title: Host- and microbe-related risk factors for and pathophysiology of fatal Rickettsia conorii infection in Portuguese patients.
abstract: BACKGROUND
  The pathophysiologic mechanisms that determine the severity of Mediterranean spotted fever (MSF) and the host-related and microbe-related risk factors for a fatal outcome are incompletely understood.
  
  
  METHODS
  This prospective study used univariate and multivariate analyses to determine the risk factors for a fatal outcome for 140 patients with Rickettsia conorii infection admitted to 13 Portuguese hospitals during 1994-2006 with documented identification of the rickettsial strain causing their infection.
  
  
  RESULTS
  A total of 71 patients (51%) were infected with the Malish strain of Rickettsia conorii, and 69 (49%) were infected with the Israeli spotted fever (ISF) strain. Patients were admitted to the intensive care unit (40 [29%]), hospitalized as routine inpatients (95[67%]), or managed as outpatients (5[4%]). Death occurred in 29 adults (21%). A fatal outcome was significantly more likely for patients infected with the ISF strain, and alcoholism was a risk factor. The pathophysiology of a fatal outcome involved significantly greater incidence of petechial rash, gastrointestinal symptoms, obtundation and/or confusion, dehydration, tachypnea, hepatomegaly, leukocytosis, coagulopathy, azotemia, hyperbilirubinemia, and elevated levels of hepatic enzymes and creatine kinase. Some, but not all, of these findings were observed more often in ISF strain-infected patients.
  
  
  CONCLUSIONS
  Although fatalities and similar clinical manifestations occurred among both groups of patients, the ISF strain was more virulent than the Malish strain. Multivariate analysis revealed that acute renal failure and hyperbilirubinemia were most strongly associated with a fatal outcome.
authors.affiliation: Centro de Estudos de Vectores e Doenças Infecciosas, Instituto Nacional de Saúde Dr Ricardo Jorge, Faculdade de Ciências Médicas de Lisboa, Lisboa, Portugal.
authors.forename: Rita de
authors.initials: Rd
authors.lastname: Sousa
authors.forename: Ana
authors.initials: A
authors.lastname: França
authors.forename: Sónia
authors.initials: S
authors.lastname: Dória Nòbrega
authors.forename: Adelaide
authors.initials: A
authors.lastname: Belo
authors.forename: Mario
authors.initials: M
authors.lastname: Amaro
authors.forename: Tiago
authors.initials: T
authors.lastname: Abreu
authors.forename: José
authors.initials: J
authors.lastname: Poças
authors.forename: Paula
authors.initials: P
authors.lastname: Proença
authors.forename: José
authors.initials: J
authors.lastname: Vaz
authors.forename: Jorge
authors.initials: J
authors.lastname: Torgal
authors.forename: Fátima
authors.initials: F
authors.lastname: Bacellar
authors.forename: Nahed
authors.initials: N
authors.lastname: Ismail
authors.forename: David H
authors.initials: DH
authors.lastname: Walker
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D001907:Boutonneuse Fever / Q000453:epidemiology / Q000401:mortality / Q000503:physiopathology*; D015897:Comorbidity; D006801:Humans; D015999:Multivariate Analysis; D011174:Portugal / Q000453:epidemiology; D011446:Prospective Studies; D012282:Rickettsia Infections / Q000453:epidemiology* / Q000382:microbiology; D020114:Rickettsia conorii / Q000302:isolation & purification / Q000472:pathogenicity*; D012307:Risk Factors