Endocrine emergencies Flashcards
What are the causes of thyrotoxicosis
Different part of the thyroid axis:
- Thyroid problems:
- Autoimmune (Grave’s, Hashimoto’s)
- Tumours (benign adenoma, multinodular goitre, malignancy)
- Drug causes (iodine, lithium, amiodarone) - Pituitary problems:
- TSH secreting adenoma - External to the axis:
- exogenous thyroid hormone excess
- metastatic follicular carcinoma
- molar pregnancy/ovarian teratoma
What functions does the thyroid gland perform?
Exocrine hormone gland producing:
- T3
- T4
- Calcitonin
T3&T4 are produced from the follicular cells and are regulated by a negative feedback control via the pituitary gland.
They maintain metabolic rate, temperature regulation and important in growth.
Calcitonin is released from C-cells and plays a role in calcium homeostasis and bone metabolism.
What are the changes that occur in thyroid hormones in the critically ill?
Fairly normal to develop a sick euthyroid picture (low T3 and T4 with low or normal TSH) in critical illness.
What is thyrotoxicosis?
Supra-normal serum levels of T3 and/or T4 with clinical features of end organ effects:
- agitation
- tachycardia
- intolerance of heat
- gastrointestinal upset e.g. loose/frequent stools
What is thyroid storm and how does it differ from thyrotoxicosis?
Thyroid storm is a severe clinical presentation of thyrotoxicosis.
- Biochemically it may not be markedly different
- Clinical features include:
i) Pyrexia >38.5
ii) Profuse sweating
iii) Tachyarrhythmias
iv) heart failure
v) organ dysfunction (renal, hepatic, CNS)
May be difficult to distinguish from sepsis or other hypermetabolic states unless high index of suspicion.
What are the risk factors or precipitants of thyroid storm?
- Surgery (inc. thyroid surgery)
- Anaesthesia
- Trauma
- Burns
- Pregnancy
- Infection
- Drugs - Iodinated compounds (contrast, amiodraone)
- Thyroiditis
- DKA
What is the management of thyroid storm?
Resuscitate the patient in an ABCDE approach correcting abnormalities as you find them.
Specific features include:
- Mx precipitating illness:
- septic screen and Abx
- checking pregnancy
- T3, T4, TSH levels
- calcium, glucose, transaminases - Inhibition of thyroid hormones release:
- propylthiouracil, carbimazole - Inhibit conversion of T4 to T3:
- propylthiouracil
- corticosteroids
- Lugol’s iodine - Supportive care:
- fluid resuscitation
- cooling measures
- sedation and intubation for agitation/CNS involvement
- propranolol
- corticosteroids
What is adrenal insufficiency?
Inappropriately low levels of cortisol +/- mineralocorticoid
Can be:
Primary (decreased adrenal gland secretion)
- Addison’s disease
Secondary (decreased pituitary ACTH)
- Tertiary (decreased hypothalamic CRH)
What is Addison’s disease?
Primary adrenal failure.
Causes:
- Autoimmune
- Infection (TB globally)
- Surgery
- Malignancy
- Drugs: Etomidate
How is adrenal insufficiency diagnosed?
- Cortisol and ACTH levels
- Primary (ACTH high, cortisol low)
- Secondary and tertiary (Cortisol low, ACTH low) - Synacthen test
- cortisol levels are checked before and after (30mins) synthetic ACTH injection
- not affected by dexamethasone
- negative rules out primary, but not 2 or 3. - Adrenal antibodies
- Radiological investigation
- Pituitary screen
How might Addisonian crisis present?
CVS: - Distributive shock
Neuro - Lethargy, fatigue, weakness, confusion
GI: abdo pain, GI upset
Skin: Hyperpigmentation
Biochemistry: Hyponatraemia, hyperkalaemia, hypoglycaemia, metabolic acidosis
Other AI diseases: pernicious anaemia, Grave’s disease, diabetes.
How would you manage a patient with Addisonian crisis?
Resuscitate in ABCDE approach correcting abnormalities as you find them.
- Fluid resuscitation and correction of hypoglycaemia
- Send baseline cortisol, glucose and ACTH bloods
- May require 200mg hydrocortisone therapy (can use dexamethasone instead if not in extremis)
- Level 2/3 care
- Identify and treat precipitant.
- Endocrine involvement.
What rate of correction would you aim for in management of DKA?
Blood glucose: Reduction by 3mmol/L/hr
Blood ketones: Reduction by 0.5mmol/L/hr
Bicarbonate: Increase of 3mmol/L/hr
