unilateral leg swellingCase: A 55 year old female visiting the United States from southern Mexico presents with 6 months of chronic unilateral lower extremity swelling and 2 days of erythema. What is the most common cause of this chronic disease? Click on image for a larger view.

Poll Results

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Filariasis

Explanation

This patient has chronic lymphedema with superimposed cellulitis. Lymphedema can be primary or secondary. The much more common secondary lymphedema occurs from damage to the lymphatic system by disorders as 1 :

  • Chronic venous insufficiency
  • Filariasis
  • Malignancy
  • Obesity
  • Radiation therapy
  • Surgery
  • Trauma

Initially, lymphedema is soft and pitting. With time, subcutaneous tissue fibrosis occurs, leading to indurated skin that is difficult to compress. The pathognomonic finding, the Kaposi–Stemmer sign, is an inability to pinch a fold of skin at the base of the dorsal second toe between the examiner’s thumb and forefinger. 2 Other findings of lymphedema include:

  • Cobblestone appearance
  • Dependent rubor (resembling cellulitis)
  • Dimpling of the skin (peau d’orange)
  • Hyperpigmentation
  • Nodules (representing dilated lymphatics)
  • Ulceration and crusting
  • Verrucous skin surface

Eventually, the leg may become massive and disfigured, a condition labeled as elephantiasis. The most common cause worldwide is filariasis. Wuchereria bancrofti, Brugia malayi, and Brugia timori are endemic to tropical areas of the world and are transmitted by a mosquito vector carrying the infected larvae. Patients actively infected with the parasite are treated with diethylcarbamazine (DEC) or doxycycline. 3

In the United States, edema most commonly occurs after axillary, pelvic or inguinal lymph node dissection for neoplastic disease. Most patients are treated conservatively with compression therapy (including compressive garments), physical therapy, or pneumatic pumps. Surgery is rare. 4

Clinical Bedside Pearls: Dr. Jeff Riddell

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1.
Murdaca G, Cagnati P, Gulli R, et al. Current views on diagnostic approach and treatment of lymphedema. Am J Med. 2012;125(2):134-140. [PubMed]
2.
Hirschmann J, Raugi G. Lower limb cellulitis and its mimics: part II. Conditions that simulate lower limb cellulitis. J Am Acad Dermatol. 2012;67(2):177.e1-9;  quiz 185-6. [PubMed]
3.
Parasites – Lymphatic Filariasis. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/lymphaticfilariasis/. Published June 14, 2013. Accessed September 26, 2014.
4.
Szuba A, Rockson S. Lymphedema: classification, diagnosis and therapy. Vasc Med. 1998;3(2):145-156. [PubMed]
Jeff Riddell, MD

Jeff Riddell, MD

ALiEM Assistant Editor
Diagnose on Sight series;
Medical Education Research Fellow
University of Washington / Harborview Medical Center
Jeff Riddell, MD

@jeff__riddell

emergency physician. teacher. education scholar. thinking about #MedEd thru the lens of digital innovation. LAC+USC, TTCoOp, ALiEM, Essentials of EM
Jeff Riddell, MD

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