The Medico-Legal Advisor ®
Rocky Mountain Spotted FeverRocky mountain spotted fever (RMSF) is not a statistically important disease in terms of numbers of cases reported. Nor is it appropriately named. Its importance relates to its seasonal nature (all cases reported in the summer months), the specificity of treatment required to cure it, the fact that the diagnosis depends more on intuition than on specific diagnostic tests and the high mortality of undiagnosed and untreated cases. HISTORY: RMSF got its name in 1906 when a man named Ricketts in Montana's Bitterroot valley established that the bite of the wood tick was responsible for transmitting the disease. Since 1906 the distribution of the disease has changed dramatically. Now the Rocky Mountain states have the fewest cases and the mid-Atlantic states have the highest attack rate. North Carolina reports the highest number of cases yearly followed by South Carolina, Georgia, Oklahoma and Tennessee. ETIOLOGY: RSMF is caused by micro-organisms called rickettsia which are fragile except when living in a host organism. They live in wild rodents and dogs and are transmitted to man by ticks. The tick feeds on the host and becomes infested with the organism, then drops off and passes the disease to the next animal or man on which it feeds. The wood tick, dog tick and lone star tick are the most common ones implicated. It appears that a large innoculum of the organism is necessary to produce serious disease and that lesser amounts of the organism produce mild or even sub-clinical disease. It is said that a tick must be attached for three to four hours to produce a full-blown case of the disease. The tick either transmits the organism as it feeds or it defecates high quantities of the organism onto the skin which is subsequently rubbed in. As high as 20% of children tested with various serological tests seem to have been exposed, and in Suffolk county, New York where the disease is endemic, 11 % of ticks were infested with rickettsia when collected and tested. Once inside of the human body, the rickettsiae seek out the cells lining small blood vessels where they multiply and destroy those cells. A vasculitis results with thrombosis of some small vessels and leakage of fluid from many. Virtually every organ of the human body is vulnerable to attack which means that the symptoms can vary greatly from individual to individual. CLINICAL MANIFESTATIONS: Two to twelve days after tick implantation, the infected human will experience chills, fever, severe generalized headache, muscle aching and vomiting. Abdominal pain may occur as the predominant early symptom. In other cases the disease has presented as an upper respiratory tract infection with other symptoms coming on later. Lethargy and coma come on fairly quickly in some cases. The characteristic rose-colored, blanching rash usually occurs three to five days after the onset of symptoms, appearing on the hands and feet first and spreading centrally. In 4 to 15% of cases the rash never develops. If the disease remains untreated, clotting abnormalities and disseminated intravascular coagulation occur, leading to intractable shock and death. DIAGNOSIS: A history of tick exposure and the presence of the rash tip practitioners off in the ordinary case but these two bits of information only occur in about two thirds of the cases in time to do the patient much good. Laboratory tests are not very helpful since the serological tests indicative of the disease are not positive for up to 14 days. Immunoflourescence of skin and tissue biopsies is a good test but it is not generally available. Since most of the fatalities involve a delay in treatment in patients who have promptly sought medical attention, and since the incidence of the disease is low enough that no practitioner or medical center will gain a lot of experience with it, a high degree of suspicion on the part of primary care physicians is necessary to prevent needless fatalities, TREATMENT: Early administration of tetracyclene (or the more hazardous antibiotic, chloramphenicol) will result in prompt remission. If the patient is already severely ill, supportive therapy with IV fluids and treatment of coagulation abnormalities is essential. Some fatal cases of RMSF would undoubtedly have been saved if reasonable judgment had been used. Often fatalities have involved obviously dehydrated children (or adults over the age of forty) with high fevers and lethargy in whom supportive therapy would have saved the day had it not been denied them. Prevention involves avoiding tick infested areas, frequent inspection of one's body when in the tick's habitat, and appropriate handling of the attached tick. There is no vaccine available. Nor have other methods of prevention such as irradication of ticks or of small animals which serve as hosts been effective except in isolated instances. When a tick is found attached to the skin, DO NOT SQUEEZE THE LITTLE BOOGER. Application of gasoline, lighter fluid, kerosene or alcohol or touching him with a hot object such as a match or cigarette will make him back out. Vaseline or mineral oil are also reportedly effective in making the tick loosen his hold. Squeezing the tick will cause him to defecate and leave whatever organisms he is carrying with you. Removing the tick with a forceps (tweezers) is safe but may leave the mouth parts which will then require removal. They act as a foreign body, causing inflammation and infection. In summary, RMSF is a disease effecting only a small number of Americans, mostly in the mid-atlantic states. It is only transmitted if rickettsia-infested ticks are left attached for long periods of time. Proper and prompt removal of attached ticks will prevent the disease. The disease is difficult to diagnose since virtually no help can be obtained from diagnostic tests; but once diagnosed it is easily treated with tetracyclene and supportive measures. Only in instances where treatment is delayed will the disease proceed to permanent sequelae or death.
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