renal objectives 8 and 9

Question 1

What is acute kidney injury (AKI)?

Answer 1

A sudden decline in kidney function characterized by decreased glomerular filtration and the accumulation of nitrogenous waste products in the blood.

Question 2

What can severe AKI lead to?

Answer 2

Uremia.

Question 3

Who can AKI occur in?

Answer 3

Both adults and children.

Question 4

What are the prerenal causes of AKI?

Answer 4

Hypovolemia (dehydration), shock (sepsis, neurogenic shock), and low blood pressure (poor perfusion to the kidneys).

Question 5

What are the intrarenal causes of AKI?

Answer 5

Postischemic or nephrotoxic acute tubular necrosis, malignant hypertension, acute pyelonephritis, renal artery/vein occlusion, high BP, kidney-related issues, medication or contrast toxicity.

Question 6

What are the postrenal causes of AKI?

Answer 6

Ureteral obstruction or bladder neck obstruction, often secondary to an enlarged prostate.

Question 7

What are the key manifestations of AKI?

Answer 7

An acute increase in BUN and serum creatinine.

Question 8

How do renal and urologic dysfunctions in children differ from adults?

Answer 8

In children, kidneys and urologic structures are still developing, and some disorders are due to congenital structural issues. In adults, these conditions can impact other systems significantly.

Question 9

What is unique about blood flow to a newborn’s kidney?

Answer 9

It primarily flows through the medullary nephrons, one of the three types of nephrons.

Question 10

Why is infant urine more diluted than adult urine?

Answer 10

Infants have shorter Loops of Henle, which leads to more diluted urine.

Question 11

What is the state of urea excretion in infants?

Answer 11

Infants are in a high anabolic state, so their urea excretion is low.

Question 12

Why is urea important in the kidneys?

Answer 12

Urea is required to establish the concentration gradient in the medulla.

Question 13

What is the safety margin for chemical balance in infants?

Answer 13

Infants have a narrow safety margin with high hydrogen ion concentration, low osmotic pressure, and limited ability to regulate their internal environment.

Question 14

When do the kidneys reach adult size?

Answer 14

Kidneys reach adult size by adolescence, increasing 10-fold in weight from birth.

Question 15

Why is water reabsorption diminished in children?

Answer 15

Immature kidneys and smaller tubule surfaces diminish the water reabsorption response to antidiuretic hormone (ADH).

Question 16

How does immature tubular transport capacity affect children?

Answer 16

It limits their ability to excrete potassium, reabsorb bicarbonate, or buffer hydrogen with ammonia.

Question 17

What conditions can rapidly lead to acidosis and fluid imbalance in children?

Answer 17

Diarrhea, infection, fasting, and poor feeding.

Question 18

How does total body water (TBW) change after birth?

Answer 18

TBW does not significantly change after birth but shifts location, with extracellular fluid (ECF) in newborns being nearly double that of adults.

Question 19

When does the decrease in ECF occur in children?

Answer 19

During periods of rapid growth, such as infancy and adolescence.

Question 20

What is the difference in water exchange between infants and adults?

Answer 20

Adults exchange about 2000 mL of water daily (5% of total body fluid, 14% of ECF), while infants exchange 600-700 mL (290% of total body fluid, nearly 50% of ECF), making hydration control more challenging.