Addisons Disease (Chronic Adrenal Insufficiency)

Last updated 08.03.13

 

Index

 

Definition

-  Chronic deficiency of adreal cortisol +/- aldosterone

 

Features

-  Rare endocrine disorder

-  Incidence 1:100,000

-  Occurs all age groups

-  Men = women

-  Primary adrenal insufficiency

-  Adrenal gland pathology

-  Adrenal insufficiency when 90% of gland destroyed

-  Deficiency of cortisol +/- aldosterone

-  Secondary adrenal insufficiency

-  Pituitary &/or hypothalamic pathology

-  Insufficient ACTH

-  Deficiency of cortisol (aldosterone not effected)

-  Difficult to diagnose initially

 

Causes

-  Primary

-  Autoimmune destruction of adrenal cortex

-   Most common cause (70% pts)

-  Idiopathic adrenal insufficiency

-  Polyendocrine deficiency syndrome (Type 1 & 2)

-  TB

-   20% cases of primary adrenal insufficiency

-  Chronic infections (fungal..)

-  Metastatic spread

-  Amyloidosis

-  Adrenalectomy

-  Secondary

-  Cessation of exogenous corticosteroids

-  Pituitary surgery (Cushings disease)

-  Pituitary tumours

-  Pituitary infections

-  Pituitary radiotherapy

-  Sheehans syndrome

 

Associated S/S

-  Usually insidious

-  Weight loss

-  +/- anorexia

-  Nausea, vomiting, diarrhoea in 50% pts

-  Craving of salty foods (secondary to salt loss)

-  Muscle weakness

-  Fatigue

-  Chronic & worsening

-  Hypotension

-  Postural Hypotension

-  Dizziness

-  Syncope

-  Hyperpigmentation of skin

-  Most visible on scars, skin folds, pressure bearing surfaces, lips & mucous membranes

-  Irritability, depression

-  Irregular mentruation

-  Addisonian Crisis

-  25% pts first presentation of S/S

-  Sudden penetrating lower back, abdo or leg pain

-  Severe vomiting or diarrhoea

-  Dehydration, hypotension

-  Can be fatal if left untreated

-  Other AID: thyroid disease, DM Type 1

 

Ix

-  BSL

-  Hypoglycaemia (more common in children)

-  BP

-  Postural BP

-  U&E

-  Hyponatraemia

-  Hyperkalaemia

-  Serum ACTH

-  DDx primary from secondary

-  Elevated: primary

-  Decreased: secondary

-  Early morning plasma cortisol (within 1hr of waking)

-  <200nmol/L: adrenal insufficiency

-  >500mmol/L: excludes adrenal insufficiency

-  AXR

-  Adrenal calcium depositis: adrenal TB

-  +/- Mantoux/Quitiferon: TB

-  CT-Brain

-  Pituitary pathology

-  ACTH Stimulating Test (250mcg)

-  Most specific test for Dx

-  Blood &/or urine cortisol levels pre & post synthetic ACTH

-  Rapid ACTH test

-   Blood cortisol tested after 30-60min

-   Positive if poor or no response to challenge

-   If abnormal then perform long ACTH test

-   Normal >500nmol/L

-  Long ACTH test

-   ACTH over 48-72hr period

-   Blood &/or urine cortisol tested day prior & day 2 or 3 of ACTH

-   No production of cortisol: primary adrenal insufficiency

-   Normal production of cortisol: secondary adrenal insufficiency

-  +/- Insulin induced hypoglycaemia test

-  Aids DDx of primary vs secondary

-  Normally hypoglycaemia produces cortisol increase

-  +/- adrenal, thyroid & ovarian antibodies: if autoimmune cause

 

Mx

-  If suspecting Addisonian crisis Mx immediately prior to ACTH stimulating test

-  Referral to Endocrinologist

-  Addisonian Crisis

-  Mx of hyperkalaemia, hypoglycaemia & hypotension

-  IV Hydrocortisone

-  IV fluids: NS & Dextrose

-  Hormone replacement

-  Corticosteroid: Hydrocortisone (to replace cortisol + some mineralcorticoid action) daily or BD

-  +/- Mineralocorticoid: Fludrocortisone acetate (Florinef) daily

-  Increased oral salt intake

-  Surgical Mx

-  Due to stress of operation pts who need GA should be treated with IV Hydrocortisone & NS

-   Day prior until able take PO

-  ID bracelet/medical alert

 

 

 

References

 

RCPA Manual: Adrenocortical Insufficiency 25/10/2010

Addisons Society of Austrlaia: www.addisons.org.au/assoc/whatis.pdf

Australian Prescriber: Evaluation of Adrenocortical Function in Adults, www.australianprescriber.com/magazine/30/6/147/9