Fatal Rocky Mountain Spotted Fever

Abstract

Forty-four fatal cases of Rocky Mountain spotted fever (RMSF) occurring in 1974 were compared with 50 nonfatal cases of similar age, sex, date of onset, and place of occurrence. Diagnosis and initiation of treatment in fatal cases were substantially delayed compared with nonfatal cases. Several reasons for this delay were identified: (1) the rash appeared later in the course of illness in the fatal cases, often not until the patient was terminal, (2) a history of tick bite was less often obtained during life or obtained late in the clinical course in fatal cases, and (3) initial nonspecific symptoms or unexpected symptoms led to an initial diagnosis of more common diseases. Only two fatal cases were treated with either tetracycline or chloramphenicol before the sixth day of illness. Presumptive diagnosis of RMSF and initiation of tetracycline therapy before onset of rash may be necessary to reduce mortality.

Rocky Mountain spotted fever in the United States, 1993-1996.

“…Variation of agespecific mortality has been partially attributed to a delay in diagnosis and treatment, as younger patients may develop rash earlier than elderly patients and receive appropriate treatment sooner. 17,18 As in a previous report, whites tended to have a lower case-fatality ratio than that for blacks, 1 perhaps because of earlier detection of a rash in lighter-skinned persons. As in other surveillance reports, fever and headache were the most common symptoms reported, described in 80% to 90% of patients.…”

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

“…Other early symptoms might include nausea or vomiting, abdominal pain, anorexia, and photophobia. A rash typically appears 2-4 days after the onset of fever; however, most patients initially seek health care before appearance of a rash (25,74,98). The classic triad of fever, rash, and reported tick bite is present in only a minority of patients during initial presentation to health care (6,25); therefore, health care providers should not wait for development of this triad before considering a diagnosis of RMSF.…”

“…Delays in diagnosis and initiation of antirickettsial therapy have been associated with seeking health care early in the course of the illness (7,74), late-onset or absence of rash (6,18), and nonspecific or atypical early manifestations, such as gastrointestinal symptoms (18,98) or absence of headache (75). Epidemiologic factors associated with increased risk for death include disease that occurs early or late in the typical tick season (74) and the lack of a report of a tick bite (9,75,98). Although knowledge of the epidemiology might help guide diagnosis, the absence of epidemiologic clues can be misleading.…”

Passive surveillance as an instrument to identify risk factors for fatal Rocky Mountain spotted fever: is there more to learn?

“…In a case-control study based on 1974 surveillance data, researchers compared 44 fatal cases with 50 nonfatal cases of RMSF 31 and found the same suite of significant risk factors (increasing age, initial nonspecific symptoms, no history of tick bite) for fatal outcome. However, although the CFRs were elevated among men and blacks, these results were not statistically significant.…”

“…However, although the CFRs were elevated among men and blacks, these results were not statistically significant. 31 The increased risk for death among adults with RMSF may be attributable to impaired immune function ("immunosenescence") 32 or to delays in diagnosis and treatment initiation among older patients. Because the age-specific incidence of RMSF is highest among children and young adults, one might suspect that delays in diagnosis occur more frequently among older patients than among younger patients.…”