Tuberculoma of the brain is a tumor—like granulomatous formation caused by the penetration of tuberculosis pathogens into the cerebral tissues. Clinically manifested by cerebral and focal neurological symptoms characteristic of intracerebral neoplasms. The diagnostic program includes neurological examination, ophthalmological examinations, phthisiatric consultation, cerebrospinal fluid analysis, X-ray diagnostics, cerebral MRI. The main method of treatment is surgical removal of tuberculoma on the background of anti-tuberculosis therapy with subsequent rehabilitation.
ICD 10
A17.1 A17.8
General information
Tuberculoma of the brain (TB) is a separate form of extrapulmonary tuberculosis with focal intracerebral lesion. In the literature on clinical neurology, there is a synonymous name for the pathology — cerebral tuberculous granuloma. According to various data, tuberculosis accounts for 2.1-3.4% of all brain tumors. The disease is characteristic of childhood and adolescence, more often observed in boys. In 90% of cases, tuberculosis in the lungs or lungs is detected in patients, in 18% – various forms of extrapulmonary tuberculosis lesions (skin tuberculosis, intestines, kidneys). In 50% of patients, the infectious process is disseminated.
Causes
Pathogens of infection (tuberculous mycobacteria) penetrate into brain tissues by hematogenic, lymphogenic pathways mainly in the dissemination phase. The primary foci of infection are usually the lungs and lymph nodes, much less often — foci in the intestines, organs of the genitourinary system, bones, skin. In 8% of cases, the primary tuberculous focus cannot be detected. Factors predisposing to the dissemination of mycobacteria are immaturity of the blood-brain barrier, reduced immunity (due to primary or secondary immunodeficiency, diabetes mellitus, hormone therapy), endocrine restructuring.
Pathogenesis
Intracerebral penetration of mycobacteria is accompanied by the formation of a focus of chronic granulomatous inflammation surrounded by a capsule. Solitary solitary tuberculoma is more often observed, 23% of patients have multiple foci. In 80% of cases, the structures of the posterior cranial fossa are affected, usually the hemispheres of the cerebellum. As the tuberculoma grows, it squeezes the IV ventricle, blocks the pathways of the cerebrospinal fluid outflow, which causes occlusive hydrocephalus. With supratentorial localization in the hemispheres, tuberculosis acts as a trigger for epileptogenic impulses, leading to the appearance of epileptic paroxysms.
The processes of differentiation and calcification cause clinical remission of the disease, a new activation of granulomatous inflammation is accompanied by an aggravation of symptoms. Morphologically, tuberculoma is an encapsulated formation reaching a diameter of 2-3 cm. The contents of the focus are represented by granulomatous tissue containing epithelioid, lymphoid, giant cells, altered cells of the cerebral parenchyma. At a certain stage of development, a zone of caseous necrosis is formed in the center of education. Sometimes the contents of the granuloma have a liquid consistency.
Classification
The widespread use of neuroimaging methods, the constant search for lifetime diagnostic methods and tomographic features of tuberculosis have led to the identification of several types of tuberculous granulomas, taking into account their morphological structure. The classification is used mainly in MR diagnostics, includes three main types of tuberculosis:
- Non—caseous – has homogeneous granulomatous contents of dense consistency. On MRI in T1 mode, it is visualized as a hypointensive focus, in T2 mode — as a hyperintensive focus. When contrasting, there is a uniform contrast enhancement of the formation. A similar tomographic picture is typical for the initial stages of TB.
- Caseous — consists of a centrally located focus of curd necrosis surrounded by dense granulomatous tissue. During tomography, it gives a hypo- and isointensive signal in both modes. Contrast is accompanied by a ring-shaped image enhancement.
- Liquid — there is a liquid in the center of the formation. Liquid tuberculoma does not differ tomographically from a brain abscess. Hypo-, isointensive in T1, T2 modes, contrasts as a narrow ring. It is characterized by high signal intensity on diffusely weighted images.
Symptoms
Tuberculous granuloma can have a latent, latent course without a significant increase in size. In such cases, petrified tuberculoma is detected only during autopsy. Clinically manifesting TB are characterized by symptoms typical of cerebral tumors. Gradually, cerebral and focal symptoms appear and progress, periods of deterioration alternate in waves with periods of some improvement. In some patients, the onset of tumor-like manifestations is preceded by an acute episode with an increase in body temperature, pronounced general infectious, cerebral and meningeal symptoms. In the future, subfebrility and mild meningeal phenomena persist, focal deficiency manifests itself after 1-3 months.
The growth of the formation is accompanied by intracranial hypertension, causing headache, nausea, vomiting, congestive optic nerve discs. If the granuloma is localized in the posterior cranial fossa near the cerebrospinal fluid pathways, the outflow of the cerebrospinal fluid becomes difficult, hydrocephalus increases. When located in the hemispheres, epileptic seizures are observed, often – paroxysms of Jackson’s epilepsy, generalized seizures. Tuberculosis of frontal localization is manifested by a disorder of the psyche, behavior, intellectual abilities. When the parietal lobe is affected, paresis, hypesthesia, apraxia, aphasia are noted. The location of the granuloma in the left temporal lobe leads to acoustic-gnostic aphasia. When subcortical ganglia are affected, hyperkinesis is detected.
Cerebellar tuberculoma is characterized by symptoms of cerebellar ataxia: unsteadiness of gait, intentional tremor, nystagmus, movement coordination disorder, muscle hypotension in the homolateral extremities. Discoordination of the articulatory apparatus causes a speech disorder — a chanted pronunciation of words devoid of intonation (cerebellar dysarthria). With an increase in the formation of the cerebellum, compression of the medulla oblongata, the roots of the cranial nerves coming out of it with the development of their dysfunction is possible.
Complications
Progressive focal deficiency invalidates the patient. Occlusive hydrocephalus is accompanied by cerebrospinal hypertension crises with a sharp increase in intracranial pressure, intense headache, repeated vomiting, inability to eat. A particular danger is the compression of the brain stem with vital centers located in it, which develops due to hydrocephalus. Epileptic status can become a complication of epileptic paroxysms. In some cases, there is a rupture of TB with infection of the membranes of the brain, the occurrence of tuberculous meningitis. Without timely treatment, the latter leads to a fatal outcome.
Diagnostics
Diagnosis of the disease is difficult, since the clinical and tomographic pictures are similar to a cerebral tumor. Cases of tuberculoma of the brain have been described in patients who do not have symptoms of specific inflammation and indications of previously suffered tuberculosis. In most patients, tuberculosis is detected during surgical treatment for brain neoplasms. The list of necessary diagnostic measures includes:
- Collecting anamnesis. What matters is the transferred or current tuberculosis, the presence of tuberculosis in people who are in constant contact with the patient. Attention should be paid to long-term subfebrility and other symptoms of chronic infectious disease according to anamnesis.
- Consultation of a neurologist. The study of the neurological status confirms the presence of cerebral symptoms indicating an increase in intracranial pressure, mild meningeal syndrome. The nature of focal deficiency suggests localization of the process.
- Consultation of an ophthalmologist. A decrease in visual acuity is detected. When the formation is located in the chiasm and optical tracts, the perimetry diagnoses the loss or limitation of visual fields. During ophthalmoscopy, the swelling of the optical nerve discs is determined.
- Consultation of a phthisiologist. It is carried out in the presence of chest radiography and the results of a tuberculin test. Radiography makes it possible to identify lung damage, primary tuberculosis complex. The turn of the tuberculin sample indicates the presence of an active tuberculosis process. In a number of patients, the sample is within the normal range, sometimes it is negative.
- Blood test. A pattern of moderate inflammatory changes is characteristic. There is a small leukocytosis, accelerated ESR, a possible shift of the leukocyte formula to the left. From specific diagnostic tests, enzyme immunoassays are used to confirm infection: QuantiFERON-TB and T-SPOT.TB.
- Examination of the cerebrospinal fluid. There is an increased concentration of protein, moderate pleocytosis. Sowing liquor on nutrient media rarely gives the growth of mycobacteria, since the process is clearly delimited by a capsule. Determination of the causative agent in the cerebrospinal fluid is more typical for generalized types of tuberculous lesions of the central nervous system – meningitis, meningoencephalitis.
- Skull x-ray. The images show signs of a prolonged increase in intracranial pressure: finger depressions on the bones of the arch, osteoporosis of the Turkish saddle, divergence of cranial sutures. In the presence of calcification of TB, it is visualized on radiographs.
- MRI of the brain. A thorough comprehensive study using T1/T2 modes, diffusion-weighted images, and MR spectroscopy is recommended. In favor of tuberculoma, there is a small perifocal edema, the presence of a shell, ring-shaped contrast.
Differential diagnosis of tuberculoma of the brain is carried out with primary and metastatic neoplasia of cerebral localization. Often, verification of the diagnosis is possible only based on the results of intraoperative histological examination. It is necessary to exclude other infectious brain lesions that have a similar tomographic picture: cysticercosis, toxoplasmosis, bacterial abscess, cryptococcosis.
Treatment
Neurosurgical removal of tuberculoma of the brain is associated with intraoperative contamination of surrounding tissues with mycobacteria, the subsequent spread of infection through the cerebrospinal tract with the development of tuberculous meningitis. Because of this, before the advent of anti-tuberculosis drugs, surgical removal of TB was fatal in 82% of cases. Patients with petrified formations and convexital granulomas, leading to limited meningitis, survived. With the advent of anti-tuberculosis chemotherapy drugs, the results of surgical treatment have significantly improved. In modern neurosurgical practice, the treatment of TB includes four main stages:
- Anti-tuberculosis therapy. It is carried out comprehensively and for a long time by combining 2-3 pharmaceuticals. Streptomycin, rifampicin, isoniazid are used. In the postoperative period, endolumbal administration of streptomycin is performed.
- Neurosurgical removal. The operation is performed by neurosurgeons, access depends on the localization, requires bone-plastic trepanation of the skull. The formation is exfoliated together with the capsule within healthy tissues.
- Dehydration therapy. To reduce hydrocephalus, prevent cerebral edema in the postoperative period, the administration of magnesium sulfate, the appointment of diuretics (furosemide, mannitol, diacarb) is indicated. In severe cases, glucocorticosteroids are recommended.
- Rehabilitation. It is aimed at restoring lost nervous functions. The medicinal component includes neurotropic, neurometabolic pharmaceuticals that improve nutrition and the functioning of nervous tissue. Kinesiotherapy, limb massage, and physical therapy are widely used among non-drug methods. Speech restoration is carried out by practicing with a speech therapist.
Prognosis and prevention
Timely removal of tuberculoma of the brain against the background of active etiotropic therapy ensures recovery of 75% of patients. Cases of multiple cerebral tuberculosis, rupture of education with the development of acute tuberculous meningitis, combined lesions of the central nervous system, severe combined lesions of internal organs have a serious prognosis. Primary prevention of TB consists in the identification, full-fledged treatment and follow-up of tuberculosis patients, carrying out mass anti-tuberculosis vaccination of children. Secondary preventive measures involve regular monitoring of postoperative patients, control of cerebrospinal fluid 2 weeks after the end of anti-tuberculosis therapy and 6 months after surgery.