Pathology Flashcards
Definition of epilepsy?
Sudden synchronous discharge of cerebral neurons causing signs & symptoms apparent to patient or observer.
Definition of Seizure?
Abnormal electrical discharge of brain that causes involuntary & unpredictable, repetitive, paroxysmal neural activity.
Causes of epilepsy?
- primary generalised epilepsy (PGE)
- hippocampus sclerosis
- vascular disorders
- brain tumours or lesions
- neuro degenerative disorders
- alcohol withdrawal
- metabolic abnormalities
What is PGE?
Primary generalised epilepsy. Polygenic together with a complex inheritance. Abnormalities of ion channels influences neuronal firing, abnormality of neurotransmitter release. Hence, epilepsy occurs
What is hippocampus sclerosis?
Major cause of epilepsy. The sclerosis is visible on MRI, and a common cause of refractory epilepsy. It’s the main cause of temporal lobe epilepsy and localization related epilepsy.
Classification of epilepsy?
Generalized - consists of absence(petit mal), tonic-clonic(grand mal), myoclonic, tonic & atonic.
Partial - consists of simple partial and complex partial, also partial with secondary generalization.
Explain about petit mal?
It causes a 3 Hz spike-and-wave. Loss of awareness occurs in kes tuhan. 10 seconds, then patient returns to normal consciousness. Patinets dos bot realize they’re having an attack.
What is grand mal?
It’s another name for the tonic-clonic epilepsy. Consists of four phase.
- prodrome (aura prior to secondary generalized seizure)
- tonic (stiffening of the muscles)
- clonic (synchronous jerking of the limbs. Patient may utter an initial cry and fall. Eyes remained open and tongue is usually bitten)
- postictal (period of flaccid unresponsiveness, followed by gradual awareness return with confusion & drowsiness. Headache is common)
Elaborate types of skull fracture
Displaced skull fracture - fracture in which bone is displaced into the cranial cavity by a distance greater than the thickness of the bone itself
Basal skull fracture - fracture of the base of the skull, involving temporal bone, occipital bone, sphenoid bone & ethmoid bone.
Diastatic fracture - fracture which crosses suture
Types of head injury
- Skull fracture
- Traumatic parenchymal injuries
- Vascular injury
List down types of traumatic parenchymal injury
- Contusion
- Penetration of the brain
- Diffuse axonal injury
- Concussion
Define contusion
An injury of a part of the brain without the break of the skin (general)
Coup - collision of the brain with skull at the site of the impact
Contrecoup - blow on one side of the head with damage on the cerebral hemisphere of the opposite side, by transmitted force
Define concussion
Loss of consciousness, transient or prolonged due to a blow to the head; there may be transient amnesia, temporary respiratory arrest and loss of reflexes
What is cerebral contusion?
Bruising of the brain caused by rapid tissue displacement, disruption of vascular channels, and subsequent haemorrhage, tissue injury and edema
What causes penetration of the brain?
By a projectile, such as bullet or skull fragment from a fracture causes laceration. Tissue tearing, vascular disruption and haemorrhage occurs.
What’s diffuse axonal injury?
Movement of one region of brain relative to another that leads to the disruption of axonal integrity and function.
What’s traumatic vascular injury and list the sites of haemorrhage
Direct trauma and disruption of the vessel walls, leading to haemorrhage
E - Epidural
S - Subdural
S - Subarachnoid
I - Intraparenchymal
Explain about epidural haemorrhage and hematoma.
It is due to the rupture of vessels that runs along the dura, mainly middle meningeal artery during skull fracture. Once torn, accumulation of blood under arterial pressure causes separation of the dura from the inner surface of the skull, and the expanding hematoma that forms compresses the brain. It’s a neurosurgical emergency that requires prompt drainage.
What’s subdural haemorrhage and hematoma.
Rapid movement of the brain that tears the bridging veins that extends from the cerebral hemisphere through subarachnoid and subdural space to empty into dural sinuses. The disruption leads to bleeding into subdural space.
Who are susceptible to subdural haemorrhage?
Elders - atrophy of brain makes the veins to be stretched out and that the brain has space for movement
Infants - due to thin walled vessels
Clinical manifestations of subdural haemorrhage
Headache, confusion and focal neurological signs
Outcomes of traumatic head injury
- Post traumatic epilepsy (most common)
- Persistent vegetative state (severely neurological impaired)
- Post traumatic dementia (due to neuronal loss and axonal damage)
Types of spinal cord injury?
Open injury - direct trauma to spinal cord and nerve root
Closed injury - fracture/dislocation of vertebral column
List the types of intracranial haemorrhage
- Intraparenchymal/cerebral haemorrhage
- Subarachnoid haemorrhage
- Epidural and subdural haemorrhage
- Mixed type
What causes Intraparenchymal haemorrhage?
Caused by rupture of small Intraparenchymal vessels which is a consequence of hypertension.
*HT is the main cause
Where does hypertensive Intraparenchymal haemorrhage occurs and what are the abnormalities of blood vessels caused by H/T?
Typically it occurs at : basal ganglia, thalamus, pons, cerebellum
Abnormalities caused : speeds up atherosclerosis in large arteries, hyaline arteriolosclerosis in small vessels, proliferative and necrosis of arteriole in severe cases
Morphology of Intraparenchymal haemorrhage
Gross
Acute haemorrhage - blood extravasation with adjacent parenchyma compression
Old haemorrhage - cavitary destruction of brain with a rim of brownish discoloration
Microscopic
Early - central core of clotted blood surrounded by rim of brain tissue showing anoxic neuronal & glial changes, and edema
Edema resolves eventually, pigment and lipid laden macrophages appear and reactive astrocyte proliferation are seen at the periphery
What’s the clinical features of Intraparenchymal haemorrhage?
S/s of increased ICP : severe headache, vomiting, papilloedema, rapid loss of consciousness
Evidence of brain stem compression : deep coma, irregular respiration with apnoea, dilated non responsive pupil with spasticity
What causes subarachnoid haemorrhage and the consequences?
Rupture of saccule aneurysm is the most common cause, followed by tumour trauma, vascular malformation and hematological disorders.
When rupture occurs, blood is forced into subarachnoid space. Individuals have sudden excruciating headache and loses consciousness rapidly.
Forum principle types of vascular malformation
- Arteriovenous malformation
- Cavernous angiomas
- Capillary talengiectasias
- Venous angiomas
