Filariasis differential diagnosis
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Mohammed Abdelwahed M.D[2]
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Filariasis Microchapters |
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Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Filariasis differential diagnosis On the Web |
|
American Roentgen Ray Society Images of Filariasis differential diagnosis |
|
Risk calculators and risk factors for Filariasis differential diagnosis |
Overview
Lymphatic filariasis must be differentiated from other causes of lower limb edema, such as chronic venous insufficiency, acute deep venous thrombosis, lipedema, myxedema, cellulitis and causes of generalized edema. Hydrocele sholud be differentiated from other causes of testicular masses. Breast lymphedema must be differentiated from breast cancer.
Differentiating filariasis from other diseases
| Diseases | Symptoms | Signs | Investigations | |||||
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| History | Pain | Fever | Laterality | Scrotal swelling | Symptoms of primary disease | |||
| Lymphatic filariasis |
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+ | + | Bilateral | + |
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Preparing Blood Smears[edit | edit source]If you are using venous blood, blood smears should be prepared as soon as possible after collection (delay can result in changes in parasite morpholo Thick Smears[edit | edit source]Thick smears consist of a thick layer of dehemoglobinized (lysed) red blood cells (RBCs). The blood elements (including parasites, if any) are more concentrated (app. 30×) than in an equal area of a thin smear. Thus, thick smears allow a more efficient detection of parasites (increased sensitivity). However, they do not permit an optimal review of parasite morphology. For example, they are often not adequate for species identification of malaria parasites: if the thick smear is positive for malaria parasites, the thin smear should be used for species identification. Prepare at least 2 smears per patient! Place a small drop of blood in the center of the pre-cleaned, labeled slide. Using the corner of another slide or an applicator stick, spread the drop in a circular pattern until it is the size of a dime (1.5 cm2). A thick smear of proper density is one which, if placed (wet) over newsprint, allows you to barely read the words. Lay the slides flat and allow the smears to dry thoroughly (protect from dust and insects!). Insufficiently dried smears (and/or smears that are too thick) can detach from the slides during staining. The risk is increased in smears made with anticoagulated blood. At room temperature, drying can take several hours; 30 minutes is the minimum; in the latter case, handle the smear very delicately during staining. You can accelerate the drying by using a fan or hair dryer (use cool setting). Protect thick smears from hot environments to prevent heat-fixing the smear. Do not fix thick smears with methanol or heat. If there will be a delay in staining smears, dip the thick smear briefly in water to hemolyse the RBCs. Examination of skin snips will identify microfilariae of Onchocerca volvulus and Mansonella streptocerca. Skin snips can be obtained using a corneal-scleral punch, or more simply a scalpel and needle. The sample must be allowed to incubate for 30 minutes to 2 hours in saline or culture medium, and then examined for microfilariae that would have migrated from the tissue to the liquid phase of the specimen. Thin Smears[edit | edit source]Thin smears consist of blood spread in a layer such that the thickness decreases progressively toward the feathered edge. In the feathered edge, the cellsshould be in a monolayer, not touching one another. Prepare at least 2 smears per patient! Place a small drop of blood on the pre-cleaned, labeled slide, near its frosted end. Bring another slide at a 30-45° angle up to the drop, allowing the drop to spread along the contact line of the 2 slides. Quickly push the upper (spreader) slide toward the unfrosted end of the lower slide. Make sure that the smears have a good feathered edge. This is achieved by using the correct amount of blood and spreading technique. Allow the thin smears to dry. (They dry much faster than the thick smears, and are less subject to detachment because they will be fixed.) Fix the smears by dipping them in absolute methanol. | |
| Chronic venous insufficiency |
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+ | - | Bilateral | +
(If congenial , Venous insufficiency un testicular veins may form scrotal swelling) |
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Duplex ultrasound will demonstrate typical findings of venous valvular insufficiency | |
| Acute deep venous thrombosis |
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+ | - | Unilateral | - |
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| Lipedema | Patients may complain of pain,swelling and easy bruising.[1] | + | - | Bilateral | - |
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| Myxedema |
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+ | - | Bilateral | - | |||
| Cellulitis | Acute painful swelling and may be fever | + | + | Unilateral | - | Tenderness,hotness and may be flactuation if abscess formed | ||
| Other causes of generalized edema | History of chronic general condition(cardiac-liver-renal) | - | - | Bilateral | - | |||
References
- ↑ Herbst KL (2012). "Rare adipose disorders (RADs) masquerading as obesity". Acta Pharmacol Sin. 33 (2): 155–72. doi:10.1038/aps.2011.153. PMC 4010336. PMID 22301856.
- ↑ Child AH, Gordon KD, Sharpe P, Brice G, Ostergaard P, Jeffery S; et al. (2010). "Lipedema: an inherited condition". Am J Med Genet A. 152A (4): 970–6. doi:10.1002/ajmg.a.33313. PMID 20358611.