Serum sickness

Serum sickness is a systemic immunopathological reaction to the introduction of parenteral foreign protein, animal serum. It can manifest itself both with repeated and primary introduction of foreign serum. Serum sickness occurs in 5-10% of patients who were administered foreign serum.

A foreign protein that enters the child’s body circulates in the blood, causing the synthesis of antibodies with the subsequent formation of immune complexes, their deposition on tissues, damaging the latter and releasing biologically active substances.

[ 1 ], [ 2 ]

Causes of serum sickness

Serum sickness may develop with repeated or primary administration of foreign serum (against tetanus, diphtheria, rabies, snake bites, botulism or gas gangrene). Serum sickness syndrome is sometimes observed after the administration of y-globulin, antilymphocyte serum, or insect bites.

[ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ]

Pathogenesis

In the mechanism of development of serum sickness, the main role is played by the long-term circulation of foreign protein in the blood, formation of secondary antigens and then immune complexes (with the obligatory participation of complement), deposition of circulating immune complexes on tissues with their damage (type III hypersensitivity reactions, allergic reactions developing according to the Arthus phenomenon). The incubation period of the disease is 1-2 weeks. In other cases, when the characteristic clinical picture develops faster (in the first 1-5 days after application of serum), the main role in pathogenesis is played by skin-sensitizing antibodies (reagins - IgE) and the allergic reaction proceeds according to the anaphylactic type.

Symptoms of serum sickness

Symptoms of serum sickness are characterized by the appearance of pain and swelling at the injection site of the serum on the 7-10th day after its administration. The patient develops fever, enlarged regional lymph nodes, sometimes joint damage (arthralgia, edema), urticarial papular or erythematous itchy rash appears on the skin; conjunctivitis. Symptoms from the cardiovascular system are noted: tachycardia, muffled tones, dilation of the borders of the heart. Blood pressure decreases. In a young child, damage to the gastrointestinal tract is possible: vomiting appears, stool becomes frequent with mucus, "intestinal colic" occurs. Proteinuria and microhematuria may appear in the urine. Sometimes, with a severe course of serum sickness, laryngeal edema with the development of stenotic breathing, asphyxia, hemorrhagic syndrome may appear. In mild forms, the disappearance of clinical symptoms may occur within 2-5 days from the onset of serum sickness; in severe forms, within 2-3 weeks.

The prognostic factors for a full recovery are: severe damage to the heart, kidneys, nervous system, development of hemorrhagic syndrome, laryngeal edema.

Treatment of serum sickness

In mild cases, antihistamines are prescribed, 10% calcium chloride solution or 10% calcium gluconate solution orally, ascorbic acid, rutin are prescribed. In severe cases, prednisolone is administered at a rate of 1 mg / kg of body weight per day in a short course. In case of severe itching - local rubdowns with 5% menthol alcohol solution. In case of articular syndrome, intomation, brufen, voltaren are prescribed.

Prevention of serum sickness

When administering animal serums - diphtheria antitoxin, tetanus antitoxin, botulinum antitoxin, rabies serum. The Committee on Childhood Infections of the American Academy of Pediatrics recommends the following sequence of measures:

• make a scratch, prick or puncture on the inner surface of the forearm and drop one drop of serum diluted 1:100 in isotonic sodium chloride solution on top; a reaction with erythema with a diameter of more than 3 mm is considered positive (“read” after 15-20 minutes);
• in case of a negative reaction, children without a burdened allergic history are injected intradermally with 0.02 ml of serum at a dilution of 1:100;
• children with atopic diathesis are first given a 1:1000 dilution of serum and, if the reaction is negative, after 20 minutes a 1:100 dilution is given and they wait 30 minutes;
• If the reaction is negative, the entire dose of the therapeutic serum is administered intramuscularly.

If intravenous administration is necessary (for example, in the case of toxic diphtheria), 0.5 ml of serum diluted in 10 ml of isotonic sodium chloride solution is administered first, and only after 30 minutes the remaining serum in a 1:20 dilution (injection rate 1 ml/min). When administering serums, it is always necessary to have an anti-shock kit of medications.

Even an intradermal test, not to mention subcutaneous and intravenous administration, can be complicated by anaphylactic shock. However, it is believed that the intravenous route of administration of serums is safer, since it is better controlled. Negative tests do not guarantee the absence of anaphylactic shock when the entire dose is administered, which necessitates the presence of an anti-shock kit of medications when administering serums.

Prognosis for serum sickness

The prognosis is usually good unless there is kidney damage.