DKA PBL

Question 1

K⁺ status in DKA

Answer 1

[K⁺]_serum is elevated but total body K⁺ is depleted due to osmotic diuresis and sometimes emesis

Question 2

What causes elevated [K⁺]_serum in DKA?

Answer 2

1. H⁺/K⁺ buffering: cells try to buffer acidosis by taking up H⁺, but have to eject K⁺ in order to maintain charge balance
2. Decreased Na⁺/K⁺ ATPase activity: insulin activates Na⁺/K⁺ ATPase, without it K⁺ cannot be pumped into cells → leaked back into interstitium → peritubular capillaries

Question 3

Tx of K⁺ status in DKA

Answer 3

monitor carefully

[K⁺]_serum will drop when Tx is initiated

supplement as needed

Question 4

Why does [K⁺]_serum decrease when DKA Tx is initiated?

Answer 4

1. Insulin pushes K⁺ into cells by upregulating activity of Na⁺/K⁺ ATPase
2. H⁺/K⁺ buffer is reversed, H⁺ is put back into plasma and K⁺ is put back into cells

Question 5

Carrier for Acyl-CoA into mitochondrial matrix

Answer 5

carnitine shuttle

Question 6

ABG findings in DKA

Answer 6

decreased HCO₃^-

decreased pCO₂

elevated H⁺

Question 7

Why is HCO₃ low in DKA

Answer 7

Le Chatelier’s principle:

H₂O + CO₂ ⇔ H₂CO₃ ⇔ H⁺ + HCO₃^-

you push this equation left by adding protons

Question 8

Why is pCO₂ low in DKA?

Answer 8

elevated H⁺ leads to increased respirations

→ blow off more CO₂ than you would normally

Question 9

Anion gap equation

Answer 9

[Na⁺] - ([Cl^- + HCO₃^-])

normally 8-10

Question 10

Osmotic diuresis

Answer 10

high amounts of solute in tubule lead to increased water retention in tubule

→ pee it out

Question 11

T_m glucose

Answer 11

transport maximum for glucose

normally Glc completely reabsorbed in proximal tubule, but when T_m is reached then you lose Glc in the urine

⇒ osmotic diuresis

Question 12

2 HLA genes associated w/ T1D

Answer 12

HLA-DR3

HLA-DR4

Question 13

Insulin _____

lispro

aspart

glulisine

Answer 13

rapid acting insulins

Question 14

Insulin _____

glargine

detemir

Answer 14

long-acting insulins

Question 15

What type of receptor is insulin receptor?

Answer 15

tyrosine kinase

Question 16

1˚ gain

vs

2˚ gain

Answer 16

1˚: positive reasons to use Tx → not sick

2˚: reasons patient would not take insulin, ie attention from boyfriend and others