CNS Head & Neck Flashcards
Acute disseminated encephalomyelitis. (ADEM)
Acute demyelinating disease that occurs after recent viral infection or vaccination. - Autoimmune - Predominalty children.
10-20% mortablity but early identification and Tx with steroids allows full recovery. If not treated can lead to Acute haemorrhagic leukoencephalitis which is fatal.
Imgaging:
Multiple T2 WML. Brain stem, Deep grey matter nucleu s, cerebellum and GWJ can be involved.
Adenoid cystic carcinoma
Presentation
- Slow growing tumour in the salivary galnds>parotid.
- Perineural spread with paralysis of the recurrent laryngeal nerve
Alzheimers
SPECT: Decreased HMPAO perfusion in temperoparieal regions.
FDG PET: Hypometabolism in parietal and medial temporal lobes. - late disease = frontal lobe and preservation of the sensorimotor strip.
Ameloblastoma (adamantinoma)
Lucent jaw lesion that can erode teeth.
Soap bubble appearance with cortical destruction.
Multilocular with fluid/fluid levels on MR.
Anaplastic thyroid cancer
Uncommon
Old ladies and post radiation
Rapid growth with primary lympahtic spread.
Does not respond to I-131
Antrochoanal polyp
Teenagers and young adults.
Weel defined mass extending from maxillary sinus to nasal cavity. Dunbell shaped. Expands the maxillary ostium.
Bacterial meningitis
Organisms:
Group B Strep and E. Coli - Neonates
Citrobacter - Premature new borns
H. Influenzae - Children
N. Meningitidis - Teenagers
Strep. Pneumoniae - Adults
Bells Palsy
HSV inflammation of the peripheral facial nerve.
MRI:
Enhancement of the intracanilcular and labyrinthine segements which do not normally enhance.
Branchial cleft cyst
1st - EAC ( periauricular) or parotid
2nd - most common - anterior border of SCM from tonsillar fossa to carotid bifurcation.
3rd - (rare) posterior cervical space or low anterior border of SCM.
4th - (rare) from priform fossa to crycothroid joint.
CADASIL
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.
Young patients with recurrent TIA/strokes, seizures and psychiatric symptoms.
MRI - bilateral symmetrical high T2 hyperintensities in external capsule, periventricular and temporal regions.
Causes of pulsatile tinnitus
Normal vascular variants
- Aberrant ICA
- Jugular bulb anomalies (high, dehiscent or diverticulum)
- Persistent stapedial artery.
Tumours
- glomus jugulare or glomus tympanicum
Vascular abnormalites - AVM, atherosclerosis, carotid-carvernous fistula, FMD etc.
Other - IIH, Pagets, Otoscelrosis and Meniere disease.
Central neurocytoma
- 20-40yo
- Px with signs and symptoms of hydrocephalus.
- Globular lesion attached to septum pellucidum. Iso to brain, 50% show calcification and dense contrast enhancement.
Chiari malformation
Chiari I:
- Downward displacement of the cerebellar tonsils with elongated 4th ventricle.
- Assoc with Klippel-Feil.
- Syringohydromeyelia
Chiari II:
- Small posterior fossa
- Herniation of the cerebellar tonsils, vermis and caudual displacementof the brainstem.
- Assoc w/ myelomenigocele, obstructive hydrocephalus and dysgenesis o the corpus collosum.
Cholesteatoma
Aquired:
- most common - 98%
- arise from Prussak’s space (antero-superior) - pars flaccida cholesteatoma
- displaces ossicles medially and erodes lateral structures.
- errodes head of malleus and long process of incus.
- arise from sinus tympani (postero-superior) - pars tensa
- displaces ossicles laterally
- erodes shor process f incus and stapes.
Congenital:
- 2% - epidermoid - arise from middel ear, EAC, mastoid, petrous and labyrinth.
MRI - restricted diffusion and no enhancement.
Cholesterol granuloma.
Mix of haemorrhage, cholesterol crystals and granulation tissue.
expansile errosive lesion with smooth edges arising from the pertous apex.
MR - T1 bright ofn MR due to mHb and cholesterol. Does not fat supress.
CT - iso dense to brain and does not enhance.
Choroid plexus papilloma / carcinoma
Adults:
4th ventricle
Children:
Trigone
- Enhance
- Calcify
- Secretes CSF (hydrocephalus)
CJD
Classic:
- Older Adults
- Progressive dementia (4-5 m)
- DWI and T2/FLAIR in caudate, putamen and GM.
Variant:
- Young adults (20-30)
- psychiatric and behavioral symptoms over a year.
- Pulvinar (Hockey stick) sign - T2/FLAIR in posteromedial thalamus.
Cleidocranial dysostosis
Hypoplastic, malformed or absent clavicles
Large head
Underdeveloped facial bones
CNS Herpes simplex virus.
Most common cause of viral encephalitis.
HSV2 - Neonatal transmission from mother via vaginal delivery.
HSV1 - Usually reactivation of latent infection. Commonly effects the trigeminal nerve.
Presentation: Herpes eephalitis. Seizure and coma with CLASSIC EEG finding = ‘Localised spike and slow wave pattern’ in temporal lobes.
Dx and Mx: Early acyclovir and CSF PCR confirm Dx and reduce mortality. (Up 70% if untreated)
Imaging:
MR show gyriform high T2 and FLAIR in temporal lobes. May effect the cingulate gyrus and frontal lobes. +/- diffusion restriction.
CNS imaging manifistation of Wilson’s disease
Disorder of copper metabolism.
MRI - 1. white matter atrophy.
- T2 hyperintensities affecting the basal ganglia and thalami.
CNS mets
Intra-axial:
Lung, Breast, Melanoma, Colon
Extra-axial:
Breast, Lymphoma, Prostate, Lung and neuroblastoma.
Most are suprartentoral apart from RCC (Posterior cranial fossa.
Haemorrhagic :
Melanoma, Thyroid and Renal.
CNS Varicella Zoster Virus
Presentation can be similar to HSV encephalitis. Typically follow an ilness with a skin rash.
Can cause herpes zoster opthalmicus = Compilcated ipsilateral cerebral angiitis causing cerebral infarction and contralateral hemiparesis. Angiography shows beading of medium/large arteries +/- Mycotic aneurysms.
Cranial nerve neuritis = commonly VII and VIII = Ramsay Hunt syndrome = ear pain + facial paralysis + vsicular eruption about the ear. MRI shows abnormal enhancement of these nerves.
Coats disease
Exudative retinopathy. -lipoprotein accumulation and telangiectasia leading to retinal detachment.
Predominatly unilateral. Occurs in 1st decade of life.
MR: T1 and T2 hyper. calcification is rare.
Congenital CMV
Caused by reactivation or primary maternal infection
Spread transplacentally or in breast milk
Symptoms:
Hepatomsplenomegaly, Jaundice, Psychomotor retardation, Deafness
Imaging:
- Periventricular calcifications.
- Ventrculomegaly and polymicrogyria
- Agyria, cortical dysplasia and heterotopia (if infection in first trimester- disruption of neuronal migration)
Congenital CNS Rubella
Transplacental spread
Causes diffise microencephalitis, brain infarction and necrosis.
Presentation - microcephaly, ocular abnormalities and deafness.
Imaging:
CT - dytrophic calcifications of deep grey nuclei.
MRI - Infarcts, WM volume loss, delayed myelination
Congenital HIV
Transplacental or breast feeding spread/
Present with encephalopathy, developmental delay, and failure to thrive.
Imaging:
Affects white matter resulting diffuse cerebral volume loss.
- CT - symmetric calcifications of BG (GP)
- MRI - WM T2 hyperintensities
- MRA - fusiform ectasia of arteries
Congenital HSV
Encephalitis following infection during descent from the birth canal when mother has HSV2.
Diffuse encephalitis with infarction. Fatal-severe.
Presents with fever, rash, lethargy and seizures in the first few weeks of life.
CSF: pleocytosis, Increased protein and decreased glucose.
Imaging:
- Cystic encephalomalacia
- Enlarged ventricles.
- Diffuse brain swelling
- Multiple low densities/high T2 sparing the BG, thalami and posterior cranial fossa structires.
Congenital Toxoplasmosis
Necrotising encephalitis of the fetal brain following haematogenous spread from mother.
Destruction occurs during 2-3rd trimester.
Born with microcephaly, chorioretinitis and mental retardation.
Imaging:
- Atrophy and dilatied ventricles.
- Dystrophic calcifications scattered throughout the white matter, basal ganglia and cortex.
Congential CNS infections
TORCH
Toxoplasmosis
Other - Syphilis and variccella
Rubella
Cytomegalovirus
Herpes and HIV
Corticobasal degeneration.
50-70yo.
motor, sensory and cognitive symptoms.
Parkinsonism, non-fluent apphasia and alien limb phenomenon.
MRI:
- Asymetric volume loss in the perirolandic cortex.
- Patchy T2/FLAIR hyperintensity in subcortical WM of the pre- and post-central gyri.
Cowden Syndrome
- Hamartomas (Brain = Lhemitte-Dulcos)
- Breast Ca
- Thryroid Ca
Craniopharygioma
Sellar mass.
- Childhood calcifies
- Adult solid tumour
Creutzfeldt-Jakob Disease (CJD)
Prion disease - uniformly fatal rapidly progressing neurodegenrative disorder.
Sporadic type = elderly worldwide
Iatrogenic type = post surgery.
New variant type = meat from infected cows. Young.
Presentation: Variable neurological signs, rapidly progressive dementia with myoclonic jerks and akinetic mutism.
80% mortality in first year.
CLASSIC EEG = period of shape waves
Imaging:
- FLAIR and T2 high in caduate and putamen. Ribbon like hyperintensities around scattered around the cortex.
- nv CJD - medial thalami ‘hockeystick’ T2 hyperintesities.
CT features of hyperaemia?
- Ill-defined mass effect.
- Effacement of sulci
- Normal attenuation of brain.
Cysticercosis
Tenia solium. Faeco-oral from pig faeces.
Humans intermediate hosts.
Present with headaches and seizures.
Dx: CSF serology.
Imaging:
- Early = Minimal oedema with nodular enhancement.
- Vesiucular stage = viable paracytic cysts at GWJ. (1cm or less) Hypodense on CT and iso to CSF on MR. +/-scolex.
- Colloid stage = dead cyst and fluid leaks causing inflammation. Ring enhancement with vasogenic oedema = encephalitis. The cust beome dense on CT and hyper intense to CSF on MR.
- Nodular granular stage = smaller cyst. with increasing nodular peripheral enhancement.
- nodular calcified stage.
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Desmoplastic Infantile Ganglioglioma
- RARE - fist year of life.
- Large peripheral heterogenous mass (solid / cystic)
- M:F = 2:1
- Presentation: Rapidly expanding head circumference.
DNET ( Dysembryoplastic Neuroepithelial Tumour)
- Kid with epilepy (refractory complex partial seizures)
- 10-30 yrs
- CORTICALLY BASED in the temporal lobe
- Bubbly T2 lesion - no oedema
- Low grade
Echinococcosis (Hydatid Disease)
Dog tape worm. People from non-industrialised world countries.
Lungs, liver and brain.
Present with raised intracranial pressure symptoms.
Large, round, smooth, uni-or multilocular cysts.
Facial nerve
Four parts:
- Intraxial
- Cisternal segment
- Intrastemporal segment
- meatal IAC - anterior superior (7 up)
- labyrinthine
- tympanic (horizontal) - gives off greater petrosal nerve.
- mastoid (vertical) - gives off nerve to stapedius and chorda tympami.
- Extracranial
- Exits stylomastoid foramen immediatly giving off the posterior auricular nerve
- The splits in the parotid giving off 5 branches.
Follicular thyroid cancer
Second most common thyroid ca.
Mets haematogenously - bones, lungs, liver…
Does not respond to I-131
Fungal meningitis
Thick meningeal enhancement of the basal cisterns. Similar to TB.
Gangliogioma
- Presents - Kid with seizures.
- M>F and under 30
- Most common tumor in chronic tempral lobe epilepsy.
- Cortically based.
- Temporal lobe>anywhere>spinal cord.
- Cyst with an enhancing nodule
- Low grade
Glioblasoma Multiforme
- Most malignant form of astrocytoma.
- Peak age 45-55
- M>F
- Frontal>Temporal>Basal Ganglia
Imaging:
- Expansile Mass
- Central necrosis
- Ring enhancement
- Vasogenic oedema
MRI:
- T1 Dark T2 Bright
- Cystic
- Flow voids
Gliomatosis Cerebri
- Rare neuroepithelial neoplasm
- Widespread infiltration of neoplastic cells.
- At least 3 lobes have to be affected.
- Mild clinical symptoms.
- Peak incidence 40-50.
MRI:
- T1 Dark and T2 bright diffuse white matter and grey matter.
- Centrum semiovale, hypothalamus, thalamus and basal ganglia.
- Loss of grey/white matter differentiation with little mass effect.
Glomus tumours (distribition)
Tympanicum - cochlear promontary - commonest tumour to casue tinnitis
Jugulare - jugular foramen (JF) - causes permeative bone changes in JF and has characteristic S&P T2 MR appearance due to flow voids - most common GT overall.
Vagale - vagus nerve in the nasopharangeal carotid space DISPLACES THE CAROTID ANTEROMEDIALLY AND THE JUGULAR VEIN POSTEROLATERALLY.
Carotid body - SPLAYS THE ECA AND ICA
Gradenigo syndrome
- Otitis media 2. Retro-orbital pain 3. Abducens nerve palsy. Results from abscess in petrous apex. Causes pseudomonas or enterococcus
Hallervorden-Spatz
Pantothenate kinase-associated neurodegeneration (PKAN)
Extrapyramidal and pyramidal signs
Iron accumilation on the globus pallidi and brain stem nuclei.
Low T2 GP and T2* in areas of iron accumilation.
‘eye of the tiger’ sign.
HIV encephalopathy
AIDS
Vacuolation of white matter with demyelination and multinucleated giant cells.
Centrum semiovale > brain stem > cerebellum. (spares subcortical U fibres)
Present with subcortical dementia, cognitive, behavioral and motor decline.
Predominantly WM atrophy.
Imaging:
MR Deep WM/periventricular symmetrical hazy highT2 - No contrast enhancement.
Huntington’s disease.
- Atophy of the heads of the caudate nuclei and consequential ‘box like’ prominence of the frontal horns.
- PET - low activity in caudate and putamen.