scarlet fever
Introduction
Scarlet fever profile Scarlet fever is an acute respiratory infection caused by group A hemolytic streptococcal infection. Its clinical features are fever, angina, diffuse red rash, and obvious desquamation after rash. A small number of patients suffer from illness. Abnormal reactions occur in the heart, kidney, joint damage. The incubation period is 2 to 12 days, most of which are 2 to 5 days. The onset is more rapid, with fever, angina and rash as the main clinical manifestations. basic knowledge The proportion of illness: 0.065% Susceptible people: good for children Mode of infection: droplet spread Complications: cellulitis, pneumonia, rheumatoid arthritis, myocarditis, endocarditis, pericarditis
Cause
Scarlet fever
Infectious lesions (30%):
Bacteria invade from the respiratory tract and adhere to the pharyngeal isthmus, causing inflammation, causing redness and swelling of the pharynx and tonsils, producing serous fibrinous exudate, sometimes ulceration, and bacteria from the local lymphatic space into nearby tissues, causing around the tonsils Abscess, sinusitis (nasosinusitis), otitis media, mastoiditis, cervical lymphadenitis, cellulitis, etc., a small number of critically ill patients may have sepsis and migratory suppuration lesions.
Toxic lesions (25%):
The rash of toxin produced by streptococcus enters the blood circulation through the pharyngeal blood vessels, causing symptoms of systemic poisoning, such as fever, dizziness, headache, loss of appetite, anorexia, etc.; rash toxin can cause blood vessel congestion, edema, epithelial cell hyperplasia, Leukocyte infiltration, the most obvious around the hair follicle, the formation of a typical scarlet fever-like rash, the final epidermal death and shedding; mucosa can also have a bit of bleeding; liver, spleen, lymph nodes and other degrees of congestion and fatty degeneration, and mononuclear cell infiltration; The myocardium may have turbid swelling and degeneration, and in severe cases, it may be necrotic; the kidney is interstitial; the central nervous system of the poisoned patient may show malnutrition changes.
Allergic lesions (25%):
Occurred in individual cases, more common in the second to third week of the disease, may group A streptococci and some tissues of infected people have similar antigens, resulting in an immune response, or due to deposition of antigen-antibody complexes in certain tissues Lesions, mainly cause allergic lesions of the heart, kidneys and joints.
Streptococcus is divided into 20 groups of A to V (no I, J) according to the polysaccharide antigens contained therein. The pathogen causing scarlet fever is group A hemolytic streptococcus, and the bacteria are spherical and arranged in chains. It has a diameter of 0.6-1.0m, is positive for Gram stain, has a capsule, does not move, does not form spores, is negative for catalase, grows well on blood medium, and produces complete (-type) hemolysis, group A streptococci can According to the difference of surface antigen M, it is divided into more than 90 serotypes. The pathogenicity of bacteria is related to the capsule of bacteria, M protein and the red rash toxin produced by some enzymes, and the lipoic acid and M protein of bacteria make bacteria adhere. In tissue, hyaluronic acid and M protein in the capsule make the bacteria have anti-phagocytosis; different types of Streptococcus group A can produce scarlet fever, which can cause scarlet fever, red rash toxin can cause fever and scarlet fever rash, red There are five serotypes of rash toxin, and there is no cross-immunization between different types; the streptokinase and hemolysin produced by bacteria are related to the pathogenesis, the anti-phagocytic ability of bacteria is strong, the level of streptolysin is high, and the level of cysteine protease is high. Low, related to heavy clinical performance, A Hemolytic streptococcus in sputum and pus may survive for several weeks, or 56 30min heating can generally disinfectant to kill.
Prevention
Scarlet fever prevention
At present, there is no automatic immunization preparation for this disease. The prevention focuses on controlling the spread of infection, isolating the child, and is quarantined after two negative negatives in the pharyngeal culture. Those who are close to the weak and immune function should be treated with the compound sulfamethoxazole or Penicillin injection, the carrier should receive 10 days of penicillin treatment.
(1) Management of infectious sources: patients and carriers are isolated for 6 to 7 days. Some people advocate treatment with penicillin for 2 days, so that about 95% of patients can be sterilized by pharyngeal test, and then they can be discharged, when they are children or recruit units. After the patient is found, it should be quarantined until the last patient has a disease of 1 week. If the pharyngeal test continues to be positive, the isolation period should be extended.
(B) cut off the route of transmission: during the epidemic, children should avoid public places, housing should pay attention to ventilation, for suspected scarlet fever, patients with angina and carriers, should be given isolation treatment.
(3) Protection of susceptible persons: For children's institutions, troops or other necessary groups, drug prevention may be used as appropriate, such as Penicillin G Benzathine, children 600-900,000 , adult 1.2 million , Protect for 30 days, or 1 gram of sulfadiazine per day or 0.5 grams of weekly iodine (Sulfadoxinum).
Complication
Scarlet fever complications Complications cellulitis pneumonia rheumatoid arthritis myocarditis endocarditis pericarditis
(1) Suppurative complications may be caused by the pathogen or other bacteria directly invading nearby tissues and organs, such as otitis media, mastoiditis, paranasal sinusitis, neck soft tissue inflammation, cellulitis, pneumonia, etc., due to early With antibacterial therapy, such complications are rare.
(B) toxic complications caused by various biological factors of bacteria, more common in the first week, such as toxic myocarditis, pericarditis, etc., the lesions are mostly transient, and the prognosis is good.
(3) Allergic complications are generally seen in the recovery period, and rheumatoid arthritis, myocarditis, endocarditis, pericarditis and acute glomerulonephritis may occur, and acute nephritis is generally mild and can be self-healing. Rarely turned chronic.
1. Rheumatism such as rheumatoid arthritis, both large and small joints can be involved, for migratory, may be red and swollen, joint cavity can accumulate serous exudate; some people can develop rheumatic myocarditis, endocarditis and pericarditis Valvular lesions may occur after the acute phase, and the onset is related to the immune response, but not related to the M protein antibody.
2. Acute glomerulonephritis occurs in association with group A streptococcus type 1,4,12,18 and 25, especially after type 12 infection is prone to nephritis, and is called "renitis type", disease Most of them last for about 1 month, most of them can be fully recovered, and a few can be prolonged into chronic nephritis.
3. Arthritis can occur 2 to 3 weeks after the onset of fever, mainly manifested as swelling and pain in large joints.
Symptom
Scarlet fever symptoms common symptoms sore throat high fever rose rash-like rash detoxification state rash body skin congestion hypothermia lymph node enlargement peeling itching
The incubation period is 2 to 12 days, most of which are 2 to 5 days. The onset is more rapid, with fever, angina and rash as the main clinical manifestations.
1. Fever 85%97% of patients have fever, mostly persistent, high or low, in recent years, fever is light and short, accompanied by headache, loss of appetite and general malaise, pulse growth, often exceeds body temperature The proportion of children, especially children, the level of heat and duration is consistent with the severity and change of the rash, generally fever for 1 week.
2. 98% of patients with angina have angina, the initial pharyngeal sensation is dry, followed by pain, aggravation when swallowing, about 80% of patients have tonsil enlargement, may have grayish white or yellowish white patchy purulent exudate Easy to erase.
3. The rash is usually seen before the appearance of the rash. There is an mucosal rash. It is manifested in the soft palate mucosal congestion, mild swelling, and there are millet granules or bleeding spots. The rash is one of the most important symptoms of scarlet fever, 100%. The patient has a rash. Most of the rash appears on the second disease day. It starts at the back of the ear, the bottom of the neck and the upper chest. Within a few hours, it extends to the chest, back, and upper limbs. It reaches the lower limbs around 24 hours. The typical rash is characterized by redness and swelling in the whole body. On the basis of the cap needle size, dense and evenly punctate congestive rash, the color fades, after the pressure, the red dot appears, and then merges into a piece of red, the vast majority of patients with rash is distributed throughout the body, rash Most of them are rashes, but you can also see the "chicken skin rash" protruding from the bulge, and occasionally the "miliary rash" with small pus, which is related to skin nutrition and health. In severe cases, hemorrhagic rash can be seen, and the skin often has itching. Sense, 30% to 60%, the patient in the skin folds such as the armpits, elbow fossa, groin, rash and often accompanied by subcutaneous hemorrhage forming a purple-red line, called "linear rash" or "Pap's line" , neck, body Dry, skin wrinkles and the rash on the inner side of the two thighs are most prominent, the distal extremities are rare, the face is congested and flushed, and there may be a small amount of rash, which appears pale under the nose and mouth, forming a so-called "peripheral pale circle", more rash than After 48h, the peak is reached, and then it disappears in the order of the rash. It can disappear completely in 2 to 4 days. The severe cases can last for 1 week or even longer. The rash in the mild cases is rare, only in the face, neck, chest, and hours. That is to say, the rash begins to peel after the rash subsides, and the order of the peeling site is the same as the order of the rash. The neck and the hind limbs are first, and the degree of peeling is proportional to the light and heavy of the rash. The light one is sputum-like, and the heavy one can be flaky. The neck and torso are often sputum-like, the limbs are especially palms, the soles of the feet are often large, sometimes even gloves, sock-like, facial rashes are less, but fine-grain-like peeling can also occur, and severe skin peeling can last for 3 ~ 5 weeks, the hair can also temporarily fall off, rash at the same time, the tongue can be white moss, nipple redness, prominent in the white moss, with the tip of the tongue and the edge is prominent, called "strawberry tongue", the third day white moss began to fall off The tongue surface is smooth and fleshy red, and there may be superficial rupture. The nipple is still bulging, which is called yangmei tongue. Some patients have enlarged neck and submandibular lymph nodes, and there is tenderness, but most of them are non-suppurative, and the clinical manifestations are quite different. The prognosis is also different, generally divided into the following five types.
(1) Ordinary type: More than 95% of patients in this epidemic belong to this type, clinical manifestations of fever, angina and typical rash, systemic poisoning symptoms, sub-sinus and cervical lymph nodes are non-suppurative inflammation, the course of disease is 1 week about.
(2) Light weight: The proportion of patients with near-young type is increased, showing low fever, mild sore throat, and rare rash. It is only found in the trunk, it dissipates quickly, the desquamation is not obvious, and the course is short, but allergic reactions can still occur. disease.
(3) sepsis type: rare, manifested as severe purulent inflammation of the pharynx, exudate, formation of purulent pseudomembrane, local mucosa can be necrotic and form ulcers, bacteria spread to nearby tissues, form suppurative otitis media, sinus Inflammation, mastoiditis and cervical lymphadenitis, and even soft neck inflammation of the neck can also cause sepsis and migratory suppurative lesions.
(4) Poisoning type: rare, mainly manifested in symptoms of poisoning, high fever, headache, severe vomiting, and even unconsciousness, may have toxic myocarditis, toxic hepatitis and septic shock, angina is not heavy, but rash Obviously, it may be hemorrhagic, but if shock occurs, the rash often becomes faintly visible and the mortality rate is high.
(5) Surgical or obstetric type: pathogens invade from the wound or the birth canal, so there is no angina, the rash first appears around the wound or the birth canal, and thus spread to the whole body, the symptoms of poisoning are lighter, and the prognosis is better.
Examine
Scarlet fever check
1. Blood: The total number of white blood cells (10 ~ 20) × 109 / L or higher, neutrophils can reach more than 0.75, poisonous particles can be seen in the cytoplasm.
2. Urine: Generally, there may be a small amount of protein, which is mostly transient. When nephritis occurs, the protein increases and red, white blood cells and casts appear.
3. Secretion culture and smear: pharyngeal secretions and wound secretions may be cultured with streptococcus. The smear of throat swabs can be detected by immunofluorescence.
4. Should do X-ray, ECG and other checks.
Diagnosis
Scarlet fever diagnosis
diagnosis
1. Suspected cases of fever, sore throat, red rash or congestive malignant rash on the skin.
2. Confirmed cases
(1) sudden fever, angina, strawberry tongue or bayberry tongue, pale mouth, skin folds at the skin fold red line (Pap's line).
(2) fever within 1-2 days of rash, diffuse skin congestion, flushing, during which the needle tip size scarlet rash, the pressure faded, 2 to 5 days later subsided.
(3) Defecation or peeling of the skin within 1 week of rash.
(4) The total number of white blood cells in the blood increased, and neutrophils increased.
(5) Throat swab or pus culture, and isolate group A -hemolytic streptococcus.
(6) Throat swab smear immunofluorescence method to detect group A -hemolytic streptococcus.
(7) The rash fading test was positive.
(8) The multivalent red rash toxin test was positive in the early stage of the disease and the recovery period was negative.
Clinical diagnosis: 4th and 1st or 2nd or 3rd of suspected cases plus confirmed cases.
Experimental diagnosis: 5th or 6th or 7th or 8th in the suspected case plus confirmed case.
Differential diagnosis
1. Scarlet fever pharyngitis and other angina syndrome before rash angina can not be distinguished from general acute pharyngitis, pharyngitis in patients with diphtheria is lighter than scarlet fever patients, pseudomembrane is tough and not easy to erase, and scarlet fever patients Pharyngeal purulent secretions are easily erased, but it should be noted that scarlet fever and diphtheria may be combined, and bacteriological examination should be performed carefully.
2. Identification of scarlet fever rash and other rash diseases
(1) Measles: There are obvious symptoms of upper respiratory tract catarrh. The rash appears on the 4th day of fever, varies in size, has different shapes, is dark red maculopapular rash, has normal skin between rashes, and has more facial rash than trunk. There are Coriolis spots, no strawberry tongue, and bayberry tongue.
(2) Rubella: On the first day of onset, the rash appears and begins to appear as measles. It increases rapidly and can be fused into a piece, similar to scarlet fever, but no diffuse skin flushing. The rash subsides after 3 days of onset, no desquamation, pharynx There is no inflammation in the department, and the lymph nodes are often swollen after the ear.
(3) drug rash: a history of useful drugs, rash can sometimes be diversified, both scarlet fever-like rash, but also urticaria-like rash, uneven distribution of rash, the order of rash is not like the scarlet fever from top to bottom, by the trunk To the limbs, no strawberry tongue and bayberry tongue, except for the drug rash caused by the patient's angina, generally no symptoms of pharyngeal inflammation, negative pathogen culture, rash after withdrawal.
(4) Other bacterial infections: Staphylococcus aureus, Group C Streptococcus, Streptococcus mutans also have strains capable of producing erythema toxin. The biological characteristics of the toxin are different from the erythema toxin of group A streptococci, but the scarlet fever sample is caused. There was no significant difference in rash. The identification was mainly based on bacterial culture. Streptococcus mutans had an outbreak in Jiangsu in the early 1990s. Some critically ill patients showed clinical manifestations similar to toxic scarlet fever. A group of toxins caused by different toxins.
