Metabolic presentations 3: Galactossaemia

Cite this article as:
Taciane Alegra. Metabolic presentations 3: Galactossaemia, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.28602

It’s 11am on Easter Monday in Dublin. Emily is a 6 day old baby girl, born at 37 weeks via normal vaginal delivery across the Irish sea in Wales while her mother was visiting some friends. When Emily was 3 days old her mother returned to Ireland to stay with her own mother for some early baby support. Since day two of life Emily has been vomiting after feeding. She is bottle fed and since yesterday she has only been accepting half of each bottle. Her mother initially thought she was tired from the long trip but has brought her to the ED this morning because she has been quiet, hasn’t been crying as usual with nappy changes and seemed too sleepy to take this morning’s bottle. 

Emily was born in good condition by spontaneous vaginal delivery at 37/40. Her birth weight was 2.9kg. She was jaundiced on the second day of life, but below phototherapy levels. 

Social history: Emily’s parents are both healthy and from the Irish Traveller Community. 

Emily’s weight today is weight 2.45kg (a 16% drop below her birth weight). She’s jaundiced, lethargic, her anterior fontanelle is sunken, and Emily looks dehydrated. You can palpate the liver 2 cm below the right costal margin. No spleen palpable. Otherwise no positive findings. She’s afebrile with normal observations.

This baby has some red flags that will make anyone concerned. She is vomiting, lethargic, jaundiced, dehydrated, has hepatomegaly and has lost 16% of her birth weight. Emily is definitely sick. The list of potential diagnosis is extensive, but sepsis should always be the top of your list.

As you’re taking bloods for an FBC, U&E, LFT, ammonia and blood culture you’re told that Emily is hypoglycaemic so you collect additional bloods for a hypoglycaemia screen.

First, let’s correct the glucose!

Follow your local guideline regarding the initial investigation and management of hypoglycaemia and give 10% Dextrose 2mL/kg IV as soon as possible. 

Bloods should be be collected prior to treatment, but do not delay treatment due to problems collecting samples.

As this could be a metabolic presentation, instigate a generic management approach:

  • Clinical stabilisation
  • Antibiotics
  • Stop feeds
  • Give maintenance fluids with electrolytes to maintain hydration

The hypoglycaemia screen

The hypoglycemia workup should preferably be collected while the patient is hypoglycaemic, before giving glucose.

The basic screen aims to identify the most common endocrine or metabolic conditions responsible for hypoglycemia. Briefly, it involves: glucose, ketones (Beta-hydroxybutyrate), insulin, cortisol, Growth Hormone (GH), ammonia, lactate, free fat acids, serum amino acids, acylcarnitines profile (Guthrie card) and urine for organic acids and ketones. 

Discussing them in depth is beyond the scope of this post, but if you want to learn more, you can refer to this post by PaediatricFOAMed. 

Find out if your institution has a “hypoglycaemia kit” ready to go, as hypoglycaemia in a neonate can be a stressful situation that requires quick action. 

Emily’s blood sugar normalises. She has a full septic screen and is started on intravenous broad spectrum antibiotics. But, what’s her diagnosis?

Emily is hypoglycaemic with raised ketones, a normal response we would expect as she’s using fat as an alternative source of energy. However, in addition to this, Emily has hepatomegaly and raised liver enzymes, which together with hypoglycaemia, point towards a diagnosis of galactosaemia.

The worldwide incidence of classic galactosaemia is around  1:45,000 live births. Some countries screen for galactosaemia in their newborn screening programmes (Ireland, UK, New Zealand and some parts of Australia). Because of its autosomal recessive inheritance, galactosaemia is more common in some ethnic groups. 

In Ireland, around 1 in every 16,200 babies born each year may have galactosemia, however in the Irish Traveller community, this incidence is approximately 1 in 450 births, compared to only 1 in 36,000 in the non-traveller Irish population. Because of the high incidence in babies born to parents from the travelling community, these babies are specifically screened earlier, on day 1 of life, in Irish maternity hospitals.

High risk babies’ diets should exclude galactose, so newborn babies of Irish travelling families are given soy-based formula rather than breast feeds or standard formula until their screening test result is known.

A bit about galactosemia

As per definition, “galactosemia” refers to disorders of galactose metabolism that include classic galactosemia, clinical variant galactosemia, and biochemical variant galactosemia (Gene Reviews). The most common is classic galactosemia, an autosomal recessive disorder, that occurs due to a defect in the enzyme galactose-1-phosphate uridyl transferase (GALT), important in the transformation of galactose into energy.

Galactosemia presents after the affected patient receives the sugar galactose, present in milk. Accumulation of galactose-1-phosphate results in damage to the brain, liver, and kidney. The diagnosis is made by measuring the (GALT) enzyme activity (that will be low); by detecting elevated concentration of galactose-1-phosphate in erythrocytes (the substrate); or by testing if there are pathogenic mutations (two copies) in the GALT gene. The presence of a reducing substance in a routine urine specimen may be the first diagnostic clue.

Liver failure is a predominant finding in galactosemia and, besides that, the affected neonate presents with vomiting, hypoglycaemia due to an inability to metabolise glucose, feeding difficulty, seizures, irritability, jaundice, hepatomegaly, splenomegaly, cataracts and Escherichia coli sepsis

Treatment of the newborn requires the exclusion of all lactose sources from the diet, instead using lactose-free formulas. This must be started immediately after the disorder is suspected clinically, whilst awaiting screening results in high risk groups, or following a positive newborn screening results.

Interestingly, if the galactose-free diet is started early enough, the symptoms will disappear, jaundice will resolve within days, liver and kidney functions return to normal, liver cirrhosis may be prevented and cataracts may clear. 

Later in life…

Even patients treated from the very first few days of life can develop complications as they grow up. Galactosaemia represents a spectrum with symptoms varying from mild growth retardation, delayed speech development, verbal dyspraxia, difficulties in spatial orientation and visual perception, and mild intellectual deficit. Neuropsychological problems can appear during adolescence.  

Unfortunately, ovarian dysfunction is an almost inevitable consequence that can’t be prevented even by a strict diet. It is often seen early in infancy or childhood with hypergonadotropism. 

References

Berry JT. Classic Galactosemia and Clinical Variant Galactosemia In: Adam , HH. Ardinger, RA. Pagon, S. E. Wallis, L. J. H. Bean, K. Stephens, & A. Amemiya (Eds.), GeneReviews® [online book].

 Berry, JT, Walter JH, Fridovich-Keil JL. Disorders of Galactose Metabolism. In: Saudubray J-M, Baumgartner MR, Walter JH. (editors) Inborn Metabolic Diseases. Diagnosis and treatment. 6th Edition. Springer 2016. 

HSE. A Practical Guide to Newborn Bloodspot Screening In Ireland. December 2018. https://www.hse.ie/eng/health/child/newbornscreening/newbornbloodspotscreening/information-for-professionals/a-practical-guide-to-newborn-bloodspot-screening-in-ireland.pdf 

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About Taciane Alegra

Taciane AlegraBrazilian General Paediatrician, living and working in Ireland. PhD in genetics and molecular biology. Enjoys a good chat, especially about different languages and cultures. In her free time she runs (not much) and enjoy the outdoors

Taciane Alegra
Author: Taciane Alegra Brazilian General Paediatrician, living and working in Ireland. PhD in genetics and molecular biology. Enjoys a good chat, especially about different languages and cultures. In her free time she runs (not much) and enjoy the outdoors

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