b'Figure 5. Differential Diagnosis in Lymphatic Disorders: The St Georges Algorithmand fungal infections. Most of these skin conditionsin intestinal lymphangiectasia). Furthermore, the cause a breach in the epidermis and, therefore,presence of alpha 1-antitrypsin in a stool sample predispose patients to an increased risk of cellulitis/ confirms a protein-losing enteropathy related toerysipelas, which often worsens lymphedema.lymph leak into the gastrointestinal tract (e.g., in Most cases of primary lymphedema solely affect theintestinal lymphangiectasia).extremities, but some patients may present systemicImaging Techniquesinvolvement that gives rise to symptoms from theLymphoscintigraphy can be particularly useful inabdomen 50 . In these cases, patients must be referredthe diagnosis of primary lymphedema to help define for relevant clinical investigations. the phenotype. For example, what can seem to beSince primary lymphedema is a genetic disease, it isa unilateral lymphatic dysfunction clinically withimportant to screen patients for associated problems,unilateral leg swelling may prove to be bilateral on such as segmental hypertrophy, venous insufficiency,lymphoscintigraphy. Furthermore, different patternsintellectual disability, and dysmorphic features, duringof abnormal flow can be seen in different types of the diagnostic work-up. primary lymphedema e.g., lymphatic valvular incompetence in lymphedema distichiasis and Laboratory Tests functional hypoplasia (impaired uptake into the initial It is important to differentiate between isolatedlymphatics) in Milroy lymphedema. Venous duplex peripheral lymphedema and systemic forms. ultrasound scans can be helpful in diagnosingSystemic involvement of lymphatic impairment may venous valvular incompetence e.g., in lymphedema be supported with blood tests. We advise in restricteddistichiasis. The imaging of complex lymphatic and cases to perform a full blood count (e.g., lymphopeniavascular malformations and overgrowth syndromesin intestinal lymphangiectasia, monocytopenia inis described elsewhere in this document.Emberger syndrome due to GATA2 deficiency), GeneticsCD4/CD8 ratio (e.g., reduced in WILD syndrome), immunoglobulins (e.g., reduced in intestinalPrimary lymphatic anomalies are a highly hetero-lymphangiectasia) and albumin levels (e.g., reduced geneous group of conditions. The classification of | Standardized Approach for the Diagnosis and Management of Lymphedema (LE) and Lymphatic Diseases (LD)|15'