Central Nervous System
Also written as CNS.
Multiple Sclerosis (MS): MS is an autoimmune disease in which the immune system mistakenly attacks the protective covering of nerve fibers in the central nervous system.
What our notes say
- Multiple Sclerosis (MS): MS is an autoimmune disease in which the immune system mistakenly attacks the protective covering of nerve fibers in the central nervous system. (9.COVID-19ptt)
- Potential causes include genetic/chromosomal conditions, congenital brain abnormalities, prenatal exposures or infections, prematurity or perinatal complications, severe early malnutrition, central nervous system infections, traumatic brain injury and some metabolic disorders. (Neurodevelopmental Disorders I: Autism Spectrum Disorder and Intellectual Disabi)
- Central nervous system: Meninges (meningitis), brain parenchyma (tuberculoma). (Tuberculosis: pulmonary and extrapulmonary)
- Absolute contraindications to fibrinolytics include previous hemorrhagic stroke, ischemic stroke within six months, known central nervous system neoplasm or vascular malformation, recent major trauma/surgery, active internal bleeding, or suspected aortic dissection. (Acute coronary syndrome and myocardial infarction)
- Localization symptoms: Cough, hemoptysis, dyspnea (respiratory); dysuria, flank pain (urinary); photophobia, neck stiffness, confusion (central nervous system); abdominal pain, diarrhea (gastrointestinal); joint pains or rashes (rheumatologic/arboviral). (Approach to fever)
- These indicate central nervous system (CNS) infections like cryptococcal meningitis, cerebral toxoplasmosis, or tuberculoma. (HIV and opportunistic infections)
Study material on Central Nervous System
- Devendra K. Gupta, Krishna M. Goel - Hutchison’s Paediatrics. chdhe-Jaypee Brothers (2012)
- Harrisons Pulmonary and Critical Care Medicine
- Kaplan Pediatrics pdf-notes 201506051322 - flattened (2)
- BABY NELSON PEADS
- Davidson's Essentials of Medicine - 2nd
- CNS Malignancies
- Other CNS Infections
- Other CNS Infections
- Meningitis
- Harrisons Cardiovascular Medicine 2nd Edition 2
- Medical Physiology IV (CNS) — MCQ Bank
- Weekly Year 1: Physiology Exam - August 7, 2026 (Section A: MCQs)
- Virology 2 — MCQ Bank
Practice questions on Central Nervous System
What is the primary barrier between the central nervous system (CNS) and the peripheral nervous system (PNS)?
- The meninges
- The vertebral column
- The dura mater
- The blood-brain barrier
Answer: B. The CNS and PNS are functionally and anatomically distinct divisions of the nervous system. While protective layers like meninges and the blood-brain barrier are crucial for CNS protection, there isn't a single 'barrier' separating the CNS from the PNS in the way the question implies. Instead, it's a matter of organizational and anatomical demarcation.
Most excitatory neurotransmission in the central nervous system is mediated by
- GABA
- Glycine
- Glutamate
- Serotonin
- Acetylcholine
Answer: C. Glutamate is the principal excitatory neurotransmitter in the CNS. GABA and glycine are the major inhibitory amino-acid neurotransmitters.
How does tetanus toxin reach inhibitory interneurons in the central nervous system?
- Via lymphatic spread
- Via retrograde axonal transport
- Via direct arterial spread
- Via cranial nerve hematogenous spread
- Via the gastrointestinal tract
Answer: B. Tetanus toxin enters peripheral motor nerve terminals and undergoes retrograde axonal transport to the central nervous system, where it blocks release of inhibitory neurotransmitters.
Regarding viral infection of the central nervous system (CNS), one of the statements below is false
- Meningitis may occur together with encephalitis
- Enteroviruses are one of the commonest causes of CNS infections in childhood
- HSV encephalitis is a post-infectious encephalomyelitis
- Measles encephalitis is a post-infectious encephalomyelitis
Answer: C. HSV encephalitis is a DIRECT viral encephalitis — the virus actively replicates within brain parenchyma. It is NOT post-infectious. Measles encephalitis (ADEM) IS a post-infectious autoimmune encephalomyelitis.
A 60-year-old with established CLL complains of headaches and blurred vision. Which diagnostic procedure is indicated to assess for central nervous system involvement?
- Magnetic resonance imaging of the brain
- Lumbar puncture with cerebrospinal fluid cytology
- Positron emission tomography
- Computed tomography of the chest
Answer: B. CSF cytology directly detects leukaemic cell infiltration of the central nervous system.