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Presentation on theme: "CENTRAL NERVOUS SYSTEM PATHOLOGY"— Presentation transcript:



3 DEMYLEINATING DISEASES Multiple sclerosis (M.S.)_
Definition: Chronic relapsing-remitting (complete or partial recovery then another attack) disorder of an autoimmune origin Characterized by episodes of demylination in the brain, optic nerve and spinal cord resulting in progressive neurological deficits

4 Pathology: Acute lesion:
Grossly: peri-ventricular well-circumscribed plaques Microscopically: Loss of myelin Phagocytosis of myelin by macrophages Preservation of axons Chronic inflammatory cells Chronic lesion: No inflammation Axon remyleination But remyleination is defective

5 Multiple sclerosis

6 Pathophysiology: During the acute stage: nerve conduction is blocked
Chronic disease: there is slow nerve conduction Recurrent attacks → progressive neurological deficit

7 According to the site of nerve demylenation:
Clinically: According to the site of nerve demylenation: Vertigo (brain stem involvement) Loss of sensation and movement in a limb (spinal nerves involvement) Neuropsychiatry disorders

8 Degenerative diseases:
Parkinson’s disease Huntington’s disease Alzheimer disease

9 Parkinson disease Definition: Grossly:
Loss of pigmented neurons in substansia nigra Grossly: Pallor of substansia nigra in pons


11 Clinically: Slowing of all voluntary movements
Tremors at rest that disappear on movement Expressionless face Rigidity in limbs and trunk and inability to initiate voluntary movements Associated with increased incidence of dementia and depression

12 Huntington’s disease (HD)
Definition: Autosomal dominant disorder characterized by atrophy of caudate nucleus with secondary ventricular dilatation

13 Huntington disease (HD)
Atrophy of caudate nucleus Huntington disease (HD)

14 Microscopically: Clinically: Loss of small neurons in caudate nucleus
Age: years Chorea: sudden, unexpected and purposeless contractions of the proximal muscles Changes in the personality with tendency to suicide and dementia

15 3- Alzheimer disease: Risk factors: Pathologically: Aging
Significant head trauma Pathologically: Accumulation of abnormal proteins intra and extra cellular Senile plaques: core of amyloid surrounded by dendretic processes, microglial cells and astrocytes

16 Alzheimer disease

17 Clinically: Gradual onset, usually begins in the seventh or the eighth decades Progressive memory impairment Alteration in mood and behavior Progressive disorientation Aphasia (loss of language) Within 5-10 years become mute and bedridden

18 CNS infectious disease are classified as:
CNS INFECTIONS CNS infectious disease are classified as: Bacterial infection Viral infection Fungal infection Toxoplasmosis infection Prion infection

19 Bacterial infection of CNS

20 Acute purulent meningitis
Definition: Purulent leptomeningeal inflammation due to bacteria Causative bacteria: Neonate: streptococci group-B and E-coli Infants and children: Heamophilus infleuenzae Young adults: Neisseria meningitides Elderly: Streptoccocus pneumoniae

21 Acute purlent meningitis

22 Pathological features:
Clinical features: Diffuse cerebral edema with increased risk of brain herniation Headache, fever, nuchal rigidity, cloudy sensorium, coma and death Hydrocephalus and cranial nerve impairment Pathological features: Neutrophilic infiltration of the meninges and extending to the cortex

23 Cerebral abscess Hematogenous spread or direct spread from contiguous focci Predisopsing conditions: Acute bacterial endocarditis and chronic pulmonary abscess Mastoiditis, paranasal sinusitis, acute otitis, open fractures and previous neurosurgery Clinically: Signs of increased intracranial pressure (headache, vomiting and papilledema) Focal neurological deficits


25 Viral infection of CNS Poliomyelitis: Etiology & pathogenesis:
It is a viral infection of the nervous system by poliovirus, an entero-virus transmitted by fecal-oral route. The virus enters the body through the intestine and multiplies in lymphoid tissues of oropharynx and intestine (incubation period) then invades the blood stream then it reach the brain and spinal cord. Poliomyelitis is now rare because of routine immunization during childhood

26 Poliomyelitis

27 c- Human Immunodeficiency Virus (HIV):
Cerebral involvement with HIV leads to AIDS dementia Histologically : Microglial nodules Diagnostic giant cells Spinal nerve involvement leads to vacuolar myelopathy

28 Primary manifestations of AIDS
HIV encephalitis: multinucleated giant cells, gliosis and inflammation

29 Toxoplasmosis Frequent in AIDS patient Clinically:
Cerebral abscess with central necrosis and chronic inflammation


31 Prion disease of brain Creutzfedt-Jacob disease:
CNS disease caused by prion protein. The infectious agent has been called a prion. A prion is defined as "small proteinaceous infectious particles". Prion diseases are often called spongiform encephalopathies because of the post mortem appearance of the brain with large vacuoles in the cortex and cerebellum.

32 Pathological features:
Vacuolation of the gray matter in the cortex Neuronal loss Kuru plaques: these are deposites of amyloid Clinically: These cases rapidly progress to dementia and memory loss Involuntary movments Death within 6-12 months

33 Spongiform encephalopathies cause the brain tissue to become spongy and
riddled with microscopic holes.


35 CLASSIFICATION Tumors of the CNS can be classified according to five fundamental origins: The neuroectoderm (principally gliomas) Mesenchymal structures (notably meningiomas and schwannomas, and primary brain lymphoma) Tissues and cells that have been ectopically displaced intracranially during embryonic development Retained embryonal structures Metastases

36 Astrocytomas The most common type of glioma
Accounts for 15-20% of primary brain tumors in the adult The highly malignant form is called Glioblastoma Multiforme Grossly: The tumor has poorly defined margins and is infiltrative. Most commonly found in cerebral hemispheres Microscopically: Uniform appearing nuclei occur in fibrillary background or matrix


38 Oligodendroglioma Slowly growing tumour
Seizures and convulsions are the prominent 1st complaint

39 Ependymoma Occurs most commonly in the 4th ventricle and in that location may lead to obstructive hydrocephalus. Ependymoma in 4th ventricle

40 Meningiomas “Tumor of the meninges"
II- Mesenchymal Origin Meningiomas “Tumor of the meninges" Accounts for 20% of primary adult brain tumors Occurs in later decades of life Extremely slow growing and benign Common presenting symptoms include headache, seizures and dementia

41 Metastatic Tumors Account for 50% of all brain tumors in adults
In order of propensity to metastasize: lung, breast, melanoma, kidney, thyroid Carcinomas of the GI tract, bladder, prostate, ovaries and uterus rarely go to brain Grossly, tend to be round with well-defined borders. Necrosis and hemorrhage are frequent. Usually multiple

Schwannoma Neurofibroma Neurofibromatosis Malignant schwannoma

Definition: A bengin tumor arising from Schwann (neurilemma) cells of the peripheral (cranial or spinal) nerves. Gross: A firm grayish capsulated mass at one side of the nerve. The 8th cranial, acoustic nerve is one of the famous sites of schwannoma.

44 NEUROFIBROMA Pathology:
Appears as rubbery expansion of the affected nerve, not demarcated from nerve Neurofibroma has a significant risk of malignant transformation

45 NEUROFIBROMATOSIS (Von Recklinghausen's disease of nerves)
It is a familial disease (autosomal dominant inheritance) of two types: Type I (NFI): It is characterized by Multiple neurofibromatosis, mainly cutaneous Acoustic schwannomas Café au lait spots (hyperpigmented skin macules) Eye lesions: Optic nerve gliomas Pigmented nodules of iris Type II (NFII): It resembles type I without eye affection


47 MALIGNANT SCHWANNOMA Also called malignant peripheral nerve sheath tumor (MPNST) It is a poorly differentiated spindle cell sarcoma of peripheral nerve. The tumor may arise de novo or from malignant transformation of a neurofibroma or neurofibromatosis. Occus in adults in the larger nerves of the trunk or proximal limbs as an uncapsulated fusiform enlargement of a nerve.

48 PERPHERAL NEURITIS Definition: Causes:
This is inflammation and degeneration of peripheral nerves Causes: Diabetes mellitus is one of the most common causes of peripheral neuritis Chronic alcoholism Chronic lead poisoning Beriberi

49 Leprosy Toxemia as diphtheria Acute post-infective polyneuritis; it follows infective diseases as measles and influenza or after vaccination and is thought to be allergic nature Ischemia as in cases of polyarthritis nodosa Traumatic as in cases of disc prolapse

50 Signs and symptoms Deficits which include numbness, tremors and gait abnormality, loss of function, tiredness and heaviness. Symptoms include tingling, pain, itching and pins and needles. Pain can become intense enough to require use of opioid (narcotic) drugs (i.e., morphine).

51 Skin can become very hypersensitive
Skin can become very hypersensitive. People with this degree of sensitivity cannot have a bed-sheet touch their feet or wear socks or shoes. There is also pain in the muscles (myalgia), cramps.

52 Examples of neuritis

53 Leprosy Leprosy is a chronic slowly progressive, destructive process involving peripheral nerves, skin and mucous membranes. Caused by Mycobacterium leprae. Leprosy is transmitted from person to person usually as a result of years of intimate contact.

54 Vitamin B3 deficiency (niacin, nicotinic acid):
Pellagra: Clinical niacin deficiency, characterized by dermatitis, diarrhea and dementia, and also glossitis and degeneration of posterior and lateral columns of the spinal cord.


56 Vitamin B6 deficiency (pyridoxine):
Deficiency is related to the development of neuropathy.

57 Folic acid deficiency (Vitamin P):
Megaloblastic (macrocytic) anemia Hypersegmented neutrophils Associated with neural tube defects in utero

58 Vitamin B12 deficiency (cobalamin, cyanocobalamin):
Vitamin B12 is present in all foods of animal origin. Deficiency causes ("pernicious anemia"). Macrocytic anemia, demyelinized posterior columns ("subacute combined degeneration of the cord"), later brain dysfunction.


60 Guillian–Barré syndrome
An acute polyneuropathy, a disorder affecting the peripheral nervous system Ascending paralysis, weakness beginning in the feet and hands and migrating towards the trunk. It can cause life-threatening complications, in particular if the breathing muscles are affected

61 The disease is usually triggered by an infection.
The diagnosis is usually made by nerve conduction studies. With treatment the majority will recover completely. Guillain–Barré syndrome is rare, at 1–2 cases per 100,000 people annually, but is the most common cause of acute non-trauma-related paralysis in the world. Can be confused clinically with poliomyelitis



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