Stroke mimics: incidence, aetiology, clinical features and treatment

Figures & data

Table 1. Conditions that may be confused as acute stroke (stroke mimics).

Conditions	Types	Examples
	Recrudescence
	Brain disorders without structural lesions	Migraine	Peripheral vertigo
		Focal neuropathies	Transient global amnesia
		Bell’s palsy
	Brain disorders with structural lesions	Posterior reversible Vasoconstrictive syndrome (PRES)	Multiple sclerosis and other demyelinating diseases
		Seizure disorder/TPMA^a (Figure 4)	Arterio-venous malformation
		Eye disorders	Meningeal disease
		Sub-acute/acute bacterial endocarditis	Atrial myxoma
		Channelopathies	Trauma
		Epidural/subdural haemorrhage (Figure 3)	Aortic dissection
Medical mimics		Hypertensive crisis	Arnold-Chiari malformation
		Brain neoplasm	Stroke-like migraine attacks after radiation therapy (SMART) syndrome
	Systemic medical conditions	Electrolytes dysfunction	Alcohol
		Metabolic/toxic disorders	Acute liver failure
		Hypoglycaemia and hyperglycaemia
	Negative investigations (stroke misdiagnosis)
Functional mimics		Depression	Somatization
		Stress	Psychiatric complications of neurological conditions
		Anxiety disorder
		Chronic pain/fatigue

^aTPMA: transient peri-ictal MRI abnormalities.

Table 2. Clinical characteristics differentiating stroke from mimic.

Characteristic	Stroke	Mimics
Age and sex	Older age (male = female)	Younger age (females > males)
Level of consciousness	Awake	Altered level of consciousness
Onset and progress	Acute and sudden	Gradual in onset
Symptoms severity	Severe at onset	Fluctuations in severity are common
Risk factors	Vascular risk factors	Migraine, seizure, systemic illness
Vascular territory	Vascular syndromes	No vascular distribution
Blood pressures at presentation	Increase blood pressure at onset is common	Blood pressure usually not increased
Signs and symptoms	Weakness (pyramidal distribution), aphasia and visual filed defects	Sensory, vertigo (dizziness) and visual
Involuntary movements	Uncommon	May have involuntary movements
Imaging	Imaging shows ischaemic lesions	Imaging helpful in diagnosis
EEG	EEG may show slowing over the affected area	May show spike and wave in seizures Unilateral facial twitching and lip-smacking Giveaway weakness Arm drift/abrupt fall without pronation

Figure 1. Suggested approach to evaluation of acute stroke patient where mimic is suspected.

Figure 2. Patient presented with sudden onset right-sided numbness and no other deficits. Routine computed tomography (CT) was normal. A: Diffusion-weighted (1.5 T) magnetic resonance imaging (DWI-MRI) was normal. B,C: High resolution 3 T MRI (DTI and DWI-isotropic voxels) revealed left thalamus infarction.

Figure 3. 80-year-old female with atrial fibrillation on apixaban. She presented with a 90-min history of sudden onset right arm and leg weakness sparing the face with normal sensation. A,B: Axial computed tomography (CT) head, CT angiogram (not included) and CT perfusion were unremarkable. Tissue plasminogen activator (tPA) was no given because the patient is on an anticoagulant. C: Diffusion-weighted magnetic resonance imaging (DWI-MRI) was normal. D,E: Sagittal and axial MRI spine revealed right posterolateral epidural haematoma, a multifocal severe spinal canal stenosis, and spinal cord oedema.

Figure 4. An 85-year-old female presented with expressive aphasia. A,B: Axial computed tomography (CT) head, CT angiogram (not included), magnetic resonance imaging (MRI) of the brain that also included diffusion-weighted imaging were unremarkable. The patient was discharged with the diagnosis of transient ischaemic attack (TIA). After discharge, the patient continued to have recurrent similar episodes. C: CT perfusion during one of her episodes demonstrated left frontal focal hyperperfusion characterized by increased cerebral blood flow (CBF), cerebral blood volume (CBV) and decreased time to drain (TTD). The patient was diagnosed with focal seizure with preserved awareness.