Orthostatic hypotension and postural tachycardia (POTS)

In the practice

• Blood pressure and heart rate after 5 minutes lying then 3 minutes standing; ECG; medication review.

Laboratory tests

• FBC
• Serum electrolytes
• Serum creatinine with eGFR
• Fasting plasma glucose
• TSH
• Vitamin B12
• Serum protein electrophoresis (if associated peripheral neuropathy, to look for a monoclonal gammopathy)if needednon-French guidelineOrthostatic hypotension with signs of peripheral neuropathy: the 2017 American consensus places this test second-line, in these patients, to look for a monoclonal gammopathy ^[2]. The French consensus lists amyloidosis among the causes, without a list of tests ^[3].

In the practice

• Heart rate and blood pressure lying then standing (standing for more than 30 seconds); 12-lead ECG.

Laboratory tests

• FBC
• TSH

Laboratory tests

• Serum creatinine with eGFR (midodrine: before treatment, then regularly long term)if neededPatient on midodrine (Gutron): contraindicated in severe renal failure; long-term monitoring of kidney function advised (SmPC) ^[10].
• ASTif needednon-French guidelinePatient on midodrine: the UK SmPC recommends assessing kidney and liver parameters before treatment and then regularly, as there are no studies in hepatic impairment ^[11]; the Dutch formulary asks for liver and kidney checks before treatment ^[12]. The French SmPC cites long-term kidney monitoring, not liver monitoring ^[10].
• ALTif needednon-French guidelinePatient on midodrine: the UK SmPC recommends assessing kidney and liver parameters before treatment and then regularly, as there are no studies in hepatic impairment ^[11]; the Dutch formulary asks for liver and kidney checks before treatment ^[12]. The French SmPC cites long-term kidney monitoring, not liver monitoring ^[10].
• Serum electrolytes (fludrocortisone: potassium and sodium)if neededPatient on fludrocortisone (off-label for this indication): monitor serum potassium and sodium, with blood pressure and weight ^[3].