Favism: symptoms, causes, diagnosis, treatment, and prevention

Favism is a disease caused by red blood cell glucose-6-phosphate dehydrogenase (G6PD) deficiency (G6PD deficiency). On the basis of genetic G6PD deficiency, contacting broad beans and their processed products, people may be with acute hemolysis, leading to hemolytic anemia or jaundice. However, the specific hemolytic mechanism is unknown. Therefore, children suffering from favism should keep away from broad beans and their processed products.

favism

Causes

The causes of the disease are quite complex. Favism occurs only in people with G6PD deficiency, but not all of them, even having taken broad beans. There is no proportional relationship between the degree of hemolysis and anemia and the amount of intake of broad beans. In addition to red blood cells lacking G6PD, favism may also be associated with other factors. Favism is X-linked recessive genetic disease, mainly in men, high incidence in children, mostly under 5 years of age, and less common in adults.


Signs and symptoms

If children have the following signs and symptoms after contacting broad beans, parents should pay attention.

  • Gastrointestinal symptoms: vomiting, diarrhea, abdominal pain.
  • Urinary system symptoms: dark brown urine, oliguria or anuria.
  • Skin symptoms: pale or pale yellow skin, accompanied by jaundice.
  • Systemic symptoms: chills, fever, severe systemic failure, weak and fast pulse, drop in blood pressure, mental retardation or irritability, coma.

Special attention: children under the age of 5 years must be careful with exposing to broad beans for the first time. Once they have the symptoms: fever, abdominal pain, pale skin, dark urine, and other symptoms, parents should take them to see a doctor immediately.


Diagnosis

1. Blood examinationg:

  • Sharply decreased hemoglobin,down to 100g /L or less in severe conditions
  • Erythrocyte down to 0.5 x 1012/L or less
  • Increased significantly reticulocytes > 0.20
  • Increased visible nucleated red blood cells in peripheral blood smear
  • Increased white blood cell counts up to (10 - 20) x 109 / L, or characterized by leukemia
  • Normal or increased platelet counts

2. Bone marrow examination:

  • Increased sharply red blood cells, granulocytes. The younger the patient, the more obvious the increased granulocytes
  • Increased sharply polychromatic erythroblasts and acidophilus normoblasts

3. Urine examination:

  • Yellow urin,
  • Occult blood test positive rate up to 60% - 70%,
  • Positive visible albuminous cells, red blood cells and tubule cells, urobilinogen and urobilin .

4. Increased serum free hemoglobin, decreased haptoglobin.

5. Reduced glucose-6-phosphate dehydrogenase activity.


Treatment

At present, blood transfusion is the most effective treatment for acute attack of favism, followed by correction of acidosis and renal failure for patients with mild to moderate hemolysis by rehydration.

  • Blood transfusion: Favism may result in acute hemolysis, and severe anemia. Blood transfusion is the most effective treatment measure. In severe conditions, repeated blood transfusion is necessary. The G6PD check is necessary to avoid G6PD deficiency in blood supply, so as to be far away from a second hemolysis.
  • Adrenal cortex hormones: Mainly immunosuppressive effects, give early, large-dose, and short-term medications.
  • Correcting acidosis: Favism is often accompanied by acidosis. For severe patients, only blood transfusion is not enough to take patients out of danger. Active correcting the acidosis may be necessary.
  • Rehydration: More water or fluid helps patients to improve microcirculation, maintain an effective blood circulation, and promote renal excretion of acid and excretion of hemoglobinuria.
  • Preventing acute renal failure: Maintaining water and electrolyte balance prevents acute renal failure.
  • Symptomatic treatment: If complicated infections may aggravate hemolysis, patients need to actively deal with complications.

Prevention

In addition to broad beans, some drugs may also cause the disease, such as antimalarial drugs (primaquine, quinine, etc.), antipyretics (aminopyrine, phenacetin, etc.), sulfonamides, naphthalene (mothball), and some herbal medicines.

Patients and their family should be fasting from broad beans and their processed products, and avoid exposing to broad bean pollen. Breastfeeding mothers should also be fasting from broad beans and their processed products.

Parents were required for routine tests of hemolytic genetic disease before giving birth to children. Patients with favism should tell their doctors to avoid the use of drugs that may lead to hemolytic.


Warning

Prohibitions:

  • Sulfadiazine
  • Sulfamethoxazole
  • Sulfapyridine
  • Sulfacetamide
  • Furazolidone
  • Furantoin
  • Primaquine
  • Pentaquine 
  • Nitroimidazole
  • Isosorbide dinitrate
  • Nifepine
  • Acetanilide
  • Phenylhydrazine
  • Thiazosulfone
  • Toluidine blue
  • Nalidixic acid
  • Furacilin
  • Methylene blue
  • Naphthalene
  • Pearl powder

Cautions:

  • Streptomycin
  • Chloramphenicol
  • Sulfafurazole
  • Sulfaguanidine
  • Sulfamonomethoxinum
  • Sulfamylon
  • Trimethoprim
  • Colchicine
  • Chloroquine
  • Quinine
  • Isoniazid
  • Pyrimethamine
  • Phenylbutazone
  • Probenecid
  • Aspirin
  • Acetaminophen
  • Indomethacin
  • Phenacetin
  • Nimesulide
  • Diclofenac sodium
  • Ibuprofen
  • Aminopyrine
  • Phenytoin
  • Levodopa
  • Artane
  • Quinidine
  • Procainamide
  • Antazoline
  • Diphenhydramine
  • Vitamin C
  • Vitamin K3
  • Vitamin K4
  • Chloroguanidum hydrochloride
  •  Aminobenzoic acid
  • Tripelennamine
  • Aminophylline
  • Camphor
  • Bear gall
  • Peppermint
  • Bezoar