Slide 1
Go through the slides to find out more about stroke mimics.
Slide 2
Intracranial structural lesion e.g. subdural haematoma, brain tumour:
These can produce the same neurological deficits as a stroke but usually they will have come on more gradually. The patient may not be able to say which day they started and often they will have noticed worsening of the symptoms since onset. However, they may present suddenly if the structural lesion has caused a epileptic seizure (which may not always have been observed or recognised) or has been complicated by a bleed. Patients who have unilateral neglect may have their problem brought to light by a fall (which is sudden) but may not report the gradual onset of problems due to a structural lesion. An early brain scan will diagnose most important structural lesions which may mimic a stroke.
Slide 3
Metabolic disorders e.g. hypoglycaemia:
Low blood sugar: A low blood sugar (hypoglycaemia) may produce symptoms which are identical to those of stroke. The clue is usually that the patient is a diabetic on insulin or a tablet such as gliclazide or glipizide (or one of the older drugs – chlorpropramide, tolbutamide and glibenclamide). Metformin does not usually cause hypoglycaemia. Also hypoglycaemia often occurs at night, so the patient wakes with the symptoms, or before meals or after strenuous exercise. However, there are some rare medical conditions when non diabetics can become hypoglycaemic so it must always be born on mind. If hypoglycaemia is a possibility then an immediate finger prick test of the blood sugar should be done.
Slide 4
Metabolic disorders e.g. hypoglycaemia (continued):
Other metabolic problems: Alcoholics and other sick patients may develop acute neurological problems related to Thiamine deficiency. They may get acute onset of confusion (loss of memory – Korsokoff’s psychosis), incoordination of gait and limbs (ataxia) and eye movement problems (double vision) which might mimic a brainstem stroke.
High blood sugars, high and low sodium, calcium and magnesium levels can cause confusion, epileptic seizures, coma and can mimic strokes. Blood tests normally provide the clue.
Slide 5
Adverse effects of drugs or alcohol:
Many drugs can affect brain function. Acute alcohol intoxication and phenytoin toxicity can cause acute incoordination which will mimic a brainstem stroke. Lithium toxicity can produce confusion, incoordination and coma. Overdoses of sedatives, opiates and antidepressants can lower conscious level and mimic severe stroke. It is important to review the patient’s prescribed and over the counter medications. Also, find out where they were found – were they actually in bed with empty pill containers by their side?? Clinical signs such as pin point pupils (due to opiates – but also occurs in bleeds into the brainstem), depressed tendon reflexes throughout may give clues. Toxicology screening would confirm the diagnosis.
Slide 6
Psychological disorders:
Patient may develop the symptoms of a stroke in response to some psychological distress. This has been called many things including hysteria, medically unexplained symptoms, functional etc etc. The clue is often in the history which may include psychological problems in the past and frequent presentations with other unexplained symptoms – e.g. irritable bowel syndrome, unexplained chest pains or breathlessness, chronic pain. The patient may not have any obvious risk factors for stroke.
Slide 7
Psychological disorders (continued):
There is often a mismatch between the apparent severity of symptoms during the examination, when a limb may be completely paralysed or numb, and the patients function which may be surprisingly good, especially when they think they are not being watched. The pattern of neurological deficit often does not fit with our understanding of anatomy and physiology. During testing of power patients often grimace a lot as if putting in lots of effort. Their weakness may fluctuate from moment to moment (so called give way weakness). Their gait may be bizarre and completely unlike that of a patient with a stroke.
The diagnosis is usually made on the basis of the atypical history and examination although normal investigations may help confirm the diagnosis. However, many patients with definite strokes have normal brain scans!
Slide 8
Epileptic seizures:
Any story of a seizure makes this a possible alternative diagnosis. If the patient has a past history of epilepsy or is on anticonvulsant drugs it must be considered. After a seizure a patient may have loss of power, feeling, speech or vision which may persist for hours or occasionally even days.
If a patient is witnessed to have a seizure at onset then the apparent stroke may be due to that seizure although some strokes will present with a seizure. Ongoing rhythmic jerking of a limb or twitching of the face might indicate ongoing seizure activity which might explain the patients apparent stroke. An electroencephalogram (EEG) may confirm the diagnosis if any seizure activity is ongoing. A bitten tongue might be a clue to an unwitnessed seizure.
Seizures may result from metabolic problems, structural lesions, drugs and toxins as well as strokes.
Slide 9
Migraine:
Migraine is a common stroke mimic in younger people but may occur at any age. The patient will often have a past history or family history of migraine although the nature of their previous attacks may be different from that which they are now presenting with.
The neurological symptoms of migraine may occur prior to, with or after any headache. Some people have migraine without any headache. Some have associated nausea and vomiting. However, many stroke patients have headache and vomiting.
Neurological symptoms in migraine are often “positive” rather than negative. – “positive visual symptoms” often described as flashing lights, zig zags, kaleidoscope vision, wavy lines. They occur in both eyes although sometimes are more marked in one than the other – they may be a subtle as a bit of blurring, lots of moving dots or sensitivity to light.
Slide 10
Migraine (continued):
“Positive sensory symptoms” include pins and needles but may be associated with numbness of face, arm and/or leg. Migraine may cause word finding difficulties or jumbled speech. It may cause heaviness or even weakness of arms and legs although complete paralysis is very unusual.
In stroke the neurological deficits usually all come on together. In migraine the symptoms vary over minutes or hours. Often visual symptoms come first but may then be replaced by speech problems, sensory symptoms or heaviness.
Investigations are often reassuringly normal, though sometimes after a severe migraine an area of brain infarction can be detected. There is definitely an overlap between stroke and migraine.
Slide 11
Previous stroke with residual deficits made worse by intercurrent illness e.g. infection:
It can be very difficult to distinguish a new stroke from an old one. If a patient has had a history of a previous stroke find out if the neurological deficit had persisted and what they were. Recurrence of the same deficits makes an intercurrent illness a distinct possibility. Asking patients about symptoms of epileptic seizure or infection and doing some simple laboratory tests (white cell count, C reactive protein, urine dipstick and mid stream urine culture) chest X ray will often provide a clue. A diffusion weighted image on MRI can often distinguish a new area of brain infarction from an old area due to a previous stroke.
