-
Question 1
Correct
-
A 10-year-old girl that appears systemically well presents with a honey-crusted scab close to the corner of her mouth and states that the area is slightly itchy but not painful. The diagnosis given was impetigo.
What is most likely the mode of transmission of the causative agent of the said diagnosis?Your Answer: Direct contact
Explanation:Impetigo is a common pyoderma that is most often seen in children. Historically, most cases were caused by group A streptococci (GAS; Streptococcus pyogenes), although S. aureus has become the predominant pathogen over the last 15 years.
A bullous form of impetigo accounts for approximately 10% of cases. It is caused by strains of S. aureus that produce exfoliative toxins leading to the formation of bullae, which quickly rupture and form a transparent, light brown crust.
Impetigo is spread mainly by person-to-person contact; it is rapidly spread through direct transmission. The diagnosis of impetigo can be made from a Gram stain and culture of the vesicular contents.
-
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
-
-
Question 2
Incorrect
-
All of the following statements are considered true regarding likelihood ratios, except:
Your Answer: They provide a way to estimate the pre-test probabilities of having a condition
Correct Answer: A likelihood ratio less than 1 indicates that the result is associated with the presence of the disease
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.
The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.
A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 3
Incorrect
-
A 58-year-old man presented to the emergency room complaining of a chest pain that has been going on for the past 12 hours. Upon further investigation, a troponin test was ordered and the results came back negative. He was given a discharge order from the emergency department.
Which of the following aspects of this test is considered the most significant in the decision made that it was safe to send the patient home?Your Answer: Positive predictive value
Correct Answer: Likelihood ratio
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.
The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.
A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 4
Incorrect
-
In the United Kingdom, which of the following is the most often used intravenous aesthetic:
Your Answer: Thiopental sodium
Correct Answer: Propofol
Explanation:In the United Kingdom, propofol is the most widely used intravenous anaesthetic. In adults and children, it can be used to induce or maintain anaesthesia, although it is not commonly used in newborns. It can also be used to sedate individuals in intensive care and for sedation during operations.
-
This question is part of the following fields:
- Anaesthesia
- Pharmacology
-
-
Question 5
Incorrect
-
A patient suffered from a chest injury while working out in the gym. As a consequence of his injury, his pectoralis minor muscle was damaged.
Which of the following statements regarding the pectoralis minor muscle is considered correct?Your Answer: It is innervated by the long thoracic nerve
Correct Answer: It stabilises the scapula
Explanation:The pectoralis minor, in comparison to the pectoralis major, is much thinner and triangular in shape and resides below the major. It originates from the margins of the third to fifth ribs adjacent to the costochondral junction. The fibres consequently pass upward and laterally to insert into the medial border and superior surface of the coracoid process. It is crucial in the stabilization of the scapula by pulling it downward and anteriorly against the thoracic wall.
Arterial supply to the pectoralis minor also derives from the pectoral branch of the thoracoacromial trunk. Nerve supply of the pectoralis minor is a function of the lateral pectoral nerve and the medial pectoral nerve.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 6
Correct
-
C5 - C9 deficiency increases susceptibility to infection with which of the following:
Your Answer: Neisseria spp.
Explanation:If the complement sequence is completed, an active phospholipase (the membrane attack complex, MAC) is produced, which punches holes in the cell membrane and causes cell lysis. Because the MAC appears to be the sole means to destroy the Neisseria family of bacteria, C5 – C9 deficiency increases susceptibility to Neisseria infections.
-
This question is part of the following fields:
- Immune Responses
- Pathology
-
-
Question 7
Incorrect
-
Which of the following nerves supplies innervation to the extensor hallucis longus?
Your Answer: Tibial nerve
Correct Answer: Deep peroneal nerve
Explanation:Extensor hallucis longus is innervated by the deep fibular nerve (root value L5 and S1).
-
This question is part of the following fields:
- Anatomy
- Lower Limb
-
-
Question 8
Correct
-
Which of the following does NOT predispose to digoxin toxicity in a patient taking digoxin:
Your Answer: Hyponatraemia
Explanation:Hypoxia, hypercalcaemia, hypokalaemia and hypomagnesaemia predispose to digoxin toxicity. Care should also be taken in the elderly who are particularly susceptible to digoxin toxicity. Hypokalaemia may be precipitated by use of diuretics. Although hyponatremia can result in the development of other pathological disturbances, it does not potentiate digoxin toxicity.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 9
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: Pancreatic amylase
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 protein
Carboxypeptidase 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 10
Incorrect
-
An 82 year old man has fever, left sided abdominal and back pain and presents to the emergency room. Imaging reveals a large perinephric abscess. Which of the following most likely describes the fluid location:
Your Answer: Between the renal fascia and the paranephric fat
Correct Answer: Between the renal capsule and the renal fascia
Explanation:The perinephric fat is immediately external to the renal capsule and completely surrounds the kidney. The renal fascia surrounds the perinephric fat and the paranephric fat is external to the renal fascia. The location of a perinephric abscess is in the perinephric fat between the renal capsule and the renal fascia.
-
This question is part of the following fields:
- Abdomen
- Anatomy
-
-
Question 11
Incorrect
-
A 22-year-old man arrives at the emergency department with a sore throat, low-grade fever, and malaise. His partner has infectious mononucleosis, which was recently diagnosed. In this situation, which of the following cells is the most proliferative:
Your Answer: Neutrophils
Correct Answer: Lymphocytes
Explanation:Histologic findings in EBV infectious mononucleosis: Oropharyngeal epithelium demonstrates an intense lymphoproliferative response in the cells of the oropharynx. The lymph nodes and spleen show lymphocytic infiltration primarily in the periphery of a lymph node.
Relative lymphocytosis (≥ 60%) plus atypical lymphocytosis (≥ 10%) are the characteristic findings of Epstein Barr virus (EBV) infectious mononucleosis. -
This question is part of the following fields:
- Immune Responses
- Pathology
-
-
Question 12
Incorrect
-
You examine a patient's blood tests and discover that her electrolyte levels are abnormal.
Which of the following is the major extracellular cation?Your Answer: Chloride
Correct Answer: Sodium
Explanation:Electrolytes are compounds that may conduct an electrical current and dissociate in solution. Extracellular and intracellular fluids contain these chemicals. The predominant cation in extracellular fluid is sodium, whereas the major anion is chloride. Potassium is the most abundant cation in the intracellular fluid, while phosphate is the most abundant anion. These electrolytes are necessary for homeostasis to be maintained.
-
This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
-
-
Question 13
Incorrect
-
You see a 63-year-old man with a history of melaena and epigastric discomfort. For a few months, he's been taking aspirin.
Which of the following statements about aspirin's mechanism of action is correct?Your Answer: COX-1 inhibition is primarily responsible for its anti-inflammatory effects
Correct Answer: It inhibits both COX-1 and COX-2 at medium to high doses (500-5000 mg per day)
Explanation:Aspirin inhibits cyclo-oxygenase irreversibly by covalently acetylating the cyclo-oxygenase active site in both COX-1 and COX-2. The production of prostaglandin and thromboxane is reduced as a result. As a result, platelet activation and aggregation are reduced. A single dose of aspirin has a half-life of 7-10 days, which is the time it takes for the bone marrow to produce new platelets.
Aspirin only inhibits COX-1, the enzyme that produces thromboxane A2, at low doses (75 mg per day), and thus has a primarily anti-thrombotic effect.
Aspirin inhibits both COX-1 and COX-2 at medium to high doses (500-5000 mg per day). COX-2 is involved in the production of prostaglandins, so it has an anti-inflammatory effect at these concentrations.
Aspirin, when used as an antipyretic for a viral illness in children, can cause Reye’s syndrome. Reye’s syndrome is a potentially fatal liver disease that causes encephalopathy and liver failure.
The inability of aspirin to reduce platelet production of thromboxane A2, and thus platelet activation and aggregation, is known as aspirin resistance. Although the exact frequency and mechanism of aspirin resistance are unknown, it is thought to affect about 1% of users. Women are more likely than men to experience this phenomenon.
According to new research, taking aspirin on a regular basis lowers the risk of colorectal cancer. It may also protect against cancers of the breast, bladder, prostate, and lungs.
-
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
-
-
Question 14
Incorrect
-
In the small intestine, there is a deep gap between each villus that leads to the crypt of Lieberkühn, a tubular intestinal gland.
What is the primary function of these glands?
Your Answer: Secretion of secretin
Correct Answer: Production of an alkaline intestinal juice
Explanation:In the small intestine, there is a deep gap between each villus that leads to the crypt of Lieberkühn, a tubular intestinal gland. These glands create an alkaline intestinal juice that is a mixture of water and mucus with a pH of 7.4-7.8. Intestinal juice is released in a volume of 1-2 litres per day in response to distention of the small intestine or the irritating effects of chyme on the intestinal mucosa.
-
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
-
-
Question 15
Correct
-
Which of the following is NOT a function of bile:
Your Answer: Digestion of fats into monoglycerides and fatty acids.
Explanation:Bile functions to eliminate endogenous and exogenous substances from the liver (including bilirubin), to neutralise gastric acid in the small intestine, and to emulsify fats in the small intestine and facilitate their digestion and absorption. Bile salts also act as bactericides, destroying many of the microbes that may be present in the food. Bile doesn’t contain digestive enzymes for digestion of lipids into monoglycerides and fatty acids; this is performed mainly by pancreatic lipase.
-
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
-
Question 16
Incorrect
-
A 15-year-old male is admitted to a rehabilitation centre with a history of multiple strokes, myopathy and learning disabilities since childhood. He is under the care of a multidisciplinary team, and his genetic testing reports show the presence of a mitochondrial disorder.
Which one of the following diseases does this patient most likely have?Your Answer: Glucose-6-phosphate dehydrogenase deficiency
Correct Answer: MELAS
Explanation:Mitochondrial diseases are a group of disorders caused by dysfunctional mitochondria. Most cases are maternally inherited, as we inherit our mitochondrial DNA from our mothers only, although mutations in nuclear DNA cause some cases.
Examples of Mitochondrial Diseases include:
1. Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS)
2. Mitochondrial epilepsy with ragged red fibres (MERRF)
3. Leber’s hereditary optic neuropathy (LHON)
4. Diabetes mellitus and deafness (DAD)
5. Neuropathy, ataxia, retinitis pigmentosa, and ptosis (NARP)
6. Leigh syndrome (subacute sclerosing encephalopathy).Red-green colour blindness and G6PD deficiency have an X-linked recessive pattern of inheritance.
Tay-Sachs Disease and spinal muscular atrophy have an autosomal recessive pattern of inheritance.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 17
Incorrect
-
A dermatological examination on a patient presenting with a skin lesion which shows a solid, well circumscribed, lump measuring 0.8 cm in diameter. Which one of these best describes the lump you have found on examination?
Your Answer: Macule
Correct Answer: Papule
Explanation:Macule— a small patch of skin that is altered in colour, but is not elevated.
Patch — a large area of colour change, with a smooth surface.
Papule— elevated, solid, palpable lesion that is ≤ 1 cm in diameter. They may be solitary or multiple. Papules may be:
Nodule — elevated, solid, palpable lesion > 1 cm usually located primarily in the dermis and subcutis (deeper layers of the skin). The greatest portion of the lesion may be above or beneath the skin surface.
Vesicle — a small blister. It is a circumscribed lesion ≤ 1 cm in diameter that contains liquid (clear, serous or haemorrhagic).
Cyst — papule or nodule that contains fluid or semi-fluid material so is fluctuant
Plaque — a circumscribed, palpable lesion more than 1 cm in diameter; most plaques are elevated.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 18
Correct
-
You are taking care of a 55-year-old male patient with a direct inguinal hernia. In explaining his hernia, which of the following layers was compromised and had resulted in his condition?
Your Answer: Transversalis fascia
Explanation:Direct inguinal hernias are most often caused by a weakness in the muscles of the abdominal wall that develops over time, or are due to straining or heavy lifting.
A direct inguinal hernia protrudes through the Transversalis fascia.
-
This question is part of the following fields:
- Abdomen
- Anatomy
-
-
Question 19
Incorrect
-
Atracurium is used as a muscle relaxant during endotracheal intubation. This drug’s mechanism of action is best described by which of the following?
Your Answer: NMDA receptor antagonist
Correct Answer: Nicotinic acetylcholine receptor antagonist
Explanation:Atracurium is a non-depolarizing neuromuscular blocker that is used to help with intubation and controlled ventilation by causing muscle relaxation and paralysis.
At the neuromuscular junction’s post-synaptic membrane, atracurium competes with acetylcholine for nicotinic (N2) receptor binding sites. This prevents the receptors from being stimulated by acetylcholine.
Muscle paralysis occurs gradually due to the competitive blockade.
-
This question is part of the following fields:
- Anaesthesia
- Pharmacology
-
-
Question 20
Correct
-
Regarding bile, which of the following statements is INCORRECT:
Your Answer: The sphincter of Oddi contracts to force bile from the gallbladder into the duodenum.
Explanation:Bile is secreted by hepatocytes. It is isotonic and resembles plasma ionically. This fraction of bile is called the bile acid-dependent fraction. As it passes along the bile duct, the bile is modified by epithelial cells lining the duct by the addition of water and bicarbonate ions; this fraction is called the bile acid-independent fraction. Overall, the liver can produce 500 – 1000 mL of bile per day. The bile is either discharged directly into the duodenum or stored in the gallbladder. The bile acid-independent fraction is made at the time it is required i.e. during digestion of chyme. The bile acid-dependent fraction is made when the bile salts are returned from the GI tract to the liver, and is then stored in the gallbladder until needed. The gallbladder not only stores bile but concentrates it by removing non-essential solutes and water, leaving bile acids and pigments, mainly by active transport of Na+into the intercellular spaces of the lining cells which, in turn, draws in water, HCO3-and Cl-from the bile and into the extracellular fluid. Within a few minutes of a meal, particularly when fatty foods have been consumed, the gallbladder contracts and releases bile into the bile duct. The sphincter of Oddi is relaxed, allowing the bile to pass into the duodenum through the ampulla of Vater.
-
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
