Table 2

Second line investigations in selected stroke patients

Investigation Indications Disorders suggested
Liver function testsFever, malaise, raised erythrocyte, ESR, malignancyGiant cell arteritis, infective and non-bacterial  thrombotic endocarditis
CalciumHypercalcaemia may rarely cause recurrent focal  symptomsHypercalcaemia
Activated partial thromboplastin time, dilute Russell's viper venom time, anticardiolipin antibody, antinuclear and other antibodiesYoung patient, previous or family history of venous  thrombosis, recurrent miscarriages,  thrombocytopenia, cardiac valve vegetations, livedo  reticularis, raised ESR, malaise, positive VDRLAntiphospholipid antibody syndrome, systemic  vasculitis, systemic lupus erythematosus
Protein C and S, antithrombin III, activated protein C resistance, thrombin timePrevious or family history of thrombosis (usually  venous) of young onsetDeficiency states
Serum proteins and electrophoresis, plasma viscosityRaised ESRParaproteinaemias, nephrotic syndrome, cardiac  myxoma
Haemoglobin electrophoresisAfroCaribbean patientsSickle cell trait or disease, other  haemoglobinopathies
Blood culturesFever, cardiac murmur, haematuria, deranged LFTs,  raised ESR, malaiseInfective endocarditis
VDRL, HIV serologyYoung, unexplained or “at risk” Neurosyphilis, AIDS
Serum homocysteine, urinary amino acidsMarfanoid habitus, high myopia, dislocated lenses,  osteoporosis, mental retardation, youngHomocystinuria
Leucocyte α-galactosidase ACorneal opacities, cutaneous angiokeratomas,  paraesthesias and pain, renal failureFabry's disease
Blood/CSF lactate, mitochondrial DNA analysisYoung, basal ganglia calcification, epilepsy,  parieto-occipital ischaemia, migraineMELAS/mitochondrial cytopathy
Drug screen (blood or urine)“At risk” patient, no other causeDrug induced stroke (amphetamine, cocaine, etc)
Chest radiographyHypertension, finger clubbing, cardiac murmur or  abnormal ECG, youngCalcified valves, enlarged heart, pulmonary AVM
Carotid ultrasound/MR angiographyCarotid distribution stroke in patient suitable for  surgeryCervical internal carotid stenosis
Cerebral angiography (intra-arterial digital subtraction or MR)Young unexplained stroke, especially associated with  pain or trauma, suspected arteritis, AVM or  aneurysmArterial dissection, vascular abnormality
Transthoracic echocardiographySuspected cardioembolismCardioembolism
Transoesophageal echocardiographySuspected cardioembolism when TTE negative
 (eg endocarditis, atrial septal aneurysm), aortic  dissection or atheroma, patent foramen ovale
Cardioembolism, aortic dissection or atheroma,  paradoxical embolism
24 hour ECGPalpitations, suspicious resting ECG, clinical  suspicionIntermittent AF, heart block
Temporal artery biopsyOlder (>60), jaw claudication, headache, polymyalgia,  malaise, anaemia, raised ESRGiant cell arteritis
  • ESR=erythrocyte sedimentation rate; VDRL=venereal disease research laboratory test; AVM=arteriovenous malfunction; LFT=liver function test; TTE=transthoracic echocardiography; AF=atrial fibrillation.