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Question 1
Correct
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A 26-year-old woman presents to the emergency department with complaints of severe abdominal pain, polyuria, polydipsia, and lethargy. The pain started suddenly 2 hours ago and is spread across her entire abdomen. She has a medical history of appendicectomy eight years ago and type 1 diabetes mellitus. Upon examination, her pH is 7.25 (normal range: 7.35-7.45) and bicarbonate is 9 mmol/L (normal range: 22-29mmol/L). What additional investigations are necessary to confirm the most probable diagnosis?
Your Answer: Blood ketones
Explanation:Abdominal pain can be an initial symptom of DKA, which is the most probable diagnosis in this case. The patient’s symptoms, including abdominal pain, strongly suggest DKA. Blood ketones are the appropriate investigation as they are part of the diagnostic criteria for DKA, along with pH and bicarbonate.
Amylase could help rule out acute pancreatitis, but it is not the most likely diagnosis, so it would not confirm it. Pancreatitis typically presents with severe upper abdominal pain and vomiting. Polydipsia and polyuria are more indicative of DKA, and the patient’s known history of type 1 diabetes mellitus makes DKA more likely.
Beta-hCG would be an appropriate investigation for abdominal pain in a woman of childbearing age, but it is not necessary in this case as DKA is the most likely diagnosis.
Blood glucose levels would be useful if the patient were not a known type 1 diabetic, but they do not form part of the diagnostic criteria for DKA. Blood glucose levels would also be helpful in distinguishing between DKA and HHS, but HHS is unlikely in this case as it occurs in patients with type 2 diabetes.
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 2
Correct
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A 3 day old infant is found to have difficulty urinating and upon closer examination, is diagnosed with hypospadias. What is the most frequently associated abnormality with this condition?
Your Answer: Cryptorchidism
Explanation:Understanding Hypospadias: A Congenital Abnormality of the Penis
Hypospadias is a congenital abnormality of the penis that affects approximately 3 out of 1,000 male infants. It is usually identified during the newborn baby check, but if missed, parents may notice an abnormal urine stream. This condition is characterized by a ventral urethral meatus, a hooded prepuce, and chordee in more severe forms. In some cases, the urethral meatus may open more proximally in the more severe variants, but 75% of the openings are distally located.
There appears to be a significant genetic element to hypospadias, with further male children having a risk of around 5-15%. While it most commonly occurs as an isolated disorder, associated conditions include cryptorchidism (present in 10%) and inguinal hernia.
Once hypospadias has been identified, infants should be referred to specialist services. Corrective surgery is typically performed when the child is around 12 months of age. It is essential that the child is not circumcised prior to the surgery as the foreskin may be used in the corrective procedure. In boys with very distal disease, no treatment may be needed.
Overall, understanding hypospadias is important for parents and healthcare providers to ensure proper management and treatment for affected infants.
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This question is part of the following fields:
- Endocrine System
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Question 3
Correct
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A 32-year-old woman comes to the clinic complaining of fatigue and weight loss that has been going on for 6 weeks. She reports feeling dizzy when she stands up and has noticed a tan all over her body, despite it being early spring in the UK.
Upon conducting a blood test, it is found that she has hyponatraemia and hyperkalaemia, with normal full blood count results. A lying-standing blood pressure reading shows a postural drop of 36 mmHg.
What is the most likely cause of this woman's presentation in the UK, given her symptoms and test results?Your Answer: Autoimmune adrenal insufficiency
Explanation:The most likely cause of this patient’s symptoms is autoimmune adrenalitis, which is responsible for the majority of cases of hypoadrenalism. In this condition, auto-antibodies attack the adrenal gland, leading to a decrease or complete loss of cortisol and aldosterone production. This results in low blood pressure, electrolyte imbalances, and a significant drop in blood pressure upon standing. The body compensates for the low cortisol levels by producing more adrenocorticotropic hormone (ACTH), which can cause the skin to take on a bronze hue.
While iodine deficiency is a common cause of hypothyroidism worldwide, it is not consistent with this patient’s presentation. A mutation in the HFE gene can lead to haemochromatosis, which can cause reduced libido and skin darkening, but it does not match the electrolyte abnormalities described. Pituitary tumors and tuberculosis can also cause hypoadrenalism, but they are less common in the UK compared to autoimmune causes.
Addison’s disease is the most common cause of primary hypoadrenalism in the UK, with autoimmune destruction of the adrenal glands being the main culprit, accounting for 80% of cases. This results in reduced production of cortisol and aldosterone. Symptoms of Addison’s disease include lethargy, weakness, anorexia, nausea and vomiting, weight loss, and salt-craving. Hyperpigmentation, especially in palmar creases, vitiligo, loss of pubic hair in women, hypotension, hypoglycemia, and hyponatremia and hyperkalemia may also be observed. In severe cases, a crisis may occur, leading to collapse, shock, and pyrexia.
Other primary causes of hypoadrenalism include tuberculosis, metastases (such as bronchial carcinoma), meningococcal septicaemia (Waterhouse-Friderichsen syndrome), HIV, and antiphospholipid syndrome. Secondary causes include pituitary disorders, such as tumours, irradiation, and infiltration. Exogenous glucocorticoid therapy can also lead to hypoadrenalism.
It is important to note that primary Addison’s disease is associated with hyperpigmentation, while secondary adrenal insufficiency is not.
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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 67-year-old male presents to the respiratory clinic for the management of his COPD. He has a history of multiple courses of prednisolone, but has recently experienced significant weight gain, facial redness, and elevated blood pressure of 180/96 mmHg. The physician suspects Cushing syndrome due to exogenous steroid use and decides to discontinue the prescription. What is the specific region of the adrenal gland responsible for producing glucocorticoids?
Your Answer: Zona fasciculata
Explanation:Cortisol: Functions and Regulation
Cortisol is a hormone produced in the zona fasciculata of the adrenal cortex. It plays a crucial role in various bodily functions and is essential for life. Cortisol increases blood pressure by up-regulating alpha-1 receptors on arterioles, allowing for a normal response to angiotensin II and catecholamines. However, it inhibits bone formation by decreasing osteoblasts, type 1 collagen, and absorption of calcium from the gut, while increasing osteoclastic activity. Cortisol also increases insulin resistance and metabolism by increasing gluconeogenesis, lipolysis, and proteolysis. It inhibits inflammatory and immune responses, but maintains the function of skeletal and cardiac muscle.
The regulation of cortisol secretion is controlled by the hypothalamic-pituitary-adrenal (HPA) axis. The pituitary gland secretes adrenocorticotropic hormone (ACTH), which stimulates the adrenal cortex to produce cortisol. The hypothalamus releases corticotrophin-releasing hormone (CRH), which stimulates the pituitary gland to release ACTH. Stress can also increase cortisol secretion.
Excess cortisol in the body can lead to Cushing’s syndrome, which can cause a range of symptoms such as weight gain, muscle weakness, and high blood pressure. Understanding the functions and regulation of cortisol is important for maintaining overall health and preventing hormonal imbalances.
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This question is part of the following fields:
- Endocrine System
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Question 5
Correct
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A 23-year-old female patient visits her GP clinic due to her struggle with weight loss. Her BMI is almost 40 kg/m², which is severely impacting her mental and physical well-being. Despite following a strict diet and exercise routine, she has not seen any significant improvement. The GP decides to prescribe orlistat as an anti-obesity medication.
What is the mechanism of action of orlistat in promoting weight loss?Your Answer: Reduces fat digestion by inhibiting lipase
Explanation:Orlistat functions by inhibiting gastric and pancreatic lipase, which reduces the digestion of fat.
2,4-Dinitrophenol (DNP) induces mitochondrial uncoupling and can result in weight loss without calorie reduction. However, it is hazardous when used improperly and is not prescribed outside of the US.
Weight gain can be caused by increased insulin secretion.
Orlistat reduces fat digestion by inhibiting lipase, which decreases the amount of fat that can be absorbed. This can result in light-colored, floating stools due to the high fat content.
Liraglutide is a medication that slows gastric emptying to increase satiety and is primarily prescribed as an adjunct in type 2 diabetics.
Serotonin reuptake inhibitors are not utilized for weight loss.
Obesity can be managed through a step-wise approach that includes conservative, medical, and surgical options. The first step is usually conservative, which involves implementing changes in diet and exercise. If this is not effective, medical options such as Orlistat may be considered. Orlistat is a pancreatic lipase inhibitor that is used to treat obesity. However, it can cause adverse effects such as faecal urgency/incontinence and flatulence. A lower dose version of Orlistat is now available without prescription, known as ‘Alli’. The National Institute for Health and Care Excellence (NICE) has defined criteria for the use of Orlistat. It should only be prescribed as part of an overall plan for managing obesity in adults who have a BMI of 28 kg/m^2 or more with associated risk factors, or a BMI of 30 kg/m^2 or more, and continued weight loss of at least 5% at 3 months. Orlistat is typically used for less than one year.
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This question is part of the following fields:
- Endocrine System
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Question 6
Correct
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A 38-year-old woman presents to the Emergency Department with a 2-day history of left flank pain. She has been recently diagnosed with osteoporosis after a low-energy, femoral neck fracture.
Her blood results show the following:
Na+ 140 mmol/L (135 - 145)
K+ 3.6 mmol/L (3.5 - 5.0)
Calcium 2.9 mmol/L (2.1-2.6)
Phosphate 0.6 mmol/L (0.8-1.4)
Her urine dip is positive for erythrocytes making a diagnosis of renal calculi likely.
What is the pathophysiological reason for the low serum phosphate level, given the likely underlying pathology?Your Answer: Decreased renal phosphate reabsorption
Explanation:The decrease in renal phosphate reabsorption is caused by PTH.
The symptoms presented are indicative of a kidney stone, which can be a sign of hyperparathyroidism. Primary hyperparathyroidism, caused by a functioning parathyroid adenoma, can result in low phosphate and high calcium levels. PTH reduces renal phosphate reabsorption, leading to increased phosphate loss in urine. Pituitary adenomas are associated with osteoporosis due to excessive PTH causing bone resorption.
PTH activates vitamin D, which increases phosphate absorption in the gastrointestinal tract. However, the renal loss of phosphate is greater than the increase in absorption, resulting in a net loss of phosphate when PTH levels are high.
PTH also increases renal vitamin D activation, leading to increased intestinal absorption of calcium and phosphate, as well as increased osteoclast activity. This results in elevated levels of serum calcium and phosphate.
Hypothyroidism does not significantly affect phosphate regulation, so it would not cause low serum phosphate levels.
Increased osteoclast activity caused by PTH leads to bone resorption and the release of calcium and phosphate into the blood. However, the renal loss of phosphate is greater than the increase in serum phosphate due to osteoclast activity, resulting in an overall decrease in serum phosphate levels.
Understanding Parathyroid Hormone and Its Effects
Parathyroid hormone is a hormone produced by the chief cells of the parathyroid glands. Its main function is to increase the concentration of calcium in the blood by stimulating the PTH receptors in the kidney and bone. This hormone has a short half-life of only 4 minutes.
The effects of parathyroid hormone are mainly seen in the bone, kidney, and intestine. In the bone, PTH binds to osteoblasts, which then signal to osteoclasts to resorb bone and release calcium. In the kidney, PTH promotes the active reabsorption of calcium and magnesium from the distal convoluted tubule, while decreasing the reabsorption of phosphate. In the intestine, PTH indirectly increases calcium absorption by increasing the activation of vitamin D, which in turn increases calcium absorption.
Overall, understanding the role of parathyroid hormone is important in maintaining proper calcium levels in the body. Any imbalances in PTH secretion can lead to various disorders such as hyperparathyroidism or hypoparathyroidism.
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This question is part of the following fields:
- Endocrine System
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Question 7
Correct
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As a medical student on community care placement, I was shadowing a health visitor who measured the height and weight of all the children to monitor their growth. I was curious to know what drives growth during the adolescent stage (13 to 19 years old)?
Your Answer: Sex steroids and growth hormone
Explanation:Understanding Growth and Factors Affecting It
Growth is a significant difference between children and adults, and it occurs in three stages: infancy, childhood, and puberty. Several factors affect fetal growth, including environmental, placental, hormonal, and genetic factors. Maternal nutrition and uterine capacity are the most crucial environmental factors that affect fetal growth.
In infancy, nutrition and insulin are the primary drivers of growth. High fetal insulin levels result from poorly controlled diabetes in the mother, leading to hypoglycemia and macrosomia in the baby. Growth hormone is not a significant factor in infancy, as babies have low amounts of receptors. Hypopituitarism and thyroid have no effect on growth in infancy.
In childhood, growth is driven by growth hormone and thyroxine, while in puberty, growth is driven by growth hormone and sex steroids. Genetic factors are the most important determinant of final adult height.
It is essential to monitor growth in children regularly. Infants aged 0-1 years should have at least five weight recordings, while children aged 1-2 years should have at least three weight recordings. Children older than two years should have annual weight recordings. Children below the 2nd centile for height should be reviewed by their GP, while those below the 0.4th centile for height should be reviewed by a paediatrician.
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This question is part of the following fields:
- Endocrine System
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Question 8
Correct
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A 49-year-old woman has been diagnosed with a phaeochromocytoma. What is the primary amino acid from which catecholamines are derived?
Your Answer: Tyrosine
Explanation:Tyrosine serves as the precursor for catecholamine hormones, which undergo modification by a DOPA decarboxylase enzyme to form dopamine. Subsequently, through two additional enzymatic alterations, dopamine is converted to noradrenaline and ultimately adrenaline.
Adrenal Physiology: Medulla and Cortex
The adrenal gland is composed of two main parts: the medulla and the cortex. The medulla is responsible for secreting the catecholamines noradrenaline and adrenaline, which are released in response to sympathetic nervous system stimulation. The chromaffin cells of the medulla are innervated by the splanchnic nerves, and the release of these hormones is triggered by the secretion of acetylcholine from preganglionic sympathetic fibers. Phaeochromocytomas, which are tumors derived from chromaffin cells, can cause excessive secretion of both adrenaline and noradrenaline.
The adrenal cortex is divided into three distinct zones: the zona glomerulosa, zona fasciculata, and zona reticularis. Each zone is responsible for secreting different hormones. The outer zone, zona glomerulosa, secretes aldosterone, which regulates electrolyte balance and blood pressure. The middle zone, zona fasciculata, secretes glucocorticoids, which are involved in the regulation of metabolism, immune function, and stress response. The inner zone, zona reticularis, secretes androgens, which are involved in the development and maintenance of male sex characteristics.
Most of the hormones secreted by the adrenal cortex, including glucocorticoids and aldosterone, are bound to plasma proteins in the circulation. Glucocorticoids are inactivated and excreted by the liver. Understanding the physiology of the adrenal gland is important for the diagnosis and treatment of various endocrine disorders.
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This question is part of the following fields:
- Endocrine System
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Question 9
Correct
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A 43-year-old obese man comes to your clinic for a diabetes check-up. Despite being treated with metformin and gliclazide, his HbA1c remains elevated at 55 mmol/mol. He has previously found it difficult to follow dietary advice and lose weight. To enhance his diabetic management, you prescribe sitagliptin, a DPP-4 inhibitor. What is the mode of action of this novel medication?
Your Answer: Inhibits the breakdown of incretins
Explanation:DPP-4 inhibitors, GLP-1 agonists, SGLT-2 inhibitors, thiazolidinediones, and sulfonylureas are all medications used to treat diabetes. DPP-4 inhibitors work by inhibiting the breakdown of incretins such as GLP-1 and GIP, which are released in response to food and help to lower blood glucose levels. GLP-1 agonists directly stimulate incretin receptors, while SGLT-2 inhibitors increase the urinary secretion of glucose. Thiazolidinediones stimulate intracellular signaling molecules responsible for glucose and lipid metabolism, and sulfonylureas stimulate beta cells to secrete more insulin. However, sulfonylureas may be less effective in long-standing diabetes as many beta cells may no longer function properly.
Diabetes mellitus is a condition that has seen the development of several drugs in recent years. One hormone that has been the focus of much research is glucagon-like peptide-1 (GLP-1), which is released by the small intestine in response to an oral glucose load. In type 2 diabetes mellitus (T2DM), insulin resistance and insufficient B-cell compensation occur, and the incretin effect, which is largely mediated by GLP-1, is decreased. GLP-1 mimetics, such as exenatide and liraglutide, increase insulin secretion and inhibit glucagon secretion, resulting in weight loss, unlike other medications. They are sometimes used in combination with insulin in T2DM to minimize weight gain. Dipeptidyl peptidase-4 (DPP-4) inhibitors, such as vildagliptin and sitagliptin, increase levels of incretins by decreasing their peripheral breakdown, are taken orally, and do not cause weight gain. Nausea and vomiting are the major adverse effects of GLP-1 mimetics, and the Medicines and Healthcare products Regulatory Agency has issued specific warnings on the use of exenatide, reporting that it has been linked to severe pancreatitis in some patients. NICE guidelines suggest that a DPP-4 inhibitor might be preferable to a thiazolidinedione if further weight gain would cause significant problems, a thiazolidinedione is contraindicated, or the person has had a poor response to a thiazolidinedione.
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This question is part of the following fields:
- Endocrine System
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Question 10
Correct
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A 38-year-old woman presents with symptoms of irritability and changes in bowel habits. During examination, a smooth enlargement of the thyroid gland is noted. Thyroid function tests are ordered and the results are as follows:
TSH 0.1 mug/l
Free T4 35 pmol/l
What is the most likely underlying diagnosis?Your Answer: Graves disease
Explanation:When TSH receptor antibodies are present, they stimulate the thyroid to produce T4. This results in a decrease in TSH levels due to negative feedback on the pituitary. However, in cases where hyperthyroidism is caused by pregnancy, the TSH levels are usually elevated.
Understanding Thyroid Disease and its Management
Thyroid disease can present with various manifestations, which can be classified based on the presence or absence of clinical signs of thyroid dysfunction and the presence of a mass. To assess thyroid disease, a thorough history and examination, including ultrasound, are necessary. If a nodule is identified, it should be sampled through an image-guided fine needle aspiration. Radionucleotide scanning is not very useful.
Thyroid tumors can be papillary, follicular, anaplastic, medullary, or lymphoma. Multinodular goitre is a common reason for presentation, and if the patient is asymptomatic and euthyroid, they can be reassured. However, if they have compressive symptoms, surgery is required, and total thyroidectomy is the best option. Patients with endocrine dysfunction are initially managed by physicians, and surgery may be offered alongside radioiodine for those with Graves disease that fails with medical management or in patients who prefer not to be irradiated. Patients with hypothyroidism do not generally get offered a thyroidectomy.
Complications following surgery include anatomical damage to the recurrent laryngeal nerve, bleeding, and damage to the parathyroid glands resulting in hypocalcaemia. For further information, the Association of Clinical Biochemistry guidelines for thyroid function tests and the British Association of Endocrine Surgeons website can be consulted.
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This question is part of the following fields:
- Endocrine System
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Question 11
Incorrect
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A 65-year-old man with type 2 diabetes mellitus has been taking metformin 1g twice daily for the past 6 months. Despite this, his HbA1c has remained above target at 64 mmol/mol (8.0%).
He has a history of left ventricular failure following a myocardial infarction 2 years ago. He has been trying to lose weight since but still has a body mass index of 33 kg/m². He is also prone to recurrent urinary tract infections.
You intend to intensify treatment by adding a second medication.
What is the mechanism of action of the most appropriate anti-diabetic drug for him?Your Answer: Inhibition of renal sodium-glucose co-transporter-2 (SGLT2) to increase glucose excretion
Correct Answer: Inhibition of dipeptidyl peptidase-4 (DPP-4) to increase incretin levels
Explanation:Diabetes mellitus is a condition that has seen the development of several drugs in recent years. One hormone that has been the focus of much research is glucagon-like peptide-1 (GLP-1), which is released by the small intestine in response to an oral glucose load. In type 2 diabetes mellitus (T2DM), insulin resistance and insufficient B-cell compensation occur, and the incretin effect, which is largely mediated by GLP-1, is decreased. GLP-1 mimetics, such as exenatide and liraglutide, increase insulin secretion and inhibit glucagon secretion, resulting in weight loss, unlike other medications. They are sometimes used in combination with insulin in T2DM to minimize weight gain. Dipeptidyl peptidase-4 (DPP-4) inhibitors, such as vildagliptin and sitagliptin, increase levels of incretins by decreasing their peripheral breakdown, are taken orally, and do not cause weight gain. Nausea and vomiting are the major adverse effects of GLP-1 mimetics, and the Medicines and Healthcare products Regulatory Agency has issued specific warnings on the use of exenatide, reporting that it has been linked to severe pancreatitis in some patients. NICE guidelines suggest that a DPP-4 inhibitor might be preferable to a thiazolidinedione if further weight gain would cause significant problems, a thiazolidinedione is contraindicated, or the person has had a poor response to a thiazolidinedione.
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This question is part of the following fields:
- Endocrine System
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Question 12
Correct
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A 22-year-old male presents to the emergency department with a two-hour history of nausea, confusion, and drowsiness. The patient has a medical history of type 1 diabetes mellitus.
Upon conducting an A-E examination, the only significant finding is a plasma glucose level of 3.4 mmol/L. The patient is capable of swallowing.
What is the most suitable course of action for managing this patient?Your Answer: Two tubes of oral glucose gel
Explanation:The recommended first-line treatment for a conscious patient with hypoglycaemia is a fast-acting carbohydrate taken orally, such as glucose liquids, tablets, or gels. In this case, the appropriate course of action would be to administer two tubes of glucose gel. Glucagon via intramuscular injection is not necessary unless the patient is experiencing severe hypoglycaemia or is unable to swallow. Insulin via intramuscular injection is not appropriate for treating hypoglycaemia, and intravenous glucose is only used in cases of severe hypoglycaemia.
Understanding Hypoglycaemia: Causes, Features, and Management
Hypoglycaemia is a condition characterized by low blood sugar levels, which can lead to a range of symptoms and complications. There are several possible causes of hypoglycaemia, including insulinoma, liver failure, Addison’s disease, and alcohol consumption. The physiological response to hypoglycaemia involves hormonal and sympathoadrenal responses, which can result in autonomic and neuroglycopenic symptoms. While blood glucose levels and symptom severity are not always correlated, common symptoms of hypoglycaemia include sweating, shaking, hunger, anxiety, nausea, weakness, vision changes, confusion, and dizziness. In severe cases, hypoglycaemia can lead to convulsions or coma.
Managing hypoglycaemia depends on the severity of the symptoms and the setting in which it occurs. In the community, individuals with diabetes who inject insulin may be advised to consume oral glucose or a quick-acting carbohydrate such as GlucoGel or Dextrogel. A ‘HypoKit’ containing glucagon may also be prescribed for home use. In a hospital setting, treatment may involve administering a quick-acting carbohydrate or subcutaneous/intramuscular injection of glucagon for unconscious or unable to swallow patients. Alternatively, intravenous glucose solution may be given through a large vein.
Overall, understanding the causes, features, and management of hypoglycaemia is crucial for individuals with diabetes or other conditions that increase the risk of low blood sugar levels. Prompt and appropriate treatment can help prevent complications and improve outcomes.
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This question is part of the following fields:
- Endocrine System
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Question 13
Correct
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A 20-year-old man comes to the emergency department complaining of abdominal pain, vomiting, polyuria, polydipsia, and confusion that have been present for the past 12 hours. During the examination, he shows mild generalized abdominal tenderness without guarding. His breathing is observed to be deep and rapid.
The patient has a medical history of type 1 diabetes, but he confesses to being non-compliant with his insulin regimen.
What is the probable pathophysiology behind his symptoms?Your Answer: Uncontrolled lipolysis which results in an excess of free fatty acids
Explanation:The cause of DKA is uncontrolled lipolysis, leading to an excess of free fatty acids that are converted to ketone bodies. This results in high levels of ketones in the urine. Hypoglycemia activates the sympathetic nervous system. Lactic acidosis is similar to DKA but lacks the presence of ketones in urine. Appendicitis can cause abdominal pain, vomiting, and urinary symptoms, but the presence of ketones in urine suggests DKA. Urinary tract infections are rare in men under 50 and typically occur with abnormal anatomy or catheterization.
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 14
Incorrect
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A 50-year-old man has a laparotomy and repair of incisional hernia. Which hormone is most unlikely to be released in higher amounts after the surgery?
Your Answer: ACTH
Correct Answer: Insulin
Explanation:Reduced secretion of insulin and thyroxine is common after surgery, which can make it challenging to manage diabetes in people with insulin resistance due to the additional release of glucocorticoids.
Surgery triggers a stress response that causes hormonal and metabolic changes in the body. This response is characterized by substrate mobilization, muscle protein loss, sodium and water retention, suppression of anabolic hormone secretion, activation of the sympathetic nervous system, and immunological and haematological changes. The hypothalamic-pituitary axis and the sympathetic nervous systems are activated, and the normal feedback mechanisms of control of hormone secretion fail. The stress response is associated with increased growth hormone, cortisol, renin, adrenocorticotrophic hormone (ACTH), aldosterone, prolactin, antidiuretic hormone, and glucagon, while insulin, testosterone, oestrogen, thyroid stimulating hormone, luteinizing hormone, and follicle stimulating hormone are decreased or remain unchanged. The metabolic effects of cortisol are enhanced, including skeletal muscle protein breakdown, stimulation of lipolysis, anti-insulin effect, mineralocorticoid effects, and anti-inflammatory effects. The stress response also affects carbohydrate, protein, lipid, salt and water metabolism, and cytokine release. Modifying the response can be achieved through opioids, spinal anaesthesia, nutrition, growth hormone, anabolic steroids, and normothermia.
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This question is part of the following fields:
- Endocrine System
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Question 15
Correct
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A 45-year-old male is recovering from trans-sphenoidal surgery for a non-functioning pituitary adenoma. He reports excessive thirst and increased water intake to the doctors during the ward round, four days after the surgery. The patient's fluid chart shows a urine output of 7 litres in the past 24 hours, and his blood glucose level is 5.2mmol/L. To confirm the diagnosis, the doctors plan to conduct a water-deprivation test and a vasopressin test.
What are the expected results of the urine osmolality investigations, given the likely diagnosis?Your Answer: After fluid deprivation, low; after desmopressin, high
Explanation:The patient has developed cranial diabetes insipidus after pituitary surgery. Water deprivation testing showed low urine osmolality after fluid deprivation and high urine osmolality after desmopressin administration. This condition can also be caused by head trauma or occur idiopathically. Water deprivation testing can also be useful for investigating psychogenic polydipsia. Nephrogenic diabetes insipidus is the other main cause, where the kidneys cannot properly respond to vasopressin.
The water deprivation test is a diagnostic tool used to assess patients with polydipsia, or excessive thirst. During the test, the patient is instructed to refrain from drinking water, and their bladder is emptied. Hourly measurements of urine and plasma osmolalities are taken to monitor changes in the body’s fluid balance. The results of the test can help identify the underlying cause of the patient’s polydipsia. Normal results show a high urine osmolality after the administration of DDAVP, while psychogenic polydipsia is characterized by a low urine osmolality. Cranial DI and nephrogenic DI are both associated with high plasma osmolalities and low urine osmolalities.
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This question is part of the following fields:
- Endocrine System
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Question 16
Correct
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A 39-year-old male presents to an endocrine clinic with acromegaly caused by a growth hormone-secreting tumor. The patient is prescribed Octreotide, a somatostatin analogue, to suppress growth hormone release.
What additional hormonal effects can be attributed to somatostatin?Your Answer: Decreases secretion of glucagon
Explanation:Somatostatin has an inhibitory effect on the secretion of glucagon, but it does not affect the secretion of estrogen. It also decreases the secretion of insulin, and overproduction of somatostatin can lead to diabetes mellitus. Additionally, somatostatin reduces the secretion of gastrin, which in turn decreases the production of gastric acid by parietal cells. It also decreases the secretion of thyroid stimulating hormone (TSH), resulting in a decrease in the production of thyroxine in the thyroid.
Somatostatin: The Inhibitor Hormone
Somatostatin, also known as growth hormone inhibiting hormone (GHIH), is a hormone produced by delta cells found in the pancreas, pylorus, and duodenum. Its main function is to inhibit the secretion of growth hormone, insulin, and glucagon. It also decreases acid and pepsin secretion, as well as pancreatic enzyme secretion. Additionally, somatostatin inhibits the trophic effects of gastrin and stimulates gastric mucous production.
Somatostatin analogs are commonly used in the management of acromegaly, a condition characterized by excessive growth hormone secretion. These analogs work by inhibiting growth hormone secretion, thereby reducing the symptoms associated with acromegaly.
The secretion of somatostatin is regulated by various factors. Its secretion increases in response to fat, bile salts, and glucose in the intestinal lumen, as well as glucagon. On the other hand, insulin decreases the secretion of somatostatin.
In summary, somatostatin plays a crucial role in regulating the secretion of various hormones and enzymes in the body. Its inhibitory effects on growth hormone, insulin, and glucagon make it an important hormone in the management of certain medical conditions.
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This question is part of the following fields:
- Endocrine System
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Question 17
Correct
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A 28-year-old female with a three year history of type 1 diabetes complains of sudden confusion and excessive sweating. Upon examination, her pulse is 105 bpm, respiratory rate is 16/min, and she appears disoriented. What would be the most suitable initial test to perform for this patient?
Your Answer: Plasma glucose concentration
Explanation:Differentiating Hypoglycaemia from Diabetic Ketoacidosis in Critically Ill Patients
When assessing a critically ill patient, it is important not to forget the E in the ABCDE algorithm. In the case of a woman presenting acutely, with a normal respiratory rate, it is more likely that she is hypoglycaemic rather than experiencing diabetic ketoacidosis (DKA). To confirm this, it is essential to check her glucose or blood sugar levels and then administer glucose as necessary.
It is crucial to differentiate between hypoglycaemia and DKA as the treatment for each condition is vastly different. While hypoglycaemia requires immediate administration of glucose, DKA requires insulin therapy and fluid replacement. Therefore, a correct diagnosis is essential to ensure the patient receives the appropriate treatment promptly.
In conclusion, when assessing a critically ill patient, it is vital to consider all aspects of the ABCDE algorithm, including the often-overlooked E for exposure. In cases where a patient presents acutely, with a normal respiratory rate, it is essential to differentiate between hypoglycaemia and DKA by checking glucose levels and administering glucose or insulin therapy accordingly.
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This question is part of the following fields:
- Endocrine System
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Question 18
Incorrect
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What is the half life of insulin in the circulation of a typical healthy adult?
Your Answer: Between 2 and 3 hours
Correct Answer: Less than 30 minutes
Explanation:Enzymes in the bloodstream break down insulin, resulting in a half-life of under 30 minutes. In type 2 diabetes, there may be irregularities in the insulin clearance process.
Insulin is a hormone produced by the pancreas that plays a crucial role in regulating the metabolism of carbohydrates and fats in the body. It works by causing cells in the liver, muscles, and fat tissue to absorb glucose from the bloodstream, which is then stored as glycogen in the liver and muscles or as triglycerides in fat cells. The human insulin protein is made up of 51 amino acids and is a dimer of an A-chain and a B-chain linked together by disulfide bonds. Pro-insulin is first formed in the rough endoplasmic reticulum of pancreatic beta cells and then cleaved to form insulin and C-peptide. Insulin is stored in secretory granules and released in response to high levels of glucose in the blood. In addition to its role in glucose metabolism, insulin also inhibits lipolysis, reduces muscle protein loss, and increases cellular uptake of potassium through stimulation of the Na+/K+ ATPase pump.
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This question is part of the following fields:
- Endocrine System
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Question 19
Correct
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A 37-year-old British female presents to her GP with a diagnosis of hypothyroidism. She has resided in the UK her entire life and has a lengthy history of insulin-dependent diabetes, which was diagnosed when she was 9 years old, as well as a recent diagnosis of pernicious anaemia. She maintains a balanced diet, drinks 10 units of alcohol per week, and has been smoking 10 cigarettes per day for the past 16 years. She reports a recent weight gain of 10kg.
During the examination, the GP notes a smooth and enlarged goitre. What is the most probable cause of her hypothyroidism?Your Answer: Hashimoto's thyroiditis
Explanation:Hypothyroidism is a medical condition characterized by insufficient levels of thyroid hormones in the body, which can be caused by issues with the gland or hormones themselves.
Although iodine deficiency is the most common cause of hypothyroidism worldwide, it is unlikely to be the case for a healthy British female with a normal diet.
Medullary cell carcinoma is not a likely cause of hypothyroidism as it typically presents with symptoms such as diarrhea and weight loss.
While smoking can increase the risk of thyroid conditions, it is not a direct cause of hypothyroidism.
Therefore, the possible causes of the patient’s hypothyroidism are narrowed down to either Hashimoto’s disease or a multinodular goiter. However, since the examination revealed a smooth goiter, a multinodular goiter can be ruled out.
Causes of Hypothyroidism
Hypothyroidism is a condition that affects a small percentage of women in the UK, with females being more susceptible than males. The most common cause of hypothyroidism is Hashimoto’s thyroiditis, an autoimmune disease that is often associated with other conditions such as IDDM, Addison’s disease, or pernicious anaemia. Other causes include subacute thyroiditis, Riedel thyroiditis, thyroidectomy or radioiodine treatment, drug therapy, and dietary iodine deficiency. It is important to note that many causes of hypothyroidism may have an initial thyrotoxic phase. Secondary hypothyroidism is rare and can occur due to pituitary failure or other associated conditions such as Down’s syndrome, Turner’s syndrome, or coeliac disease.
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This question is part of the following fields:
- Endocrine System
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Question 20
Incorrect
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A 42-year-old woman complains of fatigue after experiencing flu-like symptoms two weeks ago. Upon examination, she has a smooth, small goiter and a pulse rate of 68 bpm. Her lab results show a Free T4 level of 9.3 pmol/L (normal range: 9.8-23.1) and a TSH level of 49.3 mU/L (normal range: 0.35-5.50). What additional test would you perform to confirm the diagnosis?
Your Answer: No further investigations necessary
Correct Answer: Thyroid peroxidase (TPO) antibodies
Explanation:Diagnosis and Management of Primary Hypothyroidism
The patient’s test results indicate a case of primary hypothyroidism, characterized by low levels of thyroxine (T4) and elevated thyroid-stimulating hormone (TSH). The most likely cause of this condition is Hashimoto’s thyroiditis, which is often accompanied by the presence of thyroid peroxidase antibodies. While the patient has a goitre, it appears to be smooth and non-threatening, so a thyroid ultrasound is not necessary. Additionally, a radio-iodine uptake scan is unlikely to show significant uptake and is therefore not recommended. Positive TSH receptor antibodies are typically associated with Graves’ disease, which is not the likely diagnosis in this case. For further information on Hashimoto’s thyroiditis, patients can refer to Patient.info.
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This question is part of the following fields:
- Endocrine System
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Question 21
Correct
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A 29-year-old female has been diagnosed with hyperthyroidism. She is experiencing heat intolerance and is very frightened by her palpitations. The GP prescribes Carbimazole and a second medication to manage the palpitations. Which receptors are being overstimulated by the increased catecholamine effects in this patient, leading to her palpitations?
Your Answer: β1 receptors
Explanation:The sensitivity of the body to catecholamines is heightened by thyroid hormones. When catecholamines activate the β1 receptors in the heart, it leads to an elevation in heart rate.
Thyroid disorders are commonly encountered in clinical practice, with hypothyroidism and thyrotoxicosis being the most prevalent. Women are ten times more likely to develop these conditions than men. The thyroid gland is a bi-lobed structure located in the anterior neck and is part of a hypothalamus-pituitary-end organ system that regulates the production of thyroxine and triiodothyronine hormones. These hormones help regulate energy sources, protein synthesis, and the body’s sensitivity to other hormones. Hypothyroidism can be primary or secondary, while thyrotoxicosis is mostly primary. Autoimmunity is the leading cause of thyroid problems in the developed world.
Thyroid disorders can present in various ways, with symptoms often being the opposite depending on whether the thyroid gland is under or overactive. For example, hypothyroidism may result in weight gain, while thyrotoxicosis leads to weight loss. Thyroid function tests are the primary investigation for diagnosing thyroid disorders. These tests primarily look at serum TSH and T4 levels, with T3 being measured in specific cases. TSH levels are more sensitive than T4 levels for monitoring patients with existing thyroid problems.
Treatment for thyroid disorders depends on the cause. Patients with hypothyroidism are given levothyroxine to replace the underlying deficiency. Patients with thyrotoxicosis may be treated with propranolol to control symptoms such as tremors, carbimazole to reduce thyroid hormone production, or radioiodine treatment.
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This question is part of the following fields:
- Endocrine System
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Question 22
Correct
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A 59-year-old man with a known history of type-2 diabetes comes for a check-up. He is currently on metformin only for his diabetes and reports compliance with the prescribed regimen.
His HbA1c is 63 mmol/mol (target = 53mmol/mol) and the patient and clinician agree to initiate a sulfonylurea along with his metformin.
What is the primary mode of action of the new treatment?Your Answer: Increases stimulation of insulin secretion by pancreatic B-cells and decreases hepatic clearance of insulin
Explanation:Sulfonylureas are a type of oral hypoglycemic agent that stimulate insulin secretion by pancreatic B-cells and reduce the clearance of insulin by the liver. They are known as insulin secretagogues.
Sulfonylureas are a type of medication used to treat type 2 diabetes mellitus. They work by increasing the amount of insulin produced by the pancreas, but only if the beta cells in the pancreas are functioning properly. Sulfonylureas bind to a specific channel on the cell membrane of pancreatic beta cells, known as the ATP-dependent K+ channel (KATP).
While sulfonylureas can be effective in managing diabetes, they can also cause some adverse effects. The most common side effect is hypoglycemia, which is more likely to occur with long-acting preparations like chlorpropamide. Another common side effect is weight gain. However, there are also rarer side effects that can occur, such as hyponatremia (low sodium levels) due to inappropriate ADH secretion, bone marrow suppression, hepatotoxicity (liver damage), and peripheral neuropathy.
It is important to note that sulfonylureas should not be used during pregnancy or while breastfeeding.
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This question is part of the following fields:
- Endocrine System
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Question 23
Correct
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A 39-year-old, with an elevated BMI and confirmed type II diabetes is attending a clinic for a check-up on his glucose control.
Despite being on treatment for a few months, his latest Hb1Ac and home blood glucose readings are still high. The healthcare provider decides to start the patient on gliclazide. The patient is informed that this medication may cause hypoglycaemia as a side effect by increasing insulin production and release.
Which pancreatic cell membrane channels does gliclazide bind to?Your Answer: ATP-dependent potassium
Explanation:Gliclazide is a medication used to treat diabetes by increasing insulin release from pancreatic beta cells. It works by binding to ATP-dependent potassium channels on these cells, causing depolarization and an increase in intracellular calcium. This leads to the secretion of insulin.
Dipeptidyl peptidase-4 (DDP) inhibitors are another type of medication used to manage diabetes. They work by increasing levels of incretin hormones such as GLP-1 and GIP, which stimulate insulin secretion and decrease blood glucose levels.
Chloride channels are not affected by sulfonylureas, and they play a role in regulating fluid transport in various organs.
Insulin binds to tyrosine kinase receptors on the cell membrane, which triggers a signal transduction pathway that activates enzymes and transcription factors within the cell. Sulfonylureas do not affect these receptors.
Sulfonylureas are a type of medication used to treat type 2 diabetes mellitus. They work by increasing the amount of insulin produced by the pancreas, but only if the beta cells in the pancreas are functioning properly. Sulfonylureas bind to a specific channel on the cell membrane of pancreatic beta cells, known as the ATP-dependent K+ channel (KATP).
While sulfonylureas can be effective in managing diabetes, they can also cause some adverse effects. The most common side effect is hypoglycemia, which is more likely to occur with long-acting preparations like chlorpropamide. Another common side effect is weight gain. However, there are also rarer side effects that can occur, such as hyponatremia (low sodium levels) due to inappropriate ADH secretion, bone marrow suppression, hepatotoxicity (liver damage), and peripheral neuropathy.
It is important to note that sulfonylureas should not be used during pregnancy or while breastfeeding.
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This question is part of the following fields:
- Endocrine System
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Question 24
Correct
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A 35-year-old woman is referred to the endocrine clinic due to missed periods and lactation. She has also gained weight and experiences vaginal dryness. The endocrinologist decides to measure her prolactin levels. What hormone is responsible for suppressing the release of prolactin from the pituitary gland?
Your Answer: Dopamine
Explanation:Dopamine consistently prevents the release of prolactin.
Understanding Prolactin and Its Functions
Prolactin is a hormone that is produced by the anterior pituitary gland. Its primary function is to stimulate breast development and milk production in females. During pregnancy, prolactin levels increase to support the growth and development of the mammary glands. It also plays a role in reducing the pulsatility of gonadotropin-releasing hormone (GnRH) at the hypothalamic level, which can block the action of luteinizing hormone (LH) on the ovaries or testes.
The secretion of prolactin is regulated by dopamine, which constantly inhibits its release. However, certain factors can increase or decrease prolactin secretion. For example, prolactin levels increase during pregnancy, in response to estrogen, and during breastfeeding. Additionally, stress, sleep, and certain drugs like metoclopramide and antipsychotics can also increase prolactin secretion. On the other hand, dopamine and dopaminergic agonists can decrease prolactin secretion.
Overall, understanding the functions and regulation of prolactin is important for reproductive health and lactation.
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This question is part of the following fields:
- Endocrine System
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Question 25
Correct
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A 57-year-old patient presented to her doctor with a complaint of feeling down for the past month. She works as a teacher and has had to take time off as she felt she was not able to perform well in her job. She reports feeling fatigued all the time and has no motivation to engage in her usual activities. She has also noticed some weight gain despite a decreased appetite since she last weighed herself and she observed that her face has become more round. During examination, the doctor finds a pulse of 59 beats per minute, a respiratory rate of 12 breaths per minute, and a blood pressure of 105/63 mmHg. The doctor also notes that the neck region overlying the thyroid gland is symmetrically enlarged but the patient denies any pain or tenderness when the doctor palpated her neck. What is the most likely pathological feature in this patient?
Your Answer: Lymphocytic infiltration of the thyroid gland and the formation of germinal centers
Explanation:The patient’s symptoms and history suggest a diagnosis of hypothyroidism, which is commonly caused by Hashimoto’s thyroiditis in developed countries. This autoimmune condition is more prevalent in women and certain populations, such as the elderly and those with HLA-DR3, 4, and 5 polymorphisms. Other thyroid conditions, such as subacute thyroiditis, Riedel’s thyroiditis, multinodular goitres, and papillary carcinoma, have different characteristic features.
Understanding Hashimoto’s Thyroiditis
Hashimoto’s thyroiditis is a chronic autoimmune disorder that affects the thyroid gland. It is more common in women and is typically associated with hypothyroidism, although there may be a temporary period of thyrotoxicosis during the acute phase. The condition is characterized by a firm, non-tender goitre and the presence of anti-thyroid peroxidase (TPO) and anti-thyroglobulin (Tg) antibodies.
Hashimoto’s thyroiditis is often associated with other autoimmune conditions such as coeliac disease, type 1 diabetes mellitus, and vitiligo. Additionally, there is an increased risk of developing MALT lymphoma with this condition. It is important to note that many causes of hypothyroidism may have an initial thyrotoxic phase, as shown in the Venn diagram. Understanding the features and associations of Hashimoto’s thyroiditis can aid in its diagnosis and management.
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This question is part of the following fields:
- Endocrine System
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Question 26
Correct
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As a medical student observing a metabolic medicine clinic, a 40-year-old woman comes in seeking answers about her obesity. With a BMI of 46 kg/m² and a family history of obesity, she is referred for further investigation. After genetic sequencing, it is discovered that she has a mutation in a hormone-regulating gene that is secreted by adipose tissue.
Which hormone is likely impacted by this genetic mutation?Your Answer: Leptin
Explanation:Leptin is produced by adipose tissue and is responsible for regulating feelings of fullness and satiety. Mutations in the leptin gene can lead to severe obesity in infants due to increased appetite and reduced feelings of satiety. Ghrelin, on the other hand, is a hormone released by the stomach that stimulates hunger. Melatonin, produced by the pineal gland, regulates the sleep-wake cycle and circadian rhythms but is not known to play a significant role in obesity. Obestatin, released by stomach epithelial cells, has a controversial role in obesity.
The Physiology of Obesity: Leptin and Ghrelin
Leptin is a hormone produced by adipose tissue that plays a crucial role in regulating body weight. It acts on the hypothalamus, specifically on the satiety centers, to decrease appetite and induce feelings of fullness. In cases of obesity, where there is an excess of adipose tissue, leptin levels are high. Leptin also stimulates the release of melanocyte-stimulating hormone (MSH) and corticotrophin-releasing hormone (CRH), which further contribute to the regulation of appetite. On the other hand, low levels of leptin stimulate the release of neuropeptide Y (NPY), which increases appetite.
Ghrelin, on the other hand, is a hormone that stimulates hunger. It is mainly produced by the P/D1 cells lining the fundus of the stomach and epsilon cells of the pancreas. Ghrelin levels increase before meals, signaling the body to prepare for food intake, and decrease after meals, indicating that the body has received enough nutrients.
In summary, the balance between leptin and ghrelin plays a crucial role in regulating appetite and body weight. In cases of obesity, there is an imbalance in this system, with high levels of leptin and potentially disrupted ghrelin signaling, leading to increased appetite and weight gain.
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This question is part of the following fields:
- Endocrine System
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Question 27
Correct
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The medical team at a pediatric unit faces difficulty in determining the sex of a newborn baby as the external genitalia appear ambiguous. The suspected condition is linked to an excess of androgen and a deficiency of mineralocorticoid. Can you explain the underlying pathophysiology?
Your Answer: Deficiency of 21-alphahydroxylase
Explanation:The clinical scenario described in the question is indicative of congenital adrenal hyperplasia, which is caused by a deficiency of the enzyme 21-alphahydroxylase. This leads to an increase in androgen production, resulting in virilization of genitalia in XX females, making them appear as males at birth.
On the other hand, a deficiency of 5-alpha reductase causes the opposite situation, where genetically XY males have external female genitalia.
Type 1 diabetes mellitus may be associated with the presence of autoantibodies against glutamic acid decarboxylase.
A defect in the AIRE gene can lead to APECED, which is characterized by hypoparathyroidism, adrenal failure, and candidiasis.
Similarly, a defect in the FOXP3 gene can cause IPEX, which presents with immune dysregulation, polyendocrinopathy, and enteropathy.
Congenital adrenal hyperplasia is a genetic condition that affects the adrenal glands and can result in various symptoms depending on the specific enzyme deficiency. One common form is 21-hydroxylase deficiency, which can cause virilization of female genitalia, precocious puberty in males, and a salt-losing crisis in 60-70% of patients during the first few weeks of life. Another form is 11-beta hydroxylase deficiency, which can also cause virilization and precocious puberty, as well as hypertension and hypokalemia. A third form is 17-hydroxylase deficiency, which typically does not cause virilization in females but can result in intersex characteristics in boys and hypertension.
Overall, congenital adrenal hyperplasia can have significant impacts on a person’s physical development and health, and early diagnosis and treatment are important for managing symptoms and preventing complications.
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This question is part of the following fields:
- Endocrine System
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Question 28
Correct
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An aged woman with malabsorption and weight loss was diagnosed with small bowel amyloidosis. She was initially found to have osteomalacia and hypocalcemia. Despite receiving total parenteral nutrition with sufficient calcium replacement for the past seven days, she remained hypocalcemic. Which electrolyte deficiency is most likely responsible for this condition?
Your Answer: Magnesium
Explanation:Magnesium deficiency may occur in patients with malabsorption, even if they receive magnesium through TPN feeds, as it may not be enough to compensate for their losses. Serum calcium levels are not affected by sodium, phosphate, and potassium.
The Importance of Magnesium and Calcium in the Body
Magnesium and calcium are essential minerals in the body. Magnesium plays a crucial role in the secretion and action of parathyroid hormone (PTH) on target tissues. However, a deficiency in magnesium can cause hypocalcaemia and make patients unresponsive to calcium and vitamin D supplementation.
The body contains 1000 mmol of magnesium, with half stored in bones and the rest in muscle, soft tissues, and extracellular fluid. Unlike calcium, there is no specific hormonal control of magnesium. Hormones such as PTH and aldosterone affect the renal handling of magnesium.
Magnesium and calcium also interact at a cellular level. A decrease in magnesium levels can affect the permeability of cellular membranes to calcium, leading to hyperexcitability. Therefore, it is essential to maintain adequate levels of both magnesium and calcium in the body for optimal health.
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This question is part of the following fields:
- Endocrine System
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Question 29
Incorrect
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A 67-year-old male is undergoing evaluation for Cushing's syndrome. During the assessment, his primary care physician requests a serum cortisol test. In its unbound form, cortisol is responsible for the manifestations of Cushing's syndrome. What is the primary substance that binds to cortisol in the bloodstream, rendering it inactive?
Your Answer: Albumin
Correct Answer: Cortisol binding globulin
Explanation:Cortisol: Functions and Regulation
Cortisol is a hormone produced in the zona fasciculata of the adrenal cortex. It plays a crucial role in various bodily functions and is essential for life. Cortisol increases blood pressure by up-regulating alpha-1 receptors on arterioles, allowing for a normal response to angiotensin II and catecholamines. However, it inhibits bone formation by decreasing osteoblasts, type 1 collagen, and absorption of calcium from the gut, while increasing osteoclastic activity. Cortisol also increases insulin resistance and metabolism by increasing gluconeogenesis, lipolysis, and proteolysis. It inhibits inflammatory and immune responses, but maintains the function of skeletal and cardiac muscle.
The regulation of cortisol secretion is controlled by the hypothalamic-pituitary-adrenal (HPA) axis. The pituitary gland secretes adrenocorticotropic hormone (ACTH), which stimulates the adrenal cortex to produce cortisol. The hypothalamus releases corticotrophin-releasing hormone (CRH), which stimulates the pituitary gland to release ACTH. Stress can also increase cortisol secretion.
Excess cortisol in the body can lead to Cushing’s syndrome, which can cause a range of symptoms such as weight gain, muscle weakness, and high blood pressure. Understanding the functions and regulation of cortisol is important for maintaining overall health and preventing hormonal imbalances.
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This question is part of the following fields:
- Endocrine System
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Question 30
Correct
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A 26-year-old woman with a history of type 1 diabetes mellitus and borderline personality disorder is brought to the emergency department by ambulance due to a decreased level of consciousness. She is currently on regular insulin. Upon examination, her Glasgow coma scale is 3/15. The venous blood gas results show a pH of 7.36 (7.35-7.45), K+ of 3.8 mmol/L (3.5-4.5), Na+ of 136 mmol/L (135-145), glucose of 1.2 mmol/L (4.0-7.0), HCO3- of 23 mmol/L (22-26), and Hb of 145 g/dL (12.1-15.1). What is the first hormone to be secreted in response to the likely diagnosis?
Your Answer: Glucagon
Explanation:The correct answer is Glucagon, as it is the first hormone to be secreted in response to hypoglycaemia. The patient’s reduced level of consciousness is likely due to profound hypoglycaemia caused by exogenous insulin administration. Borderline personality disorder patients have a higher incidence of self harm and suicidality than the general population. Insulin is not the correct answer as its secretion decreases in response to hypoglycaemia, and this patient has T1DM resulting in an absolute deficiency. Cortisol is also not the correct answer as it takes longer to be secreted, although it is another counter-regulatory hormone that seeks to raise blood glucose levels in response to hypoglycaemia.
Understanding Hypoglycaemia: Causes, Features, and Management
Hypoglycaemia is a condition characterized by low blood sugar levels, which can lead to a range of symptoms and complications. There are several possible causes of hypoglycaemia, including insulinoma, liver failure, Addison’s disease, and alcohol consumption. The physiological response to hypoglycaemia involves hormonal and sympathoadrenal responses, which can result in autonomic and neuroglycopenic symptoms. While blood glucose levels and symptom severity are not always correlated, common symptoms of hypoglycaemia include sweating, shaking, hunger, anxiety, nausea, weakness, vision changes, confusion, and dizziness. In severe cases, hypoglycaemia can lead to convulsions or coma.
Managing hypoglycaemia depends on the severity of the symptoms and the setting in which it occurs. In the community, individuals with diabetes who inject insulin may be advised to consume oral glucose or a quick-acting carbohydrate such as GlucoGel or Dextrogel. A ‘HypoKit’ containing glucagon may also be prescribed for home use. In a hospital setting, treatment may involve administering a quick-acting carbohydrate or subcutaneous/intramuscular injection of glucagon for unconscious or unable to swallow patients. Alternatively, intravenous glucose solution may be given through a large vein.
Overall, understanding the causes, features, and management of hypoglycaemia is crucial for individuals with diabetes or other conditions that increase the risk of low blood sugar levels. Prompt and appropriate treatment can help prevent complications and improve outcomes.
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This question is part of the following fields:
- Endocrine System
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