Pathophysiology of Acute Kidney Disease

Define Acute Kidney Injury

An abrupt (days to weeks) decrease in glomerular filtration rate (indicated by an increase in serum creatinine)

Why is the accumulation of uremic toxins concerning in AKI?

Because it can cause GI symptoms and neurological complications

How does AKI contribute to volume overload?

Impaired kidney function reduces fluid excretion, leading to volume overload, which can cause hypertension, edema, and pulmonary congestion

Why is hyperkalemia dangerous in the context of AKI?

AKI impairs potassium excretion, leading to hyperkalemia, which can cause life-threatening arrhythmias

What acid-base disturbance is commonly seen in AKI and why?

Metabolic acidosis occurs due to decreased acid excretion and impaired bicarbonate reabsorption

How does AKI affect medication management?

KI can cause accumulation of medications that are normally metabolized or excreted by the kidneys, increasing the risk of toxicity

What are some characteristics that can help to differentiate AKI from CKD?

1. History and Physical Exam

2. Urine output (oliguria would suggest AKI)

3. Kidney imaging (an ultrasound or cross sectional imaging like a CT scan)

4. Other labs

If you saw small or atrophic kidneys in kidney imaging, does that suggest AKI or CKD

CKD

If you had normal or large sized kidneys, that would suggest

AKI

Which conditions don’t show an altered kidney size in CKD?

Polycystic kidney disease, diabetes, amyloid

What are some labs that can suggest CKD?

Anemia, or secondary hyperparathyroidism

Many patients with AKI are

Anemic