Acute hematogenous osteomyelitis

Acute hematogenous osteomyelitis, also called acute osteomyelitis, is inflammation caused by pyogenic bacteria invading the connective tissue of the marrow through the bloodstream in most cases. A few spread from nearby soft-tissue infection or follow open fracture; without timely treatment, bone structure is destroyed and disability results, and spread of infection can even be life-threatening. Some cases become chronic with a long course; since it is common in children, it may affect nutrition and growth.

Common Symptoms

Periosteal reaction; Lan Rui; meningeal irritation signs; bone destruction; anorexia; severe pain; delirium; restlessness; severe pain; soft tissue swelling

Causes

It mostly occurs in children and adolescents, starting at the long-bone metaphysis where clusters of bacteria settle and multiply; once a focus forms, the abscess is surrounded by bone with poor drainage, so severe toxemia is common, and the abscess then spreads in different directions according to local resistance. (1) Etiology. Pathogens are usually hemolytic Staphylococcus aureus; recently more virulent hemolytic Staphylococcus albus, occasionally Salmonella, pneumococci or other pyogens, most resistant to penicillin and streptomycin; common primary foci are pustules, gingival abscess and upper respiratory infection. (2) Pathogenesis. Bacterial virulence is the external factor, while general condition and local bone resistance are internal factors; the metaphysis has many terminal arterioles, rich slow circulation favoring bacterial growth; bacteria such as staphylococci often cluster and embolize small arteries, occluding vessels and causing local necrosis favorable to infection; clinical sprains and contusions are often indirect causes. Within 48h of onset, bacterial toxins damage metaphyseal capillaries, forming pus that via Haversian systems and Volkmann canals enters subperiosteally and strips the periosteum, causing bone destruction and necrosis together with a reparative response (hyperostosis); early phase is mainly destruction and necrosis; the inner cortex is supplied by metaphyseal blood, and once impaired, bone necroses and granulation separates it as sequestra; periosteal reaction forms new bone called involucrum enclosing infected and necrotic bone, later with defects forming cloacae and sinuses draining pus; late phase is mainly hyperostosis. Once an intraosseous focus forms, poor drainage causes severe toxemia, and as the abscess enlarges, infection spreads along paths of least resistance. 1. Spread of abscess. (1) Toward the long-bone end: the epiphyseal plate resists infection, so pus rarely enters the joint and mostly spreads into the medullary cavity; increased pressure spreads pus along central canals to the subperiosteum forming a subperiosteal abscess. (2) Pus breaks through metaphyseal compact bone into the subperiosteum; with higher pressure it breaks through the periosteum into soft tissue or invades the medullary cavity along Haversian canals. (3) Into the joint causing pyogenic arthritis; the pediatric epiphyseal plate is a natural barrier, but the adult plate has little resistance; if the metaphysis is intra-articular (e.g. femoral neck in the hip capsule), pus can break through into the joint. 2. Bone nutrition: the part near the medullary cavity is supplied by nutrient vessels, and the cortical part near the periosteum by a subperiosteal vascular network; when the periosteum is lifted, the cortex loses periosteal blood supply, impairing bone circulation and causing necrosis; pus entering the marrow and central canals causes thrombosed nutrient vessels, blocking supply and causing necrosis; the necrotic area depends on ischemia, and the whole diaphysis may necrose. Periosteal stripping stimulates deep osteoblasts to form abundant new bone around sequestra as involucrum supporting the diseased bone, and pus drains through it; small sequestra are absorbed or drained, but large ones cannot, leaving a persistent cavity and chronic osteomyelitis.

Treatment

Medication, supportive treatment

Prevention

Professional guidance. It is mostly hematogenous, so actively prevent and treat sepsis and various skin and mucosal and upper respiratory infections; the focus is nursing, pre- and postoperative: I. Preoperative nursing. 1. Acute osteomyelitis starts with high fever, chills, anorexia and irritability; pain, swelling and limited movement are local signs; care as a critical patient, using physical and drug cooling and alcohol sponge baths for fever. 2. Do not neglect general supportive care: antipyresis, fluids, intake-output to maintain water-electrolyte balance, fresh blood for anemia, high-protein diet and multivitamins. 3. Clean the skin preoperatively; avoid skin injury when preparing. 4. Diet: fast 8 hours and withhold water 4 hours before surgery. 5. Cooperate with preoperative tests: urge parents to provide urine and stool samples, escort the child for X-rays and special tests, and do skin tests. 6. Psychological nursing: show sympathy and responsibility, care for the child, build rapport, talk with parents to explain the disease and care, building trust and confidence to aid recovery. II. Postoperative nursing. 1. Observe vital signs: children are mostly under general anesthesia; on return, supine without a pillow, head to one side to prevent aspiration, keep the airway open, check vital signs every 30 minutes until awake. 2. Give digestible nutritious food; since bed rest causes constipation, give high-fiber food, more water, fruits and vegetables. 3. Fix the limb with a plaster splint to reduce pain and prevent fracture; if bony prominences are painful, it indicates pressure and needs prompt handling; keep the bed tidy and dry, massage pressure areas to prevent bedsores, and observe distal circulation, skin color, temperature, sensation, pain and swelling. 4. Two silicone tubes in the medullary cavity provide continuous irrigation and drainage; irrigate with normal saline plus gentamicin; drip 24-hour irrigant evenly, record inflow and outflow, and if there is a large difference, flush a blocked output tube; observe drainage volume, odor and color, change the sterile drainage bottle daily, and check the wound dressing; extubation signs: ① clear drainage; ② swelling subsided; ③ normal temperature, according to general condition. 5. Functional exercise: early muscle contraction-relaxation to prevent atrophy and adhesion; later extend to major joints for comprehensive rehabilitation.

Recommended Department

It is recommended to visit the orthopedic surgery department; before the visit you may first book an appointment and connect with experts through this platform.

Warm reminder: The above information is provided for health education reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek care at a regular hospital in time.