Pediatric Endocrinology

Recognizing Symptoms and Emergency Red Flags

At a Glance

In CMO II deficiency, vomiting, diarrhea, or illness can quickly cause salt loss and dangerous dehydration. Call emergency services for severe sleepiness, shock signs, breathing changes, seizures, or fainting, and follow the child’s written sick-day plan.

Living with CMO II deficiency means becoming an expert in your child’s “normal” ^[1]. For most children receiving treatment, life is routine and involves regular medication and salt administration ^[2]. However, because your child’s body cannot hold onto salt naturally, certain situations—especially vomiting or diarrhea—can quickly lead to a salt-wasting crisis ^[3]^[4].

Routine Symptoms vs. Warning Signs

In the early days of diagnosis, you may notice symptoms that are concerning but often stabilize once treatment is balanced ^[4]. These include:

Slow Weight Gain: Also called failure to thrive, this is a common early sign of CMO II ^[1].
Mild Feeding Issues: Being a “picky” or “fussy” eater or having occasional spit-ups ^[5]^[6].
Increased Sleepiness: Your baby might seem a bit more tired than other infants ^[5].

These symptoms require monitoring and follow-up with your pediatrician or endocrinologist to safely adjust medication or salt doses ^[7]^[8].

What is a Salt-Wasting Crisis?

Physiologically, a salt-wasting crisis happens when the kidneys dump too much sodium into the urine ^[9]. Because water follows salt, the body’s blood volume drops rapidly (dehydration), and levels of potassium can climb to dangerous heights (hyperkalemia) ^[10]^[11]. This can lead to hypovolemic shock, where the heart cannot pump enough blood to the rest of the body ^[3]^[12]. A salt-wasting crisis is a severe medical emergency.

Tiered Emergency Action Plan

Always follow the individualized written sick-day plan provided by your endocrinologist. As a general guide, triage symptoms into the following categories:

🚨 Tier 1: Call 911 / EMS Immediately

If you notice any of these severe signs of shock or crisis, call emergency services immediately. Do not wait for lab results.

Altered Mental Status: Your child is very difficult to wake up, appears “limp” like a ragdoll, or is completely unresponsive ^[13]^[14].
Signs of Shock: Pale, cool, or mottled skin; very fast or very weak pulse; or bluish tint to the lips and nails ^[15]^[13].
Breathing Changes: Very fast, shallow breathing or struggling to catch their breath ^[16]^[13].
Seizures or Fainting: Any sudden loss of consciousness or rhythmic jerking movements ^[17]^[14].

🏥 Tier 2: Urgent Emergency Room Evaluation

Seek prompt emergency medical care if your child:

Has Repeated Vomiting: If your child vomits multiple times or cannot retain their prescribed fludrocortisone or salt supplements ^[4]^[18].
Shows Severe Dehydration: A drastic reduction in wet diapers, a sunken soft spot (fontanelle) on the head, or crying without tears ^[3]^[19].

☎️ Tier 3: Same-Day Endocrine Contact

Contact your pediatric endocrinology team for same-day advice and medication adjustments if your child:

Has a fever (especially urgent if the infant is younger than 3 months) ^[18]^[20].
Has diarrhea or a new illness but is still holding down fluids ^[18].
Has a noticeable decrease in wet diapers, but is still producing some ^[19].
Experiences a single, large spit-up of their medication (ask your team whether to re-dose) ^[5].

Important Safety Warning: Never try to manage severe dehydration at home with plain water or unmeasured table salt. Plain water can dangerously dilute the blood’s remaining sodium, worsening the crisis. Only use the specific prescribed fluid and sodium products exactly as directed by your medical team. Bringing a one-page “Emergency Letter” detailing your child’s condition and exact medication doses to the ER is critical to ensuring rapid, correct care ^[20]^[21].

Common questions in this guide

What are the early symptoms of CMO II deficiency in a child?

Early symptoms can include slow weight gain, feeding difficulties, occasional spit-ups, and more sleepiness than usual. These changes should be monitored and discussed with the child’s pediatrician or endocrinology team so treatment and salt doses can be reviewed.

What happens during a salt-wasting crisis?

The kidneys lose too much sodium, and water follows the salt, causing the body’s blood volume to fall quickly. Potassium can rise to dangerous levels, leading to severe dehydration, shock, and a medical emergency.

When should I call 911 for a child with CMO II deficiency?

Call emergency services immediately if the child is very difficult to wake, limp, unresponsive, pale or cool, has a very fast or weak pulse, develops blue lips or nails, struggles to breathe, has a seizure, or faints. Do not wait for laboratory results when these signs are present.

When does vomiting require emergency care in CMO II deficiency?

Repeated vomiting or inability to keep down prescribed fludrocortisone or salt supplements requires prompt emergency evaluation. A major reduction in wet diapers, a sunken soft spot, or crying without tears can indicate severe dehydration and also requires urgent care.

What should I do if my child has a fever, diarrhea, or another illness?

Follow the child’s written sick-day plan and contact the pediatric endocrinology team for same-day advice, especially for a fever in an infant younger than 3 months. If the child cannot keep down fluids or prescribed medicines, seek emergency care rather than waiting.

Can I give plain water or unmeasured table salt during a salt-wasting crisis?

No. Plain water can dilute the sodium left in the blood, and unmeasured salt can cause dangerous dosing errors. Use only the specific fluid and sodium products prescribed by the medical team and follow emergency instructions.

Get notified when new evidence is published on corticosterone methyloxidase type 2 deficiency.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.

References (21)

1
Catch-up Growth and Discontinuation of Fludrocortisone Treatment in Aldosterone Synthase Deficiency.
Gurpinar Tosun B, Kendir Demirkol Y, Seven Menevse T, et al.
The Journal of clinical endocrinology and metabolism 2022; (107(1)):e106-e117 doi:10.1210/clinem/dgab619.
PMID: 34415991
2
Analysis of novel heterozygous mutations in the CYP11B2 gene causing congenital aldosterone synthase deficiency and literature review.
Miao H, Yu Z, Lu L, et al.
Steroids 2019; (150()):108448 doi:10.1016/j.steroids.2019.108448.
PMID: 31302112
3
Congenital aldosterone deficiency and its resistance.
Tajima T, Amano N, Ishii T, et al.
Endocrine journal 2026; (73(6)):751-763 doi:10.1507/endocrj.EJ25-0630.
PMID: 41905953
4
Clinical and Genetic Characteristics of Patients with Corticosterone Methyloxidase Deficiency Type 2: Novel Mutations in CYP11B2
Turan H, Dağdeviren Çakır A, Özer Y, et al.
Journal of clinical research in pediatric endocrinology 2021; (13(2)):232-238 doi:10.4274/jcrpe.galenos.2020.2019.0216.
PMID: 32539318
5
[Clinical and genetic analysis of an infant with aldosterone synthase deficiency].
Yang H, Chen Q, Zhang L, et al.
Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 2021; (38(9)):865-868 doi:10.3760/cma.j.cn511374-20200302-00121.
PMID: 34487532
6
Congenital hyperreninemic hypoaldosteronism due to aldosterone synthase deficiency type I in a Portuguese patient - Case report and review of literature.
Lages AS, Vale B, Oliveira P, et al.
Archives of endocrinology and metabolism 2019; (63(1)):84-88 doi:10.20945/2359-3997000000107.
PMID: 30864636
7
Neonatal salt wasting syndrome: Aldosterone synthase deficiency caused by a new splicing variant in CYP11B2.
Gerard R, Sauvestre C, Barat P, et al.
Archives de pediatrie : organe officiel de la Societe francaise de pediatrie 2024; (31(2)):157-160 doi:10.1016/j.arcped.2023.10.007.
PMID: 38262861
8
Cracking the code of aldosterone synthase deficiency: bridging genetics and biochemistry: a case report.
Kamarajan LP, Mahto M, Kumar S, Kumar P
Laboratory medicine 2025; (56(4)):419-422 doi:10.1093/labmed/lmae102.
PMID: 39700478
9
Functional properties of the γ-ENaC-A635V mutation in a patient with severe hyponatremia.
Antoniadi M, Bohnet M, Kellenberger S, et al.
Hormones (Athens, Greece) 2025; (24(2)):581-587 doi:10.1007/s42000-025-00637-3.
PMID: 40153144
10
Aldosterone deficiency with a hormone profile mimicking pseudohypoaldosteronism.
Martín-Rivada Á, Argente J, Martos-Moreno GÁ
Journal of pediatric endocrinology & metabolism : JPEM 2020; (33(11)):1501-1505.
PMID: 32809961
11
Corticosterone Methyl Oxidase Type 1 (CMO1) Deficiency Due to CYP11B2 Mutation: Two Case Reports.
Ur Rehman S, Aftab S, Naseem A, et al.
Cureus 2023; (15(5)):e39181 doi:10.7759/cureus.39181.
PMID: 37332400
12
Congenital primary adrenal insufficiency and selective aldosterone defects presenting as salt-wasting in infancy: a single center 10-year experience.
Bizzarri C, Olivini N, Pedicelli S, et al.
Italian journal of pediatrics 2016; (42(1)):73 doi:10.1186/s13052-016-0282-3.
PMID: 27485500
13
Vomiting and Cardiac Arrest in a 10-Year-Old Girl.
Zorko DJ, Samaan MC, Gupta R
Pediatric emergency care 2021; (37(12)):e1747-e1749 doi:10.1097/PEC.0000000000001957.
PMID: 32011558
14
Treatment and Prevention of Adrenal Crisis and Family Education
Çamtosun E, Sangün Ö
Journal of clinical research in pediatric endocrinology 2025; (17(Suppl 1)):80-92 doi:10.4274/jcrpe.galenos.2024.2024-6-12-S.
PMID: 39713905
15
Deciphering aldosterone deficiency and pseudodeficiency in infancy by targeted GC-MS urinary steroid metabotyping.
Li H, Pons-Kühnemann J, Hartmann MF, Wudy SA
The Journal of steroid biochemistry and molecular biology 2027; (265()):107103 doi:10.1016/j.jsbmb.2026.107103.
PMID: 42603653
16
A novel compound heterozygous mutation in CYP11B2 (p.A153P and p.Q337*) associated with primary hypoaldosteronism.
Yang J, Li L, Sun Y, et al.
Frontiers in medicine 2026; (13()):1740124 doi:10.3389/fmed.2026.1740124.
PMID: 41889508
17
[Adrenal crisis in a child].
Holmberg NH, Haagensen AL
Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke 2023; (143(2)) doi:10.4045/tidsskr.22.0354.
PMID: 36718904
18
SFE/SFEDP adrenal insufficiency French consensus: Introduction and handbook.
Reznik Y, Barat P, Bertherat J, et al.
Annales d'endocrinologie 2018; (79(1)):1-22 doi:10.1016/j.ando.2017.12.001.
PMID: 29338844
19
Adrenal insufficiency management in the pediatric emergency setting and risk factors for adrenal crisis development.
Abrigo E, Munarin J, Bondone C, et al.
Italian journal of pediatrics 2023; (49(1)):63 doi:10.1186/s13052-023-01475-y.
PMID: 37280667
20
Emergency management of adrenal insufficiency in children: advocating for treatment options in outpatient and field settings.
Miller BS, Spencer SP, Geffner ME, et al.
Journal of investigative medicine : the official publication of the American Federation for Clinical Research 2020; (68(1)):16-25 doi:10.1136/jim-2019-000999.
PMID: 30819831
21
Diagnosis and Treatment of Primary Adrenal Insufficiency: An Endocrine Society Clinical Practice Guideline.
Bornstein SR, Allolio B, Arlt W, et al.
The Journal of clinical endocrinology and metabolism 2016; (101(2)):364-89 doi:10.1210/jc.2015-1710.
PMID: 26760044

This page is for informational purposes only and does not replace medical advice or your child’s individualized sick-day plan. Follow your pediatric endocrinologist’s instructions and call emergency services for severe symptoms.