A rare case of non-wound tetanus mimicking botulism successfully managed in the ICU

Abstract

Background

Tetanus and botulism are neurotoxin-mediated diseases caused by Clostridium species but differ in their clinical manifestations and mechanisms of paralysis.

Case

A 36-year-old woman presented with presented with rapidly progressive trismus, dysarthria, and facial paresthesia without an identifiable wound. Neuroimaging was normal. She had undergone laser eye surgery two days earlier and consumed home-canned food two weeks before admission. One month prior, her house had been flooded, and she recalled possible minor hand injuries sustained during post-flood cleaning. Given the typical rigidity and absence of focal neurological lesions, tetanus was suspected. Human tetanus immunoglobulin (HTIG, 500 IU intramuscularly) and intravenous metronidazole were administered, leading to complete resolution of symptoms within 24 h.

Conclusion

This case illustrates that even minimal or unnoticed injuries can serve as a portal of entry for Clostridium tetani. Non-wound tetanus should be considered in patients presenting with trismus and cranial symptoms, even when no wound is apparent.

Introduction

Tetanus is a life-threatening but preventable neurological disorder caused by tetanospasmin, a potent neurotoxin produced by Clostridium tetani [1], [2]. The toxin blocks inhibitory neurotransmitter release, resulting in sustained muscle rigidity and spasms. Although traditionally associated with contaminated wounds, cases of “non-wound” or “cryptogenic” tetanus have been described in which no clear entry site can be identified [3]. Botulism, another neurotoxin-mediated disease caused by Clostridium botulinum, produces a contrasting clinical picture of descending flaccid paralysis through presynaptic blockade of acetylcholine release [4]. Because of overlapping cranial nerve findings, early-stage tetanus can mimic botulism. Accurate differentiation is crucial, as management differs substantially.

Case presentation

A 36-year-old female nurse presented to the emergency department of a tertiary care hospital in Türkiye, a middle-income country, with rapidly progressive symptoms developing within 12 h, including trismus, neck stiffness, dysarthria, and perioral paresthesia. She was fully conscious and oriented (GCS 15). Neurological examination revealed masseter rigidity but no focal deficits. Cranial MRI and CT angiography were unremarkable.

She denied recent trauma, injections, or dental procedures. However, she had undergone laser eye surgery two days earlier and consumed home-canned vegetables approximately two weeks prior. On further questioning, she recalled that one month earlier, her house had been flooded, and she had engaged in prolonged cleaning work during which she may have sustained unnoticed hand punctures while handling debris.

Her last documented tetanus toxoid vaccination had been in 2018. Earlier vaccination history was unavailable. On admission, a booster dose of tetanus toxoid was administered. Empirical therapy with intravenous metronidazole (500 mg every 8 h) and intramuscular human tetanus immunoglobulin (500 IU) was initiated.

Within 24 h, trismus and dysarthria improved dramatically, with complete symptom resolution by the following day. Laboratory investigations revealed mild leukocytosis (11.2 × 10⁹/L) and elevated CK (479 U/L), while inflammatory, renal, and hepatic markers remained normal. She was monitored in the ICU for 48 h and discharged asymptomatic.

Discussion

This case demonstrates the diagnostic challenge of differentiating tetanus from botulism in patients presenting with cranial involvement and no obvious wound. The absence of descending paralysis, preserved sensorium, and rapid clinical improvement following HTIG supported the diagnosis of early generalized tetanus [1], [5].

Botulism was considered in the differential diagnosis because of the presence of cranial symptoms, including dysarthria, and a history of home-canned food consumption in the absence of an obvious wound. However, unlike botulism, the patient had preserved consciousness, increased muscle tone, and no evidence of descending flaccid paralysis. Misdiagnosis as botulism could have delayed the administration of human tetanus immunoglobulin, potentially allowing progression to generalized tetanus with respiratory or autonomic complications.

“Non-wound tetanus” represents a well-documented but often under-recognized entity, typically associated with trivial or unnoticed trauma [3]. In this patient, minor dermal abrasions sustained during post-flood cleaning likely served as the inoculation point for C. tetani spores. Such exposures are plausible in environments where soil contamination and inadequate immunization coverage persist.

Metronidazole is preferred over penicillin for antimicrobial therapy, as β-lactams may exacerbate GABA antagonism [5]. ICU management is vital for airway monitoring and detection of autonomic instability [2], [6].

Differential diagnostic considerations
Feature	Tetanus	Botulism
Mechanism	Disinhibition via GABA blockade	Acetylcholine release blockade
Muscle tone	Spastic rigidity	Flaccid paralysis
Progression	Localized → generalized	Cranial → descending
Reflexes	Hyperreflexia	Hyporeflexia
Pupils	Normal	Dilated, sluggish
Treatment	HTIG + Metronidazole	Botulinum antitoxin
Incubation period	Days to weeks after minor or unnoticed injury	Hours to days after toxin ingestion

The patient’s rapid resolution after HTIG therapy reinforces the importance of early recognition and treatment, even in cases without an apparent entry site.

Conclusion

Tetanus should remain in the differential diagnosis for acute trismus and dysarthria, even when no wound is visible. Environmental exposures such as post-flood cleaning may constitute overlooked risk factors for non-wound tetanus. Early recognition and prompt administration of HTIG are essential for favorable outcomes.

Author Statement

All authors confirm that they have made substantial contributions to the conception, drafting, and critical revision of this manuscript.

The authors declare that the manuscript is original, has not been published previously, and is not under consideration for publication elsewhere.

All authors have reviewed and approved the final version of the manuscript and agree to be accountable for all aspects of the work.

CRediT authorship contribution statement

Hasan Basri Yapici: Writing – original draft, Supervision, Resources, Project administration, Conceptualization. Erdem Yalcinkaya: Writing – review & editing, Visualization, Methodology, Funding acquisition, Formal analysis, Data curation, Conceptualization. Umut Sabri Kasapoğlu: Resources, Methodology, Investigation, Data curation. Tamer Begüm: Writing – review & editing, Writing – original draft, Formal analysis.

Ethical approval

Written informed consent for publication of this case report and accompanying materials was obtained from the patient. The study was conducted in accordance with the principles of the Declaration of Helsinki.

Consent

Written informed consent for publication of this case report and accompanying materials was obtained from the patient. The study was conducted in accordance with the principles of the Declaration of Helsinki.

Copyright and License

The authors confirm that this manuscript is original, has not been published previously, and is not under consideration elsewhere. All authors agree to transfer copyright to the journal upon acceptance for publication.

Declaration of Competing Interest

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.