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