Initial Evaluation of Dizziness, OI
    •  Preparing - 1st Visit
    •  Get a Diagnosis-1st Visit
    •  List of Possible Causes-OI
    • 1st Visit - Lab & Tests
Get a Diagnosis: First Visit

Initial Evaluation - List of Possible Causes of Dizziness & Syncope

These are some of the conditions known to have dizziness and orthostatic symptoms. It is known as the "differential diagnosis" list - the list of different diagnoses that could cause dizziness symptoms and fainting.

As the physician listens to the history and the symptoms, some of the possible causes will be marked off the list.

The physical exam will show whether there are physical findings that go with a particular diagnosis.

From there, the physician will decide which tests are needed.
    •  If the test is negative, that diagnosis is checked off the list.
    •  If it is positive, it helps identify the diagnosis that is causing the symptoms.



Conditions Producing Syncope & Orthostatic Symptoms1-5
       Heart Rate/Rhythm

     — Sinus Node, AV conduction, SVT, VT

     — Inherited Syndrome

     — Implanted Device

     — Drug Induced

      Structural or Heart-Lung disease

     — Constrictive pericarditis

     — Aortic Stenosis

     — Cardiomyopathy

     — Pulmonary Embolism or Pulmonary Hypertension

  Endocrinologic Disorders

     — Addison's (volume depletion)

     — Pheochromocytoma

     — Hypoaldosteronism

     — Renal artery hypertension

   Hypovolemic Disorders (Orthostatic Hypotension)

     — Anemia

     — Decreased plasma volume

               » POTS (Postural Orthostatic Tachycardia Syndrome)

               »  Prolonged bedrest - e.g. long ICU-stay, traumatic head injury

     — Chemotherapy

     — Hemorrhage

     — Anorexia nervosa

        — Vomiting

     — Diarrhea

     — Overdialysis

     — Overdiuresis

   Miscellaneous Causes

     — Drugs (antihypertensives, diuretics, antidepressants, etc)

     — Pregnancy

     — Space flight

   Autonomic Neuropathies


     — Bradbury-Eggleston syndrome

     — Shy-Drager syndrome

     — Riley-Day syndrome

     — Dopamine-β-hydroxylase deficiency

   POTS (Postural Orthostatic Tachycardia Syndrome)

     — Partial Primary Dysautonomia

     — Secondary: Hypermobility, EDS, Diabetes, Paraneoplastic


     — Diabetes mellitus

     — Uremia

     — Guillain-Barre syndrome

     — Amyloidosis

        — Familial Dysautonomia   
        — Paraneoplastic autonomic neuropathy

     — Sjögren's Syndrome

     — Porphyria

     — Idiopathic - Immune mediated

Transient Neurogenic (Autonomic) Syncope

     — Micturition syncope

     — Carotid sinus syncope

     — Vasovagal syncope

     — Bezold-Jarisch reflex activation

     — Glossopharyngeal neuralgia

Neurally-Mediated Hypotension (NMH)

   Vascular Insufficiency/Vasodilatation

     — Varicose veins

     — Arteriovenous malformations

     — Absent venous valves

     — Carcinoid

     — Mastocytosis

     — Hyperbradykininism


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  1. Medow MS, Stewart JM, Sanyal S, Mumtaz A, Stca D and Frishman WH. Pathophysiology, Diagnosis, and Treatment of Orthostatic Hypotension and Vasovagal Syncope. Cardiology in Review 2008;16(1):4-20. Abstract.
  2. Moya A, Sutton R, Ammirati F, Blanc JJ, Brignole M et al., Guidelines for the diagnosis and management of syncope (version 2009). European Heart Journal (2009); 30: 2631-2671.
  3. Brignole M. Diagnosis and Treatment of Syncope. Heart 2007: 93; 130-136. Article PDF
  4. Stewart JM, Medow MS, Alejos JC. Orthostatic Intolerance. Medscape article.
  5. Figueroa JJ, Basford JR, Low PA. Preventing and treating orthostatic hypotension: As easy as A, B, C. Cleve Clin J Med. 2010 May;77(5):298-306.  Abstract.  Article PDF.
  6. Freeman, Roy. Neurogenic orthostatic hypotension.NEJM 2008;358(6):615-624. Abstract

Author: Kay E. Jewell, MD
Page Last Updated: August 22, 2012