Renal Week 5 Saq Questions Study Guide.Pdf

RENAL WEEK 5 SAQ QUESTIONS STUDY GUIDE 1. Lisa is an 80-year-old female. She presents with a blood pressure of 140/80 and feels very dizzy. You perform some investigations, and you find the following: eGFR of 30, urine lipstick is positive for proteinuria and a pH of 6. Her electrolyte studies reveal that her potassium levels are 5.9 and her PO4- levels are also elevated. An ECG reveals that her heart rate is 50 and PR intervals are 300. You find out from her daughter Lily 35 years old, that she has been having low urine output, and problems with her albumin for the past 4.5 months. a. Based on the given information what is the most likely diagnosis. Justify. (1.5 mark) b. Why is the Cockcroft-Gault mor reliable that eGFR? (1 mark) c. Explain how the acid/base balance of the kidney is affected. In your answer refer to how that will affect the anion gap. (2 marks) d. Based on your answer from part a, explain what her urine analysis and ECG results mean. (2 marks) e. How many this patient benefit from dialysis? (Hint: in your answer refer to which parts of the stimulus are an indication for dialysis) (2 marks) f. Explain one complication is at risk of. (2 marks) Answer: • • • • a. Chronic kidney disease, because there is evidence of kidney damage as there are albumin level issues for more than three months and although not necessary there is a decrease in eGFR for more than three months. b. Because it accounts for muscle mass, which tells us about Cr status. c. In CKD there is damage to the kidney parenchyma. The alpha intercalated cells will be damaged therefore, they will have a hard time excreted H+, so there is H+ in the blood. Meanwhile, the beta intercalated cells are also damaged, so there will be decreased HCO3- reabsorption into the blood. This will cause acidosis. d. The decrease in pH is due to the disturbed acid/base balance which is explained in part c. The increase K+ and PO4- is because of the reduced GFR so this will build up within the blood. The increase intervals of PR and her low heart rate is because there is increased K+, which causes hyperpolarisation of the heart and thus cause it to become bradycardic. e. In CKD there usually is a build of urea, which can cause things like encephalopathy. So, dialysis should be used. It is also good because there will be low protein, which will cause third spacing so dialysis will be good as there will be also increase volume retention. It will also correct the acid/base disturbances and the risen k+ levels, and hence help correct them. 2. Hannah is a 40-year-old female. From her medical history you find out that she is obese, has type two diabetes and is usually hypertensive and is taking an ACE inhibitor. She also has a moderate Crohn’s disease of which she is taking an NSAID for. She tells you that she has been having a reduced urine output and her urine has been becoming cloudy. a. What does her cloudy urine indicate and list three causes of this. (2 marks) b. Based on her presenting complaint what is the most likely diagnosis and explain the mechanism behind how diabetes and hypertension cause your hypothesized diagnosis. (5 marks) c. Based on her low urine output, you determine that she is in need of a diuretic. However, what changes to her medications would you need to make and why? (6 marks) Answer: a. • • • b. - - The cloudy urine is because of the presence of albumin. Minimal change disease Diabetic nephropathy Hypertensive nephropathy When there is diabetes there is increased glucose so more glucose will be filtered. The PCT will try to reabsorb that glucose, however the Na+/Glucose transporters saturate after 180. This means that excess glucose will not be reabsorbed and will spill in the urine. The increased glucose levels, in the afferent arteriole, through non enzymatic glycosylation, glucose and amino acids cause AGEs cross link, causing atherosclerosis. These trap LDL causing thickening of the vessel, which will reduce perfusion to the kidney so less blood and NaCl will reach the macula densa, of which through the tubloglmerlar feedback mechanism it will release NO and PGE2, of which can stimulate the JG cells to make renin. Which will increase fluid retention, and thus the body volume in attempt to increase perfusion to the kidney, however, this will cause some hyperfiltration which causes shear stress. In either case of the hypertension and the diabetes, there will be activation of the mesangial cells, of which cause the release of tissue growth factor beta activating fibroblasts which will cause fibrosis. This will cause thinking of the glomerular basement membrane and thus reduce GFR. c. If you give a diuretic, then this will cause a triple whammy effect (I am not bothered typing the whole thing hahhaha). To avoid that triple whammy effect, change the ACE-I to another blood pressure medication, like a beta blocker or a sympatholytic. 3. Answer the following questions about UTIs. a. Explain why a 65-year-old female is at more risk than a 65-year-old male. (2 marks) b. What is the most common microorganism that causes UTI? (0.5 mark) c. Why can blood cultures be problematic for patients who are on an antibiotic treatment? (1 mark) d. What type of adenovirus may cause a haemorrhagic cystitis and what tissue does it affect? (1 mark) Answer: a. Because females have a shorter distance from the anus to the urethra (3.5 – 5.5 cm), while in men the distance is about 10 cm. b. E. coli c. Because the antibiotics can spill and thus inhibit bacterial growth, which can give false and unreliable results. d. Serotype 11 comes from adenoid tissue. 4. Explain why in pre-renal AKI azotaemia may occur? Answer: This is because there is decreased GFR so less of urea and ammonia will get excreted. Moreover, since the tubules their function is usually intact, so reabsorption from the lumen of the nephron it is still ok, so some of that urea and ammonia that will happen to get filtered, will get reabsorbed into the blood. This will cause urea and ammonia build up which will go the brain, and thus cause confusion. 5. a. Describe the pathogenesis of Goodpasture syndrome. b. Using your answer for part a, explain why hypertension may occur. Answer: a. • • • • • • • • • This is where there is a mutation in the HLA-DR 15 gene. This will cause the immune system to recognise the 3 alpha collagen chain in the basement membrane as foreign. There is alpha 4 and 5 alpha chains, but 3 alpha is most affected as it is the most exposed. The there will be antibodies generated against them which are known as anti-GBM. This will target the basement membrane collagen fibres mentioned above. This will cause it to become damaged, thick and porous. This will allow proteins, RBCS and other things to leak through. The inflammation will activate mesangial cells which stimulate growth factors and fibroblasts. This will cause proliferation of the glomerulus and fibrosis. This will make it harder for the filtrate to pass through -> decreased GFR. b. Because there is the fibrosis and the sclerosis, this will clog up the lumen and cause hyalinization of the afferent arteriole. This means that less blood will be reaching the JG cells. As a result, the JG cells will secrete renin in thus activate RAAS to increased fluid/water retention. However, since the narrowed lumen issue has not been fixed, regardless of the activation of RAAS and how much it is getting activated, JG cells will keep activating RAAS. This will lead to too much fluid accumulating -> increased force/pressure acting on the vessel walls -> hypertension. 6. Name the six classifications of lupus nephritis. (6 marks) Answer: • • • • • • Minimal mesangial. Proliferative mesangial. Focal lupus. Diffuse lupus. Membranous lupus. Advanced sclerosing lupus.