Neurology 3 Flashcards
SDH - definition
This is a treatable condition that should be considered in a patient with a fluctuating conscious level or in those having an ‘evolving stroke’ – especially those on anticoagulants.
SDH - bleeding and risk factors
- Bleeding – bridging veins between the cortex and venous sinuses are vulnerable to de-acceleration resulting in an accumulating haematoma between the dura and the arachnoid mater. This gradually increases ICP, pushing the midline structures away and leading to tentorial herniation and coning.
- Risk factors – the elderly are more susceptible due to brain atrophy making bridging veins vulnerable. Other risk factors include history of falls (e.g. in epileptics or alcoholics) and anticoagulation.
SDH - symptoms and signs
- Symptoms – can emerge up to 9 months after an event – fluctuating level of consciousness, insidious physical or intellectual slowing, unsteadiness, sleepiness, headache or personality changes.
- Signs – raised intracranial pressure (headache, drowsiness, vomiting, pupil changes or papilloedema), seizures or localising neurological symptoms e.g. hemiparesis (occurring mean 63 days after injury).
SDH - differential diagnosis
Stroke, dementia or CNS masses – tumours or cerebral abscess.
SDH - investigations
CT or MRI shows the clot and midline shift – look for crescent shaped collection of blood over 1 hemisphere – the sickle shape differentiated subdural from extradural haemorrhage.
SDH - management
Evacuation – 1st line is burr twist drill or hole craniostomy and 2nd line is craniotomy.
EDH - definition and bleeding
- When blood accumulates between the dura mater and the bony skull. Suspect an EDH after a head injury if conscious level falls or is slow to improve or if there is a lucid interval.
- Bleeding – usually due to a fractured temporal or parietal bone causing laceration of the middle meningeal artery and vein. This typically occurs after trauma to a temple just lateral to the eye.
EDH - symptoms
The lucid interval may last a few hours to a few days before the patients GCS begins to fall caused by raised ICP – severe headache, vomiting, confusion and seizures typically follow with or without focal neurological signs – hemiparesis with brisk reflexes and an up-going plantar. If bleeding continues – ipsilateral pupil dilation, coma, bilateral limb weakness and deep and irregular breathing.
EDH - differential diagnosis
Epilepsy, carotid dissection (spontaneous or traumatic) or CO poisoning.
EDH - investigations
CT shows a lens shaped haematoma (more rounded shape than SDH) and skull x-ray may show evidence of fracture lines crossing the course of the middle meningeal vessels.
EDH - management
Stabilise and transfer urgently to a neurosurgical unit for clot evacuation ± ligation of the bleeding vessel. Starting an IVI of mannitol (osmotic agent) can help reduce the raised ICP.
Epilepsy - definition
A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain which manifests as seizures. Convulsions are the motor signs of electrical discharge.
Elements of a seizure
- Prodrome – a change in mood or behaviour that can occur in hours to days before the seizure.
- Aura – part of the seizure of which the patient is aware – could be strange feeling in stomach, déjà vu (sense of familiarity), strange smells or flashing lights – implies a partial seizure.
- Post-ictally – headache, confusion, myalgia, a sore tongue, temporary weakness following a focal motor cortex seizure or temporary dysphasia following a focal temporal seizure.
Partial seizures
Focal onset with features referable to a part of one hemisphere:
- Simple partial – awareness is unimpaired with focal motor, sensory (e.g. olfactory or visual), autonomic or psychic symptoms. There are no post-ictal symptoms.
- Complex partial – awareness is impaired and seizures most commonly arise in the temporal lobe and cause post-ictal confusion. Frontal seizures have a rapid recovery.
- Partial with secondary generalisation – in 2 thirds of patients with partial seizures the electrical disturbance spreads causing a 2° generalised seizure – usually convulsive.
Generalised seizures
Simultaneous onset of electrical discharge throughout the cortex.
- Absence – brief (
- Tonic clonic – loss of consciousness when limbs stiffen (tonic) and then jerk (clonic).
- Myoclonic – a sudden jerk of the limb, face or trunk – patient may fall to the ground.
- Atonic – a sudden loss of muscle tone causing a fall with no loss of consciousness.