Type 2: Pediatric Secondary Lymphedema
Secondary lymphedema is a chronic swelling condition caused by damage to lymphatic vessels or nodes in an area of the body. While commonly thought of as an affliction of adults, secondary lymphedema can occur at any age.
I) How does pediatric secondary lymphedema occur?
The lymphatic system is comprised of lymphatic vessels and lymph nodes that normally act to clear excess fluid called ‘lymph’ from tissues of the body, and recycle it back into the blood stream. Along with the cardiovascular system (your arteries and veins), the lymphatic system is responsible for maintaining a healthy fluid balance, clearing cellular waste, and participating in immune surveillance.
If the lymphatic system fails to work properly, lymph fluid will accumulate in the affected area of the body, and swelling will occur. The stagnant lymph also results in local immune system suppression and increased susceptibility to infection.
If left unchecked, a patient will normally progress through the stages of lymphedema (see Table 1 below) culminating in permanent changes to the area including fibrosis (scar formation) and adipose deposition (fat accumulation). See our blog post: “Untreated Lymphatic Swelling Promotes Weight Gain by Altering Stem Cell Behaviour”.
Lymphatic injuries that can cause secondary lymphedema in children include:
- Malignant tumours which physically interfere with lymphatic function.
- Lymphatic damage caused by medical interventions including cancer treatment, or surgery such as to correct an undescended testicle (ref6).
- Severe traumatic injury that permanently damages lymphatic vessels or nodes.
- Infection causing severe inflammation.
- Other syndromes and disorders that can cause lymphatic damage:
- Amniotic band syndrome and hair-tourniquet syndrome in newborns.
- Congenital vascular malformations (of small arteries and veins).
Stages of Primary and Secondary Lymphedema in Children
The progression of lymphedema in children follows the same general pattern as for adults, regardless of the origin of the lymphedema (primary or secondary), or the location of the body region affected. The stages of lymphedema are described in Foldi’s scale (see Table 1). For head and neck lymphedema some modification to the stages has been proposed (see: “Patient Guide to Head and Neck Lymphedema Following Cancer Treatment“).
Table 1: Foldi’s scale describing the stages of lymphedema progression in children and adults.
|0||Small areas of scar tissue formation||No visible swelling||Lymphoscintigraphy|
|1||Small areas of scar tissue formation, high-protein swelling||Self-reversing swelling (elevation or sleep may reduce swelling), soft and ‘pitting’ (finger press leaves a temporary indent)||Medical history, visual inspection and palpation may be sufficient|
|2||Significant scar tissue formation, swelling, adipose (fat) accumulation||Irreversible swelling (unless treated), firm and non-pitting||Medical history, visual inspection and palpation may be sufficient|
|3||Extensive scar tissue formation, swelling, adipose (fat) accumulation||Extensive and irreversible swelling, firm and non-pitting, with some degree of physical debilitation||Medical history, visual inspection and palpation may be sufficient|
If left untreated and unmanaged, children with lymphedema will normally progress to stage 2 of the condition, and in some cases to stage 3.
Thankfully, age of lymphedema onset does not appear to influence how the disease progresses, nor its prognosis. Infants with lymphedema do not appear to have worse outcomes than children who develop it later in life (ref5,6).
Diagnosis of Primary & Secondary LE in Children
Physical examination and Medical History
If a practitioner is knowledgeable about lymphedema, the diagnosis of lymphedema in adults can most often be made based on medical history, visual inspection, and examining the skin and underlying tissue with their hands alone.
For children, this can be more of a challenge. For example, the reason for a swollen leg in a child can be difficult to determine as various potential causes must be first ruled out (ref7).
For this reason, medical history, visual inspection and hands-on palpation alone may not suffice for a diagnosis of lymphedema in children.
Lymphoscintigraphy is a very effective diagnostic tool for confirming the presence of lymphedema in both adults and children, as well as for understanding the location and degree of lymphatic obstruction. In the case of leg lymphedema, lymphoscintigraphy involves injecting a radioactive tracing agent into the feet of a patient and mapping the flow of the tracer over time as it travels through the legs’ lymphatics, using a radiation detecting camera or scanner.
Guidelines on when to use lymphoscintigraphy in children are unclear. Some groups do not consider lymphoscintigraphy to be appropriate or effective in young children (ref8, ref9). It has been proposed by another group to be suitable for children over 10, in order to ensure that the child can understand and effectively participate in the procedure (ref5).
Genetic testing can be useful for establishing the presence of a genetic syndrome linked to primary lymphedema in children. See above for a list of syndromes potentially implicated.
Magnetic resonance imaging (MRI) with or without contrast agents may be useful for ruling in lymphedema in infants and young children where lymphoscintigraphy is inappropriate, or to rule out other causes of swelling including tissue hypertrophy (ref3,9). It can be used to look for physical issues such as missing lymph nodes, or other vascular or lymphatic abnormalities.
Other Diagnostic Tools
- Physicians may order various additional tests, often in order to rule out alternative diagnoses. Recent studies indicate that physicians commonly order ultrasonography, as well as X-ray studies (computed tomography, and plain films) to better understand the source of swelling in children with lymphedema (ref6).
- Ultrasound can be used to determine if swelling is an accumulation of fluid, and of what type, or to look for vascular clots as an alternative cause. Doppler ultrasound can be used to help evaluate fluid flow in arteries, veins and lymphatic vessels.
- Prenatal ultrasound can be used to identify the presence of lymphedema in the third trimester of pregnancy.
- Common blood tests may also be helpful to rule out other potential causes of swelling, such as hypoproteinaemia.
Diagnosis and Treatment of Childhood Lymphedema is Often Delayed
The diagnosis of lymphedema in children is often delayed, and so too is proper care and management of the condition. This can result in considerable stress for the family and can create less favourable outcomes for the child.
Patients with primary lymphedema appear to wait longer for diagnosis and subsequent treatment than their peers with secondary lymphedema.
One study in Victoria Australia showed that people (of all ages) with primary lymphedema waited on average 9.4 years for a diagnosis, compared with 1.5 years for patients with secondary lymphedema (ref2). The delay in diagnosis for primary lymphedema patients is presumably in part due to the relative rarity of the condition, in part due to its transient nature at early stages, and in part due to having to rule out various alternative diagnoses.
Treatment of lymphedema in children may also be delayed due to a lack of knowledge about the condition and the available services to treat it. In the UK one study showed that after diagnosis, 16% of patients waited less than 6 months for a referral, and 55% waited less than 2 years, but 16% reported waiting 10-17 years after first showing symptoms (ref3).
To read part 1 of this article click here.
To read part 3 of this article click here.