MET3 Revision: Renal II Flashcards
What are the two ways of classifying CKD? [2]
Via GFR; and albumin excretion
What are the classifications of CKD by GFR? [5]
· Stage 1: any kidney problem, but eGFR >90
· Stage 2: any kidney problem, eGFR 60-90
· Stage 3a: eGFR 45-59
Stage 3b eGFR 30-44
· Stage 4: eGFR 15-30
· Stage 5: eGFR < 15
What are the classifications of CKD by albuminuria? [6]
A1:
* Albumin excretion (mg/24hr): < 30
* ACR: < 3
A2:
* Albumin excretion (mg/24hr): 30-300
* ACR: 3-3-
A3:
* Albumin excretion (mg/24hr): >300
* ACR: >30
What are primary renal disease causes of CKD:
Glomerular [1]
Tubolinterstitial [1]
Blood flow [1]
Cystic / congenital [1]
Transplant [1]
What are primary renal disease causes of CKD:
Glomerular: MCD; membranous nephropathy
Tubolinterstitial; UTI; pyelonephritis; stones
Blood flow: renal limited vasculitis
Cystic / congenital: renal dysplasia
Transplant: recurrence of renal disease
What are systemic causes of CKD:
Glomerular [1]
Tubolinterstitial [1]
Blood flow [1]
Cystic / congenital [1]
Transplant [1]
What are systemic causes of CKD:
Glomerular: diabetes; amyloid
Tubolinterstitial: drugs, toxins, sarcoid
Blood flow: heart failure
Cystic / congenital: alport syndrome
Transplant: rejection, calcineruin toxicity
Who manages stages 3-5 of CKD? [3]
Stage 3 CKD with eGFR 30-60: the most important effect of this is the increase on your vascular risk: mostly managed by GP to reduce vascular risk and prevent progression of CKD to the point where it needs serious intervention + likely dialysis.
Stage 4 CKD: is also quite poor kidney function and will likely need nephrology attention.
Stage 5 CKD: patients need immediate nephrology attention and are very close to needing dialysis.
State 5 pathological systemic consequences of CKD [5]
Anaemia
Renal bone disease
HTN
Acid / base imbalance
Uraemia
(Basic roles of the kidneys
- Get rid of fluid (and sodium)
- Control serum pH
- Control serum potassium
- Regulate BP
- Regulate Hb via EPO production
- Control bone and mineral metabolism both through Ca/PO excretion and through Vit D
So, in cases of CKD, all of these things go wrong as they cannot go ahead as normal like they do in a healthy kidney)
Describe how anaemia can occur due to CKD [5]
Which stage of CKD does this occur in? [1]
- Reduced secretion if EPO; relative deficiency
- Reduced erythropoiesis due to toxic effects of uraemia on bone marrow
- Reduced absorption of iron
- Anorexia due to uraemia
- Reduced RBC survival}}
G3B+
How can acidosis occur due to CKD? [2]
Increased tendency to retain hydrogen ions (due to abnormalities in acid-base homeostasis)
Leads to low levels of bicarbonate
Describe what the mineral disturbances in CDK MBD (CKD mineral bone disorder) are [3]
Disturbances in Ca & P metabolism, causing:
High serum phosphate (reduced excretion)
Low vitamin D activity - causing low serum calcium (healthy kidneys metabolise vitamin D into it’s active form, which is essential for Ca reabsorption& regulating bone turnover
What are the pathological consequences of low Ca2+ in CKD MBD? [3]
Low serum calcium and high serum phosphate causes the parathyroid glands to excrete more PTH: secondary hyperparathyroidism.
PTH stimulates osteoclast activity, increasing calcium absorption from bone. This results in osteomalacia
What is the name for this radiographical finding of CKD MBD? [1]
Describe why this occurs [2]
Rugger jersey spine
Sclerosis of both ends of each vertebral body (denser white)
Osteomalacia in the centre of the vertebral body (less white)
How do you manage CKD MBD? [3]
· Vitamin D analogues & dietary supplements
· Dietary restriction of phosphate and prescribe phosphate binders around the time of meals
· Calcimimetics: bind to PTH receptors and mimic the normal action of calcium to prevent PTH release
What level of serum P do you treat CKD bone-mineral disease at? [1]
P > 1.5mmol/L
What is the BP aim for patients with CKD? [1]
What is the BP aim for patients with CKD & DM or ACR > 70? [1]
What is the BP aim for patients with CKD? [1]
* < 140/90
What is the BP aim for patients with CKD & DM or ACR > 70? [1]
:< 130/80
When should you refer a patient to a renal specialist? [5]
- eGFR less than 30 mL/min/1.73 m2
- Urine ACR more than 70 mg/mmol
- proteinuria > 30 mg/mmol & haematuria
- Accelerated progression (a decrease in eGFR of 25% or 15 mL/min/1.73 m2 within 12 months)
- 5-year risk of requiring dialysis over 5%
- Uncontrolled hypertension despite four or more antihypertensive
Describe the managment for CKD patients:
To slow disease progression [2]
To reduce risk of complications [1]
Slow disease progression:
- ACE inhibitors (or angiotensin II receptor blockers)
- SGLT-2 inhibitors (specifically dapagliflozin)
To reduce risk of complications:
- Atorvastatin 20mg (prevents CV disease)
Which CKD patients should be offered ACE inhibitors? [3]
When is a SGLT-2 inhibitor be given to CKD patients? [1]
ACE inhibitors are offered to all patients with:
* Diabetes plus a urine ACR above 3 mg/mmol
* Hypertension plus a urine ACR above 30 mg/mmol
* All patients with a urine ACR above 70 mg/mmol
SGLT-2 Inhibitors
Dapagliflozin is the SGLT-2 inhibitor licensed for CKD. It is offered to patients with:
* Diabetes plus a urine ACR above 30 mg/mmol
Describe the MoA of thiazide-like diuretics [1]
- Block Na/Cl channel from urine into DCT
- Blockage of the Na/Cl channel increases the flow of ions through the Na/Ca channel, resulting in increased calcium reabsorption into the interstitium in exchange for Na return to the DCT.
Name 4 AV fistula features to examine in an OSCE
Skin integrity
Aneurysms
Palpable thrill (a fine vibration felt over the anastomosis)
A “machinery murmur” on auscultation over the fistula
Describe how an AV fistula works for dialysis [3]
An AV fistula is an artificial connection between an artery and a vein. It bypasses the capillary system and allows blood to flow under high pressure from the artery directly into the vein.
This provides a permanent, large, easy-access blood vessel with high-pressure arterial blood flow.
Creating an A-V fistula requires a surgical operation and a maturation period of 4-16 weeks before it can be used.
Which three locations can an AV fistula be placed in? [3]
Radiocephalic fistula at the wrist (radial artery to cephalic vein)
Brachiocephalic fistula at the antecubital fossa (brachial artery to cephalic vein)
Brachiobasilic fistula at the upper arm (less common and a more complex operation)
What is STEAL syndrome of an AV fistula? [2]
Inadequate blood flow to the limb distal to the fistula.
The AV fistula “steals” blood from the rest of the limb.
Blood is diverted away from the part of the limb it was supposed to supply, leading to ischaemia. Instead, it flows through the fistula and into the venous system.
Describe the process of peritoneal dialysis [3]
Peritoneal dialysis uses the peritoneal membrane to filter the blood.
A special dialysis solution containing dextrose is added to the peritoneal cavity.
Ultrafiltration occurs from the blood, across the peritoneal membrane, into the dialysis solution. The dialysis solution is replaced, taking away the waste products that have filtered out of the blood.
