Neuro quickfire Flashcards
Listeria meningitis
a) Risk factors
b) Presentation
c) CSF results
d) Management
a) Newborns, elderly, alcoholics, diabetics, immunosuppressed
- Contaminated/undercooked food (e.g. pate, unpasteurised cheese)
b) Acute meningism +/- brainstem/cerebellar signs
c) As for bacterial meningitis: low glucose, raised protein, may have predominantly PML or lymphocytes
d) Ampicillin/amoxicillin
(note: cephalosporins do NOT work against listeria)
Cavernous sinus
a) Structures within
b) Structures superior
c) Structures inferior
a) CN III, CN IV, CN V1, V2, CN VI, ICA, sympathetic nerves
b) Pituitary gland, optic chiasm
c) Sphenoid sinus, sphenoid bone
CSF findings:
- GBS
- MS
- Bacterial meningitis
- Viral meningitis
- Fungal meningitis
- TB meningitis
- Malignancy
- GBS: elevated protein, normal cell counts, (may have oligoclonal bands)
- MS: normal protein, normal cell counts, oligoclonal bands
- Bacterial meningitis: turbid, very raised opening pressure*, low glucose, raised protein, PMN cells
- Viral meningitis: clear, slightly raised opening pressure, normal glucose, raised protein, lymphocytosis
- Fungal meningitis: clear, raised opening pressure (as often have hydrocephalus), low-normal glucose, normal-high protein, lymphocytes. Use India Ink stain
- TB meningitis: clear, raised opening pressure, low glucose, raised protein, lymphocytes. Use ZN stain
- Malignancy: low-normal glucose, raised protein, high lymphocytes, malignant cells (though may not be found on initial sample)
*Normal opening pressure <25 cm H2O,
Bacterial meningitis often 50-80 cm H2O
TB vs. cryptococcal meningitis
a) LP findings
b) Clinical features
c) MRI findings*
d) Treatment
*Note - CMV meningoencephalitis (found in AIDS) has ependymal enhancement on MRI.
TB meningitis:
- Raised opening pressure (~30), low glucose, raised protein, lymphocytosis
- Subacute presentation of meningism
- Multiple cranial nerve palsies
- CSF should be stained with Ziehl-Nielsen to look for mycobacteria
- MRI: basal enhancement
- Rx: 2 months of RIPE (+ pyridoxine) followed by 10 months* of rifampicin + isoniazid (+ pyridoxine)
*as opposed to 4 months of rifampicin/isoniazid in non-CNS TB
Cryptococcal meningitis:
- Subacute meningism
- CN VI palsy (false localising sign), but multiple CN palsies are rare
- India ink test used
- LP as for TB, but with a higher opening pressure (>40)
- MRI: leptomeningeal enhancement
- Rx: 2 weeks of IV amphotericin B + flucytosine
False localising signs
- Meaning
- Generally caused by…?
- Most common example
- Example common with uncal herniation
False localising signs are ones that lead to breakdown of the clinico-anatomical method of localisation. They often occur as a result of raised ICP
- Most commonly, CN VI (abducens) palsy, which may be unilateral or bilateral. It is thought to be particularly sensitive due to either it’s long course along the petrous part of the temporal bone, or because it comes straight forward from the brainstem is more vulnerable to strain during posterior movement of the brainstem in raised ICP (e.g. IIH may have unilateral or bilateral CN VI palsy)
- Ipsilateral CN III palsy (first sign is Hutchinson pupil - mydriasis without ophthalmoplegia)
- Contralateral hemiparesis due to pressure on the crus cerebri in the midbrain (prior to decussation)
- Kernohan phenomenon -ipsilateral hemiparesis due to downward movement of the contralateral tentorium cerebelli, which causes compression of the contralateral crus cerebri
Chiari malformations
a) Types 1-4
b) Which is associated with (i) syringomyelia, ii) myelomeningocele
c) Presentation
d) Treatment
e) Differentiation from foramen magnum meningioma
f) How does syringomyelia usually present?
a) All Chiari malformations involve herniation of part of the brain into foramen magnum:
- Type 1 = herniation of cerebellar tonsils, may only present later in life
- Type 2 = associated with myelomeningocele (often paralysed below opening)
- Type 3 = cerebellum/brain herniation, often associated with profound neurological abnormality - seizures, learning disability, etc.
- Type 4 = cerebellar hypoplasia
b) - Type 1,
- Type 2
c) Type 1 may present with syringomyelia (cape like distribution, pain & temperature loss first - scalding burns), also difficulty walking DOWN stairs, features of raised ICP, cerebellar signs (ataxia, nystagmus)
d) Treatment:
- Decompressive surgery - posterior fossa decompression
- Hydrocephalus management e.g. VP shunts
e) Foramen magnum meningioma likely causes corticospinal involvement (limb weakness, UMN signs)
f) - Usually in age 20-30s
- Pain in the neck/upper limbs worse on coughing
- Loss of pain/temp sensation
- Progresses to involve dorsal columns and corticospinal tracts
Cerebellopontine angle syndrome
a) Which is the first nerve to be affected after vestibulocochlear?
b) Appearance of acoustic neuroma on CT scan
a) Trigeminal nerve (loss of corneal reflex). Facial nerve palsy presents later as more resistant to compression
b) “Trumpet” sign due to extension into internal acoustic meatus
Holmes-Adie syndrome
- 2 features
- causes
- what is Ross syndrome?
Features:
- Dilated pupil with sluggish reflexes to light and accommodation
- Sluggish deep tendon reflexes also
Cause: usually idiopathic, but could be trauma, inflammation, etc.
Ross syndrome:
- Adie syndrome + localised anhidrosis (may have compensatory hyperhidrosis elsewhere)
Numb chin syndrome
- what is it?
- causes
Reduced sensation on the chin (usually unilateral) due to mental nerve palsy
Causes
- dental infection/mass
- MS
- metastatic malignancy (thought to be due to ?mandibular mets)
Aseptic meningitis
- define
- causes
Aseptic meningitis involves elevated WCC (>5)* with a negative culture
Causes include:
- Partially treated bacterial meningitis** - may have more of a lymphocytes > neutrophils picture
- Viruses, fungi, TB
- Inflammatory - sarcoid, SLE, Behcets, GPA
- Neoplastic - metastatic, leukaemia/lymphoma
- Drug induced - NSAIDs, penicillins, IVIG
*Accept 1 WCC for every 1,000 RBCs
**e.g. on antibiotics for separate infection, or started ABx before LP carried out
Drugs contraindicated in MG:
(ABCPQ)
Antibiotics (gent, doxy, macrolides, cipro) and antipsychotics
Beta-blockers, NM blockers
Calcium-channel blockers
Penicillamine, procainamide
Quinidine
https://www.myaware.org/drugs-to-avoid
Paraneoplastic syndromes
a) Common types
b) Antibodies commonly found
a) - Peripheral neuropathy
- LEMS (SCLC), MG (thymoma)
- Cerebellar ataxia
- Optic neuritis
- Opsoclonus/myoclonus
- Encephalitis - limbic, encephalomyelitis
- Stiff person syndrome
b) - Anti-CRMP5
- Anti-CV2
- Hu
- Anti-NMDA
25 year old female, reduced visual acuity left eye with washed out colours. Reduced direct and consensual pupillary reflexes in the left eye. Optic discs appear normal on fundoscopy.
a) What is the diagnosis?
a) Retrobulbar neuritis
- Like optic neuritis but the inflammation is behind the optic discs, hence these will appear normal
- “The patient sees nothing, and the doctor sees nothing”
Meningitis contact management
Ciprofloxacin, or rifampicin
Antiepileptics
a) Topiramate - pros and cons
a) - Pros - good for the liver
- Cons - teratogenic, renal stones, AACG risk, paraesthesia
