Adrenal insufficiency
D E FI N I T ION
Deficiency of adrenal cortical hormones (e.g. mineralocorticoids, glucocorticoids
and androgens).
AE T IOLOGY
Primary (Addison’s disease): Autoimmune (>70%).
Infections: Tuberculosis, meningococcal septicaemia (Waterhouse–Friderichsen syndrome),
CMV (HIV patients), histoplasmosis.
Infiltration: Metastasis (e.g. lung, breast, melanoma), lymphomas, amyloidosis.
Infarction: Secondary to thrombophilia
Inherited: Adrenoleukodystrophy1, ACTH receptor mutation.
Surgical: After bilateral adrenalectomy.
Secondary: Pituitary or hypothalamic disease.
Iatrogenic: Sudden cessation of long-term steroid therapy.
E P IDEMIOLOGY
Most common cause is iatrogenic. Primary causes are rare (annual
incidence of Addison’s is eight in 1 000 000).
H ISTORY
Chronic presentation: Non-specific vague symptoms such as dizziness, anorexia,
weight loss, diarrhoea, vomiting, abdominal pain, lethargy, weakness, depression.
Acute presentation (Addisonian crisis): Acute adrenal insufficiency with major haemodynamic
collapse often precipitated by stress (e.g. infection or surgery).
EXAMINA T I ON
Postural hypotension.
Increased pigmentation: Generalized but more noticeable on buccal mucosa, scars, skin
creases, nails, pressure points (resulting from melanocytes being stimulated by " ACTH
levels).
Loss of body hair in women (androgen deficiency).
Associated autoimmune conditions: e.g. vitiligo.
Addisonian crisis: Hypotensive shock, tachycardia, pale, cold, clammy, oliguria.
INVE S T I G A T IONS
Confirm the diagnosis: 9 a.m. serum cortisol < 100 nmol/L is diagnostic
of adrenal insufficiency. If 9 a.m. cortisol > 550 nmol/L: adrenal insufficiency is unlikely.
Patients with 9 a.m. cortisol of between 100 and 550 nmol/L should have a short ACTH
stimulation test (short Synacthen test): IM 250 mg tetracosactrin (synthetic ACTH) is given.
Serum cortisol <550 nmol/L at 30 min indicates adrenal failure.
Identify the level of defect ACTH: " in primary disease and # in secondary disease. Long
Synacthen test: One milligram tetracosactrin is given and cortisol is measured at 0, 30, 60,
90 and 120 min then at 4, 6, 8, 12 and 24 h. Patients with primary adrenal insufficiency
show no increase after 6.
Identify the cause: Autoantibodies (against 21-hydroxylase). Abdominal CT or MRI. Other
tests e.g. adrenal biopsy for microscopy, culture, PCR depending on the suspected
causes.
Check TFTs
Investigations in ‘Addisonian crisis’: FBC (neutrophilia), U&E (" urea, # Naþ, " Kþ), ESR or
CRP (" in acute infection), Ca2þ
(may be "), glucose (#), blood cultures, urinalysis, culture
and sensitivity (UTI may have triggered the crisis). CXR: May identify cause (e.g.
tuberculosis, carcinoma) or precipitant of crisis (e.g. infection).
MANAGEMENT
Addisonian crisis: Rapid IV fluid rehydration (0.9% saline, 1 L over
30–60 min, 2–4 L in 12–24 h).50ml of 50%dextrose to correct hypoglycaemia. IV 200mg
hydrocortisone bolus followedby 100mg6 hourly (until BP is stable). Treat the precipitating
cause (e.g. antibiotics for infection).Monitortemperature, pulse, respiratory rate, BP, satO2
and urine output.
1Adrenoleukodystrophy is an X-linked inherited disease characterized by adrenal atrophy and
demyelination
Adrenal insufficiency (continued)
Chronic: Replacement of glucocorticoids with hydrocortisone (three times/day) and mineralocorticoids
with fludrocortisone. Hydrocortisone dosage needs to be increased during
acute illness or stress. If associated with hypothyroidism, give hydrocortisone before
thyroxine (to avoid precipitating an Addisonian crisis).
Advice: Steroid warning card, Medic-alert bracelet, emergency hydrocortisone ampoule,
patient education.
COMPL I C A T IONS
Hyperkalaemia. Death during an Addisonian crisis.
P ROGNOS I S
Adrenal function rarely recovers, but normal life expectancy can be expected
if treated.
Type I (autosomal recessive disorder caused by mutations in the AIRE gene which encodes a
nuclear transcription factor.): Addison’s disease, chronic mucocutaneous candidiasis,
hypoparathyroidism.
Type II (Schmidt’s syndrome): Addison’s disease, diabetes mellitus Type 1, hypothyroidism,
hypogonadism.
†
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