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CFT II > Exam 3 - Diabetic Ketoacidosis > Flashcards

Exam 3 - Diabetic Ketoacidosis Flashcards

1
Q

what is the fundamental trigger of DKA?

A

relative or absolute lack of insulin

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2
Q

what is an example of an absolute lack of insulin causing DKA in a patient? what about a relative lack of insulin?

A

absolute - no insulin at all, dog with untreated DM

relative - some insulin but not enough, concurrent disorder (pyelonephritis, pancreatitis) or receiving drugs (steroids) that can cause insulin resistance

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3
Q

in a healthy animal that is starved, what is the pathophysiology of DKA?

A

when a healthy animal is starved, insulin secretion drops but doesn’t stop completely & this puts a brake on the release of stored energy

pancreatic a cells progressively secrete more glucagon which promotes hepatic gluconeogenesis & triggers release of stored energy from fat (lipolysis)

fatty acids are converted by the liver into ketones - can be used to generate energy via the kreb’s cycle which can be used efficiently by the brain, heart, & other tissues

basal insulin secretion ensures that energy is released at an appropriate rate by limiting glucagon secretion limiting lipolysis

diabetic animals don’t have anything to slow down this process!!

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4
Q

what is the pathophysiology of DKA in a diabetic animal?

A

lack of insulin lets glucagon secretion continue unchecked - levels are markedly elevated despite hyperglycemia, so lipolysis moves at an accelerated rate

dog/cat with DKA produces ketones at 20X the rate seen with starvation which is way more than the body can use

patiently becomes progressively acidotic from the ketone production resulting in the generation of protons

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5
Q

how does hyperglycemia play a role in a diabetic animal developing DKA?

A

results in osmotic diuresis & involuntary water loss, so animal becomes progressively dehydrated which results in poor perfusion & then lactic acid production

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6
Q

how does deranged potassium homeostasis play a role in a diabetic animal developing DKA?

A

decreased intake, increased loss from the gi tract & urinary systems, & total potassium body stores become depleted

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7
Q

what are the 3 criteria needed for a diagnosis of DKA?

A

hyperglycemia

ketonemia/ketonuria

metabolic acidosis

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8
Q

T/F: if a patient is diagnosed with DM & has ketones in their urine at the time of diagnosis but are eating & drinking, they are still in DKA

A

false

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9
Q

what do you expect to see on a CBC of a patient in DKA?

A

stress leukogram expected - more obvious in dogs than in cats, but a degenerative left shift isn’t typical (indicates severe inflammation/infection)

cats may develop a hemolytic anemia secondary to heinz body formation triggered by ketoacidosis

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10
Q

T/F: in any patient with DKA, anemia carries a more guarded prognosis

A

true

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11
Q

what do you expect to see on a chemistry panel of a patient in DKA?

A

BG substantially elevated - rarely exceeds 600 mg/dl

bun/creatinine often increased - primarily due to dehydration, so pre-renal azotemia, but USG is impacted by renal glucosuria

abnormal liver enzymes - mainly ALP

may have increased bilirubin

acidosis

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12
Q

why is renal function difficult to evaluate in DKA patients?

A

they have a pre-renal azotemia due to dehydration but USG is impacted by renal glucosuria

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13
Q

what electrolyte derangements are seen in patients with DKA?

A

sodium - low to low normal from dilution effect of hyperglycemia & loss through vomiting

potassium - unpredictable, can be low or high

chloride - low, follows sodium

phosphate - usually low, follows potassium, worry about hemolysis if it gets too low

magnesium - likely will move down during fluid therapy, may need to supplement

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14
Q

what is seen on urinalysis in patients with DKA?

A

predictable substantial glucosuria - USG > 1.020 despite polydipsia

ketonuria

sediment exam may show infection

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15
Q

when would you take thoracic rads of a DKA patient?

A

indicated if heart disease is suspected

3-view study in a patient that has a fever to look for aspiration pneumonia

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16
Q

T/F: in dogs with DKA, > 2/3 of cases will have a positive cPLi result

A

true

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17
Q

what are the 4 main goals when treating a patient in DKA?

A
  1. restore circulating volume & correct dehydration
  2. anticipate & address electrolyte disorders
  3. turn off ketosis
  4. identify & address concurrent disorders (UTIs, pancreatitis, etc)
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18
Q

what are the 6 signs associated with ineffective circulating volume?

A
  1. very depressed/flat mentation
  2. poor gum color - pale, gray, muddy
  3. prolonged CRT, > 3 seconds
  4. tachycardia
  5. weak pulses
  6. cold extremities
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19
Q

what is the shock dose of fluids for dogs & cats?

A

dogs: 90 ml/kg

cats: 60 ml/kg

give 1/4 over 15 minutes & then reassess

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20
Q

how is % dehydration calculated for a DKA patient?

A

body weight (kg) X % dehydration - any fluids given during shock dose

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21
Q

how do you determine the time period in which you can correct dehydration for a DKA patient?

A

aim for 12 hours generally taking longer (24) in heart disease animals & shorter (6) in animals with severe pancreatitis, AKI, etc

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22
Q

what calculation is used for determining maintenance fluid requirements for a patient in DKA?

A

body weight ^ 0.75 X 130 - there is substantial polyuria, so it takes a lot of fluids to stand still

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23
Q

how should fluid therapy be initiated for a patient in DKA in regards to starting insulin therapy? why?

A

administer fluids for up to 4 hours prior to starting insulin

likely to drop the BG by 100 mg/dl

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24
Q

T/F: it is okay to wait until body fluid volume has been restored prior to administering insulin to a dog in DKA

A

false

25
Q

what standard fluid therapy monitoring should be done for DKA patients?

A

respiratory rate every hour

heart rate every 2 hours

body weight every 6-12 hours

urine output

26
Q

what is your best monitoring parameter for fluid overload?

A

respiratory rate

27
Q

T/F: major electrolyte derangements occur due to the rapid shifts in potassium & phosphorus in DKA patients, & failing to anticipate these shifts is a common cause of poor outcomes in DKA

A

true

28
Q

what is the equation for kmax?

A

kmax = 0.5 mEq/kg/hr

29
Q

if potassium is at the lower end of the reference range when you’re about to start fluid therapy in a DKA patient, how should potassium be supplemented? what should you do before starting insulin?

A

KCl added to the initial replacement IV fluids at 20 mEq/L - double check rate

need to recheck potassium, want to see if you made it into the reference range because insulin will drive potassium levels down a lot!

supplement potassium even if K is normal aiming for 40 mEq/L splitting between KCl & KPO4

30
Q

what is the only way to turn off ketosis in a DKA patient?

A

giving them insulin!!!!!

31
Q

T/F: you must start insulin within 6 hours of hospitalizing a DKA patient

A

false - within 4 hours

32
Q

how long is the onset & duration of action for regular insulin for IV administration for a patient with DKA?

A

onset within minutes

duration is < 1 hour

33
Q

what is the dose of regular insulin used for a CRI in a dog with DKA?

A

0.1 u/kg/hr or 2.4 u/kg/day

34
Q

what is the dose of regular insulin used for a CRI in a cat with DKA?

A

0.05 u/kg/hr or 0.1 u/kg/hr

35
Q

how is a bag for an insulin CRI made?

A

draw up the patient’s total dose of insulin & add it to a 250 mL bag of 0.9% NaCl

slowly run 50 mls through the line before attaching it to the patient

replace the bag every 24 hours

36
Q

T/F: no matter how large or small, a patient in DKA starts at 10 ml/hr of their insulin CRI

A

true

37
Q

how is a DKA patient’s insulin CRI rate determined during hospitalization? when is the patient switched to dextrose fluids?

A

CRI rate is adjusted based off of BG readings taken every 2 hours

when BG <250, bag is switched to dextrose so we can continue giving insulin - insulin shuts off glucagon secretion & stops lipolysis

38
Q

if a DKA patient has a BG >250, what is their insulin CRI rate? what fluid therapy is administered concurrently?

A

10 ml/hr

norm R or 0.9% NaCl

39
Q

if a DKA patient has a BG 200-250, what is their insulin CRI rate? what fluid therapy is administered concurrently?

A

7 ml/hr

0.45% NaCl with 2.5% dextrose

40
Q

if a DKA patient has a BG 150-200, what is their insulin CRI rate? what fluid therapy is administered concurrently?

A

5 ml/hr

0.45% NaCl with 2.5% dextrose

41
Q

if a DKA patient has a BG 100-150, what is their insulin CRI rate? what fluid therapy is administered concurrently?

A

5 ml/hr

0.45% NaCl with 5% dextrose

42
Q

if a DKA patient has a BG <100, what is their insulin CRI rate? what fluid therapy is administered concurrently?

A

insulin CRI stopped!!!!!

0.45% NaCl with 5% dextrose

43
Q

how long are insulin CRIs continued for in DKA patients?

A

until ketones are clearing & patient is able to eat

most patients are ketone negative within 72 hours of therapy - don’t stop prematurely because you can cause the ketonuria to start again

44
Q

why is it important to get calories into a DKA patient ASAP?

A

anorexia perpetuates the starvation response & drives ketosis

may need to place an NG tube or esophagostomy tube

45
Q

when can you start a longer acting insulin in a DKA patient?

A

when the patient is eating or is tolerating tube feeding

cats - glargine or protamine zinc
dogs - lente, NPH, or insulin detemir

46
Q

what monitoring should be done in DKA patients?

A

BG every 2 hours, urine output, body weight (very important!), electrolytes, respiratory rate, & pain level

47
Q

what is often the biggest issue in treating a DKA patient?

A

cost - $5,000-$6,000 for DKA at TAMU

48
Q

what should be done for management of a DKA patient in the first 4 hours of treatment?

A

baseline labwork, resuscitative fluids, calculate fluid deficit/maintenance needs, begin rehydration plan, assess K+, & pain meds/abx/gi meds

49
Q

what should be done for management of a DKA patient at hour 4 of treatment?

A

check hydration status, recheck electrolytes, calculate insulin CRI (have a buddy check - turn on by 4 hours), plan for K+ & P supplementation (default 40 mEq/L - give half as KCl & half as KPO4)

50
Q

what should be done for management of a DKA patient in hours 4-24 of treatment?

A

monitor BG every 2 hours, adjust insulin CRI as needed, monitor hydration status, reassess electrolytes (potassium every 4-6 hours & phosphorus every 12 hours), & check urine ketones

51
Q

what should be done for management of a DKA patient in hours 24-28 of treatment?

A

adjust insulin CRI as needed, address nutritional needs (NE tube, NJ tube, esophagostomy tube), ketones should be minimal, follow up on urine c&s, & plan on insulin transition

52
Q

what’s the problem that ketones cause for diabetics?

A

ketone bodies leave the liver & enter circulation where only limited amounts may be used

small amounts of glucose are needed to incorporate ketones into the citric acid cycle, you need insulin to get enough glucose into most cells, & lack of glucose crashes the kreb’s cycle

53
Q

T/F: DKA is not a consequence of hyperglycemia

A

true - reflection of excessive lipolysis

54
Q

T/F: severe hyperglycemia, >700 mg/dl, in a DKA patient suggests hyperosmolar syndrome

A

true

55
Q

what is hyperosmolar syndrome?

A

severe hyperglycemia, can be > 1,000 mg/dl

no or scant ketosis - likely some residual insulin production

concurrent renal or cardiac disease - severe azotemia is common

56
Q

T/F: hyperosmolar syndrome is more common in cats & has poor survival rates

A

true

57
Q

what ketones are identified by the urine dipstick?

A

acetoacetate & acetate

doesn’t pick up b-hydroxybutyrate

58
Q

why is nutritional support so important for cats in DKA?

A

hepatic lipidosis occurs quickly in cats - assume it’s going on if ALP & tbili are increased

59
Q

what are some poor prognostic factors associated with DKA?

A

anemia

severe acidosis

concurrent hyperadrenocorticism

hypocalcemia

substantial hepatic lipidosis

CFT II (28 decks)

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