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A transient ischaemic attack (TIA) is defined as neurological deficits that completely resolve within 24 hours . 80% of TIAs are due to thromboemboli, which occur almost exclusively in patients with symptomatic large vessel disease, e.g., carotid artery stenosis.
A transient event is more likely to be vascular if the patient has a high ABCD2 score . Patients with a score of ≥ 4 are admitted to hospital for investigation within 24 hours
Features of a Transient Ischemic Attack (ABCD2 score)
Component Points Age ≥ 60 years 1 Blood pressure ≥ 140/90 mmHg 1 Clinical features: a) unilateral weakness, b) speech disturbance with no weakness a) 2, b) 1 Duration of symptoms a) 10 – 60 minutes, b) > 60 minutes a)1, b) 2 History of Diabetes 1
This gives a total score ranging from 0 – 7. Patients with a suspected TIA and are at a higher risk of stroke have an ABCD2 score of ≥ 4 .
A crescendo TIA (2 or more episodes in a week) is treated as being a high-risk of stroke even with an ABCD2 score of < 4.
Causes
Atherothromboembolism
Cardioembolism (from mural thrombus)
Hyperviscosity
Polycythaemia
Sickle-cell anaemia
Myeloma
Vasculitis
Cranial arteritis
Polyarteritis nodosa
SLE Syphilis
Physical examination
Carotid bruit
High blood pressure
Radial/radial delay and difference in brachial pressure > 200 mmHg suggest subclavian artery stenosis
Differentials
Hypoglycaemia Focal epilepsy with Todd’s paralysis
Migraine
Malignant hypertension
Multiple sclerosis 9paroxysmal dysarthria)
Intracranial tumors
Peripheral neuropathy
Phaechromocytoma
Somatization
Investigations
Electrocardiogram Echocardiogram
Carotid doppler +/- angiography
Blood glucose
Complete blood count
UECs
Lipid panel
Non-contrast CT scan or DWI MRI
Treatment
Optimize cardiovascular risk factors
Aspirin or clopidogrel 300 mg STAT
Anticoagulation if indicatedCarotid edarterectomy if indicated
Suffered stroke or TIA in the carotid territory and is not severely disabled
Carotid stenosis > 70% (ECST criteria) or 50% (NSCET criteria)
Prohibit driving for at least 1 month
Biochemistry
ACTH P: <80 ng/L ALT P: 5–35 U/L Albumin P: 35–50 g/L Aldosterone P: 100–500 pmol/L Alk. phosphatase P: 30–130 U/L α-Amylase P: 0–180 IU/dL α-Fetoprotein S: <10 kU/L Angiotensin II P: 5–35 pmol/L ADH P: 0.9–4.6 pmol/L AST P: 5–35 U/L Bicarbonate P: 24–30 mmol/L Bilirubin P: 3–17 μmol/L BNP P: <50 ng/L CRP P: <10 mg/L Calcitonin P: <0.1 mcg/L Calcium (ionized) P: 1.0–1.25 mmol/L Calcium (total) P: 2.12–2.60 mmol/L Chloride P: 95–105 mmol/L Cholesterol P: <5.0 mmol/L VLDL P: 0.128–0.645 mmol/L LDL P: <2.0 mmol/L HDL P: 0.9–1.93 mmol/L Cortisol AM P: 450–700 nmol/L Cortisol Midnight P: 80–280 nmol/L CK ♂ P: 25–195 U/L CK ♀ P: 25–170 U/L Creatinine P: 70–100 μmol/L Ferritin P: 12–200 mcg/L Folate S: 2.1 mcg/L FSH P: 2–8 U/L ♂; >25 menopause GGT ♂ P: 11–51 U/L GGT ♀ P: 7–33 U/L Glucose (fasting) P: 3.5–5.5 mmol/L Growth hormone P: <20 mu/L HbA1C (DCCT) B: 4–6% HbA1C (IFCC) B: 20–42 mmol/mol Iron ♂ S: 14–31 μmol/L Iron ♀ S: 11–30 μmol/L Lactate (venous) P: 0.6–2.4 mmol/L Lactate (arterial) P: 0.6–1.8 mmol/L LDH P: 70–250 U/L LH P: 3–16 U/L Magnesium P: 0.75–1.05 mmol/L Osmolality P: 278–305 mosmol/kg PTH P: 0.8–8.5 pmol/L Potassium P: 3.5–5.3 mmol/L Prolactin ♂ P: <450 U/L Prolactin ♀ P: <600 U/L PSA P: 0–4 mcg/mL Protein (total) P: 60–80 g/L Red cell folate B: 0.36–1.44 μmol/L Renin (erect) P: 2.8–4.5 pmol/mL/h Renin (recumbent) P: 1.1–2.7 pmol/mL/h Sodium P: 135–145 mmol/L TBG P: 7–17 mg/L TSH P: 0.5–4.2 mU/L T4 P: 70–140 nmol/L Free T4 P: 9–22 pmol/L TIBC S: 54–75 μmol/L Triglycerides P: 0.50–2.3 mmol/L T3 P: 1.2–3.0 nmol/L Troponin T P: <0.1 mcg/L Urate ♂ P: 210–480 μmol/L Urate ♀ P: 150–390 μmol/L Urea P: 2.5–6.7 mmol/L Vitamin B12 S: 0.13–0.68 nmol/L Vitamin D S: 50 nmol/L
Arterial Blood Gases
pH 7.35–7.45 PaCO₂ 4.7–6.0 kPa PaO₂ >10.6 kPa Base excess ±2 mmol/L
Urine
Cortisol (free) <280 nmol/24h Hydroxyindole acetic acid 16–73 μmol/24h Hydroxymethylmandelic acid 16–48 μmol/24h Metanephrines 0.03–0.69 μmol/mmol cr. Osmolality 350–1000 mosmol/kg 17-Oxogenic steroids ♂ 28–30 μmol/24h 17-Oxogenic steroids ♀ 21–66 μmol/24h 17-Oxosteroids ♂ 17–76 μmol/24h 17-Oxosteroids ♀ 14–59 μmol/24h Phosphate (inorganic) 15–50 mmol/24h Potassium 14–120 mmol/24h Protein <150 mg/24h Protein/creatinine ratio <3 mg/mmol Sodium 100–250 mmol/24h
Haematology
WCC 4.0–11.0 ×10⁹/L RBC ♂ 4.5–6.5 ×10¹²/L RBC ♀ 3.9–5.6 ×10¹²/L Hb ♂ 130–180 g/L Hb ♀ 115–160 g/L PCV ♂ 0.4–0.54 L/L PCV ♀ 0.37–0.47 L/L MCV 76–96 fL MCH 27–32 pg MCHC 300–360 g/L RDW 11.6–14.6% Neutrophils 2.0–7.5 ×10⁹/L (40–75%) Lymphocytes 1.0–4.5 ×10⁹/L (20–45%) Eosinophils 0.04–0.44 ×10⁹/L (1–6%) Basophils 0–0.10 ×10⁹/L (0–1%) Monocytes 0.2–0.8 ×10⁹/L (2–10%) Platelets 150–400 ×10⁹/L Reticulocytes 0.8–2.0% / 25–100 ×10⁹/L Prothrombin time 10–14 s APTT 35–45 s
Paediatric
Pulse Rate (bpm) Neonate 140–160 Infant <1yr 120–140 1–5 years 110–130 5–12 years 80–120 >12 years 70–100 Respiratory Rate (tachypnoea) 0–2 months ≥60/min 2–12 months ≥50/min 1–5 years ≥40/min >5 years ≥30/min Blood Pressure (mmHg) Term 65/45 1 year 75/50 4 years 85/60 8 years 95/65 10 years 100/70 Weight Formulas 3–12 months (a + 9)/2 kg 1–6 years 2a + 8 kg >6 years (7a − 5)/2 kg Haemoglobin (g/dL) Term newborn 13–20 1 month 11–18 2 months 10–15 1–2 years 10–13 >2 years 11–14 MUAC (6 months–5 years) Obese >17.5 cm Normal 13.5–17.4 cm At risk 12.5–13.4 cm Moderate malnutrition 11.5–12.4 cm Severe malnutrition <11.5 cm Developmental Milestones Social smile 1.5 months Head control 4 months Sits unsupported 7 months Crawls 10 months Stands unsupported 10–12 months Walks 12–13 months Talks 18 months CSF WBC (/mm³) Term newborn 0–25 >2 weeks 0–5