Rocky Mountain Spotted Fever [RMSF]

What is Rocky Mountain Spotted Fever? [RMSF]

 Rocky Mountain Spotted Fever (RMSF) is a serious disease caused by the bacteria Rickettsia rickettsii. It is primarily transmitted through the bite of the American dog tick (Dermacentor variabilis) and the Rocky Mountain wood tick (Dermacentor andersoni), although the brown dog tick (Rhipicephalus sanguineus) has also been implicated in transmission.

 RMSF is a severe and potentially deadly illness. Children are disproportionately affected with more than half of reported cases affecting children under 15 years of age. Adult infections are seen most in those aged 60-69 years.

 RMSF is considered a reportable disease, and physicians are encouraged to report confirmed or suspected cases to their local and state health departments. Cases have been reported in 48 states with the eastern and central states being most common. Five states (North Carolina, Oklahoma, Arkansas, Tennessee, Missouri) account for over 60% of cases. RMSF has also been reported in Canada, Mexico, and Central and South America.

What is Rocky Mountain Spotted Fever? [RMSF]
What is Rocky Mountain Spotted Fever? [RMSF]

What are the symptoms of Rocky Mountain Spotted Fever? [RMSF]

 Symptoms of Rocky Mountain Spotted Fever typically develop within 14 days of the bite of an infected tick. Early symptoms are non-specific and mimic those of many acute illnesses.

Symptoms can include but are not limited to:

  • Fever (up to 104 degrees)

  • Chills

  • Extreme exhaustion

  • Muscle pain

  • Headaches

  • Gastrointestinal (diarrhea, nausea, vomiting, abdominal pain)

  • Rash (see below)

  • Enlargement of the spleen or liver

  • Kidney failure

  • Neurological (muscle weakness, paralysis, encephalitis, coma)

 The rash caused by RMSF is not itchy and often starts on the skin of the wrists and ankles. Eventually, the rash spreads to involve the palms of the hands, soles of the feet, arms, legs, and body. Approximately 10-15% of patients won’t develop a rash at all.

Because it affects the cells lining the blood vessels, R. rickettsia infection can cause life-threatening damage to virtually any tissue or organ. As the blood vessels become more damaged, bleeding in the skin and organs can spontaneously occur, leading to cell death due from a lack of oxygen. Gangrene can develop on the ear tips, fingers, and toes from lack of adequate blood supply.

Individuals with the rare genetic condition, G6PD deficiency, may develop what is called Fulminant Rocky Mountain Spotted Fever. This causes a rapid onset of severe RMSF caused by destruction of red blood cells.

Rocky Mountain spotted fever is multisystemic and potentially severe.

Central nervous system manifestations include:

  • lethargy and confusion (about 25% of all cases),

  • ataxia (18%),

  • coma (9-10%) and

  • seizures (8%).

Other neurologic manifestations include:

  • meningitis,

  • cranial neuropathies,

  • deafness,

  • paralysis,

  • spasticity,

  • vertigo,

  • aphasia and

  • photophobia.

Ophthalmologic complications can also occur. In addition, RMSF affects the respiratory system, the gastrointestinal system and the renal system. Pulmonary involvement includes edema, pneumonia and respiratory distress syndrome. Microcirculatory vasculitis can lead to myocarditis. Close to 10% of patients develop jaundice during the course of their illness; a similar percentage will produce stools positive for occult blood. Hospitalization is frequently required in advanced cases of RMSF. (Ref: http://columbia-lyme.org/patients/tbd_spotted_fever.html)

For a more in-depth discussion on symptoms of RMSF, visit the Rare Disease Database here.

Recovery is possible with early diagnosis and aggressive treatment.

Testing for Rocky Mountain Spotted Fever

Work with your practitioner to order testing for Rocky Mountain Spotted Fever or order a test here.

Summary:

Rocky Mountain Spotted Fever is a serious, potentially fatal tick-borne illness caused by the Rickettsia rickettsii. It develops within 14 days of a bite from an infected tick and progresses rapidly causing a characteristic rash that eventually spreads over the entire body. Without early and aggressive treatment widespread organ damage can occur.

What is Rocky Mountain Spotted Fever FAQs

What is Rocky Mountain Spotted Fever? [RMSF]

Rocky Mountain Spotted Fever (RMSF) is a tick-borne disease caused by the bacterium Rickettsia rickettsii. It is primarily transmitted to humans through the bite of infected ticks, such as the American dog tick, Rocky Mountain wood tick, or brown dog tick.

What are the symptoms of Rocky Mountain Spotted Fever? [RMSF]

The symptoms of RMSF can vary, but commonly include:

  • High fever.

  • Headache.

  • Rash (typically starts on the wrists and ankles and spreads to the trunk).

  • Muscle aches.

  • Nausea and vomiting.

  • Fatigue.

  • Loss of appetite.

  • Abdominal pain. It's important to note that symptoms may not appear immediately after a tick bite and can take up to two weeks to develop.

How is Rocky Mountain Spotted Fever [RMSF] diagnosed?  

Diagnosis of RMSF involves a combination of clinical evaluation, medical history, and laboratory tests. Blood tests can detect antibodies against Rickettsia rickettsii or identify the presence of the bacterium in blood samples. Early diagnosis is crucial for effective treatment.

What is the treatment for Rocky Mountain Spotted Fever? [RMSF]

RMSF is typically treated with the antibiotic doxycycline. Early initiation of treatment is important to prevent complications. Doxycycline is effective in combating the infection, even in children and pregnant women. Other antibiotics, such as chloramphenicol or tetracycline, may be used in certain cases. It is important to talk with your physician about the best treatment for your individual case.

Can Rocky Mountain Spotted Fever [RMSF] be prevented?

Prevention of RMSF involves taking measures to prevent tick bites, including:

  • Avoiding tick-infested areas, such as tall grasses and wooded areas.

  • Wearing long sleeves, long pants, and socks when outdoors.

  • Using insect repellents containing DEET on exposed skin and clothing.

  • Conducting regular tick checks on yourself, family members, and pets after being outdoors.

Are there any complications associated with Rocky Mountain Spotted Fever? [RMSF]

RMSF can lead to severe complications if left untreated or if treatment is delayed. These complications may include organ damage, neurological problems, respiratory distress, blood clotting disorders, and in rare cases, even death. Prompt diagnosis and treatment are crucial to prevent complications.

Is Rocky Mountain Spotted Fever limited to the Rocky Mountain [RMSF] region?

Despite its name, RMSF is not limited to the Rocky Mountain region and can occur in various parts of the United States and other countries. It is important to be aware of the risk of RMSF in your specific geographical area and take preventive measures accordingly.

Can pets transmit Rocky Mountain Spotted Fever [RMSF] to humans?

Pets, such as dogs, can contract RMSF from tick bites, but they do not directly transmit the infection to humans. However, infected ticks can bite both humans and animals, so protecting pets from ticks can indirectly reduce the risk of tick bites for humans.

It is essential to consult with a healthcare professional or local health authorities for accurate diagnosis, appropriate treatment, and specific prevention strategies based on your geographical location and individual circumstances.