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Question 1
Correct
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Which of the following clinical signs will be demonstrated in a case of Brown-Séquard syndrome due to hemisection of the spinal cord at mid-thoracic level?
Your Answer: Ipsilateral spastic paralysis, ipsilateral loss of vibration and proprioception (position sense) and contralateral loss of pain and temperature sensation beginning one or two segments below the lesion
Explanation:Brown–Séquard syndrome results due to lateral hemisection of the spinal cord and results in a loss of motricity (paralysis and ataxia) and sensation. The hemisection of the cord results in a lesion of each of the three main neural systems: the principal upper motor neurone pathway of the corticospinal tract, one or both dorsal columns and the spinothalamic tract. As a result of the injury to these three main brain pathways the patient will present with three lesions. The corticospinal lesion produces spastic paralysis on the same side of the body (the loss of moderation by the upper motor neurons). The lesion to fasciculus gracilis or fasciculus cuneatus results in ipsilateral loss of vibration and proprioception (position sense). The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion. At the lesion site, all sensory modalities are lost on the same side, and an ipsilateral flaccid paralysis.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 2
Correct
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The renal cortex and medulla, if seen under the microscope, is lacking one of the following:
Your Answer: Squamous epithelium
Explanation:Capillaries, Henle’s loop, collecting ducts, Bertin columns and type IV collagen in glomerular basement membrane are all structures present in the renal cortex or medulla. The squamous epithelium is the only one that is lacking in both the renal cortex and medulla, because normally it is not found above the outer urethra.
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This question is part of the following fields:
- Pathology
- Renal
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Question 3
Correct
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In which of the following conditions will the oxygen-haemoglobin dissociation curve shift to the right?
Your Answer: Exercise
Explanation:The oxygen-haemoglobin dissociation curve plots saturated haemoglobin against the oxygen tension and is usually a sigmoid plot. Each molecule of haemoglobin can bind to four molecules of oxygen reversibly. Factors that can influence the binding include: pH, concentration of 2,3-diphosphoglycerate (2,3-DPG), temperature, type of haemoglobin molecules, and presence of toxins, especially carbon monoxide. Shape of the curve is due to interaction of bound oxygen molecules with the incoming molecules. The binding of first molecule is difficult, with easier binding of the second and third molecule and increase in difficulty with the fourth molecule – partly as a result of crowding and partly as a natural tendency of oxygen to dissociate.
Left shift of curve indicates haemoglobin’s increased affinity for oxygen (seen at lungs). Right shift indicates decreased affinity and is seen with an increase in body temperature, hydrogen ions, 2,3-diphosphoglycerate (DPG), carbon dioxide concentration and exercise. Under normal resting conditions in a healthy individual, the normal position of the curve is at a pH of 7.4. A shift in the position of the curve with a change in pH is called the Bohr effect. Left shift occurs in acute alkalosis, decrease in p(CO2), decrease in temperature and decrease in 2,3-DPG. The fetal haemoglobin curve is to the left of the adult haemoglobin to allow for oxygen diffusion across the placenta. The curve for myoglobin is even further to the left. Carbon monoxide has a much higher affinity for haemoglobin than oxygen does. Thus, carbon monoxide poisoning leads to hypoxia.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 4
Correct
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The nasolacrimal duct is a membranous canal. It extends from the lower part of the lacrimal sac and drains into which structure?
Your Answer: Inferior meatus
Explanation:The nasolacrimal duct carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. The opening of the nasolacrimal duct into the inferior nasal meatus of the nasal cavity is partially covered by a mucosal fold (valve of Hasner or plica lacrimalis). Excess tears flow through the nasolacrimal duct which drains into the inferior nasal meatus.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 5
Correct
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A 40 year old man suffered severe trauma following a MVA. His BP is 72/30 mmhg, heart rate of 142 beats/mins and very feeble pulse. He was transfused 3 units of blood and his BP returned to 100/70 and his heart rate slowed to 90 beats/min. What decreased after transfusion?
Your Answer: Total peripheral resistance
Explanation:The patient is in hypovolemic shock, he is transfused with blood, this fluid resuscitation will result in a decreased sympathetic discharge and adequate ventricular filling which will result in the decreases TPR with an increased CO and cardiac filling pressures
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 6
Incorrect
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A 5-year-old child diagnosed with nephrotic syndrome developed generalised oedema. What is the mechanism for the development of oedema in patients with nephrotic syndrome?
Your Answer: Increased capillary hydrostatic pressure
Correct Answer: Decreased colloid osmotic pressure
Explanation:The development of oedema in nephrotic syndrome has traditionally been viewed as an underfill mechanism. According to this view, urinary loss of protein results in hypoalbuminemia and decreased plasma oncotic pressure. As a result, plasma water translocates out of the intravascular space and results in a decrease in intravascular volume. In response to the underfilled circulation, effector mechanisms are then activated that signal the kidney to secondarily retain salt and water. While an underfill mechanism may be responsible for oedema formation in a minority of patients, recent clinical and experimental findings would suggest that oedema formation in most nephrotic patients is the result of primary salt retention. Direct measurements of blood and plasma volume or measurement of neurohumoral markers that indirectly reflect effective circulatory volume are mostly consistent with either euvolemia or a volume expanded state. The ability to maintain plasma volume in the setting of a decreased plasma oncotic pressure is achieved by alterations in transcapillary exchange mechanisms known to occur in the setting of hypoalbuminemia that limit excessive capillary fluid filtration.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 7
Incorrect
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A 55 year old man presented with a 4 day history of cough and fever. His sputum culture showed the presence of Strep pneumoniae. Which of the following substances produced by the inflammatory cells will result in effective clearance of this organism from the lung parenchyma?
Your Answer: Prostaglandins
Correct Answer: Hydrogen peroxide
Explanation:Hydrogen peroxide is produced by myeloperoxidase to form a potent oxidant that eliminates bacteria, but is not effective in chronic granulomatous diseases.
Platelet activating factor will lead to the activation, adhesion and aggregation of platelets but will not directly kill bacteria.
Prostaglandins cause vasodilation but do not activate neutrophils.
Kallikrein promotes formation of bradykinin that leads to vasodilation.
Leukreines increase vascular permeability.
Cytokines are communicating molecules between immune cells but directly will not kill bacteria.
Interleukins will regulate the immune response.
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This question is part of the following fields:
- Inflammation & Immunology; Respiratory
- Pathology
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Question 8
Incorrect
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A 50-year old, obese gentleman with a compression fracture of T11 vertebra was admitted in the hospital. Examination revealed a raised blood pressure 165/112 mmHg and blood glucose 8.5 mmol/l. His abdomen had the presence of purplish striae. What condition is he likely to be suffering from?
Your Answer: Pheochromocytoma
Correct Answer: Adrenal cortical carcinoma
Explanation:Adrenocortical carcinomas are rare tumours with reported incidence being only two in a million. However, they have a poor prognosis. These are large tumours and range from 4-10 cm in diameter. They arise from the adrenal cortex and 10% cases are bilateral. 50-80% are known to be functional, leading to Cushing syndrome. Even though the tumour affects both sexes equally, functional tumours are slightly commoner in women and non-functional tumours are commoner in men. As compared to women, men also develop this tumour at an older age and seem to have a poorer prognosis.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 9
Correct
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A surgeon performing a thymectomy to remove a malignant thymoma is careful to avoid damaging an important nerve lying around the arch of the aorta. Which nerve is the surgeon trying to preserve?
Your Answer: Left Vagus
Explanation:The left vagus nerve lies on the lateral surface of the aortic arch. The left recurrent laryngeal nerve arises from the vagus and loops around the arch of the aorta. This nerve is at risk of injury during surgery.
The right and left phrenic nerves, being lateral to the vagus, do not loop around the arch of the aorta.
The sympathetic trunks, both right and left, are located in the posterior chest; not near the aortic arch.
The right vagus: not involved with the aortic arch.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 10
Correct
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What is the primary function of the Kupffer cells found in the liver?
Your Answer: Recycling of old red blood cells
Explanation:Kupffer cells found in the liver are part of the monocyte-reticular system. They are specialised macrophages and primarily function to recycle old and damaged RBCs. The RBCs are phagocytosed and the haemoglobin is broken down into haem and globin. The haem is further broken down into iron that is recycled and bilirubin that is conjugated with glucuronic acid and excreted in the bile.
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This question is part of the following fields:
- Inflammation & Immunology; Hepatobiliary
- Pathology
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Question 11
Incorrect
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How are amino acids transported across the luminal surface of the small intestinal epithelium?
Your Answer: Primary active transport
Correct Answer: Co-transport with sodium ions
Explanation:Once complex peptides are broken down into amino acids by the peptidases present in the brush border of small intestine, they are ready for absorption by at least four sodium-dependent amino acid co-transporters – one each for acidic, basic, neutral and amino acids, present on the luminal plasma membrane. These transporters first bind sodium and can then bind the amino acids. Thus, amino acid absorption is totally dependent on the electrochemical gradient of sodium across the epithelium. The basolateral membrane in contrast, possesses additional transporters to carry amino acids from the cell into the blood, but these are sodium-independent.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 12
Correct
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The third branch of the maxillary artery lies in which fossa?
Your Answer: Pterygopalatine fossa
Explanation:The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. It is divided into three portions:
– The first or mandibular portion (or bony portion) passes horizontally forward, between the neck of the mandible and the sphenomandibular ligament.
– The second or pterygoid portion (or muscular portion) runs obliquely forward and upward under cover of the ramus of the mandible, on the surface of the lateral pterygoid muscle; it then passes between the two heads of origin of this muscle and enters the fossa.
– The third portion lies in the pterygopalatine fossa in relation to the pterygopalatine ganglion. This is considered the terminal branch of the maxillary artery. Branches from the third portion includes: the sphenopalatine artery, descending palatine artery, infraorbital artery, posterior superior alveolar artery, artery of pterygoid canal, pharyngeal artery, middle superior alveolar artery and anterior superior alveolar artery.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 13
Incorrect
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A 46-year old female patient experienced a stroke that affected her glossopharyngeal nerve. Damage to the glossopharyngeal nerve would most likely:
Your Answer: Affect the parasympathetic innervation to the submandibular gland
Correct Answer: Result in general sensory deficit to the pharynx
Explanation:The glossopharyngeal nerve (CN IX) has many functions which include:
– Contributes to the pharyngeal plexus
– Receiving general somatic sensory fibres from the tonsils, pharynx, the middle ear and the posterior third of the tongue.
– supplies motor fibres to only one muscle; the stylopharyngeus muscle.
– provides parasympathetic fibres to the parotid gland via the otic ganglion.
– Receives visceral sensory fibres from the carotid bodies & carotid sinus.
– Receives special visceral sensory fibres from the posterior third of the tongue.
The above functions will directly be affected by the damage of the glossopharyngeal nerve.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 14
Correct
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The Carpal tunnel does NOT contain:
Your Answer: Flexor carpi ulnaris
Explanation:The contents of the carpal tunnel include:
– Median nerve
– Flexor digitorum supervicialis
– Flexor digitorum profundus
– Flexor policis longus
– Flexor carpi radialis
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 15
Incorrect
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Which of the following conditions is likely to result in splenomegaly, hypochromic anaemia and hemochromatosis in a young male?
Your Answer: Sickle cell anaemia
Correct Answer: β-Thalassaemia
Explanation:Beta-thalassaemia is due to decreased production of β-polypeptide chains, with an autosomal inheritance pattern. Carrier patients (heterozygotes) are asymptomatic and have mild to moderate microcytic anaemia. This is known as thalassaemia minor. Homozygotes (β-thalassaemia major, or Cooley’s anaemia) develop severe anaemia and marrow hyperactivity. The disease presents at 1-2 years of age with severe anaemia and transfusional and absorptive iron overload. Patients also present with jaundice, leg ulcers, massive splenomegaly and cholelithiasis. The disease can also lead to splenic sequestration leading to faster destruction of transfused red blood cells. Increased marrow activity causes thickening of cranial bones. Involvement of long bones is also seen, which can cause pathological fractures and growth impairment. There is iron deposition in various organs, which can lead to heart failure or hepatic failure (leading to cirrhosis). Thalassaemias are suspected in presence of family history, or signs suggesting microcytic haemolytic anaemia. Further test and quantitative haemoglobin studies are useful. In beta-thalassaemia, there is an increase in serum bilirubin, iron and ferritin levels. There is severe anaemia, often with haemoglobin < 6 g/dl. There is an elevated red blood cell count, which are microcytic. Peripheral blood smear is diagnostic with nucleated erythroblasts, target cells, small pale red blood cells, and punctate basophilia.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 16
Incorrect
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Following a fracture in the fibula, an artery contained in a fibrous canal between tibialis posterior and flexor hallucis longus was lacerated. Which of the following arteries was injured?
Your Answer: Dorsalis pedis
Correct Answer: Peroneal
Explanation:The peroneal artery is deeply seated at the back of the fibular side of the leg, contained in a fibrous canal between the tibialis posterior and the flexor hallucis longus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 17
Correct
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A 25 year-old female medical student presents with fever, lack of appetite, rashes, sore throat and lymphadenopathy. Peripheral smear shows atypical lymphocytes. Which is the most likely organism responsible for this patient's condition?
Your Answer: Epstein–Barr virus
Explanation:Epstein-Barr virus is in the herpes family of viruses and most people will become infected with EBV sometime during their lives. EBV commonly causes infectious mononucleosis, or mono, a contagious viral illness that initially attacks the lymph nodes in the neck and throat. When these tissues become less effective in fighting infection, sore throats, swelling of the nodes and fever may result.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 18
Correct
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Which of the following is the most likely cause of massive splenomegaly in a 35-year old gentleman?
Your Answer: Myelofibrosis
Explanation:Causes of massive splenomegaly include chronic myelogenous leukaemia, chronic lymphocytic leukaemia, lymphoma, hairy cell leukaemia, myelofibrosis, polycythaemia vera, sarcoidosis, Gaucher’s disease and malaria.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 19
Incorrect
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During a surgical procedure involving the carotid artery, which nerve in the cervical plexus of nerves that is embedded in the carotid sheath is most susceptible to injury?
Your Answer: Transverse cervical nerve
Correct Answer: Ansa cervicalis
Explanation:The ansa cervicalis is a loop of nerves that are part of the cervical plexus. They lie superficial to the internal jugular vein in the carotid triangle. Branches from the ansa cervicalis innervate the sternohyoid, sternothyroid and the inferior belly of the omohyoid. The superior root of the ansa cervicalis is formed by a branch of spinal nerve C1. These nerve fibres travel in the hypoglossal nerve before leaving to form the superior root. The superior root goes around the occipital artery and then descends embedded in the carotid sheath. It sends a branch off to the superior belly of the omohyoid muscle and is then joined by the inferior root. The inferior root is formed by fibres from spinal nerves C2 and C3.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 20
Correct
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A tumour on the floor of the fourth ventricle is most likely to compress which of the following cranial nerve nuclei?
Your Answer: Abducent
Explanation:The fourth ventricle, is a cavity of the brains ventricular system in which the cerebrospinal fluid is formed. This cavity is located behind the pons and upper half of the medulla oblongata. It extends from the cerebral aqueduct, to its connection to the third ventricle, and to the obex- which is the caudal tip of the fourth ventricle. The floor of the fourth ventricle consists of three parts – superior, intermediate and inferior. This inferior aspect of the floor of the fourth ventricle has the nucleus of the abducens nerve, CN VI which is looped over by the facial nerve.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 21
Correct
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A 39-year old female patient was diagnosed with a tumour of the left adrenal gland. The tumour, which is metastasizing to the adjacent tissues, has already extended to the left suprarenal vein. If the tumour is still spreading, which of the following veins will most likely be affected after the involvement of the left suprarenal vein?
Your Answer: Left renal vein
Explanation:The suprarenal veins or also known as the veins of Warshaw, are the veins that receive blood from the suprarenal glands. These veins receive blood from the medullary venous plexus and the cortex of the adrenal glands (suprarenal glands). They are two in number – the left and the right suprarenal veins. The right suprarenal vein drains into the inferior vena cava while the left suprarenal vein drains into the left renal vein. This therefore means that in the case of a metastasizing tumour involving the left suprarenal vein, the tumour will most likely extend from the left suprarenal vein to the left renal vein into which it drains.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 22
Correct
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Severe abdominal pain radiating to the back, along with increased serum amylase levels, is seen in which of the following conditions?
Your Answer: Pancreatitis
Explanation:The primary test for diagnosis and monitoring of pancreatitis is amylase. Increased plasma levels of amylase can be found in: salivary trauma (including anaesthetic intubation), mumps, pancreatitis and renal failure. However, a rise in the total amylase levels over 10 times the upper limit of normal (ULN) is suggestive of pancreatitis; 5–10 times the ULN may indicate ileus or duodenal disease or renal failure. Lower levels are commonly found in salivary gland disease.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 23
Incorrect
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A 60-year-old woman has had persistent diarrhoea for a week. A stool test reveals an infection by Clostridium difficile. Which of the following antibiotics could be used to treat the infection?
Your Answer: Ciprofloxacin
Correct Answer: Oral vancomycin
Explanation:Three antibiotics are effective against Clostridium difficile:
Metronidazole 500 mg orally three times daily is the drug of choice, because of superior tolerability, lower price and comparable efficacy.
Oral vancomycin 125 mg four times daily is second-line therapy in particular cases of relapse or where the infection is unresponsive to metronidazole treatment.
Thirdly, the use of linezolid might also be considered.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 24
Correct
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During a case presentation, a 26 year old is said to have fractured his pelvis and shattered his coccyx following a motorbike accident. It is mentioned that he is likely to have lacerated his middle sacral artery from this kind of injury. Where does the middle sacral artery branch from?
Your Answer: Abdominal aorta
Explanation:The middle sacral artery arises from behind the aorta a little above the point of its bifurcation to descend down in front of L4,5, the sacrum and coccyx.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 25
Incorrect
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During work up for a 29 year-old lady who complained of chest pain, a computed tomography showed a large mass in the posterior mediastinum. Which among the following structures could be involved?
Your Answer: Aortic arch
Correct Answer: Lymph nodes
Explanation:Boundaries of the posterior mediastinum include:
Superior: a plane through the sternal angle and T4/5
Inferior: the diaphragm
Anterior: the middle mediastinal structures
Posterior the spinal cord.
Structures in the posterior mediastinum include the descending thoracic aorta, the azygos system, oesophagus, thoracic duct and lymph nodes. The great vessels and structures at the root of the lung are part of the middle mediastinum. In this case, the lymph nodes is the correct answer.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 26
Correct
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What forms the pelvic diaphragm?
Your Answer: Levator ani and coccygeus muscles
Explanation:The pelvic diaphragm is formed by the levator ani and the coccygeus muscles. The levator ani forms the greater part of the pelvic floor supporting the viscera in the pelvic cavity.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 27
Incorrect
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A 35 year-old woman is undergoing thyroidectomy. The external laryngeal nerve may be injured whilst ligating this artery during the procedure due to its close relationship?
Your Answer: Inferior laryngeal artery
Correct Answer: Superior thyroid artery
Explanation:The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland. This artery must be ligated at the thyroid when conducting a thyroidectomy. If the artery is severed, but not ligated, it will bleed profusely. In order to gain control of the bleeding, the surgeon may need to extend the original incision laterally to ligate the artery at its origin at the external carotid artery. The external laryngeal branch of the superior laryngeal nerve courses in close proximity to the superior thyroid artery, making it at risk for injury during surgery.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 28
Incorrect
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Which muscle originates from the common flexor tendon of the forearm?
Your Answer: Flexor pollicis longus
Correct Answer: Flexor digitorum superficialis
Explanation:The medial epicondyle of the humerus is the site of origin of this group of muscles of the forearm. It originates from the medial epicondyle of the humerus by a common tendon. Fibres from the deep fascia of the forearm, near the elbow and septa, pass from this fascia between the muscles. These muscles include the pronator teres, palmaris longus, flexor carpi radialis, flexor carpi ulnaris and flexor digitorum superficialis.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 29
Correct
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A sudden loud sound is more likely to result in cochlear damage than a slowly developing loud sound. This is because:
Your Answer: There is a latent period before the attenuation reflex can occur
Explanation:On transmission of a loud sound into the central nervous system, an attenuation reflex occurs after a latent period of 40-80 ms. This reflex contracts the two muscles that pull malleus and stapes closer, developing a high degree of rigidity in the entire ossicular chain. This reduces the ossicular conduction of low frequency sounds to the cochlea by 30-40 decibels. In this way, the cochlea is protected from damage due to loud sounds (these are low frequency sounds) when they develop slowly.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 30
Incorrect
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If a catheter is placed in the main pulmonary artery of a healthy 30-year-old woman, which of the following will be its mean pulmonary arterial pressure?
Your Answer: 10 mmHg
Correct Answer: 15 mmHg
Explanation:The pulmonary artery pressure (PA pressure) is a measure of the blood pressure found in the main pulmonary artery. The hydrostatic pressure of the pulmonary circulation refers to the actual pressure inside pulmonary vessels relative to atmospheric pressure. Hydrostatic (blood pressure) in the pulmonary vascular bed is low compared with that of similar systemic vessels. The mean pulmonary arterial pressure is about 15 mmHg (ranging from about 13 to 19 mmHg) and is much lower than the average systemic arterial pressure of 90 mmHg.
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
