Hypotension

CLINICAL DIAGNOSTIC MANUAL

Hypotension is defined as abnormally low blood pressure, typically below 90/60 mmHg. This condition can be benign in some cases, such as in young and healthy individuals, but it can also be a sign of underlying pathologies when it presents acutely or chronically, especially if accompanied by symptoms.

Hypotension can result from a reduction in blood volume, an alteration in the heart’s ability to pump blood properly, or excessive dilation of the blood vessels. Its manifestations vary depending on the cause and the speed at which the drop in blood pressure occurs.

Pathology	Symptoms and Clinical Signs	Suspected Diagnosis	Confirmed Diagnosis
Heart failure	Fatigue, dyspnoea, peripheral oedema, orthopnoea, weak pulse, persistent hypotension.	Clinical suspicion based on signs of low cardiac output and history of heart disease.	Echocardiogram showing systolic or diastolic dysfunction, elevated BNP (B-type natriuretic peptide).
Arrhythmias	Palpitations, dizziness, syncope, irregular pulse, intermittent hypotension.	History of episodes of palpitations and syncope associated with hypotension.	Electrocardiogram (ECG) showing arrhythmias (atrial fibrillation, ventricular tachycardia, etc.).
Myocardial infarction	Chest pain, dyspnoea, sweating, dizziness, syncope, hypotension, nausea.	History of chest pain with cardiovascular risk factors.	ECG with ischaemic changes, elevated cardiac markers (troponin).
Hypovolaemia (haemorrhage, dehydration)	Tachycardia, cold and pale skin, thirst, confusion, reduced urine output, hypotension.	Suspected based on signs of dehydration or active/recent haemorrhage.	Full blood count (anaemia in haemorrhage), plasma volume measurement, ultrasound to detect haemorrhages.
Septic shock	Fever, confusion, tachycardia, rapid breathing, severe hypotension, cold or warm skin.	Suspected in the presence of severe infection signs with hypotension refractory to fluids.	Positive cultures, elevated lactate levels, persistent hypotension despite IV fluids.
Anaphylactic shock	Urticaria, angioedema, dyspnoea, wheezing, dizziness, syncope, sudden hypotension.	History of allergen exposure with acute cutaneous and respiratory symptoms.	Specific IgE tests, rapid response to epinephrine and intravenous fluids.
Orthostatic hypotension	Dizziness when standing, syncope, blurred vision, fatigue, hypotension while standing.	Drop in blood pressure when changing position from seated to standing.	Tilt table test showing a drop in blood pressure upon standing.
Adrenal insufficiency (Addison’s disease)	Fatigue, weight loss, hyperpigmentation, persistent hypotension, nausea, vomiting.	Persistent hypotension, hyperpigmentation, and general weakness.	ACTH stimulation test (low cortisol levels), hyponatraemia and hyperkalaemia in blood tests.
Hypothyroidism	Fatigue, weight gain, dry skin, bradycardia, cold intolerance, hypotension.	Classic signs of hypothyroidism such as fatigue and bradycardia.	Elevated TSH with low free T4 levels in blood tests.
Hypoglycaemia	Sweating, palpitations, hunger, confusion, dizziness, hypotension, seizures (in severe cases).	History of hunger, sweating, and confusion episodes after fasting or exercise.	Low plasma glucose during the episode, symptom resolution with glucose administration.
Malnutrition	Weight loss, weakness, hypotension, fatigue, dizziness.	History of significant weight loss and insufficient caloric intake.	Low albumin levels, blood tests showing nutrient deficiencies.
Medication overdose	Dizziness, bradycardia, severe hypotension, confusion, slow breathing (in beta-blocker or ACE inhibitor overdose).	History of recent use of medications affecting blood pressure.	Serum concentration of the drugs, ECG (bradycardia or conduction disturbances).
Autonomic nervous system disorders (dysautonomia)	Dizziness, heat intolerance, altered sweating, blurred vision, postural hypotension.	History of symptoms related to the autonomic nervous system.	Tilt table test, autonomic function tests (such as heart rate variability).
Neurogenic shock	Severe hypotension, bradycardia, warm and dry skin, absence of sympathetic reflexes.	History of recent trauma or spinal cord injury with hypotension and bradycardia.	MRI to assess spinal cord injury, low blood pressure without sympathetic compensatory response.
Sepsis	Fever or hypothermia, tachycardia, rapid breathing, hypotension, confusion, oliguria.	Suspected in the presence of infection signs and multi-organ failure with hypotension.	Positive blood cultures, elevated procalcitonin or lactate levels, septic shock criteria.