Rocky Mountain Spotted Fever
What is Rocky Mountain spotted fever and how is it contracted?
Rocky Mountain spotted fever (RMSF) is a potentially fatal disease caused by Rickettsia rickettsii. It is transferred to humans by certain types of ticks, mainly the American dog tick, Rocky Mountain wood tick, and brown dog tick. The ticks must be attached to the humans skin for at least six hours for R. rickettsii to be transmitted. The bacterium moves through the body through the lymphatic system, mainly the blood. It uses its outer membrane proteins to attach to the endothelium of blood vessels and are engulfed into blood cells. Then they can replicate by binary fission and are pushed from cell to cell by propelling actin.
Rocky Mountain spotted fever (RMSF) is a potentially fatal disease caused by Rickettsia rickettsii. It is transferred to humans by certain types of ticks, mainly the American dog tick, Rocky Mountain wood tick, and brown dog tick. The ticks must be attached to the humans skin for at least six hours for R. rickettsii to be transmitted. The bacterium moves through the body through the lymphatic system, mainly the blood. It uses its outer membrane proteins to attach to the endothelium of blood vessels and are engulfed into blood cells. Then they can replicate by binary fission and are pushed from cell to cell by propelling actin.
How does Rocky Mountain spotted fever affect different parts of the body?
Most patients will have a high fever.
Most patients will have a high fever.
- Integumentary system: A flat pink rash on the skin covered with red circular bumps will generally show up two days after fever. It breaks out on the wrists and ankles and will spread proximally towards the trunk of the body. Jaundice, yellowing of the skin and whites of eyes, will occur only in very severe cases.
- Cardiovascular system: Myocarditis, an inflammation of the heart muscles, frequently also causes chest pain. Bradycardia, a resting heart rate less than 60 BPM, results in dizziness, weakness, and fatigue. Arrhythmia, an irregular heart beat, and hypotension, low blood pressure, usually occur in less than 16% of patients.
- Gastrointestinal system: Abdominal pain in the upper right quadrant appears in close to all patients. Diarrhea happens in about 20% of cases. Hepatomegaly occurs in 12-15% of patients and is swelling of the liver. Splenomegaly is swelling of the spleen and occurs in 14-16% go patients. Vomiting after any food consumption is also a symptom of nearly every single RMSF case.
- Musculoskeletal system: Extreme myalgia, or muscle pain, occurs in the legs, abdomen and back in about 75% of patients. Arthralgia, or joint pain, occurs in most patients, along with edema, which is swelling of the back of the hands and feet.
- Central nervous system: RMSF does not affect the central nervous system as commonly as it attacks other parts of the body, but when it does, there are many effects. Seizures occur in about 8% of patients, hearing loss, vertigo, restlessness and confusion or the main side effects. Photophobia can also occur, which is sensitive to light; and aphasia, which is difficulty reading, writing, and speaking.
How is Rocky Mountain spotted fever diagnosed and treated?
Because of its many non-disease specific symptoms, RMSF may be incorrectly diagnosed as a wide variety of many other viral and bacterial infections. After this tick-bourne disease is thought to be the problem, there are tests taken to determine the presence of the number of antibodies in the blood and to detect the DNA of R. rickettsii. While these laboratory tests are being done, because the mortality rate nearly doubles within one week without treatment, generalized treatment of symptoms should begin. Rocky Mountain spotted fever is generally treated with antibiotics, and doxycycline is the main choice of treatment for children and adults.
Because of its many non-disease specific symptoms, RMSF may be incorrectly diagnosed as a wide variety of many other viral and bacterial infections. After this tick-bourne disease is thought to be the problem, there are tests taken to determine the presence of the number of antibodies in the blood and to detect the DNA of R. rickettsii. While these laboratory tests are being done, because the mortality rate nearly doubles within one week without treatment, generalized treatment of symptoms should begin. Rocky Mountain spotted fever is generally treated with antibiotics, and doxycycline is the main choice of treatment for children and adults.
Where is Rocky Mountain spotted fever most prevalent?
Although Rocky Mountain spotted fever is the most common fatal tick-transmitted disease in the United States, it is most prevalent in the southeast and the western south central region. Between 1998 and 2005 there were over four times more cases reported, and this may be due to the increase of information and testing. There have been no documentation outside of the Americas- Canada, Mexico, and North, Central, and South America.
Although Rocky Mountain spotted fever is the most common fatal tick-transmitted disease in the United States, it is most prevalent in the southeast and the western south central region. Between 1998 and 2005 there were over four times more cases reported, and this may be due to the increase of information and testing. There have been no documentation outside of the Americas- Canada, Mexico, and North, Central, and South America.
Sources
American Lyme Disease Foundation, Inc.. (n.d.). American Lyme Disease Foundation. Retrieved April 20, 2014, from
http://www.aldf.com/RMSF.shtml#top
Lacz, N. L., Schwartz, R. A., & Kapila, R. R. (2006). Rocky Mountain spotted fever. Journal Of The European Academy Of
Dermatology & Venereology, 20(4), 411-417. doi:10.1111/j.1468-3083.2006.01489.x
O'Brien, M., Cunha, B., & Bronze, M. (n.d.). Rocky Mountain Spotted Fever . Rocky Mountain Spotted Fever . Retrieved April 18,
2014, from http://emedicine.medscape.com/article/228042-overview
American Lyme Disease Foundation, Inc.. (n.d.). American Lyme Disease Foundation. Retrieved April 20, 2014, from
http://www.aldf.com/RMSF.shtml#top
Lacz, N. L., Schwartz, R. A., & Kapila, R. R. (2006). Rocky Mountain spotted fever. Journal Of The European Academy Of
Dermatology & Venereology, 20(4), 411-417. doi:10.1111/j.1468-3083.2006.01489.x
O'Brien, M., Cunha, B., & Bronze, M. (n.d.). Rocky Mountain Spotted Fever . Rocky Mountain Spotted Fever . Retrieved April 18,
2014, from http://emedicine.medscape.com/article/228042-overview