Dizzy spells - a common complaint with many possible causes
From DoctorMyhill
This is such a common symptom and feedback from the website shows that this page is the most often visited and so hence this update!
There are two approaches to analysing the cause of dizzy spells. The first is the entirely logical one and the second is the "common things are common" approach. So, let us go through the logical reasons why one may suffer from dizzy spells first.
Logical reasons for dizzy spells
By dizzy spells people can actually mean several different things. If by dizzy spells they mean that the world is spinning round, associated with nausea and hearing loss and noises in the ear, then this is suggestive of labyrinthitis, which may be caused by inflammation in the inner ear, or poor blood supply to the inner ear. However, the vast majority of dizzy spells are not due to inner ear pathology. These cases of dizziness result either from poor fuel supply to the brain, or poor oxygen supply to the brain, or both combined.
Causes of poor FUEL supply to the brain (oxygen supply OK)
Causes of low OXYGEN in the blood (fuel supply OK)
- Respiratory failure – obviously if the lungs do not work properly then oxygen tensions will be low. This only occurs in severe advanced respiratory disease (chronic obstructive airways disease, pulmonary embolus, collapsed lung, lungs full of fluid, cancer etc) and is accompanied by severe shortness of breath.
- Hyperventilation – in hyperventilation, the rate of respiration is too fast. When this occurs carbon dioxide is washed out of the blood, which changes the acidity in such a way that oxygen sticks more avidly to haemoglobin. So oxygen levels in the blood as measured are fine, but this oxygen cannot be released at the tissue levels, where it is needed. See Hyperventilation for further details.
- Carbon monoxide poisoning – here the mechanism for low oxygen is the same as for hyperventilation. Interestingly carbon monoxide is also produced when the metabolism is stressed, i.e. one does not have to be exposed to carbon monoxide from the outside world to suffer CO poisoning. See Carbon monoxide poisoning and multi-sensitivity.
- Patent foramen ovale This, according to Cheney, is present in 90% of patients with CFS. It explains sudden worsening of symptoms, including feeling dizzy and acute fatigue, following a fairly minor stress. See Patent foramen ovale as a cause of fatigue
Causes of poor fuel and oxygen supply - i.e. poor blood supply
- Anaemia – i.e. not enough blood to circulate. See Anaemia
- Low blood pressure – can be caused by low cardiac output state or heart failure See Low cardiac output state.
- Autonomic dysfunction – i.e. the nerves which control blood pressure are malfunctioning. See Autonomic neuropathy
- Vasovagal reaction – this reflex occurs with, for example, intense fear, or bowel movement, or waking in the night and having a pee (micturition syncope) may cause a drop in blood pressure.
- Low blood pressure in the brain can be due to the arteries being clogged up with atherosclerosis. If little flecks of atherosclerosis break off then this will completely interrupt the blood supply to the part of the brain and can cause transient ischaemic attacks or strokes. See Arteriosclerosis - what causes it and how to prevent it
- Hormonal effects – both hypothyroidism and hypoadrenalism can result in low blood pressure. See Hypothyroidism - diagnosis of and Adrenal Gland - the gear box of the car (DHEA and cortisol) – underactive.
- Generalised vasodilatation – i.e. all the blood vessels to the skin open up. This can drop the blood pressure and one example of this would be simply being too hot.
- Lack of sleep.
- Prescription medication.
- Dehydration - if you wait until you feel thirsty before drinking then you are already dehydrated!
- Salt and minerals - water "follows" salt and minerals - you cannot rehydrate until you have adequate levels of minerals Nutritional Supplements - what everybody should be taking all the time even if nothing is wrong.
"Common things are common" - common causes of dizziness
My experience is that the commonest causes of dizzy spells in order of likelihood are:
- Hypoglycaemia.
- Dehydration and mineral deficiency
- Prescription medication and other such poisonings!
- Low blood pressure due to low cardiac output
- Lack of sleep
- Hyperventilation - usually occurs with panic attacks. Most people who hyperventilate don't think they are!
- Poor thyroid and/or adrenal function
Related Tests
Related Articles
- Hyperventilation
- Hypoglycaemia
- Hypothyroidism - diagnosis of
- Low blood pressure and postural hypotension
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