Adult Intestinal Botulism

A very rare form of botulism, a rare acquired neuromuscular junction disease with descending flaccid paralysis caused by botulinum neurotoxins (BoNTs), and is due to intestinal colonization by Clostridium botulinum leading to toxin-mediated infection with toxemia.

Epidemiology

Exact prevalence is unknown. To date, about 20 cases have been reported.

Clinical description

The disease affects adults and older children. Clinical manifestations are similar to other forms of botulism (flaccid and symmetrical cranial nerve palsy, followed by symmetrical flaccid descending motor paralysis). Compared to foodborne botulism (see this term), the onset is generally gradual and less dramatic. In some cases, diarrhea due to C. difficile co-infection has been reported.

Etiology

The disease results from prolonged intestinal absorption of small quantities of BoNTs produced in situ by C. botulinum type A and B, or rarely by C.botulinum type C (one case) or by neurotoxigenic strains of C. baratiitype F or C. butyricum type E, that can temporarily colonize the intestinal tract. Colonization is generally associated with anatomical abnormalities of the gastrointestinal tract or alteration of protective endogenous microflora by broad-spectrum antibiotics following inflammatory intestinal disease or surgery. Some patients who underwent laparotomy for suspected appendicitis have shown worsening paralysis probably due to the post-surgical antibiotic therapy. Presence of Meckel's diverticulum may be a predisposing factor for intestinal colonization by C. butyricum.

Diagnostic methods

Diagnosis is based on clinical presentation. Confirmation of adult intestinal botulism is based on the detection of BoNTs in serum and stools. In addition, stools can be screened for BoNT-producing Clostridia. Diagnosis is also performed by demonstration of prolonged excretion of microorganisms and toxin in the stool in patients with sporadic botulism and no known contaminated food or wound.

Differential diagnosis

Differential diagnosis includes myasthenia gravis, Guillain-Barré syndrome (Miller Fisher syndrome), Lambert-Eaton syndrome and foodborne and wound botulism (see these terms).

Management and treatment

The antitoxin therapy must be associated with supportive care in an intensive care unit (ICU). Equine antitoxin treatment for adults has a half-life of 5-8 days. In Europe, the formulation currently available for adults is trivalent (anti A, B, E). A heptavalent (anti A to G) product is also available. In the USA, a bivalent (anti A, B) and a monovalent (anti E) antitoxin are available. Antibiotic therapy is ineffective on the toxin action and can exacerbate the neuromuscular blockade, but it is useful when secondary infections are present. In the severe forms, respiratory failure and paralysis may require ventilation for weeks as well as intensive care.

Prognosis

When treatment is administered early and with appropriate intensive care, the prognosis is generally good, no long-term side effects have been observed, and death resulting from respiratory failure is extremely rare. Complications can occur during hospitalization including nosocomial adverse events.