Elephantiasis
Diag n o s t i c Image C o mpendium
COMPILED BY
JULIA GUNDLING
0187666
B I O L 2 1 8 H U M A N A N AT O M Y
FA L L 2 0 1 0
Elephantiasis
Diag n o s t i c Image C o mpendium
•
The following collection of images present a pathological condition called lymphatic filariasis,
more commonly known as elephantiasis.
•
The intention for this presentation is to outline an example of what can happen when the
lymphatic system is unable to function normally, to provide information about this specific
disease (lymphatic filariasis), and to highlight current methods of treatment and prevention.
•
First, we will review the lymphatic system, outlining its structures and functions under normal
conditions. This is followed by an introduction to what happens within this system during a
pathological stress.
•
Then proceeds a discussion of the disease itself, including causes, symptoms, diagnoses, etc. Each
of these topics is illustrated using diagnostic images and diagrams.
•
Finally, this report concludes with a review of current treatments and prevention techniques
employed to deal with this tragic condition.
Overview of the Lymphatic System
Thelymphatic systemis a network of tissues and organsarrangedthroughoutthe humanbody.It consists of
lymph vessels, lymph nodesand lymph fluid.
Lymphvessels carrylymph fluid throughoutthe body,analogous to howarteriesand veins transport blood.
Scatteredthroughoutthesevessels are lymph nodes,which aresmall oval lymphoidorganswhere blood
vessels and nervesattach. Nodes filter and purify lymph, removingand digestingdebris, antigens and
pathogensas lymphflows past. Lymphnodesare distributedthroughoutthe bodyin a general pattern.
Lymphfluid is an interstitial fluid that carries white blood cells, which defendthe bodyagainst germs. It is
composedprimarily of lymphocytes(accounting for 99%of the cells in lymph). The rest are phagocytic
macrophages, eosinophils and neutrophils. Lymph is normallyclear and coagulable, passing through
intercellular spaceswithin tissues,enteringcirculationthroughducts, filtering throughporesin capillary
walls, and travelling throughthe lymph nodesbeforeeventually mixing back into the blood. Lymph picks up
bacteria and foreignsubstances,delivering themto the lymph nodeswhere they arethen destroyed. Lymph
not only transports cells, but also bathesthe cells with water and nutrients. The spleen carries a number of
lymphnodes that fight infection. The thymus and bone marrowproducelymph cells.
IMAGE 1:
Lymph
nodes are
distributed
throughout
the body in
a general
pattern
Thelymphatic system is the body’s primary mechanism of defense.It clears away infectionand keepsbodyfluids
in balance. It deposits excess fluids and proteinsback into the bloodstream.
IMAGE 2:
Lymph
vessels
carry fluid
throughout
the body
analogous
to how
arteries and
veins
transport
blood.
Here, a
lymph
vessel
(yellow) is
pictured
alongside
blood
vessels.
If the lymphatic systemdoes not functionproperly, fluids
build up within tissues.This results in lymphedema,an
accumulationof lymphfluid that causesswelling.
Lymphedemaresults frominfection, obstruction of the
lymphaticsystem,cancer, scar tissue(fromradiation
therapyor surgical removal of lymph nodes) and from
inherited conditions (in which the structural componentsof
the lymphatic systemare either abnormal or absent).
Elephantiasis is a severe expressionof lymphedema.
IMAGE 3: Anatomy of a Lymph Node
What is Elephantiasis?
IMAGE 4
Lymphatic filariasis (elephantiasis) is a chronic disease characterized by
abnormal enlargement of any part of the body due to obstruction of the
lymphatic channels in that area.
The most common cause of this disease is infestation by parasitic,
microscopic thread-like worms of several different genera, including
Wuchereria bancrofti, Brugia malayi and B. timori. The adult worms
live only in the human lymph system, where they obstruct the normal
flow and function of lymph fluid causing inflammation, fibrosis and
edema. Conditions can be greatly worsened by secondary bacterial and
fungal infections that the impaired lymphatic system is no longer able
to combat.
Female mosquitoes are the vector for this disease, carrying the parasite
from one individual to another. When an infected mosquito bites a
human, parasitic worm larvae are injected into the bloodstream where
they reproduce and spread into the lymph.
People with the disease suffer from severe lymphedema, characterized
by the thickening of the skin and underlying tissues especially in the
limbs. In men, swelling often occurs in the scrotum, a condition called
hyrocele, which in some cases can be quite severe.
Elephantiasis may also occur in the absence of parasitic infection,
referred to as “nonfilarial elephantiasis” or “podoconiosis.”
IMAGE 4 shows the life cycle of
Brugia malayi in the mosquito vector
and then in the human host through
both the infective and diagnostic
stages. IMAGE 5 shows how the
parasite is passed from vector to host.
IMAGE 6 is a photomicrograph of an
adult Brugia malayi worm at the
diagnostic (human host) stage.
IMAGE 7 shows a cluster of Brugia
malayi worms as they multiply within
the lymphatic system.
IMAGE 6
IMAGE 5
IMAGE 7
IMAGE
Pathogenesis
IMAGE 8: Histological presentation of lymphatic
fibrosis (thickening of the dermis and
subcutaneous layers that results from excessive
production of fibrous connective tissues)
IMAGE 9: Fibrosis showing affected lymph vessels.
Lymphatic filariasis is a complex interaction between several factors . . . the worm, symbiotic
Wolbachia bacteria within the worm, the host’s immune response and any number of other
opportunistic infections that arise to take advantage of the impaired immune defenses of an
obstructed lymphatic system. As the parasites accumulate in lymph vessels, they can restrict the
circulation of lymph fluid and cause fluid to pool in surrounding tissues.
The accumulation of protein-rich lymph fluid in the affected body region is thought to induce
fibroblast proliferation and impair local immune response. Unchecked proliferation of
fibroblasts results in excessive production of fibrous connective tissue, resulting in a thickening
of the dermis and subcutaneous tissues. Diminished immune response creates a greater
possibility of lymphangitis, a recurrent inflammation which leads to further fibrosis in the
dermis and the lymphatic system. As the affected area becomes increasingly thickened and
fibrosed, lymphedema worsens and the condition progresses.
Lymphedema of the tissues in an affected area appears as papules, lesions, abnormal enlargements
and woody fibrosis.
IMAGE 10: Lymphangitis; inflammation of
lymph tissues
IMAGES
12 and 13>>
show
abnormal
enlargement
of limbs and
tissues as a
result of
lymphedema
IMAGE 11: Early signs of lymphangitis; external signs
of lymph inflammation
Clinical Presentation
Symptoms of elephantiasis often do not present until years after infection.
Symptoms of acute and chronic infection include:
•
•
•
•
•
•
•
Fever
Pain in and near the testicles
Enlarged lymph nodes, particularly in the groin region
Massively swollen legs, torso, genitalia and breasts
White urinary discharge
Swollen liver
Swollen spleen
Elephantiasis is a progressive disease. Without intervention deformity and
disability are ongoing and debilitating.
The following IMAGES 14-19 all show the various forms and symptoms of elephantiasis.
Prevalence and Demographics
According to the Center for Disease Control and Prevention, lymphatic filariasis is globally considered to be a “Neglected Tropical
Disease,” a grouping of infectious diseases known to cause tremendous suffering. These diseases are characterized by their debilitating,
disfiguring and sometimes deadly effects. In fact, lymphatic filariasis is a leading cause of permanent disability worldwide.
Elephantiasis is common in tropical regions where the mosquito vector thrives and where preventive resources are scarce, such as in
parts of Africa, India and on tropical islands. Nonparasitic forms of elephantiasis also show wide dispersion and are thought to caused by
persistent contact with irritant soils (particularly red alkali clays associated with volcanic activity). High prevalence has been documented
in Uganda, Ethiopia, Rwanda, Kenya, Burundi, Sudan, Tanzania, Egypt and Cameroon.
Individuals with elephantiasis are frequently disabled to the point of being unable to work. This affects families and communities. Women
and men disfigured by the disease are frequently shunned. Endemic occurrence is common, as more than one individual within the same
community may be affected by the mosquito vector.
IMAGE 20: This map
shows the global
distribution of
lymphatic filariasis.
Bright red coloration
refers to those
countries where the
disease is endemic.
Pale green identifies
those countries where
lymphatic filariasis is
not endemic, and pink
highlights those
regions where it is
uncertain whether or
not prevalence e of the
disease is endemic.
Treatment
Without intervention, lymphatic filariasis causes progressive deformity and usually results in
death due to related complications. Recovery is possible, but any elephantiasis that
develops in the course of the disease is irreversible.
The disease can be treated with medication, but this is not always straightforward as the
medications are most effective when administered soon after infection and elephantiasis is
difficult to detect early. Also, some of the medications have toxic side effects. Drug
treatments include:
IMAGE 21: A diagnostic CT scan of lymphedema,
used to determine surgical procedure.
• ivermectin- an antifilarial drug
•diethylcarbamazine- kills or impairs the reproduction of adult worms
•albendazole- currently used in a program of mass drug administration undertaken by the World Health
Organization in 1999 in an attempt to
IMAGE 22: Distribution of the drug albendazole,
currently used to treat lymphatic filariasis
eradicate the worms
Clinical trials of the common antibiotic doxycycline conducted by the Liverpool School of
Tropical Medicine have shown that it is an almost completely effective treatment. The
antibiotic kills the symbiotic Wolbachia bacteria that live inside the worms which then cause
the worms to die too. Further research on this treatment is being performed.
Surgical treatment can be helpful for hydrocele and related issues in the groin region, but it
is typically ineffective at correcting elephantiasis in other affected areas such as the limbs.
Another form of treatment involves thorough
cleaning of the affected areas. These rigorous
daily cleaning routines have been shown to
reduce and ease some symptoms of the
disease, helping to reduce disfigurement and
suffering.
IMAGE 23: A sonographic assessment of the effects of albendazole
and diethlycarbamazine on adult filarial worms and adjacent host
tissues; this subject had five filarial worm nests prior to treatment. A
and B show hydroceles present three months after treatment, and C
shows hydroceles still present at 24 months after treatment. So, it is
seen that the drugs used to treat lymphatic filariasis are effective at
killing the worms but not at removing the damage done to tissues as a
result of the disease.
Prevention . . .
Controlling mosquito population is fundamental in reducing the incidence of lymphatic filariasis.
Prevention of non-filarial elephantiasis consist of simple routines such as wearing shows (to avoid contact with irritant soil), hygienic acts of washing the
legs and feet with soap and water, daily soaking in antiseptic solution, and application of specific ointments.
Outlook . . .
Treatments for lymphatic filariasis depend on the geopgraphic location of the endemic area, a strategy called “geo-targetting” which is part of a larger goal
(expressed by the WHO) to eliminate the disease by 2020. Efforts thus far have been successful in reducing the occurrence of lymphatic filariasis. This
has not been as true for non-filaritic elephantiasis (podoconiosis) however, which has not yet been added to the list of Neglected Tropical Diseases.
Greater international awareness is needed before complete elimination is possible.
Research . . .
In 2007, a team of genetic researchers funded by the National Institute of Health (NIH), mapped the genome of Brugia malayi. Understanding the
genetic content of these worms may lead to the development of new drugs and/or a potential vaccine.
IMAGE 24
IMAGE 23
IMAGE 23: Hygiene and the simple act of
washing of the legs and feet can help prevent
non-filarial elephantiasis in regions where
potentially infected soil is present. IMAGE
24: A chart compiled by the WHO
showing those populations most at risk of
infection and thus targeted by the diseaseelimination program.
IMAGE 25: Brugia malayi, whose genome
was mapped by researchers in 2007. This
effort may lead to further developments and
a potential vaccine to prevent lymphatic
filariasis.
IMAGE 25
Summary and Conclusion
o
In this compendium we examined the various structures and functions of the lymphatic system. This included:
o
structural highlights of lymph vessels, lymph nodes and lymph fluid
o
immune and defense functions of the lymphatic system under normal conditions
o
what may result when the lymphatic system is no longer able to function normally: lymphedema
o
Then we examined the specific condition called lymphatic filariasis, or elephantiasis
o
The disease has filarial mosquito vector-borne origins and non-filarial origins
o
The most common form occurs when parasitic worms such as Brugia malayi invade and obstruct the lymphatic system
o
This leads to fibrosis, lymphangitis and lymphedema
o
Symptoms include abnormal enlargement of limbs and tissues, pain and progressive disability
o
The disease is incurable, though some treatments may help to control the symptoms and prevent further suffering. A common drug used
to combat elephantiasis is albendazole, which is currently being used by the WHO in a global attempt to eradicate the (filarial) disease.
This treatment is effective at killing the disease-causing parasites, but not at reducing/removing abnormal and pathologically affected
tissues. With the recent mapping of the parasitic worm’s genome, there is hope for a future vaccine.
o
This diagnostic image compendium would be complimented by further research and a secondary compendium that would do any of the
following:
ohistological and pathological comparisons of elephantiasis of filarial vs. non-filarial origin o
analyze the results of current drugs and treatment methods and compare effectiveness o
examine varying forms and variations of the disease in different endemic regions
o
o
o
introduce current research/development addressing elephantiasis and explore the possibilities of a future vaccine
outline the WHO’s elephantiasis elimination program . . . will lymphatic filariasis be eliminated by the stated goal of 2020?
The World Health Organization (WHO) website as well as that of the Center for Disease Control and Prevention (CDC) were helpful resources
in the formation of this compendium because they provide current, dependable and scientifically-based information. The Napa Valley College
Library website’s EBSCO document search was also helpful in providing peer-reviewed articles and journal documents written by medical
specialists, universities and research organizations. These presented much stronger and more professional references than what may have
been pulled from a simple internet search.
References
-Global Programme to Eliminate Lymphatic Filariasis
World Health Organization
http://whqlibdoc.who.int/hq/2002/WHO_CDS_CPE_CEE_2002.28.pdf
-Parasites-Lymphatic Filariasis Center for Disease Control and Prevention (CDC)
http://www.cdc.gov/parasites/lymphaticfilariasis/
-Elephatiasis Nostras Verrucosa Krisanne Sisto and Amor Khachemoune
American Journal of Clinical Dermatology, 2008; 9 (3)
-Lymphatic Filariasis USAID’s Neglected Tropical Disease Program
http://www.neglecteddiseases.gov/target_diseases/lymphatic_fillriasis/cycle.html
-Elephantiasis
Columbia Electronic Encyclopedia, 6th Edition
Database: Middle Search Plus: http://web.ebscohost.com/ehost/detail?hid=18&sid=8d5f28fc-405f-4404-bc413e50b9ce92c9%40sessionmgr14&vid=4&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=mih&AN=39004700
-Elephantiasis of non-filarial origin in the highlands of north–western Cameroon
Wanji, Tendongfor, Esum, Che, Mand, Tanga Mbi, Enyong and Hoerauf
Annals of Tropical Medicine & Parasitology, Vol. 102, No. 6, 529–540 (2008)
-Progress report on mass drug administration in 2009 World Health Organization
Weekly epidemiological record; 17 SEPTEMBER 2010, 85th YEAR; No. 38, 2010, 85, 365–372; http://www.who.int/wer
-The Function of Human Lymph Glands
SteadyHealth
http://www.steadyhealth.com/articles/The_function_of_human_lymph_glands_a38.html\
-Elephantiasis
WebMD
http://www.webmd.com/a-to-z-guides/elephantiasis
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