MS, meningitis and coma Flashcards
MS incidence
1.2 per thousand
MS geography
More common away from the equator, and in white populations.
MS age
Initial presentation between 20 and 40 (patient I saw started in teens). Later if primary progressive.
MS sex
Women twice as likely, ratio widening.
MS likely presenting symptoms
Optical neuropathy
Brainstem demyelination symptoms
Spinal cord lesion symptoms
MS optical neuropathy
central loss of vision, can be foggy or dense
MS brainstem demyelination symptoms.
Diplopia, vertigo, facial weakness/numbness, dysarthria and dysphagia. Pyramidal signs in limbs can also occur.
MS spinal cord lesions symptoms
Paraparesis, tingling or numbness on walking. Tightness around chest.
MS clinical signs.
Lhermitte’s sign
MS clinical symptoms that are less often presenting.
Other visual changes, strange sensations on skin, clumsiness, unsteadiness, urinary symptoms, pain, fatigue, spasticity, depression and sexual dysfunction.
Rare but pathognomic: tonic spasms.
MS investigations.
MRI of brain and spinal cord - latter useful for specificity to inflammatory disorders e.g. MS.
MS diagnosis
Two attacks separated in time affecting different parts of CNS. Important to ask about any previous neurological symptoms. MRI imaging.
MS treatment
No cure. Treat individual symptoms.
Acute relapses treat with steroids.
Some immunomodulatory treatments are disease modifying. B-interferon and galtiramer.
MS pathology - overview
T cell mediated autoimmune inflammatory disorder leading to demyelination of brain and spinal cord.
MS pathology - plaque size
2 - 10 mm in size.
MS pathology - common places for plaques to form
Optic nerves, periventricular region, corpus callosum, brainstem and cervical cord.
MS disease progression overview.
Relapsing-remitting (common) most of which evolve into secondary progressive. A few start with primary progressive.
Indications for a CT head.
GCS is either less than 13, or 13/14 2h after injury. Focal neurological deficit, post traumatic seizure, suspected skull fracture and vomiting more than once.
Loss of consciousness AND > 65 yr, or coagulopathy, or dangerous mechanism of injury, or anterograde amnesia for greater than 30 minutes.
Common causes of predominantly motor peripheral neuropathies.
Guillain-Barré syndrome, Charcot-Marie-Tooth syndrome, porphyria, lead poisoning and diphtheria.
Common causes of peripheral painful neuropathy
alcoholic neuropathy, diabetic amyotrophy, porphyria, vitamin B1 deficiency or vitamin B12 deficiency and carcinoma
Common causes of peripheral neuropathy
Diabetic neuropathy.
Nutritional, including alcohol (with or without vitamin B1 deficiency), B12 deficiency
Clinical features of shingles
Tingling or pain preceding vesicular rash usually in dermatomal distribution.
Can be followed by post-herpetic neuralia, CNV and VII involvement and myelitis.
Treatment of shingles
Aciclovir 800mg 5 times/d, PO for 7 d
Clinical features of sagittal venous sinus thrombosis
Headache, vomiting, seizures, deteriorating vision, papilloedema.
Cinical features of transverse venous sinus thrombosis
headache +/- mastoid pain, focal CNS deficit, seizures, papilloedema.
Differential diagnosis with dural venous sinus thrombosis
SAH
meningitis
encephalitis
Investigations for dural venous sinus thrombosis
MRI T2 may visualise directly
CT after 1 wk can show delta sign: transversely cut sinus shows contrast filling defect.
Treatment of dural venous sinus thrombosis
Escalate to specialist
heparin
sometimes fibrinolytics
Prognosis for dural venous sinus thrombosis
Variable
Questions for blackout.
Previous episodes?
What was pt doing? (situational syncope)
Symptoms preceding blackout? Chest pain/palpitations (cardiac)? Aura (epilepsy)?
Witness history
Things to remember about elderly epilepsy
New epilepsy can occur e.g. 20% stroke pts withing a year.
Elderly are more susceptible to pharma causes.
Pallor suggests cardiac
Drowsiness suggests epilepsy.
Don’t forget to do an EEG if indicated, and check hypoglycaemia.
Investigations in blackout.
FBC, U&Es, glucose, TFTs, Ca++
ECG
24 hr ECG if indicated
EEG and/or CT scan.
Cardiac causes of blackout in elderly
Arrhythmias
MI (can be pain free)
Aortic stenosis (w SOBOE, syncope OE, angina)
Hypertrophic cardiomyopathy
Postural hypotension
Carotid sinus syndrome
VV syncope ( c. 2 mins, urinary incontinence uncommon but possible. Brief clonic jerking).
How is the Glasgow Coma Scale divided up?
E4, V5, M6
Key symptoms of meningitis
Fever, neck stiffness, photophobia, petechial rash.
A rare meningitis to keep in mind due to significant mortality
Listeria monocytogenes meningitis - more common in extremes of age, immunosuppressed, cancer, alcoholics, diabetics and liver/renal failure. Not treatable by cephalosporins, so use amoxicillin.
Meningitis caused by inhaled pigeon droppings.
Cryptococcus neoformans infection. Causes pneumonia, cutaneous infections and meningitis.
Diagnose using CT/MRI, india ink or CrAg.
Common causes of viral meningitis
Enterovirus (self-limiting)
HSV2 (IV aciclovir)
VZV and other herpes viruses (aciclovir)
Uncommon causes of viral meningitis
Mumps
Measles
LCMV (v. rare)
Presentation, diagnosis and treatment of viral meningitis caused by enteroviruses
Most original infections asymptomatic but may be associated with rash, pharyngitis, pericarditis and cardiomyopathy.
Neurovirulent strains EV70 and 71 may cause paralytic manifestations.
Use PCR on CSF
Often self-limiting
Presentation, diagnosis and treatment of viral meningitis caused by HSV2 (3% of viral meningitides)
Generally primary genital infection, someties reactivation from sensory nerve.
May have not peripheral skin lesions
Diagnosis is realtime PCR on CSF
Treat with IV aciclovir
RARE: meningitis caused by mumps - presentation and management.
Mild and selflimiting in 20% of cases of mumps, 0.1% develop severe encephalitis
Supportive management
RARE: meningitis caused by measles - presentation and management.
Acute encephalitis in 0.1% of cases, mortality 15%.
SSPE leads to CNS degeneration 8-10 years later.
Supportive management
People at risk of LCMV meningitis
Lab workers, pet owners and people living in unsalubrious places
CSF: normal appearance, polymorphs, bacteria, protein and glucose
clear, 50% of blood glucose.
CSF in acute bacterial infection
turbid, usually 500-10000 polymorphs, bacteria identifiable on gram stain unless treated, usually raised protein, low glucose.
CSF in viral infection
Usually clear, sometimes turbid, usually 50-1000 polymorphs, no bacteria, protein sometimes raised, normal glucose.
CSF in TB
often slightly turbid, occasionally with spider web clot. 50-1000 polymorphs, bacteria found with careful searching of auramine stained CSF, usually raised protein, low glucose.
presentation of brain abscess
Intracranial mass effects
Raised intracranial pressure
Causes of brain abscesses
Recent neurosurgery; commonly staph or throat/sinus flora.
Local parameningeal infections; abscesses occure in adjacent areas of brain from infected area. Mucosal anaerobes, oral strep, coliforms.
Distant infection with haematogenous spread; lung abscess, empyema, neglected appendicitis and endocarditis etc (anaerobes, strep)
Cranial trauma: skin or mucosal flora commonly.
What increases risk of brain abscesses
Right to left congenital heart shunt.
Recent neurosurgery
Local parameningeal infections.
What is the TB stain?
Rapid: auramine stain
Confirmation: Z-N stain
PCR if smear positive.
Presentation of herpes encephalopathy
Altered consciousness, confusion, seizures, possible fever, usuallly in the elderly. Fatal untreated.
Major cause of herpes encephalopathy
HSV1
Arbovirus encephalopathies
Often self-limiting. Diagnosis by CSF and blood ELISA and PCR.
Rabies encephalopathy
Tingling at wound site, fever, headache and malaise. Progresses to hallucinations, hydrophobia, maniacal behaviour, paralysis, coma and death.
Causes of hypoglycaemic coma
Plasma glucose typically lower than 3.0 mmol/L
Caused by insulin, or rarely liver disease, glycogen storage disease, addison’s, post gastric surgery, insulinoma. Patients with DM1/2 who have taken alcohol.
Presentation of hypoglycaemic coma
Sweating, anxiety, hunger, coma, fits, focal neurology.
Causes of diabetic ketoacidosis
Decompensated DM1. Omission of insulin or undiagnosised.
Insulinopenic state → hyperglycaemia, acidosis, ketone presence in plasma/urine
Cause of Wernicke’s encephalopathy
Thiamine deficiency - alcoholism or complication of bariatric surgery.
Treatment is thiamine.
Signs and symptoms of Wernicke’s encephalopathy.
Confusion, dementia, ataxia, nystagmus, opthalmalplegia and coma.
Petechial haemorrhages in mammillary bodies, dorsal brain stem structures affected.
Investigations for Wernicke’s encephalopathy
FBC: low platelets, high mean corpuscular volume (chronic ethanol ingestion)
slightly low phosphate (malnutrition)
slightly high bilirubin
High serum ethanol
Hepatic encephalopathy - cause.
Hepatic dysfunction
Hepatic encephalopathy - signs and symptoms
Confusion, reduced consciousness.
Stigmata of chronic liver disease
Investigations show reduced hepatic synthetic function and elevated plasma ammonia.
Ethanol toxicity
Disinhibition, ataxia, and reduction in consciousness.
Methanol toxicity - signs and symtoms
Metabolic acidosis, optic nerve toxicity.
Clinical suspicion, osmolar gap and plasma methanol.
What are the causes and results of ethylene glycol toxicity?
Ethylene glycol toxicity is caused by ingesting anti-freeze.
Initially similar to ethanol toxicity, leading to metabolic acidosis, cardiovascular issues and acute renal failure.
What do urea cycle defects lead to?
High ammonia.
Anion gap calculation
[cations] - [anions]
Normal anion gap acidosis is caused by
Bicarbonate loss or H+ ingestion as ammonium chloride.
Increased anion gap acidosis causes
Uraemia, ketoacidosis, lactate acidosis and salycylate poisoning.
Which spinal tracts carry pain sensation?
Lateral thalamic tracts to somatosensory cortex.
If disturbed sleep is associated with pain, what does this mean?
If there is peripheral pathology, this is a red flag. If it is central, sleep is always disturbed.
What are the red flags for any peripheral pain?
Disturbed sleep, Systemic upset, weight loss, night sweats, inflammatory pain.
35-50% of all blackouts in the elderly are caused by…?
Vascular disease
Causes of bacterial meningitis in young babies
Group B Streptococcus (most common cause in neonates)
E. coli
Listeria monocytogenes
Causes of bacterial meningitis in 3 months - 6 years
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
Causes of bacterial meningitis in 6 years to 60 years
Neisseria meningitidis
Streptococcus pneumoniae
Causes of bacterial meningitis in over 60s
Streptococcus pneumoniae
Neisseria meningitidis
Listeria monocytogenes
