Imaging modalities have been suggested as useful adjuncts to the ISL staging to clarify the diagnosis. The lymphedema expert Dr. Ming-Huei Cheng developed a Chengs Lymphedema Grading tool to assess the severity of extremity lymphedema based on objective limb measurements and providing appropriate options for management. I. Grading
Grade 1: Spontaneously reversible on elevation. Mostly pitting edema. Grade 2: Non-spontaneously reversible on elevation. Mostly non-pitting edema. Grade 3: Gross increase in volume and circumference of Grade 2 lymphedema, with eight stages of severity given below based on clinical assessments. II. Staging
As described by the Fifth WHO Expert Committee on Filariasis, and endorsed by the American Society of Lymphology., the staging system helps to identify the severity of lymphedema. With the assistance of medical imaging apparatus, such as MRI or CT, staging can be established by the physician, and therapeutic or medical interventions may be applied:
Stage 0: The lymphatic vessels have sustained some damage that is not yet apparent. Transport capacity is sufficient for the amount of lymph being removed. Lymphedema is not present. Stage 1 : Swelling increases during the day and disappears overnight as the patient lies flat in bed. Tissue is still at the pitting stage: when pressed by the fingertips, the affected area indents and reverses with elevation. Usually, upon waking in the morning, the limb or affected area is normal or almost normal in size. Treatment is not necessarily required at this point. Stage 2: Swelling is not reversible overnight, and does not disappear without proper management.
Another form of hereditary lymphedema is Milroys disease caused by mutations in the VEGFR3 gene. Hereditary lymphedema is frequently syndromic and is associated with Turner syndrome, lymphedema–distichiasis syndrome, yellow nail syndrome, and Klippel–Trénaunay–Weber syndrome.One defined genetic cause for hereditary lymphedema is GATA2 deficiency. This deficiency is a grouping of several disorders caused by common defect, viz., familial or sporadic inactivating mutations in one of the two parental GATA2 genes. These autosomal dominant mutations cause a reduction, i.e. a haploinsufficiency, in the cellular levels of the genes product, GATA2. The GATA2 protein is a transcription factor critical for the embryonic development, maintenance, and functionality of blood-forming, lympathic-forming, and other tissue-forming stem cells. In consequence of these mutations, cellular levels of GATA2 are deficient and individuals develop over time hematological, immunological, lymphatic, and/or other disorders. GATA2 deficiency-induced defects in the lymphatic vessels and valves underlies the development of lymphedema which is primarily located in the lower extremities but may also occur in other places such as the face or testes (i.e. hydrocele). This form of the deficiency, when coupled with sensorineural hearing loss which may also be due to faulty development of the lymphatic system, is sometimes termed the Emberger syndrome.Primary lymphedema has a quoted incidence of approximately 1-3 births out of every 10,000 births, with a particular female preponderance to male ratio of 3.5:1 In North America, the incidence of primary lymphedema is approximately 1.15 births out of every 100,000 births Compared to secondary lymphedema, primary lymphedema is relatively rare.