Hypoglycaemia ✅ Flashcards
What history features should you pay attention to when evaluating a child with hypoglycaemia?
- Autonomic symptoms
- Neuroglycopenic symptoms
- Pregnancy details (in neonate)
- Relationship of symptoms to feeding
- Access to oral hypoglycaemic medication
- Family history of sudden infant death or consanguinity
- Development of symptoms in response to certain foods
What are the autonomic symptoms of hypoglycaemia in a neonate?
- Pallor
- Sweating
- Tachypnoea
What are the autonomic symptoms of hypoglycaemia in an older child?
- Palpitations
- Tremor
What are the neuroglycopenic symptoms of hypoglycaemia in a neonate?
- Jitteriness
- Apnoea
- Hypotonia
- Feeding problems
- Irritability
- Abnormal cry
- Convulsions
- Coma
What are the neuroglycopenic symptoms of hypoglycaemia in older children?
- Hunger
- Abdominal pain
- Nausea and vomiting
- Pins and needles
- Headache
- Weakness
- Dizziness
- Blurred vision
- Irritability
- Mental confusion
- Odd behaviour
- Fainting
- Convulsions
- Coma
What pregnancy details should be considered when evaluating a neonate with hypoglycaemia?
- Maternal symptoms of diabetes
- Breech?
- Birth weight
Why is it important to know if a neonate was breech in hypoglycaemia?
Breech said to be more common in hypopituitarism
Why is it important to know the birth weight of a neonate with hypoglycaemia?
Hypoglycaemia more common in IUGR or large for gestational age due to maternal diabetes
Why is it important to know the relationship of symptoms to hypoglycaemia?
Can help determine if due to inadequate fuel supply or excess fuel requirements, e.g. hyperinsulinism
Why is it important to know about access to oral hypoglycaemic medications?
May have been accidentally ingested
Why is it important to know about family history of SIDS or consanguinity?
Might suggest an inborn error of metabolism
What foods should you ask about symptom development in response to?
Foods containing lactose, fructose, or sucrose
What might symptom development in response to lactose, fructose, or sucrose suggest in hypoglycaemia?
Inborn errors in metabolism
What is usually found on examination in hypoglycaemia?
Most children with a history of hypoglycaemia will not have any abnormal clinical signs unless hypoglycaemic at the time
Why is it important to look for clinical signs on examination in hypoglycaemia?
May indicate associated diagnosis
What might suggest septo-optic dysplasia?
Optic atrophy
What is septo-optic dysplasia?
A rare congenital malformation syndrome featuring;
- Underdevelopment of the optic nerve
- Pituitary gland dysfunction
- Absence of the septum pellucidum (a midline part of the brain)
What might suggest hypopituitarism?
- Cranial midline defects
- Short stature
- Microgenitalia
What might suggest Addison’s disease?
- Increased skin or buccal pigmentation
- Hypotension
What might suggest accelerated starvation?
Underweight or signs of malnutrition
What might suggest hyperinsulinism?
- Tall stature
- Excess weight
What might suggest Beckwith-Wiedemann syndrome?
- Abnormal ear lobe creases
- Macroglossia
- Umbilical hernia
- Hemihypertrophy
What might suggest a glycogen storage disorder?
Hepatosplenomegaly
What is the aim of investigations in hypoglycaemia?
- Establish severity
- Evaluate counter-regulatory responses and intermediary metabolite pathways
How is hypoglycaemia investigated?
Obtaining blood sample prior to treatment
What might be looked for on blood tests in hypoglycaemia?
- Glucose
- U&Es
- Bicarb and pH
- LFTs
- Ammonia
- Insulin and c-peptide
- Cortical, ACTH, and growth hormone
- Free fatty acids and beta-hydroxybutyrate
- Acylcarnitine
- Lactate
- Alanine
Why is glucose checked in hypoglycaemia?
Confirm severity
Why are U&Es done in hypoglycaemia?
Look for evidence of adrenal insufficiency
Why are bicarb and pH checked in hypoglycaemia?
Acidosis might imply adrenal failure or inborn error of metabolism
Why should LFTs be done in hypoglycaemia?
May be abnormal in;
- Primary liver disease
- Sepsis
- Glycogen storage disease
- Galactosaemia
- Fatty acid oxidation defects
- Hereditary fructose intolerance
What can ammonia show in hypoglycaemia?
Can be raised in a number of inborn errors of metabolism and some forms of hyperinsulinism
What should happen to insulin and c-peptide in hypoglycaemia?
Should be suppressed
What should happen to cortisol, ACTH, and GH in hypoglycaemia?
Should normally be elevated (implying appropriate stress response)
What can free fatty acids and beta-hydroxybutyrate show in hypoglycaemia?
If elevated in proportion, imply lipolysis
What can acylcarnitine show in hypoglycaemia?
Abnormal in some fatty acid oxidation defects
What can lactate show in hypoglycaemia?
Elevated in;
- Metabolic liver disease
- Glycogen storage disorder
- Sepsis
What can alanine show in hypoglycaemia?
If low, suggests accelerated starvation
What investigation should be done after glucose has been administered to correct the hypoglycaemia?
The next urine sample should be collected
What testing is done on the urine sample in hypoglycaemia?
- Screen for inborn errors of metabolism
- Toxicology screen
What is looked for on a urine screen for inborn errors of metabolism?
- Ketones
- Reducing sugars
- Dicarboxylic acids
- Glycine conjugates
- Carnitine derivatives
- Amino acids
- Organic acids
What does the treatment of hypoglycaemia depend on?
Aetiology
What can the causes of hypoglycaemia be broadly subdivided into?
- Causes associated with reduced glucose availability due to detects in counter-regulatory responses (including limited supplies of glucose precursors)
- Increased glucose consumption
What causes of hypoglycaemia are due to reduced glucose availability?
- IUGR
- Prematurity
- Hypopituitarism
- Adrenal insufficiency
- GH deficiency
- Hypothyroidism
- Accelerated starvation
- Glucagon deficiency
- Inborn errors of metabolism
- Drugs
- Liver dysfunction
- Congenital heart disease
What drugs can cause hypoglycaemia due to reduced glucose availability?
- Alcohol
- Aspirin
- Beta blockers
What does investigation of hypoglycaemia often find when the cause is reduced glucose availability?
Frequently fails to demonstrate any underlying abnormality
When can accelerated starvation be diagnosed?
Only once other endocrine and metabolic causes are excluded
What is accelerated starvation characterised by?
Normal endocrine counter-regulatory response with raised fatty acid and ketone responses
What are the risk factors for accelerated starvation?
- Boys
- Small for gestational age or thin physique
What normally happens to accelerated starvation with time?
Usually resolves by puberty
What does treatment of acceleration starvation involve?
- Avoidance of prolonged fasting, particularly during illness
- Administration of complex carbohydrates prior to bed
- IV dextrose as required to reverse acute hypoglycaemia
What are the causes of hypoglycaemia caused by increased glucose consumption?
- Congenital hyperinsulinism
- Transient neonatal hyperinsulinism
- Infant to diabetic mother
- Insulinoma
- Beckwith-Wiedemann syndrome
- Rhesus haemolytic disease
- Perinatal asphyxia
- Malaria
What suggests hyperinsulinism?
Markedly excessive glucose requirements e.g. 12mg/kg/hour + to avoid hypoglycaemia
What might congenital hyperinsulinism occur in relation to?
Several genetic defects affecting the regulation of insulin release
What are the most commonly identified genetic defects in congenital hyperinsulinism?
- ABCC8
- KCNJ11
What does ABCC8 encode?
The sulphonylurea receptor
What does KCNJ11 encode?
Potassium inward rectifying channel
What are children affected by congenital hyperinsulinism at increased risk of?
Hypoglycaemia-induced brain damage
Why are children with congenital hyperinsulinism at increased risk of hypoglycaemia-induced brain damage?
Hyperinsulinism suppresses not only glucose, but also ketone body production, which is an alternative cerebral fuel source
What is the first line management for congenital hyperinsulinism?
Diazoxide and chlorothiazide treatment
How does diazoxide evert its effects in congenital hyperinsulinism?
Through actions on the potassium channel, by;
- Inducing hyperpolarisation
- Decreasing calcium influx
- Reducing insulin secretion
What is second line management for congenital hyperinsulinism?
Somatostatin analogues
How do somatostatin analogues work in congenital hyperinsulinism?
They exert a direct receptor-mediated inhibition of insulin release
What are the surgical options for persistent cases of congenital hyperinsulinism?
Surgical excision of part of pancreas
What has allowed for the technique of surgical excision of part of the pancreas in congenital hyperinsulinism?
Advances in understanding of genetics and new imaging techniques such as [18F]DOPA-PET scanning, which allows distinction between focal and diffuse pancreatic disease, with the former being curable by surgical excision with minimal morbidity
