November 30, 2015
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Botulism (cont.)

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What are botulism symptoms and signs?

The classic symptoms of botulism include

The classic symptoms may also be accompanied by other symptoms and signs such as

Constipation may occur. The doctor's examination may reveal that the gag reflex and the deep tendon reflexes like the knee-jerk reflex are decreased or absent.

Infants with botulism appear lethargic, weak, and floppy, feed poorly, become constipated, and have a weak cry and poor muscle tone. In infants, constipation is often the first symptom to occur.

These are all symptoms and signs related to the muscle paralysis that is caused by the bacterial neurotoxin. If untreated, these symptoms and signs may progress to cause paralysis in various parts of the body, often seen as a descending paralysis of the arms, legs, trunk, and breathing muscles that can lead to death.

How soon do symptoms appear?

In food-borne botulism, symptoms generally begin 18-36 hours after eating a contaminated food, but they can occur as early as six hours or as late as 10 days afterward.

What are risk factors for botulism?

The risk for developing botulism is increased by ingesting foods that may be improperly treated to kill C. botulinum bacteria and their spores (for example, some home-canning methods or a failure in a canning company's production of canned foods like tomatoes or fish) and to denature any toxins. Some honey preparations may contain small amounts of the bacterial spores; infants under the age of 1 year are at risk if they are given honey. Botulism risk is increased if wounds become contaminated with soil or fecal material.

How do health-care professionals diagnose botulism?

The patient's history and physical examination may suggest botulism, but these clues are usually not enough to allow a diagnosis of botulism. Symptoms of other diseases, such as a stroke, Guillain-Barré syndrome (another disease of muscle paralysis), and myasthenia gravis (which also causes weakness and eyelid drooping) can appear similar to those of botulism. Special tests may be needed to exclude these other conditions. These tests may include a brain scan, spinal fluid examination, nerve conduction test (electromyography, or EMG), and a Tensilon test for myasthenia gravis. However, if botulism is strongly suspected (for example, several patients with botulism symptoms who ate from the same home-preserved food container), samples should be obtained for a mouse inoculation test (see below) and then the patients should be treated immediately with botulism antiserum. These tests will help distinguish botulism from infections with Salmonella, E. coli, and other Clostridium species (tetani).

The most direct way to confirm the diagnosis is to identify the botulinum neurotoxin in the patient's blood, serum, or stool. This is done by injecting the patient's serum or stool into the peritoneal cavity of mice. An equal amount of serum or stool from the patient is treated with multivalent antitoxin and injected in other mice. If the antitoxin-treated serum- or stool-injected mice live while those injected with untreated serum or stool die, then this is a positive test for botulism and is called the mouse inoculation test. The bacteria can also be isolated from the stool of people with food-borne and infant botulism, but this is not a definitive test. However, stool cultures can help differentiate botulism from E. coli, Salmonella, and other infectious agents.

Medically Reviewed by a Doctor on 11/16/2015


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