Brain

Brain

1. Normal

   • Protection
     • Scalp
       • 1- Skin
       • 2- Connective tissue
       • 3- Epicranial Aponeurosis
       • 4- Loose areolar tissue
       • 5- Pericranium
       • Arterial supply
         • External carotid artery
           • Superficial temporal artery
           • Posterior auricular artery
           • Occipital artery
         • Internal carotid artery
           • Supratrochlear artery
           • Supraorbital artery
       • Venous Drainage
         • Accompany the arteries and have similar names
         • Freely anastomose with each other and are connected to
           • Intracranial dural sinuses through several emissary veins
           • Diploic veins
       • Nerve Supply
         • 5 in front of auricle
           • 1 Motor
             • Temporal branch of facial nerve
           • 4 sensory
             • Supratrochlear nerve
             • Supraorbital nerve
             • Zygomatico-temporal nerve
             • Auriculo-temporal nerve
         • 5 behind auricle
           • 1 Motor
             • Posterior auricular branch of facial nerve
           • 4 sensory
             • Great auricular nerve
             • Lesser occipital nerve
             • Greater occipital nerve
             • 3rd occipital nerve
     • Meninges
       • Dura mater
         • Outer layer forms the endocranium
         • Inner layer is folded to form the dural folds
           • Falx cerebri
           • Tentorium cerebelli
       • Arachnoid
       • Pia
     • Blood Brain Barrier
       • Separates the circulating blood from the CSF
       • The endothelial cells in tight junction create the boundary between the two fluids
       • The projections of the Astrocytes, called the astrocytic feet or the glia limitans, surround the endothelial cells, providing the needed support

2. Abnormal

   • Meningitis
     • Clinical Picture
       • Fever
         • Pathophysiology
           • First stage
             • Production of cytokines and their release
               • Pyretic cytokines
                 • IL-1/ IL-6/ IL-8/ Macrophage inflammatory protein 1b/ Interferon gamma
               • Antipyretic cytokines
                 • IL-10/ AVP/ a-MSH/ TNF-a/ Glucocorticoids
           • Second stage
             • Cytokines involve on thermoregulatory center
         • Differential diagnosis
           • Infectious agent
             • Viruses/ Bacteria/ Parasites/ Fungi
           • Neoplasm
           • Autoimmune disorders
             • Rheumatoid arthritis / SLE
           • Metabolic disorders
             • Gout/ Porphyria
           • Others
             • Trauma/ Drugs / Vaccines
       • General signs of infection Hemorrhagic rash
       • Symptoms & Signs of meningeal irritation
         • Neck Stiffness
           • Differential diagnosis
             • Infectious causes
               • Abscess/ Lymphadenitis/ Encephalitis/ Meningitis/ Discitis/ Herpes zoster/ Osteitis/ Tetanus
             • Neurological causes
               • Cerebral palsy/ Epidural hematoma/ Intracranial hemorrhage/ Post-lumber puncture/ Vertebral anomaly
             • Arthritis
             • Deconditioning or muscles overuse
             • Torticollis
               • Spasm of sternocleidomastoid muscle or hemorrhage
             • Tumor
         • Headache/ Photophobia/ Irritability/ Altered consciousness/ Nausea&Vomiting/ Seizures
         • Kernig’s sign & Brudzinski’s sign
     • Epidemiology of Neisseria Meningitides
       • Sub-Saharan Africa characterized by seasonal epidemics in the dry season with incidence rate of 10 to 100 cases per 100,000
       • In the meningitis belt, 350 million people at least are at risk of getting meningitis in the annual epidemics
     • Pathophysiology
       • Bacteria
         • Penetrates BBB; endotoxin and inflammatory mediators initiate a CSF inflammatory response
           • Causing leakage of protein and fluid out of the cerebral vasculature
             • Causing cerebral edema and cerebral vascular thrombosis
               • Edema and increased intracranial pressure
                 • Reduction in cerebral perfusion and cerebral infarction
                   • Brain death
     • Management
       • Empirical Therapy
       • Antimicrobial Agents
     • Chemoprophylaxis
       • Vaccine – pre-exposure prophylaxis
       • Rifampin and ciprofloxacin - ideally within 24 hours after the case is identified
     • Prevention
       • Vaccines against three types of bacteria
         • Neisseria meningitidis (meningococcus)/ Streptococcus pneumoniae (pneumococcus)/ Haemophilus influenzae type b (Hib)
     • investigations
       • Cerebrospinal fluid
     • Complications
       • Hydrocephalus/ Hearing Loss/ Seizures/ Thrombophlebitis/ Septicemia (Waterhouse-Friderichsen Syndrome)/ Death

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