BMS 301 CNS Pathology Lecture 1 PDF

BMS 301 Faculty of medicine Fall 2024 Galala University gu.ed u. eg CNS Pathology Module 301 Lecture 1 Dr. Mohammed Abdellah (MD).  CNS Infections...

BMS 301 Faculty of medicine Fall 2024 Galala University gu.ed u. eg CNS Pathology Module 301 Lecture 1 Dr. Mohammed Abdellah (MD).  CNS Infections & tumors (1) By the end of lecture; you should be able to: - Identify the routes of CNS infections. - Differentiate between the acute pyogenic, acute lymphocytic (aseptic/viral) meningitis and chronic meningitis. -Differentiate between meningitis and encephalitis. -Recognize the possible complications of meningitis. -Appreciate the role of HIV as predisposing factor for opportunistic infections. -Recognize important features of CNS tumors (consequences of location/patterns of growth/patterns of spread). ⮚Outline common CNS tumors and identify broad clinical presentation ⮚Describe Gliomas / Meningioma ⮚Outline common childhood tumors ⮚Identify broad lines of management of brain tumors ⮚Identify secondary tumors/lymphoma ⮚Differentiate between CNS tumors and other SOL (e.g. brain abscess & Tuberculoma)  INFECTIONS A large number of pathogens comprising various kinds of bacteria, fungi, viruses, rickettsiae and parasites can cause infections of the nervous system. The micro-organisms may gain entry into the nervous system by one of the following routes Routes of CNS Infection: 1. Via blood stream: arterial (is the most common). Less often, the spread may occur by venous route. 2. Direct implantation: following skull fractures or through defects in the bony and meningeal coverings. 3. Local extension: from contiguous focus (otitis media and frontal or mastoid sinusitis). 4. Along nerve: certain viruses such as herpes simplex, herpes zoster and rabies spread along cranial and peripheral nerves and ascend to the CNS.  INFECTIONS In general, resultant lesions are in the form of either diffuse inflammation of the meninges (meningitis) and of brain parenchyma (encephalitis), or combination of both (meningoencephalitis). In addition, other inflammatory lesions of CNS include: brain abscess, epidural abscess, subdural empyema, septic thromboembolism of dural sinuses and encephalomyelitis. Acute Pyogenic Meningitis (Bacterial Meningitis) Systemic signs of infection. Meningeal irritation (neck stiffness). Neurologic impairment (headache, photophobia, irritability, clouding of consciousness). Acute Pyogenic Meningitis Acute Pyogenic Meningitis ORGANISM PEAK AGE INCIDENC GRAM STAIN Escherichia coli Neonates Gram negative rods Hemophilus influenzae Infants and Children Gram negative coccobacilli Neisseria meningitidis Adolescents and Young adults Gram negative diplococci Streptococcus pneumoniae Older adults or Children Gram positive cocci in chains. =Staphylococcus is common among injection drug busers.  Brain Abscess 1- Usually hematogenous spread of bacterial infection. 2- Direct penetrating trauma. 3- Extension from adjacent infection in sinuses or otitis media. Brain Abscess  Chronic Meningitis - Several pathogens (T.B. and some spirochetes). - Associated with chronic meningitis - and/or encephalitis. Tuberculous Meningitis - Generalized signs and symptoms of headache, malaise, mental confusion, and vomiting. - Infection with T.B. also may result in a tuberculoma - - Chronic tuberculous meningitis is a cause of arachnoid fibrosis, which may cause hydrocephalus tuberculoma Aseptic (Viral) Meningitis Meningeal irritation, fever, and alterations in consciousness of relatively acute onset. Less fulminant than in pyogenic meningitis. Typically is selflimiting.  Viral Encephalitis Parenchymal infection of the brain that is almost invariably associated with meningeal inflammation (and therefore is better termed meningoencephalitis).  HIV encephalitis Chronic inflammatory reaction with microglial nodules and associated reactive gliosis. In some cases, there is also multifocal or diffuse areas of myelin pallor with associated axonal swellings and gliosis. HIV is present in CD4+ mononuclear and multinucleate macrophages and microglia. HIV encephalitis  HIV complications: 1. HIV-encephalopathy (AIDS-dementia complex) 2. Opportunistic infections: Toxoplasmosis , Cryptococcal meningitis, Progressive multifocal leucoencephalopathy, Neurosyphilis , Tuberculous meningitis 3. Neoplasms : Primary CNS lymphoma, Kaposi’s sarcoma. 4. Peripheral neuropathies 5. Myelopathy (Spinal cord disease).  CNS TUMORS General considerations: No premalignant or in situ stages comparable to those of carcinomas. Benign intracranial tumors can result in devastating clinical consequences due to compression phenomena. The anatomic site of the neoplasm can influence outcome independent of histologic classification due to local effects. Rarely spread outside of the CNS.  CNS TUMORS CNS tumors according to location: 1- INTRA AXIAL (Arising from brain parenchyma) Cerebral Hemisphere Cerebellar Hemisphere Ventricles Brain stem 2-EXTRA AXIAL (Arising from tissue covering brain) Bone tumor Dural based Cranial nerves CPA / Sellar and supra sellar CNS TUMORS brain tumors: Brain tumors  Gliomas Gliomas are intra-axial tumors Are classified as: ⮚Astrocytomas ⮚Oligodendrogliomas ⮚Ependymoma  Astrocytomas = Intra axial The most common primary brain tumors in adults. WHO grades I, II, III or IV. Glioblastoma Maultiforme WHO grade IV. Pilocytic astrocytoma WHO grade I. Astrocytomas Astrocytomas