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Question 1
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A 35-year-old hypertensive man presented with the following blood results:
Investigation Result Normal value
Sodium (Na+) 147 mmol/l 135–145 mmol/l
Potassium (K+) 2.8 mmol/l 3.5–5.0 mmol/l
Urea 4.0 mmol/l 2.5–6.5 mmol/l
Creatinine 50 μmol/l 50–120 μmol/l
Glucose 4.0 mmol/l
Random: 3.5–5.5 mmol/l
Fasting: <7 mmol/l
Hba1c: <53 mmol/l (<7.0%)
Which of the following is the most likely diagnosis?Your Answer: Conn's syndrome
Explanation:Differential diagnosis of hypertension with electrolyte abnormalities
When a young patient presents with hypertension and hypokalaemia, it is important to consider secondary causes of hypertension, such as Conn’s syndrome (primary hyperaldosteronism), which can explain both findings. Coarctation of the aorta is another secondary cause of hypertension, but it does not account for the electrolyte abnormalities. Cushing’s disease/syndrome may also present with hypertension and electrolyte abnormalities, but typically with additional symptoms and higher fasting glucose levels. Polycystic kidney disease can cause hypertension, but not the electrolyte abnormalities. Primary (essential) hypertension is the most common form of hypertension, but secondary causes should be ruled out, especially in younger patients with atypical features.
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This question is part of the following fields:
- Endocrinology
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Question 2
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A 55-year-old man is scheduled for colorectal carcinoma resection and has type 2 diabetes. He is currently well-controlled on 5 mg glibenclamide daily. What is the best pre-operative plan for managing his blood sugar levels?
Your Answer: Stop glibenclamide on the morning of surgery and commence insulin by intravenous infusion
Explanation:Management of Glibenclamide in a Patient Undergoing Major Surgery
During major surgery, it is crucial to maintain optimal glycaemic control in patients with diabetes. In the case of a patient taking glibenclamide, the most appropriate course of action is to discontinue the medication on the morning of surgery. Instead, the patient should be started on intravenous (IV) insulin and dextrose with potassium. This approach allows for frequent blood glucose measurements and adjustment of the insulin infusion rate as needed.
By stopping glibenclamide, the risk of hypoglycaemia during surgery is reduced. IV insulin and dextrose with potassium provide a more controlled and predictable method of glycaemic control during the stress of surgery. This approach ensures that the patient’s blood glucose levels remain within a safe range, reducing the risk of complications such as infection, delayed wound healing, and poor surgical outcomes.
In summary, the management of glibenclamide in a patient undergoing major surgery involves discontinuing the medication on the morning of surgery and starting the patient on IV insulin and dextrose with potassium. This approach allows for optimal glycaemic control during the stress of surgery and reduces the risk of complications.
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This question is part of the following fields:
- Endocrinology
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Question 3
Correct
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A 55-year-old male presents at a well man clinic. He has a significant family history of ischaemic heart disease and is a smoker of 10 cigarettes per day. He also consumes approximately 20 units of alcohol per week. On examination, he is found to be obese with a BMI of 32 kg/m2 and has a blood pressure of 152/88 mmHg. His investigations reveal a fasting plasma glucose of 10.5 mmol/L (3.0-6.0), HbA1c of 62 mmol/mol (20-46), and a cholesterol concentration of 5.5 mmol/L (<5.2).
Which intervention would be most effective in reducing his cardiovascular risk?Your Answer: Stop smoking
Explanation:Managing Hypertension and Diabetes for Cardiovascular Risk Reduction
This patient is diagnosed with hypertension and diabetes, as indicated by the elevated fasting plasma glucose. While metformin has been found to reduce cardiovascular (CV) mortality in obese diabetics, ramipril reduces CV risk in hypertensive diabetics, and statins reduce CV mortality, none of these interventions are as effective as quitting smoking in reducing CV risk. The Nurses’ Health Study provides the best evidence for the risk of smoking in women, with past smokers and current smokers having a higher risk compared to non-smokers. In men, there is less definitive evidence, but it is unlikely that many practitioners would consider the other interventions to be more beneficial than smoking cessation. There is currently no evidence that weight loss alone reduces CV mortality, although this may be due to a lack of studies on the topic.
Overall, managing hypertension and diabetes is crucial for reducing the risk of cardiovascular disease. While medication can help, quitting smoking remains the most effective intervention for reducing CV risk. Further research is needed to determine the impact of weight loss on CV mortality.
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This question is part of the following fields:
- Endocrinology
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Question 4
Incorrect
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A 65-year-old individual with diabetes complains of difficulty reading newsprint. Fundoscopy reveals clouding of the lens, making it difficult to visualize the retina.
What is the probable reason for this person's vision impairment?Your Answer: Diabetic maculopathy
Correct Answer: Cataract
Explanation:Premature Cataracts and their Association with Diabetes and Other Conditions
Cataracts can develop prematurely in individuals with certain medical conditions such as diabetes, Cushing’s syndrome, and those who have undergone steroid therapy or experienced trauma. In such cases, it is important to treat the cataracts in order to properly evaluate the back of the eye for signs of diabetic retinopathy. This condition occurs when high blood sugar levels damage the blood vessels in the retina, leading to vision loss. Therefore, it is crucial to monitor the eyes of individuals with these medical conditions to ensure early detection and treatment of any potential complications.
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This question is part of the following fields:
- Endocrinology
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Question 5
Incorrect
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A 63-year-old man presents to his primary care physician with complaints of feeling tired and dizzy upon standing up. His family members are worried because they have noticed a change in his facial appearance. Upon further investigation, the following laboratory results were obtained:
Serum:
Na+ 128 mmol/l (135–145 mmol/l)
K+ 6.1 mmol/l (3.5–5 mmol/l)
Short adrenocorticotropic hormone (ACTH) stimulation test:
Plasma cortisol:
0900 h 150 nmol/l (140–690 nmol/l)
30 min after ACTH: 155 nmol/l
60 min after ACTH: 155 nmol/l
0900 h ACTH: 6 ng/l (normal <50 ng/l)
What condition is consistent with these findings?Your Answer: Adrenal metastases
Correct Answer: Abrupt withdrawal of corticosteroid therapy
Explanation:Causes of Adrenal Hypofunction: Understanding the Biochemistry
Adrenal hypofunction can occur due to various reasons, and understanding the underlying biochemistry can help in identifying the cause. The following are some of the common causes of adrenal hypofunction and their associated biochemical changes:
Abrupt Withdrawal of Corticosteroid Therapy: The most common cause of adrenal hypofunction is the suppression of the pituitary-adrenal axis due to therapeutic corticosteroid therapy. During therapy, patients may present with Cushing’s syndrome, which causes a moon face. However, if therapy is withdrawn abruptly or demand for cortisol increases without a concomitant dosage increase, symptoms and signs of adrenal hypofunction can occur. This results in the loss of Na+ and retention of K+. Prolonged suppression of the adrenals means that output of cortisol cannot increase in response to the ACTH stimulation test until function has recovered. Additionally, patients will classically become hypotensive.
Adrenal Metastases: Adrenal metastases cause adrenal failure through destruction of the gland tissue. So the same biochemistry will occur as in abrupt withdrawal of corticosteroid therapy, but ACTH levels would be expected to be high, owing to lack of negative feedback.
Conn’s Syndrome: In Conn’s syndrome (primary hyperaldosteronism), the high aldosterone levels result in hypernatraemia and hypokalaemia, unlike what is seen in patients with adrenal hypofunction.
Hypopituitarism: This results in secondary adrenal failure, so Na+ is lost and K+ retained.
Cushing’s Disease: Cushing’s disease resulting from overproduction of cortisol results in hypernatraemia and hypokalaemia because cortisol has some mineralocorticoid activity.
In conclusion, understanding the biochemistry of adrenal hypofunction can help in identifying the underlying cause and guiding appropriate treatment.
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This question is part of the following fields:
- Endocrinology
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Question 6
Incorrect
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A 65-year-old man with diabetes and a history of chronic kidney disease visits for his regular check-up. The focus is on his elevated levels of phosphate and parathyroid hormone, despite having normal calcium levels. The doctor decides to prescribe a vitamin D analogue. What would be the most suitable option?
Your Answer: Cholecalciferol (vit D3)
Correct Answer: Alfacalcidol (1-hydroxycholecalciferol)
Explanation:Alfacalcidol as an Effective Treatment for CKD Patients
Alfacalcidol, also known as 1-hydroxycholecalciferol, is a form of vitamin D that is already hydroxylated and does not require activation by the kidney enzyme 1-hydroxylase. This makes it an effective alternative for patients with chronic kidney disease (CKD) as their impaired kidney function can compromise the bioavailability of other forms of vitamin D. Calcitriol is another option for CKD patients.
On the other hand, ascorbic acid, also known as vitamin C, is not involved in the modification of calcium metabolism but rather in the treatment of scurvy, a vitamin C deficiency. Cholecalciferol or vitamin D3, which is obtained from the diet or generated by UV action in the skin, must undergo hydroxylation in the kidney. Vitamin D2, on the other hand, requires activation by the kidney enzyme 1-hydroxylase, which can be impaired in CKD patients.
Lastly, riboflavin or vitamin B2 has no effect on calcium metabolism. In summary, alfacalcidol is an effective treatment option for CKD patients as it does not require activation by the kidney enzyme and can improve the bioavailability of vitamin D.
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This question is part of the following fields:
- Endocrinology
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Question 7
Correct
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A 44-year-old chronic smoker was diagnosed with lung cancer 6 months ago after presenting with weight loss, haemoptysis, and shortness of breath. He returns to the Emergency Department complaining of nausea and lethargy that have been worsening over the past 3 weeks. While waiting to see the doctor, he has a seizure. He has a history of hypertension. The following are the results of his investigations:
Investigations Results Normal value
Sodium (Na+) 120 mmol/l 135–145 mmol/l
Serum osmolality 250 mOsmol/kg 280–290 mOsmol/kg
Urine osmolality 1500 mOsmol/kg 50–1200 mOsmol/kg
Haematocrit 27%
What is the most likely diagnosis?Your Answer: Syndrome of inappropriate antidiuretic secretion (SIADH)
Explanation:Understanding Syndrome of Inappropriate Antidiuretic Secretion (SIADH)
The patient in this scenario is likely experiencing a seizure due to hyponatremia caused by Syndrome of Inappropriate Antidiuretic Secretion (SIADH). SIADH is characterized by hyponatremia, serum hypo-osmolality, urine hyperosmolality, and a decreased hematocrit. The patient’s history of lung cancer is a clue to the underlying cause.
Epilepsy is unlikely as there is no history of seizures mentioned. Central diabetes insipidus presents with hypernatremia, serum hyperosmolality, and urine hypo-osmolality, while nephrogenic diabetes insipidus presents with the same clinical picture. Psychogenic polydipsia is also ruled out as patients with this condition produce hypotonic urine, not hypertonic urine as seen in this patient’s presentation.
Overall, understanding the symptoms and underlying causes of SIADH is crucial in diagnosing and treating patients with this condition.
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This question is part of the following fields:
- Endocrinology
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Question 8
Correct
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A 58-year-old man comes to the clinic with a lump in the anterior of his neck. He denies any symptoms of thyrotoxicosis. His family members have noticed that his voice has become increasingly hoarse over the past few weeks. Fine-needle aspiration indicates papillary carcinoma of the thyroid.
Which of the following statements is true?Your Answer: Thyroidectomy is curative in most cases
Explanation:Myth-busting Facts about Thyroid Cancer
Thyroidectomy is a common treatment for thyroid cancer, and it is curative in most cases. However, there are several misconceptions about this type of cancer that need to be addressed.
Firstly, papillary carcinoma, the most common type of thyroid cancer, is the least aggressive and can be cured with thyroidectomy. Secondly, a hoarse voice is not necessarily an indication of laryngeal involvement, but rather recurrent laryngeal nerve invasion.
Thirdly, while calcitonin levels are raised in medullary carcinoma of the thyroid, this type of cancer is rare and accounts for only a small percentage of cases. Finally, contrary to popular belief, most cases of thyroid cancer are sporadic, and only a small percentage are familial.
It is important to dispel these myths and educate the public about the realities of thyroid cancer to ensure accurate diagnosis and effective treatment.
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This question is part of the following fields:
- Endocrinology
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Question 9
Incorrect
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A 32-year-old woman who has three children presents to the general practice clinic with complaints of feeling tired and overwhelmed. She had previously been prescribed citalopram for about 6 months after the birth of her first child. Her medical history includes the use of depo progesterone for contraception, which she believes is hindering her ability to lose weight. On examination, her BMI is 29 and her blood pressure is 142/72 mmHg. Laboratory tests reveal a slightly elevated TSH level of 4.5 µU/l. Based on these findings, what is the most likely diagnosis?
Your Answer: Hypothyroidism
Correct Answer: Subclinical hypothyroidism
Explanation:Understanding Thyroid Function and Sub-Clinical Hypothyroidism
Thyroid function can be assessed through the levels of thyroid-stimulating hormone (TSH) and free T4 in the blood. Subclinical hypothyroidism is diagnosed when TSH is mildly elevated, while free T4 remains within the normal range. This indicates that the thyroid is working hard to produce even this amount of T4. Treatment with thyroxine replacement is debated and usually reserved for patients with symptoms and thyroid autoantibodies.
Hypothyroidism is diagnosed when free T4 levels fall below the minimum range, while thyrotoxicosis is ruled out when free T4 is not raised and there are no symptoms. Depression may be a plausible diagnosis, but an elevated TSH level suggests otherwise. Sick euthyroid syndrome may occur in critically ill patients and involves abnormal levels of free T4 and T3 despite seemingly normal thyroid function.
Overall, understanding thyroid function and sub-clinical hypothyroidism can help guide appropriate diagnosis and treatment decisions.
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This question is part of the following fields:
- Endocrinology
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Question 10
Incorrect
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A 35-year-old woman with a body mass index of 33 kg/m2 has a fasting blood sugar of 10 mmol/l and 11.7 mmol/l on two separate occasions. Her family history includes diabetes mellitus in her father and maternal uncle. Despite attempting to lose weight through diet and exercise, she has been unsuccessful in achieving a balanced diet. She is open to taking either orlistat or an anorexigenic agent. Further investigation reveals that her blood insulin level tends to be relatively high.
What is the most likely hormonal change to be observed in this patient?Your Answer: Increased cortisol
Correct Answer: Reduced adiponectin
Explanation:Endocrine Factors Predisposing to Type II Diabetes Mellitus
Type II diabetes mellitus is a metabolic disorder characterized by insulin resistance and high blood sugar levels. Several endocrine factors can predispose individuals to this condition. In obese patients with a positive family history of diabetes, adiponectin levels are reduced. Adiponectin is a hormone secreted by adipocytes that plays a role in glucose metabolism. In contrast, leptin levels are increased in these patients and usually correlate with the degree of insulin resistance. Growth hormone levels are increased in acromegaly, which can also predispose individuals to type II diabetes. Phaeochromocytoma, a rare tumor of the adrenal gland, can cause increased epinephrine levels and predispose individuals to diabetes. Similarly, Cushing syndrome, a condition characterized by increased cortisol levels, can also predispose individuals to type II diabetes. Understanding these endocrine factors can help clinicians identify individuals at risk for type II diabetes and implement appropriate preventive measures.
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This question is part of the following fields:
- Endocrinology
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