Lymphedema
Basics
DESCRIPTION
- Lymphedema is a chronic progressive swelling in subcutaneous tissues, typically in an extremity or the genitals, due to protein-rich accumulation of interstitial fluid from disruption of the lymphatic system. It can be of primary or secondary origin.
- Primary lymphedema has three forms, all of which stem from a developmental abnormality of lymphatic flow. Not all primary lymphedemas are clinically evident at birth.
- Congenital lymphedema, due to anomalous development of lymph system
- Present at birth
- Lower to upper extremity ratio: 3:1
- 2/3 of cases are bilateral.
- May improve with age
- Lymphedema praecox (65–80% of primary lymphedema)
- Usually becomes evident at puberty but may appear between infancy and age 35 years
- 70% unilateral lower extremity (L > R)
- Lymphedema tarda: presents at age 35 years or older
- Congenital lymphedema, due to anomalous development of lymph system
- Secondary lymphedema is from an acquired abnormality of lymphatic flow, an injury to the lymphatic system.
- Common causes in children include the following:
- Postsurgical obstruction
- Burns
- Insect bites
- Infection
- Scar tissue from radiation
- Neoplasm
- Trauma
- Common causes in children include the following:
- Classification: There are several systems for grading the severity of lymphedema.
- The International Society of Lymphology (ISL) describes lymphedema using skin consistency and outcome.
- Stage 0: dormant condition where a patient might describe their extremity as heavy
- Stage I (mild): soft tissue that may pit, no dermal fibrosis; improves with elevation of extremity
- Stage II (moderate): evolving dermal fibrosis that does not pit; no improvement with limb elevation
- Stage III (severe): Tissue is swollen and thick; there may be peeling, discoloration, or trophic changes.
- The American Physical Therapy Association (APTA) describes lymphedema by measurement between the affected and unaffected extremity.
- Mild: girth difference <3 cm
- Moderate: girth difference of 3 to 5 cm
- Severe: girth difference of >5 cm
- The International Society of Lymphology (ISL) describes lymphedema using skin consistency and outcome.
EPIDEMIOLOGY
- Most lymphedemas in childhood are primary (or idiopathic) lymphedema (96%).
- Congenital lymphedema comprises 10–25% of primary lymphedema cases; lymphedema praecox, 65–80%; and lymphedema tarda, 10%.
- Affected males—most likely congenital and bilateral; affected females—most likely unilateral lymphedema praecox
- Secondary lymphedema is more common in adults and rare in children. In the United States, it is commonly from breast cancer; worldwide, due to filariasis
- Affects 1.15 of 100,000 in children <20 years
RISK-FACTORS
GENETICS
- Milroy disease
- Also known as hereditary lymphedema type IA
- A rare, autosomal dominant condition that affects lymphatic function
- Associated with mutations in the FLT4 gene that encodes vascular endothelial growth factor receptor 3
- Meige disease
- Hereditary lymphedema type II—familial lymphedema praecox
- Fabry disease
- A serious, X-linked inborn error of glycosphingolipid catabolism associated with progressive renal failure, cardiovascular disease, neuropathy, and angiokeratosis
- Lymphedema-distichiasis
- An autosomal dominant condition that presents with lymphedema and double rows of eyelashes
- The condition is associated with mutations in the FOXC2 gene.
- Other genetic conditions prone to lymphedema: Down, Turner, Noonan, yellow nail, Klippel-Trenaunay-Weber, and pes cavus
PATHOPHYSIOLOGY
- Abnormal accumulation of interstitial fluid due to the lymphatic load overwhelming the transport capacity of lymph vessels
- Lymph flow occurs under a low pressure system; unlike generalized edema, capillary filtration remains normal in patients with lymphedema.
- Initially, edema is pitting, whereas chronic edema is generally nonpitting as a result of fibrosis.
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Citation
Cabana, Michael D., editor. "Lymphedema." Select 5-Minute Pediatrics Topics, 7th ed., Wolters Kluwer Health, 2015. Medicine Central, im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14202/all/Lymphedema.
Lymphedema. In: Cabana MDM, ed. Select 5-Minute Pediatrics Topics. Wolters Kluwer Health; 2015. https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14202/all/Lymphedema. Accessed October 12, 2024.
Lymphedema. (2015). In Cabana, M. D. (Ed.), Select 5-Minute Pediatrics Topics (7th ed.). Wolters Kluwer Health. https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14202/all/Lymphedema
Lymphedema [Internet]. In: Cabana MDM, editors. Select 5-Minute Pediatrics Topics. Wolters Kluwer Health; 2015. [cited 2024 October 12]. Available from: https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14202/all/Lymphedema.
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