To investigate among phrenic neuropathy patients: (1) occurrences of water immersion induced dyspnea, (2) clinical, electrophysiological, sonographic, and pulmonary function test abnormalities, and (3) physician documented counseling regarding risks of water related activities.

Water immersion results in upward buoyancy effect on the diaphragm and increased chest wall pressure thereby reducing lung capacity as much as 50% in patients with diaphragmatic weakness. Despite this known effect, the potential risks of submersion and water-related activities are often overlooked by patients and clinicians.

Of 535 phrenic neuropathy cases, dyspnea with water activities was documented in 4% (22/535). The majority were men (81.9%), mean age 55 years (range 31-79) with isolated phrenic neuritis or neuralgic amyotrophy syndrome (77.3%). They had right-sided (45.5%) or bilateral (54.5%) phrenic involvement. Near-fatal drowning occurred in 18.2% (4/22) with persons needing assistance to be rescued following diving into water. Dyspnea with water immersion was the only symptom in 4.5% (1/22), and the presenting respiratory symptom in 36.4% (8/22). None had isolated left phrenic involvement. A range of electrophysiological, sonographic and pulmonary function test abnormalities including mild abnormalities were seen and not found to be significantly different to patients in whom water induced dyspnea was not recorded.

Respiratory distress with water immersion activities is a serious complication of phrenic neuropathies. Physician documented counseling is lacking. Isolated phrenic neuritis, neuralgic amyotrophy, right sided and bilateral phrenic involvement are most commonly implicated, but the range of severity and testing abnormalities suggests all neuralgic amyotrophy and phrenic neuropathy patients should be warned especially about diving into water.