Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever
What Is Rocky Mountain Spotted Fever?
What Are the Infection’s Signs and Symptoms?
How Do Doctors Diagnose Rocky Mountain Spotted Fever?
What Medical Complications Can Occur?
How Can Rocky Mountain Spotted Fever Be Prevented?
Rocky Mountain spotted fever is an infection transmitted by the bite of a tick*. At first its symptoms are mild, but without treatment the disease can become serious and cause organ damage and death.
- *tick
- is a small blood-sucking creature that may transmit disease-causing germs from animals to humans through its bite.
KEYWORDS
for searching the Internet and other reference sources
Ixodidae ticks
Rickettsia rickettsii
Rickettsial infections
Zoonoses
What Is Rocky Mountain Spotted Fever?
Rocky Mountain spotted fever (RMSF) is the most serious of the rickettsial (rih-KET-see-ul) infections, diseases caused by bacteria from the Rickettsiaceae family. These bacteria typically spread to people through blood-sucking parasites* such as ticks and fleas. In Rocky Mountain spotted fever, the bacterium Rickettsia rickettsii lives and reproduces in the Ixodidae (ik-SAH-dih-day) family of hard-bodied ticks, such as the American dog tick and the Rocky Mountain wood tick, before it infects people. Once it does infect a person, it enters cells lining the blood vessels and can cause serious disease.
- *parasites
- (PAIR-uh-sites) are organisms such as protozoa (one-celled animals), worms, or insects that must live on or inside a human or other organism to survive.
Several of the disease’s first symptoms can be confused with those of other infections. As the condition grows worse, it often causes a widespread rash, which led people to call RMSF “black measles” when it was described in the late nineteenth century. If the infection is not treated, it can damage several organ systems and sometimes lead to death.
How Common Is It?
Despite its name, the infection is not limited to the Rocky Mountains. It is found throughout the United States, and most cases actually occur in the southeastern part of the country. The disease also has been found in southern Canada, Mexico, some countries in Central America, and parts of South America. According to the U.S. Centers for Disease Control and Prevention, between 250 and 1,200 cases are reported in the United States each year, with most in children under the age of 15. About 5 percent of Rocky Mountain spotted fever cases are fatal, usually because a person does not receive treatment quickly.
Is It Contagious?
RMSF is not contagious from person to person. It can spread only from a tick to a person, usually through the tick’s bite when it feeds. Rarely, people can become infected when they come into contact with tick droppings or dead ticks that have been crushed. The bacterium lives in the tick and survives from one generation of the parasite to the next. Female ticks can pass it to their eggs, and male ticks can pass it to females when they mate.
What Are the Infection’s Signs and Symptoms?
Symptoms of infection include severe headache, fever, confusion, chills, nausea (NAW-zee-uh), vomiting, loss of appetite, and muscle pain. Many infections have these symptoms, so they may not be immediately identified as RMSF. As the disease worsens, it may cause joint pain, abdominal* pain, extreme thirst, hallucinations*, diarrhea (dye-uh-REE-uh), and a rash. The rash usually appears 3 to 6 days after the start of symptoms. It typically starts as small, pink spots that crop up on the wrists, lower part of the arms, and ankles. The rash does not itch, and over time the spots become raised. In many patients, a red, spotted rash develops that looks like dots of blood under the skin, often on the palms of the hands and the soles of the feet. Even though this rash is one of the most distinctive symptoms, it is not seen in every patient. As many as 10 percent to 20 percent of patients do not have the typical rash.
- *abdominal
- (ab-DAH-mih-nul) refers to the area of the body below the ribs and above the hips that contains the stomach, intestines, and other organs.
- *hallucinations
- (ha-loo-sin-AY-shuns) occur when a person sees or hears things that are not really there. Hallucinations can result from nervous system abnormalities, mental disorders, or the use of certain drugs.
How Do Doctors Diagnose Rocky Mountain Spotted Fever?
Doctors usually identify the infection based on symptoms seen during an examination, reports of the disease in the area, and knowledge of a recent tick bite. Fever, rash, and history of a tick bite are considered the classic features of RMSF. The doctor also may take a blood sample to look for antibodies* to the bacteria.
- *antibodies
- (AN-tih-bah-deez) are protein molecules produced by the body’s immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.
What Is the Treatment?
People with RMSF often need to be in the hospital, where they can receive supportive care. The disease is treated with antibiotics, which are given as soon as a doctor suspects that a patient might have RMSF. Waiting until laboratory tests confirm the diagnosis could put the patient at greater risk, because the infection can progress so quickly. Patients continue taking the medicine for at least 3 days after the fever goes away.
What Medical Complications Can Occur?
Treatment typically takes 5 to 10 days, but it can last much longer. Without treatment or with delayed treatment, severe cases of illness can lead to death. In addition, the disease can cause problems with the central nervous system*, the kidneys, the digestive system*, and the respiratory tract*. This can lead to partial paralysis*, hearing loss, meningitis*, heart failure, brain damage, kidney failure, and shock*.
- *central nervous
- (SEN-trul NER-vus) system is the part of the nervous system that includes the brain and spinal cord.
- *digestive system
- is the system that processes food. It includes the mouth, esophagus, stomach, intestines, colon, and rectum and other organs involved in digestion, including the liver and pancreas.
- *respiratory tract
- includes the nose, mouth, throat, and lungs. It is the pathway through which air and gases are transported down into the lungs and back out of the body.
- *paralysis
- (pah-RAH-luh-sis) is the loss or impairment of the ability to move some part of the body.
- *meningitis
- (meh-nin-JY-tis) is an inflammation of the meninges, the membranes that surround the brain, and the spinal cord. Meningitis is most often caused by infection with a virus or a bacterium.
- *shock
- is a serious condition in which blood pressure is very low and not enough blood flows to the body’s organs and tissues. Untreated, shock may result in death.
How Can Rocky Mountain Spotted Fever Be Prevented?
It is important to take precautions to limit the risk of tick bites: for example, by avoiding walks through brush and dense vegetation in areas with lots of ticks. When a person spends time outside, it is a good idea to wear long pants, long sleeves, and socks, with the pants tucked into the socks. Light-colored clothing makes ticks easier to see, and insect repellent can protect exposed skin. After being outside in tick-infested areas, it is wise to remove clothing and check the body, including the hair, thoroughly for the parasites. Doctors recommend that any ticks that are found be removed right away; the longer the tick stays attached, the greater the chance that the RMSF bacterium can enter the body.
Dr. Ricketts
Even if you have heard about Rocky Mountain spotted fever, you may not know the name Howard T. Ricketts. Dr. Ricketts discovered the bacterium behind the disease and figured out that it spreads to people through tick bites. In recognition of that work, Rickettsia rickettsii, the RMSF bacterium, received its double Ricketts name. Dr. Ricketts also did research on typhus (TY-fis), another rickettsial infection. He died of typhus in 1910.
See also
Ehrlichiosis
Rickettsial Infections
Tick-borne Infections
Zoonoses
Resources
Organization
U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. The CDC provides a fact sheet and other information on rickettsial infections.
Telephone 800-311-3435 http://www.cdc.gov
Website
KidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including Rocky Mountain spotted fever.
Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever
Disease History, Characteristics, and Transmission
Introduction
Rocky Mountain spotted fever is a bacterial disease caused by Rickettsia rickettsii. This bacterium causes holes in blood vessels, which allows to blood leak into tissues and organs, causing damage to these areas. Humans become infected with Rocky Mountain spotted fever following a bite from an infected tick. Infection can also occur following contact with the blood or feces of infected ticks. Rocky Mountain spotted fever is present in most of the United States and has a yearly infection rate of about 800 cases. It is also found in some regions in South America. Similar strains of Rickettsia bacteria cause spotted fevers worldwide.
This disease usually results in fever, nausea, vomiting, headache, muscle aches, lack of appetite, diarrhea, abdominal pains, and, in some cases, a characteristic red rash. While recovery is likely for patients who receive early treatment, delayed treatment can result in complications, including death. Treatment involves a course of antibiotics for the duration of the fever. Since there is no vaccine available, the best prevention method is avoidance of ticks. This reduces the chance that a tick bite will lead to transmission of R. rickettsii.
Disease History, Characteristics, and Transmission
Rocky Mountain spotted fever was first identified as a tick-borne bacterial disease by Howard T. Ricketts (1871–1910) shortly before his death. Prior to its identification, this disease was first recognized in 1896 in the Snake River Valley of Idaho where it affected hundreds of people and was often fatal. Although it was first found in the Rocky Mountains, this disease occurs all over the United States, except for Hawaii, Vermont, Maine, and Alaska. Rocky Mountain spotted fever is a potentially fatal disease, and prior to 1940, had a mortality rate of 30%. This rate decreased to 3–5% following introduction of an effective antibiotic treatment.
WORDS TO KNOW
ACARACIDES: A chemical that kills mites and ticks is an acaracide.
TICK: A tick is any blood-sucking parasitic insect of suborder Ixodides, superfamily Ixodoidea. Ticks can transmit a number of diseases, including Lyme disease and Rocky Mountain spotted fever.
VECTOR: Any agent, living or otherwise, that carries and transmits parasites and diseases. Also, an organism or chemical used to transport a gene into a new host cell.
Rocky Mountain spotted fever is caused by the bacterium Rickettsia rickettsii. Infection occurs when a tick vector bites an infected animal and then bites a human. Infection can also occur if human skin is contaminated with tick blood or feces. The most common ticks to spread this infection to humans are the American dog tick (Dermacentor variabilis) and the Rocky Mountain wood tick (Dermacentor andersoni). R. rickettsii lives and reproduces within cells lining blood vessels. The bacteria cause cell death, which leads to gaps forming in the surface of the blood vessel. Blood leaks through these gaps into surrounding tissue and causes tissue and organ damage. Blood leakage also causes a red rash that is present in some cases.
Various symptoms may arise over the course of a week. Initial symptoms include fever, nausea, vomiting, headache, muscle aches, and lack of appetite. A faint rash may also appear within 2–5 days after fever. Later symptoms include abdominal pain, joint pain, and diarrhea. In addition, usually around six days after the onset of fever, a red, spotted rash occurs in 35–60% of patients. Complications can arise in patients suffering severe cases when the respiratory, central nervous, gastrointestinal, and renal systems are affected. Long-term effects of Rocky Mountain spotted fever can include paralysis, amputation of limbs due to gangrene, loss of hearing and bowel or bladder control, and development of movement disorders.
Scope and Distribution
Rocky Mountain spotted fever occurs in almost all regions of the United States. It is dominant in the south-Atlantic regions, particularly in North Carolina. This fever also occurs in South America, particularly in Argentina, Brazil, Colombia, Costa Rica, Panama and, also, in Mexico. Bacterial strains (types) closely related to Rickettsia rickettsii also cause spotted fevers worldwide. The type of Rickettsia bacterium present in a region determines which type of spotted fever occurs in the area.
In the United States, the Centers for Disease control and Prevention (CDC) recorded 250–1,200 cases of Rocky Mountain spotted fever annually from 1955 to 2005. This fever predominantly occurs during warm weather when ticks are more active. The summer months in the United States, from April through to September, mark the highest levels of infection throughout the year.
All people can potentially contract Rocky Mountain spotted fever. However, males, Caucasians, and children are infected most often. Increased exposure to ticks increases the likelihood of infection. Therefore, people who live with dogs or people who reside near tick-inhabited areas, such as woodlands, are at risk of infection.
Treatment and Prevention
A course of antibiotics is used to treat Rocky Mountain spotted fever. Doxycycline is recommended by the CDC as an effective drug to eradicate this infection. However, for pregnant women, chloramphenicol should be used as an alternative to doxycycline, since doxycycline is associated with the risk for malformations of the teeth and bones in unborn children. Treatment administered immediately provides the best results. Fever usually subsides within 1–3 days following antibiotic treatment given within 4–5 days after the onset of the disease. However, recovery from fever will take longer in patients who receive treatment later, or who are suffering a severe illness.
There is no vaccine available for Rocky Mountain spotted fever. Therefore, the best prevention method is to avoid contact with ticks. This can be achieved in several ways. Areas inhabited by ticks, such as long grasslands and woodlands, may be avoided. If these areas can't be avoided, repellents on clothing or skin can help repel ticks and prevent them from biting. In addition, protective clothing, such as long-sleeved shirts, boots, and hats, can be worn to prevent ticks coming in contact with the skin. It is also important to thoroughly check the body for ticks following any activity in tick habitats. This may prevent ticks from biting, or, in the cases when ticks have already attached to the skin, will ensure early removal and reduce the chances of infection.
Large-scale prevention methods include the use of acaricides (insecticides that kill ticks) in tick-infested areas in order to reduce the number of ticks. If there are fewer ticks in an area, it is less likely that humans will be bitten.
Impacts and Issues
Rocky Mountain spotted fever is a potentially life threatening disease. Late diagnosis and delayed treatment increase the chances of complications, such as kidney failure and even death. As this disease infects approximately 800 people a year in the United States and is potentially fatal, increased awareness and reminders about prevention are recommended by the Directors of Health Promotion and Education.
This disease can be difficult to diagnose during the initial stages due to its wide range of symptoms and the fact that not all cases exhibit the characteristic red rash. This is a problem, since late diagnosis increases the chances of severe complications and possible fatalities. To address this problem, treatment is usually given before conclusive evidence confirms the disease. This approach ensures that patients with the disease receive treatment as soon as possible.
Despite prevention methods, such as the use of aracicides, the wearing of protective clothing, and the use of repellents, ticks can still come in contact with humans. When people find ticks on their bodies, removal is vital, and the earlier it is done, the less chance there is of infection. However, incorrect removal of ticks can cause complications. If the mouthparts of the tick remain in the body, infection can still occur. Furthermore, handling ticks with bare hands also increases the risk of exposure as infection can occur when blood or feces come in contact with open skin. The best technique for removing a tick involves grabbing the tick with tweezers as close to the skin as possible and pulling it away from the skin. Coating ticks with petroleum jelly or burning them with a match are not effective techniques for tick removal, despite the popularity of these methods with the general public.
See AlsoBacterial Disease; Rickettsial Disease; Zoonoses.
BIBLIOGRAPHY
Books
Mandell, G. L., J. E. Bennett, and R. Dolin. Principles and Practice of Infectious Diseases. 6th ed. Philadelphia: Elsevier, 2004.
Periodicals
Parola, P., C. D. Paddock, and D. Raoult. “Tick-Borne Rickettsioses Around the World: Emerging Diseases Challenging Old Concepts.” Clinical Microbiology Reviews 18 (October 2005): 719–756. Also available online at <http://cmr.asm.org/cgi/content/full/18/4/719>.
Web Sites
Centers for Disease Control and Prevention. “Rocky Mountain Spotted Fever.” May 20, 2005. <http://www.cdc.gov/ncidod/dvrd/rmsf/index.htm> (accessed March 6, 2007).
Directors of Health Promotion and Education. “Rocky Mountain Spotted Fever.” <http://www.astdhpphe.org/infect/rms.html> (accessed March 6, 2007).
Illinois Department of Public Health. “Rocky Mountain Spotted Fever.” <http://www.idph.state.il.us/public/hb/hbrmsf.htm> (accessed March 6, 2007).
Rocky Mountain Spotted Fever
Rocky Mountain spotted fever
Definition
Rocky Mountain spotted fever (RMSF) is a tick-borne illness caused by a bacteria, resulting in a high fever and a characteristic rash.
Description
The bacteria causing RMSF is passed to humans through the bite of an infected tick. The illness begins within about two weeks of such a bite. RMSF is the most widespread tick-borne illness in the United States, occurring in every state except Alaska and Hawaii. The states in the south-Atlantic region, (Delaware, Maryland, Washington DC, Virginia, West Virginia, North Carolina, South Carolina, Georgia, and Florida) have a great deal of tick activity during the spring and summer months, and the largest number of RMSF cases come from those states. About 5 percent of all ticks carry the causative bacteria.
Demographics
About 90 percent of all cases of RMSF occur between the months of April and September. Children under the age of 15 years have the majority of RMSF infections (about 66% of all infections). The peak incidence of RMSF occurs in five to nine year old children, with boys more likely to be infected than girls. A higher risk of infection seems to occur in individuals who spend time with dogs or who live near wooded or grassy areas.
Causes and symptoms
The bacterial culprit in RMSF is Rickettsia rickettsii. It causes no illness in the tick carrying it and can be passed on to the tick's offspring. When a tick attaches to a human, the bacteria are passed. The tick must be attached to the human for about six hours for this passage to occur. Although prompt tick removal will cut down on the chance of contracting RMSF, removal requires great care. If the tick's head and body are squashed during the course of removal, the bacteria can be inadvertently rubbed into the tiny bite wound.
Symptoms of RMSF begin within two weeks of the bite of the infected tick. Symptoms usually begin suddenly, with high fever, chills, headache , severe weakness, and muscle pain . Pain in the large muscle of the calf is very common, and may be particularly severe. The patient may be somewhat confused and delirious. Without treatment, these symptoms may last two weeks or more.
The rash of RMSF is quite characteristic. It usually begins on the fourth day of the illness and occurs in at least 90 percent of all patients with RMSF. It starts around the wrists and ankles, as flat pink marks (called macules). The rash spreads up the arms and legs, toward the chest, abdomen, and back. Unlike rashes that accompany various viral infections, the rash of RMSF does spread to the palms of the hands and the soles of the feet. Over a couple of days, the macules turn a reddish-purple color. In this new stage they are called petechiae, which are tiny areas of bleeding under the skin (pinpoint hemorrhages). Over the next several days, the individual petechiae may spread into each other, resulting in larger patches of hemorrhage.
The most severe effects of RMSF occur due to damage to the blood vessels, which become leaky. This action accounts for the production of petechiae. As blood and fluid leak out of the injured blood vessels, other tissues and organs may swell and become damaged. Other symptoms that may occur are as follows:
- breathing difficulties as the lungs are affected
- heart rhythms abnormal
- kidney failure in very ill patients
- liver function decrease
- nausea, vomiting , abdominal pain, and diarrhea
- brain inflammation (encephalitis ) in about 25 percent of RMSF patients (Brain injury can result in seizures, changes in consciousness, actual coma, loss of coordination, imbalance on walking, muscle spasms , loss of bladder control, and various degrees of paralysis.)
- the clotting system impaired and blood evident in the stools or vomit
Diagnosis
Diagnosis of RMSF is almost always made on the basis of the characteristic symptoms, coupled with either a known tick bite (noted by about 60 to 70 percent of patients) or exposure to an area known to harbor ticks. Complex tests exist to determine conclusively the diagnosis of RMSF, but these are performed in only a few laboratories. The results of these tests take so long to obtain that they are seldom used; delaying treatment is the main cause of death in patients with RMSF.
Treatment
It is essential to begin treatment absolutely as soon as RMSF is seriously suspected. Delaying treatment can result in death.
Antibiotics are used to treat RMSF. The first choice is doxycycline; the second choice is chloramphenicol. If the patient is well enough, treatment by oral intake of medicine is perfectly effective. Sicker patients may need to be given the medication through a needle in the vein (intravenously). Penicillin and sulfa drugs are not suitable for treatment of RMSF, and their use may increase the death rate by delaying the use of truly effective medications.
Very ill patients need to be hospitalized in an intensive care unit. Depending on the types of complications a particular patient experiences, a variety of treatments may be necessary, including intravenous fluids, blood transfusions, anti-seizure medications, kidney dialysis, and mechanical ventilation (a breathing machine).
Prognosis
Prior to the regular use of antibiotics to treat RMSF, the death rate was about 25 percent. Although the death rate from RMSF has improved greatly with an understanding of the importance of early use of antibiotics, there is still a 5 percent death rate. This rate is believed to be due to delays in the administration of appropriate medications.
Certain risk factors suggest a worse outcome in RMSF. Death rates are higher in males and increase as people age. It is considered a bad prognostic sign to develop symptoms of RMSF within only two to five days of a tick bite.
Prevention
The mainstay of prevention involves avoiding areas known to harbor ticks. However, because many people enjoy recreational activities in just such areas, the following preventative steps can be taken:
- wearing light colored clothing (so that attached ticks are more easily noticed)
- wearing long sleeved shirts and long pants and tucking pant legs into socks
- spraying clothing with appropriate tick repellents
- examining oneself (Anybody who has been outside for any amount of time in an area known to have a population of ticks should examine his or her body carefully for ticks. Parents should examine their children at the end of the day.)
- removing any ticks using tweezers, so that infection does not occur due to handling the tick. (Parents should grasp the tick's head with the tweezers and pull gently but firmly so that the head and body are entirely removed.)
- keeping areas around homes clear of brush, which may serve to harbor ticks
Parental concerns
When children have been playing outside, it is important to carefully examine them for ticks when they come indoors. Rapidly yet carefully removing any ticks may help prevent or decrease the injection of infection-causing material. Dogs that are kept as family pets should also be examined for the presence of ticks and treated regularly with tick-killing products.
KEY TERMS
Encephalitis —Inflammation of the brain, usually caused by a virus. The inflammation may interfere with normal brain function and may cause seizures, sleepiness, confusion, personality changes, weakness in one or more parts of the body, and even coma.
Macule —A flat, discolored area on the skin.
Petechia —Plural, petechiae. A tiny purple or red spot on the skin resulting from a hemorrhage under the skin's surface.
Resources
BOOKS
Dumler, J. Stephen. "Spotted Fever Group Rickettsioses." In Nelson Textbook of Pediatrics. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2004.
Paddock, Christopher D., and James E. Childs. "Rickettsia rickettsii (Rocky Mountain Spotted Fever)." In Principles and Practice of Pediatric Infectious Diseases, 2nd ed. Edited by Sarah S. Long et al. St. Louis, MO: Elsevier, 2003.
ORGANIZATIONS
Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. Web site: <www.cdc.gov>.
Rosalyn Carson-DeWitt, MD
Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever
Definition
Rocky Mountain spotted fever (RMSF) is a tick-borne illness caused by a bacteria, resulting in a high fever and a characteristic rash.
Description
The bacteria causing RMSF is passed to humans through the bite of an infected tick. The illness begins within about two weeks of such a bite. RMSF is the most widespread tick-borne illness in the United States, occurring in every state except Alaska and Hawaii. The states in the mid-Atlantic region, the Carolinas, and the Virginias have a great deal of tick activity during the spring and summer months, and the largest number of RMSF cases come from those states. About 5% of all ticks carry the causative bacteria. Children under the age of 15 years have the majority of RMSF infections.
Causes and symptoms
The bacterial culprit in RMSF is called Rickettsia rickettsii. It causes no illness in the tick carrying it, and can be passed on to the tick's offspring. When a tick attaches to a human, the bacteria is passed. The tick must be attached to the human for about six hours for this passage to occur. Although prompt tick removal will cut down on the chance of contracting RMSF, removal requires great care. If the tick's head and body are squashed during the course of removal, the bacteria can be inadvertently rubbed into the tiny bite wound.
Symptoms of RMSF begin within two weeks of the bite of the infected tick. Symptoms usually begin suddenly, with high fever, chills, headache, severe weakness, and muscle pain. Pain in the large muscle of the calf is very common, and may be particularly severe. The patient may be somewhat confused and delirious. Without treatment, these symptoms may last two weeks or more.
The rash of RMSF is quite characteristic. It usually begins on the fourth day of the illness, and occurs in at least 90% of all patients with RMSF. It starts around the wrists and ankles, as flat pink marks (called macules). The rash spreads up the arms and legs, toward the chest, abdomen, and back. Unlike rashes which accompany various viral infections, the rash of RMSF does spread to the palms of the hands and the soles of the feet. Over a couple of days, the macules turn a reddishpurple color. They are now called petechiae, which are tiny areas of bleeding under the skin (pinpoint hemorrhages). This signifies a new phase of the illness. Over the next several days, the individual petechiae may spread into each other, resulting in larger patches of hemorrhage.
The most severe effects of RMSF occur due to damage to the blood vessels, which become leaky. This accounts for the production of petechiae. As blood and fluid leak out of the injured blood vessels, other tissues and organs may swell and become damaged, and:
- breathing difficulties may arise as the lungs are affected.
- heart rhythms may become abnormal
- kidney failure occurs in very ill patients
- liver function drops
- the patient may experience nausea, vomiting, abdominal pain, and diarrhea
- the brain may swell (encephalitis ) in about 25% of all RMSF patients (brain injury can result in seizures, changes in consciousness, actual coma, loss of coordination, imbalance on walking, muscle spasms, loss of bladder control, and various degrees of paralysis)
- the clotting system becomes impaired, and blood may be evident in the stools or vomit
Diagnosis
Diagnosis of RMSF is almost always made on the basis of the characteristic symptoms, coupled with either a known tick bite (noted by about 60-70% of patients) or exposure to an area known to harbor ticks. Complex tests exist to nail down a diagnosis of RMSF, but these are performed in only a few laboratories. Because the results of these tests take so long to obtain, they are seldom used. This is because delaying treatment is the main cause of death in patients with RMSF.
Treatment
It is essential to begin treatment absolutely as soon as RMSF is seriously suspected. Delaying treatment can result in death.
Antibiotics are used to treat RMSF. The first choice is a form of tetracycline; the second choice (used in young children and pregnant women) is chloramphenicol. If the patient is well enough, treatment by oral intake of medicine is perfectly effective. Sicker patients will need to be given the medication through a needle in the vein (intravenously). Penicillin and sulfa drugs are not suitable for treatment of RMSF, and their use may increase the death rate by delaying the use of truly effective medications.
Very ill patients will need to be hospitalized in an intensive care unit. Depending on the types of complications a particular patient experiences, a variety of treatments may be necessary, including intravenous fluids, blood transfusions, anti-seizure medications, kidney dialysis, and mechanical ventilation (a breathing machine).
Alternative treatment
Although alternative treatments should never be used in place of conventional treatment with antibiotics, they can be useful adjuncts to antibiotic therapy. The use of Lactobacillus acidophilus and L. bifidus supplementaion during and after antibiotic treatment can help rebalance the intestinal flora. Acupuncture, homeopathy, and botanical medicine can all be beneficial supportive therapies during recovery from this disease.
Prognosis
Prior to the regular use of antibiotics to treat RMSF, the death rate was about 25%. Although the death rate from RMSF has improved greatly with an understanding of the importance of early use of antibiotics, there is still a 5% death rate. This rate is believed to be due to delays in the administration of appropriate medications.
Certain risk factors suggest a worse outcome in RMSF. Death rates are higher in males and increase as people age. It is considered a bad prognostic sign to develop symptoms of RMSF within only two to five days of a tick bite.
Prevention
The mainstay of prevention involves avoiding areas known to harbor ticks. However, because many people enjoy recreational activities in just such areas, the following steps can be taken:
- Wear light colored clothing (so that attached ticks are more easily noticed).
- Wear long sleeved shirts and long pants; tuck the pants legs into socks.
- Spray clothing with appropriate tick repellents.
- Examine. Anybody who has been outside for any amount of time in an area known to have a population of ticks should examine his or her body carefully for ticks. Parents should examine their children at the end of the day.
- Remove any ticks using tweezers, so that infection doesn't occur due to handling the tick. Grasp the tick's head with the tweezers, and pull gently but firmly so that the head and body are entirely removed.
- Keep areas around homes clear of brush, which may serve to harbor ticks.
Resources
ORGANIZATIONS
Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. 〈http://www.cdc.gov〉.
KEY TERMS
Encephalitis— Inflammation of the tissues of the brain.
Macule— A flat, discolored area on the skin.
Petechia— A small, round, reddish purple spot on the skin, representing a tiny area of bleeding under the skin.