Diagnosing LPR
LPR or 'Silent Reflux' can be difficult to diagnose, certainly more so than typical reflux.
A large proportion of the people we treat present with LPR symptoms, these are often experienced in the upper airways. As such we are familiar with it and have developed a range of tests to confirm a diagnosis of LPR, and to inform future treatment.
As you'll see repeated elsewhere on this site, having the right tests and having them correctly executed and interpreted is critical to your successful treatment.
The LPR Tests we Use
Tests in patients with LPR are aimed at two outcomes. Firstly, to exclude a malignant cause for symptoms and secondly to establish if reflux is their cause and if so what is the underlying problem. Sometimes the diagnosis can be made easily, for instance following an endoscopy. In some patients it can be necessary to perform several tests, tailored to their symptoms, to build up a picture so that an individualised treatment plan can be agreed. The interpretation of the results can also be very influential in understanding the problem and this is another reason why the Multi-Disciplinary Team (MDT) approach can be so important in getting the best outcome.
- Imaging; Sometimes a CT or MRI of the neck and sinuses is requested to exclude malignancy or look for evidence of sinus inflammation. A Barium swallow x-ray can identify a pharyngeal pouch and a chest x-ray lung disease.
Endoscopy; During naso-endoscopy a tiny camera is inserted through the nose to look at the throat and larynx. This can identify multiple abnormalities including evidence of reflux damage. If reflux is identified an upper gi endoscopy (otherwise known as a gastroscopy) will look at the oesophagus, stomach and duodenum. Both can be undertaken under local anaesthetic or sedation. Occasionally in patients with LPR symptoms it may be necessary to perform a direct laryngoscopy: This employs a tube called a laryngoscope. This procedure enables direct visualisation of the throat and removal of a foreign object or to sample tissue for a biopsy. It is performed under general anaesthetic.
Oesophageal physiology tests; these measure oesophageal function and reflux. High Resolution Manometry (HMR) employs a tiny catheter that is passed through the nose into the oesophagus. This will then assess the strength and function of the upper and lower oesophageal sphincters as well as measure how well swallowing is functioning. It can identify specific motility disorders such as achalasia. Impedance reflux test; Originally reflux testing measured just acid levels at the bottom of the oesophagus over 24 hours using a small catheter tube placed through the nose. Many centres continue to employ pH monitoring, but a better test uses “impedance” which can also record non-acidic reflux and distinguish between liquid, gas and solid. Consequently, this can be particularly helpful in patients with LPR symptoms. The catheter is connected to a small recorder that patients wear on a belt and on which they can record symptoms. The data recorded can therefore assess reflux of all sorts, correlate the association of symptoms with reflux and therefore indicate a causal relationship and also identify some other functional disorders that should be distinguished from reflux such as rumination syndrome. Its important to understand that reflux can vary day to day and that the tests provides results as a snap-shot in time. Consequently, in some patients it will provide a “false-negative”, suggesting there is no reflux when there is. Bravo®; An alternative to the catheter tests, this involves placing a tiny capsule onto the lining at the bottom of the oesophagus. The advantages are firstly that data is sent wirelessly by Bluetooth to a recorder and so there is no catheter, which some people find uncomfortable, to interfere with normal behaviour. Secondly, the capsule, which passes naturally, is designed to stay in placed for at least 48 and sometimes 96 hours and so can identify reflux if its present on only some days. Apart from requiring an endoscopy to place, the other drawback is that Bravo can only measure acid so in patients with non-acidic reflux it may fail to identify the problem.
- SIBO/Intolerance Breath tests; breath tests are most commonly used to diagnose small intestinal bacterial overgrowth (SIBO) and malabsorption of sugars such as lactose or fructose. In the case of (SIBO), following drinking a sugar solution the exhaled breath is tested over two hours to measure the production of hydrogen and methane gases by gut bacteria.
- Gastric Emptying Studies; These assess how quickly a substance passes from the stomach into the small bowel either directly using radio-isotopes (usually technetium-99m) or indirectly using breath tests. It can help diagnose gastroparesis or a blockage.
- Electrogastrogram; Delayed emptying can have many causes and measuring the electrical activity in the stomach can help distinguish them from each other. This can be done using electrodes placed on the skin and is painless and non-invasive.
