Pine Caterpillar Disease Osteoarthritis

　　1. Etiology

　　The etiology is unknown, but the onset is closely related to the contact with Dendrolimus pini, with a high incidence in June and July and October and November each year, consistent with the life history of the adult generation of Dendrolimus pini. The onset site is mostly the exposed parts of the body, and all cases are mainly local symptoms, so it is generally believed that the pathogenic cause is the human body contacting the toxic bristles of the Dendrolimus pini thoracic segment and being contaminated by the toxins in the toxic gland cells.

　　2. Pathogenesis

　　The pathogenesis is not very clear. There are currently three hypotheses: ① Poisoning, the bristles of the Dendrolimus pini penetrate the human skin, the toxins enter the blood circulation, causing toxicemia and peripheral tissue reaction; ② Allergy; ③ Infection. The pathological materials of this disease are few, and there is no definite conclusion. According to the observation of the pathological materials after a small amount of local lesion resection, the synovial membrane has varying degrees of thickening, vascular hyperplasia, obvious swelling of the endothelial cells, and abundant infiltration of lymphocytes, plasma cells, and a small amount of eosinophils, with active fibroblast hyperplasia and focal osteoid formation. The bone ends have limited bone destruction and hyperplasia, and the joints have varying degrees of fibrous rigidity and bony rigidity, while the joint fluid smear and necrotic tissue culture did not find bacteria. The pathological changes are similar to those of rheumatoid arthritis, suggesting that the pathogenesis of this disease is related to allergy.

　　The etiology of this disease is not very clear. It is generally believed that the pathogenic cause is the human body contacting the toxic bristles of the Dendrolimus pini thoracic segment and being contaminated by the toxins in the toxic gland cells. It belongs to the combined action of allergic reaction and toxic reaction on the synovial membrane, which may lead to joint dysfunction, joint deformity, and rigidity in the late stage, causing lameness and hunchback. As well as local swelling caused by bone hypertrophy and deformation.

　　Characterized by local swelling and pain, occasionally with leukocytosis and rapid blood sedimentation, generally without systemic symptoms.

　　1. Acute stage:Within one month after onset, within a few hours or several days after contacting the Dendrolimus pini, local dermatitis symptoms appear, with swelling of the surrounding soft tissue of the joint, skin itching, swelling and pain, luster or small blisters may appear, generally recover within a few days, in severe cases, the surrounding soft tissue of the joint is significantly swollen, the skin is purple-red, accompanied by severe pricking-like jumping pain, especially at night, sometimes there is a small amount of effusion in the joint.

　　2. Subacute stage:Within 1 to 6 months after onset, the swelling of the surrounding soft tissue of the joint decreases, but gradually becomes hard, with bone and joint lesions occurring after the local symptoms are relieved, and joint dysfunction may occur.

　　3. Chronic stage:After half a year of onset, it often lasts for 2 to 3 years or more, with the surrounding soft tissue of the joint still swollen, but mainly hard, with pain relief, but may occur intermittently.

　　Prevention should avoid direct skin contact with Dendrolimus and its contaminants; treatment should be immediate cleaning with soap and water, or ash water, or applying dilute ammonia water, taking antiallergic drugs, and keeping the affected limb at rest.

　　It is necessary to publicize relevant knowledge to the masses so that they understand that the disease is a local manifestation of a systemic disease caused by direct or indirect contact with the living, dead bodies, or scales of Dendrolimus. The toxins in the spines and toxin gland cells of Dendrolimus can cause allergic immune inflammatory reactions upon contact with the skin or entering the human body, causing pain to the patients and even lifelong disability. Therefore, it is advocated that the people in high-incidence areas wear long-sleeved clothes or long pants when working or going out to avoid exposing their skin to Dendrolimus. If contact is made, it should be cleaned immediately with soap and water, or applied with ammonia water. Not only can it prevent the onset of the disease, but it can also neutralize the toxins and alleviate pain.

　　X-ray films can be used for the examination of this disease, and the X-ray film manifestations are as follows.

　　One, acute stage:Soft tissue swelling around the joint is an early change, soft tissue layers are blurred, and in severe cases, reticular dense shadows may appear, joint cysts are large, and density increases.

　　Two, subacute stage:Soft tissue swelling around the joint, large joint cysts, local density increase, osteoporosis, initially seen only at the bone ends, which can later develop into generalized osteoporosis, bone destruction, with certain characteristics.

　　1. Bone end bone destruction:It occurs on one or both sides of the bone ends, manifested as single or multiple small circular worm-eaten destruction areas with clear edges, or superficial bone defects, more common in multiple cases, without reactive bone hyperplasia around, the joint surface is intact, and wedge-shaped bone defects can appear at the top of the tubular diaphysis epiphysis, below the epiphysis.

　　2. Joint destruction:Subchondral joint surfaces can show blurred destruction areas, if the epiphysis has not fused, the destruction area can occur internally, the joint cartilage is destroyed, and the joint space narrows.

　　3. Destruction of bone ends and joints:Both the bone ends and the joint are destroyed, which may be accompanied by joint dislocation or subluxation.

　　4. Destruction of bone prominences where tendons attach:It is manifested as local soft tissue swelling, accompanied by marginal single or multiple small circular perforating bone destruction areas with sharp edges, commonly found above and below the calcaneal tuberosity, above and below the patella, and at the tuberosity of the tibia.

　　The periosteal hyperplasia is layered or scalloped, common in phalanges, and there are small pieces, nodular, or strip-like calcification in the soft tissue near the adjacent bone destruction area.

　　Three, chronic stage

　　1. The local soft tissue swelling of the joint persists.

　　2. The area of bone destruction stops developing and slowly repairs, the surrounding cancellous bone becomes明显 hardening, showing marginal dense small translucent shadows, which are characteristic of the chronic stage. The bone cortex becomes irregularly thickened, and the trabeculae become coarse and disordered.

　　Four, in the late stage:The ends of the bones are enlarged and deformed, with nodular protrusions, most prominent at the patella and calcaneal tuberosities. The joint space narrows, and there are joint deviation, subluxation, and joint stiffness, which are generally fibrous stiffness.

　　1. What foods are good for caterpillar disease bone and joint disease patients:Drink plenty of water. Eat a balanced diet, rich in nutrition, and consume semi-liquid foods high in protein and vitamins.

　　2. What foods should be avoided for caterpillar disease bone and joint disease:Avoid spicy and cold foods. Do not eat spicy and stimulating foods to avoid recurrence of the disease, such as seafood, chicken, dog meat, etc. At the same time, do not ban spicy foods.

　　I. Treatment

　　Prevention should avoid direct contact with the caterpillar and its contaminants; after contact with the caterpillar, the affected area should be immediately washed with soap and water or ash water, or applied with dilute ammonia water, antiallergic drugs should be taken, and the affected limb should be kept at rest. In the later stage, there are obvious osteoarthritis changes, and surgical treatment should be performed regardless of whether there are sinus tracts locally. The operation must remove all synovium to reduce the chance of recurrence; if the articular cartilage surface is severely damaged and cannot be repaired, joint fusion surgery should be performed.

　　1. Nursing Issues:Fever, weakness; joint pain, deformity; lack of knowledge of health care.

　　2. Nursing Goals:Reduce body temperature and discomfort; relieve pain and suffering; keep the joints in a functional position to prevent deformity; do a good job of preventive publicity.

　　3. Nursing Measures

　　(1) Take appropriate rest; those with high fever, weakness, or severe pain should rest in bed to reduce consumption and alleviate pain. Physical cooling should be used when necessary, keeping clothing and bedding dry and comfortable, avoiding cold, and drinking plenty of water.

　　(2) Eat a balanced diet, rich in nutrition, and consume semi-liquid foods high in protein and vitamins, avoiding spicy and cold foods.

　　(3) Be patient with the patient, especially when the pain occurs, more attention should be given to care and concern to enhance their confidence in overcoming the disease. For those whose severe pain affects sleep, analgesics can be administered according to circumstances.

　　(4) Place the joint of the affected limb in a functional position to prevent deformity.

　　(5) Those with fistulas or sinus tracts should pay attention to keep the area clean, change dressings in a timely manner, and prevent mixed infections.

　　II. Prognosis

　　The prognosis of this disease is good, and it can be cured with proper treatment in most cases.