Chronic Rocky Mountain Spotted Fever

"Antibacterial treatment should never be delayed while awaiting laboratory confirmation of rickettsial illness, nor should treatment be discontinued solely on the basis of a negative test result with an acute phase specimen." (CDC- MMWR- May 2016- Box 8, Page 30)

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1. RMSF has been reported in every state. (CDC)

2. RMSF is rapidly fatal, growing in incidence, transmitted by several species of ticks and difficult to diagnose. (CDC)

3. There is a "race against time" when treating RMSF. Doxycycline is treatment of choice in all ages. Rapid treatment can prevent death and disability. (CDC) "Patients treated after the fifth day of illness are more likely to die than those treated earlier in the course of illness (9,18,74,75)." (CDC- MMWR- May 2016) Link Here-

4. Multiple diseases, including multiple spotted fever rickettsiosis, can be passed to humans by ticks, many requiring the same treatment as RMSF. (CDC)

Reported incidence rate* of spotted fever rickettsiosis,by county — United States, 2000–2013

* As reported through national surveillance, per 1,000,000 persons per year. Cases are reported by county of residence, which is not always where the infection was acquired.

Includes Rocky Mountain spotted fever (RMSF) and other spotted fever group rickettsioses. In 2010, the name of the reporting category changed from RMSF to spotted fever rickettsiosis.

"The tick vector responsible for A. phagocytophilum transmission in the eastern United States, I. scapularis, also transmits nonrickettsial pathogens in certain geographic areas, including Borrelia burgdorferi, Babesia microti, Borrelia miyamotoi, and deer tick virus (Powassan virus, lineage II). Simultaneous infections with A. phagocytophilum and B. burgdorferi or B. microti have occurred (6971,172). Confirmed Anaplasma coinfection has been reported in <10% of patients with Lyme disease (69,70,172)." "Treatment for patients with anaplasmosis should be extended to 10 days if concurrent Lyme disease is suspected, or alternatively, another antimicrobial with efficacy against Borrelia burgdorferi should be included." (CDC- MMWR- May 23, 2016)

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5. Significant long-term morbidity, permanent damage and chronic symptoms are common in RMSF. Increased health care costs are associated with RMSF. (Duke University Medical Center, CDC, Indiana University School of Medicine)

"The highest incidence occurs in persons aged 60–69 years, and the highest case-fatality rate is among children aged <10 years, although illness occurs in all age groups (4)." (CDC- MMWR- May 2016)

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Clin Infect Dis. 1995 May;20(5):1122-5.

Long-term sequelae of Rocky Mountain spotted fever.

Archibald LK, Sexton DJ.

Twenty-five patients with definite or probable Rocky Mountain spotted fever (RMSF) who were hospitalized for > or = 2 weeks were identified from our database of 105 patients. Follow-up information was collected for 20 patients, per telephone and/or medical records. The remaining five patients were lost to follow-up or died.

Nine patients had > or = 1 long-term sequelae (defined ascomplications related to an original acute infection with Rickettsia rickettsii that persisted for > or = 1 year following hospital discharge). The ages of patients with sequelae ranged from 2 to 74 years (mean and median, 38 years); duration of follow-up ranged from 1 to 18 years (mean, 11 years).

The mean lengths of hospitalization for patients with and without long-term sequelae were 47 days and 20 days, respectively (P < .05).

Long-term neurological sequelae included paraparesis; hearing loss; peripheral neuropathy; bladder and bowel incontinence; cerebellar, vestibular, and motor dysfunction; and language disorders.

Nonneurologicalsequelae consisted of disability from limb amputation and scrotal pain following cutaneous necrosis.

These data suggest that significant long-term morbidity is common in patients with severe illness due to RMSF.


"Long-term neurologic sequelae of RMSF include cognitive impairment; paraparesis; hearing loss; blindness; peripheral neuropathy; bowel and bladder incontinence; cerebellar, vestibular, and motor dysfunction; and speech disorders (7,110,121124).

These complications are observed most frequently in persons recovering from severe, life-threatening disease, often after lengthy hospitalizations, and are most likely the result of R. rickettsii-induced vasculopathy. Cutaneous necrosis and gangrene (Figure 23) might result in amputation of digits or limbs (105)." (CDC- MMWR- May 2016)

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March 31, 2006 / 55(RR04);1-27

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever, Ehrlichioses, and Anaplasmosis --- United States

A Practical Guide for Physicians and Other Health-Care and Public Health Professionals

"RMSF is frequently a severe illness, and patients commonly require hospitalization. Up to 20% of untreated cases and 5% of treated cases have fatal outcome, making RMSF the most commonly fatal rickettsial disease in the United States (5,10).

However, assessment of passive reporting of RMSF-associated death has suggested that only one third of fatal cases of RMSF were reported to CDC during 1983--1998 (77). Therefore, the actual case-fatality rate of RMSF might be closer to 5%--10%.

Host factors associated with severe or fatal RMSF include advanced age, male gender, black race, chronic alcohol abuse, and glucose-6-phosphate-dehydrogenase (G6PD) deficiency (50).

Deficiency of G6PD is a sex-linked genetic condition affecting approximately 12% of the U.S. black male population; deficiency of this enzyme is associated with a high proportion of fulminant cases of RMSF (50,78). Fulminant cases follow a clinical course that is fatal within 5 days of onset.

Long-term health effects persisting for >1 year after acute RMSF infection include partial paralysis of the lower extremities; gangrene requiring amputation of fingers, toes, arms, or legs; hearing loss; blindness; loss of bowel or bladder control; movement disorders; and speech disorders (79).

These complications are observed most frequently in persons recovering from severe, life-threatening disease, often after lengthy hospitalizations. Digital necrosis in a patient occurring late in the course of RMSF has been illustrated (Figure 18)."

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Arch Phys Med Rehabil. 1997 Nov;78(11):1277-80.

Persisting impairment following Rocky Mountain Spotted Fever: a case report.

Bergeron JW, Braddom RL, Kaelin DL.

A patient initially presented in the emergency room with fever, confusion, and a petechial rash. Rocky Mountain Spotted Fever (RMSF) was diagnosed and appropriate treatment was initiated. He subsequently became obtunded and required mechanical ventilation and temporary cardiac pacing.

Four weeks later, he presented to our rehabilitation unit with ataxia, hyperreflexia and upper motor neuron signs, dysesthesias, sensorimotor axonopathy demonstrated by electrodiagnostic studies, and a global decrement in cognitive capability. Although he significantly improved in functional mobility and self-care, he exhibited little improvement in his cognitive impairment at 6-month follow-up.

An understanding of the natural history of, and long-term impairments associated with, RMSF will be helpful to physiatrists in developing rehabilitation care plans and in assisting such patients with community re-entry.


MMWR Recomm Rep. 2016 May 13;65(2):1-44. doi: 10.15585/mmwr.rr6502a1.

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis - United States.

Biggs HM1, Behravesh CB, Bradley KK, Dahlgren FS, Drexler NA, Dumler JS, Folk SM, Kato CY, Lash RR, Levin ML, Massung RF, Nadelman RB, Nicholson WL, Paddock CD, Pritt BS, Traeger MS.

Tickborne rickettsial diseases continue to cause severe illness and death in otherwise healthy adults and children, despite the availability of low-cost, effective antibacterial therapy.

Recognition early in the clinical course is critical because this is the period when antibacterial therapy is most effective.

Early signs and symptoms of these illnesses are nonspecific or mimic other illnesses, which can make diagnosis challenging.

Previously undescribed tickborne rickettsial diseases continue to be recognized, and since 2004, three additional agents have been described as causes of human disease in the United States: Rickettsia parkeri, Ehrlichia muris-like agent, and Rickettsia species 364D.

This report updates the 2006 CDC recommendations on the diagnosis and management of tickborne rickettsial diseases in the United States and includes information on the practical aspects of epidemiology, clinical assessment, treatment, laboratory diagnosis, and prevention of tickborne rickettsial diseases.

The CDC Rickettsial Zoonoses Branch, in consultation with external clinical and academic specialists and public health professionals, developed this report to assist health care providers and public health professionals to 1) recognize key epidemiologic features and clinical manifestations of tickborne rickettsial diseases, 2) recognize that doxycycline is the treatment of choice for suspected tickborne rickettsial diseases in adults and children, 3) understand that early empiric antibacterial therapy can prevent severe disease and death, 4) request the appropriate confirmatory diagnostic tests and understand their usefulness and limitations, and 5) report probable and confirmed cases of tickborne rickettsial diseases to public health authorities.

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6. Testing is unreliable. Patients usually do not have diagnostic serum antibody titers during the first week of illness, and a negative result by IFA assay or ELISA during this period does not exclude the diagnosis of tickborne rickettsial diseases. Source CDC- MMWR- May 13, 2016 Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States. A Practical Guide for Health Care and Public Health Professionals

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7. Deaths have been reported within a week of contracting RMSF, before tests are able to detect antibody titers. (CDC- MMWR- May 2016)

8. Diagnosis is difficult. The classic triad of fever, rash, and reported tick bite is rarely present when patients with RMSF first seek care. Cross-reactive immune responses to rickettsial antigens result in antibodies that are typically group-specific, although perhaps not species-specific, for tickborne rickettsial pathogens (269). For example, antibodies reactive with R. rickettsii detected by a serologic test could result from infection with other SFG rickettsiae (288). Similarly, antibodies reactive with E. chaffeensisor A. phagocytophilum can react with the other species, which can impede epidemiologic distinction between the infections (286,289). Patients with E. ewingii or EML agent infections might develop antibodies that react with E. chaffeensis and, less commonly, A. phagocytophilum antigens (49,145).

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9. Differential diagnosis must be considered. (CDC- MMWR- May 23, 2016)

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Last Update- April 2019

Lucy Barnes