L16 Chronic Kidney Disease Flashcards
Calculating eGFR and when most complications of AKD present?
Formulas used to calculate eGFR assume your body is in steady-state (i.e. not unwell)
Most complications of CKD present when eGFR is <20
Metabolite measures to caclulate renal filtration?
Kidney filtration commonly calculated w/ Creatinine (final byproduct of skeletal muscle breakdown) - affected by Non-renal determinants (i.e. Race, Sex, Age and weight)
New endogenous measurement is Cystatin C (a breakdown product of all nucleated cells)
Target blood pressure in CKD patients??
Goal of therapy for treating CKD?
120/80 (diabetic and non-diabetic)
Goal of therapy is to reduce proteinuria and treat hypertension. This is achieved through SGLT2i and ACEi/ARBs
Most common causes of Chronic Kidney Disease?
T2DM and Hypertension
Albuminuria > ________ increases the risk of chronic kidney progression. Why is this? Therapy?
Albuminuria > 30mg/g increases the risk of progression
Protein is harmful to the kidney and overtime can lead to fibrosis of the kidney
Goal of therapy is to reduce proteinuria and treat hypertension. This is achieved through SGLT2i and ACEi/ARBs
MOA of Nephroprotective Medications?
ACEi/ARBs: dilate the efferent arteriole thus reducing back pressure. Reduced pressure (lower GFR) at the glomerulus means less protein is pushed into the urine.
Blocking the RAAS also reduces Na+ absorption – Water follows Salt and therefore reduces blood volume.
SGLT2i: FLOZINATORS:
1. Blocks Na & Glucose absorption at Proximal tubule=> Na and Glucose wasting into urine – Water follows both =>diuresis effect reduces blood volume =>Lower blood volume = lower BP= Less scaring of kidneys
- High salt to macula densa (due to wasting from blockage above) leads to Tubuloglomerular feedback activation=> AFFERENT arterial constricts and reduces GFR (less blood getting through a smaller space)=>Lower GFR means less protein reaching glomerulus and less wasting in the urine
Toxicity of Nephroprotective medications?
WHEN SICK STOP ALL NEPHROPROTECTIVE MEDICATIONS (Can become nephrotoxic)
When you are unwell the haemodynamics of your body change. We need our normal reflexes (e.g RAAS activation, afferent arteriole dilatation) to maintain your GFR. If we DON’T hold those medications, you can lead to an acute kidney injury because GFR has dropped too low. This can lead to all the problems of AKI and in some cases the need for Dialysis!!
Chronic Kidney Disease Complications?
Anemia: Chronic Kidney Disease commonly leads to Iron dysregulation and low EPO levels
Mineral Bone Disease: Chronic Kidney disease leads to:
LOW Calcium and Vit D levels
High Phosphate and PTH (secondary Hyperparathyroidism)
Acidosis +/- Hyperkalemia: Metabolic Acidosis secondary to Uremia and impaired acid secretion
Treatment of Anemia due to chronic kidney disease? When to start?
When HB <10 we start treating
Oral or IV Iron replacement (eGFRs <20 – IV (Ferrinject))
TSATS <20% and Ferritin <200mmol/L = Give Iron
B12 replaced by subcutaneous injections
Folate Replaced: Folic Acid 5mg Weekly
Important: Replace components first then EPO
Once Iron/b12/folate has been replaced wait 2 weeks and recheck Hb
Try to avoid Blood Transfusions incase they need transplant in the future
Pathogenesis Leading to Mineral Bone Disease in Chronic Kidney Disease?
First, active Vit D levels are reduced (1α-hydroxylase needed to cover to Calcitirol)=> leads to LOW calcium levels=> Phosphate levels accumulate due to inability to excrete phosphate=> low Ca and High PO4 leads to SECONDARY Hyperparathyroidism=> High PTH levels try to stabilize the calcium and phosphate levels at the expense of the bones (i.e. Calcium is taken from the bones)
Treatment of Mineral Bone Disease?
Treatment of Vit D, Ca, and PO4
Start with inactive Vitamin D: Calcichew D3F (Calcium carbonate + Cholecalciferol) One Tablet OD
If Calcium levels very low/not responding to inactive form => give Calcitriol (active Vit D)
High Phosphate – start with Renal Diet (low K, Low Protein, and Low Phos) High Non-compliance rate!!
Can Give Phosphate Binders to bind in the GI tract and excrete it
Treatment of Hyperparathyroidism
To reduce PTH levels you must first replace the Vit D, Ca and lower Phosphate levels
If PTH levels still above normal limits despite treating, then use a calcimimetic (Cinacalcet): Acts by increasing the sensitivity of the gland to Calcium levels effectively lowering PTH levels
Threshold/Treatment of Metabolic Acidosis/Hyperkalemia?
Metabolic acidosis: pH <7.35, Bicarbonate < 22mmol/L
Treatment for Acidosis/Hyperkalemia: Sodium Bicarbonate
SE: Chalky Taste, Increase BP, GI upset
When to Dialyze Chronic Kidney Disease?
A – Acidosis that is refractory to medical management (i.e. IV or Oral NaHCO3)
E – Electrolyte abnormalities refractory to medical management (Usually hyperkalemia - toxic to myocardium)
I – Intoxication (e.g. metformin, methanol)
O – Overload refractory to medical management (Diuretics => pulmonary edema)
U – Uremic (Grade ¾ encephalopathy or Uremic Pericarditis)
In outpatient setting main reasons to initiate dialysis: Fatigue, Weight loss, Itch
Types of Hemodialysis? Indications for each?
1. Continuous Renal Replacement Therapy (ICU Setting)
“gentle” form of dialysis as it removes a small amount of fluid at a time
People on ionotropic support or low BP (<90mmHg) can dialyze through this method (Cardiogenic/hypovolemic shock)
2. Intermittent Hemodialysis (Usually 2-3 days/week)
Usually in chronic ESRD patients but can be used in acute settings if BP >90mmHg
Access for Hemodialysis Lines? Uses of each
Central or Femoral Line (Temporary lines that are quick to place and provide central access for blood, IV medications and Dialysis. Increased risk of infection, done in emergency settings
Permacath (Tunneled Catheter): Catheter tunneled under the skin to reduce the risk of infection. Can stay in long-term
Fistulas: Vascular surgery where you attach a vein to an artery. The high flow of the artery causes the vein to be ”arterialized” which is then used to pump the blood through the IHD machines. Preferred due to decreased risk of infection and allows the patient to maintain most activities of daily living
Peritoneal Dialysis (PD): Uses peritoneal membrane as barrier to filter electrolytes, fluid, and toxins out of the blood. “Access” is through a tenchkoff catheter and the pig tail end sits in the pelvic cavity. Multiple bags are drained into and out of the abdomen over night/day
