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Question 1
Correct
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What is the primary role of the kidneys in eliminating waste in a person who is in good health?
Your Answer: Excretion of nitrogenous waste
Explanation:The Kidney’s Role in Excretion of Nitrogenous Waste and Urate
In healthy individuals, the kidney’s primary function is to eliminate toxic nitrogen-containing waste resulting from the breakdown of excess protein. Urea, the primary nitrogenous waste product, is formed through the deamination of excess amino acids. Additionally, the kidney plays a role in the excretion of urate, which comes from the breakdown of nucleic acids from both endogenous and exogenous sources.
However, in diabetic patients with hyperglycemia, glucose is often found in the urine. In normoglycemic individuals, the kidney does not play a role in regulating blood sugar levels. Similarly, the kidney has little involvement in the excretion of fat-soluble substances and lipids.
The liver, on the other hand, plays a significant role in rendering compounds water-soluble to facilitate renal excretion. Substances that remain relatively insoluble are excreted in the bile.
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This question is part of the following fields:
- Nephrology
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Question 2
Incorrect
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A 40-year-old male patient has been referred to the hypertension clinic by his general practitioner due to hypertension that has persisted for the past 18 months. His blood pressure readings have been consistently high, measuring around 210/140 mmHg. During the examination, a large ballotable mass is detected in the right flank. The patient's blood test results reveal elevated levels of renin at 120 pmol/L (normal range: 10-60) and aldosterone at 1215 pmol/L (normal range: 100-800). Additionally, his hemoglobin levels are high at 205 g/L (normal range: 120-170). What is the most likely cause of hypertension in this case?
Your Answer: Phaeochromocytoma
Correct Answer: Renin secretion by a renal cell carcinoma
Explanation:The patient likely has a renal carcinoma, which can cause hypertension through obstruction of renal arteries or secretion of renin. Other symptoms may include polycythaemia, a renal mass, and elevated levels of renin and aldosterone. Renal carcinomas typically present between 40-70 years of age and have a higher incidence in men. Other symptoms may include haematuria, flank pain, weight loss, fever, and night sweats. Rarely, non-reducing varicocele and paraneoplastic syndromes may occur.
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This question is part of the following fields:
- Nephrology
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Question 3
Correct
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As an Emergency department doctor, a 24-year-old man comes to the department with a complaint of blood in his urine that started yesterday. He is typically healthy but recently had a throat infection. Upon conducting a urinalysis, the results are as follows: Haemoglobin +++, Urobilinogen Negative, Bilirubin Negative, Protein +, Glucose Negative, Nitrites Negative, Leucocytes Negative, and Ketones +. What could be the probable reason for these findings?
Your Answer: Nephritic syndrome
Explanation:Nephritic Syndrome and its Underlying Conditions
Nephritic syndrome is a medical condition characterized by blood in the urine, which is likely to be of renal origin. However, it is not a diagnosis in itself and can occur with various underlying renal conditions. The main differential diagnosis for nephritic syndrome is renal stones, which are usually associated with pain.
The underlying conditions that can cause nephritic syndrome include many types of glomerulonephritis, haemolytic uraemic syndrome, Henoch-Schönlein purpura, Goodpasture syndrome, infective endocarditis, systemic lupus erythematosus (SLE) or lupus nephritis, vasculitis, and viral diseases such as hepatitis B or C, EBV, measles, and mumps.
When diagnosing nephritic syndrome, urinalysis is crucial as it will show abundant haemoglobin. However, it is important to note that this can sometimes lead to false positives for bilirubin and urobilinogen, which are related substances. the underlying conditions that can cause nephritic syndrome is essential for proper diagnosis and treatment.
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This question is part of the following fields:
- Nephrology
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Question 4
Correct
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Which patient has a creatinine level indicating CKD3?
Patient A:
Adjusted calcium - 2.3 mmol/L
Phosphate - 0.9 mmol/L
PTH - 8.09 pmol/L
Urea - 7.8 mmol/L
Creatinine - 145 μmol/L
Albumin - 36 g/L
Patient B:
Adjusted calcium - 2.9 mmol/L
Phosphate - 2.0 mmol/L
PTH - 4.2 pmol/L
Urea - 50 mmol/L
Creatinine - 280 μmol/L
Albumin - 38 g/L
Patient C:
Adjusted calcium - 2.0 mmol/L
Phosphate - 2.8 mmol/L
PTH - 12.53 pmol/L
Urea - 32.8 mmol/L
Creatinine - 540 μmol/L
Albumin - 28 g/L
Patient D:
Adjusted calcium - 2.5 mmol/L
Phosphate - 1.6 mmol/L
PTH - 2.05 pmol/L
Urea - 32.8 mmol/L
Creatinine - 367 μmol/L
Albumin - 40 g/L
Patient E:
Adjusted calcium - 2.2 mmol/L
Phosphate - 0.7 mmol/L
PTH - 5.88 pmol/L
Urea - 4.6 mmol/L
Creatinine - 81 μmol/L
Albumin - 18 g/LYour Answer: Patient A
Explanation:Renal Impairment and Calcium Homeostasis
Although interpreting creatinine levels can be challenging without information about body habitus and muscle mass, Patient A likely has CKD3 based on their creatinine level of 145. It is important to have a general of the severity of renal impairment based on creatinine levels. Patients with an eGFR of 30-59 ml/min/1.73m2 are classified as having CKD3. This classification applies to men and women between the ages of 20 and 80 years old.
Patients B, C, and D have more advanced renal disease, and depending on the clinical context, patients B and D may have acute renal failure. Patient E, on the other hand, does not have any renal impairment.
Patients with kidney disease often experience multiple abnormalities in calcium homeostasis. At the CKD3 stage, most patients have normal plasma concentrations of calcium and phosphate. However, as CKD3 progresses towards CKD 4, more subtle abnormalities may arise, such as a slight increase in PTH due to reduced hydroxylation of vitamin D by the kidney enzyme 1-alpha hydroxylase.
Although Patient A has suboptimal levels of vitamin D, this is not uncommon. Risk factors for vitamin D insufficiency include old age, immobility, institutionalization, and darker skin color.
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This question is part of the following fields:
- Nephrology
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Question 5
Incorrect
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Which patient has an elevated PTH level that is indicative of primary hyperparathyroidism?
Patient A:
Adjusted calcium - 2.3 mmol/L
Phosphate - 0.9 mmol/L
PTH - 8.09 pmol/L
Urea - 7.8 mmol/L
Creatinine - 132 μmol/L
Albumin - 36 g/L
Patient B:
Adjusted calcium - 2.9 mmol/L
Phosphate - 0.5 mmol/L
PTH - 7.2 pmol/L
Urea - 5 mmol/L
Creatinine - 140 μmol/L
Albumin - 38 g/L
Patient C:
Adjusted calcium - 2.0 mmol/L
Phosphate - 2.8 mmol/L
PTH - 12.53 pmol/L
Urea - 32.8 mmol/L
Creatinine - 540 μmol/L
Albumin - 28 g/L
Patient D:
Adjusted calcium - 2.5 mmol/L
Phosphate - 1.6 mmol/L
PTH - 2.05 pmol/L
Urea - 32.8 mmol/L
Creatinine - 190 μmol/L
Albumin - 40 g/L
Patient E:
Adjusted calcium - 2.2 mmol/L
Phosphate - 0.7 mmol/L
PTH - 5.88 pmol/L
Urea - 4.6 mmol/L
Creatinine - 81 μmol/L
Albumin - 18 g/LYour Answer: Patient A
Correct Answer: Patient B
Explanation:Primary Hyperparathyroidism and its Complications
Primary hyperparathyroidism is a condition where the parathyroid glands produce too much parathyroid hormone (PTH), leading to elevated calcium levels and low serum phosphate. This condition can go undiagnosed for years, with an incidental finding of elevated calcium often being the first clue. However, complications can arise from longstanding primary hyperparathyroidism, including osteoporosis, renal calculi, and renal calcification.
Osteoporosis occurs due to increased bone resorption under the influence of high levels of PTH. Renal calculi are also a common complication, as high levels of phosphate excretion and calcium availability can lead to the development of calcium phosphate renal stones. Additionally, calcium deposition in the renal parenchyma can cause renal impairment, which can develop gradually over time.
Patients with longstanding primary hyperparathyroidism are at risk of impaired renal function, which is less common in patients with chronic kidney disease of other causes. While both conditions may have elevated PTH levels, hypocalcaemia is more common in chronic kidney disease due to impaired hydroxylation of vitamin D. the complications of primary hyperparathyroidism is crucial for early diagnosis and management of this condition.
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This question is part of the following fields:
- Nephrology
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Question 6
Incorrect
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A patient in his 60s visits his GP clinic complaining of general malaise, severe itch, and breathlessness that have been progressively worsening for several months. Upon conducting blood tests, the following results were obtained: adjusted calcium of 2.0 mmol/L (normal range: 2.2-2.4), phosphate of 2.8 mmol/L (normal range: 0.7-1.0), PTH of 12.53 pmol/L (normal range: 1.05-6.83), urea of 32.8 mmol/L (normal range: 2.5-7.8), creatinine of 540 µmol/L (normal range: 60-120), 25 OH Vit D of 32 nmol/L (optimal level >75), and eGFR of 8 ml/min/1.73m2. What is the most effective treatment for this patient?
Your Answer: Vitamin D supplementation
Correct Answer: Dialysis
Explanation:Dialysis as the Best Option for CKD 5 Patients with Severe Symptoms
Patients with CKD 5 and an eGFR less than 15 ml/min/1.73m2 are likely to benefit most from dialysis, especially when they experience severe symptoms. Itch, for instance, is a common symptom of uraemia that can be very difficult to treat. On the other hand, breathlessness is often due to fluid buildup in the peritoneum and pleurae, which can be addressed by dialysis. While patients with CKD 5 are regularly reviewed by a renal department, the decision to start dialysis is usually made in a non-emergency setting.
In cases where patients experience side effects that are difficult to treat without dialysis, supplementing calcium or vitamin D may not significantly change their current condition. Moreover, supplementing phosphate would be inappropriate as most patients with CKD 5 already have high serum phosphate levels and should be on a low phosphate diet. Therefore, dialysis remains the best option for CKD 5 patients with severe symptoms, as it can effectively address the underlying causes of their discomfort.
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This question is part of the following fields:
- Nephrology
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Question 7
Correct
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A 45-year-old man presents to the Emergency department with a general feeling of being unwell. He has no history of chronic disease or renal impairment. Upon blood testing, his results show elevated levels of creatinine, urea, potassium, creatine kinase, and phosphate, as well as a slightly low sodium level and an elevated CRP level. What could be the possible cause of his renal impairment?
Your Answer: Rhabdomyolysis
Explanation:Rhabdomyolysis and Myoglobinuria
Rhabdomyolysis is a condition that results from muscle damage and lysis of muscle cells. This leads to the release of cellular contents such as potassium, myoglobin, CK, and phosphate into the bloodstream. Excessive myoglobin release overwhelms the ability of haptoglobin to clear it, leading to its filtration by the glomerulus and entry into the urine. This causes damage to tubular cells in the renal tubule, resulting in free radical release and cast formation.
There are several causes of rhabdomyolysis and myoglobinuria, including trauma, compartment syndrome, crush injury, ischaemia, severe electrolyte disturbances, bacterial and viral infections, inherited metabolic disorders such as McArdle’s disease, and drugs such as barbiturates and statins (although this is rare).
In summary, rhabdomyolysis and myoglobinuria are serious conditions that can result from a variety of causes. the underlying mechanisms and potential triggers can help with early diagnosis and treatment, which is crucial for preventing further complications.
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This question is part of the following fields:
- Nephrology
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Question 8
Correct
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As a locum GP, you come across a 40-year-old woman who is experiencing chills, pelvic discomfort, and painful urination. This patient has no history of diabetes. What are the possible urinalysis results that you might expect in this scenario?
A) Haemoglobin: Negative, Urobilinogen: Negative, Bilirubin: Negative, Protein: +, Glucose: +++, Nitrites: Negative, Leucocytes: +, Ketones: Negative
B) Haemoglobin: Negative, Urobilinogen: Negative, Bilirubin: Negative, Protein: Negative, Glucose: +, Nitrites: +++, Leucocytes: ++, Ketones: +++
C) Haemoglobin: +++, Urobilinogen: Negative, Bilirubin: Negative, Protein: Negative, Glucose: Negative, Nitrites: +++, Leucocytes: +++, Ketones: Negative
D) Haemoglobin: Negative, Urobilinogen: Negative, Bilirubin: Negative, Protein: Negative, Glucose: Negative, Nitrites: ++++, Leucocytes: Negative, Ketones: +++
E) Haemoglobin: Negative, Urobilinogen: +, Bilirubin: +, Protein: Negative, Glucose: Negative, Nitrites: +++, Leucocytes: Negative, Ketones: Negative
It is important to note that the urinalysis results may vary depending on the individual patient's condition and medical history. As a healthcare professional, it is crucial to conduct a thorough examination and analysis to determine the appropriate diagnosis and treatment plan for the patient.Your Answer: C
Explanation:Urinalysis Findings in Urinary Tract Infection
Urinary tract infection (UTI) is a common condition that can be diagnosed through urinalysis. Nitrites and leucocytes are typically present in large amounts in the urine of patients with UTI. Blood may also be present due to inflammation in the bladder or contamination from menstrual bleeding. In some cases, a small amount of glucose may be detected as the body responds to infection by releasing cortisol and adrenaline, which can increase blood glucose levels. However, the presence of protein on urinalysis is usually based on measurement of albumin only, and bacterial proteins are not typically detected using this method. Overall, urinalysis can provide valuable information for diagnosing and managing UTI.
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This question is part of the following fields:
- Nephrology
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Question 9
Incorrect
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A 65-year-old woman presents to her GP with a complaint of general malaise. Upon conducting blood tests, the following results were obtained:
Adjusted calcium: 2.3 mmol/L (2.2-2.4)
Phosphate: 0.9 mmol/L (0.7-1.0)
PTH: 8.09 pmol/L (1.05-6.83)
Urea: 7.8 mmol/L (2.5-7.8)
Creatinine: 145 μmol/L (60-120)
25 OH Vit D: 48 nmol/L (optimal >75)
What is the most likely diagnosis?Your Answer: Vitamin D deficiency
Correct Answer: Chronic kidney disease
Explanation:Creatinine and Calcium Homeostasis in CKD 3 Patients
In patients with CKD 3, elevated creatinine levels indicate a decline in kidney function. However, interpreting creatinine levels can be challenging without considering factors such as body habitus and muscle mass. To determine the severity of CKD 3, an eGFR calculation can be performed, which typically results in a value of 30-59 ml/min/1.73m2.
Patients with CKD 3 may experience multiple abnormalities in calcium homeostasis. While plasma concentrations of calcium and phosphate are usually normal at this stage, subtle changes may occur as CKD3 progresses towards CKD 4. For example, reduced hydroxylation of vitamin D by the kidney enzyme 1-alpha hydroxylase can lead to a slight increase in PTH levels.
Vitamin D insufficiency is common in CKD3 patients and can be caused by various risk factors such as old age, immobility, institutionalization, and darker skin color. While suboptimal levels of vitamin D may contribute to calcium homeostasis abnormalities, it is not the only factor to consider in CKD3 management.
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This question is part of the following fields:
- Nephrology
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Question 10
Incorrect
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A patient in their late 60s with end stage renal disease on haemodialysis is admitted with sudden onset of wheezing and shortness of breath. They have swollen ankles and a raised JVP of 7 cm, with a blood pressure of 110/50 mmHg. Upon chest examination, there are widespread coarse crackles. A chest radiograph reveals complete opacification of both lung fields and blunting of the left costophrenic angle. The patient had their usual haemodialysis session the previous night. What could be the potential cause of this acute presentation?
Your Answer: Excess fluid intake
Correct Answer: Myocardial infarction
Explanation:Cardiovascular Risk in Haemodialysis Patients
Haemodialysis patients are at a significantly higher risk of developing cardiovascular disease. Therefore, any sudden deterioration in their condition is a cause for concern. In the case of a previously stable dialysis patient presenting with low blood pressure, excess fluid intake is unlikely to be the cause. Instead, a cardiac event is the most likely explanation.
It is improbable that inadequate haemodialysis is the cause of the patient’s symptoms, as they had a session less than 24 hours ago. Furthermore, if this were the case, the patient would likely have high blood pressure due to fluid accumulation.
While patients on dialysis are more susceptible to infections, the presentation is consistent with acute pulmonary oedema. This condition occurs when fluid accumulates in the lungs, making it difficult to breathe. Therefore, it is essential to monitor haemodialysis patients closely for any signs of cardiovascular disease and promptly address any acute events that may arise.
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This question is part of the following fields:
- Nephrology
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Question 11
Correct
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A 30-year-old man with end stage renal failure due to IgA nephropathy underwent a kidney transplant from a deceased brainstem donor and experienced successful primary graft function. After being discharged eight days post-surgery, his creatinine levels stabilized at 85 umol/l with regular clinic visits. However, at seven weeks post-transplant, his creatinine levels increased to 190 umol/l despite being asymptomatic. As a result, he was admitted for further evaluation. What would be your initial course of action?
Your Answer: Request a renal ultrasound scan
Explanation:The patient’s sudden rise in creatinine after stent removal suggests obstruction leading to hydronephrosis. This is the most likely diagnosis, but other possibilities include acute rejection, calcineurin toxicity, infection, or surgical complications. A renal ultrasound is needed to confirm the diagnosis and rule out other issues before a renal biopsy can be considered. Donor specific antibodies may also be tested, but a biopsy is still necessary for confirmation and treatment.
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This question is part of the following fields:
- Nephrology
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Question 12
Correct
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A 40-year-old man has just finished a round of chemotherapy for leukemia. During a routine check-up, he is discovered to have proteinuria with a level of 1000 mg/24 hours. Upon examination, there are no red cell casts present in his urine. What could be the probable reason for his proteinuria?
Your Answer: Tubular proteinuria
Explanation:Causes of Tubular Proteinuria
Tubular proteinuria is a condition where proteins are excreted in the urine due to damage to the renal tubules. One common cause of this condition is chemotherapy, particularly ifosphamide and platinum-based agents. Other causes include Fanconi’s syndrome, heavy metal poisoning, tubulointerstitial disease, and the use of certain drugs such as gentamicin. Diabetes, infections, and transplant rejection can also lead to tubular proteinuria.
In summary, there are various factors that can cause tubular proteinuria, and it is important to identify the underlying cause in order to provide appropriate treatment. Patients who have undergone chemotherapy should be monitored for signs of renal tubular damage, and any medication that may contribute to the condition should be reviewed. Early detection and management of tubular proteinuria can help prevent further kidney damage and improve patient outcomes.
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This question is part of the following fields:
- Nephrology
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Question 13
Incorrect
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A 47-year-old woman visits the renal clinic after six weeks of a triumphant renal transplant. She has some inquiries about her immunosuppression for the consultant. The doctor clarifies that the typical regimen for renal transplant patients involves the initial utilization of an induction agent, followed by a combination of a calcineurin inhibitor, antimetabolite, and steroids. This combination is intended to prevent rejection of the transplanted kidney. What is the name of the anti-lymphocyte monoclonal antibody used as an induction agent?
Your Answer: Azathioprine
Correct Answer: Alemtuzumab
Explanation:Immunosuppressive Drugs and Their Mechanisms of Action
Alemtuzumab is a monoclonal antibody that targets CD52 and depletes mature lymphocytes, but not stem cells. It has been found to be more effective than traditional therapy in preparing patients for renal transplantation.
Tacrolimus is a calcineurin inhibitor that reduces the activation of NFAT, a transcription factor that promotes the production of IL-2, the primary cytokine that drives T cell proliferation.
Both azathioprine and mycophenolate mofetil are antimetabolites that disrupt DNA synthesis. Mycophenolate indirectly inhibits inosine monophosphate dehydrogenase, which prevents purine synthesis. Azathioprine is a pro-drug that is metabolized into 6-mercaptopurine, which is inserted into the DNA sequence instead of a purine, triggering apoptosis.
Sirolimus is an mTOR inhibitor that acts downstream of IL-2 signaling to promote T cell proliferation and survival.
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This question is part of the following fields:
- Nephrology
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Question 14
Incorrect
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A patient who had her PD catheter inserted into her abdomen complains that the first bag of the morning is often difficult to instil, and she cannot remove any fluid after the four hour dwell. Later in the day, this is better, and she can usually remove the fluid from the morning and instil the next bag and remove it after the dwell. What is the most probable reason for this issue?
Your Answer: Absorption of fluid
Correct Answer: Catheter kinking
Explanation:Common Issues with Peritoneal Dialysis Catheters
Kinking of the catheter is a common issue that occurs shortly after insertion. This can cause problems with both fluid inflow and outflow, and symptoms may vary depending on the patient’s position. Catheter malposition is another early issue that can be painful and uncomfortable for the patient. If absorption of PD fluid is occurring, patients may experience signs of fluid overload, such as swollen ankles, indicating a need for a higher concentration of osmotic agent in the fluid. Constipation is a consistent cause of outflow obstruction, while leakage can be noticed as fluid coming from the exit site or swelling around the site as fluid leaks into subcutaneous tissues. It is important to monitor for these common issues and address them promptly to ensure the success of peritoneal dialysis treatment.
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This question is part of the following fields:
- Nephrology
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Question 15
Incorrect
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A 49-year-old man underwent a kidney transplant two years ago due to end stage renal failure caused by ANCA associated vasculitis. He recently visited the clinic with complaints of sweating palms, weight loss, insomnia, and tremors. Upon conducting thyroid function tests, an undetectable TSH and a free T4 of 25 mg/dL (NR 4.5-11.5) were observed. The patient was diagnosed with Graves' disease after testing positive for thyroid stimulating hormone receptor (TSH-R) antibodies. Which medication could have potentially contributed to this condition?
Your Answer: Rituximab
Correct Answer: Alemtuzumab
Explanation:Alemtuzumab is a monoclonal antibody used to treat autoimmune diseases and can cause lymphocyte depletion. However, it is associated with autoimmunity after treatment, particularly autoimmune thyroid disease. Regular thyroid function screening is important for patients who have received alemtuzumab. Other monoclonal antibodies, such as adalimumab, basiliximab, rituximab, and ciclosporin, are not known to be associated with autoimmunity.
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This question is part of the following fields:
- Nephrology
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Question 16
Correct
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As an Emergency department doctor, a 50-year-old man presents with intense left flank pain that extends to his groin. He reports that the pain began yesterday. Upon conducting a urinalysis, the following results were obtained:
- Haemoglobin +++
- Urobilinogen Negative
- Bilirubin Negative
- Protein Negative
- Glucose Negative
- Nitrites Negative
- Leucocytes Negative
- Ketones +
What could be the possible cause of these findings?Your Answer: Renal calculus
Explanation:Renal Calculi: Causes and Symptoms
Renal calculi, commonly known as kidney stones, can be caused by various factors such as reduced urine output, changes in medication, and diet. These factors can lead to the formation of stones in the urinary tract, which can cause inflammation and damage to the lining of the urinary tract. Patients with renal calculi may experience symptoms such as blood in their urine due to the damage caused by the stones. Additionally, ketones may be present in the urine, indicating reduced oral intake due to severe pain.
In summary, renal calculi can be caused by various factors and can lead to symptoms such as blood in the urine and reduced oral intake. It is important for patients to seek medical attention if they suspect they may have renal calculi to receive proper diagnosis and treatment.
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This question is part of the following fields:
- Nephrology
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Question 17
Correct
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A 45-year-old woman who suffers from chronic back pain and takes regular doses of paracetamol and ibuprofen has been diagnosed with proteinuria at a level of 900 mg/24 hours. Upon further examination, it was discovered that her urine contains small proteins with minimal amounts of albumin. What could be the probable reason for her proteinuria?
Your Answer: Tubular proteinuria
Explanation:Proteinuria and its Possible Causes
Proteinuria is the presence of an abnormal amount of protein in the urine, which may indicate an underlying medical condition. While a small amount of protein is normally present in urine, a high level of protein in urine is a sign of a pathological cause. The possible origins of protein in urine are shown in the diagram.
In cases where there is tubulointerstitial damage, chronic use of analgesics and/or anti-inflammatory drugs, particularly NSAIDs, is the likely cause. This type of damage impairs the reabsorption of filtered low molecular weight proteins, leading to tubular proteinuria. This type of proteinuria typically results in the non-selective loss of relatively small proteins in the urine. the possible causes of proteinuria can help in the diagnosis and treatment of underlying medical conditions.
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This question is part of the following fields:
- Nephrology
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Question 18
Incorrect
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What distinguishes haemodialysis from haemofiltration as methods of renal replacement therapy?
Your Answer: Haemofiltration removes solutes by diffusion
Correct Answer: Haemodialysis removes solutes by osmosis
Explanation:Haemodialysis vs Haemofiltration
Haemodialysis and haemofiltration are two methods of renal replacement therapy used to treat patients with kidney failure. Haemodialysis involves removing blood at a high flow rate and passing it through a dialyser with dialysis fluid running in the opposite direction. This creates a constant diffusion gradient, allowing solutes to diffuse across and be removed from the blood. Haemodialysis is administered intermittently and is highly effective at solute removal due to the high flow rates and constant diffusion gradient.
On the other hand, haemofiltration is less efficient and requires high volumes to achieve the same degree of solute clearance. It works by passing the blood at low flow rates but high pressures through the dialyser without dialysate fluid. Instead, a transmembrane pressure gradient is created, allowing fluid to be squeezed out. However, it is less efficient at solute clearance. Haemofiltration requires replacement fluid to be administered to avoid hypovolaemia due to the large volumes filtered.
In summary, haemodialysis and haemofiltration are two different methods of renal replacement therapy. Haemodialysis is highly effective at solute removal due to the high flow rates and constant diffusion gradient, while haemofiltration is more efficient at clearing fluid but less efficient at solute clearance. Both methods have their advantages and disadvantages, and the choice of therapy depends on the patient’s individual needs and medical condition.
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This question is part of the following fields:
- Nephrology
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Question 19
Correct
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A patient is admitted from clinic eight weeks following a renal transplant. Despite feeling well, his creatinine has increased from a baseline of 120 umol/l to 170 umol/l in just one week. After a normal ultrasound scan, he undergoes a transplant biopsy which reveals linear C4d staining along the peritubular capillaries and widespread glomerulitis with neutrophil and macrophage infiltration. What is the probable diagnosis?
Your Answer: Antibody mediated rejection
Explanation:C4d Staining as a Marker for Antibody Mediated Rejection
Linear staining for C4d is a useful tool in detecting complement activation via the classical pathway, which is mediated by antibodies. C4d is a breakdown component of C4 that binds to the basement membrane, indicating antibody mediated complement activation. In cases where antibody mediated rejection is suspected, C4d staining is highly sensitive for acute rejection. A serum sample for donor specific antibodies should be sent off urgently to confirm the diagnosis.
Chronic background antibody mediated rejection can also show C4d staining, but the presence of C4d along the peritubular capillaries is a strong indicator of acute antibody mediated rejection. This, along with the presence of glomerulitis and acute inflammatory infiltrate, supports the diagnosis of acute antibody mediated rejection.
Other conditions, such as acute tubular necrosis, bacterial pyelonephritis, acute viral infection, and acute cellular rejection, can be ruled out based on their distinct features. Acute tubular necrosis shows flattening of the tubular epithelium with sloughing of the cells, while bacterial pyelonephritis tends to cause a tubulointerstitial nephritis. Acute viral infection and acute cellular rejection both show lymphocytic infiltration rather than granulocyte infiltration, but can be distinguished through blood viral PCR and virus specific stains.
In summary, C4d staining is a valuable tool in detecting antibody mediated complement activation and can aid in the diagnosis of acute antibody mediated rejection. Other conditions can be ruled out based on their distinct features, and further testing may be necessary to confirm the diagnosis.
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This question is part of the following fields:
- Nephrology
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Question 20
Correct
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As a locum GP, you have been presented with blood results for five patients you have never met before. The results are as follows:
Patient A: Adjusted calcium - 2.8 mmol/L, Phosphate - 0.9 mmol/L, PTH - 8.09 pmol/L, Urea - 7.8 mmol/L, Creatinine - 132 μmol/L, Albumin - 36 g/L.
Patient B: Adjusted calcium - 2.9 mmol/L, Phosphate - 0.5 mmol/L, PTH - 7.2 pmol/L, Urea - 5 mmol/L, Creatinine - 140 μmol/L, Albumin - 38 g/L.
Patient C: Adjusted calcium - 2.0 mmol/L, Phosphate - 2.8 mmol/L, PTH - 12.53 pmol/L, Urea - 32.8 mmol/L, Creatinine - 540 μmol/L, Albumin - 28 g/L.
Patient D: Adjusted calcium - 2.5 mmol/L, Phosphate - 1.6 mmol/L, PTH - 2.05 pmol/L, Urea - 32.8 mmol/L, Creatinine - 190 μmol/L, Albumin - 40 g/L.
Patient E: Adjusted calcium - 2.2 mmol/L, Phosphate - 0.7 mmol/L, PTH - 5.88 pmol/L, Urea - 4.6 mmol/L, Creatinine - 81 μmol/L, Albumin - 18 g/L.
Your task is to identify which patient is likely to have acute kidney injury (AKI). Take your time to carefully review the results and make an informed decision.Your Answer: Patient D
Explanation:Biochemical Indicators of Dehydration and Kidney Function
The biochemical indicators in a patient’s blood can provide insight into their kidney function and hydration status. In cases of dehydration leading to acute renal failure (ARF) or acute kidney injury (AKI), there may be slight elevations in calcium and phosphate levels, indicating some haemoconcentration. However, the urea level is typically significantly higher compared to a more modest increase in creatinine. A urea level of 32 mmol/L is commonly seen in AKI, whereas in stable chronic kidney disease (CKD), it would typically be associated with a much higher creatinine level.
CKD often presents with multiple biochemical abnormalities that are not typically seen in AKI. These include hypocalcaemia, increased levels of parathyroid hormone (PTH) as a compensatory response to hypocalcaemia, and anemia due to erythropoietin and iron deficiency. Patients with primary hyperparathyroidism, such as Patient A and B, may have inappropriately high PTH levels with mild hypercalcaemia. Patient C, on the other hand, has CKD with secondary hyperparathyroidism. Finally, Patient E has normal blood indicators, suggesting no significant kidney or hydration issues.
Overall, the biochemical indicators of dehydration and kidney function can aid in diagnosing and managing ARF, AKI, and CKD.
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This question is part of the following fields:
- Nephrology
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Question 21
Incorrect
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A patient who has been on peritoneal dialysis for six years contacts the clinic with concerns. The patient reports infusing 1.5 litres of fluid into their abdomen but only being able to remove 1 litre at the end of their dwell. However, the patient is not experiencing any symptoms and does not have ankle oedema.
What could be causing this issue?Your Answer: Leak from catheter site
Correct Answer: Constipation
Explanation:Common Causes of Catheter Outflow Obstruction in Peritoneal Dialysis Patients
Constipation is a frequent cause of catheter outflow obstruction in patients who have been on peritoneal dialysis for a while. This can happen at any point and is due to the low-fiber renal diet that is recommended to avoid potassium and phosphate excess. The design of PD fluid with osmotic agents means that fluid should not be absorbed in significant quantities. If absorption is occurring, patients will show signs of fluid overload, such as swollen ankles, indicating that a higher concentration of osmotic agent is required. Leakage is noticeable as either fluid coming from the exit site or swelling around the exit site as fluid leaks into subcutaneous tissues.
Catheter malposition is often painful and tends to occur early on after insertion, not years after catheter placement. Kinking of the catheter also usually occurs early after insertion and may vary with position. It tends to cause problems with fluid inflow as well as outflow. By these common causes of catheter outflow obstruction, healthcare providers can better diagnose and treat peritoneal dialysis patients.
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This question is part of the following fields:
- Nephrology
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Question 22
Incorrect
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A patient admitted for treatment of PD peritonitis has had their cloudy PD fluid sent for culture and has been started on empirical antibiotics while awaiting results. What is the most probable pathogen responsible for the infection?
Your Answer: E. coli
Correct Answer: Coagulase negative staph
Explanation:Causes of PD Peritonitis
PD peritonitis is a common complication of peritoneal dialysis, with 50% of episodes caused by Gram positive organisms. The most frequent culprit is coagulase negative staph, which is often due to contamination from skin flora. While Staph. aureus is becoming more prevalent, it is still less common than coagulase negative staph. Gram negative organisms, such as E. coli, are responsible for only 15% of PD peritonitis cases. Pseudomonas is rare and challenging to treat. Fungal organisms cause peritonitis in less than 2% of patients. Overall, the causes of PD peritonitis is crucial for effective management and prevention of this complication.
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This question is part of the following fields:
- Nephrology
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Question 23
Incorrect
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In the treatment of autoimmunity and to prevent rejection following solid organ transplantation, various immunosuppressant drugs are used, each with its own mechanism of action and specific side effects. However, all of them carry the risk of increased susceptibility to infection and malignancy. At what age is new onset of diabetes after transplantation (NODAT) commonly associated with medication?
Your Answer: Azathioprine
Correct Answer: Tacrolimus
Explanation:New Onset Diabetes After Transplantation (NODAT)
New onset diabetes after transplantation (NODAT) is a condition that is becoming increasingly common among transplant recipients. It is estimated that between 5-20% of recipients develop NODAT within the first year after transplantation, and up to 30% in the longer term. The use of prednisolone is often associated with NODAT, especially in patients who had impaired glucose tolerance before the transplant. However, calcineurin inhibitors such as ciclosporin and tacrolimus are also known to increase the risk of NODAT. The risk of NODAT with ciclosporin is around 5%, while it can be as high as 20% with tacrolimus. Sirolimus, another immunosuppressive drug, is also believed to be diabetogenic, with similar rates to ciclosporin. It is worth noting that cyclophosphamide is not used in transplantation immunotherapy, while azathioprine and mycophenolate mofetil are not associated with NODAT.
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This question is part of the following fields:
- Nephrology
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Question 24
Incorrect
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A patient who has been on peritoneal dialysis for three weeks has reported that despite instilling a full 2 litre bag of fluid, he only gets 1.9 litres back. Additionally, he has noticed swelling in his abdomen and tenderness upon palpation. What could be the probable cause of these issues?
Your Answer: Absorption of fluid
Correct Answer: Leak from catheter site
Explanation:Common Issues with Peritoneal Dialysis Catheters
Leakage is a common issue with peritoneal dialysis catheters, especially in patients who have had previous abdominal surgery. It can be noticed as fluid leaking around the exit site or causing mild swelling. Reducing fluid volumes may help, but catheter repair or replacement may be necessary. If patients show signs of fluid overload, a higher concentration of osmotic agent may be required. Catheter malposition is often painful and occurs early after insertion. Constipation is the most common cause of outflow obstruction, which tends to be consistent or worsening. Kinking of the catheter also occurs early after insertion and can cause problems with fluid inflow and outflow. Proper management of these issues is important for the success of peritoneal dialysis treatment.
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This question is part of the following fields:
- Nephrology
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Question 25
Correct
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A 49-year-old man visits his GP complaining of a weak and painful right leg that has been bothering him for a week. Upon examination, the GP observes a foot drop on the right side with 3/5 power for dorsiflexion, as well as a bilateral sensory peripheral neuropathy that is worse on the right side. The GP also notices weakness of wrist extension on the left, which the patient had not previously mentioned. The patient's chest, heart, and abdomen appear normal, and his urine dipstick is clear. His medical history is significant only for asthma, which was diagnosed four years ago.
The patient's FBC reveals a white cell count of 6.7 x109/l (normal range: 4 - 11), with neutrophils at 4.2 x109/l (normal range: 1.5 - 7), lymphocytes at 2.3 x109/l (normal range: 1.5 - 4), and eosinophils at 2.2 x109/l (normal range: 0.04 - 0.4). His ESR is 68mm/hr (normal range: 0 - 15), and his biochemistry is normal except for a raised CRP at 52 mg/l. Nerve conduction studies show reduced amplitude sensory signals bilaterally and patchy axonal degeneration on the right side with reduced motor amplitude.
What is the most likely diagnosis?Your Answer: eosinophilic granulomatosis with polyangiitis (EGPA)
Explanation:Differential Diagnosis for Mononeuritis Multiplex
Mononeuritis multiplex is a condition characterized by the inflammation of multiple nerves, resulting in both sensory and motor symptoms. While several conditions can cause this, eGPA is the most likely diagnosis for this patient due to his history of adult onset asthma and significantly raised eosinophil count. The painful loss of function, raised inflammatory markers, and reduced amplitude nerve conduction studies also suggest an inflammatory cause of his neuropathy.
While amyloidosis is a possibility, the patient has no history of a disorder that might predispose to secondary amyloid, and no signs of systemic amyloidosis. B12 deficiency and diabetes mellitus are unlikely causes of mononeuritis multiplex, as they do not typically present with this pattern of neuropathy. Lyme disease is also unlikely, as the patient has no rash or arthritis and no history of tick bite.
In summary, while several conditions can cause mononeuritis multiplex, the patient’s history and test results suggest eGPA as the most likely diagnosis. It is important to consider other possibilities, such as amyloidosis, but the inflammatory nature of the patient’s symptoms points towards eGPA as the primary cause.
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This question is part of the following fields:
- Nephrology
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Question 26
Correct
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A 30-year-old woman who leads an active lifestyle visits her doctor for a routine work-related health check-up. During the check-up, her urinalysis shows a positive result for protein (+) and a 24-hour urine collection is ordered. The results reveal a urine protein level of 25 mg/24 hours. What recommendations should be provided to the patient?
Your Answer: This result is within normal limits
Explanation:Proteinuria and its Significance in Patient Assessment
Proteinuria is a condition where protein is present in the urine, which can be an indicator of kidney disease or other underlying health issues. When assessing a patient with suspected proteinuria, it is important to consider their age, activity levels, and the presence of diseases such as diabetes.
Urine albumin levels of 30-300 mg/24 hours are considered microalbuminuria, which is a marker of cardiovascular risk and can predict chronic kidney disease, especially in patients with diabetes. This is usually estimated using the albumin-creatinine ratio (ACR), where an ACR of >3.5 mg/mmol in women or >2.5 mg/mmol in men is considered abnormal. Albuminuria is defined as >300 mg/24 hours or an ACR of >30 mg/mmol.
In some patients, particularly young adults, low-level proteinuria (140 mg – 1 g /24 hours) can be normal and may be caused by factors such as exercise, postural changes, or a high protein diet. However, urine microscopy should be done to exclude casts or cells. Proteinuria levels of 1-2 g/24 hours are more concerning and can be a sign of developing kidney disease such as glomerulonephritis.
If proteinuria levels exceed 3 g/24 hours, it is diagnostic of nephrotic syndrome and requires admission to the hospital for further investigation and management. Some authorities use a cut-off of 3.5 g/24 hours in this case. the significance of proteinuria levels is crucial in patient assessment and can aid in the early detection and management of kidney disease and other underlying health issues.
Overall, proteinuria levels should be carefully monitored and evaluated in the context of the patient’s overall health and medical history.
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This question is part of the following fields:
- Nephrology
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Question 27
Correct
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A 50-year-old woman undergoing haemodialysis for end stage renal failure caused by vesico-ureteric reflux is experiencing a dry, flaky skin and an itchy rash. What is the probable complication of end stage renal failure responsible for these symptoms?
Your Answer: Hyperphosphataemia
Explanation:Hyperphosphataemia and Itching in End Stage Renal Failure Patients
Patients with end stage renal failure often experience hyperphosphataemia, which is caused by the loss of renal control over calcium/phosphate balance. This occurs because the kidneys are no longer able to excrete phosphate and produce activated vitamin D. As a result, calcium levels decrease, leading to secondary hyperparathyroidism, which maintains calcium levels but at the expense of raised phosphate levels. Hyperphosphataemia can cause itching and dermatitis, making it important to restrict dietary phosphate intake and use phosphate binders taken with meals to prevent phosphate absorption.
While anaemia is common in dialysis patients, it does not typically cause itching. Polycythaemia, which can occur in patients with polycystic kidney disease due to excessive erythropoietin production, can cause itching, but this is unlikely to be the cause of itching in this patient with end stage renal failure. Hypovolaemia may cause dry skin, but it is unlikely to cause an itchy rash. Hypophosphataemia is also extremely unlikely in renal patients and does not tend to cause itching.
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This question is part of the following fields:
- Nephrology
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Question 28
Correct
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You are considering commencing a patient in their 60s on cilazapril. In discussion with the patient you mention that this is an ACE inhibitor.
The patient asks you what 'ACE' is.
What is the primary function of 'ACE'?Your Answer: Conversion of angiotensin 1 to angiotensin 2
Explanation:The Renin-Angiotensin-Aldosterone System
The renin-angiotensin-aldosterone system is a pathway in the body that regulates blood pressure and fluid balance. It begins with the production of angiotensinogen in the liver, which is then converted to angiotensin 1 by the enzyme renin, produced in the kidneys. Angiotensin 1 is then converted to angiotensin 2 by the enzyme ACE, found in the lungs and kidneys. Angiotensin 2 has several functions, including the stimulation of aldosterone production by the adrenal gland. This hormone promotes the retention of sodium and water in the body, leading to an increase in blood volume and blood pressure.
This pathway is commonly tested in medical school and beyond due to its clinical relevance in conditions such as hypertension and heart failure. the renin-angiotensin-aldosterone system is crucial in the management of these conditions, as medications that target this pathway can be used to lower blood pressure and improve outcomes.
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This question is part of the following fields:
- Nephrology
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Question 29
Correct
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A 68-year-old man with a history of chronic obstructive pulmonary disease and overweight presents to his GP with severe hypertension. Upon investigation, he is diagnosed with renal artery stenosis. What is a risk factor for the development of renal artery stenosis in this patient?
Your Answer: Smoking
Explanation:Renal Artery Stenosis and its Risk Factors
Renal artery stenosis is a common cause of hypertension that occurs when the renal arteries become narrowed, reducing blood flow to the kidneys. This condition can be unilateral or bilateral and can lead to the release of renin, which stimulates aldosterone production through the renin-angiotensin-aldosterone system (RAAS).
Individuals with a history of COPD are likely to have a smoking history of at least 20-pack years, if not more. Although COPD can be caused by other factors such as alpha-1-antitrypsin deficiency or coal mining, the presence of COPD in a patient’s medical history should raise suspicion of a smoking history.
The most common cause of renal artery stenosis is atherosclerotic disease, which shares similar risk factors with cardiovascular and peripheral vascular disease. These risk factors include smoking, hypertension, female gender, hypercholesterolemia with low HDL cholesterol and high LDL cholesterol, diabetes, and peripheral vascular disease and erectile dysfunction, which are indicative of arteriopathy/atherosclerosis.
In summary, renal artery stenosis is a condition that can lead to hypertension and is commonly caused by atherosclerotic disease. Individuals with a history of COPD should be evaluated for smoking history, and those with risk factors for cardiovascular and peripheral vascular disease should be monitored for the development of renal artery stenosis.
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This question is part of the following fields:
- Nephrology
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Question 30
Incorrect
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A 60-year-old woman has been referred to the hypertension clinic due to her two-year history of hypertension and current use of chlorthalidone. Her physician suspects that there may be an underlying secondary cause for her hypertension and wants to investigate further. During her clinic visit, she mentions recent illness with gastroenteritis. Blood tests taken today show a renin level of 120 pmol/l (normal range: 10-60) and an aldosterone level of 1215 pmol/l (normal range: 100-800). What is the most likely explanation for these results?
Your Answer: Treatment with an ARB
Correct Answer: Hypovolaemia
Explanation:Factors Affecting Renin and Aldosterone Levels
Renin and aldosterone levels are important in diagnosing primary hyperaldosteronism, but they can be influenced by various factors. Hypervolaemia can cause a decrease in both renin and aldosterone levels, while hypovolaemia can lead to an increase in both. In primary hyperaldosteronism, renin levels decrease while aldosterone levels increase. The use of ACE inhibitors and ARBs can also affect renin and aldosterone levels, causing an increase in renin and a decrease in aldosterone.
In cases where renin and aldosterone levels are abnormal, it is important to consider other factors that may be contributing to the results. For example, hypovolaemia can be caused by diuretic therapy or an intercurrent illness such as gastroenteritis. When hypovolaemia occurs, it stimulates the production of renin and activates the renin-angiotensin-aldosterone system (RAAS), leading to an increase in aldosterone production. Aldosterone then acts to increase sodium and water retention by the kidneys, ultimately increasing intravascular volume.
In summary, the various factors that can affect renin and aldosterone levels is crucial in accurately diagnosing and treating conditions such as primary hyperaldosteronism. Repeat testing may be necessary in cases where other factors, such as hypovolaemia, may be influencing the results.
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This question is part of the following fields:
- Nephrology
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