4
Diagnosis
Primary Adrenal Insufficiency
21–OH Antibody
17–OH–Progesterone
CT Adrenals
• Infiltrative
Disease
• Adrenal
Hemorrhage
• Infections
• Malignant
Tumors
• Autoimmune
Al
• Consider
APS-1, APS-2
Adrenoleuko-
dystrophy
Idiopathic PAI
Genetic
Syndromes
(Rare CAH, AHC)
CAH
VLCFA (Males)
Infants, selected
children and adults
All >6 months age
The most common causes of PAI are autoimmune destruction of the adrenal
cortex in adults and CAH in children. These etiologies can be screened for using
21-hydroxylase antibodies and a baseline serum 17-hydroxyprogesterone level. Males
with negative 21-hydroxylase antibodies should be tested for adrenoleukodystrophy
with plasma VLCFAs. If these diagnoses are excluded, a CT scan of the adrenals
may reveal evidence of adrenal infiltrative processes or metastases. The individual's
clinical picture and family history may render some steps in the algorithm redundant
or suggest specific genetic syndromes. The latter includes subtypes of autoimmune
polyglandular syndromes or specific rare genetic disorders where adrenal failure is
part of a broader phenotype. A list of differential diagnoses is provided in Table 2.
Abbreviations: AHC, adrenal hypoplasia congenita; AI, adrenal insufficiency; VLCFA,
very long chain fatty acid.
a
17-OH progesterone >1000 ng/dL is diagnostic for 21-OH deficiency.
b
VLCFA should be measured in the initial evaluation of preadolescent boys. [Adapted from E. S.
Husebye, et al: Consensus statement on the diagnosis, treatment and follow-up of patients with
primary adrenal insufficiency. J Intern Med. 2014;275:104–115 (181), with permission.
© John Wiley & Sons, Inc.]
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(+)
(+)
(+)
a
(+)
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b
Figure 1. Diagnostic approach to the patient with PAI
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