Chronic Kidney Disease, ESRD, and Dialysis Flashcards
Albuminuria indicates increased risk of developing ESRD. Why might this be the case?
It is thought that this is because albuminuria is a marker for secondary focal and segmental glomerulosclerosis, which gradually leads to additional nephron loss and renal disease progression.
Goals of screening for CKD
- Slow the decline in GFR
- Reduce complications of declining kidney function
- Prepare patient for ESRD or kidney transplant
The way to think about CKD
There is no new process going on, and the individual tubules are not handling their contents differently. There are just fewer nephrons.
And, as a result, the kidney cannot do all of the tasks that require the input from many nephrons to accomplish. It is a problem of scale.
Complications of CKD
- Hypertension
- Hyponatremia
- Hyperkalemia
- Metabolic acidosis
- Secondary hyperparathyroidism
- Cardiovascular disease
- Anemia and functional iron deficiency
Hypertension and CKD
Hypertension is a cause, a symptom, and a consequence of CKD.
With fewer nephrons, the body cannot excrete a given salt and water load as easily as it could with a full set.
Treating hyperkalemia in CKD
- Hyperkalemia develops because there are not enough nephrons to secrete the potassium load
- Low potassium diet
- Medication changes to limit interference in potassium secretion
- Diuretics
- Polystyrene resins that sequester intestinal potassium
Metabolic acidosis in CKD
- Less ammoniagenesis
- As a consequence, lower urinary buffer capacity AND less new bicarbonate production in the kidney
- Less/slower clearance of non-volatile acids
- CKD is a catabolic state, resulting in greater protein breakdown and production of non-volatile acids
- Result is an anion gap and non-anion gap acidosis
Bicarbonate supplementation in CKD
Supplementation with bicarbonate once patients lose the ability to adequately produce novel bicarbonate in their kidney actually slows decline in kidney function and can give patients a year or more of dialysis-free survival.
Demineralization of bone goes hand-in-hand with ___.
Demineralization of bone goes hand-in-hand with mineralization of the vasculature.
This explains why patients with secondary or tertiary hyperparathyroidism due to CKD are the ones who are at risk of cardiovascular disease.
Anemia in CKD
- Seen when eGFR < 35
- After ruling out other causes (especially iron deficiency), anemia is presumed to be due to EPO or EPO resistance - there is no need for an EPO measurement.
- EPO supplementation is started
- Target Hgb is 10-11 g/dL
- Attempting to go over this may require doses of EPO so high that they cause extramedullary hematopoiesis, so this is avoided if possible
- Iron deficiency secondary to EPO treatment is common
Caveat to the term “uremia”
Uremia is when blood urea is elevated, and the uremic syndrome is associated with toxic symtpoms and elevated urea.
HOWEVER, urea is not toxic. Instead, we are using it as a marker of other toxic things in the blood that rise in parallel, but have yet to be identified.
So, while uremia is a dangerous condition, it is not because of the “uremic” part per se. It is because of the other associated things that go along with it.
Manifestations of the uremic syndrome
The list goes on even more - anemia, platelet dysfunction, pruritis and dry skin, immunocompromise, growth retardation, sexual dysfunction, imparired insulin breakdown, osteomalacia/rickets, B2 amyloidosis, myopathy, soft connective tissue calcification, weight loss, “uremic fetor”, hypothermia, edema, and electrolye disturbances.
So, basically, everything.
Indications for implementing diaylsis
- Uremic syndrome
- Electrolyte abnormalities or volume overload refractory to pharmacologic and dietary management
- Evidence of malnutrition
- Not a rule, but usually when GFR < 10 mL/min
Renal replacement therapy
- Hemodialysis
- Peritoneal dialysis
- Active medical care without dialysis
- Kidney transplant
ESRD Medicare cut-out
Dialysis is one of the few cut-outs that Medicare will address for individuals who do not otherwise qualify for Medicare. (Another being ALS)
It covers 80% of the costs of dialysis.
How do we tell if dialysis is working, or if we are doing it frequently enough?
We monitor urea!
Again, urea is not itself dangerous, but is a very useful marker by association.
Barriers to dialysis
- Cost (even with help from Medicare)
- Availability of instruments
- Anticoagulation (you must be on anticoag to use dialysis)
- Presence of a “marker” for tracking progress - almost always urea, but if there is no marker we don’t know how to monitor someone’s progress on dialysis
- Availability of venous access - particularly a problem for long-time dialysis patients, as scarring from repeated use will make a vein no longer viable for use in dialysis.
Dialysis by diffusion
Dialysis by convetion
Typical dialysis treatment
Hemodialysis pros and cons
Peritoneal dialysis
Peritoneal dialysis pros and cons
Where is a transplanted kidney placed?
In the iliac fossa!
Post-kidney-transplant medications
Pros and cons of different types of dialysis
Differential for PCOS
Dietary and pharmaceutical treatments for CKD-induced anemia
Dietary and pharmaceutical treatments for CKD-induced secondary hyperparathyroidism
Dietary and pharmaceutical treatments for CKD-induced acidosis
Dietary and pharmaceutical treatments for CKD-induced hyperkalemia
Dietary and pharmaceutical treatments for CKD-induced nutritional deficiencies
