Overview

Krabbe Disease - also known as globoid cell leukodystrophy - is a genetic autosomal recessive disease caused by the deficiency of the enzyme galactocerebrosidase.¹ The lack of this enzyme causes a build-up of the toxin psychosine in the central and peripheral nervous system, which leads to many neurological symptoms.¹

However, the neurological symptoms are not the only ones that affect patients with Krabbe disease: individuals often experience feeding impairment,² especially in regards to swallowing. Children affected by Krabbe may begin with gastroesophageal reflux and vomiting, and in adulthood, difficulty swallowing is retained due to impaired reflexes and poor muscle tone.² The consequences of not addressing these feeding issues can be incredibly harmful: malnutrition, weight loss, and failure to thrive and grow are just some of the many that can affect patients with Krabbe. 

In this article, we will explain some of the strategies implemented by care professionals to combat these feeding difficulties.

Common feeding difficulties in krabbe

Feeding difficulties in Krabbe can affect patients of any age, but do not affect every patient with Krabbe disease - however, they are very common. In a study by Bascou N, DeRenzo A, Poe MD, Escolar ML,³ 72% of children with Krabbe were affected by feeding difficulties.³ They constitute a major challenge for healthcare professionals seeking to improve the quality of life of patients around the world.

The most common feeding difficulties showcased in Krabbe disease are:

1. Poor swallowing
2. Reduced ability to suck and chew
3. Gastroesophageal reflux
4. Constipation
5. Choking³

The first two can be attributed to the neuromuscular issues caused by Krabbe disease. The build-up of psyching and the absence of galactocerebrosidase cause the myelin sheath surrounding neurons to break down, which means the brain cannot transmit signals properly to the muscles in the mouth and throat to aid swallowing and chewing.⁴

Gastroesophageal issues occur in Krabbe due to the loss of myelin sheath around the autonomic nerves responsible for digestion, which can lead to impaired digestion and reflux.⁵ The muscles responsible for gastric emptying are also impaired by the loss of myelin, leading to constipation in patients affected by Krabbe disease. The inability to control and coordinate the muscles that allow us to swallow also causes any liquids to be aspirated into the lungs, which can lead to choking, aspiration pneumonia or gastroesophageal reflux.

These issues can be very scary for both patients and family members to deal with, especially choking, which can be a life-threatening event. Fortunately, there are many techniques in place to help people affected by Krabbe deal with feeding, and we will talk about them in the next section.

Common feeding strategies

Feeding techniques are an essential part of the treatment plan for patients with Krabbe disease. They can lead to a great improvement in quality of life when tailored to the needs of the individual patient. Due to the variety of feeding issues exhibited by people affected by the disease, there are many feeding strategies which can be implemented:

1. Positioning² 
2. Adjusting feeding time²
3. Texture modification diet⁶
4. Oral motor therapy¹
5. Nasogastric tube⁷
6. Gastrostomy⁷

We will now discuss each one of these feeding strategies. Positioning refers to the practice of correcting one’s posture to ensure the patient will not choke or struggle to swallow; for example, positioning the body upright and offering neck support to keep the patient’s head straight while they eat.¹ This is a non-invasive strategy and can be successful in patients whose ability to swallow and chew is not severely impaired. 

Another non-invasive strategy is adjusting the patient’s feeding time. Instead of three large meals a day, this practice aims to offer smaller, frequent meals in order not to overwhelm the patient’s system and to reduce the risks of reflux and choking.¹

But it is not all about how to eat: what to eat is just as important. Patients affected by Krabbe may struggle with the texture of food rather than the type of food: something like a chewy steak could be a major choke hazard for them. A texture-modified diet is often implemented for people who struggle to swallow and chew, and is very useful in Krabbe disease as it greatly reduces the risk of choking.⁶ In a texture-modified diet, all types of food are blended and made into a puree or liquid, which removes the aspect of chewing and lowers the risk of choking.⁶ However, some patients do not like this method as it may not look as appetising as solid food, so sometimes they may need some psychological support to come to terms with this new diet.

Oral motor therapy is a therapy where the patient is asked to complete muscular exercises - usually involving the mouth - to improve their ability to swallow and chew.¹ An example of the exercises involved are chewing plastic or rubber objects, blowing whistles and using oral motor tools.⁸ However, exercises can be tailored to individual needs and abilities. Often, to aid patients further, assistive devices may be used, such as special bottles and caps.⁸

All the aforementioned therapies aim to work on the patient’s abilities, however, they may not be effective for everyone. Some people’s symptoms are too severe to be able to wait for the benefits these therapies bring, and they may need more invasive methods to help them feed and prevent malnutrition. 

If we want to be able to feed individuals who need urgent care, then a nasogastric tube^7,9 may be used. A nasogastric (NG) tube is a short-term measure used by healthcare professionals: the tube is placed without surgery through the nose and is passed until it reaches the stomach.⁹ It is not very invasive as it does not require surgery, and it is a very safe way of feeding patients who are not able to do so on their own. However, some patients find them uncomfortable, especially when they are being inserted. They also carry a higher risk of aspiration, which could be dangerous in patients with Krabbe as they have a risk of aspiration already, caused by their condition.⁹

If we want to be able to feed individuals in the long term, then a gastrostomy tube^7,9 may be used. A gastrostomy involves a surgical procedure where an artificial opening is created through the abdomen and a tube is inserted, accessing the stomach and delivering food directly.⁹ This is often a more stable way of feeding patients, however, it carries surgical risks - such as infection, complications, etc - and may seem scarier to a patient considering their options. 

These are the strategies applied by healthcare professionals when aiming to feed individuals affected by Krabbe, however, there are other issues that need to be considered, such as the gastrointestinal and respiratory problems that patients with Krabbe face. The next section will address these issues.

Managing gastric and respiratory issues when feeding

Feeding difficulties do not limit themselves to poor swallowing and chewing: the risks of reflux and aspiration into the lungs are always present and need to be addressed to improve the patient’s quality of life. The main techniques involved in managing gastric and respiratory issues when helping patients with Krabbe are:

1. Treatment for gastroesophageal reflux
2. Diet for constipation
3. Adding thickeners to liquids
4. Monitoring after meals

Gastroesophageal reflux - also known as GERD - is a common problem for many people, and so there are a range of medications to combat it. There are over-the-counter options, such as antacids,¹⁰ which neutralise stomach acid, however many of these are meant to be used in the short term and should not be used in the long term.¹⁰ Prescription medications for GERD include histamine-receptors antagonists, proton pump inhibitors and baclofen.¹⁰ Histamine-receptor antagonists stop the histamines in the body and reduce stomach acid, however, they are not suitable for the long term.¹⁰ Proton pump blockers are strong acid blockers and they also work on healing.¹⁰ Baclofen, on the other hand, is a muscle relaxant that reduces muscle spasms and aims to reduce the frequency of reflux events.¹⁰

A better diet can also be effective for both reflux and constipation: a diet rich in fibres¹¹ can increase stool frequency¹¹ in constipated patients and can also help reduce acid reflux.¹² 

To prevent aspiration, liquids can be thickened to make it more difficult for them to be aspirated into the lungs. Thicker liquids¹³ are slower in the body and give it more time to close the airway and block off the pathway to the lungs. However, it is important to note that thicker liquids are more likely to leave behind a residue and can therefore contribute to aspiration post-swallowing. There is more evidence¹³ that suggests that thicker liquids are a good treatment option, so they are still very much used for patients with Krabbe.

Lastly, monitoring patients with Krabbe after meals² is another strategy to ensure that they have no reflux or aspiration events. Careful monitoring for any warning signs can ensure early intervention and prevent severe damage. This relies completely on healthcare professionals - whether in a hospital setting or at home - or even on family members, which can be stressful and more time-consuming, but ultimately it does guarantee some protection for the patient.

FAQs

How is krabbe disease diagnosed?

Krabbe disease is diagnosed through a range of tests. Genetic testing can identify the gene defect,¹ sometimes before the baby’s birth. Blood tests can measure the level of galactocerebrosidase in the blood: low levels of the enzyme would indicate Krabbe disease.⁷ CT scans and MRI scans may indicate lesions and damage to areas of the brain.¹ Currently, in many countries, there are mandatory tests at birth to find out whether babies do or do not have Krabbe disease.¹⁴ A combination of these tests, as well as a thorough medical history and physical exam, will bring a diagnosis of Krabbe.

What are the treatment options for krabbe disease?

Krabbe disease is considered a fatal disease that worsens over time, and there is no cure. However, a range of treatment options exist to try to slow the progression of the disease. Most commonly, patients are offered supportive care, such as physical therapy, feeding tubes and palliative care.¹⁵ 

There are two main treatments that are used before the appearance of symptoms to slow down the progression of the disease: Hematopoietic stem cell transplant (HSCT) and cord blood stem cell transfusion.¹⁵ HSCT, which is the most common of the two, involves the transplantation of stem cells from a donor to a patient.¹⁶ In cord blood stem cell transfusion, stem cells from a donor’s umbilical cord are transplanted to the patient.¹⁶

How is krabbe disease inherited?

Krabbe disease is an autosomal recessive disease, which means children of parents who are carriers (have one recessive gene for the disease but the dominant one suppresses it) have a 25% chance of inheriting the disease, a 50% chance of being a carrier and a 25% chance of being unaffected at all.¹⁷  This makes the disease very rare.

Summary

Krabbe disease is a rare genetic condition which has a range of symptoms, mainly neurological, and feeding impairment is a big part of it. It is essential that patients are looked after and able to eat, therefore strategies to combat their difficulties are extremely important. These feeding difficulties, such as constipation, gastroesophageal reflux and swallowing issues, can have severe consequences - i.e. malnutrition - if left untreated. Strategies to manage feeding include positioning, adjusting feeding times, texture-modified diets and oral motor therapy. In more severe cases, nasogastric and gastrostomy tubes may be used. The respiratory and gastrointestinal issues that patients with Krabbe face, such as aspiration, must also be managed: this can be done through dietary adjustments, medication and monitoring. Unfortunately, there is no discovered cure for Krabbe, but early intervention and a personalised treatment plan can greatly improve the quality of life of patients.