Tick-borne diseases in Texas: a 10-year retrospective examination of cases

The occurrence of Rocky Mountain spotted fever, human monocytotropic ehrlichiosis, tularemia, tick-borne relapsing fever, and a southern erythema migrans-like illness (Lyme/Lyme-like disease) is determined by the geographic distribution and seasonal activity of the particular vector tick(s). The flulike signs and symptoms early in the course of spotted fever rickettsiosis, ehrlichiosis, tularemia, and relapsing fever are nonspecific and do not readily suggest a particular diagnosis. Laboratory diagnosis, particularly during the acute stage of illness, often is elusive. Empiric treatment with doxycycline can be lifesaving for Rocky Mountain spotted fever and ehrlichiosis. This article provides insight into the significance of each of these tick-transmitted diseases in Texas.     

Ticks and tick-borne diseases in Oklahoma

Tick-borne diseases are common in Oklahoma, especially the eastern part of the state where tick prevalence is highest. Three species of hard ticks are present in Oklahoma that are known vectors of human disease--the American dog tick (Rocky Mountain spotted fever; RMSF), the lone star tick (ehrlichiosis) and the black-legged tick (Lyme disease). Oklahoma consistently ranks among the top states in numbers of reported RMSF cases, and Ehrlichiosis may be as prevalent as RMSF. Although Lyme disease is frequently reported in Oklahoma, over-diagnosing of this disease due to false-positive test results is common; positive or equivocal screening tests should be confirmed by Western immunoblot. At present, it is unclear whether the disease seen here is Lyme disease or another Lyme-like disease. If true Lyme disease is present in the state, it is probably rare. Physicians should be aware of the most recent recommendations for diagnosis, therapy and prevention of tick-borne diseases.     

The great imitator: Rocky Mountain spotted fever occurring after hospitalization for unrelated illnesses

We describe two patients who had Rocky Mountain spotted fever after they were admitted to the hospital for emergency and elective surgical procedures. We initially thought one patient had a hospital-acquired infection; the correct diagnosis was deduced from epidemiologic clues elicited by consultants. These two cases were also unusual in that one patient had a recurrent rash after an abbreviated course of low-dose doxycycline therapy and the other patient had transient and self-limiting postinfectious polyneuropathy. These cases illustrate that community-acquired infection with Rickettsia rickettsii can occur simultaneously with other disease processes and sometimes mimic a nosocomial infection.     

Meningoencephalitis due to Rickettsia conorii. Etiopathological, clinical and diagnostic aspects

Boutonneuse fever (BF) is usually considered to be a benign rickettsiosis. However, severe presentations, resembling Rocky Mountain spotted fever, have been reported. There are few neurological complications, except in serious forms of the disease. We present a case of meningoencephalitis in a male adult suffering from BF, and we review the clinical, etiopathogenic and diagnostic aspects among the cases previously reported. We conclude that BF encephalitis would have the following characteristics: a) they mostly affect elderly males; b) they cause altered consciousness level, headaches and low rate of meningeal signs; c) absence of "tache noir"; d) cerebrospinal fluid with slight pleocytosis and/or increased level of proteins, and normal glucose values; e) computerized tomography without significative changes, and f) high rate of morbidity and mortality. We emphasize that we should consider BF in the differential diagnosis of our environmental encephalitis.     

Inflammatory diseases of the central nervous system in dogs

Inflammatory diseases of the central nervous system (CNS) are important causes of seizures in dogs. Specific diseases include canine distemper, rabies, cryptococcosis, coccidioidomycosis, toxoplasmosis, neosporosis, Rocky Mountain spotted fever, ehrlichiosis, granulomatous meningoencephalomyelitis, and pug dog encephalitis. Inflammatory disorders should be considered when a dog with seizures has persistent neurological deficits, suffers an onset of seizures at less than 1 or greater than 5 years of age, or exhibits signs of systemic illness. A thorough history, examination, and analysis of cerebrospinal fluid are important in the diagnosis of inflammatory diseases. However, even with extensive diagnostic testing, a specific etiology is identified in less than two thirds of dogs with inflammatory diseases of the CNS.     

Laboratory evaluation in the diagnosis of Lyme disease

PURPOSE: To provide a qualitative evaluation of the predictive value of the laboratory diagnosis of Lyme disease and to use the resultant data to formulate guidelines for clinical diagnosis. DATA SOURCES: A MEDLINE search of English-language articles or articles with English-language abstracts published from 1982 to 1996. DATA EXTRACTION: Sensitivity, specificity, and likelihood ratios were calculated, and a random-effects model was used to combine the proportions from the eligible studies. Prespecified criteria were used to determine which studies were eligible for analysis. DATA SYNTHESIS: Laboratory testing in general is not clinically useful if the pretest probability of Lyme disease is less than 0.20 or greater than 0.80. When the pretest probability is 0.20 to 0.80, sequential testing with enzyme-linked immunosorbent assay and Western blot is the most accurate method for ruling in or ruling out the possibility of Lyme disease. CONCLUSIONS: Laboratory testing is recommended only in patients whose pretest probability of Lyme disease is 0.20 to 0.80. If the pretest probability is less than 0.20, testing will result in more false-positive results than true-positive results; a negative test result in this situation effectively rules out the disease.     

Disposition and metabolism of the new hypocholesterolemic compound S-8921 in rats and dogs

Antimicrobial agents are appropriate treatment for acute, severe, persistent, or progressive infectious diseases. The efficacy of treatment depends on the accuracy of the diagnosis of infection and the appropriateness of the antimicrobial agent for the causative microorganism. In this symposium, the antimicrobial agents reviewed correspond with the bacterial, fungal, viral, mycobacterial, parasitic, chlamydial, and other microorganisms that cause disease in humans. Usually, the etiologic possibilities can be limited on the basis of the history and physical examination, laboratory tests, or results of treatment trials. Many of the same findings, however, can result from noninfectious, other inflammatory, or unknown mechanisms. Manifestations such as fever and organ dysfunction are nonspecific and often not caused by an infectious process. Even when infection is clinically apparent, the causative microorganism may not be identified, and empiric treatment with broad-spectrum agents is appropriate in many cases of serious disease.     

Inappropriate antidiuretic hormone secretion. Occurrence in a patient with Rocky Mountain spotted fever

A 51-year-old man with serologically confirmed Rocky Mountain spotted fever was believed to have inappropriate antidiuretic hormone (ADH) secretion. He was observed for four days in the hospital until the correct diagnosis was made. During this period, he progressively became more hyponatremic, despite a low BUN level and the administration of large amounts of sodium and water. At the time, his serum sodium concentration was 117 mEq/liter, and his urine was hypertonic to that of serum. Thereafter, his serum sodium level rose with fluid restriction. Rickettsia-induced CNS damage may have lead to the inappropriate ADH release that was observed in this patient.     

Lethal effect of Rickettsia rickettsii on its tick vector (Dermacentor andersoni)

Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, was lethal for the majority of experimentally and transovarially infected Rocky Mountain wood ticks (Dermacentor andersoni). Overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88. 3% of adult female ticks infected as nymphs died prior to feeding. In contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. Infected female ticks incubated at 4 degreesC had a lower mortality (80.9%) than did those held at 21 degreesC (96.8%). Rickettsiae were vertically transmitted to 39.0% of offspring, and significantly fewer larvae developed from infected ticks. The lethal effect of R. rickettsii may explain the low prevalence of infected ticks in nature and affect its enzootic maintenance.     

Simulated bleeding--a forgotten disease in a land of plenty

Although Rocky Mountain spotted fever was documented in northern Mexico during the 1940s, spotted fever group (SFG) rickettsioses have subsequently received little attention in Mexico. In this study, sera collected in 1993 from 50 patients from the Mexican states of Yucatan and Jalisco, who were suspected clinically to have dengue fever but had no antibodies to dengue virus, were examined by indirect immunofluorescence for IgM antibodies reactive with Rickettsia rickettsii, R. akari, and R. typhi. Twenty (40%) of the patients' sera contained IgM antibodies to SFG rickettsiae at a titer of 128 or greater. Among five sera reactive only against R. akari, four were from patients in Jalisco where a cluster of cases occurred in June and July. Among five sera reactive only with R. rickettsii, all were from Yucatan patients. Sera of 10 patients contained antibodies reactive with antigens shared by R. rickettsii and R. akari. The clinical signs and symptoms (fever, 100%; myalgia, 95%; headache, 85%; rash, 85%) were similar to those of dengue fever patients identified in this study. However, the incidence of rash was substantially higher than the nondengue, nonrickettsiosis patients. One or more SFG rickettsioses appear to be present in areas of Mexico not previously recognized to harbor these organisms. The etiologic agent or agents are as yet unknown.     

European Union Concerted Action on Risk Assessment in Lyme Borreliosis: clinical case definitions for Lyme borreliosis

The EU Concerted Action on Risk Assessment in Lyme Borreliosis (EUCALB) has consulted other clinicians and scientists in Europe to produce case definitions of the principal manifestations of European Lyme borreliosis. These case definitions will not only be helpful in supporting its own research interests, but are also intended to assist other clinicians in appropriate management and to support further studies aimed at determining the full clinical spectrum of the disease. The case definitions were achieved after a series of meetings organised by EUCALB with other expert clinicians and scientists from twelve European countries. The definitions and the diagnostic criteria presented thus represent the consensus reached at these meetings. The proposed case definitions consider skin, nervous system, cardiac and musculoskeletal presentations and the role of laboratory investigation in supporting diagnosis.     

Intellectual sequelae of Rocky Mountain spotted fever.

Administered the WISC, Marianne Fostig Developmental Test of Visual Perception, and Bender-Gestalt Test to 12 6-15 yr. old former Rocky Mountain spotted fever (RMSF) patients and 12 matched controls. Significant differences were obtained on 7 of 13 WISC scales and on 2 of 5 Fostig subsets. However, no differences were found on the Bender-Gestalt. It is concluded that RMSF exerts a mild but consistent effect on intellectual functioning. This in turn suggests a higher probability of learning disability and corresponding difficulty with school performance in former RMSF patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erythema migrans-like rash illness at a camp in North Carolina: a new tick-borne disease?

BACKGROUND: Borrelia burgdorferi, the causative agent of Lyme disease, has never been isolated from a patient thought to have acquired Lyme disease in any southeastern state. OBJECTIVE: To investigate 14 cases of an erythema migrans (EM)-like rash illness that occurred during 2 summers at an outdoor camp in central North Carolina in an effort to determine the etiologic, epidemiological, and clinical aspects of this illness. METHODS: Using active surveillance, we identified cases of clinically diagnosed EM in residents and staff of the camp. We collected clinical and demographic information; history of exposure to ticks; acute and convalescent serum antibodies to B. burgdorferi, Rickettsia rickettsii, and Ehrlichia chaffeensis; and cultures for spirochetes from biopsy specimens of skin lesions. Serum samples from a group of residents and staff who did not develop rashes were tested for the same antibodies. We speciated ticks removed from people and collected from vegetation. RESULTS: We identified 14 cases of EM-like rash illness during the 2 summers. Of the 14 case-patients, 10 had associated mild systemic symptoms and 1 had documented fever. All 14 case-patients had removed attached ticks, and 8 remembered having removed a tick from the site where the rash developed a median of 12 days earlier (range, 2-21 days). One tick removed from the site where a rash later developed was identified as Amblyomma americanum, the Lone Star tick; 97% of ticks collected from vegetation and 95% of ticks removed from people were A. americanum. No spirochetes were isolated from skin biopsy specimens. Paired serum samples from 13 case-patients did not show diagnostic antibody responses to B. burgdorferi or other tick-borne pathogens. CONCLUSIONS: This investigation suggests the existence of a new tick-associated rash illness. We suspect that the disease agent is carried by A. americanum ticks. In the southern United States, EM-like rash illness should no longer be considered definitive evidence of early Lyme disease.     

Gallium-67-citrate scanning of renal parenchymal malacoplakia

The purpose of this article is to review the potential role of nuclear medicine scanning, especially with 67Ga, in the presumptive diagnosis and clinical management of patients with renal parenchymal malacoplakia (RPMP), a rare disease associated with coliform bacterial infection of the kidney and characterized by chronic unresolving inflammatory infiltrates containing von Hansemann macrophages in the renal parenchyma. METHODS: Published cases of RPMP were collected from the archival literature by searching the MEDLINE database and by reviewing bibliographic references contained in articles on malacoplakia. Data on the clinical features and radiographic evaluation of patients with RPMP were extracted from the clinical case reports. RESULTS: Forty-three cases of RPMP published over the past 20 yr were identified. Ten of the 43 patients (23%) had 67Ga scanning as a component of their diagnostic evaluation. In all 10 patients, renal uptake of 67Ga was classified as intense. Two of those 10 patients had serial 67Ga scanning performed to assess response to antibiotic treatment; both patients exhibited decreased uptake or complete resolution of abnormal renal uptake over time, a finding also exhibited by our patient. CONCLUSION: Intense renal uptake of 67Ga, typically in the clinical setting of fever, progressive renal failure and nephromegaly, strongly supports a diagnosis of RPMP. In those patients receiving prolonged antimicrobial therapy for RPMP, resolution of abnormal 67Ga uptake over time may provide an objective endpoint for treatment.     

A new Borrelia species isolated from patients with relapsing fever in Spain

BACKGROUND: Lyme disease and tick-borne relapsing fever are worldwide systemic borrelioses caused by several Borrelia species transmitted by hard ticks (family Ixodidae) and soft ticks (family Argasidae), respectively. A previous seroepidemiological study of Lyme borreliosis showed several serologically reactive patients with clinically atypical presentations, and this discovery led to the hypothesis that some of the cases of Lyme borreliosis had been caused by another borrelia organism. METHODS: Blood from patients in southern Spain who had suspected Lyme disease or relapsing-fever borreliosis was cultured before treatment began. Isolates of Borrelia spp were inoculated into several strains of mice of different ages. The 16S rRNA and flagellin in genes of Borrelia spp were sequenced by PCR and assessed by phylogenetic analyses. FINDINGS: We isolated a species of Borrelia from three patients with relapsing fever and from Ornithodorus spp ticks in southern Spain. This organism (refractory to in-vitro cultivation) caused a relapsing spirochaetaemia with multiple organ involvement in laboratory mice that recreated the human disease. Phylogenetic analysis showed that this organism is a previously unrecognised species. INTERPRETATION: We have discovered a new borrelia pathogen that is closely related to the other tick-borne agents of relapsing fever in Europe and Africa, and which causes a relapsing systemic disease with serological similarities to Lyme borreliosis.     

Fine particulate organic material in the Los Angeles Basin-I: assessment of the high-volume Brigham Young University organic sampling system, BIG BOSS

BACKGROUND AND OBJECTIVE: Acute generalized, widespread bleeding is often related to disseminated intravascular coagulation (DIC), a pathologic process which complicates the clinical course of many diseases and is characterized by huge amounts of thrombin and plasmin within the circulation. The final result is the consumption of platelets, coagulation factors and inhibitors, as well as secondary hyperfibrinolysis, all leading to diffuse hemorrhage and microthromboses. This review article examines the present attitudes to the diagnosis and treatment of overt DIC in clinical practice, emphasizing the importance of an accurate differential diagnosis from some other processes characterized by acute generalized, widespread bleeding. INFORMATION SOURCES: The authors have been working in this field, both at experimental and clinical levels, contributing original papers for many years. In addition, material examined in this review includes articles published in journals covered by MedLine, recent reviews in journals with high impact factor and in relevant books on hemostasis and thrombosis. STATE OF ART AND PERSPECTIVES: DIC is an intermediary mechanism of disease which complicates the clinical course of many well-known disorders. Although the systemic hemorrhagic syndrome is the predominant clinical manifestation, massive intravascular thrombosis frequently occurs contributing to ischemia and associated organ damage, making the mortality rate of this condition high. Current concepts on the pathophysiology, laboratory diagnosis and management of DIC are presented. Complex pathophysiological interrelations make the diagnosis of the etiology of the DIC difficult in clinical practice, although simple tests are useful for identification of patients with the process. Laboratory diagnosis of DIC is mainly based on screening assays, which allow a rapid diagnosis, whereas some other highly sensitive but more complex assays are not always available to routine clinical laboratories. The management of DIC is based on the treatment of the underlying disease, supportive and replacement therapies and the control of the coagulation mechanisms. Although some advances have been achieved, management decisions are still controversial, so that therapy should be highly individualized depending on the nature of the DIC and severity of clinical symptoms. Many syndromes sharing common findings with DIC, such as primary hyperfibrinolysis or thrombotic thrombocytopenic purpura, should be excluded. Finally, new therapeutic approaches to the management of this potentially catastrophic syndrome are required.     

Leptomeningeal metastasis: pathophysiology, treatment, and nursing management

PURPOSE/OBJECTIVES: To review the pathophysiology, diagnosis, and clinical treatment of leptomeningeal metastasis. DATA SOURCES: Published articles, abstracts, and book chapters. DATA SYNTHESIS: Leptomeningeal metastasis is an increasingly seen complication of cancer. Treatment is intensive and may increase survival from four to five weeks without treatment to an average of six months. Clinical management and treatment of these patients is complex and best accomplished by a multi-disciplinary healthcare team. CONCLUSIONS: Information regarding the anatomy, pathophysiology, treatment, and treatment complications can facilitate the care of patients with leptomeningeal metastasis. IMPLICATIONS FOR NURSING PRACTICE: Nursing interventions should focus on patient and family education about the disease process, side-effects of treatment, and early identification of disease progression.     

Infection and atherosclerosis--focus on cytomegalovirus and Chlamydia pneumoniae

BACKGROUND AND OBJECTIVE: Numerous studies have reported an association of coronary atherosclerosis and restenosis with certain bacterial and viral infections. This article reviews the pathophysiology of atherosclerosis, the role of infectious agents (i.e, cytomegalovirus and Chlamydia pneumoniae) in atherogenesis, and studies supporting the potential beneficial effects of antibiotics or antiviral agents in the management of atherosclerotic disease. DATA SOURCES: English-language clinical studies, abstracts, and review articles pertaining to infectious agents and coronary atherosclerosis. STUDY SELECTION AND DATA EXTRACTION: Relevant seroepidemiologic and pathologic studies and animal models evaluating the role of cytomegalovirus or C. pneumoniae in coronary atherosclerosis. DATA SYNTHESIS: Studies evaluating the possible role of cytomegalovirus and C. pneumoniae in the pathogenesis of atherosclerosis, as well as studies examining the use of antimicrobial and antiviral agents for reduction of cardiovascular events, are reviewed and critiqued. CONCLUSIONS: Current data do not allow us to determine whether infection is a cause or a cofactor of atherosclerosis. These uncertainties can be resolved by larger scale seroepidemiologic, pathologic, and interventional studies. Such efforts will contribute to identifying populations that are appropriate for particular surveillance or specific interventions, such as antibiotics or antiviral therapy.     

Endophthalmitis

Endophthalmitis is an inflammatory reaction of intraocular fluids or tissues. Infectious endophthalmitis is one of the most serious complications of ophthalmic surgery. Occasionally, infectious endophthalmitis is the presenting feature of an underlying systemic infection. Successful management of infectious endophthalmitis depends on timely diagnosis and institution of appropriate therapy. Recognition of the different clinical settings in which endophthalmitis occurs and awareness of the highly variable presentation it may have facilitate timely diagnosis. Biopsy of intraocular fluid/tissue is the only method that permits reliable diagnosis and treatment. The different presenting clinical settings, a rational approach to diagnosis (i.e., when, what, and how to biopsy), and the treatment of infectious endophthalmitis are reviewed.