Tuesday, 31 October 2017

Adrenal Crisis


Anterior pituitary - ACTH, GH, FSH, LH, TSH, PRL




Posterior pituitary- ADH, oxytocin

Presentation
History of recent physical stress like stress, major injury, myocardial infarction 
Nausea and vomiting, muscle pains, confusion, coma, fatigue
Low BP or postural hypotension, tachycardia
Risk if ≥5 mg prednisolone equivalent for more than 4 weeks

Investigations
Hypoglycaemia
Low sodium
High potassium 
A patient with hypothyroidism feels worse on thyroxine
T1 DM with unexplained hypoglycaemia
Hyperuraemia
Hypercalcaemia
Metabolic acidosis
Random 9am cortisol  or short synacthen test - helps differentiate between primary and secondary adrenal insufficiency. 
Raised thyroid stimulating hormone (TSH)

Pathophysiology
Primary - disease affecting the adrenal gland  Addison's 
  Autoimmune 
  Infective (including TB, HIV and fungal) 
  Iatrogenic
  Haemorrhage or infarction (Waterhouse- Friedrichsen- meningococcemia)
  Malignant infiltration (metastasis, lymphoma) 
  Non malignant infiltration (sarcoidosis, haemochromatosis, amyloidosis)
  Genetic 

Secondary/Tertiary adrenal insufficiency (twice as common as addisons)
Panhypopituitarism
Pituitary apoplexy – infarction or hemorrhage of tumor
Chronic steroid therapy (suppresses HPA axis)
Tumors, granulomas

Treatment
1L/hour to maintain their BP
Hydrocortisone 100 mg with subsequent doses of 100 to 200 mg over 24 hours divided into three or four doses.
Look for and treat trigger 

Sick Day Rules
Double hydrocortisone if fever > 37.5 C or for infection or sepsis requiring an antibiotic
For severe nausea (often with a headache), 20 mg of hydrocortisone orally and sip rehydration or electrolyte fluids (such as dioralyte)
On vomiting, they should use their emergency injection if they have one (eg 100 mg of hydrocortisone) immediately. Then they should call a doctor, saying ‘Addison’s emergency’
They should take 20 mg of hydrocortisone orally immediately after a major injury to avoid shock
If patients have persistent vomiting or diarrhoea that is likely to interfere with absorption of medication or fluid balance, you should admit them to hospital for intravenous hydrocortisone

Some authors recommend that the dose of hydrocortisone should be increased (by 5 mg to 10 mg) before strenuous exercise.


Pituitary Apoplexy

Acute haemorrhagic or non-haemorrhagic necrosis of the pituitary gland. An existing pituitary macroadenoma is usually present (60-90%) but it can occur with healthy glands in few isolated cases. It is also more likely with medical treatment of a prolactinoma, pregnancy (Sheehan) and cerebral angiography, trauma and sudden changes in ICP.  
As the gland suddenly enlarges it may cause compression of structures adjacent to the sella leading to: 
  sudden headache
  loss of visual acuity with a chiasmal field defect
  oculomotor palsies (CN III) 
  Decreased level of consciousness, hypopituitanism, Addisonian crisis and subarachnoid irritation. 

Investigation
CT -  routine CT is insensitive to the diagnosis unless frank intracranial haemorrhage is present. The pituitary mass may be evident and be hyperdense. Fluid debris levels may also be evident. Useful to do to exclude a sub-arachnoid. 

MRI - typically demonstrates a pituitary region mass. Confirms the diagnosis in over 90% of patients. A pituitary CT is indicated if MRI is contraindicated or not possible.

Endocrine evaluation with blood samples for random serum cortisol, TSH, free T4, prolactin, IGF1, LH, FSH, testosterone (men), oestradiol (women) for later analysis
Hyponatraemia in 40% of cases 

Treatment
Hydrocortisone 100 mg i.m. bolus followed by 50–100 mg six hourly by intramuscular injection or 100–200 mg as an intravenous bolus followed by 2–4 mg per hour by continuous i.v. infusion can be used

Neurosurgical intervention should be considered in patients with:
   Severely reduced visual acuity
   Severe and persistent visual field defects
   Deteriorating level of consciousness

References 
https://lifeinthefastlane.com/ccc/adrenal-insufficency/

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