Metabolic diseases in children: Early diagnosis and treatment hold key

Metabolic diseases occur as a result of defects in normal homeostasis mechanisms of the body which includes metabolism of molecules such as amino acids, lipids and carbohydrates. As a result, toxic products can accumulate in various organs which leads to critical organ dysfunction. Disorders include failure of energy production or utilisation that may lead to involvement of muscles, heart, brain and kidneys.

While we focus on a large-scale basis on immunisation and infectious diseases in children, the awareness about metabolic diseases is often overlooked. The prevalence of metabolic diseases in newborn babies is around 1 in 1,000 as per Indian statistics. Around 27,000 infants annually is in need of care by metabolic specialists in India as per IAP statistics. This collectively constitutes a burden to the health sector.

In India, we diagnose metabolic diseases usually after the clinical symptoms develop while in most of the western countries, newborn screening for metabolic diseases is a policy.

Many of the metabolic diseases such as Urea cycle disorders, Maple Syrup urine disease, Tyrosinemia, Propionic Acidemia, Primary Hyperoxaluria etc if diagnosed in the newborn period, anticipatory measures can be taken and can avoid end-organ damage which leads to morbidity and mortality. Organ involvements such as the brain, kidney, and liver, if occurs in children it is irreversible and it’s important to take preventive measures. But certain metabolic diseases such as mitochondrial disorders have no definitive curative treatment.

What are the symptoms of metabolic diseases?

Clinical presentations of metabolic diseases include seizures, vomiting, lethargy, developmental delay, failure to thrive, jaundice, neurological deterioration, floppiness, poor sensorium along with fever or any acute crisis, rickets etc. Persistent hypoglycemia, cardiac involvement or liver failure can be a feature of metabolic disease as well. Possible malformations or dysmorphisms can also be present. A history of previous sibling death is an alarming situation to suspect metabolic disease for the child.

The diagnosis of metabolic diseases is mainly based on plasma and urine chromatography or genetic tests. Arterial blood gas analysis, blood sugar, blood lactate, ammonia, and urine ketone values along with a thorough clinical examination and history taking may aid in reaching a diagnosis.

Specialised treatment is available for many metabolic diseases such as Wilson Disease, Primary Hyperoxaluria and Tyrosinemia. Early diagnosis and early initiation of therapy in these conditions are crucial for better survival without organ involvement.

Proper diet control and supplementation with co-factors or co-enzymes constitute the mainstay of treatment in metabolic disorders. The liver is the largest organ which produces most of the enzymes needed for processing various metabolites. Liver transplantation is a curative therapy for a large variety of metabolic disorders such as urea cycle disorders. Clinical manifestations such as neurological involvement if persistent in spite of adequate nutrition therapy and supplementation an indication for liver transplantation in many conditions such as MSUD, Propionic acidemia etc.

Certain metabolic diseases present as liver cirrhosis and liver failure which anyways warrant liver transplantation. Many metabolic diseases such as glycogen storage disorders, Phenylketonuria, Tyrosinemia, Propionic Acidemia etc. can be managed with proper nutrition therapy and supplementation.

Proper and regular follow-up with metabolic specialists, metabolic dietitians and regular checkups for metabolite level is needed for assurance of a good quality of life. Adherence to special formula foods and to your metabolic clinic is mandatory to keep metabolic conditions under check. We should be proactive in doing universal newborn screening for metabolic diseases in India which leads to early diagnosis of such conditions and hence the neuro-developmental morbidity in children can be prevented.

The author is an Associate Consultant, Department of Pediatric Gastroenterology, Hepatology and Liver Transplant, KIMS HEALTH, Thiruvananthapuram.

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