Intermittent Fluttering Under Right Inframammary Fold
Most Likely Diagnosis
The intermittent fluttering sensation under the right inframammary fold is most likely diaphragmatic flutter, a rare disorder characterized by involuntary rhythmic contractions of the diaphragm that can present as visible or palpable abdominal/chest wall movements. 1, 2
Clinical Presentation and Diagnosis
Diaphragmatic flutter typically manifests as abnormal abdominal or chest wall movements, often described as pulsations or fluttering sensations, and may be accompanied by dyspnea, thoracic or abdominal wall pain, or epigastric pulsations 1, 2
The condition involves involuntary contractions of the diaphragm with frequencies ranging from 0.5-8.0 Hz in classic cases, though higher frequency variants (9-15 Hz) have been documented 2
Diagnosis is confirmed through electromyography (EMG) of the diaphragm showing repetitive high-frequency discharges, and spirographic tracings demonstrating oscillations superimposed on normal tidal respiratory movements 2, 3
Diaphragmatic fluoroscopy can directly visualize the high-frequency flutter movements and confirm the diagnosis 1
Differential Considerations
While cardiac atrial flutter could theoretically cause chest sensations, it would not produce a localized fluttering sensation specifically under the inframammary fold and would be accompanied by palpitations, dizziness, or other systemic symptoms 4, 5
The anatomical location (right inframammary fold) and intermittent nature strongly suggest a diaphragmatic rather than cardiac origin 1, 2
Treatment Approach
First-line pharmacological treatment is carbamazepine 200-400 mg three times daily, which has demonstrated effectiveness in eliminating or significantly improving both the flutter and associated symptoms 2
Alternative Treatment Options
If carbamazepine is ineffective or not tolerated, noninvasive ventilatory support (NVS) can be attempted, as diaphragm rest has been shown to instantaneously halt flutter episodes 6
Mouthpiece or nasal NVS can be used intermittently when symptoms occur, with episodes typically resolving within 40 minutes of application 6
Phrenic nerve crush is a surgical option reserved for highly symptomatic patients refractory to medical management, though success rates are variable 1, 6
Critical Pitfalls to Avoid
Do not dismiss this as a benign fasciculation without proper diagnostic workup, as untreated diaphragmatic flutter can cause significant respiratory distress and chronic pain 1, 2
Avoid attributing symptoms to cardiac causes without appropriate cardiac evaluation if the patient has risk factors for arrhythmias, though the localized nature makes this less likely 1
The psychosomatic component may participate in symptom development, but this does not negate the need for specific treatment of the underlying neuromuscular disorder 3
Diagnostic Workup Algorithm
Obtain detailed history focusing on: timing of episodes, triggers (deep breathing, position changes), associated respiratory symptoms, and any neurological history including prior stroke 1, 6
Perform diaphragmatic EMG as the gold standard diagnostic test to document high-frequency repetitive discharges 2, 3
Consider diaphragmatic fluoroscopy for direct visualization if EMG is unavailable or inconclusive 1
Obtain spirographic tracings to identify characteristic high-frequency oscillations superimposed on normal breathing patterns 2