Favismosis is an acute hemolytic anemia that occurs in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency after eating broad beans. Broad bean (viciafaba) is also known as bean yellow.
Fab bean disease is found in southwest, south, east and north my country, with the highest number in Guangdong, Sichuan, Guangxi, Hunan and Jiangxi. 70% of patients are under 3 years old and 90% are male. Adult patients are relatively rare, but there are also a few patients who first develop the disease in middle age or old age. Since G6PD deficiency is hereditary, more than 40% of cases have a family history. This disease often occurs in early summer when broad beans are ripe. The vast majority of patients become ill after eating fresh broad beans. This disease occurs sooner or later due to different climates in the north and south.
The incidence of favismosis is quite complex. For example, favismosis only occurs in people with G6PD deficiency, but not all G6PD deficient people will develop hemolysis after eating broad beans; people who have had favismosis eat broad beans every year, but not all The disease must occur every year; the degree of hemolysis and anemia in patients has no parallel relationship with the amount of broad beans eaten; the incidence rate in adults is significantly lower than that in children. It can be speculated that in addition to the lack of G6PD in red blood cells, there must be other factors related to the disease. It can be seen that the mechanism of hemolysis in favismosis is more complicated than drug-induced hemolytic anemia caused by G6PD deficiency, and remains to be further explored.
Clinical manifestations
The onset of favismosis is sudden, and hemolysis usually occurs within 1 to 2 days after eating fresh fava beans. The shortest time is only 2 hours, and the longest time can be 9 days. For those who become ill due to inhaling pollen, symptoms may appear within minutes. The length of the incubation period has nothing to do with the severity of symptoms. The degree and symptoms of anemia in this disease are mostly severe. Symptoms include general malaise, fatigue, chills, fever, dizziness, headache, anorexia, nausea, vomiting, abdominal pain, etc. The sclera is slightly jaundiced, and the urine is as colored as strong black tea or even soy sauce. Symptoms generally last for 2 to 6 days. The most severe cases show symptoms of acute circulatory failure and acute renal failure such as extremely pale complexion, systemic failure, weak and rapid pulse, decreased blood pressure, mental dullness or restlessness, oliguria or anuria, etc. If anemia, hypoxia and electrolyte imbalance are not corrected in time, it can lead to death; however, if appropriate treatment can be given in time, there is still hope for improvement.
Diagnosis, prevention and treatment of broad beans
Sudden onset of severe acute hemolytic anemia after eating fresh broad beans is the main characteristic of favis. It depends on the season of onset, area of ??onset, age of the patient, Gender and family history, etc., it is generally not difficult to make a diagnosis. If it can be proven that the patient's red blood cells lack glucose-6-phosphate dehydrogenase (G6PD), the diagnosis will be clearer. In low-incidence areas, the disease is easily overlooked and missed. The hemolysis of favismosis is often rapid and massive, and the anemia is severe, requiring timely blood transfusion or transfusion of packed red blood cells. Most patients' conditions improve immediately after 1 or 2 blood transfusions. Pay attention to the balance of water and electrolytes. Drink plenty of fluids or intravenous fluids to prevent acute renal failure and potassium toxicity. For those with low blood pressure, low molecular weight dextran can be added to improve blood circulation. Patients and those with known G6PD deficiency should avoid eating broad beans or coming into contact with broad bean flowers.