Symptoms, Triggers & Emergency Management

For a child with LCHAD deficiency, a common cold or a skipped meal is not just a minor inconvenience—it can be the start of a metabolic crisis. Because your child’s body cannot break down long-chain fats for energy, they are “metabolically fragile.” Understanding how to spot a crisis early and knowing exactly when to head to the emergency room are the most important tools you have as a parent ^[1][2].

Why the Crisis Happens: Hypoketotic Hypoglycemia

In a healthy body, when sugar (glucose) runs low, the liver burns fat to create ketones, which act as a backup fuel. In LCHAD deficiency, the body tries to switch to fat but gets stuck.

• Hypoketotic: This means the body is not producing enough ketones ^[3].
• Hypoglycemia: This is low blood sugar ^[4].

Because there is no backup fuel (ketones) and the primary fuel (sugar) is gone, the body’s organs begin to “starve” for energy. Simultaneously, the partially broken-down fats begin to build up and become toxic to the liver and heart ^[5][6].

Recognizing the Triggers

A metabolic crisis is usually “triggered” by something that forces the body to look for energy. The most common triggers include:

• Fasting: Going too long without eating, which varies by age (e.g., 4 to 8 hours) ^[7][8].
• Illness: Fever, vomiting, or diarrhea. Fever increases the body’s energy needs, while vomiting prevents the intake of necessary carbohydrates ^[7][2].
• Sustained Exercise: Intense or long-duration physical activity can deplete sugar stores quickly ^[7].
• Vaccinations: Routine childhood vaccines can cause fever. You should proactively set up a ‘sick-day’ plan with your doctor before immunization appointments ^[2].

Warning Signs: When to Act

At the very first sign of a mild illness (like a sniffle), you should begin your at-home ‘sick-day’ plan, which often involves special high-carbohydrate drinks and more frequent feeding to prevent a crisis before it starts ^[7]. Early signs of a true crisis can be subtle, but you should be on high alert if you notice:

• Lethargy: Excessive sleepiness or difficulty waking your child up ^[9].
• Irritability: Unusual or inconsolable crying ^[9].
• Poor Feeding: Refusing their formula or special diet ^[7].
• Vomiting: Any illness that prevents your child from keeping down their “sick-day” fluids is an immediate emergency ^[7].

A Note on Rhabdomyolysis

During a crisis, the body may try to break down muscle for energy. This is called rhabdomyolysis ^[10]. You might notice your child has muscle pain or dark-colored urine (often described as looking like tea or cola). Doctors monitor this by checking creatine kinase (CK) levels, a marker of muscle damage, in the blood ^[4][11].

The Emergency Protocol: “Do Not Wait”

If your child shows signs of a crisis or cannot keep fluids down, you must go to the emergency room immediately. Do not wait to see if they feel better.

1. Hand over the Emergency Letter: If you do not already have one, ask your metabolic specialist to draft and sign this letter immediately upon diagnosis. This document tells the ER doctors exactly what to do, even if they have never treated LCHAD before ^[12].
2. Immediate IV Fluids: The goal in the ER is to stop the body from burning fat (lipolysis). This is done by giving high concentrations of intravenous (IV) fluids containing dextrose and essential electrolytes (like sodium), such as D10 or D12.5. The electrolytes are crucial because giving pure dextrose without them can cause a dangerous drop in blood sodium ^[7][10].
3. Reverse the Crisis: The IV sugar provides the energy the body needs, which signals the body to stop trying to burn fat, thereby stopping the production of toxic intermediates ^[7][8].

By acting quickly, you can “turn off” the metabolic crisis before it causes lasting damage to the heart, liver, or brain ^[1]. Your quick action is the bridge that keeps your child safe until their metabolism stabilizes.