Neuro-ophthalmic findings in botulism type B

A 43-Day-Old Male With Respiratory Distress and Acute-Onset Hypotonia

A 43-day-old, full-term, previously healthy male presented with decreased activity and oral intake. He was found to be grunting and hypoxemic on examination, and a respiratory pathogen panel was positive for rhinovirus. He was diagnosed with presumed bronchiolitis. His neurologic exam on admission was normal. Because of respiratory failure, he was escalated from high-flow nasal cannula to bilevel positive airway pressure upon admission and he was started on ceftriaxone and vancomycin while awaiting culture data. On hospital day 6, he required escalation of respiratory support. His examination at that time was notable for new hypotonia of his bilateral upper and lower extremities, sluggish pupils, bilateral exotropia, intermittent vertical nystagmus, and an absent Moro reflex. He developed a focal seizure and a computed tomography of the brain demonstrated simple right otomastoiditis. The seizure was attributed to a serum sodium of 113 mmol/L in the setting of syndrome of inappropriate antidiuretic hormone secretion, thought to be secondary to viral bronchiolitis. However, as the patient's sodium was corrected to a normal range, he continued to have neurologic deficits on examination. Given his persistent hypotonia and respiratory failure, atypical for the expected course of viral bronchiolitis, the patient underwent an extensive neurologic and infectious workup, which ultimately revealed a surprising diagnosis.

Pearls and Oysters: Reversible Postpartum Pseudo-Coma State Associated With Magnesium Therapy: A Report of 2 Cases

Magnesium (Mg) competes with calcium in normal synaptic transmission, inhibiting neurotransmitter release. As a drug, it is usually given as a treatment for eclampsia and pre-eclampsia. Two eclamptic pregnant women treated with Mg developed a pseudo-coma state immediately after emergency Caesarian Section. The clinical presentation was flaccid quadriparesis, areflexia, an absence of absent respiratory effort and vestibular-ocular reflexes, but with preserved pupillary responses. Decremental responses on repetitive nerve stimulation were found in both women. Recovery was obtained after cessation of the Mg. The persistence of pupillary reflexes in the absence of reflexes involving striated muscles was an important clinical clue, indicating neuromuscular junction dysfunction.

Characteristics of pupil palsy in miller-fisher syndrome: case reports and review of the literature

Pupil palsy has been a frequent finding in Miller Fisher syndrome (MFS), but its clinical characteristics have not been clearly defined. The basis for differential diagnosis with other diseases with pupil palsy has also remained vague. We report cases of four MFS patients with bilateral pupil palsy and specify pupil characteristics of light-near dissociation (LND), cholinergic super-sensitivity, vermiform movements, and prognosis. We conducted a literature review to compare with our cases and investigate common findings of pupil palsy in MFS patients. We suggest that the acute generalized pupil palsy without vermiform movements can serve as a key finding for the diagnosis of pupil palsy associated with MFS. However, the presence of LND and cholinergic super-sensitivity was not distinctive clinical findings in MFS patients who had pupil palsy and did not prove useful for differential diagnosis. The prognosis of pupil palsy in MFS patients was good in our 4 cases and the literature review.

Foodborne Botulism: Clinical Diagnosis and Medical Treatment

Botulinum neurotoxins (BoNTs) produced by Clostridia species are the most potent identified natural toxins. Classically, the toxic neurological syndrome is characterized by an (afebrile) acute symmetric descending flaccid paralysis. The most know typical clinical syndrome of botulism refers to the foodborne form. All different forms are characterized by the same symptoms, caused by toxin-induced neuromuscular paralysis. The diagnosis of botulism is essentially clinical, as well as the decision to apply the specific antidotal treatment. The role of the laboratory is mandatory to confirm the clinical suspicion in relation to regulatory agencies, to identify the BoNTs involved and the source of intoxication. The laboratory diagnosis of foodborne botulism is based on the detection of BoNTs in clinical specimens/food samples and the isolation of BoNT from stools. Foodborne botulism intoxication is often underdiagnosed; the initial symptoms can be confused with more common clinical conditions (i.e., stroke, myasthenia gravis, Guillain–Barré syndrome—Miller–Fisher variant, Eaton–Lambert syndrome, tick paralysis and shellfish or tetrodotoxin poisoning). The treatment includes procedures for decontamination, antidote administration and, when required, support of respiratory function; few differences are related to the different way of exposure.

Penetrating keratoplasty in a California Brown Pelican

Fresh homologous penetrating keratoplasty (PK) was performed on the left cornea of a young adult female California Brown Pelican (Pelecanus occidentalis) for the treatment of vision-threatening corneal scarring and granulation tissue. The procedure appeared to be highly successful based on short-term clinical follow-up and histopathology results. However, the patient died from unrelated causes before long-term follow-up could be obtained.

Clostridium botulinum and the ophthalmologist: a review of botulism, including biological warfare ramifications of botulinum toxin

The anaerobic bacterium Clostridium botulinum causes disease by elaborating an extremely potent neurotoxin that inhibits release of acetylcholine at presynaptic nerve endings, thereby resulting in a descending flaccid paralysis and autonomic nervous system dysfunction. Possible ophthalmological effects of this neurotoxin are many and typically constitute the earliest manifestations of botulism. This review summarizes the medical literature on botulism with regard to historical perspective, epidemiology, clinical manifestations, and treatment. Ophthalmological findings of botulism are tabulated and their frequencies are provided. Finally, the bioterrorism/biologic warfare ramifications of botulinum toxin are briefly discussed.

Botulism: a case associated with pyramidal signs

Botulism is a widespread neuroparalytic disease that may be confused with other neurological disorders. As it is potentially lethal, clinicians are required to be aware of its diagnosis and management. We report a case of botulism complicated by pyramidal signs in a 35-year-old woman. Clinical aspects, differential diagnoses and therapeutic problems are discussed.

A practice pathway for the initial diagnostic evaluation of isolated sixth cranial nerve palsies

PURPOSE

To define a practice pathway for the evaluation of sixth-nerve palsies (SNPs) and to determine its cost-effectiveness and validity in a retrospective chart review.

METHODS

A Medline search of the English-language literature from 1966 to 1995 was performed to define the available clinical evidence and develop the practice pathway. The authors retrospectively reviewed 407 charts with the diagnosis of SNP seen at three centers. Information obtained included: etiologic diagnosis if known; development of new neurologic or ophthalmologic findings; and results and costs of neuroimaging studies, if performed.

RESULTS

Of the 407 patients, 98 underwent computed tomography scans and 212 underwent magnetic resonance imaging of the head. Eighty cases were non-isolated, 317 were isolated SNP, and ten could not be classified from chart information. Of the 317 cases of isolated SNP, 49 were classified as traumatic; 5, congenital; 158, vasculopathic; 63, nonvasculopathic; and 42, progressive or unresolved. Following the recommendations of the practice pathway, the 158 patients classified as having vasculopathic SNP would not have undergone neuroimaging studies, realizing a savings of $100,000 in this study population of 407 patients.

CONCLUSION

The recommendations of the practice pathway are supported by review of the literature and the retrospective review of these cases. However, a prospective study with a matched control group is needed to demonstrate regional and specialty-specific variations in care and to strengthen the clinical certainty of the pathway recommendations.

Transient tonic pupils in botulism type B

We report a 29-year-old woman who developed unilateral unreactive mydriasis and cycloplegia after 5 days of persistent constipation. During the next hours the patient complained of dry mouth and difficulties in swallowing food; iris and ciliary muscle palsies spread over the second eye. Ocular motility was normal and there were no clinical signs of neuromuscular involvement. Conventional electromyography and evoked muscle action potentials following repetitive nerve stimulation were normal; single-fiber electromyography showed normal jitter and absence of blocking. The diagnosis of botulism was considered as most likely, and the patient was given botulinum antitoxin. The post-treatment course was characterized by bilateral tonic pupillary reaction to near, sectoral iris contractions to light and pupillary constriction to 2 mm in 40 min following topical instillation of 0.1% pilocarpine. Ocular manifestations completely disappeared within 5 weeks. Botulism type B toxin was demonstrated in the pretreatment stool of the patient but not the serum.