Hypoglycaemia + Glucose homeostasis Flashcards
What are the three main sources of glucose in the body?
- Intestinal absorption from digestion of carbohydrates
- Glycogenolysis
- Gluconeogenesis
What hormones are involved in the regulation of blood glucose levels?
Insulin, glucagon, cortisol, growth hormone, epinephrine
List the general mechanisms that can lead to hypoglycaemia.
- Inadequate dietary intake
- Excessive glucose utilisation
- Dysfunctional glycogenolysis or gluconeogenesis
- Endocrine abnormalities
What are common clinical signs of hypoglycaemia?
Cerebral dysfunction, behavioural changes, muscular weakness, ataxia, collapse, altered vision, seizures, stupor, coma
True or False: The brain has significant glycogen stores.
False
Brain has obligatory need for glucose to produce ATP
IE so many of the clin signs are neurological
What is neuroglycopenia?
Hypoglycaemia of the central nervous system
What can result from severe and prolonged hypoglycaemia?
Neuronal cell death, permanent brain injury, neurologic signs such as blindness
What is the definition of hypoglycaemia in terms of blood glucose concentration?
A blood glucose concentration of 3.5 mmol/L or less
What is Whipple’s triad used for?
Identification of hypoglycaemia
List the components of Whipple’s triad.
- Presence of clinical signs of hypoglycaemia
- Documented low blood glucose concentration
- Abatement of clinical signs with correction of hypoglycaemia
What factors can affect blood glucose measurements?
Type of blood used (arterial, venous, capillary), method of measurement
What is the typical difference in glucose concentration between plasma and whole blood?
Plasma usually 12 - 13% higher due to water content. Also why glucose measured on whole blood will be lower in haemoconcentrated animals.
What are the three main categories of causes for hypoglycaemia?
- Excessive insulin or insulin analogues
- Excessive glucose utilisation
- Decreased glucose production
Give an example of a cause of excessive insulin leading to hypoglycaemia.
Exogenous insulin overdose
What is a common cause of excessive glucose utilisation in veterinary patients?
Infection, such as sepsis or babesiosis
Why are neonate predisposed to hypoglycaemia
- easily depleted hepatic glycogen stores especailly when intake is low.
- immature enzyme systems for gluconeogenesis
- large contribution of the brain to metabolic rate
- (causes: infection, vaccination, GI signs, nutrition/fasting and hypothermia)
What is the significance of monitoring blood glucose in patients after an insulin overdose?
To determine the need for supplemental dextrose and insulin therapy
What should be considered if a patient has ongoing hypoglycaemia after an insulin overdose?
Additional underlying problems that predispose to hypoglycaemia
What is the prognosis for animals recovering from neuroglycopenia due to insulin overdose?
Most animals show significant improvement in clinical signs within 12 hours of presentation and treatment
lasting longer than 12 hours guarded
What are insulinomas?
Insulinomas are insulin-secreting tumours of the islet cells of the pancreas that are usually malignant.
What symptoms do patients with insulinomas typically exhibit?
Patients often show weakness and collapse, with severe hypoglycaemia being an isolated and unexpected finding.
What diagnostic method is used to confirm insulinoma during hypoglycaemia?
Evaluating endogenous blood insulin levels at the time of hypoglycaemia.
What does a high or normal insulin level in the face of hypoglycaemia indicate?
It is indicative of insulinoma.
What imaging techniques can be used to locate an insulinoma?
Abdominal ultrasound, computed tomography, and surgical exploration.
What is paraneoplastic hypoglycaemia?
Hypoglycaemia that may result from any tumour type, commonly due to secretion of insulin or insulin-analogues, increased glucose consumption by tumour cells, or failure of glycogenolysis or gluconeogenesis.
What may cause hypoglycaemia in cases of severe liver disease?
Decreased glycogenolysis and gluconeogenesis, in addition to dysfunctional glycogen storage.
What are common clinical signs of severe liver disease in dogs?
Icterus, poor body condition score, ascites, vomiting, diarrhoea, and signs of hepatic encephalopathy.
What is the most common cause of hypoglycaemia associated with infection?
Sepsis, usually bacterial.
What role does exercise play in hypoglycaemia for hunting dogs?
Exercise-induced hypoglycaemia occurs due to massive increases in glucose utilization by muscular activity.
feed frequent small meals if recurs retire
What is the effect of seizures on blood glucose levels?
Massive muscular glucose consumption during severe prolonged seizures may result in hypoglycaemia.
What can hypocortisolism cause in terms of blood glucose levels?
It can lead to hypoglycaemia due to loss of the counter-regulatory hormone cortisol.
addisons
What initial treatment is recommended for a hypoglycaemic crisis?
Intravenous dextrose.
1ml/kg diluted in 2 - 4 parts saline
What should be done if intravenous access is not available during a hypoglycaemic crisis?
Intraosseous delivery may be considered.
What is the recommended bolus of dextrose for treating hypoglycaemia?
1 ml/kg of a 50% dextrose solution.
What is a potential complication of administering intravenous dextrose to a patient with insulinoma?
It may stimulate the release of additional insulin, causing rebound hypoglycaemia.
Chronic hyperinsulinaemia can surpress glucagon production
What hormones can be used to counteract the effects of insulin in hypoglycaemia?
Glucocorticoids (such as dexamethasone) and glucagon.
if giving corticosteroids to a patient with insulinoma try to be sure of the diagnosis - no contraindications such as sepsis or lymphoma
What is a contraindication for glucose administration in a patient experiencing seizures?
Glucose administration is contraindicated in non-hypoglycaemic patients due to the risk of hyperglycaemia exacerbating neuronal damage.
need to investigate if hypoglycaemia was the cause or effect of seizuring
What are some differentials for hypoglycaemia due to excessive insulin or insulin analogues
overdose, insulinoma, paraneoplastic, xylitol
What are some differentials for hypoglycaemia due to excessive glucose utilisation
-infection, sepsis
- excercise or seizure
- paraneoplastic
- polycythemia
- anaphylaxis
What are some differentials for hypoglycaemia due to decreased glucose production
- neonatal or toy breed
- hepatic failure
- addisons (low cortisol)
- deficiency of counter regulatory hormones
- betablockers
