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Question 1
Correct
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A 94-year-old male is admitted to the emergency department after being found on the floor for several hours due to a fall. What blood test is crucial to perform in a patient who has been immobile for an extended period of time?
Your Answer: Creatine kinase
Explanation:When an elderly person remains in bed for an extended period, the pressure on their muscles can cause muscle death and rhabdomyolysis. This leads to the breakdown of skeletal muscles and the release of muscle contents into the bloodstream, resulting in hyperkalemia. This is a medical emergency that can cause cardiac arrest.
Therefore, it is crucial to test for creatine kinase in patients who have been bedridden for a long time to diagnose rhabdomyolysis. Creatine kinase levels will be elevated and may reach several tens of thousands.
To investigate the cause of the fall, other blood tests may be necessary, such as calcium to check for dehydration, sodium to detect hyponatremia, and troponin to determine if there was a cardiac ischemic event.
Hyperkalaemia is a condition where there is an excess of potassium in the blood. The levels of potassium in the plasma are regulated by various factors such as aldosterone, insulin levels, and acid-base balance. When there is metabolic acidosis, hyperkalaemia can occur as hydrogen and potassium ions compete with each other for exchange with sodium ions across cell membranes and in the distal tubule. The ECG changes that can be seen in hyperkalaemia include tall-tented T waves, small P waves, widened QRS leading to a sinusoidal pattern, and asystole.
There are several causes of hyperkalaemia, including acute kidney injury, drugs such as potassium sparing diuretics, ACE inhibitors, angiotensin 2 receptor blockers, spironolactone, ciclosporin, and heparin, metabolic acidosis, Addison’s disease, rhabdomyolysis, and massive blood transfusion. Foods that are high in potassium include salt substitutes, bananas, oranges, kiwi fruit, avocado, spinach, and tomatoes.
It is important to note that beta-blockers can interfere with potassium transport into cells and potentially cause hyperkalaemia in renal failure patients. In contrast, beta-agonists such as Salbutamol are sometimes used as emergency treatment. Additionally, both unfractionated and low-molecular weight heparin can cause hyperkalaemia by inhibiting aldosterone secretion.
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This question is part of the following fields:
- Renal System
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Question 2
Incorrect
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Sophie is a 5-year-old girl who has presented with a complicated urinary tract infection. She has been treated with the most appropriate antibiotic for 72-hours now and there is no improvement.
What is the appropriate action to take regarding an ultrasound scan?Your Answer: He will need an ultrasound scan in the next 6 weeks, but not during the infection
Correct Answer: He will need an ultrasound scan during the course of the infection
Explanation:According to NICE guidelines, an ultrasound scan should be performed on all children who present with a UTI and abnormal features during the acute phase of the infection. This is particularly important in cases of complicated UTIs, where there is no improvement in symptoms after 72 hours of appropriate treatment. It is crucial to perform the ultrasound scan during the infection rather than waiting for six weeks, as there could be underlying issues that need to be addressed. It is important to note that the need for an ultrasound scan should not compromise the need for further urine sampling or a change in antibiotics. Additionally, an ultrasound scan is a non-invasive procedure that poses no direct risk of infection and will not exacerbate the UTI.
Urinary tract infections (UTIs) in children require investigation to identify any underlying causes and potential kidney damage. Unlike in adults, the development of a UTI in childhood may indicate renal scarring. The National Institute for Health and Care Excellence (NICE) recommends imaging the urinary tract for infants under six months who present with their first UTI and respond to treatment, within six weeks. Children over six months who respond to treatment do not require imaging unless there are features suggestive of an atypical infection, such as being seriously ill, having poor urine flow, an abdominal or bladder mass, raised creatinine, septicaemia, failure to respond to antibiotics within 48 hours, or infection with non-E. coli organisms.
Further investigations may include a urine microscopy and culture, as only 50% of children with a UTI have pyuria, making microscopy or dipstick of the urine inadequate for diagnosis. A static radioisotope scan, such as DMSA, can identify renal scars and should be done 4-6 months after the initial infection. Micturating cystourethrography (MCUG) can identify vesicoureteral reflux and is only recommended for infants under six months who present with atypical or recurrent infections.
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This question is part of the following fields:
- General Principles
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Question 3
Correct
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A 10-year-old girl with no previous medical history presents to the emergency department with vomiting and diarrhea. She also complains of abdominal pain. A venous blood gas test is performed and shows the following results:
Normal range
pH: 7.14 (7.35 - 7.45)
pO2: 11.6 (10 - 14)kPa
pCO2: 3.3 (4.5 - 6.0)kPa
HCO3: 10 (22 - 26)mmol/l
BE: -16 (-2 to +2)mmol/l
Lactate: 4.1 0.6-1.8mmol/l
Potassium: 5.4 3.5-5 mmol/l
A blood glucose finger-prick test is also performed, which reads Glucose = 24. Based on the information provided, what is the most likely diagnosis?Your Answer: Diabetic ketoacidosis
Explanation:Diabetic ketoacidosis is depicted in this image. It is a critical condition that requires urgent attention, with a focus on administering insulin, fluid resuscitation, and closely monitoring potassium levels.
Diabetic ketoacidosis (DKA) is a serious complication of type 1 diabetes mellitus, accounting for around 6% of cases. It can also occur in rare cases of extreme stress in patients with type 2 diabetes mellitus. DKA is caused by uncontrolled lipolysis, resulting in an excess of free fatty acids that are converted to ketone bodies. The most common precipitating factors of DKA are infection, missed insulin doses, and myocardial infarction. Symptoms include abdominal pain, polyuria, polydipsia, dehydration, Kussmaul respiration, and breath that smells like acetone. Diagnostic criteria include glucose levels above 11 mmol/l or known diabetes mellitus, pH below 7.3, bicarbonate below 15 mmol/l, and ketones above 3 mmol/l or urine ketones ++ on dipstick.
Management of DKA involves fluid replacement, insulin, and correction of electrolyte disturbance. Fluid replacement is necessary as most patients with DKA are deplete around 5-8 litres. Isotonic saline is used initially, even if the patient is severely acidotic. Insulin is administered through an intravenous infusion, and correction of electrolyte disturbance is necessary. Long-acting insulin should be continued, while short-acting insulin should be stopped. Complications may occur from DKA itself or the treatment, such as gastric stasis, thromboembolism, arrhythmias, acute respiratory distress syndrome, acute kidney injury, and cerebral edema. Children and young adults are particularly vulnerable to cerebral edema following fluid resuscitation in DKA and often need 1:1 nursing to monitor neuro-observations, headache, irritability, visual disturbance, focal neurology, etc.
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This question is part of the following fields:
- Endocrine System
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Question 4
Correct
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A 25-year-old female has received a pan proctocolectomy and ileoanal pouch due to familial adenomatous polyposis coli. What is the most frequent non-colonic manifestation of this condition?
Your Answer: Duodenal polyps
Explanation:Polyposis syndromes are a group of genetic disorders that cause the development of multiple polyps in the colon and other parts of the gastrointestinal tract. These polyps can increase the risk of developing cancer, and therefore, early detection and management are crucial. There are several types of polyposis syndromes, each with its own genetic defect, features, and associated disorders.
Familial adenomatous polyposis (FAP) is caused by a mutation in the APC gene and is characterized by the development of over 100 colonic adenomas, with a 100% risk of cancer. Screening and management involve regular colonoscopies and resectional surgery if polyps are found. FAP is also associated with gastric and duodenal polyps and abdominal desmoid tumors.
MYH-associated polyposis is caused by a biallelic mutation of the MYH gene and is associated with multiple colonic polyps and an increased risk of right-sided cancers. Attenuated phenotype can be managed with regular colonoscopies, while resection and ileoanal pouch reconstruction are recommended for those with multiple polyps.
Peutz-Jeghers syndrome is caused by a mutation in the STK11 gene and is characterized by multiple benign intestinal hamartomas, episodic obstruction, and an increased risk of GI cancers. Screening involves annual examinations and pan-intestinal endoscopy every 2-3 years.
Cowden disease is caused by a mutation in the PTEN gene and is characterized by macrocephaly, multiple intestinal hamartomas, and an increased risk of cancer at any site. Targeted individualized screening is recommended, with extra surveillance for breast, thyroid, and uterine cancers.
HNPCC (Lynch syndrome) is caused by germline mutations of DNA mismatch repair genes and is associated with an increased risk of colorectal, endometrial, and gastric cancers. Colonoscopies every 1-2 years from age 25 and consideration of prophylactic surgery are recommended, along with extra colonic surveillance.
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This question is part of the following fields:
- Gastrointestinal System
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Question 5
Correct
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An 80-year-old man with symptoms of intermittent claudication needs to have his ankle brachial pressure indices checked. However, the dorsalis pedis artery cannot be felt. What tendinous structure, located medially, could aid in its identification?
Your Answer: Extensor hallucis longus tendon
Explanation:The dorsalis pedis artery is located lateral to the extensor hallucis longus tendon.
The foot has two arches: the longitudinal arch and the transverse arch. The longitudinal arch is higher on the medial side and is supported by the posterior pillar of the calcaneum and the anterior pillar composed of the navicular bone, three cuneiforms, and the medial three metatarsal bones. The transverse arch is located on the anterior part of the tarsus and the posterior part of the metatarsus. The foot has several intertarsal joints, including the sub talar joint, talocalcaneonavicular joint, calcaneocuboid joint, transverse tarsal joint, cuneonavicular joint, intercuneiform joints, and cuneocuboid joint. The foot also has various ligaments, including those of the ankle joint and foot. The foot is innervated by the lateral plantar nerve and medial plantar nerve, and it receives blood supply from the plantar arteries and dorsalis pedis artery. The foot has several muscles, including the abductor hallucis, flexor digitorum brevis, abductor digit minimi, flexor hallucis brevis, adductor hallucis, and extensor digitorum brevis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 6
Incorrect
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A 45-year-old female patient presents to her GP with increasing muscular fatigue, mainly affecting the muscles of face. The fatigue is worse in the evenings or when using the muscle for prolonged periods. She also complains of diplopia and difficulty swallowing. On examination, she has a bilateral, partial ptosis. Tendon reflexes are normal. Her past medical history includes hypothyroidism and pernicious anaemia.
In which area of the mediastinum is the structure likely to have undergone hyperplasia in this patient?Your Answer: Posterior superior mediastinum
Correct Answer: Anterior superior mediastinum
Explanation:The Thymus Gland: Development, Structure, and Function
The thymus gland is an encapsulated organ that develops from the third and fourth pharyngeal pouches. It descends to the anterior superior mediastinum and is subdivided into lobules, each consisting of a cortex and a medulla. The cortex is made up of tightly packed lymphocytes, while the medulla is mostly composed of epithelial cells. Hassall’s corpuscles, which are concentrically arranged medullary epithelial cells that may surround a keratinized center, are also present.
The inferior parathyroid glands, which also develop from the third pharyngeal pouch, may be located with the thymus gland. The thymus gland’s arterial supply comes from the internal mammary artery or pericardiophrenic arteries, while its venous drainage is to the left brachiocephalic vein. The thymus gland plays a crucial role in the development and maturation of T-cells, which are essential for the immune system’s proper functioning.
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This question is part of the following fields:
- Haematology And Oncology
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Question 7
Incorrect
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At what age does the Moro reflex usually disappear?
Your Answer: 2-3 months
Correct Answer: 4-6 months
Explanation:The Moro reflex vanishes by the time the baby reaches 4 months of age.
Primitive Reflexes in Infants
Primitive reflexes are automatic movements that are present in infants from birth to a certain age. These reflexes are important for survival and development in the early stages of life. One of the most well-known primitive reflexes is the Moro reflex, which is triggered by head extension and causes the arms to first spread out and then come back together. This reflex is present from birth to around 3-4 months of age.
Another primitive reflex is the grasp reflex, which causes the fingers to flex when an object is placed in the infant’s palm. This reflex is present from birth to around 4-5 months of age and is important for the infant’s ability to grasp and hold objects.
The rooting reflex is another important primitive reflex that assists in breastfeeding. When the infant’s cheek is touched, they will turn their head towards the touch and open their mouth to suck. This reflex is present from birth to around 4 months of age.
Finally, the stepping reflex, also known as the walking reflex, is present from birth to around 2 months of age. When the infant’s feet touch a flat surface, they will make stepping movements as if they are walking. This reflex is important for the development of the infant’s leg muscles and coordination.
Overall, primitive reflexes are an important part of infant development and can provide insight into the health and functioning of the nervous system.
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This question is part of the following fields:
- Neurological System
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Question 8
Incorrect
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A 36-year-old male visits the GP after being diagnosed with Conn's syndrome, which causes excessive production of aldosterone. How will this affect the balance of sodium and potassium in his blood?
Your Answer: Decreased sodium, increased potassium
Correct Answer: Increased sodium, decreased potassium
Explanation:Hypertension, hypernatraemia, and hypokalemia are common symptoms of primary hyperaldosteronism.
The adrenal gland produces aldosterone, which is responsible for regulating potassium levels. Its primary function is to increase sodium absorption and decrease potassium secretion in the distal tubules and collecting duct of the nephron. As a result, sodium levels increase while potassium levels decrease.
Primary hyperaldosteronism is a condition characterized by hypertension, hypokalaemia, and alkalosis. It was previously believed that adrenal adenoma, also known as Conn’s syndrome, was the most common cause of this condition. However, recent studies have shown that bilateral idiopathic adrenal hyperplasia is responsible for up to 70% of cases. It is important to differentiate between the two causes as it determines the appropriate treatment. Adrenal carcinoma is an extremely rare cause of primary hyperaldosteronism.
To diagnose primary hyperaldosteronism, the 2016 Endocrine Society recommends a plasma aldosterone/renin ratio as the first-line investigation. This test should show high aldosterone levels alongside low renin levels due to negative feedback from sodium retention caused by aldosterone. If the results are positive, a high-resolution CT abdomen and adrenal vein sampling are used to differentiate between unilateral and bilateral sources of aldosterone excess. If the CT is normal, adrenal venous sampling (AVS) can be used to distinguish between unilateral adenoma and bilateral hyperplasia.
The management of primary hyperaldosteronism depends on the underlying cause. Adrenal adenoma is treated with surgery, while bilateral adrenocortical hyperplasia is managed with an aldosterone antagonist such as spironolactone. It is important to accurately diagnose and manage primary hyperaldosteronism to prevent complications such as cardiovascular disease and stroke.
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This question is part of the following fields:
- Endocrine System
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Question 9
Incorrect
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A 78-year-old man is diagnosed with a vitamin B1 deficiency. What food is known to be a rich source of thiamine?
Your Answer: Broccoli
Correct Answer: Wheat germ
Explanation:Thiamine Deficiency and Dietary Sources
Thiamine, also known as vitamin B1, is an essential nutrient that the body cannot store in large amounts and must be obtained through the diet. Wholegrain cereals, oatmeal, yeast, pork, sunflower seeds, and certain vegetables such as potatoes, asparagus, and cauliflower are good dietary sources of thiamine. However, refined cereals and white flour typically contain low levels of thiamine, and processing, boiling, and overcooking vegetables can remove a significant amount of the vitamin.
Thiamine plays a crucial role in energy production, nervous transmission, and collagen synthesis. A deficiency in thiamine can lead to impairment of these processes, resulting in various signs and symptoms such as muscle tenderness, weakness, and reduced reflexes, confusion, memory impairment, impaired wound healing, poor balance, falls, constipation, and reduced appetite. Therefore, it is important to ensure adequate intake of thiamine through a balanced diet to prevent deficiency and maintain optimal health.
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This question is part of the following fields:
- Clinical Sciences
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Question 10
Incorrect
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Which statistical measure would be most helpful in order to reassure a 60-year-old patient who has received a negative test result?
Your Answer: Sensitivity
Correct Answer: Negative predictive value
Explanation:Precision refers to the consistency of a test in producing the same results when repeated multiple times. It is an important aspect of test reliability and can impact the accuracy of the results. In order to assess precision, multiple tests are performed on the same sample and the results are compared. A test with high precision will produce similar results each time it is performed, while a test with low precision will produce inconsistent results. It is important to consider precision when interpreting test results and making clinical decisions.
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This question is part of the following fields:
- General Principles
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Question 11
Incorrect
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A 75-year-old man is brought to the Emergency Department after he was found on the floor at home following a fall. He reports being immobile and staying on the floor overnight, but was otherwise healthy with no chest pain or dizziness. He is slightly confused and dehydrated, and complains of hip pain. However, further investigation reveals no fracture, but elevated levels of creatine kinase, creatinine, and urea. He takes simvastatin and amlodipine for hypercholesterolaemia and hypertension.
What is the most probable cause of this sudden kidney injury?Your Answer: Statin-induced myopathy
Correct Answer: Acute tubular necrosis
Explanation:The most common cause of acute kidney injury is acute tubular necrosis, which may be caused by various factors. In this case, the patient is likely to have rhabdomyolysis due to muscle damage from a fall. The release of myoglobin from damaged muscles can cause renal ischaemia, leading to acute tubular necrosis. Treatment involves addressing the cause of renal ischaemia and administering intravenous fluids to manage dehydration.
While statins can cause rhabdomyolysis, the patient’s history suggests direct muscle trauma as the cause. Malignancy is a possibility, but the absence of prior symptoms and sudden onset of symptoms after a fall make it less likely than muscle trauma.
IgA nephropathy typically presents with haematuria following an upper respiratory tract infection, but this is not relevant to the current case.
Acute tubular necrosis (ATN) is a common cause of acute kidney injury (AKI) that affects the functioning of the kidney by causing necrosis of renal tubular epithelial cells. The condition is reversible in its early stages if the cause is removed. The two main causes of ATN are ischaemia and nephrotoxins, which can be caused by shock, sepsis, aminoglycosides, myoglobin secondary to rhabdomyolysis, radiocontrast agents, and lead. The features of ATN include raised urea, creatinine, and potassium levels, as well as muddy brown casts in the urine. Histopathological features include tubular epithelium necrosis, dilatation of the tubules, and necrotic cells obstructing the tubule lumen. ATN has three phases: the oliguric phase, the polyuric phase, and the recovery phase.
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This question is part of the following fields:
- Renal System
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Question 12
Incorrect
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A 28-year-old man with schizophrenia who began taking clozapine 2 weeks ago visits for his routine blood test. What is a known severe side effect of clozapine?
Your Answer: Aplastic crisis
Correct Answer: Agranulocytosis
Explanation:Clozapine, an antipsychotic medication used to treat refractory schizophrenia, requires continuous monitoring for patients taking it. This involves weekly blood tests for the first 18 weeks, followed by bi-weekly tests until the first year, and then monthly tests thereafter.
Atypical antipsychotics are now recommended as the first-line treatment for patients with schizophrenia, as per the 2005 NICE guidelines. These agents have a significant advantage over traditional antipsychotics in that they cause fewer extrapyramidal side-effects. However, atypical antipsychotics can still cause adverse effects such as weight gain, hyperprolactinaemia, and clozapine-associated agranulocytosis. Elderly patients who take antipsychotics are at an increased risk of stroke and venous thromboembolism, according to the Medicines and Healthcare products Regulatory Agency.
Clozapine is one of the first atypical antipsychotics to be developed, but it carries a significant risk of agranulocytosis. Therefore, full blood count monitoring is essential during treatment. Clozapine should only be used in patients who are resistant to other antipsychotic medication. The BNF recommends introducing clozapine if schizophrenia is not controlled despite the sequential use of two or more antipsychotic drugs, one of which should be a second-generation antipsychotic drug, each for at least 6-8 weeks. Clozapine can cause adverse effects such as reduced seizure threshold, constipation, myocarditis, and hypersalivation. Dose adjustment of clozapine may be necessary if smoking is started or stopped during treatment.
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This question is part of the following fields:
- Psychiatry
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Question 13
Correct
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A 65-year-old man presents to the Emergency Department with confusion, drowsiness, and nausea accompanied by vomiting. His daughter reports that he has been feeling fatigued and unwell with a persistent cough, and he has been smoking 20 cigarettes per day for 45 years. The patient is unable to provide a complete medical history due to his confusion, but he mentions that he sometimes coughs up blood and his urine has been darker than usual. On examination, he appears to be short of breath but euvolaemic. Blood tests reveal low serum sodium, high urinary sodium, low plasma osmolality, and high urinary osmolality. Renal and thyroid function tests are normal. A chest x-ray shows a lung carcinoma, leading you to suspect that this presentation may be caused by a syndrome of inappropriate antidiuretic hormone secretion.
What is the underlying mechanism responsible for the hyponatraemia?Your Answer: Insertion of aquaporin-2 channels
Explanation:The insertion of aquaporin-2 channels is promoted by antidiuretic hormone, which facilitates water reabsorption. However, in the case of syndrome of inappropriate antidiuretic hormone secretion (SiADH), which is caused by small cell lung cancer, the normal negative feedback loop fails, resulting in the continuous production of ADH even when serum osmolality returns to normal. This leads to euvolemic hyponatremia, where the body retains water but continues to lose sodium, resulting in concentrated urine. The underlying mechanism of this condition is the persistent increase in the number of aquaporin-2 channels, which promotes water reabsorption, rather than any effect on sodium transport mechanisms.
Understanding Antidiuretic Hormone (ADH)
Antidiuretic hormone (ADH) is a hormone that is produced in the supraoptic nuclei of the hypothalamus and released by the posterior pituitary gland. Its primary function is to conserve body water by promoting water reabsorption in the collecting ducts of the kidneys through the insertion of aquaporin-2 channels.
ADH secretion is regulated by various factors. An increase in extracellular fluid osmolality, a decrease in volume or pressure, and the presence of angiotensin II can all increase ADH secretion. Conversely, a decrease in extracellular fluid osmolality, an increase in volume, a decrease in temperature, or the absence of ADH can decrease its secretion.
Diabetes insipidus (DI) is a condition that occurs when there is either a deficiency of ADH (cranial DI) or an insensitivity to ADH (nephrogenic DI). Cranial DI can be treated with desmopressin, which is an analog of ADH.
Overall, understanding the role of ADH in regulating water balance in the body is crucial for maintaining proper hydration and preventing conditions like DI.
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This question is part of the following fields:
- Endocrine System
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Question 14
Correct
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A 72-year-old male patient with heart failure experiences significant physical activity limitations. He is prescribed a medication that targets the collecting duct of the kidney, but is cautioned about potential breast tissue enlargement. What electrolyte imbalance could result from this medication?
Your Answer: Hyperkalaemia
Explanation:Hyperkalaemia may be caused by Spironolactone
Spironolactone is recognized for its potential to cause breast tissue growth as a side effect. As an aldosterone receptor antagonist, it hinders the elimination of potassium, making it a potassium-sparing diuretic.
Spironolactone is a medication that works as an aldosterone antagonist in the cortical collecting duct. It is used to treat various conditions such as ascites, hypertension, heart failure, nephrotic syndrome, and Conn’s syndrome. In patients with cirrhosis, spironolactone is often prescribed in relatively large doses of 100 or 200 mg to counteract secondary hyperaldosteronism. It is also used as a NICE ‘step 4’ treatment for hypertension. In addition, spironolactone has been shown to reduce all-cause mortality in patients with NYHA III + IV heart failure who are already taking an ACE inhibitor, according to the RALES study.
However, spironolactone can cause adverse effects such as hyperkalaemia and gynaecomastia, although the latter is less common with eplerenone. It is important to monitor potassium levels in patients taking spironolactone to prevent hyperkalaemia, which can lead to serious complications such as cardiac arrhythmias. Overall, spironolactone is a useful medication for treating various conditions, but its potential adverse effects should be carefully considered and monitored.
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This question is part of the following fields:
- Renal System
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Question 15
Correct
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A 65-year-old male arrives at the emergency department with alterations in his vision. During the conversation, he uses nonsensical words such as 'I went for a walk this morning and saw the tree lights shining'. However, he can communicate fluently. The possibility of a brain lesion is high.
Which specific region of the brain is likely to be impacted?Your Answer: Temporal lobe
Explanation:Fluent speech may still be present despite neologisms and word substitution resulting from temporal lobe lesions. Superior homonymous quadrantanopia may also occur. Apraxia can be caused by lesions in the parietal lobe, while changes to vision may result from lesions in the occipital lobe. Non-fluent speech can be caused by lesions in the frontal lobe, while ataxia, intention tremor, and dysdiadochokinesia may result from lesions in the cerebellum.
Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.
In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.
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This question is part of the following fields:
- Neurological System
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Question 16
Correct
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Which of the following muscles is not involved in shoulder adduction?
Your Answer: Supraspinatus
Explanation:The shoulder abductor is the supraspinatus.
The shoulder joint is a shallow synovial ball and socket joint that is inherently unstable but capable of a wide range of movement. Stability is provided by the muscles of the rotator cuff. The glenoid labrum is a fibrocartilaginous rim attached to the free edge of the glenoid cavity. The fibrous capsule attaches to the scapula, humerus, and tendons of various muscles. Movements of the shoulder joint are controlled by different muscles. The joint is closely related to important anatomical structures such as the brachial plexus, axillary artery and vein, and various nerves and vessels.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 17
Correct
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Where exactly can the vomiting center be found?
Your Answer: Medulla oblongata
Explanation:Here are the non-GI causes of vomiting, listed alphabetically:
– Acute renal failure
– Brain conditions that increase intracranial pressure
– Cardiac events, particularly inferior myocardial infarction
– Diabetic ketoacidosis
– Ear infections that affect the inner ear (labyrinthitis)
– Ingestion of foreign substances, such as Tylenol or theophylline
– Glaucoma
– Hyperemesis gravidarum, a severe form of morning sickness in pregnancy
– Infections such as pyelonephritis (kidney infection) or meningitis.Vomiting is the involuntary act of expelling the contents of the stomach and sometimes the intestines. This is caused by a reverse peristalsis and abdominal contraction. The vomiting center is located in the medulla oblongata and is activated by receptors in various parts of the body. These include the labyrinthine receptors in the ear, which can cause motion sickness, the over distention receptors in the duodenum and stomach, the trigger zone in the central nervous system, which can be affected by drugs such as opiates, and the touch receptors in the throat. Overall, vomiting is a reflex action that is triggered by various stimuli and is controlled by the vomiting center in the brainstem.
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This question is part of the following fields:
- Neurological System
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Question 18
Correct
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A 35-year-old male who has recently traveled to Nigeria visits the GP complaining of muscle weakness. During the clinical examination, the doctor observes reduced tone in his limbs, diminished reflexes, and fasciculations.
What is the probable diagnosis?Your Answer: Poliomyelitis
Explanation:Lower motor neuron signs are a common result of poliomyelitis, which is a viral infection that can cause reduced reflexes and tone. On the other hand, upper motor neuron signs are typically associated with conditions such as multiple sclerosis, stroke, and Huntington’s disease.
Understanding Poliomyelitis and Its Immunisation
Poliomyelitis is a sudden illness that occurs when one of the polio viruses invades the gastrointestinal tract. The virus then multiplies in the gastrointestinal tissues and targets the nervous system, particularly the anterior horn cells. This can lead to paralysis, which is usually unilateral and accompanied by lower motor neuron signs.
To prevent the spread of polio, immunisation is crucial. In the UK, the live attenuated oral polio vaccine (OPV – Sabin) was used for routine immunisation until 2004. However, this vaccine carried a risk of vaccine-associated paralytic polio. As the risk of polio importation to the UK has decreased, the country switched to inactivated polio vaccine (IPV – Salk) in 2004. This vaccine is administered via an intramuscular injection and does not carry the same risk of vaccine-associated paralytic polio as the OPV.
Certain factors can increase the risk of severe paralysis from polio, including being an adult, being pregnant, or having undergone a tonsillectomy. It is important to understand the features and risks associated with poliomyelitis to ensure proper prevention and treatment.
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This question is part of the following fields:
- Neurological System
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Question 19
Correct
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A 70-year-old man comes to the Parkinson clinic for a levodopa review. In Parkinson's disease, which region of the basal ganglia is most affected?
Your Answer: Substantia nigra pars compacta
Explanation:Parkinson’s disease primarily affects the basal ganglia, which is responsible for movement. Within the basal ganglia, the substantia nigra is a crucial component that plays a significant role in movement and reward. The dopaminergic neurons in the substantia nigra, which contain high levels of neuromelanin, function through the indirect pathway to facilitate movement. However, these neurons are the ones most impacted by Parkinson’s disease. The substantia nigra gets its name from its dark appearance, which is due to the abundance of neuromelanin in its neurons.
Parkinson’s disease is a progressive neurodegenerative disorder that occurs due to the degeneration of dopaminergic neurons in the substantia nigra. This leads to a classic triad of symptoms, including bradykinesia, tremor, and rigidity, which are typically asymmetrical. The disease is more common in men and is usually diagnosed around the age of 65. Bradykinesia is characterized by a poverty of movement, shuffling steps, and difficulty initiating movement. Tremors are most noticeable at rest and typically occur in the thumb and index finger. Rigidity can be either lead pipe or cogwheel, and other features include mask-like facies, flexed posture, and drooling of saliva. Psychiatric features such as depression, dementia, and sleep disturbances may also occur. Diagnosis is usually clinical, but if there is difficulty differentiating between essential tremor and Parkinson’s disease, 123I‑FP‑CIT single photon emission computed tomography (SPECT) may be considered.
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This question is part of the following fields:
- Neurological System
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Question 20
Correct
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A 24-year-old man with asthma is brought to the emergency department due to shortness of breath. He has been experiencing a worsening cough with thick yellow phlegm for the past three days. He regularly uses a beclomethasone inhaler and salbutamol inhaler as needed.
Upon assessment, the patient's heart rate is 166 bpm, blood pressure is 113/65 mmHg, oxygen saturation is 91%, and respiratory rate is 29. He is only able to speak in broken sentences.
Which of the following therapies is most likely to exacerbate his asthma?Your Answer: Bisoprolol
Explanation:Treatment for Acute Asthma Attack
When a person experiences an acute asthma attack, the first and most important treatment is to administer oxygen. This is followed by nebulised salbutamol to dilate the airways, oral steroids, and appropriate antibiotics if the productive cough is due to a chest infection. However, the use of the beta blocker bisoprolol to reduce the heart rate would be inappropriate.
Salbutamol works by targeting beta-2 adrenoceptors, which causes the bronchi to dilate. However, cardiac muscle also has beta adrenoceptors, which can cause an increased heart rate. In this case, the patient is likely tachycardic due to increased work of breathing and salbutamol administered on the way to the hospital. Bisoprolol, on the other hand, is a beta antagonist that counteracts these effects by causing a reduction in heart rate and smooth muscle constriction, which would constrict the bronchi. This is the opposite of the desired effect and can worsen the patient’s condition. Therefore, it is important to avoid using bisoprolol in the treatment of acute asthma attacks.
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This question is part of the following fields:
- Pharmacology
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Question 21
Correct
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After complaining of increasing irritability, difficulty concentrating and pain and weakness in his limbs, a 45-year-old patient with a history of alcoholism is sent for blood tests. The results reveal a vitamin deficiency and the general practitioner explains he has a condition called beriberi. Which vitamin is this patient deficient in?
Your Answer: Thiamine (vitamin B1)
Explanation:The Importance of Vitamin B1 (Thiamine) in the Body
Vitamin B1, also known as thiamine, is a water-soluble vitamin that belongs to the B complex group. It plays a crucial role in the body as one of its phosphate derivatives, thiamine pyrophosphate (TPP), acts as a coenzyme in various enzymatic reactions. These reactions include the catabolism of sugars and amino acids, such as pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and branched-chain amino acid dehydrogenase complex.
Thiamine deficiency can lead to clinical consequences, particularly in highly aerobic tissues like the brain and heart. The brain can develop Wernicke-Korsakoff syndrome, which presents symptoms such as nystagmus, ophthalmoplegia, and ataxia. Meanwhile, the heart can develop wet beriberi, which causes dilated cardiomyopathy. Other conditions associated with thiamine deficiency include dry beriberi, which leads to peripheral neuropathy, and Korsakoff’s syndrome, which causes amnesia and confabulation.
The primary causes of thiamine deficiency are alcohol excess and malnutrition. Alcoholics are routinely recommended to take thiamine supplements to prevent deficiency. Overall, thiamine is an essential vitamin that plays a vital role in the body’s metabolic processes.
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This question is part of the following fields:
- General Principles
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Question 22
Correct
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The following result is obtained on a 48-year-old male who is admitted with acute onset chest pain:
Serum Cholesterol 7.3 mmol/L (<5.2)
He has a strong family history of ischaemic heart disease.
What abnormalities might be expected upon examination of this man?Your Answer: Tendon nodules
Explanation:Familial Hypercholesterolaemia and its Manifestations
Familial hypercholesterolaemia is a condition characterized by high levels of cholesterol in the blood. This condition is often indicated by the deposition of cholesterol in various parts of the body. The history of the patient suggests that they may be suffering from familial hypercholesterolaemia. The deposition of cholesterol can be observed around the corneal arcus, around the eye itself (xanthelasma), and in tendons such as achilles, knuckles or triceps tendons (tendon xanthomas).
While dietary and lifestyle modifications are recommended, they are usually not enough to manage the condition. High dose lifelong statin therapy is often necessary to control the levels of cholesterol in the blood. It is important to seek medical attention and follow the recommended treatment plan to prevent further complications associated with familial hypercholesterolaemia. The National Institute for Health and Care Excellence (NICE) recommends the use of statin therapy in conjunction with lifestyle modifications for the management of familial hypercholesterolaemia.
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This question is part of the following fields:
- Pharmacology
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Question 23
Incorrect
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A 32-year-old female patient complains of a 12-hour duration of high fever, fatigue, and a widespread erythematous rash. She recently started her menstrual cycle 5 days ago and suspects that she may have unintentionally left a tampon inside for the past 4 days.
What organism is the most probable cause of her symptoms?Your Answer: Trichomonas vaginalis
Correct Answer: Staphylococcus aureus
Explanation:Staphylococcal toxic shock syndrome is primarily caused by the superantigen toxin TSST-1 produced by Staphylococcus aureus. This patient’s symptoms, including fever, fatigue, and rash after prolonged tampon use, are consistent with this diagnosis. Other symptoms may include flu-like symptoms, diarrhoea, dizziness, and confusion. Treatment involves hospital admission, antibiotics, and fluids. Escherichia coli, Gardnerella vaginalis, and Streptococcus pyogenes are not the primary cause of this syndrome.
Understanding Staphylococcal Toxic Shock Syndrome
Staphylococcal toxic shock syndrome is a severe reaction to staphylococcal exotoxins, specifically the TSST-1 superantigen toxin. It gained attention in the 1980s due to cases related to infected tampons. The Centers for Disease Control and Prevention have established diagnostic criteria for this syndrome, which includes fever, hypotension, a diffuse erythematous rash, desquamation of the rash (especially on the palms and soles), and involvement of three or more organ systems. These organ systems may include the gastrointestinal system, mucous membranes, kidneys, liver, blood platelets, and the central nervous system.
The management of staphylococcal toxic shock syndrome involves removing the source of infection, such as a retained tampon, and administering intravenous fluids and antibiotics. It is important to seek medical attention immediately if any of the symptoms of this syndrome are present.
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This question is part of the following fields:
- General Principles
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Question 24
Correct
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You are managing a pediatric patient with a multidrug resistant chest infection in the pediatric intensive care unit and are consulting with the pediatric infectious disease specialist regarding the antibiotics that have been administered. All of the following antibiotics inhibit protein synthesis in the bacterial ribosome except for which one?
Your Answer: Cefuroxime
Explanation:Mechanisms of Action of Antibiotics
Antibiotics are drugs that are used to treat bacterial infections. They work by targeting specific components of the bacterial cell, which can either kill the bacteria or stop them from multiplying. Cefuroxime is a second generation cephalosporin that inhibits cell wall synthesis, making it bactericidal. Chloramphenicol and clindamycin, on the other hand, bind to the 50S subunit of the bacterial ribosome, which prevents protein synthesis and is bacteriostatic. Aminoglycosides like gentamicin and tetracyclines such as doxycycline act on the 30S subunit, which disrupts protein synthesis and is bactericidal. the mechanisms of action of antibiotics is important in selecting the appropriate drug for a specific bacterial infection.
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This question is part of the following fields:
- Pharmacology
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Question 25
Incorrect
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A 50-year-old woman is suspected to have hepatitis B. She presents with jaundice and upper abdominal pain. A liver function test was conducted to assess her liver's synthetic capacity.
Which characteristic will provide the most precise indication of her condition?Your Answer: Liver function tests
Correct Answer: Prothrombin time
Explanation:Liver enzymes are not reliable indicators of liver function, especially in end-stage cirrhosis. Instead, coagulation and albumin levels are better measures to assess liver function.
Prothrombin time is a useful indicator because it reflects the liver’s ability to produce the necessary coagulation factors for blood clotting. A high PT suggests that the liver is not functioning properly.
C-reactive protein (CRP) is not a specific indicator of liver function as it can be elevated in response to any infection in the body.
Hemoglobin levels are not a reliable indicator of liver function as they can be affected by other factors such as anemia or polycythemia.
Liver function tests are not accurate in assessing synthetic liver function as they only reflect damage to the liver and its surrounding areas. Additionally, some LFTs can be elevated due to other conditions, not just liver disease. For example, elevated GGT levels in an LFT can indicate damage to the bile ducts, which can be caused by a gallstone blocking the duct.
Understanding Acute Liver Failure
Acute liver failure is a condition characterized by the sudden onset of liver dysfunction, which can lead to various complications in the body. The causes of acute liver failure include paracetamol overdose, alcohol, viral hepatitis (usually A or B), and acute fatty liver of pregnancy. The symptoms of acute liver failure include jaundice, raised prothrombin time, hypoalbuminaemia, hepatic encephalopathy, and hepatorenal syndrome. It is important to note that liver function tests may not always accurately reflect the synthetic function of the liver, and it is best to assess the prothrombin time and albumin level to determine the severity of the condition. Understanding acute liver failure is crucial in managing and treating this potentially life-threatening condition.
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This question is part of the following fields:
- Gastrointestinal System
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Question 26
Incorrect
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A follow-up study is conducted to examine the weight of 100 adults who were given steroids during their teenage years. The average weight of the adults is 70kg, with a standard deviation of 8 kg. What is the standard error of the mean?
Your Answer: 0.16
Correct Answer: 1.6
Explanation:To calculate the standard error of the mean, divide the standard deviation by the square root of the number of patients. For example, if the standard deviation is 16 and there are 100 patients, the standard error of the mean would be 1.6.
Understanding Confidence Interval and Standard Error of the Mean
The confidence interval is a widely used concept in medical statistics, but it can be confusing to understand. In simple terms, it is a range of values that is likely to contain the true effect of an intervention. The likelihood of the true effect lying within the confidence interval is determined by the confidence level, which is the specified probability of including the true value of the variable. For instance, a 95% confidence interval means that the range of values should contain the true effect of intervention 95% of the time.
To calculate the confidence interval, we use the standard error of the mean (SEM), which measures the spread expected for the mean of the observations. The SEM is calculated by dividing the standard deviation (SD) by the square root of the sample size (n). As the sample size increases, the SEM gets smaller, indicating a more accurate sample mean from the true population mean.
A 95% confidence interval is calculated by subtracting and adding 1.96 times the SEM from the mean value. However, if the sample size is small (n < 100), a 'Student's T critical value' look-up table should be used instead of 1.96. Similarly, if a different confidence level is required, such as 90%, the value used in the formula should be adjusted accordingly. In summary, the confidence interval is a range of values that is likely to contain the true effect of an intervention, and its calculation involves using the standard error of the mean. Understanding these concepts is crucial in interpreting statistical results in medical research.
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This question is part of the following fields:
- General Principles
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Question 27
Correct
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A 70-year-old male arrives at the emergency department complaining of tearing chest pain that radiates to his back. He has a history of uncontrolled hypertension. During auscultation, a diastolic murmur is heard, which is most audible over the 2nd intercostal space, right sternal border. What chest radiograph findings are expected from this patient's presentation?
Your Answer: Widened mediastinum
Explanation:Aortic dissection can cause a widened mediastinum on a chest x-ray. This condition is characterized by tearing chest pain that radiates to the back, hypertension, and aortic regurgitation. It occurs when there is a tear in the tunica intima of the aorta’s wall, creating a false lumen that fills with a large volume of blood.
Calcification of the arch of the aorta, cardiomegaly, displacement of the trachea from the midline, and enlargement of the aortic knob are not commonly associated with aortic dissection. Calcification of the walls of arteries is a chronic process that occurs with age and is more likely in men. Cardiomegaly can be caused by various conditions, including ischaemic heart disease and congenital abnormalities. Displacement of the trachea from the midline can result from other pathologies such as a tension pneumothorax or an aortic aneurysm. Enlargement of the aortic knob is a classical finding of an aortic aneurysm.
Aortic dissection is classified according to the location of the tear in the aorta. The Stanford classification divides it into type A, which affects the ascending aorta in two-thirds of cases, and type B, which affects the descending aorta distal to the left subclavian origin in one-third of cases. The DeBakey classification divides it into type I, which originates in the ascending aorta and propagates to at least the aortic arch and possibly beyond it distally, type II, which originates in and is confined to the ascending aorta, and type III, which originates in the descending aorta and rarely extends proximally but will extend distally.
To diagnose aortic dissection, a chest x-ray may show a widened mediastinum, but CT angiography of the chest, abdomen, and pelvis is the investigation of choice. However, the choice of investigations should take into account the patient’s clinical stability, as they may present acutely and be unstable. Transoesophageal echocardiography (TOE) is more suitable for unstable patients who are too risky to take to the CT scanner.
The management of type A aortic dissection is surgical, but blood pressure should be controlled to a target systolic of 100-120 mmHg while awaiting intervention. On the other hand, type B aortic dissection is managed conservatively with bed rest and IV labetalol to reduce blood pressure and prevent progression. Complications of a backward tear include aortic incompetence/regurgitation and MI, while complications of a forward tear include unequal arm pulses and BP, stroke, and renal failure. Endovascular repair of type B aortic dissection may have a role in the future.
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This question is part of the following fields:
- Cardiovascular System
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Question 28
Correct
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An 80-year-old white woman visits her GP with complaints of stiffness, pain, and swelling in her hands. The symptoms are more severe in the morning and gradually improve throughout the day. She has a medical history of hypertension and gout. She admits to taking her husband's prednisolone tablets occasionally to manage her symptoms.
What risk factors does this patient have for the probable diagnosis?Your Answer: Female sex
Explanation:Rheumatoid arthritis is more prevalent in female patients, with a 3-fold higher incidence compared to males. It is characterized by symmetrical pain and stiffness, particularly in the morning. Rheumatoid arthritis can affect individuals of any age and is treated with medications such as prednisolone. Contrary to popular belief, gout does not increase the likelihood of developing rheumatoid arthritis. Additionally, ethnicity, specifically being of white descent, is not considered a risk factor for this condition.
Understanding the Epidemiology of Rheumatoid Arthritis
Rheumatoid arthritis is a chronic autoimmune disease that affects people of all ages, but it typically peaks between the ages of 30 and 50. The condition is more common in women, with a female-to-male ratio of 3:1. The prevalence of rheumatoid arthritis is estimated to be around 1% of the population. However, there are some ethnic differences in the incidence of the disease, with Native Americans having a higher prevalence than other groups.
Researchers have identified a genetic link to rheumatoid arthritis, with the HLA-DR4 gene being associated with the development of the condition. This gene is particularly linked to a subtype of rheumatoid arthritis known as Felty’s syndrome. Understanding the epidemiology of rheumatoid arthritis is important for healthcare professionals to provide appropriate care and support to those affected by the disease. By identifying risk factors and understanding the prevalence of the condition, healthcare providers can better tailor their treatment plans to meet the needs of their patients.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 29
Incorrect
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A 44-year-old woman arrives at the Emergency Department with intermittent sharp pain in her right flank and haematuria. She reports feeling slightly nauseous, but otherwise feels well. She has a medical history of hyperparathyroidism, but has never experienced these symptoms before. Her body mass index is 28kg/m² and she admits to regularly consuming takeaways. During examination, she appears restless and exhibits tenderness in her right flank.
What is the probable substance responsible for causing this patient's pain?Your Answer: Struvite
Correct Answer: Calcium oxalate
Explanation:Renal stones are predominantly made up of calcium phosphate, and individuals with renal tubular acidosis are at a higher risk of developing them. Uric acid stones, which make up only 5-10% of cases, are often associated with malignancies.
Renal stones can be classified into different types based on their composition. Calcium oxalate stones are the most common, accounting for 85% of all calculi. These stones are formed due to hypercalciuria, hyperoxaluria, and hypocitraturia. They are radio-opaque and may also bind with uric acid stones. Cystine stones are rare and occur due to an inherited recessive disorder of transmembrane cystine transport. Uric acid stones are formed due to purine metabolism and may precipitate when urinary pH is low. Calcium phosphate stones are associated with renal tubular acidosis and high urinary pH. Struvite stones are formed from magnesium, ammonium, and phosphate and are associated with chronic infections. The pH of urine can help determine the type of stone present, with calcium phosphate stones forming in normal to alkaline urine, uric acid stones forming in acidic urine, and struvate stones forming in alkaline urine. Cystine stones form in normal urine pH.
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This question is part of the following fields:
- Renal System
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Question 30
Incorrect
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What is the primary process of growth that causes benign enlargement of the prostate?
Your Answer: Hypertrophy
Correct Answer: Hyperplasia
Explanation:Benign Prostatic Hyperplasia
Benign prostatic hyperplasia (BPH) is a common condition that affects men as they age. It is characterized by an increase in the number of cells in the prostate gland, which leads to its enlargement. This process is known as hyperplasia and is the main method for age-related prostate enlargement. BPH is caused by an increase in the number of exocrine glands and ducts, which are structurally normal.
Hypertrophy, which is an increase in the size of cells, also plays a role in BPH, but to a lesser extent. It mainly affects the central (periurethral) zone of the prostate, causing urethral compression and the symptoms of bladder outlet obstruction. On the other hand, dysplasia, which is the abnormal growth of cells, is more likely to occur in the peripheral zone of the prostate. This area has the potential to develop into malignancy, making it important to monitor any changes in the prostate gland. the mechanisms behind BPH can help in the diagnosis and management of this condition.
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This question is part of the following fields:
- Clinical Sciences
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