Justifying an organic differential
diagnosis
John O’Donovan
True story about one of my friends
doing MRCPsych Part 2
• “What’s your differential?”
• “Oh, schizophrenia, schizoaffective disorder,
mood disorder and of course organic”
• “Which particular organic process?”
• “oh you know, all of them potentially”
• “No, I don’t know, which ones specifically”
• “oh you know, strokes and stuff like that..”
• At this point the conversation became very
unpleasant and remained so thereafter.
• She failed.
Basic rules
• Differential diagnostic lists should by
definition be brief.
• Offering an organic option is in fact stating
that there is an underlying brain disorder or
systemic disorder causing the presentation
• If this is patently not the case, then do not
offer an organic differential
ICD-10
• F00 alzheimer’s
• F01 vascular dementia
• F02 dementia in other diseases-Pick’s, CJD, HIV,
Parkinson’s (note Lewy Body Disease is not there and
neither are the FTDs properly)
• F03 unspecified dementia
• F04 organic amnesic syndrome
• F05 delirium note both F04 and F05 exclude alcohol
and other addictive substances
• F06 organic brain disorders due to physical disease
• F07 organic personality disorders
ICD 10
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F06 Other mental disorders due to brain damage and dysfunction and to physical disease
F06.0 Organic hallucinosis
F06.1 Organic catatonic disorder
F06.2 Organic delusional [schizophrenia-like] disorder
F06.3 Organic mood [affective] disorder .30 Organic manic disorder
.31 Organic bipolar disorder
.32 Organic depressive disorder
.33 Organic mixed affective disorder
F06.4 Organic anxiety disorder
F06.5 Organic dissociative disorder
F06.6 Organic emotionally labile [asthenic] disorder F06.7 Mild cognitive disorder
.70 Not associated with a physical disorder
.71 Associated with a physical disorder
F06.8 Other specified mental disorders due to brain damage and dysfunction and to physical disease
F06.9 Unspecified mental disorder due to brain damage and dysfunction and to physical disease
F07 Personality and behavioural disorders due to brain disease, damage and dysfunction
F07.0 Organic personality disorder
F07.1 Postencephalitic syndrome
F07.2 Postconcussional syndrome
F07.8 Other organic personality and behavioural disorders due to brain disease, damage and dysfunction
F07.9 Unspecified mental disorder due to brain disease, damage and dysfunction
F09 Unspecified organic or symptomatic mental disorder
What about the other areas?
• F10-F19, addictions, NB withdrawal states are
coded here.
• F10.6: amnesic syndrome secondary to
alcohol.
• Therefore alcohol related brain damage goes
into the alcohol block, not the organic block,
although clearly there is an organic basis
The organic differential
• What suggests it?
• Atypical features of a psychiatric presentation
• Wrong age, wrong psychopathology, wrong
course, very much a gestalt phenomena
• Evidence of cognitive impairment,
neurological signs or systemic illness of some
type
Primary CNS versus Systemic
CNS
• Cognitive problems
• Seizures
• Headache
• Focal signs
• Remember blood brain
barrier, primary CNS
pathology, often does not
cause any systemic
abnormalities
Systemic affecting CNS
• Systemic markers
• General ill health
• Systemic questions
• Evidence of systemic
disease
Rare versus Common and causality
Rare illnesses
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Mitochondrial disorders
Autoimmune encephalitis
Paraneoplastic syndromes
Primary or secondary CNS
vasculitis
• Metabolic disorders, Niemann
Pick, metachromatic
leucodystrophy and other
leucodystrophies
• Wilson’s
• Many others
Common
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Stroke
Epilepsy
Multiple sclerosis
Dementias particularly
Alzheimer’s disease
Primary brain tumors are rare
HIV in the right setting
Huntington’s
Parkinson’s/LBD
Think
• Do you believe it?
• Have you ever seen it?
• Schizophrenia is not an uncommon illness and
neither is BPAD or recurrent depression.
• An uncommon presentation of a common
illness is always more common than a
common presentation of an uncommon illness.
CLINICAL SCENARIOS 1
• 24 year old female medical student who presents
to her GP with severe anxiety, weight loss of one
stone and mild tachycardia.
• Can’t sleep very well, palpitations, just broken up
with boyfriend.
• MSE: well groomed, thin, sweaty, cognitively
intact, intermittently tearful and crying, not
hallucinating or deluded.
• Physical exam: normal but pulse consistently 115
Grave’s Disease
Autoimmune
Far more common in
women
Insidious onset
Goitre, exopthalmos and
pretibial myxedema
Not all that uncommon
and is definitely associated
with anxiety and panic as
well as low mood.
Inv: TFTs, and thyroid
stimulating autoantibodies
Clinical scenario 2
• 44 year old man with 18 month history of
difficult to treat depression and severe
psychomotor retardation, complaining of a
painful right arm and being restless in bed at
night.
• MSE: depressed with negative cognitions,
retarded, cognitively normal.
• Physical: nil obvious
• Bloods normal, CT and MRI normal
Parkinson’s Disease
50% of PD patients at
onset of illness have a
severe depressive episode
Frequently does not
respond well to standard
ADTs
When someone is
depressed, mid life onset
of depression, particularly
if associated with
movement problems, then
consider
Clinical scenario 3
• 18 year old girl, presents with UTI in A/E having
“pseudoseizures”
• No prior history, brother has epilepsy.
• On IV antibiotics, C/O severe abdominal and loin pain
• Basic bloods normal
• MSE: orientated, C/O tummy pain, unusual affect labile
and tearful
• Collateral: family describe her as moody and difficult.
• CT brain done reluctantly in A/E is normal
Acute intermittent
porphyria
Acute attacks of abdominal
pain, seizures and central
disturbance. In particular
cognition and mood.
Diagnosis: biochemical
urine and blood
porphyrins.
That girl was real and she
died.
Clinical scenario 4
• 28 year old man brought in by police from the
street on a section as he was walking naked in
traffic. In A/E singing loudly, walking around and
irritable.
• MSE: accelerated and aggressive, elated mood,
sexually suggestive to nurses
• Collateral: normally well, good job, long term
history of epilepsy which is well controlled,
mother attends service with bipolar and is on
lithium. No recent seizures.
BPAD
Very little convincing
evidence that this man has
anything but bipolar
disorder with first
presentation of a manic
episode.
Clinical scenario 5
• 29 year old woman with MCTD on her
honeymoon in Australia. Begins to fight with
husband in hotel at Ayer’s rock. GP goes out, It’s a
domestic and legs it. Continues to be unwell for
next three weeks, ultimately seen in Sydney and
started on olanzapine.
• MSE: giggling, imprecisely orientated, Raynaud’s
phenomena, mild alopecia.
• Bloods ESR elevated, creatinine 180, anaemic,
dsDNA positive
SLE
Can cause anything
Vasculitis
White matter disease
All known psychiatric
presentations have been
reported in
neuropsychiatric lupus
Should have evidence of
systemic disease,
inflamatory response and
autoantibodies.
Clinical scenario 6
• 65 year old man, referred by GP with depression,
12 month history of sleep disturbance, complex
visual hallucinations at night and restless legs,
took overdose, wife notes that he is getting his
words mixed up, not obvious on exam,
complaining of problems with vision, not being
fixed with new glasses, can’t see TV properly,
treated with ADT starts to improve, then
develops headache and scalp tenderness
• Diagnostic test performed
Glioblastoma
Non dominant parietal and
temporal lobe
glioblastoma
Clinical scenario 7
• 22 year old single woman. Presents with
emotional lability, gross ataxia, supranuclear
gaze palsy and massive splenomegaly.
• Family history of a rare metabolic disease
already known.
Adult Niemann Pick
Disease
Rare metabolic disorder
which results in liver and
spleen disease and white
matter disorder in the
brain.
Incredibly rare, reason for
mentioning is that the
hereditary
leucodystrophies are
associated with psychiatric
presentations including
psychosis and depression.
They are not neurologically
normal.
Clinical scenario 8
• 60 year old woman with long standing
psychiatric history who presents with a manic
episode complicated by generalised seizures.
Get admitted under neurology, CT brain
normal, CSF raised protein and some white
cells, oligoclonal bands present, mild
hypothyroidism, unusually high titres of anti
thyroid antibodies
Hashimoto’s
encephalopathy
rare illness
Relapsing delirum like
picture but frequently with
lots of psychosis
Mechanism unknown but
does respond to steroids
and immunosurpression
Associated with high titres
of anti thyroid antibodies
Clinical scenario 9
• 34 year old nurse who presents to A/E with
dilated and fixed left pupil. This happens
shortly after a very minor assault by a patient.
• No opthalmoplegia, no headache. Has urgent
cerebral angiogram and MRI brain-both
normal.
• Visual acuity inconsistent on examination,
cocaine eye test done suggesting a local
blockade
Malingering
Pharmacological blockade
of the eye.
She left the hospital when
it was suggested, never
seen again.
Common themes of these patients
• They have evidence of something other than
straightforward psychiatric disease.
• Nearly always present on history and exam
and then confirmed via investigations.
• Take home message: be sparing in the use of
organic as a differential diagnosis and
remember that organic as a label means very
little, until it is broken down further.
How to investigate?
CT brain
• Fast
• Cheap
• Good for bone
• Good for blood and mass
lesions
• Does not visualise
brainstem, posterior fossa
or hippocampi
MRI brain
• Slower
• More expensive
• Much better resolution
• Needs cautious
interpretation
• Preferred option as a scan.
Imaging
Ct with SDH
MRI with SDH
Get the most out of your
neuroradiologist
• When writing a request, as much detail as
possible, particularly anatomical detail and
clinical detail.
• Occasionally a detailed letter and ideally face
to face contact always produces a better
service.
Get the most out of your local
neurologist
• If a neurological disorder is suspected, then
clearly get a neurology opinion which may
ultimately prove a lot cheaper and is going to
be a lot better for the patient.
Conclusion
• Be very precise when talking about organic
aetiologies
• Do the basic tests
• Be quick to refer
• Odd presentations of madness are to be
expected.
• Weird presentations of physical illness are
always far less likely but must be considered,
sought out and treated.