felis - Articles
Hypoglycemia
Synonym(s): Hypoglycaemia, hypo
Introduction
- Plasma glucose less than 3.0 mmol/L (55 mg/dL) is significant.
- In animals that have chronic low blood glucose concentrations may have to drop very low (less than 2.0 mmol/L (35 mg/dL)) before clinical signs are exhibited.
- Signs: ataxia, weakness, disorientation, seizures.
- Diagnosis: blood or plasma glucose concentration.
- Treatment: glucose (oral or intravenous), and correct underlying cause. Note that consumption of food will not reliably increase blood glucose in cats.
Presenting signs
- Weakness/collapse.
- Ataxia/incoordination.
- Lethargy/sleepiness.
- Trembling/muscle tremors.
- Anxiety/behavioral changes/yowling/bed wetting.
- Disorientation/confusion/apparent blindness.
- Vomiting.
- Collapse with or without loss of consciousness.
- Seizures.
- Other neurological signs.
- Polyphagia.
Acute presentation
- Often present after collapse or seizure.
- Signs may be acute or intermittent/episodic.
- Diabetic cats receiving insulin treatment.
Age predisposition
- Neonate.
- Middle-aged and senior.
Special risks
- General anesthesia/surgical procedures - hypoglycemia must be controlled, eg with continuous IV glucose infusions.
Pathogenesis
Etiology
Physiological
- Neonatal hypoglycemia - dystocia, hypothermia, hypoxia, failure to feed/maternal rejection/maternal agalactia, dehydration, diarrhea may be contributing causes.
- Anorexia/malnourishment - especially in neonate/juvenile cats.
Primary disease
- Liver disease, particularly large hepatomas Liver: primary hepatic neoplasia.
- Renal failure Kidney: chronic kidney disease.
- Sepsis - 'bacterial shock' Shock: septic.
- Adrenocortical insufficiency Hypoadrenocorticism.
- Functional islet cell tumor (insulinoma Insulinoma).
- Extrapancreatic neoplasia (such as lymphoma).
- Non-neoplastic beta cell hyperplasia (acquired nesidioblastosis).
Exogenous agents
- Excessive insulin dosage during treatment for Diabetes mellitus Diabetes mellitus.
- Oral hypoglycemic agents Oral hypoglycemic agents during treatment for Diabetes mellitus.
- Drug ingestion, eg ethanol Ethanol, propranolol Propranolol, salicylates Acetyl salicylic acid.
Predisposing factors
General
- Neonatal/juvenile animals have immature mechanisms for regulating blood glucose.
- Cold, other stresses.
- Treatment of Diabetes mellitus Diabetes mellitus: management regimens.
Pathophysiology
- Decrease of blood glucose towards the lower end of the physiological range stimulates secretion of counter-regulatory hormones (glucagon, adrenaline, noradrenaline, cortisol and growth hormone), which increase glycogenolysis and gluconeogenesis and so increase blood glucose concentration.
- Hypoglycemia results from failure of these mechanisms due to excess insulin, deficiency of counter-regulatory hormones, and/or inadequate glucose production.
- Hypoglycemia also → an increased appetite.
- If these protective counter-regulatory mechanisms are overwhelmed, hypoglycemia → reduced glucose availability to central and peripheral nervous system → lethargy, weakness, ataxia, disorientation, seizures.
- Prolonged severe hypoglycemia → reversible or irreversible brain damage, and rarely death.
Specific
- Neonatal hypoglycemia - gluconeogenesis limited in neonate and limited glycogen stores rapidly deplete - relies upon regular feeding - may develop hypoglycemia after only 12 hour fast.
- Starvation - severe malnutrition → decreased hepatic glycogen, decreased fat stores → decreased gluconeogenesis → hypoglycemia.
- Exogenous agents: direct drug action → hypoglycemia.
- Bacterial shock → depletion of glycogen stores, increased peripheral use of glucose, decreased gluconeogenesis + ?circulatory factors → hypoglycemia.
- Extra-pancreatic tumors:
- Secretion of Insulin/insulin-like/insulin precursor.
- Accelerated glucose utilization.
- Inhibited glucose release from liver → hypoglycemia.
- Functional islet cell tumor or non-neoplastic beta cell hyperplasia → insulin secretion → hypoglycemia.
- Insulin overdose, inappetence/starvation, and/or concurrent illness during treatment with insulin may → hypoglycemia.
Diagnosis
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Treatment
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Prevention
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Outcomes
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Behrend E, Holford A, Lathan P et al (2018) 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. JAAHA 54 (1), 1-21 PubMed.
- Viebrock K A, Dennis J (2017) Hypoglycemia episodes in cats with diabetes mellitus: 30 cases (2013-2015). J Feline Med Surg 20 (6), 563-70 PubMed.
- Hambrook L E, Ciavarella A A, Nimmo J S et al (2016) Hyperinsulinaemic, hypoglycaemic syndrome due to acquired nesidioblastosis in a cat. JSFM Open Rep 2 (2), 2055116916657846 PubMed.
- Greene S N, Bright R M (2008) Insulinoma in a cat. JSAP 49 (1), 38-40 PubMed.
- Münnich A (2008) The pathological newborn in small animals: the neonate is not a small adult. Vet Res Commun 32 (Suppl 1), S81-5 PubMed.
- Gabor L J, Canfield P J, Malik R (2000) Haematological and biochemical findings in cats in Austrlia with lymphosaroma. Aust Vet J 78 (7), 456-461 PubMed.