Chronic Kidney Disease and Dialysis: Pathology Final

Epidemiology of kidney disease

-1/10 canadians have kidney disease

- 50,000 people requiring transplant or renal replacement therapy

- 10th leading cause of death in Canada

Definition of chronic kidney disease

- GFR less than 60ml/min AND 1 or more markers of kidney damage

- Protein in urine

- Urine sediment abnormalities

- Persistent blood in urine

- Electrolyte disturbances

- Histology abnormalities

- Structural abnormalities seen by imaging

- History of kidney transplant

Classification/staging of CKD is based on the following factors

- GFR

- Proteinuria

Even if you have a decent GFR, if you have high protein in the urine it be a higher staging

5 stages overall

When should you use creatinine, cystatin C, or 24 hour collection/nuclear test for eGFR

Creatinine is the one used first, but if you suspect it is wrong other things can be used

Cystatin C can be used when there is a patient with low muscle mass, medications that alter tubular secretion, obesity, or very high/low protein diet

If you suspect cystatin C is wrong or cannot get access to it then can do 24 hour urine collection or nuclear test

Measuring proteinuria

Done by albumin to creatinine ratio or protein to creatinine ratio (typically albumin)

Correlates to the 24 hour urine collection, multiply it by 10 to get the total protein in the urine per day

Determining the cause of CKD

Not enough to just say someone has CKD, must determine the underlying cause by doing the following:

- Physical exam

- Symptoms

- Social and environmental history

- Family history

- Lab testing

- Medical history (especially for things like diabetes, hypertension, or autoimmune conditions)

- Nephrotoxic medications

Progression of CKD

Normal > Increased risk > Damage > Decreased GFR > Kidney failure > Death

Cannot go backward, but the goal is to prevent going forward. Screening people for risks, addressing risks, treating comorbid conditions, preparing patient for replacement therapy, etc

Kidney failure risk equation

Based on age, sex, country, GFR, proteinuria can determine risk of kidney failure

Put patient into categories accordingly: Lower risk can go see a nephrologist, higher risk can go to a multi care kidney clinic, and higher risk can plan access and transplant

Cardiovascular risk in CKD

As GFR decreases, CV risk increases

Leading cause of death of patients with CKD

If the GFR is also increased more than 75 the risk goes up, but this may be because creatinine is not reliably measured below 60mL/min and also because of proteinuria

Why is there a risk for CVD in CKD

Because of uremia-related risk factors:

- Oxidative stress

- Endothelial dysfunction

- Insulin resistance

- Uremic bone disease

On top of the traditional risk factors they now have more. Try to minimize traditional risks because it is harder to minimize the risks associated with CKD

Non-pharmacological strategies from preventing CKD progression

- Exercise

- Low sodium diet

- Normal protein diet, no excess in protein

- Smoking cessation

- Weight loss (if applicable)

- Renally dosing medication

- Holding off on NSAIDs/IV contrast

- Sick day counselling, if patient is feeling sick can stop ACEi until they are feeling better

Pharmacological management of CKD

- Every patient gets SLGT2i

- Every patient gets RAS inhibitor (control blood pressure)

Pharmacological management for people with CKD and diabetes

Can add GLP-1 RA when indicated, as well as ns-MRA

SLGT2i in CKD

Causes an initial decrease in GFR but overall causes less decrease in GFR, should counsel patients on this

Reduces proteinuria and other positive effects for CKD

Proteinuria and impact on progression of kidney disease

Huge impacts, even if eGFR is decreased as long as protein is decreased there may actually be a reduction in risk of kidney failure

Complications of CKD

Metabolic:

- Hyperkalemia

- Metabolic acidosis

- Uremia

Hemodynamic:

- Hypertension

- Volume overload

- Cardiovascular disease

Endocrine

- Anemia

- Secondary hyperparathyroidism

- Low calcium

- High phosphate

What kind of symptoms does uremia cause

Encephalopathy which is marked by confusion and cognitive decline

Indications for starting dialysis for CKD

- Electrolytes: Hyperkalemia, hypocalcemia

- Volume overload

- Uremia (nausea, decreased appetite, encephalopathy, pericarditis)

Consequences of hemodialysis

Microvascular damage

Types of renal replacement therapy

- Hemodialysis

- Peritoneal dialysis

- Transplant (do not have to suffer the consequences of dialysis, preferred

Principles of dialysis

Diffusion and convection (solvent drag when applying pressure)

Hemodialysis access

- Arteriovenous fistula

- Arteriovenous graft

- Central venous catheter

Arteriovenous fistula

Surgeon connects artery and vein, allows easy access for hemodialysis because it is easily seen

Arteriovenous graft

If fistula cannot be made, can connect artery and vein by tube which allows access for hemodialysis

Central venous catheter

Inserted into neck, goes through large blood vessel into the heart

How often is hemodialysis performed

During the day: Short runs 2-3 hours x 5 days OR

Overnight: 7-8hrs x 5 days

Minimum of 12 hours per week

Where can hemodialysis be performed

In hospital or at home

How does hemodialysis work

Blood taken out, goes through blood pump which speeds up flow, heparin is inserted so clotting does not happen, goes through filter and then back into the patient

Filter: using diffusion and convection to filter toxins

Access for peritoneal dialysis

Catheter is inserted in the stomach away from the beltline (as to not cause infection) and the bottom of the catheter rests above the bladder

In cases where a patient has a larger stomach, the access can be higher up to make sure they can see/clean it

Peritoneal dialysis

Taking dialysis fluid and inserting into the peritoneal cavity and allowing diffusion and convection to happen to clear toxins

Must be done daily, more gentle method of cleaning

Recommended in younger patients to keep their vascular access

Can be done manually or with a machine

Can be done at home by patients/nurse

Manual PD

Done when patient works from home or has the opportunity

Multiple draining and filling during the day. Then fill the peritoneal cavity, sleep with it, and then wake up in the morning and drain

Cycler PD

Done when patient cannot fill and drain during the day

In the morning they fill the peritoneal cavity with fluid and then drain it at the end of their day. Then they are hooked up to the machine which does the filling and draining cycles throughout the night

Kidney transplant

Preferred option because dialysis comes with bad side effects

Can get kidney from a living or decreased donor

Paired exchange program

Matching kidney with the person in need

Wait time for kidney transplant

Depends on blood group and sensitization (how many antibodies you have)

Pros of kidney transplant

- Reduced mortality, hospitalization, and CV events compared to dialysis

- Better quality of life