What could be causing a fluttering sensation in the right upper abdomen?

Fluttering Sensation in Right Upper Abdomen

Most Likely Diagnosis

A fluttering sensation in the right upper abdomen is most commonly caused by diaphragmatic flutter (also called "belly dancer syndrome"), a rare neurological disorder characterized by involuntary, rhythmic contractions of the diaphragm at frequencies of 9-15 Hz, which can present with epigastric pulsations, abdominal wall movements, and upper abdominal discomfort. 1, 2

However, you must first exclude biliary pathology with right upper quadrant ultrasound, as this is the standard initial imaging for any RUQ symptoms and can identify life-threatening conditions like acute cholecystitis. 3, 4

Immediate Diagnostic Algorithm

Step 1: Obtain Right Upper Quadrant Ultrasound First

• The American College of Radiology rates RUQ ultrasound as 9/9 (usually appropriate) for any right upper quadrant symptoms and should be performed immediately as first-line imaging. 3, 4
• Ultrasound has 96% accuracy for detecting gallstones and can identify acute cholecystitis with 88% sensitivity and 80% specificity. 3
• Look specifically for: gallstones, gallbladder wall thickening (>3mm), pericholecystic fluid, bile duct dilatation, and sonographic Murphy sign. 3

Step 2: If Ultrasound is Negative, Consider Diaphragmatic Flutter

• Diaphragmatic flutter presents with visible undulating abdominal wall movements, often rhythmic, that may be accompanied by upper abdominal or lower chest discomfort. 5, 1, 2
• High-frequency diaphragmatic flutter (9-15 Hz) can cause chronic symptoms including esophageal belching, hiccups, retching, and epigastric pulsations without respiratory distress. 1
• Classic diaphragmatic flutter (0.5-8.0 Hz) typically presents with dyspnea and respiratory distress in addition to abdominal movements. 1

Step 3: Confirm Diaphragmatic Flutter with Specific Testing

• Electromyography (EMG) of the diaphragm, scalene, and parasternal intercostal muscles showing repetitive discharges at 9-15 Hz establishes the diagnosis. 1
• Spirographic tracings showing high-frequency oscillations (9-15 Hz) superimposed on normal tidal respiratory movements confirm the diagnosis. 1
• Diaphragmatic fluoroscopy can visualize the high-frequency flutter movements directly. 5

Treatment for Diaphragmatic Flutter

Carbamazepine 200-400 mg three times daily is the first-line treatment and leads to disappearance or significant improvement of flutter and clinical symptoms. 1

• Alternative treatments include oral diazepam for symptomatic relief. 2
• In refractory cases not responding to medical therapy, phrenic nerve crush may be considered. 5

Critical Differential Diagnoses to Exclude

Biliary Pathology (Must Rule Out First)

• Acute cholecystitis presents with RUQ pain, Murphy's sign, fever, and abdominal tenderness—ultrasound is mandatory to exclude this. 3
• Biliary colic can be triggered by increased intra-abdominal pressure during Valsalva maneuvers and may present with intermittent RUQ sensations. 4

Functional Gastrointestinal Disorders

• Functional abdominal bloating and distension can cause sensations of trapped gas, abdominal pressure, and fullness in the upper abdomen. 6
• These symptoms commonly coincide with irritable bowel syndrome, functional dyspepsia, or functional constipation. 6

Hepatic Flexure Pathology

• Colonic distension or inflammation at the hepatic flexure can cause referred RUQ sensations, particularly if triggered by bowel movements. 4

Important Clinical Pitfalls

• Do not skip ultrasound and proceed directly to neurological workup—missing acute cholecystitis can be life-threatening. 3
• The sonographic Murphy sign has relatively low specificity and is unreliable if the patient received pain medication prior to imaging. 3
• Diaphragmatic flutter is frequently misdiagnosed due to its rarity and variable presentations, often leading to extensive unnecessary workup. 2
• If the patient has visible abdominal wall movements, directly observe and document the frequency and pattern—this clinical finding is pathognomonic for diaphragmatic flutter. 5, 1
• CT abdomen should not be ordered as initial imaging for RUQ symptoms unless the patient is hemodynamically unstable—ultrasound is more appropriate and avoids unnecessary radiation. 4