Cat scratch disease

Introduction to cat scratching Cat scratching is an infection caused by the body of Hanseatic. It is a pleomorphic gram-negative bacillus that can be observed by microscopy. When the patient is sick, lymphadenopathy and fever may occur. Cat scratching is widespread every year in the world, and its pathogens mainly infect humans through contact or catching and biting the skin of cats and other livestock. Typical clinical features are primary skin lesions, lymphadenopathy, and generally benign self-limiting. However, a small number of patients may have serious systemic damage, such as granulomatous hepatitis, hepatosplenomegaly, neuritis and meningoencephalitis. The entire course of disease is 1 to 4 months. basic knowledge The proportion of illness: 0.0003%-0.0005% Susceptible people: no special people Mode of infection: blood transmission Complications: osteomyelitis arthritis polymorphous erythema thrombocytopenic purpura

Cat scratching cause

(1) Causes of the disease

The pathogen of this disease was proved to be a polymorphic bacterium by Wear et al in 1983, and was negative for Gram stain. It was once called a caterpillar bacillus, and was named as Afipia felis by Brenner et al. (1991). In the future, it is impossible to prove that the pathogen of this disease is Effie, until Regenery et al. (1992) isolated two pathogens from the lymph nodes of typical cat scratch patients, which were identified as Rocalimae. One of the species, called R. henselae, was officially called Hansaiba after the Brenner et al. proposed to incorporate the genus Rokalima into the genus Barton in 1993. In the biological properties of Bartonella henselae, the morphology and culture, biochemical reaction and cell wall fatty acid composition of Hanseba are basically the same as those of the five-day thermobain, and the alanine-tRNA (tRNAAla) gene sequence is also the same. The citrate synthase gene (gltA) sequence of Hanseba is 65%, 63% and 66% identical to the rickettsia chinensis, the gram gram subtype and the E. coli gltA gene, respectively. There is obvious serum between the samba body and the five-day hot bar Cross-reactivity, one 48.5kD dominant antigen protein is the 5th heat, the total of the Han race, Wan Samba whole body.

(two) pathogenesis

After the pathogen enters the human body, it can be spread through the lymphatic system or blood source, causing damage to multiple organs of the body. The pathogenesis of the disease is still unclear, and may be related to the delayed allergic reaction of some components of the Hansaiba. When the human immune function is normal, the pathological reaction is granuloma-like and suppurative; when the body's immune function is low, the pathological reaction is vascular hyperplasia, early electron microscopy of infection, visible vascular wall and macrophage pleomorphic Gram-negative The pathogens are arranged in a single small body or in a chain or clustered, suggesting that the pathogen has affinity vascular endothelial cells. It has been reported that the pathogen can be found in cat red blood cells, suggesting affinity for red blood cells, through patients. Lymph node biopsy showed stellate necrotizing granuloma in the paracortical area and follicles in the lymph nodes of the lesion, and formed a multi-focal small abscess at the later stage, and then merged into a large abscess by suppuration. Epithelioid cells were seen at the edge of the abscess. Multinucleated giant cells, lymph nodes are thickened, and after several weeks to several months, fibroblasts proliferate in the diseased lymph nodes, gradually Scar formation is formed, and pathogens can be detected by using Warthin-Starry silver staining method in the diseased tissue within 1 to 4 weeks.

Cat scratch prevention

Do not raise or play with cats, dogs and other pets. Immediately after being scratched by cats and other animals, use iodine or mupirocin ointment (mupiroxin) for external disinfection, and observe local lymph nodes regularly. Patients do not need to be isolated. .

Cat scratching complications Complications osteomyelitis arthritis polymorphic erythema thrombocytopenic purpura

Complications include encephalopathy, hepatic granuloma, osteomyelitis, arthritis, polymorphous erythema, thrombocytopenic purpura and the like. Idiopathic thrombocytopenic purpura (ITP), also known as primary or immune thrombocytopenic purpura, is characterized by a significant reduction in peripheral platelets, developmental maturation of bone marrow megakaryocytes, and clinical manifestations of skin mucosa or visceral hemorrhage.

Cat scratching symptoms Common symptoms Parino eye-adenotrophy syndrome ecchymosis weight loss herpes diplopia appetite deficiency erythema nodules abscess abscess

The incubation period generally ranges from scratch to rash for 3 to 10 days, to local lymphadenopathy for about 2 weeks, and the whole course of cat scratching is more than 4 months, but there are also a few for 1 to 64 years, suggesting that chronic cat scratching The presence.

1. Primary skin damage

In typical cases, 64% to 96% of patients will have primary skin lesions about 3 to 10 days after scratching, such as maculopapular rash, nodular erythema, herpes, ecchymosis, urticaria, ring erythema and pustular rash. More common in the hands, feet, forearms, calves and face, usually lasts about 1 to 3 weeks, individual can heal after 1 to 2 months, the skin has a temporary pigmentation or crusting, but no scars, in 1 Hemangioma lesions occur gradually in ~2 months, and the small nodules of skin size of 0.5 to 2.0 cm can last for several months.

2. Local lymphadenopathy

About 10 to 15 days after the infection, the lymph nodes in the drainage area are swollen, more common in the head, cervical lymph nodes, followed by the infraorbital and inguinal lymph nodes, the ear, the back of the ear, the submandibular, the supraclavicular lymph nodes can also be affected, the size About 1 ~ 8cm, more pain, moderate hardness, 10% ~ 25% suppuration, often self-limiting, but for 2 months, individual cases until more than half a year to reduce swelling.

3. Whole body performance

50% of cases have fever, most of them are mild, often below 39 °C, about 9% of cases can have high fever, and patients often have fatigue, loss of appetite, vomiting, cough, headache, weight loss and sore throat. When the lymph nodes are purulent, the symptoms of systemic poisoning are obvious, and the symptoms disappear after wearing pus.

4. Central or peripheral nervous system syndrome

Symptoms of central nervous system involvement in about 2% of cases, manifested as encephalitis, meningitis, spinal radiculitis, optic nerve retinitis, polyneuritis or paraplevitis, mostly occur after lymph node enlargement 4-6 Week, cerebrospinal fluid lymphocytosis, protein increased, EEG abnormalities in most cases, complete recovery takes several months, those with underlying immunodeficiency, the condition is often heavier.

5. Other performance

In recent years, some syndromes have been reported to be associated with cat scratching, which is called clinical manifestation of atypical cat scratching, and is more common in children.

(1) Parinaud's oculoglandular syndrome (POGS): In cat scratching, a small number of children (about 6%) have this syndrome, which is caused by ocular granuloma or pre-auricular lymphadenopathy. Swelling with conjunctivitis, Carithers (1978) reported 14 cases of atypical cat scratch disease with this syndrome, and emphasized the characteristics of granulomatous lesions, 2 to 3 mm, or even greater than 1 cm at the orbital membrane. The red to yellow nodules, the appearance of ocular symptoms may be caused by the direct or indirect entry of the Hanseba through the eyelids. This syndrome is a self-limiting infection with a good prognosis. The Palino eye-adenogly syndrome may also be Tuberculosis, rabbit fever, inguinal lymphogranuloma and syphilis have been caused, but recently, serine specific DNA has been determined by serological detection and PCR techniques, which has been confirmed to be the most common form of atypical cat scratching.

(2) Leber stellate retinopathy: In 1916 Leber reported a unique retinitis disease called idiopathic Leber's stellate retinopathy (special hair) Sexual Leber's stellate optic neuritis, idiopathic Leber's stellate streak disease), the cause was not clear at that time, until 1970-1977, it was considered to be related to cat scratch disease, the disease is common in children and youth Mostly asymmetry, painless visual loss, swollen optic disc, stellate plaque formation, and finally spontaneous dissolution, complete recovery of vision within 1 to 3 months.

Cat scratching inspection

Blood routine

At the early stage of the disease, the total number of white blood cells decreased, the lymph nodes became mildly elevated, the neutrophils increased, and the erythrocyte sedimentation rate accelerated.

2. Pathogen culture and isolation

From the patient's blood, lymph node pus and primary skin lesions, Hanseba can be isolated and cultured, the diagnosis is affirmative, but most of the pathogens are cell wall-deficient, and the culture conditions are higher, only in blood or chocolate medium. It can be grown for 6 weeks in a 35 ° C carbon dioxide incubator, and then the morphological Gram-negative bacilli can be seen by the Warthin-Starry silver dip staining method, which cannot be used as an early diagnosis method and is limited in clinical application.

3. Immunological examination

(1) Skin test: The cat scratching antigen has not yet been commercialized, so it is more valuable to use the antigen from the lymph node puncture liquid for sterilization. The skin test method: take the antigen 0.1ml forearm volar intradermal injection. At 48h, the induration with diameter 5mm was positive, surrounded by 30~40mm edema flush, the blush generally existed for 48h, the induration lasted for 5-6 days or 4 weeks, and the skin test was delayed type hypersensitivity, which was more sensitive and specific. The false positive is about 5%. Repeated 2 times at 4 weeks is still negative for the diagnosis of cat scratching. The positive skin test after infection can be maintained for more than 10 years.

(2) Indirect immunofluorescent antibody test (IFA): Determination of Hanseba-specific antibodies in serum of patients with fluorescein-labeled antigen, the titer of which is 1:64 is positive, and the positive rate is reported to be 88%. The control group was only 3%, and the serum titer increased by more than 4 times in the early course of the disease and 4 to 6 weeks. It is also meaningful for diagnosis. This test is a simple, rapid, sensitive and specific diagnosis of the disease. Methods.

(3) Enzyme-linked immunosorbent assay: detection of anti-Henseba total body IgM antibody, sensitivity, specificity, clinical diagnostic value, ELISA ~ IgG antibody sensitivity is low, can not be used as a laboratory diagnostic criteria.

The above IFA and ELISA-IgM antibodies are used as serological diagnostic criteria for cat scratching. The two are rarely different in serotype and cross-react with the five-day heat barton. If the type is required, the bacteria should be cultured to further clarify. .

4. Molecular biology testing

In recent years, PCR, nested PCR or PCR in situ hybridization has been used to detect the DNA of Hanseba from lymph node biopsy specimens and pus, with a positive rate of 96%, but this method of specificity and sensitivity is high. High condition requirements, difficult to be used as clinical routine examination, PCR detection of Hansai and Five-day Reptile DNA, CAT1, CAT2 pair of specific primers, the nucleotide sequence (5'3') is GATTCAATTGGTTTGAA (G And A) GAGGCT and TCACAATCACCAGG (A and G) CGTATTC, a 414 bp fragment product can be amplified.

5. Histopathological examination

For biopsy tissue for Warthin-Starry and Brown-Hopps tissue staining or tissue electron microscopy, it is helpful for diagnosis, but tissue staining cannot distinguish between different bacterial types or other pathogens of Bartonella.

Early electron microscopy showed that there were pleomorphic Gram-negative pathogens in the blood vessel wall and macrophages, which were arranged in a single small body or in a chain or clustered together, suggesting that the pathogen has affinity vascular endothelial cells. The pathogen can be found in the red blood cells of cats, suggesting that the red blood cells also have affinity. Through the lymph node biopsy of the patient, a stellate necrotizing granuloma appears in the paracortical area and the follicles in the lymph nodes of the lesion, and the multifocal small part is formed in the later stage. Abscess, then merged into a large abscess through suppuration, epithelioid cells can be seen at the edge of the abscess, occasionally multinucleated giant cells, lymph node capsule thickening, after weeks to months, fibroblasts proliferate in the diseased lymph nodes, gradually forming scars, Pathogens can be detected by using Warthin-Starry silver staining method in diseased tissues within 1 to 4 weeks.

Cat scratch diagnosis

diagnosis

1. Epidemiological history: There are close contact with cats, dogs, monkeys and hares, and there is a history of being caught, licked or bitten.

2. The cat scratching antigen skin test is positive.

3. Exclude lymphadenopathy caused by other causes.

4. Lymph node tissue biopsy conforms to the typical pathological features of cat scratching, namely necrotizing granuloma and small abscess. It is stained with Warthin-Starry silver stain and found to have Hansaiba body. When all the above three indicators are available, The clinical diagnosis was cat scratching, and the serological test (IFA and ELISA-IgM method) was used to confirm the diagnosis.

Differential diagnosis

The disease should be differentiated from lymphoma, tuberculosis, rabbit fever, sexually transmitted lymphogranuloma and AIDS. Lymphocytes have undergone malignant transformation, which is called lymphoma. According to the "World Health Organization Lymphatic System Tumor Pathology Classification Standard", there are nearly 70 pathological types of lymphoma, which can be roughly divided into Hodgkin's lymphoma and non-Hodgkin. There are two major types of lymphoma.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.