma muscle.
-
This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
-
-
Question 3
Incorrect
-
Which of the following microbes binds strongly to CD4 antigen:
Your Answer: Epstein-Barr virus
Correct Answer: HIV
Explanation:HIV mainly infects CD4+ T helper cells. Viral replication results in progressive T-cell depletion and impaired cell-mediated immunity with subsequent secondary opportunistic infections and increased risk of malignancy. B-cell function is also reduced as a result of lack of T-cell stimulation.HIV is not a notifiable disease.
-
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 4
Correct
-
Cryptococcus neoformans is primarily transmitted by which of the following routes:
Your Answer: Inhalation of spores
Explanation:Cryptococcus neoformans is found in bird droppings and transmission is by inhalation of spores, thus the lung is the primary site of infection.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 5
Correct
-
The most important nerve for plantar flexion of the foot at the ankle joint is:
Your Answer: Tibial nerve
Explanation:Muscles of the posterior compartment of the leg, innervated by the tibial nerve, perform plantar flexion of the foot at the ankle joint. The fibularis longus (innervated by the superficial fibular nerve) assists in plantar flexion but is not the most important.
-
This question is part of the following fields:
- Anatomy
- Lower Limb
-
-
Question 6
Correct
-
What is the mechanism of action of captopril:
Your Answer: Angiotensin-converting enzyme inhibitor
Explanation:Captopril is an angiotensin-converting enzyme (ACE) inhibitor, which inhibits the conversion of angiotensin I to angiotensin II.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 7
Correct
-
A 29-year-old female with chronic anaemia secondary to sickle cell disease is being transfused. A few minutes after starting the blood transfusion, she develops widespread itching with urticarial rash, wheezing, nausea and chest pain. Her BP reduces to 60/40 mmHg.What is the most appropriate treatment?
Your Answer: Stop the transfusion and administer adrenaline
Explanation:Anaphylaxis transfusion reaction occurs when an individual has previously been sensitized to an allergen present in the blood and, on re-exposure, releases IgE or IgG antibodies. Patients with anaphylaxis usually develop laryngospasm, bronchospasm, abdominal pain, nausea, vomiting, hypotension, shock, and loss of consciousness. The transfusion should be stopped immediately and the patient should be treated with adrenaline, oxygen, corticosteroids, and antihistamines.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 8
Correct
-
You are attending to a patient that has presented with a severe headache in the Emergency Department. The patient has signs of cerebral oedema and raised intracranial pressure. You discuss the case with the on-call neurology registrar and decide to prescribe Mannitol. The nurse assisting you asks you to reconsider this management plan as she suspects the patient has a contraindication to Mannitol.Out of the following, what is a contraindication to mannitol?
Your Answer: Severe cardiac failure
Explanation:Mannitol is the most widely used osmotic diuretic that is most commonly used to reduce cerebral oedema and intracranial pressure. It is recommended to use mannitol for the reduction of CSF pressure/cerebral oedema in a dose of 0.25-2 g/kg as an intravenous infusion over 30-60 minutes. This can be repeated 1-2 times after 4-8 hours if needed.Mannitol has several contraindications and some of them are listed below:1. Anuria due to renal disease2. Acute intracranial bleeding (except during craniotomy)3. Severe cardiac failure4. Severe dehydration5. Severe pulmonary oedema or congestion6. Known hypersensitivity to mannitol
-
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
-
-
Question 9
Incorrect
-
Which patients are particularly susceptible to infection with herpes simplex, those with:
Your Answer: Asplenia
Correct Answer: T-cell deficiency
Explanation:Cell-mediated immunity, especially the action of cytotoxic T-cells, is essential in the control of herpesvirus infections and patients with T-cell deficiency are at particular risk of reactivation and severe infection. T-cell deficiency may follow HIV infection, chemotherapy, corticosteroid therapy or organ transplantation.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 10
Incorrect
-
Many of the chemical digestion and absorption takes place in the small intestine. Most digestive enzymes in the small intestine are secreted by the pancreas and enter the small intestine through the pancreatic duct.Which of these digestive enzymes is responsible for breaking down carbohydrates into monosaccharides?
Your Answer:
Correct Answer: Glucoamylase
Explanation:Majority of carbohydrates are broken down into monosaccharides (glucose, fructose galactose) and are absorbed by the small intestine. Enzymes released from the brush border break down carbohydrate. Some carbohydrates, such as cellulose, are not digested at all, despite being made of multiple glucose units. This is because the cellulose is made out of beta-glucose that makes the inter-monosaccharide bindings different from the ones present in starch, which consists of alpha-glucose. Humans lack the enzyme for splitting the beta-glucose-bond.The principal brush border enzymes are dextranase and glucoamylase. Other brush border enzymes are maltase, sucrase, and lactase.Pancreatic amylase breaks down some carbohydrates (notably starch) into oligosaccharides. Dextranase and glucoamylase, then further break down oligosaccharides.Trypsin aids in digestion of protein.Chymotrypsin is a proteolytic enzyme that digests proteinCarboxypeptidase hydrolyses the first peptide or amide bond at the carboxyl or C-terminal end of proteins and peptides
-
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
-
-
Question 11
Incorrect
-
After collapsing in his nursing home, a 70-year-old man is brought into the ER. He is a known case of diabetes mellitus and is on medication for it. An RBS of 2.5 mmol/L (3.9-5.5 mmol/L) is recorded in the ER. Out of the following, which medication for diabetes mellitus is MOST likely responsible for his hypoglycaemic episode?
Your Answer:
Correct Answer: Pioglitazone
Explanation:Pioglitazone is used to treat type 2 diabetes mellitus. It selectively stimulates the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ) and to a lesser extent PPAR-α. Of the medications mentioned in this question, only pioglitazone is a recognized cause of hypoglycaemia.
-
This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
-
-
Question 12
Incorrect
-
Which one of these infectious diseases typically has an incubation period of between 1 and 3 weeks?
Your Answer:
Correct Answer: Chickenpox
Explanation:The incubation period for Chickenpox is 7-23 days (usually around 2 weeks).Incubation period of botulism is 18-36 hoursIncubation period of Meningococcaemia is 1-7 days.Incubation period of Gonorrhoea is 3-5 days.Incubation period of Hepatitis A is 3-5 weeks.Other infectious with an incubation period of between 1 and 3 weeks are:Whooping cough (7-10 days)Brucellosis (7-21 days)Leptospirosis (7-12 days)Malaria (7-40 days depending on strain)Typhoid (8-21 days)Measles (10-18 days)Mumps (14-18 days)Rubella (14-21 days)
-
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
-
-
Question 13
Incorrect
-
Identify the type of graph described below:This graph is a scatter plot of the effect estimates from individual studies against some measure of each study's size or precision.
Your Answer:
Correct Answer: Funnel plot
Explanation:A funnel plot is a scatter plot of the effect estimates from individual studies against some measure of each study’s size or precision. The standard error of the effect estimate is often chosen as the measure of study size and plotted on the vertical axis with a reversed scale that places the larger, most powerful studies towards the top. The effect estimates from smaller studies should scatter more widely at the bottom, with the spread narrowing among larger studies. In the absence of bias and between study heterogeneity, the scatter will be due to sampling variation alone and the plot will resemble a symmetrical inverted funnel. A triangle centred on a fixed effect summary estimate and extending 1.96 standard errors either side will include about 95% of studies if no bias is present and the fixed effect assumption (that the true treatment effect is the same in each study) is valid.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 14
Incorrect
-
Cefotaxime (or ceftriaxone) is used first line for which of the following infections:
Your Answer:
Correct Answer: Blind treatment of suspected bacterial meningitis
Explanation:Cefotaxime (or ceftriaxone) are indicated first line in:- Blind treatment of meningitis in patients > 3 months (with amoxicillin if patient > 50 years)- Meningitis caused by meningococci- Meningitis caused by pneumococci- Meningitis caused by H. influenzae- Severe or invasive salmonellosis- Typhoid fever- Gonorrhoea- Gonococcal arthritis- Haemophilus influenzae epiglottitis
-
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 15
Incorrect
-
A 79-year-old male had a humeral shaft fracture during a road traffic accident and is being followed up in a fracture clinic. He complains of inability to use the limb 6 months after the injury. X-rays of that arm shows non union of his fracture.All the following are responsible for this non-union EXCEPT?
Your Answer:
Correct Answer: Osteoporosis
Explanation:An imbalance between bone resorption and formation is Osteoporosis. In normal bone, formation and resorption are roughly equal, and the density of bone matrix remains constant but there is more resorption in osteoporosis and the matrix density reduces and bones become weaker. Fractures are more likely to occur but healing is unaffected. Non-union of a fracture occurs when the two sides of a fracture fail to unite after 6 months. Causes include: infection, movement at the fracture site, avascular necrosis, tissue interposed between the fracture and gross misalignment.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 16
Incorrect
-
An analytical study is conducted to compare the risk of stroke between Ticagrelor therapy and Warfarin therapy among patients with atrial fibrillation. The following is obtained from the study:No. of patients who took Ticagrelor: 300No. of patients who took Ticagrelor and suffered a stroke: 30No. of patients who took Warfarin: 500No. of patients who took Warfarin and suffered a stroke: 20Compute for the absolute risk in the Ticagrelor group.
Your Answer:
Correct Answer: 0.1
Explanation:The absolute risk (AR) is the probability or chance of an event. It is computed as the number of events in treated or control groups, divided by the number of people in that group.AR = 30/300 = 0.1
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 17
Incorrect
-
Regarding the routine childhood immunisation schedule, which of the following vaccines is given to preschool children (aged 3 years and 4 months):
Your Answer:
Correct Answer: Measles, mumps and rubella (MMR)
Explanation:The current UK childhood immunisation schedule is as follows:8 weeks:DTaP/IPV(polio)/Hib/Hep B (diptheria, tetanus, pertussis, polio,Haemophilus influenzatype b and hepatitis B) – 6-in-one injection (Infranix hexa);plus:Rotavirus gastroenteritis (Rotarix) – oral route (drops)Meningitis B (Bexsero)12 weeks:DTaP/IPV(polio)/Hib/Hep B – 2nddose: 6-in-one injection, 2nddose (Infranix hexa);plus:PCV (pneumococcal conjugate vaccine) – in a separate injection (Prevenar 13)Rotavirus gastroenteritis 2nddose (Rotarix) – oral route (drops)16 weeks:DTaP/IPV(polio)/Hib/Hep B – 3rddose: 6-in-one injection, 3rddose (Infranix hexa);plus:Meningitis B 2nddose (Bexsero)Between 12 and 13 months:Hib/Men C (combined as one injection) – 4th dose of Hib and 1stdose of Meningitis C (Menitorix);plus:MMR (measles, mumps and rubella) – combined as one injection (Priorix or M-M-RVAXPRO);plus:PCV (pneumococcal conjugate vaccine) – 2nddose in a separate injection (Prevenar 13);plus:Meningitis B 3rddose (Bexsero)From 2 to end of primary school:Nasal flu spray (Fluenz Tetra). For children aged 2,3 and 4, this is usually given in the GP surgery. Children in school years 1,2 and 3 may have this at school.3 years and 4 months:Pre-school booster of DTaP/IPV (polio) – 4-in-one injection (Repevax or Infanrix-IPV);plus:MMR – 2nd dose (Priorix or M-M-RVAXPRO) – in a separate injectionBetween 12 and 13 years:HPV (human papilloma virus types 6,11, 16 and 18) –twoinjections of Gardasil given. The second injection is given 6-24 months after the first one.14 years:Td/IPV (polio) booster – 3-in-one injection (Revaxis)Men ACWY: combined protection against meningitis A, C, W and Y (Nimenrix or Menveo)The BCG vaccination against tuberculosis is only offered to neonates in high-risk areas or with high-risk backgrounds. When required it is usually given before leaving the hospital soon after birth.
-
This question is part of the following fields:
- Immunoglobulins And Vaccines
- Pharmacology
-
-
Question 18
Incorrect
-
Dexamethasone would be most useful for which of the following conditions:
Your Answer:
Correct Answer: Raised intracranial pressure secondary to malignancy
Explanation:Dexamethasone has a very high glucocorticoid activity in conjunction with insignificant mineralocorticoid activity. This makes it particularly suitable for high-dose therapy in conditions where fluid retention would be a disadvantage such as in the management of raised intracranial pressure or cerebral oedema secondary to malignancy. Dexamethasone also has a long duration of action and this, coupled with its lack of mineralocorticoid action makes it particularly suitable for suppression of corticotropin secretion in congenital adrenal hyperplasia. In most individuals a single dose of dexamethasone at night, is sufficient to inhibit corticotropin secretion for 24 hours. This is the basis of the ‘overnight dexamethasone suppression test’ for diagnosing Cushing’s syndrome.
-
This question is part of the following fields:
- Endocrine
- Pharmacology
-
-
Question 19
Incorrect
-
Which of the following ions normally has the highest concentration in intracellular fluid:
Your Answer:
Correct Answer: K +
Explanation:Potassium (K+) is the principal intracellular ion; approximately 4 mmol/L is extracellular (3%) and 140 mmol/L intracellular (97%).
-
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 20
Incorrect
-
A 40-year-old man with reduced urine output, nausea, and confusion also has a 150% rise of creatinine from baseline over the past 7 days. A diagnosis of acute kidney injury (AKI) is made after more tests are done.His AKI stage is?
Your Answer:
Correct Answer: Stage 2
Explanation:This patient with a 150% rise of creatinine above baseline within 7 days has stage 2 Acute kidney injury (AKI).AKI stages are as follows:Stage 1Creatinine rise of 26 micromole/L or more within 48 hours, orCreatinine rise of 50-99% from baseline within 7 days (1.5-1.99 x baseline),orUrine output <0.5 mL/kg/hour for more than 6 hoursStage 2Creatinine rise of 100-199% from baseline within 7 days (2.0-2.99 x baseline),orUrine output <0.5 mL/kg/hour for more than 12 hoursStage 3Creatinine rise of 200% or more from baseline within 7 days (3.0 or more x baseline), orCreatinine rise to 354 micromole/L or more with acute rise of 26 micromole/L or more within 48 hours or 50% or more rise within 7 days, orUrine output <0.3 mL/kg/hour for 24 hours or anuria for 12 hours
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 21
Incorrect
-
Which of the following statements about sickle cell disease is TRUE:
Your Answer:
Correct Answer: Hand-foot syndrome is frequently a first presentation of the disease.
Explanation:Hand-foot syndrome in children is typically the first symptom of the disease, produced by infarction of the metaphysis of small bones. The disease is inherited as an autosomal recessive trait. By adulthood, the spleen has usually infarcted. Infection with the B19 parvovirus is usually followed by an aplastic crisis. Thrombocytopenia is caused by splenic sequestration.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 22
Incorrect
-
Intrinsic factor is secreted by which of the following cell types in the stomach:
Your Answer:
Correct Answer: Parietal cells
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.
-
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
-
Question 23
Incorrect
-
Which segment of the colon is most likely to be affected in diverticulitis?
Your Answer:
Correct Answer: Sigmoid colon
Explanation:Diverticulitis refers to inflammation and infection associated with a diverticulum and is estimated to occur in 10% to 25% of people with diverticulosis. Peridiverticular and pericolic infection results from a perforation (either macroscopic or microscopic) of a diverticulum, which leads to contamination, inflammation, and infection. The spectrum of disease ranges from mild, uncomplicated diverticulitis that can be treated in the outpatient setting, to free perforation and diffuse peritonitis that requires emergency laparotomy. Most patients present with left sided abdominal pain, with or without fever, and leucocytosis. The most common location for diverticulitis is the sigmoid colon.
-
This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
-
-
Question 24
Incorrect
-
Regarding bile acids, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: The main primary bile acids are deoxycholic acid and lithocholic acid.
Explanation:Bile acids have a hydrophobic and a hydrophilic end and in aqueous solution, bile salts orient themselves around droplets of lipid forming micelles to keep the lipid droplets dispersed. The principal primary bile acids are cholic acid and chenodeoxycholic acid. They are made more soluble by conjugation with taurine or glycine in the liver. Of the bile acids excreted into the intestine, about 95% are reabsorbed into the portal circulation by active transport mechanisms in the distal ileum and recycled by the liver.
-
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
-
Question 25
Incorrect
-
Following an injury sustained during a rugby match, a 16-year-old boy is brought to the Emergency Department by his mother. His forearm appears to be deformed, and you believe he has a distal radius fracture. A numerical rating scale is used to assess his pain, and the triage nurse informs you that he is in moderate pain.'The RCEM guidance recommends which of the following analgesics for the treatment of moderate pain in a child of this age?
Your Answer:
Correct Answer: Oral codeine phosphate 1 mg/kg
Explanation:According to a 2018 audit conducted by the Royal College of Emergency Medicine (RCEM), the standard of care for children presenting to EDs with fractured limbs has deteriorated, with most patients waiting longer than ever before for pain relief. More than one-tenth of the children who came in with significant pain from a limb fracture received no pain relief at all.For all patients, including children, the Agency for Health Care Policy and Research (AHCPR) in the United States recommends using the ABCs of pain management:A – Ask about pain regularly. Assess pain systematically.B – Believe the patient and family in their reports of pain and what relieves it.C – Choose pain control options appropriate for the patient, family, and setting.D – Deliver interventions in a timely, logical, coordinated fashion.E – Empower patients and their families. Enable patients to control their course to the greatest extent possible.The RCEM guidelines recommend assessing a child’s pain within 15 minutes of arrival. This is a fundamental requirement. For the assessment of pain in children, a variety of rating scales are available; which one is used depends on the child’s age and ability to use the scale. These are some of them:Faces of Wong-Baker Scale for assessing painScale of numerical evaluationThe behavioural scale is a scale that measures how people behave.The RCEM has provided the following visual guide:The RCEM has established the following guidelines for when patients in severe pain should receive appropriate analgesia:100% within 60 minutes of arrival or triage, whichever is earliest75% within 30 minutes of arrival or triage, whichever is earliest50% within 20 minutes of arrival or triage, whichever is earliest
-
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
-
-
Question 26
Incorrect
-
An 82 year old man taking warfarin as a maintenance medication comes in to your clinic because of an infection. Which antibiotic is the safest choice for this patient?
Your Answer:
Correct Answer: Cefalexin
Explanation:Alterations in the international normalized ratio (INR) brought about by the concurrent use of antibiotics and warfarin may result in either excessive clotting or excessive bleeding if they are deemed to have a high risk for interaction. As such, there should be careful consideration of the class of antibiotic to be used. Antibiotics from the following drug classes should generally be avoided as they have a high risk for interaction with warfarin, possible enhancing the anticoagulant effects of warfarin resulting in bleeding: Fluoroquinolones (e.g. ciprofloxacin, levofloxacin), Macrolides (e.g. clarithromycin, erythromycin, azithromycin), Nitroimidazoles (e.g. metronidazole), Sulphonamides (e.g. co-trimoxazole, a combination of trimethoprim and sulfamethoxazole), Trimethoprim, Tetracyclines (e.g. doxycycline). Low risk antibiotics that have low risk for interaction with warfarin includes cephalexin, from the cephalosporin class, and clindamycin which is a lincomycin.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 27
Incorrect
-
A 50-year-old woman with painful joints had some blood tests done with her GP. The test showed she had anti-double stranded DNA antibodies.Which one of these disorders is most likely to be associated with anti-double stranded DNA antibodies?
Your Answer:
Correct Answer: Systemic lupus erythematosus (SLE)
Explanation:CREST syndrome is usually associated with anti-centromere antibodies.Primary biliary cirrhosis is associated with anti-mitochondrial antibodies.Sjogren’s syndrome is associated with anti-Ro and anti-La antibodies.Polymyositis is associated with anti-Jo1 antibodies.Anti-double stranded DNA antibodies are highly characteristic of systemic lupus erythematosus (SLE). They are a group of anti-nuclear antibodies (ANA) that target double stranded DNA and are implicated in the pathogenesis of lupus nephritis.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 28
Incorrect
-
A 58-year-old man showing symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that he has a full, plethoric aspect to his face, as well as significant supraclavicular fat pads, when you examine him. His blood pressure is 158/942 mmHg, and his glucose tolerance has lately been impaired. His potassium level is 3.2 mmol/L.What is the MOST LIKELY diagnosis?
Your Answer:
Correct Answer: Cushing’s syndrome
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.Cushing’s syndrome has a wide range of clinical manifestations that are dependent on the degree of cortisol overproduction. The appearance might be vague and the diagnosis difficult to detect when cortisol levels are just somewhat elevated. On the other hand, in long-term cases of severely increased cortisol levels, the presentation might be colourful and the diagnosis simple.Cushing’s syndrome has the following clinical features:Obesity and weight growth in the true senseSupraclavicular fat pads are fat pads that are located above the clavicle.Buffalo humpFullness and plethora of the face (‘moon facies’)Muscle atrophy and weakening at the proximal levelDiabetes mellitus, also known as impaired glucose toleranceHypertensionSkin thinning and bruisingDepressionHirsutismAcneOsteoporosisAmenorrhoea or oligomenorrhoeaCortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep. The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater during the whole 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed. As a result, random cortisol testing is not an effective screening technique and is not advised.The following are the two most common first-line screening tests:Cortisol levels in the urine are measured every 24 hours.A diagnosis of Cushing’s syndrome can be made if more than two collections measure cortisol excretion more than three times the upper limit of normal.Physical stress (e.g., excessive exercise, trauma), mental stress (e.g., sadness), alcohol or drug misuse, complex diabetes, and pregnancy can all cause false positives.Renal dysfunction, inadequate collection, and cyclical Cushing’s disease can all cause false negatives.The overnight low-dose dexamethasone suppression test (LDDST) involves giving 1 mg of dexamethasone at 11 p.m. and measuring blood cortisol levels at 8 a.m. the next day.Cushing’s syndrome is diagnosed when cortisol is not suppressed to less than 50 nmol/L.It might be difficult to tell the difference between mild Cushing’s disease and normal cortisol production.False positives can occur as a result of depression, severe systemic sickness, renal failure, prolonged alcohol misuse, old age, and the use of hepatic enzyme-inducing medicines, among other things.False negatives are extremely uncommon in Cushing’s disease patients.A characteristic biochemical picture might also be helpful in confirming the diagnosis of Cushing’s syndrome. The following are the primary characteristics:HypokalaemiaAlkalosis metabolique
-
This question is part of the following fields:
- Endocrine Physiology
- Physiology
-
-
Question 29
Incorrect
-
Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Metronidazole is usually the antibiotic of choice for tetanus infection.
Explanation:Clostridium tetani infection is predominantly derived from animal faeces and soil. Clostridium tetani has exotoxin-mediated effects, predominantly by tetanospasmin which inhibits the release of GABA at the presynaptic membrane throughout the central and peripheral nervous system. Metronidazole has overtaken penicillin as the antibiotic of choice for treatment of tetanus (together with surgical debridement, tetanus toxoid immunisation, and human tetanus immunoglobulin).
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 30
Incorrect
-
Which of the following is a physiological function that is mediated by a hormone released by the posterior pituitary:
Your Answer:
Correct Answer: Water retention
Explanation:Antidiuretic hormone (ADH), released by the posterior pituitary, acts on the kidneys to increase water permeability in the distal nephron allowing greater water reabsorption and concentration of urine. Prolactin, from the anterior pituitary, is responsible for milk production. The thyroid hormones, from the thyroid gland, are responsible for an increase in basal metabolic rate (stimulated by TSH from the anterior pituitary). FSH/LH, from the anterior pituitary, are responsible for maturation of egg and sperm. Calcitonin, from the thyroid gland, is responsible for decreasing calcium levels.
-
This question is part of the following fields:
- Endocrine
- Physiology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
