Hypoglycemia Flashcards
Hypoglycemia occurs via one of several mechanisms:
- excess insulin or insulin analogs
- excessive glucose utilization, and
- decreased glucose production
most common specific causes of hypoglycemia:
excess insulin:
excess utilization:
decreased production:
exogenous insulin overdose
insulinoma
other insulin analog–secreting tumors
sepsis
hypoglycemia of puppies and toy
hypoadrenocorticism
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:
low energy
adrenergic stimulation = restlessness, anxiety, tachypnea, vomiting or diarrhea, and trembling
insulinoma or insulin analog–secreting
neoplasms
gluconeogenesis is what:
production of glucose from precursors lactate (ketone to acytl-coA), pyruvate, amino acids, and glycerol
β cells - insulin, secreted in response to (3):
GI hormones:
glucose
amino acids
GI hormones:
gastrin
secretin
cholecystokinin
gastric inhibitory peptide
Glucagon MoA 4):
directly stimulates hepatic glycogenolysis
gluconeogenesis
mobilizes gluconeogenic precursors
reduces peripheral glucose utilization
Growth hormone antagonizes effects of insulin by:
decreasing peripheral glucose utilization
promoting lipolysis
neuroglycopenia:
Brain obligate energy source:
relies on a constant stream of glucose for its energy needs, enters via:
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
How can some animals, especially those with prolonged hypoglycemia, demonstrate no associated CS:
upregulate cerebral glucose uptake
def hypoglycemia #:
Whipple’s triad provides guidelines for identifying hypoglycemia:
< 60, <50mg/dl CS
CS, low BG, abatement of CS with dextrose
Exogenous insulin overdose - duration of affect:
ddx cat DM low BG:
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
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:
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
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:
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
dx: insulin:glucose ratio
Abdominal ultrasonography:
CT, MRI, scintigraphy, sx exploration:
CXR to look for
may or may not reveal a mass
other options for attempted identification insulinoma
mets
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:
- glucagon CRI
- 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
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
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
other ddx hypoglycemia
Artifact (3)*:
Excess Insulin
Insulin Analogs (6):
Artifact*
- Pseudohypoglycemia* (serum sat, RBC used BG)
- Handheld glucometer*
- 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
Toxins and medications (2) MoA
Excess Glucose Utilization
Exercise-induced (hunting dog) hypoglycemia
Decreased Glucose Production (3)
how much of liver must fail?
• 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
- Neonatal hypoglycemia/toy breed
- Hepatic dysfunction (70%)
• Portosystemic shunt
• Inflammatory or infectious hepatitis
• Hepatic lipidosis
• Cirrhosis
• Neoplasia
• Glycogen storage disease - Hypocortisolism
Counterregulatory hormone deficiencies
B-blockers
Paraneoplastic
Polycythemia
Leukocytosis
Pregnancy
- Glucagon, growth hormone
- Thyroid hormone, catecholamines
- Hypopituitarism
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:
- 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
insulinoma dextrose tx NO why?
Glucagon CRI
GC:
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
