Hypoglycemia Flashcards

1
Q

Hypoglycemia occurs via one of several mechanisms:

A
  1. excess insulin or insulin analogs
  2. excessive glucose utilization, and
  3. decreased glucose production
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2
Q

most common specific causes of hypoglycemia:
excess insulin:
excess utilization:
decreased production:

A

exogenous insulin overdose
insulinoma
other insulin analog–secreting tumors

sepsis

hypoglycemia of puppies and toy
hypoadrenocorticism

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3
Q

Neuroglycopenia causes alterations in mentation, seizures, blindness or alterations in vision, somnolence, and weakness or ataxia secondary to:

glucagon infusion may be used for cases of intractable
hypoglycemia secondary to:

A

low energy
adrenergic stimulation = restlessness, anxiety, tachypnea, vomiting or diarrhea, and trembling

insulinoma or insulin analog–secreting
neoplasms

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4
Q

gluconeogenesis is what:

A

production of glucose from precursors lactate (ketone to acytl-coA), pyruvate, amino acids, and glycerol

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5
Q

β cells - insulin, secreted in response to (3):

GI hormones:

A

glucose
amino acids
GI hormones:

gastrin
secretin
cholecystokinin
gastric inhibitory peptide

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6
Q

Glucagon MoA 4):

A

directly stimulates hepatic glycogenolysis
gluconeogenesis
mobilizes gluconeogenic precursors
reduces peripheral glucose utilization

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7
Q

Growth hormone antagonizes effects of insulin by:

A

decreasing peripheral glucose utilization

promoting lipolysis

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8
Q

neuroglycopenia:

Brain obligate energy source:

relies on a constant stream of glucose for its energy needs, enters via:

A

Glucose is an obligate energy source for the brain

limited ability to use other substrates
store minimal amounts of glycogen
cannot manufacture glucose

facilitated diffusion
arterial glucose essential to maintaining a diffusion gradient

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9
Q

How can some animals, especially those with prolonged hypoglycemia, demonstrate no associated CS:

A

upregulate cerebral glucose uptake

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10
Q

def hypoglycemia #:

Whipple’s triad provides guidelines for identifying hypoglycemia:

A

< 60, <50mg/dl CS

CS, low BG, abatement of CS with dextrose

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11
Q

Exogenous insulin overdose - duration of affect:

ddx cat DM low BG:

A

varies and is not dependent on the amount and type of insulin caused overdose

Once the animal is stabilized and eating, dextrose CRI tapered off while BG monitored

Some diabetic animals may not need insulin for several days

iatrogenic overdose
remission
not eating and dosed/concurrent sickness

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12
Q

Insulinomas are insulin-secreting, usually ____

more commonly in:

C/S: weakness or collapse, and severe hypoglycemia is an isolated finding

Dx: blood insulin concentration on a sample taken:
______ insulin levels in the face of hypoglycemia
are indicative of insulinoma

some intermittent and require:

A

malignant tumors

middle-aged to older dogs but also cats

during an episode of hypoglycemia
High or normal

supervised fast or multiple samples to identify

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13
Q

adjunct insulinoma dx.

amended insulin/glucose ratio (AIGR) can be calculated:
AIGR higher than 30 suggests insulinoma
fallen out of favor because:

fructosamine values may also lend support to a diagnosis:

Provocative testing such as:
no more sensitive than other tests and may precipitate:

A

amended insulin/

= (insulin 100) / (plasma BG - 30)
other causes of hypoglycemia
can also have an abnormal ratio

low

glucagon tolerance test, epinephrine stimulation test
hypoglycemia

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14
Q

dx: insulin:glucose ratio

Abdominal ultrasonography:

CT, MRI, scintigraphy, sx exploration:

CXR to look for

A

may or may not reveal a mass

other options for attempted identification insulinoma

mets

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15
Q

Tx:
hypoglycemia management:

longest survival tx:

what is considered tx of choice:

Surgery is still considered palliative b/c ___% metastatic disease evident at surgery and ___

Mx.
diet:

GC (counterreg. hormone):

diazoxide MoA:

A
  1. glucagon CRI
  2. try and avoid dextrose

combination of sx. excision & mx. management

surgical excision of the primary tumor and any
obvious metastases

50%
majority of the others have occult metastases

small, frequent feedings of a food low in simple sugars

glucocorticoids (prednisone 0.5 to 1 mg/kg q12h30)

diazoxide (10 mg/kg initially, up to 60 mg/kg q12h30)

directly inhibits pancreatic insulin secretion,
can be used in patients with refractory disease

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16
Q

adjunct tx:

streptozocin MoA:

somatostatin analogs i.e. octreotide MoA:

MST:

medical treatment only:
sx + mx:

LN + panc:
mets + panc:

months for dogs with disease confined to the pancreas and local

lymph nodes and less than 6 months for dogs with distant metasta-
ses.15 Another reported that 10% to 15% of dogs undergoing surgery

mx + sx max reported: 3

biomarker Ki67 index shows promise for predicting MST

A

selectively destroys pancreatic β cells

suppresses synthesis and secretion of insulin

74 days (2m)
381 days (1 yr)
18 months (1.5 yr)
< 6 months (1/2 yr) 

for dogs with distant metasta-
ses.15 Another reported that 10% to 15% of dogs undergoing surgery

1316 days (4yr) for dogs undergoing surgery + GC

17
Q

other ddx hypoglycemia
Artifact (3)*:

Excess Insulin

Insulin Analogs (6):

A

Artifact*

  1. Pseudohypoglycemia* (serum sat, RBC used BG)
  2. Handheld glucometer*
  3. Hemoconcentration

Exogenous insulin overdose

Insulinoma
Paraneoplastic syndrome
• Hepatomas, hepatocellular carcinoma (most common)
• Leiomyomas, leiomyosarcomas (most common)
• Pulmonary, mammary, and salivary carcinoma
• Lymphoma, plasmacytoid tumors
• Oral melanoma, hemangiosarcoma

18
Q

Toxins and medications (2) MoA

Excess Glucose Utilization

Exercise-induced (hunting dog) hypoglycemia

Decreased Glucose Production (3)
how much of liver must fail?

A

• Sulfonylureas -oral glucose-lowering agent - stimulate insulin secretion, enhance tissue sensitivity to insulin
• Xylitol - stimulation of insulin release from β cells
B-blocker

  • Sepsis
  • Babesiosis
  1. Neonatal hypoglycemia/toy breed
  2. Hepatic dysfunction (70%)
    • Portosystemic shunt
    • Inflammatory or infectious hepatitis
    • Hepatic lipidosis
    • Cirrhosis
    • Neoplasia
    • Glycogen storage disease
  3. Hypocortisolism
19
Q

Counterregulatory hormone deficiencies

B-blockers

Paraneoplastic
Polycythemia
Leukocytosis
Pregnancy

A
  • Glucagon, growth hormone
  • Thyroid hormone, catecholamines
  • Hypopituitarism
20
Q

What causes hypoglycemia in sepsis (3):

describe MoA or non–insulin-mediated increased consumption:

Do bacT use BG in sepsis:

beyond sepsis, infectious dz specifically associated with hypoglycemia:

A
  • decreased intake
  • decreased hepatic function
  • most significantly, non–insulin-mediated increased consumption

1- inflammatory mediators: TNF-a, especially
in macrophage-rich tissues such as the spleen, liver, and lungs = > BG consumption
2. hypotension or hypoxemia induce excess BG consumption via increases in anaerobic glycolysis

not mentioned

Canine babesiosis
& hypoglycemia at admission is a poor px indicator
2 to same MoA as bacterial sepsis or by consumption of glucose by the parasites

21
Q

insulinoma dextrose tx NO why?

Glucagon CRI

GC:

A

increases insulin secretion

hyperinsulinemia has been shown to depress glucagon
removing one of the counterregulatory mechanisms vital to maintaining euglycemia

lowest rate necessary to eliminate CS

antagonize insulin