All about breastfeeding, an APILAM blog: Breastfeeding in infants suffering from chylothorax

This article discusses the possibility of using fat free breastmilk in the treatment of a disease fortunately rare: chylothorax.

We used an appropriate

language

to reduce the complexity to non-professionals without sacrificing outreach to spread among professionals (residents and specialist of Pediatrics, Neonatology and Pediatric surgery and nursing staff of neonatal and pediatric units). The discussion in the subject may be not as deep as to wake the interests in experts versed in the matter.

Definition

Chylothorax is extravasation of chylous lymph of the lymphatic system into the pleural space.

Anatomical-physiological Remembrance

The lymphatic system is composed of numerous ducts or very fine lymphatic capillaries which converge into two thicker ducts, right or upper duct which collects lymph from the right parts of the head and trunk and right arm; and thoracic duct lymph collecting from the rest of the body. Both ducts just converge into the subclavian veins. The thoracic duct runs parallel to the superior vena cava and the aorta. In addition to carrying lymph, after meals, transports long-chain fatty acids, greatly increasing its volume to more than 5 times, depending on the amount and type of fat ingested.

Lymph is derived from a liquid blood extravasation into the interstitial tissues of the body. Most of the blood supply to the tissues through arteries and out through the capillaries to nourish and provide oxygen to the body cells back to the heart through the venous system, but some is trapped in the interstitial tissue and is collected by the lymphatic capillaries back to the heart. It is a parallel return system of support to the venous system.

Fats (most are triglycerides) that we eat are hydrolyzed (digested) by means of enzymes (lipases) and transformed into smaller pieces called fatty acids, so they can be absorbed by the intestinal cells. Lipase which makes this digestion is secreted by the pancreas. Newborns do not have a lot of pancreatic lipase, but you can find it in the saliva of the mouth and, in addition, in the mother's breastmilk, which helps digest fats.

Once digested and absorbed, if the fatty acids are not very large molecule (less than 14 carbon atoms: short and medium chain) they pass the portal vein to the liver with no further problems. If they are larger (long chain), they pass up the lymphatic system and the thoracic duct into the venous system. When the lymph is mixed with fat meals in the thoracic duct, is called chyle.
Thus the lymphatic system, in addition to draining lymph extravasated of the body, leads fats into the venous system of the intestine. The lymphatic system also has an immune function, of defense against infections and other attacks, which is not addressed here.

Etiology of chylothorax (causes)

The absence, malformation or ruptured thoracic duct causes the lymph not to drain into the venous system, making it to drain into the chest out and accumulating in the pleural space (space between the lungs and the lining of the pleura), promoting pleural effusion of chylous lymph (fat) called chylothorax that causes shortness of breath and loss of fat, protein and defenses in the body.

When the lymph carries more than 110 mg/dL of fat (triglycerides) in composition, we talk about chyle, which is a milky sap.

In the first months of life chylothorax can occur:

After surgery of congenital malformations (heart disease, esophageal atresia, diaphragmatic hernia, etc..) In which the the thoracic duct is inadvertently transected (about 5% of cardiac surgery).
In case of congenital malformations associated with other, chromosomal (Down's syndrome, for example) or not and in isolation (idiopathic).
More uncommon, for the pipe (a catheter) in the subclavian or jugular veins, can pierce the thoracic duct.

Treatment

To relieve respiratory distress involving pleural effusion, pleural punctures are used and repeated aspirations or continuous drainage of chylothorax, with the drawback that the patient loses large amounts of fat, protein, minerals, lymphocytes and immunoglobulins (defenses) contained in that liquid. It is necessary to adequately replenish these losses.

Conservative treatments are associated (non-surgical) that essentially try to minimize or eliminate lymphatic flow through the thoracic duct and so, by keeping it in relative rest, get the spontaneous closure of the defect. They can be special diets or drug treatments.

Over 70% of patients improve with special formulas free or with low amount of long chain fatty acids and, instead, enriched with medium chain triglycerides (MCT). You can not give the usual milk formulas because tthey contain long-chain triglycerides.

Many services choose to stop breastfeeding because breast milk has about 75% fat in the form of long-chain triglycerides, whose absorption and transport overload the drainage system of the thoracic duct.

But it has proven totally successful a conservative treatment of chylothorax which consists on feeding whith defatted breast milk after centrifugation and removal of the fat layer.

It is a simple procedure available to many hospitals that can be achieved with a refrigerated centrifuge at 2 ° C at 3000 rpm for 15 minutes. It takes 1 hour to process 1 liter of milk. With fewer calories, it can be enriched with MCT and glucose. We must also add soluble vitamins.

Other conservative treatments, not without side effects are:

Total parenteral nutrition (artificial feeding through a vein) accompanied by total or partial fasting.
Octreotide (a drug substance similar to the hormone somatostatin) which, by reducing intestinal absorption is also another option.

The average time of introduction of normal diet are 9 days (range 3-59) so you should know if you want to keep breastfeeding through regular extraction and frozen.

The best effectiveness of the various conservative treatments is still not clear.

Given the intrathoracic situation and fineness and delicacy of the thoracic duct (in adults is less than 4 mm in diameter), reconstructive surgery is a difficult choice and reserved for when conservative treatments have failed.

Use fat-modified breastmilk during the critical period, until the duct is closed and chylous effusion ceases and then continue with full breastmilk, get benefit from the huge anti-infective properties of breast milk as the immunoglobulin A (IgA). In addition, lactoferrin and lysozyme are unaffected by the removal of fats, in fact negligible in children usually under continuous risk of infection.

In addition, mothers feel included and valued in the treatment of his son and motivated to maintain their lactation.

Dr. José María Paricio Talayero

Acknowledgements:
To Belen Abarca Sánchis, Neonatal ICU nurse at the Hospital Gregorio Marañón (Madrid), instructor of the LLL, mother and IBCLC, who asked me and suggested the preparation of this post.
To Breastfeeding Photo Contest Marina Alta from grup Nodrissa for the images of breastfeeding.
To all the people that with their suggestions, comments and discrepancies have helped to improve the quality and to better reflect the reality of a complex situation.
Drawings of the lymphatic system: Gerhard Wolf-Heidegger. Systematischen Atlas Anatomie des Menschen. Ed S.Karger. Basel, 1961

References

Biewer ES, Zürn C, Arnold R, Glöckler M, Schulte-Mönting J, Schlensak C, Dittrich S.

Chylothorax after surgery on congenital heart disease in newborns and infants -risk factors and efficacy of MCT-diet. Texto PDF

J Cardiothorac Surg. 2010 Dec 13;5:127.

Medoff-Cooper B, Naim M, Torowicz D, Mott A.

Feeding, growth, and nutrition in children with congenitally malformed hearts.

Cardiol Young. 2010 Dec;20 Suppl 3:149-53.

Lumbreras Fernández J, Sánchez Díaz JI.

Quilotórax: experiencia en una unidad de cuidados intensivos pediátricos.
Chylothorax: experience in a paediatric intensive care unit.

An Pediatr (Barc). 2009 Mar;70(3):223-9.

Prada Arias M, Rodríguez Barca P, Carbajosa Herrero MT, de Celis Villasana L, Viñals González F.

Quilotórax tras reparación de atresia de esófago: tratamiento conservador con octreotida.

Chylothorax following repair of oesophageal atresia: conservative treatment with octreotide.