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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Medical Genetics · Very Long-Chain Acyl-CoA Dehydrogenase Deficiency

Emergency Preparedness: Recognizing and Treating a Crisis

At a Glance

For a child with VLCADD, illness, fasting, or physical stress can trigger a dangerous energy crisis. Start the personalized sick-day plan early, seek emergency care for red-flag symptoms or inability to keep fluids down, and expect urgent IV glucose treatment.

In the context of VLCADD, an emergency is any situation where your child’s body begins to break down its own fat stores for energy—a process called lipolysis [1][2]. This “catabolic state” is dangerous because it releases long-chain fats that the impaired enzyme cannot process, leading to the accumulation of harmful metabolites and a rapid loss of energy [3][2].

Emergency Triggers

A metabolic crisis is typically triggered by stressors that increase the body’s energy demands or prevent it from getting enough fuel:

  • Illness: Fever, vomiting, or diarrhea [4].
  • Fasting: Missing a meal or going past the prescribed fasting limit [2].
  • Physical Stress: Intense exercise, cold exposure, surgery, or anesthesia [5][6]. (Always contact your metabolic team before any planned medical procedures).

Recognizing the Red Flags

Because VLCADD can affect different organs, a crisis may present in distinct ways. You must seek emergency care immediately if you notice any of these signs.

1. Hypoglycemia (Low Blood Sugar)

VLCADD causes hypoketotic hypoglycemia, meaning the body has no backup “ketone” energy [7].

  • Red Flags: Extreme sleepiness (lethargy), difficulty waking the child, poor feeding, vomiting, or “floppiness” (hypotonia) [8][4].

2. Rhabdomyolysis (Muscle Breakdown)

This occurs when muscle cells are damaged and release their contents into the blood, threatening the kidneys [9].

  • Red Flags: Dark, tea-colored, or reddish-brown urine (myoglobinuria), severe muscle pain, extreme weakness, or refusing to walk [10][9].

3. Cardiac Decompensation (Heart Crisis)

In severe cases, the heart muscle can weaken or develop dangerous rhythms [11][12].

  • Red Flags: Rapid or labored breathing, unusual sweating, pale/bluish skin, or signs of shock (cold hands/feet, very low energy) [4][12].

Sick Day Rules: Managing at Home

At the first sign of illness (like a fever or mild cold), you must initiate your child’s written sick-day plan to prevent a crisis [13].

  1. Stop Catabolism: Follow your dietitian’s exact instructions for providing prescribed high-carbohydrate fluids (such as specific glucose polymers) at the frequency and volume specified for your child’s age and weight [1][13].
  2. When to Go to the ER: If your child exhibits any inability to tolerate the prescribed fluids, has repeated vomiting, feeds poorly, or shows any of the red flags listed above, the home phase has ended. Contact your metabolic team and proceed to the Emergency Room immediately [4]. If your child is seizing, blue, or struggling to breathe, call emergency services (911) and do not give them anything by mouth.

The Hospital Protocol

When you arrive at the ER, you are not there for a standard evaluation. You are there to stop a metabolic crisis.

  • Hand Over the Letter: You must hand the ER staff your child’s personalized emergency letter from the metabolic geneticist [14]. Ask the ER physician to page the metabolic specialist on call immediately.
  • IV Dextrose: The primary treatment is an infusion of intravenous glucose (often 10% dextrose, but the exact concentration, rate, and volume depend on your child’s specific protocol) to stop the body from burning fat [15][16].
  • Do Not Delay: Ask the ER team to draw critical labs (like CK levels, electrolytes, and liver/kidney markers) promptly, but do not delay starting the IV glucose while waiting for the results to come back [16][1].

Common questions in this guide

What can trigger a metabolic crisis in a child with VLCADD?
Illness with fever, vomiting, or diarrhea, missed meals or fasting, intense exercise, cold exposure, surgery, and anesthesia can trigger a crisis. Contact the metabolic team before planned surgery or anesthesia and follow the child’s prescribed fasting limits.
What symptoms mean my child needs emergency care for VLCADD?
Warning signs include unusual sleepiness or trouble waking, poor feeding, vomiting, floppiness, dark tea-colored urine, severe muscle pain, extreme weakness, refusal to walk, rapid or labored breathing, unusual sweating, or pale or blue skin. These can signal dangerously low blood sugar, muscle breakdown, or a heart problem. Seek emergency care immediately, and call emergency services if the child is seizing, blue, or struggling to breathe.
What should I do at home when my child with VLCADD becomes sick?
Start the child’s individualized sick-day plan at the first sign of illness, using the prescribed high-carbohydrate fluid in the exact amount and frequency recommended by the metabolic team. If the child cannot keep fluids down, vomits repeatedly, feeds poorly, or develops a red-flag symptom, contact the metabolic team and go to the emergency room.
What happens when a child with VLCADD arrives at the emergency room?
Give the ER staff the child’s personalized emergency letter and ask the physician to contact the metabolic specialist. The team may start intravenous glucose, often 10% dextrose, to stop the body from using fat for energy; the exact concentration, rate, and volume follow the child’s protocol. Critical tests such as muscle enzyme, electrolyte, liver, and kidney tests should be obtained promptly, but glucose treatment should not wait for the results.
Why is an emergency protocol letter important for VLCADD?
The letter gives emergency staff the child’s diagnosis and personalized instructions when rapid treatment is needed. Keep an updated copy easy to find, and ask the metabolic team which emergency department and after-hours contact are best for your child.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What specific high-carbohydrate fluid (and at what volume) should I use at home if my child gets sick?
  2. 2.At what exact point during a minor illness should we stop home management and go to the emergency room?
  3. 3.Can you provide a signed, updated 'Emergency Protocol' letter that I can hand to ER doctors?
  4. 4.Which local emergency department is best equipped to handle a VLCADD metabolic crisis?
  5. 5.Who do I call on the metabolic team if my child becomes ill after hours or on a weekend?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (16)
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    Very long-chain acyl-CoA dehydrogenase (VLCAD-) deficiency-studies on treatment effects and long-term outcomes in mouse models.

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    PMID: 28247148
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    Fasting induces prominent proteomic changes in liver in very long chain Acyl-CoA dehydrogenase deficient mice.

    Wang W, Palmfeldt J, Mohsen AW, et al.

    Biochemistry and biophysics reports 2016; (8()):333-339 doi:10.1016/j.bbrep.2016.08.014.

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    Evidence that Oxidative Disbalance and Mitochondrial Dysfunction are Involved in the Pathophysiology of Fatty Acid Oxidation Disorders.

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    [Genetic analysis of a child with very long chain acyl-CoA dehydrogenase deficiency].

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    A heterozygous missense mutation in adolescent-onset very long-chain acyl-CoA dehydrogenase deficiency with exercise-induced rhabdomyolysis.

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    Perioperative Management of a Patient With Very Long Chain Acyl-CoA Dehydrogenase Deficiency Undergoing Laparoscopic Sleeve Gastrectomy: First Report of Bariatric Surgery in VLCADD.

    Baig MA, Williams B

    Obesity surgery 2026; (36(1)):341-344 doi:10.1007/s11695-025-08347-w.

    PMID: 41348145
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    Rare Korean Cases of Very-long-chain Acyl-CoA Dehydrogenase Deficiency with a Novel Recurrent Mutation.

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    [Clinical features and ACADVL gene mutation spectrum analysis of 11 Chinese patients with very long chain acyl-CoA dehydrogenase deficiency].

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    Very-Long-Chain Acyl-Co-Enzyme A Dehydrogenase Deficiency Presenting as Rhabdomyolysis: First Case Report from Sri Lanka.

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    Fatty acid oxidation flux predicts the clinical severity of VLCAD deficiency.

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This page is for informational purposes only and does not constitute medical advice. A child’s metabolic team should provide the individualized sick-day plan and emergency protocol; seek emergency care for red-flag symptoms.

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