Sunday, 15 June 2014

Dizziness Part II: Evaluation & finding the cause of Dizziness

Dizziness evaluation is a time consuming task.Sometimes the assessment process may take few visits.
The cause of dizziness could range from peripheral vestibular disorders (related to the ear & it's structures) to Central disorders(related to other pathways connecting the balance systems including brain).
The doctors also has to rule out other causes like low blood pressure,some heart conditions to thyroid dysfunction.

The most important step towards reaching a diagnosis is history i.e.patients story.I usually encourage the patients to describe their symptoms in words other than "dizzy".

Narrate your story & if possible write it before visiting your doctor.
Important information to write down will be :
-What is the feeling during the attack ?is it rotation or unsteadiness or black out,associated with nausea or vomiting 
-How long does it lasts?seconds,minutes or hours & days.Frequency in a week,month or year.
-What are the triggers?does change of position have an effect?Is it related to viral fever,cold,noise,social situations etc
-Are there associated symptoms like ringing sound in the ear,ear fullness or deafness
-other symptoms like double vision or weakness of limbs or gait problems
-Medical history of self & family
-Treatment you have received so far & carry your medical records

I also ask patients some direct questions to complete the history.

Dr Micheal Strupp,one of the pioneers in vertigo & dizziness says 90% of the diagnosis is clinical especially good history taking.All common causes like BPPV,Meneire's disease,Vestibular neuronitis & Vestibular migraine are diagnosed by good history alone.I had to opportunity not just to meet him but also attend his masterclass on this topic.

Clinical examination:
I as a doctor need to come to two main conclusions

1.Is there a deficit?
2.Is it peripheral or central?

Bedside examination includes examination of vestibular & oculomotor system 
I am just naming them as complete description is beyond the preview of this blog meant for patients education.However just to prepare you for the doctors visit ,I must say this will involve the doctor asking you to follow the instructions to move eyes in different directions(nystagmus & saccades).It will also involve shaking your head in either direction (head tilt).The doctor will also hold your head & bring you down on the couch from sitting to lying down on each side.Finally gait or your walk will be tested with eyes open & closed.

These clinical tests are namely
1.Ocular tilt
2. Nystagmus -peripheral versus central
3. Vestibulo Ocular Reflex / head impulse test
4. Central oculomotor,vestibular or cervical reflex
5. Gait

As already mentioned 90% of diagnosis of common presentations of dizziness is clinical.Rare presentations like Multiple Sclerosis,Brain stem encephalitis or infarction will need radiology imaging like MRI.Some conditions like Meneire's an audiogram is advised.


Some Causes of Dizziness and Vertigo

1.Benign paroxysmal positional vertigo
Severe, brief (< 1 min) spinning triggered by moving head in a specific direction

2.Meniere disease
Recurrent episodes of unilateral tinnitus, hearing loss, ear fullness

3.Vestibular neuronitis (viral cause suspected)
Sudden, incapacitating, severe vertigo with no hearing loss or other findings
Lasts up to 1 wk, with gradual lessening of symptoms

4.Trauma (eg, tympanic membrane rupture, labyrinthine contusion, perilymphatic fistula, temporal bone fracture, post concussion)

5. Ototoxic drugs
Treatment with aminoglycoside drugs recently instituted, usually with bilateral hearing loss and vestibular loss

6. Chronic motion sickness 
Persistent symptoms after acute motion sickness

7.Central vestibular system disorders
-Acoustic neuroma
Slowly progressive unilateral hearing loss, tinnitus, dizziness, dysequilibrium
-Brain stem hemorrhage or infarction
Sudden onset
-Cerebellar hemorrhage or infarction
Sudden onset, with ataxia and other cerebellar findings, often headache

8. Migraine
Episodic, recurrent vertigo, usually without unilateral auditory symptoms (may have tinnitus that is usually bilateral)
Possibly headache, but often personal or family history of migraine
Photophobia, phonophobia, visual or other auras possible, helping make diagnosis

9. Multiple sclerosis
Varied CNS motor and sensory deficits, with remissions and recurring exacerbations

10. CNS-active drugs' (not ototoxic)
Drug recently instituted or dose increased; multiple drugs, particularly in an elderly patient

11. Hypoglycemia (usually caused by drugs for diabetes)

12. Hypotension (caused by cardiac disorders, antihypertensives, blood loss, dehydration, or orthostatic hypotension syndromes including postural orthostatic tachycardia syndrome and other dysautonomias)

13. Other causese
Psychiatric 
Syphilis
Thyroid disorders

List is in rough order of frequency of occurrence.

Note: drugs, including aminoglycosides, chloroquine ,Lasix  including most antianxiety, anticonvulsant, antidepressant, antipsychotic, and sedative drugs. Drugs used to treat vertigo are also included.




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