Congenital Adrenal Hyperplasia (CAH)

Guidance for primary care clinicians receiving a positive newborn screen result

Other Names

CAH

ICD-10 Coding

E25.0, Congenital adrenal hyperplasia

Disorder Category

Endocrine disorder

Screening

Abnormal Finding

Elevated 17-Hydroxyprogesterone (17-OHP)

Tested By

17-OHP is measured by Fluoroimmunoassay - abnormalities on the first assay trigger a second-tier test using the liquid chromatography, followed by tandem mass spectrometry (LC-MS/MS). Second-tier tests significantly increase the specificity and sensitivity of CAH screening. Because 17-OHP levels are affected by birth weight and gestational age and can be elevated in sick infants, the normal range must be adjusted in those circumstances.

Description

Congenital adrenal hyperplasia comprises a group of autosomal recessive disorders caused by deficient adrenal corticosteroid enzyme, leading to inadequate synthesis of cortisol in the adrenal gland. Newborn screening programs screen for the most common form, 21-hydroxylase deficiency, which accounts for ~95% of congenital adrenal hyperplasia. 21-hydroxylase deficiency leads to impaired production of cortisol and aldosterone and resultant excess production of adrenocorticotropic hormone (ACTH). This leads to chronic stimulation of the adrenal gland without normal production of cortisol but with overproduction of androgens. 21-hydroxylase deficiency causes 2 types of congenital adrenal hyperplasia:
  • The "classic" form has severe enzyme deficiency and prenatal onset and has two subtypes: simple virilizing and salt wasting. Both types can be life-threatening in infancy due to cortisol deficiency.
  • The “non-classic” form is milder and presents later with variable degrees of postnatal androgen excess.

Clinical Characteristics

A cardinal feature of classic CAH in newborn females is virilization (enlarged clitoris, posterior labial fusion, and rugation of the labia and urogenital sinus formation). Female infants are frequently diagnosed at birth with ambiguous genitalia.
With treatment of congenital adrenal hyperplasia with gluco- and mineralocorticoid replacement, near-normal growth and life expectancy should result. Surgical management of virilization may be indicated in females.
Without treatment, life-threatening salt-wasting crises may occur, even before the newborn screening results are reported; hypoglycemia may also occur with stress.
If not recognized early and treated, initial symptoms may include:
  • Virilization in female infants (ambiguous genitalia)
  • Vomiting
  • Lethargy
  • Poor feeding
  • Pallor
  • Shock
  • Lab findings including:
    • Metabolic acidosis
    • Hyponatremia
    • Hyperkalemia
    • Hypoglycemia

Incidence

The incidence of congenital adrenal hyperplasia ranges from 1:10,000 to 1:20,000 births, but it is more prevalent in small, genetically isolated groups. [Speiser: 2018]

Inheritance

Autosomal recessive

Primary Care Management

Next Steps After a Positive Screen

  • Contact the family immediately and evaluate the infant for poor feeding, lethargy, and vomiting; perform serum electrolytes and 17-OHP.
  • Provide emergency treatment/referral for symptoms of vomiting or evidence of electrolyte imbalance.
    • If the infant is ill, regardless of electrolyte results, admit to the hospital for further evaluation and fluid management.
    • If the infant appears well and the electrolytes are abnormal, admit to the hospital for further observation and management.
    • If the infant appears well and the electrolytes are normal, observe and await the 17-OHP results.

Confirming the Diagnosis

  • To confirm the diagnosis of congenital adrenal hyperplasia, work with Newborn Screening Services (see ID providers [22])
  • A positive screen is an emergency; the family should be contacted immediately and additional testing performed: serum 17-OHP; serum electrolytes (high potassium, low sodium, low bicarbonate); blood glucose (low).

If the Diagnosis is Confirmed

  • Contact Pediatric Endocrinology (see ID providers [2])as soon as possible for assistance with evaluation and ongoing collaborative management, including possible gender assignment issues.
  • Further evaluation may include urologic surgery consultation.
  • See Endocrine Society Clinical Practice Guideline [Speiser: 2018].
  • Educate the family regarding signs and symptoms of salt wasting and adrenal crisis.
  • Initiate and support the maintenance of glucocorticoid and mineralocorticoid replacement therapy as indicated.
  • Electrolytes, hormone levels, and renin should be monitored as necessary.

Resources

Information & Support

Related Portal Content
After a Diagnosis or Problem is Identified
Families can face a big change when their baby tests positive for a newborn condition. Find information about A New Diagnosis - You Are Not Alone; Caring for Children with Special Health Care Needs; Assistance in Choosing Providers; Partnering with Healthcare Providers; Top Ten Things to Do After a Diagnosis.

For Professionals

Congenital Adrenal Hyperplasia (GeneReviews)
Detailed information addressing clinical characteristics, diagnosis/testing, management, genetic counseling, and molecular pathogenesis; from the University of Washington and the National Library of Medicine.

Congenital Adrenal Hyperplasia (OMIM)
Information about clinical features, diagnosis, management, and molecular and population genetics; Online Mendelian Inheritance in Man, authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine

For Parents and Patients

Facts about CAH (NIHCC) (PDF Document 313 KB)
Patient education material from the National Institutes of Health Clinical Center

Facts about CAH (NIHCC) (PDF Document 313 KB)
Patient education material from the National Institutes of Health Clinical Center

Congenital Adrenal Hyperplasia: A Guide for Families (PES) (PDF Document 138 KB)
Fact sheet for families from the Pediatric Endocrine Society

21-hydroxylase deficiency (MedlinePlus)
Information for families that includes description, frequency, causes, inheritance, other names, and additional resources; from the National Library of Medicine.

Congenital Adrenal Hyperplasia Research, Education & Support (CARES) Foundation
Information for parents and providers with treatment suggestions, links to research and support groups, news about conferences, and parent-to-parent tips.

Tools

ACT Sheet for Congenital Adrenal Hyperplasia (ACMG) (PDF Document 348 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

Confirmatory Algorithms for Congenital Adrenal Hyperplasia (ACMG) (PDF Document 213 KB)
An algorithm of the basic steps involved in determining the final diagnosis of an infant with a positive newborn screen; American College of Medical Genetics.

Services for Patients & Families in Idaho (ID)

Genetics clinic services throughout the US can be found through the Genetics Clinic Services Search Engine (ACMG).

For services not listed above, browse our Services categories or search our database.

* number of provider listings may vary by how states categorize services, whether providers are listed by organization or individual, how services are organized in the state, and other factors; Nationwide (NW) providers are generally limited to web-based services, provider locator services, and organizations that serve children from across the nation.

Studies

Congenital Adrenal Hyperplasia (ClinicalTrials.gov)
Studies looking at better understanding, diagnosing, and treating this condition; from the National Library of Medicine.

I-CAH Registry
The International Congenital Adrenal Hyperplasia Registry, funded by the United Kingdom Medical Research Council, was developed to support research and improvement in clinical care of patients with congenital adrenal hyperplasia.

Authors & Reviewers

Initial publication: March 2007; last update/revision: May 2019
Current Authors and Reviewers:
Author: Dania M. Al-Hamad, MBBS
Senior Author: Mary A. Murray, MD
Authoring history
2007: first version: Nicola Longo, MD, Ph.D.R
AAuthor; CAContributing Author; SASenior Author; RReviewer

Page Bibliography

Speiser PW, Arlt W, Auchus RJ, Baskin LS, Conway GS, Merke DP, Meyer-Bahlburg HFL, Miller WL, Murad MH, Oberfield SE, White PC.
Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline.
J Clin Endocrinol Metab. 2018;103(11):4043-4088. PubMed abstract / Full Text
Comprehensive guideline addressing aspects of CAH from newborn screening through long-term management.