Syncope and Type 1 RTA

Today we presented an interesting case of syncope, due to AVRT in the setting of hypokalemia thought to be due to an incomplete type 1 RTA. 

1. When thinking about syncope consider the 5 categories of causes of an syncope:

-Neurally Medicated Syncope (Reflex Syncope): Vasovagal, Situational, Carotid Sinus Syndrome

-Orthostatic Syncope: Primary (primary autonomic failure), Secondary (DM, amyloidosis, spinal cord injuries, parkinsons, hypovolemia), Drug Induced, Volume Depletion

-Cardiac Syncope: Tachy or Brady Arrhythmia, Atrioventricular Block, Structural heart disease (Cardiomyopathy, Hypertrophic cardiomyopathy, Atrial Myxoma, Ischemia), PE, Aortic dissection, Pulm

-Cerebrovascular Syncope: Verterobasilar TIA, Subclavian Steal


2. When deciding to admit a patient to the hospital for syncope you can use the ROSE rules (Risk stratification Of Syncope in the Emergency department), if any are positive then the patient should be considered high risk and admitted for further evaluation.

  • elevated B-type natriuretic peptide concentration (≥300 pg/mL)

  • bradycardia (≤50 beats/minute)

  • fecal occult blood in patients with suspected gastrointestinal bleeding

  • anemia (hemoglobin ≤9 g/dL [90 g/L])

  • chest pain with syncope

  • ECG with Q waves (not in lead III)

  • oxygen saturation less than or equal to 94% on ambient air.

3. When a patient has an acidosis then their urine pH should be less than 5.3, if it is not then consider a type 1 RTA, this could either be a partial or complete type 1 RTA.  A pH of over 5.3 shows that they are unable to properly acidify their urine.  Other features of a type 1 RTA include hypokalemia, + urine anion gap, increased urine calcium/creatinine ratio and nephrolithiasis.