What investigations should be done for a patient presenting with hiccups?

Investigations for Hiccups

The investigation approach for hiccups depends critically on duration: acute hiccups (<48 hours) rarely require any workup, while persistent (>48 hours) or intractable (>1 month) hiccups mandate a systematic search for underlying pathology that could impact morbidity and mortality. 1, 2

Initial Clinical Assessment

History and Physical Examination

The evaluation must focus on identifying potentially serious underlying causes rather than treating hiccups as a benign nuisance. Key historical elements include: 1, 2

• Duration of hiccups (acute vs. persistent vs. intractable) 1
• Medication history, particularly chemotherapy drugs, steroids, and CNS depressants 3, 2
• Gastrointestinal symptoms including dysphagia, odynophagia, reflux, or abdominal distension 1, 4
• Neurological symptoms such as headache, altered mental status, or focal deficits 1, 2
• Recent anesthesia or surgical procedures 5
• Infectious symptoms including fever, cough, or sore throat 6

Physical Examination Priorities

• Abdominal examination for distension, tenderness, or masses 1
• Neurological examination for focal deficits or signs of increased intracranial pressure 1, 2
• Cardiovascular examination for signs of pericarditis or myocardial disease 2, 5
• Neck examination for masses or thyroid abnormalities 1

Laboratory Investigations

For Persistent or Intractable Hiccups (>48 hours)

Initial laboratory workup should include: 3, 1, 2

• Complete blood count to assess for infection or hematologic malignancy 3, 2
• Comprehensive metabolic panel including electrolytes (sodium, potassium, calcium, magnesium), renal function (BUN, creatinine), and liver function tests 3, 1
• Fasting glucose or glycohemoglobin to evaluate for diabetes 3
• Thyroid-stimulating hormone to exclude thyroid dysfunction 3
• C-reactive protein as a marker of inflammation 3, 6
• Arterial blood gas if respiratory compromise is suspected 3
• Lactate and lactate dehydrogenase in systemically ill patients 6

Imaging Studies

Chest Radiography

Posteroanterior and lateral chest X-ray should be performed to evaluate for: 3, 1, 2

• Pulmonary pathology (pneumonia, mass, effusion)
• Mediastinal abnormalities
• Diaphragmatic elevation or pathology
• Cardiac silhouette enlargement

Computed Tomography

CT imaging is indicated when: 3, 6

• Chest CT if chest X-ray is abnormal or clinical suspicion for pulmonary embolism, mediastinal mass, or COVID-19 pneumonia exists 6
• Brain CT or MRI if neurological symptoms are present or examination is abnormal 1, 2
• Abdominal CT if intra-abdominal pathology is suspected 1

Electrocardiogram

12-lead ECG should be obtained to exclude: 3, 2, 5

• Myocardial infarction
• Pericarditis
• Arrhythmias
• QTc prolongation if antipsychotic treatment is being considered 3

Specialized Investigations

Upper Gastrointestinal Evaluation

Gastroesophageal reflux is a commonly overlooked cause of persistent hiccups. 4 Consider: 1, 4, 5

• Upper endoscopy (EGD) for patients with gastrointestinal symptoms or when other causes are excluded 4
• Abdominal ultrasound as initial imaging for gastric distension 1, 6
• Barium swallow is NOT recommended as it may delay other interventions 3

Additional Testing Based on Clinical Suspicion

• Echocardiography if structural heart disease or pericardial effusion is suspected 3, 2
• Holter monitoring if arrhythmia is a consideration 3
• COVID-19 testing in appropriate epidemiological context, especially with fever and respiratory symptoms 6
• Infectious workup including blood cultures if sepsis is suspected 1, 2

Critical Pitfalls to Avoid

Do not dismiss persistent hiccups as benign without investigation. They can herald serious conditions including: 1, 2, 5

• Pulmonary embolism 5
• Myocardial infarction 2, 5
• Central nervous system pathology 1, 2
• Malignancy (particularly hematologic or mediastinal) 2
• COVID-19 infection 6

Do not perform contrast swallow studies as they provide limited diagnostic value and delay definitive investigations. 3

Do not overlook gastroesophageal reflux as it may be substantially underestimated as a cause and responds well to treatment. 4

Investigation Algorithm Summary

For acute hiccups (<48 hours): No investigations needed unless associated with concerning symptoms. 1

For persistent hiccups (>48 hours): 1, 2

1. Complete blood count, comprehensive metabolic panel, thyroid function
2. Chest X-ray (PA and lateral)
3. 12-lead ECG
4. Consider upper endoscopy if gastrointestinal symptoms present

For intractable hiccups (>1 month) or red flag symptoms: 1, 2

1. All of the above
2. CT imaging (chest, brain, or abdomen based on clinical suspicion)
3. Echocardiography if cardiac disease suspected
4. Specialized testing based on findings (e.g., lumbar puncture, bronchoscopy)