Murine typhus associated abducens nerve palsy

Dear Editor,

Murine typhus, causes by Rickettsia typhi, manifests mild non‐specific symptoms, such as fever, chills, headache, myalgia. Some may complicate with acute renal failure, spontaneous splenic rupture, acute respiratory failure or aseptic meningitis [1]. We reported a murine typhus patient with a rare complication of left side abducens nerve palsy.

The 39‐year‐old healthy female suffered from high fever (38.7 °C), chillness, severe headache and muscle soreness for 5 days. Physical examination revealed only mild skin rash over trunk and negative meningeal signs. Lab data revealed leukocyte count of 4700/μl with 73.8% neutrophils, hemoglobin of 11.7 g/dl, a platelet count of 242,000/μl, total bilirubin of 0.4 mg/dl, aspartate aminotransferase of 204 IU/L, alanine aminotransferase of 178 IU/L, alkaline phosphatase of 118 IU/L, blood urea nitrogen of 6 mg/dl, creatinine of 0.6 mg/dl, C‐reactive protein of 55.35 mg/L. Abdominal computed tomography and ultrasonography disclosed no special abnormality. First serology tests for Q fever, scrub typhus, murine typhus, and Cryptococcus were negative. Blood culture for bacteria was sterile. HBsAg and Anti‐HCV were also negative.

Because her job was a Chinese herbs sale, she needs to go to a warehouse to take herbs where found some rats inside. She was treated with oral doxycycline 100 mg bid because of the tentative diagnosis of murine typhus. Her clinical condition and liver dysfunction were improving gradually. However, her left eye had limited outward movement with mild nystagmus and double vision developing gradually while outward gazing without other neurological symptoms on day 7 of hospitalization. Fundoscopy showed normal finding. Abducens nerve palsy was noted but her brain computed tomography and magnetic resonance imaging had no significant finding. Lumbar puncture and cerebrospinal fluid (CSF) study were refused by patient. The neurologist recommended steroid therapy for the progressive disease. Because the patient hesitated steroid therapy, we kept supportive care. Diplopia and abducens nerve palsy recovered gradually under doxycycline treatment. Convalescence serum yielded indirect immunofluorescence assay (IFA)‐IgG 1:320 and IFA‐IgM 1:80 for murine typhus by Taiwan Center of Disease Control and Weil–Felix test showed OX19 and OX2 > 1:160 and OXK 1:80. The final diagnosis of murine typhus was confirmed.

To our knowledge, our case is the first to present isolated abducens nerve palsy as a late complication of murine typhus without obvious meningoencephalitis (Table 1) [[2], [3], [4]]. Comparing to prior reports, four cases had obvious meningoencephalitis. Another Taiwanese case without meningoencephalitis got right abducens nerve palsy after lumbar puncture, which may be correlated to CSF hypotension in the early phase of disease (day 2). Considering the reason for nerve damage, some cases have pointed Guillain‐Barré syndrome as the complication of post‐rickettsial infection. The second assumption was the acute motor and sensory polyneuritis with rapidly reversible distal conduction failure after rickettsial infection. However, in the situation of above two hypotheses, patients usually have other neurological manifestations such as hyporeflexion, weakness of lower limbs, which our patient did not have. The third mechanism may be microinfarction of the abducens nerve, associated with coagulation abnormity caused by rickettsia. The final mechanism was the neurological irritation by raised intracranial pressure and we think this is the most possible reason to interpret that our case only had isolated abducens nerve palsy without other severe complication.

Table 1.

Reported cases of murine typhus (R. typhi) related abducens nerve palsy.

Clinical and laboratory data	Present case	Simon NG, et al. [2]	Masalha R, et al. [3]	Hsu CH, et al. [4]	Moy WL, et al. [5]	Moy WL, et al. [5]
Infection Country	Taiwan	Australia	Israel	Indonesia	Singapore	Indonesia
Age (years)	39	20	22	31	39	27
Gender	Female	Male	Female	Male	Male	Female
Fever	+	+	+	+	+	+
Nerve involved	Abducens Left	Abducens Bilateral	Abducens Right	Abducens Right	Abducens Right	Abducens Bilateral
Days after onset	9	10	14	2	9	4
Headache	+	+	+	+	–	+
Nuchal rigidity	–	–	–	–	+	–
Photophobia	–	–	–	–	–	–
Imagine of brain	Normal	Normal	Normal	Normal	Normal	Meningoencephalitis
Other complication	Liver dysfunction	Seizure, Meningoencephalitis	Mild subacute meningoencephalitis	Liver dysfunction	Liver dysfunction, mild meningitis	Meningoencephalitis and ventilator associated pneumonia

Supporting information

Supplementary data

Supplementary data

Supplementary data related to this article can be found at https://doi.org/10.1016/j.kjms.2018.02.006.