OVERVIEW
Cold agglutinin syndrome is an autoimmune disease characterized by the occurrence of cutaneous microcirculatory disorders, or mild hemolytic anemia, as a result of cold agglutinin-induced erythrocyte agglutination in blood vessels at the ends of the limbs at low temperatures.
Etiology
The disease is divided into primary and secondary. The cause of primary cold agglutinin syndrome is unknown. Secondary cold agglutinin syndrome is divided into three cases: ① Acute type: may be infectious factors stimulate the clonal growth of lymphocytes, producing special cold agglutinin, seen in some viral diseases, such as Mycoplasma pneumoniae infection, rubella, pericarditis, etc.. ② Subacute type: seen in certain lymphoreticular system malignant tumors and systemic lupus erythematosus. ③Extraordinary type: the cause of the disease is unknown, seen in the elderly, manifested by extremity bruising, hemolytic anemia and hematuria triad.
Symptoms
Prevalent in winter, can be relieved when the climate warms up. When symptoms occur, cold agglutinins often cause post-cold hemolysis. In rare cases, cold agglutinins can cause red blood cell agglutination in patients in cold environments, thus blocking blood vessels in cold areas, manifesting as cyanosis to grayish skin in the nose, mouth, face, ears, and fingers (toes). When the skin is cyanotic, there is local coldness, numbness and tingling, and touch, pain and temperature sensations are reduced or lost; when all fingers are cyanotic, warming of one finger can only make the cyanosis of that finger disappear. Hemoglobinuria and hemolytic anemia may occur in severe cases, but they are usually not serious.
Examination
1. Blood tests
There is mild anemia, white blood cells and platelets are not abnormal.
2. Condensation set test
Add the patient’s serum or plasma to normal human erythrocytes with the same blood type or type O. The erythrocytes can be seen to agglutinate when the temperature is below 20℃ in vitro, and the agglutination phenomenon disappears when the temperature rises to above 30℃.
Diagnosis
The diagnosis can be confirmed according to the clinical manifestations that the skin of the cold area of the patient will be cyanosis to grayish white in the cold environment, with local cold sensation, numbness and tingling sensation, and the decrease or disappearance of touch, pain and temperature sensation, and combined with a positive agglutination test.
Differential diagnosis
Differentiate from Raynaud’s phenomenon. The latter does not necessarily appear in the cold season, without pallor and redness; when all the fingers are cyanotic, warming one finger can make all the cyanotic fingers return to normal; negative condensation set test.
Treatment
Attention to warmth, active treatment of the primary disease, available vasodilators, such as dibazole, niacin and so on.
Prevention
Enhance warmth, wear hats, masks, gloves, etc. when going out in the cold season.