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PARTIAL FULFILMENT

IN

NCM 107-A 

DIAGNOSTIC PROCEDURE

OF

MAGNETIC RESONANCE IMAGING

(MRI)

&

CASE STUDY 

 ABOUT FILARIASIS

SUBMITTED BY:

SHEILLA MAE R. MOISES

SUBMITTED TO:

 AUREA CIELITO BATCHAR, RN, MAN, PHD

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MAGNETIC RESONANCE IMAGING

Magnetic resonance imaging (MRI) is one of the newest, and perhaps most

versatile, medical imaging technology available. Doctors can get highly refined

images of the body's interior without surgery using MRI. By using strong magnets

and pulses of radio waves to manipulate the natural magnetic properties in the

body, this technique makes better images of organs and soft tissues than those of 

other brain scanning technologies. MRI is particularly useful for imaging the brain

and spine, as well as the soft tissues of joints and the interior structure of bones, as

well as the liver. The entire body is visible with MRI, and the technique poses few

known health risks.

Purpose:

MRI is used to visualize the body to assist doctors in their efforts to diagnose

certain diseases or conditions and to evaluate injuries. For pediatric imaging, MRI

is used for a variety of purposes, including the following:

  diagnosing diseases of the central nervous system, including the brain and

spine

  detecting musculoskeletal disorders and injuries

  identifying complications of infectious diseases, such as those associated

with Lyme disease or acquired immunodeficiency syndrome (AIDS)

  imaging the cardiovascular system

  detecting congenital heart defects in neonates

  determining the stage of certain types of  cancer

  evaluating bone marrow disease

  assessing blood vessels in the brain for stroke and other abnormalities  assisting in the planning of surgery and cancer treatment

  evaluating the urinary tract

MRI provides images with excellent contrast that allow clinicians to clearly see

details of soft tissue, bone, joints, and ligaments. MRI angiography is an imaging

technique used to evaluate the blood vessels, for example, to detect aneurysms or

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cardiovascular problems. Because MRI does not use ionizing radiation to produce

images, like x ray and CT, it is often the examination of choice for pediatric

imaging and for imaging the male and female reproductive systems, pelvis andhips, and urinary tract and bladder.

MRI can also be used to evaluate brain function for assessing language, senses,

neurologic disorders, and pain . This technique, called functional MRI, involves

rapid imaging to display changes in the brain's blood flow in response to tasks or

visual and auditory stimuli. Functional MRI is being researched to image

neurologic disorders, such as attention deficit hyperactivity disorder (ADHD),

delayed cognitive development , and epilepsy.

MRI spectroscopy is another emerging imaging technique for evaluating pediatric

brain disorders. In MRI spectroscopy, chemicals in the brain are measured and

brain tissue is imaged. This technique is being investigated to evaluate traumaticbrain injury, speech delay, creatine deficiency syndromes, and mood disorders in

young children.

Interventional and intraoperative MRI is another developing field that involves

performing interventional procedures, primarily brain surgeries, using a specially

designed MRI unit in an operating room.

PREPARATION

You may be asked to wear a gown during the exam or you may be allowed to wearyour own clothing if it is loose-fitting and has no metal fasteners.

Guidelines about eating and drinking before an MRI exam vary with the specific

exam and also with the facility. For some types of exams, you will be asked to fast

for 8-12 hours. Unless you are told otherwise, you may follow your regular dailyroutine and take medications as usual.

Some MRI examinations may require the patient to swallow contrast material or

receive an injection of contrast into the bloodstream. The radiologist or

technologist may ask if you have allergies of any kind, such as allergy to iodine or

x-ray contrast material, drugs, food, the environment, or asthma. However, the

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contrast material most commonly used for an MRI exam, called gadolinium, doesnot contain iodine and is less likely to cause side effects or an allergic reaction.

The radiologist should also know if you have any serious health problems or if you

have recently had surgery. Some conditions, such as severe kidney disease may

prevent you from being given contrast material for an MRI. If there is a history of 

kidney disease, it may be necessary to perform a blood test to determine whether

the kidneys are functioning adequately.

Women should always inform their physician or technologist if there is any

possibility that they are pregnant. MRI has been used for scanning patients since

the 1980s with no reports of any ill effects on pregnant women or their babies.

However, because the baby will be in a strong magnetic field, pregnant women

should not have this exam unless the potential benefit from the MRI exam is

assumed to outweigh the potential risks. See the Safety page for more informationabout pregnancy and MRI. 

If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to

ask your physician for a prescription for a mild sedative prior to the scheduledexamination.

Jewelry and other accessories should be left at home if possible, or removed prior

to the MRI scan. Because they can interfere with the magnetic field of the MRI

unit, metal and electronic objects are not allowed in the exam room. These items

include:

   jewelry, watches, credit cards and hearing aids, all of which can be

damaged.

  pins, hairpins, metal zippers and similar metallic items, which can distort

MRI images.

  removable dental work.

  pens, pocketknives and eyeglasses.

  body piercings.

In most cases, an MRI exam is safe for patients with metal implants, except for afew types. People with the following implants cannot be scanned and should not

enter the MRI scanning area unless explicitly instructed to do so by a radiologist ortechnologist who is aware of the presence of any of the following:

  internal (implanted) defibrillator or pacemaker

  cochlear (ear) implant

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  some types of clips used on brain aneurysms

You should tell the technologist if you have medical or electronic devices in your

body, because they may interfere with the exam or potentially pose a risk,

depending on their nature and the strength of the MRI magnet. Examples includebut are not limited to:

  artificial heart valves

  implanted drug infusion ports

  implanted electronic device, including a cardiac pacemaker

  artificial limbs or metallic joint prostheses

  implanted nerve stimulators

  metal pins, screws, plates, stents or surgical staples

In general, metal objects used in orthopedic surgery pose no risk during MRI.However, a recently placed artificial joint may require the use of another imaging

procedure. If there is any question of their presence, an x-ray may be taken todetect the presence of and identify any metal objects.

Patients who might have metal objects in certain parts of their bodies may also

require an x-ray prior to an MRI. You should notify the technologist or radiologist

of any shrapnel, bullets, or other pieces of metal which may be present in your

body due to accidents. Dyes used in tattoos may contain iron and could heat up

during MRI, but this is rarely a problem. Tooth fillings and braces usually are not

affected by the magnetic field but they may distort images of the facial area orbrain, so the radiologist should be aware of them.

Infants and young children usually require sedation to complete an MRI exam

without moving. Moderate and conscious sedation can be provided at most

facilities. A physician or nurse specializing in the administration of sedation to

children will be available during the exam to ensure your child's safety while under

the effects of sedation. You will be given special instructions how to prepare your

child for the sedation.

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Nursing Interventions for MRI 

1.  Provide patient with comfort measures as needed.

2.  Tell the patient to resume his normal diet and activities unless otherwise

indicated.3.  Monitor vital signs.

4.  Monitor the patient for orthostatic hypotension. Assess vital signs before and

after testing

5.  Remove any metal items

6.  Request a lead apron to shield a fetus or vulnerable body parts

7.  Determine if the client is allergic to iodine

8.  Know location of emergency equipment

9.  Schedule iodine studies before the barium

10. Encourage large amounts of fluid to clear iodine

11. Check on bowel elimination for 2 days after barium studies

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PICTURES OF MAGNETIC RESONANCE IMAGING

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INTRODUCTION

Filiariasis is the name for a group of tropical diseases caused by various thread-likeparasitic round worms (nematodes) and their larvae. The larvae transmit the

disease to humans through a mosquito bite. Filariasis is characterized by fever, 

chills, headache, and skin lesions in the early stages and, if untreated, can progress

to include gross enlargement of the limbs and genitalia in a condition called

elephantiasis. 

Approximately 170 million people in the tropical and subtropical areas of southeast

Asia, South America, Africa, and the islands of the Pacific are affected by this

debilitating parasitic disease. While filariasis is rarely fatal, it is the second leading

cause of permanent and long-term disability in the world. The World Health

Organization (WHO) has named filariasis one of only six "potentially eradicable"infectious diseases and has embarked upon a 20-year campaign to eradicate the

disease.

In all cases, a mosquito first bites an infected individual then bites another

uninfected individual, transferring some of the worm larvae to the new host. Once

within the body, the larvae migrate to a particular part of the body and mature to

adult worms. Filariasis is classified into three distinct types according to the part of 

the body that becomes infected: lymphatic filariasis affects the circulatory system

that moves tissue fluid and immune cells (lymphatic system); subcutaneous

filariasis infects the areas beneath the skin and whites of the eye; and serous cavityfilariasis infects body cavities but does not cause disease. Several different types of 

worms can be responsible for each type of filariasis, but the most common species

include the following: Wucheria bancrofti, Brugia malayi (lymphatic filariasis),

Onchocerca volvulus, Loa loa, Mansonella streptocerca, Dracunculus medinensis 

(subcutaneous filariasis), Mansonella pustans, and Mansonella ozzardi (serous

cavity filariasis).

The two most common types of the disease are Bancroftian and Malayan filariasis,

both forms of lymphatic filariasis. The Bancroftian variety is found throughout

Africa, southern and southeastern Asia, the Pacific islands, and the tropical and

subtropical regions of South America and the Caribbean. Malayan filariasis occursonly in southern and southeastern Asia. Filariasis is occasionally found in the

United States, especially among immigrants from the Caribbean and Pacific

islands.

A larvae matures into an adult worm within six months to one year and can live

between four and six years. Each female worm can produce millions of larvae, and

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these larvae only appear in the bloodstream at night, when they may be

transmitted, via an insect bite, to another host. A single bite is usually not enough

to acquire an infection, therefore, short-term travelers are usually safe. A series of 

multiple bites over a period of time is required to establish an infection. As a result,

those individuals who are regularly active outdoors at night and those who spend

more time in remote jungle areas are at an increased risk of contracting the

filariasis infection.

Causes and symptoms

In cases of lymphatic filariasis, the most common form of the disease, the

disease is caused by the adult worms actually living in the lymphatic vessels near

the lymph nodes where they distort the vessels and cause local inflammation. In

advanced stages, the worms can actually obstruct the vessels, causing the

surrounding tissue to become enlarged. In Bancroftian filariasis, the legs and

genitals are most often involved, while the Malayan variety affects the legs below

the knees. Repeated episodes of inflammation lead to blockages of the lymphatic

system, especially in the genitals and legs. This causes the affected area to become

grossly enlarged, with thickened, coarse skin, leading to a condition called

elephantiasis.In conjunctiva filariasis, the worms' larvae migrate to the eye and can sometimes

be seen moving beneath the skin or beneath the white part of the eye (conjunctiva).

If untreated, this disease can cause a type of blindness known as onchocerciasis.

Symptoms vary, depending on what type of parasitic worm has caused the

infection, but all infections usually begin with chills, headache, and fever between

three months and one year after the insect bite. There may also be swelling,

redness, and pain in the arms, legs, or scrotum. Areas of pus (abscesses) may

appear as a result of dying worms or a secondary bacterial infection.

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Pathophysiology

The filarial life cycle, like that of all nematodes, consists of 5 developmental orlarval stages in a vertebral host and an arthropod intermediate host and vector.

Adult female worms produce thousands of first-stage larvae or microfilariae that

are ingested by a feeding insect vector. Some microfilariae have a unique daily

circadian periodicity in the peripheral circulation. The arthropod vectors,

mosquitoes and flies, also have a circadian rhythm in which they obtain blood

meals. The highest concentration of microfilariae usually occurs when the local

vector is feeding most actively.

Filariasis. This figure displays the life cycle of Wuchereria bancrofti inhumans and mosquito vectors (ie, Aedes, Anopheles, Culex, Mansonia species).

Life cycles of other lymphatic nematodes (ie, Brugia malayi, Brugia timori) are

identical, while the life cycles for other filariae differ in the body location of adult

worms, the microfilariae present, and the arthropod intermediate hosts and vectors.

Microfilariae then undergo two developmental changes in the insect. Third-stage

larvae then are inoculated back into the vertebral host during the act of feeding for

the final two stages of development. These larvae travel through the dermis and

enter regional lymphatic vessels. During the next 9 months, these develop intomature worms (20-100 mm in length). An average parasite can survive for about 5

years.

The prepatent period is defined as the interval between a vector bite and the

appearance of microfilaria in blood, with an estimated duration of about 12

months.

The following factors affect the pathogenesis of filariasis:

  The quantity of accumulating adult worm antigen in the lymphatics[5]

  The duration and level of exposure to infective insect bites[6]

  The number of secondary bacterial and fungal infections[5]

  The degree of host immune response[7]

Filarial infection generates significant inflammatory immune responses that

participate in the development of symptomatic lymphatic obstruction. Increased

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levels of immunoglobulin E (IgE) and immunoglobulin G4 (IgG4) secondary to

antigenic (from dead worms) stimulation of Th2-type immune response have been

demonstrated.

Studies have shown that there is a familial tendency to lymphatic obstruction,

providing support for the hypothesis that host genes influence lymphedema

susceptibility.[8]

Prenatal exposure seems to be an important determinant in

conferring greater immune tolerance to parasite antigen.[9]

Thus, individuals from

endemic areas are often asymptomatic until late in disease when they have high

worm burden, whereas nonimmune expatriates tend to have brisk immune

responses and more severe early clinical symptoms, even in light infections.

Recent studies have shown that lymphatic filarial parasites contain rickettsialike

Wolbachia endosymbiotic bacteria. This association has been recognized as

contributing to the inflammatory reaction seen in filariasis.[10]

Identification of microfilariae by microscopic examination is the most practical

diagnostic procedure. Examination of blood samples will allow identification of 

microfilariae of Wuchereria bancrofti, Brugia malayi and Brugia timori. It is

important to time the blood collection with the known periodicity of the

microfilariae. The blood sample can be a thick smear, stained with Giemsa or

hematoxylin and eosin.

Diagnosis of other filariasis diseases

  Examination of blood samples will allow identification of microfilariae of 

 Loa loa, Mansonella  perstans, and M. ozzardi.

  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

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Treatment

Either ivermectin, albendazole, or diethylcarbamazine is used to treat a filariasis

infection by eliminating the larvae, impairing the adult worms' ability to reproduce,

and by actually killing adult worms. Unfortunately, much of the tissue damage

may not be reversible. The medication is started at low doses to prevent reactions

caused by large numbers of dying parasites.

While effective, the medications can cause severe side effects in up to 70% of 

patients as a result either of the drug itself or the massive death of parasites in the

blood. Diethylcarbamazine, for example, can cause severe allergic reactions and

the formation of pusfilled sores (abscesses). These side effects can be controlled

using antihistamines and anti-inflammatory drugs (corticosteroids). Rarely,

treatment with diethylcarbamazine in someone with very high levels of parasite

infection may lead to a fatal inflammation of the brain (encephalitis). In this case,

the fever is followed by headache and confusion, then stupor and coma causedwhen massive numbers of larvae and parasites die. Other common drug reactions

include dizziness, weakness, and nausea.

Symptoms caused by the death of the parasites include fever, headache, muscle

pain, abdominal pain, nausea and vomiting, weakness, dizziness, lethargy, and

asthma. Reactions usually begin within two days of starting treatment and may last

between two and four days.

No treatment can reverse elephantiasis. Surgery may be used to remove surplus

tissue and provide a way to drain the fluid around the damaged lymphatic vessels.

Surgery may also be used to ease massive enlargement of the scrotum.

Elephantiasis of the legs can also be helped by elevating the legs and providing

support with elastic bandages.