Fluids, Electrolytes, Renal

Question 1

How do TBW, ECF and ICF change with gestational age?

Answer 1

TBW and ECF decrease

ICF increases

Question 2

Where is fluid lost from during early weight loss?

Answer 2

ECF

Question 3

How do you correct free water deficit?

Answer 3

4 ml/kg for every 1 mEQ of Na over 145

If Na is over 170, give 3 mL/kg of free water

Question 4

What are the 2 major sources of insensible evaporative water loss?

Answer 4

1/3 from respiratory tract

2/3 from skin

Question 5

When is ADH present in the fetus?

Answer 5

11 weeks

Question 6

Where is ADH formed and stored?

Answer 6

Formed in paraventricular and supraoptic ventricles in hypothalamus and stored in the posterior pituitary

Question 7

When is ADH secreted and where does it act?

Answer 7

Secreted in response to increased plasma osmolality
Acts on distal collecting tubule, and cortical+medullary collecting ducts. Increases the permeability of the cortical and medullary collecting ducts to reabsorb water

Question 8

What are the serum Osm, urine Osm, UOP and plasma ADH levels in SIADH, nephrogenic DI and central DI?

Answer 8

SIADH: Increased ADH, decreased serum Osm, increased urine Osm, decreased UOP

Central DI: Decreased ADH, increased serum Osm, decreased urine Osm, increased UOP

Nephrogenic DI: Normal or increased ADH, increased serum Osm, decreased urine Osm, increased UOP

Question 9

Urine Na in SIADH?

Answer 9

> 20 mEQ/L

Question 10

Genetic abnormalities leading to nephrogenic DI and mode of inheritance?

Answer 10

Vasopressin (V2) receptor defect - X-linked recessive

Aquaporin channel defect - Autosomal recessive

Question 11

How does pH change plasma K?

Answer 11

For every 0.1 unit reduction in pH, there is a 0.6 increase in plasma K

Question 12

Electrolyte abnormalities with Bartter syndrome?

Answer 12

Defects in electrolyte transport in loop of Henle
Hypokalemic, metabolic alkalosis with hypercalciuria
Triangular facies, protruding ears, large eyes, drooping mouth

Question 13

What other abnormalities is autosomal recessive PCKD associated with

Answer 13

Congenital hepatic fibrosis
Biliary dysgenesis
Hypertension, hyponatremia
Seen on prenatal ultrasound much later in gestation

Question 14

Renal agenesis occurs due to an embryological problem at which stage?

Answer 14

Failure of ureteric bud to differentiate

Question 15

ARPKD presentation

Answer 15

History of oligohydramnios and pulmonary hypoplasia as a consequence of poor fetal urine production, along with enlarged kidneys.
Renal ultrasonography demonstrates bilaterally enlarged kidneys with poor corticomedullary differentiation.
The renal cysts are small (<3 mm) and cannot be visualized on ultrasonography.
Congenital hepatic fibrosis