We report a patient who survived acute respiratory failure associated with tick-borne relapsing fever in the third trimester of pregnancy. The fetus was delivered by cesarian section and did not have spirochetemia. The severity of the patient's illness may be related to the immunosuppressive effects of pregnancy.
Relapsing fever is an acute infectious disease caused by spirochetal bacteria belonging to the genus Borrelia. The infection is transmitted by two vectors: the body louse Pediculus humanus, and soft ticks of the genus Ornithodoros. Louse-borne relapsing fever is still a public health problem in developing nations, particularly in Africa and South America. In the United States, relapsing fever is a sporadic illness confined to the Western states and thought to be transmitted exclusively by soft ticks. The extent of infection in this country is unknown. A few outbreaks have been investigated,[1-3] but sporadic cases are generally diagnosed by the discovery of spirochetal bacteria on the Wright-stained blood smear.
The spectrum of illnesses from relapsing fever ranges from a mild self-limited illness to severe cases with death resulting from myocarditis or hepatic failure. Transplacental transmission of Borrelia infection has been reported and may result in abortion.[6,7] While relapsing fever may be associated with bronchitis and pneumonia, it has not been reported as a cause of respiratory failure due to adult respiratory distress syndrome (ARDS). We recently cared for a woman who was pregnant and had relapsing fever that was complicated by ARDS.
A 35-year-old woman in the 30th week of a previously uncomplicated pregnancy was admitted to the hospital September 11, 1988, with fever, thrombocytopenia, and shortness of breath. Two weeks earlier, she had been camping in the Wasatch Mountains of Utah. She had not noted any insect bites during this outing. Two days before hospital admission, she developed mild dyspnea and nausea. Bed rest and fluids were prescribed but her symptoms worsened. Vital signs included blood pressure of 100/80 mm Hg, pulse rate of 120/min, respiratory rate of 36 breaths/min, and temperature of 38.4 [degrees] C. Examination of the chest revealed bibasilar inspiratory and expiratory crackles. Results of cardiac examination were normal. Findings from the abdominal examination were compatible with an intrauterine pregnancy of 30 weeks' gestation. Pelvic examination revealed the cervical mucous plug to be intact with no effacement or dilation of the cervix. Noninvasive fetal monitoring disclosed no sign of fetal distress. She had no rash, ecchymosis, or petechiae, and results of neurologic examination were normal. Initial laboratory studies included WBC count of 8,300/cu mm with 45 percent band forms, 48 percent polymorphonuclear cells, 6 percent lymphocytes, and 1 percent mononuclear cells; hemoglobin level was 10.3 g/dl; and platelet count was 24,000/cu mm. Serum fibrinogen level was 780 mg/dl and fibrin split products were not detected. Specimens of blood and urine were obtained for culture; they were later reported as negative. Results from electrolyte and liver function studies were normal.
Chest roentgenogram at the time of hospital admission (Fig 1) showed diffuse bilateral fluffy infiltrates and no pleural effusion or cardiomegaly. Room air blood gas analysis showed profound hypoxemia with a pH of 7.48, PCO of 25 mm Hg, and PO of 45 mm Hg. The hematology technologist noted fine filamentous bacteria on the Wright-stained blood smear (Fig 2). On review, these were noted to have a corkscrew appearance characteristic of Borrelia and a diagnosis of relapsing fever was made.
Because of the combined risks to the fetus of maternal ARDS and of the Jarisch-Herxheimer reaction that may occur after treatment of relapsing fever, the fetus was delivered by cesarean section. There was no evidence of spirochetemia or sepsis in the infant. Following an uncomplicated cesarean section, the mother was transferred to an intensive care unit where she was treated with tetracycline hydrochloride 500 mg intravenously every 6 h. The patient did not experience any period of hemodynamic instability resembling a Jarish-Herxheimer reaction, but her oxygenation worsened and she was intubated. When the patient's respiratory status was at its worst, she required a positive end-expiratory pressure of 11 and FIO of 0.50 to maintain a PO of at least 50 mm Hg. Thrombocytopenia resolved over 48 h and all blood smears obtained after the first day were negative for any evidence of Borrelia. At no time did the patient produce copious amounts of sputum. She was febrile with a temperature to 38.5 [degrees] C through the fourth hospital day and her WBC count rose to 20,300/cu mm. There was no evidence of wound infection or pelvic thrombophlebitis. A lumbar puncture was performed on the fifth hospital day that yielded clear CSF with 1 WBC per cubic millimeter, protein level of 16 mg/dl, and CSF glucose level 77 mg/dl.
On the sixth hospital day, a computed tomographic (CT) scan of her abdomen showed evidence of a large splenic infarction and infarction of the right kidney. An echocardiogram showed no evidence of valvular abnormalities or pericardial effusion. The patient was continued on a regimen of antibiotic therapy. Her oxygenation improved rapidly and, on the day of discharge from the hospital, her arterial blood gas determination while breathing room air showed a pH of 7.43, PCO of 40 mm Hg, and PO of 57 mm. A subsequent chest roentgenogram was normal (Fig 3).
The list of causes of ARDS includes a wide variety of infections. Cases of ARDS due to leptospirosis and Lyme disease have been reported,[8,9] but other spirochete infections have not been associated with this complication. This patient had unequivocal evidence of Borrelia infection based on her blood smear. While one cannot precisely state the reasons for this patient's pulmonary problems, there was no evidence of suppurative pneumonia or cardiogenic pulmonary edema. She did not have a productive cough, and throughout her ventilator course, she had relatively small amounts of bronchial secretions. She had no evidence of congestive heart failure or myocarditis.
The extent and duration of this patient's pulmonary dysfunction may be related either to particular virulence of the organism, to overwhelming infection, or to the immunologic response to the spirochetal illness. The fact that the organism can be observed readily in thin smears of the blood indicates that a massive number of infecting organisms must be present. The occasional occurrence of Jarisch-Herxheimer reactions suggests the organisms may contain substantial amounts of endotoxin or some other mediator of sepsis. Pregnancy may also be a factor in the severity of our patient's illness. For example, in some infections such as influenza A and falciparum malaria, a higher mortality rate in pregnant women than in age-matched controls[10,11] has been attributed to the immunosuppressive effects of pregnancy. Nonspecific antibody rises may also occur in pregnancy and are additional evidence of altered immunologic responses in pregnant women.
Relapsing fever has been reported in Arizona, California, Idaho, Kansas, Montana, Nevada, New Mexico, Oklahoma, Oregon, Texas Utah, and Washington. Victims of the illness generally have a history of outdoor activity but seldom recall a tick bite. Ornithodoros ticks have a painless bite and feed for short periods of time (5 to 20 min), often while the victim sleeps. The diagnosis should be considered in recent visitors to these areas in the setting of significant outdoor exposure, recurrent fevers, and no diagnosis after evaluation for other causes of fever. Relapsing fever has been successfully treated with [beta]-lactam antibiotics as well as erythromycin, chloramphenicol, and tetracyclines.
Tick-borne relapsing fever is generally mild, but both the disease and its treatment can result in serious morbidity and even death. We now add ARDS as another potentially fatal complication of this disease.
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