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Corresponding author: Professor Philippe Parola, Institut Hospitalo-Universitaire Méditerranée Infection, 19-21 Boulevard Jean Moulin, Marseille 13385 Cedex 05, France.
Mediterranean spotted fever is a rickettsial infection caused by Rickettsia conorii.
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Infection occurs after the bite of an infected Rhipicephalus sanguineus tick.
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Focal neurological manifestations are rare and poorly described in the literature.
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This case highlights the management of peripheral facial palsy associated with infection.
Abstract
Mediterranean spotted fever (MSF) caused by the bacterium Rickettsia conorii is one of the oldest known tick-borne diseases. It is transmitted by the brown dog tick Rhipicephalus sanguineus and occurs mainly in the Mediterranean area. MSF usually presents with a skin rash, high fever, and characteristic eschar at the site of the tick bite. The course of this disease may be benign or life-threatening. Focal neurological manifestations are unusual. We report the case of a patient who presented with an isolated peripheral facial nerve palsy complicating R conorii conorii infection.
Mediterranean spotted fever (MSF) is a zoonotic disease caused by Rickettsia conorii conorii, a tick-borne pathogen belonging to the spotted fever group (SFG) rickettsiae, and is transmitted by the brown dog tick Rhipicephalus sanguineus. MSF is endemic in North Africa including Algeria and Southern European countries bordering the Mediterranean Sea (
). MSF may present as a benign or life-threatening condition. It is characterized by fever, rash, and a black eschar (“tache noire”) at the site of the tick bite, a hallmark of many SFG rickettsioses (
). Focal neurological manifestations are unusual. We report the case of a young female patient who presented with peripheral facial nerve palsy complicating R conorii infection.
2. Case Report
A 12-year-old girl with no significant medical history presented to the infectious diseases outpatient unit with a 6-day history of febrile maculopapular rash associated with arthralgia. The patient's history was notable for contacts with dogs. Physical examination revealed fever (39°C), tachycardia (95 bpm), and tachypnea (26/min). Cutaneous examination revealed a generalized maculopapular rash, which was more prominent on the lower limbs. The rash consisted of erythematous indurated lesions, a few millimeters in diameter (Figure 1). Routine laboratory findings showed leukocytosis (13,000 leukocytes/mL) and C–reactive protein (CRP) elevation at 76 mg/L. All other parameters were within the reference range. Chest radiography did not show abnormalities. Serum samples and a dry swab obtained from the eschar were also sent to the Reference Center for Rickettsial Diseases in Marseille, France, for specific diagnosis.
Figure 1(A) Picture of the patient's face showing peripheral facial palsy with loss of the nasolabial fold. (B) Picture showing a dark-brown inoculation eschar on the site of the tick bite. (C) Picture of the anterior view of the patient's legs, showing a generalized erythematous maculopapular rash.
The patient was started on oral doxycycline 200 mg/day for 7 days. On the second day after admission, the patient presented with sudden left peripheral facial palsy (Figure 1). Physical examination revealed asymmetry at rest and acute-onset drooping of the left eye. No ocular pain or redness was noted. Otoscopic examination showed a normal tympanum on both sides. Head and neck examination did not indicate the presence of any parotid lesion. Neurological examination did not reveal any other abnormality. The contrast-enhanced computed tomography scan of the brain including orbital cuts and the cerebrospinal fluid examination did not reveal any abnormalities. The patient received oral prednisone at a dosage of 2 mg/kg per day for 7 days, which was gradually tapered within 7 days. The outcome was favorable, with apyrexia noted after 3 days of treatment. One month later, on a follow-up evaluation, the girl had regained normal left facial nerve function.
The serum samples and dry swab were secondarily studied in Marseille, France. A Rickettsia serological assay was performed. Indirect immunofluorescence (IFI) testing was positive for R conorii, with an IgG titer of 1:2048 (reference range < 1:128) and IgM titer of 1:256 (reference range < 1:64) (
). DNA extraction was obtained from the dry swab sample, and the eluate was screened in real-time quantitative polymerase chain reaction (qPCR) with genus-specific primers and probes targeting a fragment of the gltA gene of all SFG Rickettsia species (
Urban Family Cluster of Spotted Fever Rickettsiosis Linked to Rhipicephalus Sanguineus Infected with Rickettsia Conorii Subsp. Caspia and Rickettsia Massiliae.
) using a CFX Connect™ Real-Time PCR Detection System (Bio-Rad) and the Eurogentec Takyon qPCR kit (Eurogentec). Because the sample was positive, it was tested with species-specific R massiliae and R conorii qPCR, targeting fragments of a hypothetical protein and the putative acetyltransferase genes, respectively (
Urban Family Cluster of Spotted Fever Rickettsiosis Linked to Rhipicephalus Sanguineus Infected with Rickettsia Conorii Subsp. Caspia and Rickettsia Massiliae.
). DNA extract from cultures of R massiliae and R conorii were used as qPCR positive controls. The specific assay for R conorii was positive, confirming the diagnosis of MSF.
3. Discussion
We reported the case of a young female patient who presented with a typical MSF associated with peripheral facial nerve palsy. Although rare, some neurological complications have been described in MSF: meningoencephalitis, myelitis, Guillain-Barré syndrome, and facial nerve paralysis (
MSF is a systemic disease, with symptoms caused by vasculitis, which results from the proliferation of rickettsiae in vascular endothelial cells. Direct rickettsial invasion of the nervous system has been described in patients with acute neurological complications (
). However, cranial nerve palsies occurring in the absence of clinical, laboratory, or imaging evidence of meningoencephalitis are thought to be a consequence of selective vasculitis affecting the respective nerves (
). In our report, the diagnosis has been definitively documented using reference methods including direct molecular detection on the swab eschar sample and indirect serological IFA assay and performed in an international referral center for rickettsioses (
Urban Family Cluster of Spotted Fever Rickettsiosis Linked to Rhipicephalus Sanguineus Infected with Rickettsia Conorii Subsp. Caspia and Rickettsia Massiliae.
). Swabbing of an eschar is much less painful and invasive than performing a biopsy from the eschar. For collecting this sample, a dry sterile swab must be rotated vigorously at the base of the eschar, right after the crust has been withdrawn (
). In the case of a dry eschar lesion, a wet compress previously soaked with sterile water should be placed on the inoculation eschar for 1 minute before swabbing to increase the quantity of material swabbed. Moreover, the crust can also be used for rickettsial diagnosis (
). Thus, this technique may be performed rapidly, either at the bedside or in outpatient settings. Moreover, results can be obtained quickly soon after the samples are sent to a laboratory where a qPCR diagnosis is feasible. This method has shown encouraging results for the detection of different Rickettsia species infecting humans in several countries (
). Although corticosteroids were administered in our case, as in other cases of facial nerve palsy of other or unknown origins, their use is still debated today (
The reemergence of rickettsial infections is occurring in many regions of the world owing to human travel and environmental changes; thus, clinicians should be aware of the complications associated with the disease. This case emphasizes the importance of considering MSF in the differential diagnosis of a patient with fever, rash, and facial nerve palsy in an endemic area. A prompt diagnosis is fundamental because early antibiotic treatment significantly improves the outcome of the disease.
Disclosures
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Acknowledgments
The authors wish to thank the patient's family for accepting the publication of this case report.
Ethical approval
Written informed consent was obtained from the patient's family for publication of this case report.
References
Arican Pinar
Olgac Dundar Nihal
Gencpinar Pinar
Cavusoglu Dilek
Efficacy of Low-Dose Corticosteroid Therapy Versus High-Dose Corticosteroid Therapy in Bell's Palsy in Children.
Urban Family Cluster of Spotted Fever Rickettsiosis Linked to Rhipicephalus Sanguineus Infected with Rickettsia Conorii Subsp. Caspia and Rickettsia Massiliae.
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