Metabolic Crises: Recognizing and Managing Emergencies

A metabolic crisis is a life-threatening medical emergency for a child with Propionic Acidemia (PA) ^[1]. It occurs when the body enters a catabolic state—a condition where, because of illness, fasting, or lack of calories, the body begins breaking down its own muscle and protein for energy ^[2]. In PA, this breakdown releases toxic byproducts, like ammonia and organic acids, that the body cannot process, leading to a rapid and dangerous buildup in the blood and brain ^[3][4].

EMERGENCY WARNING:
If your child is unresponsive, having a seizure, experiencing severe breathing difficulty, or cannot keep down prescribed fluids/formula due to persistent vomiting, call emergency services (911) or go to the nearest emergency department immediately. Do NOT wait for a lab result. Identify your child as having Propionic Acidemia and present their individualized emergency letter to the triage nurse.

Common Triggers of a Crisis

Anything that causes the body to use up its energy reserves can trigger a crisis. The most frequent causes include:

• Infections: This is the most common trigger, including common colds, the flu, ear infections, or stomach bugs ^[5].
• Fasting or Poor Intake: Missing meals or a sudden decrease in how much your child is eating ^[6][7].
• Vomiting or Diarrhea: These lead to dehydration and prevent the body from absorbing necessary calories ^[5].
• Physical Stress: Surgery, high fever, or significant injury ^[8].

Red Flags: When to Seek Emergency Care

Early symptoms of a crisis can be subtle, but they can progress to a life-threatening state very quickly ^[1]. You should seek immediate emergency medical attention if your child shows any of the following “red flag” symptoms:

• Severe Lethargy: Unusually sleepy, very difficult to wake up, or “floppy” (hypotonia) ^[9][6].
• Altered Mental Status: Confusion, extreme irritability, or acting unlike themselves ^[6].
• Persistent Vomiting: Being unable to keep down fluids or their specialized medical formula ^[5][10].
• Rapid or Heavy Breathing: This may be a sign of metabolic acidosis, where the blood becomes too acidic ^[10][11].
• Seizures: Any new or unusual shaking or loss of consciousness ^[5].

Caregiver Illness Tracking Checklist:
When your child is sick, track the following and have the information ready for the metabolic team:

• [ ] Fluid and formula intake (exact amounts)
• [ ] Number of vomiting or diarrhea episodes
• [ ] Urine output (number of wet diapers or trips to the bathroom)
• [ ] Temperature
• [ ] Mental status (alert, sleepy, irritable)
• [ ] Time of the last dose of medication

What to Expect in the Hospital

When you arrive at the hospital, the medical team will follow specific, clinician-directed protocols to stop the toxic buildup ^[2]. These steps are highly individualized based on your child’s age, weight, lab results, and the metabolic team’s protocol. The attending doctors will consult immediately with your metabolic team. Potential treatments include:

1. High-Calorie IV Fluids: The team may provide intravenous (IV) glucose (sugar) and electrolytes. This provides the “fuel” the body needs to stop breaking down its own protein ^[2].
2. Protein Adjustment: Natural protein intake is often temporarily withheld to prevent further toxin production, but it is usually reintroduced as soon as the catabolism is controlled to prevent essential amino acid deficiency ^[12].
3. Ammonia Management: If hyperammonemia (high ammonia) is present, doctors might use medications like carglumic acid, though this is not used in every PA crisis. It helps unlock a backup pathway in the body to process and remove ammonia ^[2][13].
4. Carnitine Support: High doses of IV levocarnitine (carnitine) may be given to help the body “package” and flush out harmful acids through the urine ^[12].
5. Frequent Lab Work: Doctors will frequently check levels of ammonia, blood pH (blood gas), electrolytes, and glucose ^[14].

Advanced Life-Saving Measures

In severe cases where ammonia levels are dangerously high or not responding to medications and fluids, the medical team may consider hemodialysis or continuous renal replacement therapy (CRRT) ^[15][16]. This decision is based on clinical signs, ammonia trends, and neurological findings. These machines filter the blood and manually remove toxins to protect the brain ^[17][18].

The Importance of Your Emergency Plan

Because many emergency room doctors may have never treated a patient with PA, you must always carry your child’s individualized emergency sick-day plan ^[19]. This letter provides the exact instructions for IV fluid rates, medication doses, and metabolic team contact numbers. Hand this letter to the triage nurse immediately upon arrival. This guide is educational and does not replace your child’s written sick-day plan.