nocardiosis
Introduction
Introduction to Nocardiosis Nocardiosis is an acute, chronic, suppurative (even granulomatous) disease caused by Nocardia. Nocardia is an actinomycete. basic knowledge The proportion of illness: the incidence rate is about 0.003%-0.005% Susceptible people: no special people Mode of infection: respiratory transmission Complications: endocarditis myocarditis pericarditis
Cause
The cause of nocardiosis
Bacterial infection (75%):
The pathogens are more common with N. sphaeroides and S. cerevisiae. The latter is highly pathogenic and can cause outbreaks. The common feature of this genus is that the hyphae are slender, with a diameter of 0.3-0.2 m, and many curved like tree roots. Generally, it grows to more than 10 hours and begins to form a diaphragm, which is broken into rods of different lengths, braided filaments, Gram-positive, cell wall type IX, sugar type A, and contains LCN-A lipids and slaves. The acid content of the cardinic acid in the DNA is 60-70 mol%. There are more than one hundred species in the genus, which are widely distributed in the soil, and most of them are aerobic bacteria.
Environmental factors (25%):
Pathogens often enter the skin through the trauma or through the respiratory tract, the digestive tract enters the human body, and then is confined to an organ or tissue, or spread to the brain, kidneys or other organs through the blood circulation.
Prevention
Nocardiosis prevention
Prevent the occurrence of trauma, and find that the wound should be disinfected by rubbing purple syrup or iodine in time. Pay attention to personal hygiene, wash hands frequently, and prevent infection. Early reasonable treatment can avoid the occurrence of dissemination, and the synergistic effect of combined synergy is better.
Complication
Nocardiosis complications Complications, endocarditis, myocarditis, pericarditis
Concurrent endocarditis, myocarditis, pericarditis.
Symptom
Nocardial symptoms common symptoms convulsions, weight loss, night sweats, dry cough, chest pain, fatigue, unconsciousness, visual impairment, dizziness, edema
Nocardia invades the skin and internal organs, causing local and systemic infections, causing a variety of clinical manifestations.
Pulmonary nocardiosis
About 75% of cases invade the lungs, with acute or subacute onset, which is characterized by lobular or lobar pneumonia. It tends to be chronic, and can be similar to tuberculosis, coughing, starting with dry cough, innocent, and then Septic sputum, can also carry blood in the sputum; if there is a cavity, there may be a lot of hemoptysis, often accompanied by fever, night sweats, chest pain, weight loss, general malaise, body temperature between 38 ~ 40 ° C, involving the pleura can occur Pleural thickening, pleural effusion or empyema, sinus can penetrate the chest wall, can also extend to the entire abdominal cavity, which in turn causes blood source to spread, chest X-ray performance is diverse, no specificity, such as lung segment or lung lobe Invasive lesions, thick-walled cavities, necrotizing pneumonia, lobar pneumonia, single or multiple lung abscesses, solitary or multiple nodules, pleural effusion, bronchopleural fistula, etc., can also be expressed as intrapulmonary miliary Shadows, but less common.
2. Brain nocardiosis
About 1/3 of the cases have central nervous system involvement, mostly migrated from the lung lesions, a few can also be primary, invading the meninges to cause meningitis, invading the brain parenchyma to form multiple abscesses, can also be merged into a large Abscess, meningeal irritation or brain occupying lesions, may have headache, dizziness, nausea, vomiting, irregular fever, fatigue, convulsions, numbness, hemiplegia, neck stiffness, visual impairment, confusion, optic disc edema, congestion, Peripheral blood leukocytes increased and other performance.
3. Disseminated nocardiosis
It is often spread from the lung lesions to the whole body. The kidney is the most common site after the brain. At the same time, endocarditis, myocarditis and pericarditis, liver, spleen, adrenal gland, gastrointestinal, lymph nodes and ribs, femur can occur. Vertebrae, pelvis and joints can also be affected, while pancreas, thyroid, eye, ear, spinal cord, pituitary, and bladder involvement are rare.
4. Skin nocardiosis
It is often caused by the invasion of pathogenic bacteria caused by plant damage to the skin, and it can also be spread from the lung lesions. The subcutaneous nodule group which can be arranged in a chain appears in the arm, which is characterized by sporotrichosis-like nocardiosis. It is characterized by abscess and chronic fistula or sickle-like lesions similar to skin tuberculosis. Some patients may have extensive vesicular rash, and some patients may develop gangrenous skin nocardiosis, which begins with painful subcutaneous nodules, superficial skin. The flushing red quickly spreads and collapses. The edge of the ulcer is irregular and falls inward. The surface of the ulcer has a sticky yellow-white pus.
Examine
Nocardiosis check
Pathogen inspection:
1. Direct microscopic examination of sputum, pus, cerebrospinal fluid, tissue block, etc., first digested, and then centrifuged to prepare tablets for direct microscopic examination, Gram stain can be seen slender, curved with branched hyphae.
2. The culture material is inoculated in a medium containing no antibiotics, cultured under aerobic conditions, and identified according to colony characteristics and physiological characteristics.
Chest X-ray findings are diverse and non-specific, such as invasive lesions of the lung or lobe, thick-walled cavities, necrotizing pneumonia, lobar pneumonia, single or multiple lung abscesses, solitary or multiple nodules.
Diagnosis
Diagnosis and identification of nocardiosis
The diagnosis of this disease mainly relies on laboratory tests, and the pathogens can be confirmed. Therefore, cases with clinical manifestations of suspected disease should be examined in multiple ways in time.
The lung nocardiosis should be differentiated from various types of tuberculosis, pulmonary mycosis, bacterial abscess and tumor. Skin nocardiosis needs to be differentiated from sporotrichosis, skin tuberculosis and actinomycete. Brain nocardiosis should be differentiated from brain-occupying lesions such as brain tumors and bacterial brain abscesses. The differential diagnosis of disseminated nocardiosis is more complicated. The key is to be alert to this disease.
