The encyclopedia of arthritis

THE ENCYCLOPEDIA OF

ARTHRITIS

C. Michael Stein, M.D.

Guy Taylor, M.D.

The Encyclopedia of Arthritis

Copyright © 2004 by C. Michael Stein and Guy Taylor

All rights reserved. No part of this book may be reproduced or utilized in any form or by any means,

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Library of Congress Cataloging-in-Publication Data

Stein, C. Michael (Charles Michael)

The encyclopedia of arthritis / C. Michael Stein, Guy Taylor.

p.cm.

Includes bibliographical references and index.

ISBN 0-8160-4810-X

1. Arthritis—Encyclopedias. I. Taylor, Guy, M.D. II. Title.

RC933.S766 2004

616.7'22'003—dc21 2003040893

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This book is printed on acid-free paper.

CONTENTS

Preface vii

Introduction ix

Entries A–Z 1

Appendixes 295

Glossary 339

Bibliography 345

Index 353

T

his book is intended to provide educational infor￾mation to the public about arthritis and related

illnesses. It is not intended to substitute for any aspect

of medical care. The authors have made every effort

to provide information that is up-to-date, accurate,

and useful. However, the diagnosis and treatment of

the various conditions described and the monitoring

of patients must be performed by their physicians.

Readers should use the knowledge gained to work

with their physicians to optimize their medical care

and should not alter their medical care based on

information provided in this book.

PREFACE

vii

INTRODUCTION

ix

A

rthritis and related conditions affect millions of

people and cause pain, disability, and, for some

conditions, increased mortality. Arthritis is difficult

to understand because there are hundreds of differ￾ent arthritis-related conditions and many different

treatments for them. It is difficult to obtain accu￾rate, unbiased information because much of the

popular literature focuses on miracle cures. This

book sets out to provide concise and accurate infor￾mation about a wide range of arthritis-related top￾ics and to act as a comprehensive resource for

patients with arthritis, their families, and anyone

interested in understanding musculoskeletal illness.

Small-capital terms for arthritis and related con￾ditions in each section are cross-referenced in

the main text of entries. Drug names in small-cap￾ital letters are further detailed in Appendix I.

Finally, terms in small capitals relating to labora￾tory and diagnostic tests are expanded upon in

Appendix II. Occasionally, a reference to Appendix

I or to Appendix II appears following a term in the

main text.

ENTRIES A–Z

Achilles tendon This powerful tendon, some￾times called the heel cord, attaches the two major calf

muscles (gastrocnemius and soleus) to the calca￾neum (heel bone) and transmits the propulsive

forces needed for walking, running, and jumping.

The tendon is composed of spirals of collagen that

are wrapped into bundles forming a thick cord that

is both strong and able to stretch. Because of the

property of viscoelasticity, a sudden rapid muscle

contraction will find the tendon relatively stiff

while slower contractions allow greater stretch.

With repeated stretching, the tendon becomes more

flexible. Although this applies to all ages, maximum

flexibility does slowly decreases with increasing age.

The frequency of Achilles tendon injuries appears to

be increasing, with about 8 percent of top-level run￾ners having some Achilles problem each year.

Rupture of the achilles tendon The ability of

tendons to stretch and become more elastic during

use is the rationale for warming up before partici￾pating in sports. The typical Achilles tendon rupture

happens when a relatively untrained middle-aged

athlete plays a sport such as tennis and makes a

sudden forward movement. The rapid stretch of a

relatively stiff tendon can cause it to rupture and

the athlete feels sudden pain, as if kicked on the

back of the leg. He or she is unable to walk or stand

on tiptoes and may hear a pop as the tendon snaps.

The midtendon rupture of the Achilles is unusual

for a tendon. Like most tendons the Achilles is

nearly twice as strong as the muscles it joins.

Because of this, tendons normally tear in the area

where they join onto their muscle since this is the

weakest part. Therefore, for the midtendon to rup￾ture there is usually a preexisting abnormality that

has weakened it. The tendon may have been dam￾aged by previous trauma, TENDINITIS, long-term

corticosteroid use, local steroid injections into or

around the tendon, and other chronic medical ill￾nesses such as kidney failure. A few cases of tendon

rupture have been described in people taking

quinolone antibiotics, for example ofloxacin (see

DRUG-INDUCED RHEUMATIC DISEASE). The treatment of

a ruptured Achilles tendon can be either conserva￾tive, with the leg immobilized in a plaster cast for

about six weeks, or surgical, with open repair of

the tendon again followed by immobilization for

about six weeks. Surgical repair decreases the risk

that the tendon will rupture again from 10 percent

to 2 percent. However, surgery may not always be

the best option, particularly if the person has other

medical problems or is not athletic and is therefore

less likely to stress the tendon in the future.

Other conditions affecting the achilles tendon

Inflammation of the tendon at the point where it

joins bone is called enthesitis and is common in

ANKYLOSING SPONDYLITIS and REITER’S SYNDROME.

Treatment includes an orthotic shoe insert or a spe￾cial shoe designed to raise the heel, rest, ice, local

corticosteroid injection, and NSAIDs followed by

rehabilitation stretches.

Inflammation of the Achilles tendon (tendinitis)

occurs particularly in long-distance runners and

athletes involved in jumping sports or in those

using unsuitable footwear or having a biomechan￾ical problem. All these will place unusual or abnor￾mal stresses on the tendon. Tendinitis causes pain

in the area around the tendon, particularly when it

is stretched during activities such as walking or

running. The tendon is often visibly enlarged,

warm, and very tender to the touch. It can be very

difficult to decide whether the inflammation is

mostly in the tendon or around it (peritendinitis),

and both are often present. Sometimes the tendini￾tis occurs because of a partial tendon rupture, and

ultrasound scanning is excellent at showing this.

A

1

The treatment of Achilles tendinitis is similar to

that of enthesitis except that local steroid injections

near the middle of the tendon are avoided because

they may weaken the tendon and increase the

chance that it will rupture. Surgery to remove sur￾rounding inflamed tissue and chalky material from

within the tendon where it has degenerated is per￾formed if conservative treatment fails. This is suc￾cessful in 80 percent of competitive athletes.

If the person’s shoes or biomechanics of walking

or running are faulty, the condition may be cor￾rected with appropriate shoes. Bursae between the

skin and tendon and between the tendon and

underlying bone can become inflamed (see BURSITIS)

and cause symptoms similar to tendinitis. The treat￾ment of bursitis around the Achilles tendon is simi￾lar to that of tendinitis.

acne arthralgia Severe acne that causes cysts and

nodules on the buttocks, thighs, and upper arms as

well as in areas more usually affected by acne can

be associated with attacks of arthralgia and myalgia

that can last several weeks or months. Joint prob￾lems related to acne are rare and occur most often

in adolescent males. In addition to arthralgia and

myalgia, fever, loss of weight, and arthritis can

occur. The cause of this illness is not known, but it

may be a reaction to the bacteria that cause acne.

Treatment of the arthralgia is symptomatic with

NSAIDs and is combined with treatment to control

the acne. This can include long-term antibiotic

treatment, often with a tetracycline type of antibi￾otic, topical creams, retinoids, or in females, drugs

that block their male hormones (androgens) that

stimulate acne. Severe acne is occasionally compli￾cated by the SAPHO SYNDROME.

acquired immunodeficiency syndrome (AIDS)

See HUMAN IMMUNODEFICIENCY VIRUS.

acromegaly A syndrome due to excessive forma￾tion of growth hormone (GH) by a tumor in the

pituitary gland and characterized by coarse facial

features, enlargement of hands and feet, headache,

sweating, neuropathy, SLEEP APNEA, and muscu￾loskeletal symptoms. Acromegaly affects 40 to 60

people per million population.

Cause

An adenoma (a benign tumor) of the pituitary gland

that produces GH is the cause of acromegaly in 99

percent of patients. Other rare causes include tumors

of the gut, pancreas, and lung that produce GH.

Symptoms

Acromegaly results in gigantism if it develops in

children before puberty. More commonly, how￾ever, it develops slowly between the ages of 20 and

40 years. Symptoms may be due to either excessive

production of GH or pressure effects caused by the

adenoma itself. GH causes enlargement of the soft

tissues, resulting in a characteristic coarse facial

appearance with an enlarged jaw and tongue, sep￾aration of the teeth, and large hands and feet. Be￾cause of this, unrelated patients with acromegaly

are said to look more like each other than like any

of their family members. Internal organs such as

the heart, liver, and kidneys also enlarge. Hyper￾tension (30 percent) and diabetes (20 percent) are

common. If the adenoma in the pituitary enlarges,

it can cause pressure effects in the brain. The optic

nerves that run from the eye to the brain pass

very close to the pituitary gland. If the adenoma

presses on an optic nerve, it can cause partial blind￾ness. The tumor can also affect normal pituitary tis￾sue and cause reduced production of some

hormones, for example gonadotrophins (hormones

that regulate the release of sex hormones) and

increased production of others, for example pro￾lactin, a hormone that regulates the secretion of

breast milk.

Musculoskeletal symptoms Bone and joint

problems develop in at least 50 percent of patients

with acromegaly. Initially the cartilage in the joints

increases in amount, and the capsule of the joint

and the ligaments close to it soften and thicken,

resulting in hypermobility. Later degenerative

changes develop in joints perhaps because of the

altered biomechanics caused by the changes in car￾tilage and soft tissues. The arthritis associated with

acromegaly causes pain, stiffness, and reduced

range of movement, as happens in OSTEOARTHRITIS

of any cause. The fingers, spine, and knees are com￾monly involved, and the shoulders, elbows, and

ankles are affected more frequently than occurs in

the usual type of osteoarthritis. OSTEOPOROSIS may

2 acne arthralgia

develop because of reduced sex hormone produc￾tion as well as increased loss of calcium in the urine.

CARPAL TUNNEL SYNDROME is common because the

median nerve runs through a narrow tunnel in the

wrist, and if the soft tissues increase in size, as hap￾pens in acromegaly, it causes pressure on the nerve

and the symptoms of carpal tunnel syndrome. Sim￾ilarly, other nerves that run through narrow chan￾nels can become trapped by soft tissue, resulting in

neuropathy.

Premature coronary artery disease, heart failure,

and sleep apnea all contribute to the increased mor￾tality rate in people with acromegaly. The mortality

rate in untreated acromegaly is twice that of the

general population. However, if treatment is suc￾cessful in reducing GH levels in the blood to less

than 5 mU/L, there is no increased risk of death.

The concentration of calcium in the blood is ele￾vated (hypercalcemia) in 5 percent of patients, and

the increased excretion of calcium in the urine can

increase the risk of developing kidney stones. The

osteoarthritis that often accompanies acromegaly

may cause considerable pain and disability, and

there is an increased risk of CALCIUM PYROPHOSPHATE

DIHYDRATE DEPOSITION DISEASE and pseudogout. A

large pituitary tumor can cause permanent loss of

vision, particularly peripheral vision.

Diagnosis

The characteristic appearance of the face and hands

usually prompts the diagnosis. X rays can support

the diagnosis, showing characteristic tufting of the

bones at the ends of the fingers. Other X ray

changes include widened joint spaces (because of

the increased amount of cartilage) and typical

changes of osteoarthritis. They include the forma￾tion of osteophytes sometimes occurring in joints

such as shoulders and elbows, which are not usu￾ally affected by osteoarthritis. In the spine the

X rays have an appearance similar to that of DISH.

Blood tests such as elevated levels of GH or

somatomedin C are useful for making the diagno￾sis. Abnormalities of other pituitary hormones such

as prolactin or gonadotrophins may be found but

are not specific. An MRI scan is useful because the

pituitary adenoma can often be seen. Eye tests may

show loss of peripheral vision that the patient had

not noticed.

Treatment and Outcome

The aim of treatment is to relieve symptoms of

acromegaly, reduce GH levels to less than 5 mU/L,

treat the local pressure effects of the tumor, and

maintain normal pituitary function. The treatment

of choice, transsphenoidal surgery, achieves a cure

rate of between 40 and 90 percent. Radiotherapy

may be used to treat the tumor in patients who are

not healthy enough to undergo surgery or those

who choose not to have it. After treatment with

radiotherapy the GH levels decline slowly over a

few years, and with time there is an increased

chance that production of other pituitary hor￾mones will also decline.

Treatment of acromegaly with drugs such as

octreotide and bromocriptine decreases GH pro￾duction. These drugs are used when GH levels

remain raised after surgery or radiotherapy or

sometimes as the only therapy in elderly patients

who prefer not to undergo surgery or radiotherapy.

Joint symptoms are treated with analgesics,

NSAIDs, and physical therapy as appropriate. Sur￾gical removal of large osteophytes is sometimes

helpful, and total joint replacement may become

necessary if a hip or knee joint is badly affected.

The symptoms caused by carpal tunnel syndrome

improve with adequate control of GH levels, but

those caused by arthritis do not.

acupuncture People with arthritis frequently use

complementary and alternative therapies such as

acupuncture, an ancient Chinese art that seeks to

correct imbalances in the flow of energy by select￾ing appropriate acupuncture points for stimulation.

Such stimulation often involves the puncturing of

the skin with needles. However, practitioners can

also use needle manipulation, heat, pressure, suc￾tion, and electrical current to stimulate the chosen

points. The concept of yin and yang is the most

important theory in traditional Chinese medicine. It

claims that all things have two aspects, yin and

yang, that are at the same time both opposite and

dependent on each other. They are in a constant

state of change and balance. Disease results from

loss of this balance, and treatment is directed at

restoring it. Qi is the life force that governs the func￾tions of the organs and flows through meridians or

channels to all parts of the body. Pain results from

acupuncture 3

disturbances of this flow. Several types of acupunc￾ture practice may be found in the Western world.

• Traditional Chinese acupuncture is based on tra￾ditional diagnoses and aims at restoring yin and

yang and normal qi flow.

• Cookbook acupuncture consists of techniques

borrowed from Chinese acupuncture but used to

treat disorders based on a Western medical diag￾nosis. An example is the commonly used auricu￾lar acupuncture to help with smoking cessation.

A small but increasing number of Western med￾ical practitioners are using this type of acupunc￾ture as well as trigger point acupuncture.

• Trigger point acupuncture is used to relieve mus￾culoskeletal pain. The trigger points so often

found in FIBROMYALGIA have been scientifically

studied in the West only in the past 70 years. As

long ago as 600 B.C. the Chinese were inserting

needles into these ah shi (ah yes) points.

• Scientific acupuncture is based on modern sci￾entific interpretations of the physiological effects

of traditional methods.

The insertion of the needles is not particularly

painful. However, for maximum benefit a needling

sensation should be felt. This is variously described

as dull, aching, heavy, sore, distending, or warm,

and it may travel away from the needle site. Patients

may feel relaxed afterward and can get quite drowsy

and occasionally euphoric, presumably as a result of

endorphin release. An average treatment involves

five to 10 sessions, and most acupuncturists con￾tinue treatment until the patient is cured or no fur￾ther improvement occurs.

Determining if acupuncture is useful for the

treatment of arthritis has been difficult. Clinical tri￾als examining the effectiveness of acupuncture for

the treatment of rheumatological problems have

been criticized because the number of patients stud￾ied was often small and because it was difficult to

control for a placebo effect occurring in response to

the needles (see CLINICAL TRIAL). Some studies have

tried to overcome this criticism by using needles to

stimulate sham or placebo points that should not

result in benefits and then comparing these results

with those of active acupuncture. There has, how￾ever, been disagreement whether a nonacupunc￾ture type of treatment or acupuncture at a sham

point is the most appropriate control group.

There are few well-designed studies, and some

have shown a small improvement in pain in patients

with OSTEOARTHRITIS and fibromyalgia. Several trials

have shown modest benefits in treating particularly

troublesome joints in RHEUMATOID ARTHRITIS. The

risks from acupuncture are small, provided that nee￾dles are adequately sterilized and are not inserted

into a nerve, vital organ, or artery. Puncture of the

lung (pneumothorax), transmission of HEPATITIS B or

HEPATITIS C, nerve damage, and bleeding are uncom￾mon complications.

adult-onset Still’s disease See JUVENILE ARTHRITIS.

Alexander technique This technique was devel￾oped by an actor, F. M. Alexander, to improve his

voice. He believed that the way we breathe affects

the function of our bodies and that the relationship

between the head, neck, and upper body are the pri￾mary controls of posture. Abnormal posture causes

abnormal muscular tension in one muscle group

and can adversely affect the whole body. Treatment

with the Alexander technique usually involves indi￾vidual or group lessons during which a teacher

observes the posture and tension in a student. The

teacher then explains, using touch and instructions,

more efficient posture, movement, and breathing.

The Alexander technique has not been adequately

evaluated in well-designed studies. Apart from anec￾dotal experience, little scientific evidence is available

with which to evaluate the Alexander technique as

a therapy for arthritis-related problems.

alkaptonuria (ochronosis) This rare, inherited defi￾ciency of the enzyme homogentisic acid oxidase

results in homogentisic acid reaching high levels in

the body. This acid is excreted in the urine, which

will then turn black if left to stand for a while because

the acid oxidizes. The diagnosis of alkaptonuria is

suspected if a person gives a history of passing dark

urine or of urine that becomes dark after standing for

a while. Pigmented or dark-colored deposits of

homogentisic acid collect in tissues such as cartilage

that are rich in collagen, an important component of

joints and soft tissues. These pigmented deposits are

4 adult-onset Still’s disease