At 44, the man seemed to recover well after a double lung transplant at Northwestern Memorial Hospital in Chicago, Illinois. One week after surgery, however, the patient, whose own lungs had been ruined by the inflammatory lung disease sarcoidosis, was confused and became delirious. Although a brain scan found nothing wrong, the tests showed that the amount of ammonia in his blood had enriched and continued to rise even after dialysis to remove the toxin. Forty days after his surgery, he died.
Now, a new study involves bacteria that normally live in the urinary tract as the cause of the deadly disease of man and the death of other lung transplant patients. The work suggests a way to treat a rare but fatal complication of organ transplantation and cancer treatment.
Although our body normally produce small amounts of ammonia when it breaks down protein, liver enzymes convert it into a safer compound, urea, which is excreted in urine. In some recipients of organ transplants and cancer patients, however, the amount of ammonia in the explosion of blood. Although this condition, known as hyperammonemia name is unusual, "when it took place, it was disastrous," said Mark Wylam pulmonologist at the Mayo Clinic in Rochester, Minnesota. The brain swells, and the patients fall into a coma. "The end of the test is that they die," he said.
Not only is resistant to treatment and usually fatal hyperammonemia, but the cause was also difficult to achieve. In 2013, Wylam and colleagues discovered the likely culprit in one case, a woman of 64 years who died of hyperammonemia after a double lung transplant. They found that his blood and tissues were positive for a type of bacteria, Mycoplasma hominis , which often causes benign genital infections in women.
But the man who died at Northwestern Memorial hospital showed no signs of M. hominis Bharat Ankit thoracic surgeon at Northwestern University Feinberg School of Medicine in Chicago and colleagues found. instead, they detected a different bacterium, Ureaplasma urealyticum in the blood of man and in samples of bladder, spleen, liver and lungs. The team then tested the tissue of three other lung transplant patients who were dead hyperammonemia, including the patient studied by Wylam and colleagues. All three showed signs of infection U. urealyticum , or a close microbe U. parvum . In contrast, 20 lung transplant recipients who develop hyperammonemia were negative for three microbes, the researchers report online today in Science Translational Medicine .
The researchers also checked for bacteria in two lung transplant recipients who had hyperammonemia, but were still alive. Both patients transported U. urealyticum or U. parvum bacteria, and both recovered after antibiotic treatment.
Wylam, who was not connected to the new study, says the results are conclusive. "They showed that U. urealyticum can also cause these unexplained cases of hyperammonemia." The paper recommends testing the lung transplant recipients who have to hyperammonemia Ureaplasma infection. The study also provides guidance on the treatment of the condition. Although man Bharat and his colleagues studied had received azithromycin antibiotic, bacteria may have become resistant to it. Microbes are vulnerable to three families of antibiotics, so a combination of drugs would be a better choice to avoid resistance, said Bharat.
About two-thirds of us Ureaplasma bacteria living in our urinary system, where they feast urea decomposing to produce energy and release ammonia as a byproduct. Why bacteria may trigger sepsis and death are not clear. Cancer patients and transplant recipients suppressed immune system and microbes could benefit from their weakened defenses. However, another possibility is appeared when Bharat and colleagues found that the lungs from a donor already contained bacteria before organs were transplanted in the recipient. Thus, the donor organs could deliver germs to patients who develop hyperammonemia.
Ureaplasma microbes are difficult to diagnose because they do not like to grow in cultures that hospitals often use to identify the culprits in bacterial infections. unrecognized infections may be responsible for additional hyperammonemia cases and even other diseases, says Bharat. For example, he notes, the microbes could be the cause of the disease in patients with malnutrition. "These organisms could be a bigger problem," he said.
0 Komentar