Organic disorders Flashcards
Outline CJD variants?
Subtypes: familial (fCJD), iatrogenic (iCJD), sporadic (sCJD) and new variant (vCJD).
Variant CJD: young adults, onset 13-14 months, psychiatric presentation with behaviour symptoms, neuro signs (e.g. myoclonus) appear later, pulvinar sign on MRI (symmetrical hyperintensity of pulvinar, thalamic nuclei), can do tonsillar biopsy
Sporadic CJD: most common (85%), onset 5-6th decade, rapid onset 4-5 months, early dementia with neuro signs (myoclonus and ataxia), EEG synchronous triphasic, periodic, sharp-wave complexes at 1-2Hz (myoclonic jerks), MRI hyperintensity in caudate and putamen, 14-3-3 protein in CSF
Outline features of neurosyphilis?
Clinical:
- can be asymptomatic in early stages, no defined clinical signs
- Light reflex absent, accommodation reflex present
- Tabes dorsalis in 20%; demyelination of neural tracts of dorsal root ganglia of the spinal cord (nerve root), lancinating nerve root pain
- Can present with meningitis; fever, neck stiffness, delirium, polymorphs in CSF
Ix:
- Serology may be positive in blood and neg in CSF
- Definitive diagnosis of neurosyphilis is CSF for VDRL
What does bilateral foot drop suggest?
Indicates peripheral neuropathy, suggestive of alcoholism or neurosyphilis (tabes dorsalis)
What does horizontal nystagmus suggest?
Horizontal nystagmus: involvement of lateral rectus palsy, e.g. alcoholism
What is an ARP?
Argyll Robertson Pupil (ARP) ; small pupil, irregular outline, reacts to convergence (accommodation) but not to all light (no light reflex)
Classically seen in neurosyphilis
What is tabes dorsalis?
Tabes dorsalis: degeneration of ascending fibres of dorsal root ganglia. Causes pain (lighting, stabbing), paresthesia and gait disturbance.
Seen in neurosyphilis
Differentiate between Kernig and Brudsinski’s signs?
Kernig’s sign: patient supine, dorsiflex at hip and then straighten legs. Pain in neck and back.
Brudzinski’s sign: touch chin to chest. Pain in neck and dorsiflexion of legs at hips in severe cases.
Implications of hypercalcaemia?
- can occur in parathyroid abnormality (hypoparathyroid causes low Ca)
- parathyroid abnormality can occur with lithium administration
- sarcoidosis
- paraneoplastic syndromes
Implications of hyperparathyroidism?
Mnemonic: bones, stones, abdo groans and psychic moans
Lithium can cause hyperparathyroidism
Outline the features of Wernicke’s encephalopathy?
Clinical triad: nystagmus (ophthalmoplegia), ataxia, confusion
- horizontal nystagmus (lat rectus palsi, CN6)
Occurs in thiamine (B12) deficiency, ETOH
Thiamine dosing: 200-300mg IM, oral absorption may be insufficient to prevent progression to Korsakoff psychosis
Path: mamillary body swelling
Outline features of Korsakoff psychosis?
Clinical: anterograde (most common), retrograde amnesia, confabulation
Path: mamillary body necrosis
Outline the features of SIADH?
Syndrome of Inappropriate ADH Secretion (SIADH)
Clinical: hyponatraemia (<135mmol/L), hypo-osmolality (>280mOsm/kg), urine concentrated (increased urine osmolality)
Path: Anti-diuretic hormone causes body to retain water
Aetiology: all psychotropics, esp antidepressants in >65yo
Note: in risk of SIADH (e.g. on diuretics), use agomelatine or mirtazapine
Outline the features of hyponatraemia?
Hyponatraemia: confusion, ataxia, delirium, muscle weakness, myoclonus tremor, seizures, tremor
Outline features of psychogenic polydipsia?
Clinical: hyponatraemia, low/normal osmolality, dilute urine (low urine osmolality)
Outline features of serotonin syndrome?
Clinical: myoclonus, hyperreflexia, confusion, delirium
Causes: serotonergic antidepressants
Outline features of NMS?
Neuroleptic Malignant Syndrome (NMS)
Path: acute, sudden dopamine blockade due to high potency antipsychotics or high dosage
Clinical: rigidity, fever, autonomic dysfunction (postural hypotension, fluctuating BP), raised CK, leukocytosis
Rx: bromocriptine (D2 agonist), dantrolene (muscle relaxant)
Outline features of discontinuation syndrome?
Clinical: electric shock sensations “brain zaps”
Outline features of neuropsychiatric SLE?
Clinical: malar rash, cytopenia (neutropenia, lymphopenia), alopecia, arthritis
- depression, cognitive issues, headache
Ix: ANA, anti-dsDNA, anti-ENA
Outline features of Addison’s disease?
Path: mineralocorticoid insufficiency
Clinical: hyperkalaemia, hypernatraemia, fatigue, lethargy, hyperpigmentation of mucus membranes (buccal mucosa), vitiligo, low mood
Ix: synacthen test (synthetic ACT does not result in adrenal secretion of mineralocorticoids)
- adrenocorticotropic (ACT) hormone released by pituitary and adrenals ordinarlity secrete mineralocorticoids
Outline features of Cushing’s disease?
Clinical: weight gain, HTN, hirsutism, moonface, Buffalo Hump
- irritability, poor STM, poor concentration, fatigue
Ix: dexamethasone suppression test (dexamethasone should suppress cortisol release but this does not occur)
What is senile chorea?
Slowly progressive, generalised chorea in elderly people without mental deterioration or a clear underlying cause
Clinical: bradykinesia, gradual onset of generalised and symmetrical chorea, slow onset, not mental/emotional disturbance
DDx: Huntington’s (must exclude)
Note: no family hx of movement disorders
Outline features of Parkinson’s disease?
Clinical: bradykinesia, low frequecy tremor, stiffness, shuffling gait, festination marche a petit pas (small step marching), poor turning, blunted affect, micrographia, hypomimia (mask facies), hyophonia, decreased blink rate, REM sleep movement disorder (loss of atonia in REM), dysarthria
- 4 cardinal signs: asymmetric resting tremor, rigidity, bradykinesia, postural instability
Path: loss of pigmented dopaminergic neurons in pars compacta (substantia nigra) and Lewy Bodies
Rx: Levodopa and carbidopa (peripheral decarboxylase inhibitor, prohibiting the decarboxylation of levodopa to dopamine, allowing more levodopa to enter CNS), selegiline (MAOB), pramipexole (dopamine agonist), benztropine (anticholinergic, increasing availability of dopamine)
What does hemiballismus suggest?
Clinical: unilateral swinging movements
Path: subthalamic nucleus of basal ganglia
Outline pathology of Huntingon’s chorea?
Pathology: The principal pathology is the loss of striatal and cortical projection neurons. Changes in brain DA content and receptor number contribute to abnormal movements and cognitive deficits in HD.
- In particular, during the early hyperkinetic stage of HD, DA levels are increased whereas expression of DA receptors is reduced.
- In contrast, in the late akinetic stage, DA levels are significantly decreased and resemble those of a Parkinsonian state.
Outline the genetics of Huntington’s disease?
- autosomal dominant, 100% inheritance
- caused by the expansion of a trinucleotide repeat beyond 35 repeats in huntington gene located in the short arm of chromosome 4. Severity depends on number of repeats.
Outline the investigations and treatment for Huntington’s disease?
Imaging: SPECT or PET
- SPECT (most appropriate Ix): will demonstrate caudate and putamen hypermetabolism
- MRI: caudate and putamen atrophy seen later in disease progression
Treatment: tetrabenazine (dopamine depleter)
Outline the features of NPH?
Normal Pressure Hydrocephalus (NPH)
- DDx: dementia
- Features triad: dementia, ataxia, urinary incontinence
- Treatment: surgical shunt
Discuss supranuclear palsy?
Aetiology: tauopathy, form of fronto-temporal dementia
Clinical features of FTD: rigidity, bradykinesia, vertical gaze palsy , postural instability, early falls, also changes in personality
- Vertical gaze palsy presents as falls whilst climbing up or down stairs, or diplopia on vertical gaze
Pathology: neurofibrillary tangles in basal ganglia and brain stem
Outline the features of a prolactinoma?
Features: hyperprolactinaemia (serum prolactin >5000), galactorrhoea, headache, homonymous hemianopia
Imaging: MRI sella turcica
- Sella turcica is a midline, dural lined structure in the sphenoid bone, which houses the pituitary gland
Outline the features of MS?
Clinical: young female, eye involvement or bladder involvement, depression, L’hermittes signs (neck movement results in electric shock sensation down the back)
Imaging: MRI T2 weighted or T2 FLAIR
- hyperintense lesions (sclerotic plaques)
