Unilateral lateral rectus palsy: An uncommon presentation of Scrub Typhus

Ete K, Habung H and Deshpandey JJ

Published on: 2023-10-04

Abstract

Scrub typhus is a zoonotic disease caused by rickettsia [1], Orientia tsutsugamushi. It is transmitted to humans by an arthropod vector of Trombiculidae family. It usually presents with acute febrile illness with or without multiorgan failure. Central nervous system involvement [2] usually presents with acute meningoencephalitis, however isolated cranial nerve palsy are rare.

Keywords

Scrub Typhus; Abducens Nerve; Eschar

Introduction

Here we present a case of young female who presented with isolated abducens nerve palsy. Scrub typhus is endemic to geographical region called the tsutstugamushi triangle which includes and asia and pacific Islands. Increase in cases is maybe due to urbanisation into rural areas. Disease is usually associated with fever, rash, myalgia and lymphadenopathy. A necrotic eschar at the inoculating site of the mite is pathognomic of the disease. Cough with infiltrates on chest x rays are also common manifestation of the disease. Complications usually occur at first week of illness. It includes acute renal failure, hepatic failure, shock due to sepsis and myocarditis, neurological complications like meningoencephalitis. Death is due to delayed diagnosis. Early starting of doxycycline or azithromycin reduces mortality and morbidity.

Case Report

A 23 years old female living in Arunachal Pradesh, with no previous comorbidities, presented with complaints of fever, headache and myalgia of 3 days duration. On examination an eschar was found in right arm.

Figure 1: Eschar.

All other systemic examinations were within normal limits. Her routines showed mild thrombocytopenia, mildly elevated liver enzymes. Scrub typhus IgM was positive. All other investigations were within normal limits. She was started on doxycycline, antipyretics and other supportive measures. Fever gradually subsided. On day 2 of her hospital stay, she complained of diplopia. On examination she had lateral rectus palsy of right eye. There was no signs of meningitis, or features of raised intracranial tension.

Figure 2: Right sided lateral rectus palsy.

MRI brain and orbit was done which was within normal limits. CSF studies showed mild lymphocytic pleocytosis. Patient was continued with doxycycline and her lateral rectus palsy improved by Day 10.

Discussion

Neurological manifestation of scrub typhus include meningitis, encephalitis, seizures or stroke [2]. But isolated abducens nerve palsy is rare [3]. Short febrile illness with abducens nerve palsy should prompt clinician to keep scrub typhus as one of the differential diagnosis.

Possible mechanism postulated is scrub typhus induced vasculitis and injury to vasa vasorum.[6] Some case report of isolated 3rd and 8th cranial nerve palsy have also been documented.[4] In spite of starting Doxycycline our patient developed 6th nerve palsy on second day of doxycycline therapy.

Conclusion

For acute febrile illness with isolated cranial nerve palsy, in an endemic area, a differential diagnosis of scrub typhus must be kept in mind. Early diagnosis and institution of doxycycline has been found to be very effective in scrub typhus.

References