Im Flashcards
Seizure ,Convulsion ,Epilepsy
Definition
• Seizure is brain, whilst epilepsy is the occurrence of more than one unprovoked seizure more than 24 hours apart.
• Convulsion is a seizure with intense motor component.
• The lifetime risk of having a single seizure is about 5%.
• Epilepsy should be regarded as a symptom of brain disease rather than a disease itself.
Epilepsy
Pathology
• It is likely that both reduction in inhibitory systems and excessive excitation in the brain play a part in the genesis of seizure activity.
• The inhibitory transmitter gamma-aminobutyric acid (GABA) is particularly important in this role, and drugs that block GABA receptors provoke seizures.
• Conversely, excessive stimulation by excitatory acetylcholine, glutamate, provoke seizure activity.
neurotransmitters
e.g.
• Cells undergoing repetitive ‘epileptic’ discharges undergo morphological and physiological changes which make them more likely to produce subsequent
abnormal discharges (‘kindling’).
Clinical classification of seizures
- Partial seizures
a. Simple partial seizures (with motor, sensory, autonomic, or psychic signs)
b. Complex partial seizures
c. Partial seizures with secondary generalization 2. Primarily generalized seizures
a. Absence (petit mal)
b. Tonic-clonic (grand mal)
c. Tonic
d. Atonic
e. Myoclonic
- Unclassified seizures
a. Neonatal seizures
b. Infantile spasms
Tonic clonic seizures (grand mal epilepsy)
Absence seizures (petit mal)
Cf
-GENERALISED
Tonic clonic seizures (grand mal epilepsy)
1- A tonic clonic seizure may be preceded by a partial seizure (the ‘aura’).
2-Tonic phase: The patient goes rigid and becomes unconscious, falling down heavily if standing and often sustaining injury. Respiration is arrested and central cyanosis may be witnessed. Contraction of the jaw muscles may cause biting of the tongue.
3- Clonic phase: rigidity is periodically relaxed, producing clonic jerks
4- Postictal phase: is characterized by unresponsiveness, muscular flaccidity, and excessive salivation. Bladder or bowel incontinence may occur at this point.
Absence seizures
• Absence seizures (petit mal) always start in childhood. The child stares
fixedly
with eyes turned upward, blinks, and may make movements of the tongue or
mouth, or pick at his or her clothes.
Patients gradually regain consciousness over minutes to hours, and during this transition there is typically a period of postictal confusion. Patients subsequently complain of headache, vomiting, fatigue, and muscle ache that can last for many hours. Full memory function may not be recovered for some hours.
Absence seizures vs. complex partial seizures
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GENERALISED
Absence seizures
• Absence seizures (petit mal) always start in childhood. The child stares
fixedly
with eyes turned upward, blinks, and may make movements of the tongue or
mouth, or pick at his or her clothes.
• The examining physician may be able to provoke an absence by having the patient hyperventilate.
• Typical absence seizure may show the typical 3 HZ cycle in the EEG.
complex partial seizures/
shorter in duration
they occur much more frequently (20-30/ day)
and are not associated with post-ictal confusion.
Partial seizures
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-PARTIAL
Partial seizures are always due to a circumscribed lesion in the brain. Partial seizures may occur with the patient remaining fully conscious (simple partial seizures). They can, however, involve an impairment of consciousness, in which case they are called complex partial seizures.
Partial motor seizures
• Seizures are characterised by rhythmical jerking or sustained spasm of the affected parts.
• Some attacks begin in one part (e.g. mouth, thumb, great toe etc.) and spread gradually; this is ‘Jacksonian march’.
• More prolonged episodes may leave paresis of the involved limb lasting for
several hours after the seizure ceases (Todd’s palsy).
Partial sensory seizures
• Seizures arising in the sensory cortex cause unpleasant tingling or ‘electric’ sensations in the contralateral face and limbs.
• A spreading pattern like a Jacksonian seizure may occur, the abnormal sensation spreading much faster over the body (in seconds) than the ‘march’ of a migrainous focal sensory attack, which spreads over 10-15 minutes.
Complex partial seizures
Partial seizures with secondary generalization
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Partial
Complex partial seizures
• Partial seizures may cause episodes of altered consciousness without the patient collapsing to the ground.
• The patient stops what he or she is doing and stares blankly. • This behavioral arrest is usually accompanied by automatisms, which are involuntary, automatic behaviors that have a wide range of manifestations.
• Automatisms may consist of very basic behaviors such as chewing, lip smacking, swallowing, or “picking at their clothes.” movements of the hands.
• The patient is typically confused following the seizure, and the transition to full recovery of consciousness may range from seconds up to an hour.
•
Immediately before such an attack the patient may report alterations of mood, memory and perception such as undue familiarity (déjà vu) or unreality (jamais vu), complex hallucinations of sound, smell, taste, vision, emotional changes (fear, sexual arousal) or visceral sensations (nausea, epigastric discomfort).
Partial seizures with secondary generalization
• Generalised epilepsy may arise from spread of partial seizures.
• Epilepsy presenting in adult life is almost always secondary generalised, even if there is no clear history of a partial seizure before the onset of a major attack.
Differential diagnosis of seizure are:
Features make the diagnosis of seizure more likely:
• Differential diagnosis of seizure are:
- Syncope
- Migraine
- Transient ischemic attacks
- Hypoglycaemia
- Psychogenic seizure (pseudoseizure)
• Features make the diagnosis of seizure more likely:
- Aura
- Stereotyped attacks
- Cyanosis
- Post-ictal confusion
- Post-ictal amnesia
- Post-ictal headache
- Developed during sleep
- Loss of continence
- Causing injury
- Biting “lateral border” of the tongue
• The general physical examination includes a search for signs of infection or systemic illness (liver or renal disease), signs of head trauma and use of alcohol or illicit drugs.
Epilepsy
Ix
- Routine blood studies are indicated to identify the more common metabolic causes of seizures.
- EEG:
• In the evaluation of a patient with suspected epilepsy, the presence of electrographic seizure activity during the clinically evident event clearly establishes the diagnosis.
• The absence of electrographic seizure activity does not exclude a seizure disorder.
• Inter-ictal records are abnormal in only about 50% of patients so the EEG is not
a sensitive test for the presence or absence of epilepsy. • Specific epileptiform changes include sharp waves or spikes.
3-Brain imaging:
• Imaging can never establish a diagnosis of epilepsy but is useful in defining or excluding a structural cause.
Epilepsy
Mgx
Immediate management of seizures
- Move person away from danger (fire, water, machinery, furniture)
- After convulsions cease, turn into ‘recovery’ position (semi-prone) 3. Ensure airway is patent
- Give oxygen
- Secure an intravenous access and Draw blood for glucose,urea, electrolytes and drug or toxin.
- Give intravenous anticonvulsant (e.g. diazepam 10 mg) ONLY IF convulsions are continuous or repeated
- Do NOT insert anything in mouth
- Person may be drowsy and confused for some 30-60 minutes and should not be left alone until fully recovered
- Investigate cause
• Patients should be made aware of the riskiness of any activity where loss of awareness would be dangerous (driving, swimming, boating) until good control of seizures has been established.
Anticonvulsant drug therapy
• Drug treatment should certainly be considered after more than one seizure has
occurred.
• The mode of action is either to increase inhibitory neurotransmission in the brain or to alter neuronal sodium channels in such a way as to prevent abnormally rapid transmission of impulses.
• Phenytoin and carbamazepine are not ideal agents for a young woman wishing to use oral contraception, because the drugs induce liver enzymes.
• The choice of antiepileptic drug depends on seizure type, patient age, side effect profile of the drug, comorbid illness, drug cost.
•
After complete control of seizures for 5 years, withdrawal of medication may be considered.
• Withdrawal should be undertaken slowly, reducing the drug dose gradually over 6-12 months.
• Overall, the recurrence rate of seizures after drug withdrawal is about 40%.
Physiology of ICP:
Causes of raised ICP
Clinical features of raised ICP
Physiology of ICP:
• The skull is a fixed structure not allowing expansion.
• Intracranial volume consists of three compartments: brain, blood, CSF. If the volume of one of these compartments increases, the volume of another must decrease to maintain normal ICP (50-180mm water).
• If the CSF pressure is further increased the brain may begin to herniate, then cerebral perfusion pressure will drop and ischemia result.
Causes of raised ICP
A. Space-occupying mass, for example, brain tumor, abscess, hematoma.
B. Brain oedema
C. Hydrocephalus
D. Venous thrombosis: impairs CSF reabsorption
E. Idiopathic intracranial hypertension
Clinical features of raised ICP
a. Headache
b. Morning vomiting
c. Papilloedema
d. Impairment of conscious level
e. Hypertension and bradycardia
f. Transient visual obscurations
g. False localizing signs
h. Herniation
Types of Brain edema (increase in brain water)
- Vasogenic edema: extracellular disturbance of BBB, localized around tumors, abscesses, hemorrhages, and localized cerebral contusions. It may lead to herniation.
- Cytotoxic edema: intracellular, hypoxia (cardiac arrest), intoxication, severe hypothermia,. It is usually generalized.
- Osmotic edema: ECF, abnormal ADH secretion, severe hemodialysis, or excessive ingestion of water (hysterical)
- Hydrostatic edema: ECF due to acute hypertension.
Raised ICP
Types of herniation
- Subfalcine: Displacement of the cingulate gyrus under the falx and across the midline.
- Transtentorial downward movement of the thalamic region through the opening of the tentorium cerebelli.
- Uncal herniation: The uncinate process of the temporal lobe herniates into the anterior part of the opening of the tentorium cerebelli. 4. Transcalvarial: Displacement of brain through a defect in the skull, such as a fracture site or following craniectomy.
- Upward herniation (reverse coning): a posterior fossa mass lesion may lead to upwards transtentorial herniation of posterior fossa contents.
- Tonsillar (cerebellar) herniation: Downward herniation of the cerebellar tonsils into the foramen magnum.
• Cerebellar herniation (coning) may result in brain-stem haemorrhage and/or acute obstruction of the CSF pathways. As coning progresses, coma with decerebrate posturing occurs and death almost invariably ensues.
• Herniation may be acutely accelerated if the pressure dynamics are suddenly disturbed by lumbar puncture or CSF drain.
False localising signs
a) Pupillary dilatation
b) 6th cranial nerve lesion (unilateral or bilateral)
c) Hemiparesis
d) Bilateral extensor plantar responses
Elevated ICP
Ttt
a) Elevate head of the bed; midline head position
b) Osmotherapy—mannitol or hypertonic saline.
c) Glucocorticoids—dexamethasone 4 mg q6h for vasogenic edema from tumor, abscess (avoid glucocorticoids in head trauma, ischemic and hemorrhagic stroke).
d) Hyperventilation
e) High-dose barbiturate therapy (“pentobarb coma”)
f) Hypothermia
g) Hemicraniectomy
IDIOPATHIC INTRACRANIAL HYPERTENSION
Definition
Cf
Ix
Mgx
• This condition usually occurs in obese young women.
• The aetiology is uncertain but there may be a diffuse defect of CSF reabsorption by the arachnoid villi.
• The condition can be precipitated by drugs, including tetracycline, and rarely vitamin A, retinoids, Addison’s disease and withdrawal of corticosteroid therapy.
Clinical features
• Characteristically, there is a headache (raised ICP headache), sometimes with transient diplopia and visual obscurations, but few other symptoms.
• There are usually no signs other than papilloedema, but 6th nerve palsy may be present.
Investigations 1-Brain CT is normal 2-Lumbar puncture is safe and will allow confirmation of the raised CSF pressure and form part of treatment.
3-MRV (magnetic resonance venography) to exclude cerebral vein thrombosis 4-Thyroid function test to exclude hypothyroidism.
Management
- Any precipitating condition should be sought and treated.
- weight-reducing diet
- The carbonic anhydrase inhibitor, acetazolamide, may help to lower intracranial pressure.
- Repeated lumbar puncture and CSF aspirate can be considered, but is often unacceptable to the patient.
- Patients failing to respond, in whom chronic papilloedema threatens vision, may require optic nerve sheath fenestration or a lumbo-peritoneal shunt.
Nervous system infections are classified upon the location of the infection
The meningitic syndrome
• Nervous system infections are classified upon the location of the infection into
- Meningitis(infection of the meninges)
- Encephalitis(infection of the parenchyma of the brain)
- Brain abscess and subdural empyema : focal suppurations
• The meningitic syndrome is simple triad: headache, neck stiffness and fever. Photophobia and vomiting are often present. In acute bacterial infection there is usually intense malaise, fever, rigors, severe headache, photophobia and vomiting. This develops within hours or minutes. The patient is irritable and often prefers to lie still. Neck stiffness and positive Kernig’s sign usually appear within hours.
VIRAL MENINGITIS
• Viral infection is the most common cause of meningitis, and usually results in a benign and self-limiting illness requiring no specific therapy.
• A number of viruses can cause meningitis the most common being enteroviruses.
• The condition occurs mainly in children or young adults.
• Characterized by acute onset of headache and irritability and the rapid development of meningism.
• The CSF usually contains an
excess of lymphocytes,
normal glucose
and the protein level may be raised.
• Treatment is symptomatic; the condition is usually benign and self-limiting.
Recovery usually occurs within days.
PYOGENIC BACTERIAL MENINGITIS
Definition
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Ix
• Streptococcus pneumoniae is the most common cause of bacterial meningitis, followed by Neisseria meningitidis.
• The meningococcus and other common causes of meningitis are normal commensals of the upper respiratory tract. New and potentially pathogenic strains are acquired by the air-borne route, but close contact is necessary.
• The organism invades through the nasopharynx, producing septicemia that is usually associated with pyogenic meningitis.
• In pneumococcal and Haemophilus infections there may be an associated otitis media. Pneumococcal meningitis may be associated with pneumonia and occurs especially in older patients and alcoholics, as well as those with asplenia.
• Listeria monocytogenes can cause meningitis in the immunosuppressed, diabetics, alcoholics, pregnant women, as well as in the extremes of age. Clinical features
• Headache, drowsiness, fever and neck stiffness are the usual presenting features.
• In severe bacterial meningitis the patient may be comatose and later there may be focal neurological signs.
• Meningococcal meningitis may be associated with a purpuric rash.
Investigations:
Symptoms& signs of meningitis
↓
Blood culture, throat swab
↓
Empirical antibiotics
↓
Brain CT scan to exclude space occupying lesions
↓
Lumbar puncture
• In bacterial meningitis the CSF is cloudy (turbid) due to the presence of many neutrophils, so called septic meningitis.
• Gram stain and culture of CSF may allow identification of the organism.
• Polymerase chain reaction (PCR) techniques can be used on both blood and CSF to identify bacterial DNA
PYOGENIC BACTERIAL MENINGITIS
Mgx
Prognosis
Management:
• If bacterial meningitis is suspected, parenteral (i.v.) empirical antibiotics should be given immediately before the cause of meningitis is known.
• The antibiotic regimen may be modified after identifying the infecting organism.
• Duration of antibiotic treatment depends on the infecting organism, but usually for 2-3 weeks.
• Adjunctive corticosteroid therapy is useful in both children and adults. Dexamethasone (10 mg intravenously) should be administered 20 min before or concurrent with the first dose of antibiotics and the same dose is repeated every 6 h for 4 days.
• Household and other close contacts of patients with meningococcal infections, especially children, should be given 2 days of oral rifampicin (age 3-12 months 5 mg/kg 12-hourly, > 1 year 10 mg/kg 12-hourly, and adults 600 mg 12-hourly). In adults, a single dose of 500 mg of ciprofloxacin is an alternative.
Prognosis:
In general, the risk of death from bacterial meningitis increases with
(1) decreased level of consciousness on admission,
(2) Onset of seizures within 24 h of admission,
(3) Signs of increased ICP
(4) Young age (infancy) and age >50
(5) Delay in the initiation of treatment.
(6)Decreased CSF glucose concentration (<40 mg/dL)
(7) Markedly increased CSF protein concentration (>300 mg/dL)
Chronic meningitis
Chronic meningitis is most commonly diagnosed when meningitic syndrome exists for > 4 weeks and is associated with a persistent inflammatory response in the (CSF). Causes include:
1-meningeal infections (e.g. TB, brucella, fungal).
2-malignancy (carcinomatous, leukemic) 3-noninfectious inflammatory disorders (sarcoidosis, SLE) 4-chemical meningitis (drugs) 5-parameningeal infections (otitis media, mastoiditis)
Tb meningitis
Definition
Cf
Ix
Mgx
TUBERCULOUS MENINGITIS
• Tuberculous meningitis remains common in developing countries and is seen as a secondary infection in patients with AIDS.
• Occurs most commonly shortly after a primary infection in childhood or as part of miliary tuberculosis.
• The usual local source of infection is a caseous focus in the meninges or brain substance adjacent to the CSF pathway.
• The brain is covered by greenish, gelatinous exudates, especially around the base of the brain.
Clinical features of tuberculous meningitis:
Symptoms
• Headache
• Vomiting
• Low-grade fever
• Lassitude
• Confusion
• Behaviour changes
Signs
Meningism
Oculomotor palsies
Papilloedema
Focal hemisphere signs
Depression of conscious level
Investigations
• Brain CT to exclude SOL. It may show hydrocephalus, tuberculoma.
• CSF study: high CSF pressure, CSF is clear but, when allowed to stand, a fine clot (‘spider web’) may form, up to 5 × 10 8 cells/litre, predominantly lymphocytes, a rise in protein and a marked fall in glucose. AFB may be positive in CSF smear.
• Chest X-ray to exclude pulmonary TB.
Management
• As soon as the diagnosis is made or strongly suspected, chemotherapy should be started.
• Initial therapy is a combination of isoniazid (300 mg/d), rifampin (10 mg/kg per day), pyrazinamide (30 mg/kg per day in divided doses), ethambutol (15–25 mg/kg per day in divided doses), and pyridoxine (50 mg/d). If the clinical response is good, pyrazinamide and ethambutol can be discontinued after 8 weeks and isoniazid and rifampin continued alone for the next 6–12 months.
• Adjunctive therapy with corticosteroid can be used for several weeks.
• Surgical ventricular drainage may be needed if obstructive hydrocephalus develops.
VIRAL ENCEPHALITIS
Definition
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Ix
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Prognosis
VIRAL ENCEPHALITIS
• Encephalitis is infection of the substance of the nervous system (mostly the brain) producing symptoms of focal dysfunction (focal deficits and/or seizures) with general signs of infection.
• Viruses are the most common cause.
• The most serious cause of viral encephalitis is herpes simplex which probably reaches the brain via the olfactory nerves.
• In herpes simplex encephalitis, the temporal lobes are usually primarily affected. Clinical features:
• Acute onset of headache, fever with or without meningism.
• focal neurological signs (aphasia and/or hemiplegia) and seizures (focal or generalized)
• Disturbance of consciousness ranging from drowsiness to deep coma, or confusion.
Investigations:
• Brain CT scan may show low-density lesions in the temporal lobes.
• MRI is more sensitive in detecting early abnormalities.
• Lumbar puncture: The CSF usually contains excess lymphocytes, protein content may be elevated but the glucose is normal. Occasionally, the CSF is normal.
• PCR is necessary for detection of CSF.
• The EEG is usually abnormal in the early stages. Management:
• Herpes simplex encephalitis responds to acyclovir 10 mg/kg i.v. 8-hourly for 2-3 weeks. This should be given early to all patients suspected of suffering from viral encephalitis.
• Anticonvulsant treatment is often necessary.
• Raised intracranial pressure is treated with dexamethasone 8 mg 12-hourly. Prognosis:
Even with optimum treatment, mortality is 10-30% and significant proportions of survivors have residual epilepsy or cognitive impairment.
Tetanus
Definition
Pathology
Cf
Not uncommon in developing countries
Cause: Clostridium tetani ( G+ve rods, anaerobe, spore forming) a commensal in the gut of humans and domestic animals.
Habitat: heat and anti-septic –resistant spores in soil (mainly through fecal material of animals, and human!; and human reservoir Entry to human body; in anaerobic conditions like T. necrosis, spores form, bacteria produce exotoxin •
Tetanus is often associated with rust, especially rusty nails. Although rust itself does not cause tetanus, objects that accumulate rust are often found outdoors or in places that harbor anaerobic bacteria. Pathophysiology
Exotoxin: tetano-spasmin Blood-borne transport to local motor endplate Retrograde axonal transport to CNS Sites of action:
• Spinal cord and brainstem inhibitory neuron ( Renshaw cells) Clinical features
Incubation period: 1-2 days to 1 month
• lock jaw is an early feature
• Repeated body spasms
• opsithotonus Localized: benign course, resolution with no residual effects Generalized: severe, mild fever, neck stiffness, then bulbar involvement then limb & trunk; can be seen in neonates ( tetanus neonatorum)
Cephalic: bulbar and facial weakness and spasms, worst prognosis
In the severe cases, violent spasms lasting for few seconds to 3-4 minutes occur spontaneously , or may be induced by stimuli such as movement or
noises Spasms are painful and exhausting
Tetanus
Dx
Causes of Death
Ttt
Prevention
Summary
Diagnosis
A clinical one!
Organism rarely isolable by the time of presentation.
Hx of injury; dirty wounds Causes of death
• Laryngospasm, apnea
• Heart failure, arrhythmia
• Shock
• Aspiration pneumonia Treatment
•Immediate measures
•Antitoxin (3000-6000 units, IV )
•Antibiotic (Penicillin, metronidazole or tetracycline , 10 day course)
•Nurse in quiet dark room
•Debridement of wound, Rx of secondary infections
•ICU nursing ( environment, tracheostomy)
•muscle relaxants like diazepam, phenobarbitone Prevention
Active immunization (DTP); 3 doses; routine in Iraq Every 10 years, a booster should be administered
Toxoid is indicated in
•
•
moderate/high risk wounds when patient hasn’t received a booster in the last 5 years any open wounds when patient hasn’t received a booster within last 10 years
Patients with moderate/high wounds should receive IM anti-toxin Summary
The only vaccine preventable disease that is infectious but not contagious!
Mortality : 50%, tetanus neonatorum :100% in developing countries Good prognosis:
Localized, early treatment
Rabies
Mode of transmission
Pathology
Cf
Dx
Mgx
Prevention
Pre-exposure prophylaxis
Mode of transmission
• Saliva ( bites, licks of broken skin or mucus membrane)
• Iatrogenic (corneal transplants)
Pathophysiology
Causative agent: RNA virus, a Rhabdovirus Retrograde axonal transport to CNS Targets of infection: CNS( brainstem) and salivary glands Pathology:
• Rhombencephalitis
• Negri bodies (hippocampus, Purkinji cells) Clinical features
Incubation period: 4-8 weeks, as minimum as 9 days (multiple, necks, face, scalp bites) History of bite Prodrome: fever, headache, parasthaesia around bite (characteristic) Encephalitis versus paralytic phenotypes:
Furious/ rabid/ encephalitic rabies: agitation, confusion, seizures, insomnia, hallucinations, characteristic hydrophobia Paralytic/ dumb rabies: severe weakness, preserved sensorium Coma Death (100% of clinically evident cases) usually within 7 days of onset of symptoms Management
Diagnosis: a clinical one PCR ( CSF, hair follicle, corneal smear preparation) Post mortem examination for confirmation
What to do in established case? Really nothing Treatment is supportive and palliative, isolation Intensive care setting Prevention
Wound washing with soap and benzyl ammonium chloride Post-exposure:
Active: HDCV 1 ml IM, on day 0,3,7,14,28 (30), (90) Passive: HRIG 20U/kg ½ IM, ½ infiltration around wound If HRIG is not available, 0.1 ml of HDCV ID at 8 sites on day 1, single boosters on day 7 & 28 If no human products available, observe the animal for 10 days or euthanize if S&S of rabies!
Pre-exposure prophylaxis: HDCV 0.1 ml, two IM injections
Poliomyelitis
Causative agent
Transmission
Cf
Dx
Prevention and prognosis
Ddx
Causative agent: 3 polioviruses….Enteroviridae. ( RNA viruses)
Mode of transmission: faeco-oral
Clinical features
Incubation period: 3-35 days, average 6-20 days Pre-paralytic: pharyngitis, headache, fever, muscle aches, tenderness
Paralysis: peaks with maximal fever, within 24-48 hours, doesn’t progress when fever is settled for two days, asymmetrical, proximal, lower limbs mainly flaccid weakness (injection, physical activity are risk factors)
Wasting apparent after 3 weeks, maximal by 12-16 weeks Three phenotypes:
Spinal(79%);Bulbar( 2%); Bulbospinal (19%) Management
Diagnosis:
Isolation of virus from stool or pharynx Rarely isolable from CSF!
CSF examination: lymphocytic pleocytosis ↳ Viral Treatment: infection
Supportive: avoid IM injection, exercise.
Prevention:
Sabin vaccine (OPV) live attenuated, (herd immunity), Salk (IPV)
vaccine prognosis
Mortality due to respiratory failure, autonomic dyregulation
•
•
•
Children: 2-5% Adults: 15-30% Bulbar polio: 25-75%!!!
Differential diagnosis
•
•
Guillian Barre’ syndrome (AIDP)
Polio-like syndromes: Coxsackie A &B, Japanese encephalitis West Nile virus
Subacute sclerosing panencephalitis
Definition
Ix
Ttt
Subacute sclerosing panencephalitis Rare progressive and eventually fatal illness Is a complication of measles May develop many years after the primary measles Intellectual deterioration, poor school performance, apathy followed by myoclonic jerks, rigidity and dementia Brain MRI is often normal.
EEG non specific slowing but later on characteristic periodic changes appear.
CSF high protein , anti measles antibody are invariably elevated.
Antiviral therapy isoprinosine Intrathecal alpha interferon may be beneficial.
Prion diseases
Prion diseases
Prions are unique amongst infectious agents in that they’re devoid of any nucleic acid.
PrP c normal protein in brain shifted to abnormal PrPsc
Accumulation of encephalopathy
PrP
sc causes a transmissible spongiform
Human prion diseases are characterized by the histopathological triad of cortical spongiform change, neuronal
loss and gliosis.
Creutzfeldt-Jakob disease
Creutzfeldt-Jakob disease Is a human prion disease · 10% due to mutation in the gene coding for prion protein Middle age and elderly Rapid progressive dementia, myoclonus, ataxia and visual disturbance Characteristic EEG abnormality No treatment
DISORDERS OF THE SPINE AND SPINAL CORD
Anatomy
DISORDERS OF THE SPINE AND SPINAL CORD
Anatomy:
• Spinal cord is the component of the central nervous system that connects the brain to the peripheral nerves.
• It contains:
a) in the white matter, fiber pathways leading from the brain to the periphery and vice versa
b) In the gray matter, an intrinsic neuronal system; motor, somatosensory, autonomic and interneurons.
• Anterior 2/3 of cord is supplied by anterior spinal artery while posterior 1/3 is supplied by posterior spinal arteries.
Spinal cord transection syndrome
Spinal cord transection syndrome: is the pattern of neurological deficits resulting from damage of the entire cross-section of the spinal cord at some
level.
• It is traumatic, ischemic, infectious or inflammatory (transverse myelitis).
• The clinical features of the spinal cord transection syndrome are:
I. there is a sensory level below which all modalities of sensation are impaired
II. Bilateral pyramidal tract dysfunction: spastic paraplegia, or, with cervical lesions, spastic quadriplegia (immediately there may be usually flaccid weakness “spinal shock”, which subsequently becomes spastic).
III. sphincter dysfunction
Spinal cord hemisection syndrome (Brown−Séquard syndrome)
Spinal cord hemisection syndrome (Brown−Séquard syndrome)
• Caused by a compressing tumor or demyelination.
• Clinical features include:
I. Ipsilateral paresis
II. Ipsilateral loss of proprioception and vibration sense
III. Contralateral loss of pain and temperature sensation
Central cord syndrome
Central cord syndrome
• Is the classic presentation of syringomyelia but can also be due to an
intramedullary hemorrhage or tumor.
• In the cervical cord, the central cord syndrome produces arm weakness out of proportion to leg weakness
• “Dissociated” sensory loss, signifying a loss of pain and temperature sense in a cape distribution over the shoulders, lower neck, and upper trunk in contrast to preservation of light touch, joint position, and vibration sense in these regions.
