What causes hiccups in a patient?

What Causes Hiccups

Hiccups result from involuntary spasmodic contractions of the diaphragm and intercostal muscles followed by sudden glottic closure, triggered by irritation anywhere along a complex reflex arc involving peripheral (phrenic, vagal, sympathetic) and central (brainstem) pathways. 1, 2

Pathophysiology

Hiccups occur when any disruption affects the reflex arc between peripheral receptors and the brainstem 3, 2. The mechanism involves:

• Sudden diaphragmatic and intercostal muscle contraction followed immediately by laryngeal closure, producing the characteristic "hic" sound 4, 2
• Reflex arc components: peripheral phrenic nerve, vagus nerve, sympathetic pathways, and central midbrain modulation 2

Common Causes by Category

Gastrointestinal Causes (Most Common)

• Gastroesophageal reflux disease (GERD) is the most common cause of persistent hiccups 3, 5
• Gastric distention, gastric and duodenal ulcers, gastritis, and esophagitis 5
• Inflammatory bowel diseases and celiac disease 6

Cardiovascular Causes

• Pericarditis and pericardial effusion compressing the phrenic nerve 1, 6
• Myocardial infarction 5

Central Nervous System Causes

• Brain tumors and traumatic brain injury 1
• Stroke and space-occupying lesions 2

Medication-Induced Causes

• Opioids (morphine, fentanyl, tramadol) can cause persistent hiccups through unclear mechanisms 4
• Mycophenolate mofetil, propofol, beta-blockers 6
• Anti-parkinsonism drugs, anesthetic agents, steroids, and chemotherapy agents 2

Other Peripheral Causes

• Mediastinal lesions and post-surgical complications 6
• Vocal cord dysfunction and ear problems affecting the vagus nerve 6
• Renal failure, prostate cancer, abdominal surgery 5
• Herpes infection 2

Psychogenic Causes

• Anxiety disorders and stress can contribute to hiccups 7

Clinical Significance

Persistent hiccups (>48 hours) or intractable hiccups (>2 months) should prompt investigation for underlying pathology 2, 5. Untreated persistent hiccups can lead to:

• Weight loss 1, 5
• Depression 1, 5
• Sleep deprivation 5

Diagnostic Approach

When evaluating persistent hiccups:

• Detailed medical history and physical examination focusing on the reflex arc pathway 5
• Upper gastrointestinal investigations (endoscopy, pH monitoring, manometry) should be included systematically given GERD's prevalence 5
• Chest imaging (X-ray, CT scan) to rule out mediastinal pathology 6
• Echocardiography if pericardial effusion is suspected 1
• Consider brain imaging for central causes if indicated 2