What is Favism? Favism Diagnosis

Favism? What is favism? Today I will give you a detailed introduction:

fabism

It is a disease caused by glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, characterized by sudden acute intravascular hemolysis after eating fresh broad beans in the case of hereditary glucose-6-phosphate dehydrogenase (G-6-PD) deficiency.

mechanism:

People with genetic defects in red blood cell glucose-6-phosphate dehydrogenase (G6PD) will develop acute hemolytic anemia, favism, after eating fresh broad beans or coming into contact with broad bean pollen. The pathogenic mechanism is not yet very clear. It is known that sensitive red blood cells with genetic defects cannot provide enough NDPH to maintain the reducing property (antioxidant effect) of reduced glutathione (GSH) due to the defect of G6PD. When encountering certain factors in broad beans, the red blood cell membrane is oxidized and a hemolytic reaction occurs. G-6-PD has the function of protecting normal red blood cells from oxidative damage. Fresh broad beans are a strong oxidant. When G-6-PD is deficient, red blood cells are destroyed and disease occurs.

Clinical manifestations:

In the early stage, there are chills, mild fever, dizziness, fatigue, lack of appetite, and abdominal pain, followed by jaundice, anemia, hemoglobinuria, and soy sauce-colored urine. After that, the body temperature rises and fatigue worsens, which can last for about 3 days. At the same time as the hemolytic anemia appears, vomiting, diarrhea, and abdominal pain increase, the liver is enlarged, liver function is abnormal, and about 50% of patients have splenomegaly. In severe cases, coma, convulsions, and acute renal failure can be seen. If emergency treatment is not timely, death is often caused within 1 to 2 days.

diagnosis:

The disease is inherited through incomplete sex-linked dominant inheritance. The G-6-PD gene is on the X chromosome. Most patients are male, with a male-to-female ratio of about 7:1. Within a few hours to a few days (1 to 3 days) after eating raw broad beans, they suddenly develop fever, dizziness, irritability, nausea, and soy sauce-like or wine-colored urine. Generally, they can recover on their own after 2 to 6 days of onset, but severe cases can be life-threatening due to circulatory failure if not promptly treated. It can be diagnosed through medical history and methemoglobin reduction test (reduction rate greater than 75%), especially the fluorescent spot test.

1. Have a history of eating green broad beans or inhaling broad bean pollen.

2. Clinical features: ① The incubation period is from several hours to 48 hours. ② Symptoms of poisoning: In the early stage, there are chills, mild fever, dizziness, fatigue, lack of appetite, abdominal pain, followed by jaundice, anemia, hemoglobinuria, and soy sauce-colored urine. After that, the body temperature rises, fatigue and weakness worsen, and it can last for about 3 days. ③ Laboratory examination: The reduction rate of methemoglobin reduction test (MHb) in normal people is >75% (colorimetric method), the reduction rate of MHb in patients with favism is 31%~74% (heterozygous inheritance), and the reduction rate is <30% (homozygous type); the content of denatured globin bodies (Hernz bodies) in the blood can be higher than 5% (normal is 0~0.28%). First aid treatment: 1. Artificial vomiting. 2. Gastric lavage with 1:5000 potassium permanganate solution. 3. Oral catharsis with 25% magnesium sulfate. 4. Give high doses of glucocorticoids. 5. If necessary, exchange blood or transfuse fresh blood. 6. Alkalinize urine, give appropriate intravenous fluids and use diuretics, and actively prevent and treat hemolytic uremic syndrome. 7. Symptomatic treatment.