Botulism -cause, clinical features, complications and treatment Custom Search Botulism is a disease caused by toxins produced by bacteria known as Clostridium botulinum. The bacteria are normally found in soil. They are anaerobic which means they thrive when there is very little oxygen. They are known to produce seven types of toxins named A to G. The toxin is very potent. Less than one milligram can kill a human being. The bacteria form spores which are heat resistant. Infection can result from ingestion of contaminated food or by absorption of toxin from wound infected with the bacteria. Improperly canned food items are the usual source of food borne infection. The toxin is absorbed from the intestine and enters blood stream. It acts on nerve endings and prevents release of the neurotransmitter called acetylcholine which is necessary for the contraction of muscles. Thus the toxin causes paralysis of muscles. The food containing the toxin may look and taste normal. Infant botulism occurs in babies usually younger than six months. The organisms living in the intestine produce the toxin which is absorbed. Honey is known to contain spores of the bacteria and can cause the disease. Hence it is preferable not to give honey to infants up to one year of age. The toxin can be released as an aerosol in acts of bio-terrorism. Symptoms and signs: Infant botulism presents with constipation and decreased muscle tone causing flaccidity of limbs. Other features are week cry, poor sucking, pooling of secretions in month and generalized weakness. Paralysis of cranial nerves can occur. Food borne disease usually manifests within 36 hours of consuming contaminated food. Initially there may be lethargy. Drooping of eyelids, dilated pupils and double vision resulting from paralysis of cranial nerves occur later. Difficulty in swallowing and speaking occur due to paralysis of lower cranial nerves. Later paralysis of limb muscles develops. Death can occur from paralysis of respiratory muscles. Patients are usually free from fever unless there is secondary bacterial infection. Paralysis is usually symmetrical and proceeds from above downwards. Patients have normal sensorium until respiratory failures causes hypoxia and affects brain function. The brain stem is more severely involved in botulism causing four Ds.-Dysphonia (diminished voice), Dysphagia (difficulty in swallowing), Dysarthria (difficulty is speaking) and Diplopia (double vision). Laboratory findings: The toxin can be demonstrated in stool, serum, vomited material or in the gastric fluid obtained by aspiration. Suspected food should also be sent for analysis. Cerebrospinal fluid examination is usually normal. Electromyography may be helpful. Other causes of paralysis like Polio, Diphtheria, tick paralysis, myasthenia gravis and Guillain-Barre syndrome should be considered. Complications: Aspiration pneumonia and respiratory paralysis are the usual complications. Treatment: Specific antitoxin derived from horses or humans should be given. Supportive therapy in the form of intravenous fluids, tube feeding and ventilator support for respiratory failure may be required. Custom Search
Page last reviewed on 28th May 2011
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