Endocrine System & Assessment

What the system does

• A network of glands releasing hormones into the blood
• Hormones travel to distant target organs/cells
• Controls growth, metabolism, reproduction, stress response
• Works alongside the nervous system, but acts more slowly

Major glands

• Pituitary: the "master gland", controls other glands
• Thyroid: sets metabolic rate
• Adrenal glands: cortisol, adrenaline, stress response
• Pancreas: insulin and glucagon, blood glucose control

Negative feedback

• Most hormone levels are self-correcting
• Hormone rises → triggers a response → hormone falls back
• Example: high blood glucose → insulin released → glucose falls
• This is the same feedback-loop pattern used everywhere in physiology

Why it matters clinically

• Endocrine problems are often "too much" or "too little" hormone
• Signs are usually widespread, not localised to one organ
• Many conditions are lifelong and need ongoing monitoring
• Small dose/timing errors in replacement hormones can matter a lot

Normal control

• Insulin (beta cells): lowers blood glucose, lets it into cells
• Glucagon (alpha cells): raises blood glucose from stores
• The two work as a push-pull pair around a set point
• Both are released by the pancreas, an endocrine and digestive organ

Type 1 diabetes

• Autoimmune destruction of insulin-producing beta cells
• Little or no insulin produced at all
• Usually presents in childhood/young adulthood
• Always needs insulin replacement – the body cannot make its own

Type 2 diabetes

• Insulin resistance ± reduced insulin production over time
• Strongly linked to weight, activity, and genetics
• Usually develops gradually in adulthood
• May be managed with lifestyle change, tablets, and/or insulin

Why the distinction matters

• Type 1 can never be managed on diet/tablets alone
• Missing insulin in type 1 risks DKA far faster than in type 2
• Type 2 has a much wider range of first-line treatments
• Both need patient education on hypo/hyperglycaemia recognition

What the thyroid does

• Produces T3/T4, which set the body’s metabolic rate
• Affects heart rate, temperature, energy, growth, and mood
• Controlled by TSH from the pituitary (another feedback loop)

Hypothyroidism (underactive)

• Fatigue, weight gain, cold intolerance, slow heart rate
• Dry skin, constipation, low mood
• In children: can affect growth and development if untreated

Hyperthyroidism (overactive)

• Weight loss, heat intolerance, fast heart rate, tremor
• Anxiety, sweating, difficulty sleeping
• Graves’ disease is a common autoimmune cause

Growth hormone in children

• Growth hormone (pituitary) drives height and tissue growth
• Deficiency: short stature, slow growth velocity
• Growth charts and growth velocity matter more than one measurement

What the adrenals do

• Cortisol: the body’s main stress hormone, affects glucose/immunity
• Aldosterone: controls sodium/potassium and fluid balance
• Adrenaline/noradrenaline: fight-or-flight response

Addison’s disease (too little)

• Adrenal cortex cannot make enough cortisol/aldosterone
• Fatigue, weight loss, low BP, salt craving, skin darkening
• An adrenal (Addisonian) crisis is a life-threatening emergency

Cushing’s syndrome (too much)

• Excess cortisol, often from long-term steroid medication
• Weight gain (central), thin skin, easy bruising, high BP
• Can also come from a pituitary or adrenal tumour

Why steroid medication matters

• Long-term steroids suppress the body’s own cortisol production
• Stopping steroids suddenly can trigger an adrenal crisis
• Steroid doses are often reduced gradually ("weaned"), not stopped abruptly
• Patients on long-term steroids carry a steroid alert card for this reason

Diabetic ketoacidosis (DKA)

• Lack of insulin → body burns fat for fuel → ketones build up
• High blood glucose, ketones, and acidosis together
• Deep, rapid breathing (Kussmaul breathing), sweet/pear-drop breath
• Can develop faster and more severely in children than adults

DKA triggers

• Missed or insufficient insulin doses
• Infection, illness, or physical stress increasing insulin need
• Can be the first presentation of previously undiagnosed diabetes

Hypoglycaemia (low glucose)

• Too much insulin relative to glucose intake/activity
• Shaking, sweating, hunger, confusion, irritability
• Severe: reduced consciousness, seizures – needs urgent treatment

Why speed matters

• DKA and severe hypoglycaemia can both be life-threatening
• They need opposite corrections – mixing them up is dangerous
• Blood glucose ± ketone testing is what actually tells them apart
• Always check glucose in any unexplained confusion in a known diabetic

Bedside checks

• Blood glucose (capillary) – quick, repeatable, essential
• Ketones (blood or urine) when DKA is suspected
• Vital signs: HR, RR, BP, temperature, consciousness
• Weight trend – useful in both diabetes and thyroid disease

Paediatric considerations

• Children can decompensate into DKA faster than adults
• Growth and development are extra vitals to track over time
• Insulin doses are weight-based and reviewed often as children grow
• Family/carer education is central to day-to-day management

Adult considerations

• Type 2 diabetes often coexists with cardiovascular risk factors
• Long-term steroid use is common – always check for it
• Older adults may have atypical or subtle hypo symptoms
• Polypharmacy increases the chance of drug interactions

Escalation triggers

• Any suspected DKA – this needs urgent medical review
• Severe hypoglycaemia not responding to initial treatment
• Signs of adrenal or thyroid crisis
• New confusion in anyone with known endocrine disease