How is the diagnosis made?
Mitochondrial disease is difficult to recognize, because there are so many possible symptoms and they can range from mild to severe. There are some physical signs and symptoms (such as developmental delay, seizures, poor muscle tone, acid reflux, vision and hearing loss), which could lead someone to suspect mitochondrial disease.
You may notice one or more symptoms before you recognize that something may be wrong with your child. If you have a feeling that something isn’t right, have your child seen by a pediatrician. If there are physical signs and symptoms or your family history suggests a problem with metabolism, the pediatrician may refer your child to a specialist in neurology or metabolic diseases. At your first visit, the specialist will ask you questions about your child’s health and your family’s medical history. As well as gathering these facts, the specialist will give your child a complete physical and neurological examination.
A diagnosis of Mitochondrial disease may be confirmed with diagnostic tests, which include:
- Genetic testing – a blood test to check for mutations in the genetic material of the mitochondria.
- Muscle biopsy – taking a tiny sample of muscle to examine under a microscope.
- Magnetic Resonance Imaging and Spectroscopy (MRI and MRS)
- Blood tests for lactate and pyruvate – these enzymes in the blood can help diagnose and track many diseases.
- Urine tests for organic acids, which may indicate problems with metabolism present since birth (called inborn errors of metabolism).
- Forearm exercise testing – to check for the build-up of lactate in the forearm muscles, during exercise with a cuff that restricts blood flow.
- Exercise and muscle strength testing – to check strength and tolerance for physical activity.
Other tests may include:
a lumbar puncture (spinal tap) to test and evaluate fluid around the brain and spinal cord (cerebrospinal fluid or CSF)
echocardiogram (ECHO) to check if the heart muscle is affected
electroencephalogram (EEG) to check brain activity for seizures
pulmonary function tests (PFT or spirometry) to check how well the lungs are working