A construction worker in his 40s fell eight feet from a scaffold and had a compound fracture of his right leg. No one could have imagined where that would lead.

At the hospital, the fractured leg, which was covered with soil from the ground, was cleaned. The patient was put on preventive antibiotics to combat bacteria that may have contaminated the wound, and he underwent a series of surgeries.

The first was to stabilize the break by inserting metal pins into the bone above and below the fracture. Afterwards, the patient twice underwent debridement, surgical removal of tissue too damaged to heal. When the wound began to ooze cloudy fluid, the tissue was cultured and the patient given an antibiotic for the bacteria thought to be causing the infection.

The day after the second debridement, on the 16th day of hospitalization, the man complained of a sore throat and difficulty swallowing. His mouth and throat appeared normal, but he also seemed to be having difficulty enunciating.

The patient was switched to another medication in case he was having an allergic reaction to the antibiotic. We believed, though, that his throat was irritated and swollen from the airway tube inserted during general anesthesia for his surgeries. We ruled out a stroke with a CT scan, and consulted with ear-nose-throat and gastroenterology specialists, who recommended anti-fungal treatment for a possible yeast infection of the esophagus. The treatment didn't help. A subsequent endoscopy showed no yeast in the esophagus or stomach.

By the 22d day, the patient had dilated pupils that did not contract properly, blurred vision, could not fully open his eyes or smile, and had weakness in his facial muscles.

Solution:

A possible diagnosis of myasthenia gravis was considered, and the patient was treated with a course of intravenous immunoglobulin therapy. Again, there was no improvement.

But the partial paralysis was the key to his eventual diagnosis.

The contractor had developed a rare disease more commonly associated with improperly canned foods: botulism.

Botulinum is the most potent toxin known to medical science; the lethal dose for an adult human is about one 50-millionth of a teaspoon.

Botulinum toxin is made by a bacterium called Clostridium botulinum, which blocks transmission of electrical impulses from nerve cells to muscles. The muscle cell is paralyzed for weeks to months until a new neuromuscular junction grows.

It's typical for symptoms to be most profound in the head and face; difficulty swallowing is often described by patients as a sore throat. Paralysis of the pupils is present in botulism but is generally not in myasthenia gravis, an autoimmune disease in which antibodies are made that interfere with the functioning of neuromuscular junctions. In retrospect, that was an important clue to the diagnosis.

The bacterium wasn't detected in the original tissue culture because the organism dies once exposed to oxygen, making it nearly impossible to see under a microscope. It was discovered by another test in which mice are injected with serum or tissue from the wound to see if they become symptomatic.

Most cases of botulism occur after ingestion of improperly canned food, such as the commercial vichyssoise that killed a man in a notorious 1971 case. More rarely, the bacteria can actually grow in a patient's intestines and produce toxin that is absorbed into the body. Even more unusual is the case of the construction worker, in which the bacteria grow in a wound whose damaged tissue is poorly oxygenated. Only a small handful of wound botulism cases occur each year in the United States.

The only treatments are supportive care, which the patient received; antibiotics, which were given; debridement of the wound to remove the organisms, which was performed; and administration of botulinum antitoxin, which was not done.

The antitoxin is made by injecting toxin into horses and harvesting plasma from the animals that contains antibodies that prevent the paralysis. But horse serums can provoke major allergic reactions in humans, so there is significant risk for adverse reaction.

In any case, the medical literature on botulism suggests antitoxin is helpful if given early. The patient was already beginning to improve by the time he was diagnosed, so we opted not to give the antitoxin. Spontaneous recoveries are slightly unusual, but it all depends on how much toxin was produced and absorbed.

After 97 days in the hospital, the patient went home.

Robert Fischer is division chair of infectious diseases at Einstein Healthcare Network; Sushma Ramprasad, MD, is a fellow in infectious diseases.