Hiccups (Singultus) — Ward Management

Definition & Classification

Pathophysiology

• Afferent: phrenic nerve, vagus nerve, thoracic sympathetic chain
• Centre: brainstem (independent of rhythmic breathing pathways)
• Efferent: phrenic nerve → diaphragm

Causes to Consider in the Ward

• Gastric distension (food, carbonated drinks, air)
• Alcohol ingestion
• Abrupt change in temperature
• Excessive smoking
• Psychogenic

Tip: Check the ear canal in every patient with unexplained persistent hiccups — a hair is an easily corrected cause. Ask if hiccups resolve during sleep: resolution suggests a psychogenic component.

Step 1 — Physical / Non-pharmacological Manoeuvres

• Swallow a teaspoon of dry granulated sugar — as effective as any other method
• Sip or rapidly drink ice-cold water
• Breath-holding / Valsalva manoeuvre
• Rebreathing into a paper bag (raises pCO₂)
• Nasopharyngeal stimulation (cotton-tipped swab at nasopharynx)
• Induced fright or distraction
• Digital pharyngeal stimulation
• Remove foreign body from ear if present

Step 2 — Pharmacological Management

First-line (FDA-approved)

Chlorpromazine is the only FDA-approved agent. Takes effect within ~30 minutes. Monitor for hypotension (especially IV) and extrapyramidal effects.

Second-line / Alternatives

Palliative care / refractory

• Amitriptyline — emerging evidence for refractory idiopathic intractable hiccups (PMID: 41348394)
• Drugs that promote gastric emptying (metoclopramide, domperidone) + antacids if GI trigger is suspected
• Phrenic nerve block — for truly intractable cases unresponsive to pharmacotherapy

Practical Ward Algorithm

Hiccups in ward patient
        ↓
Duration < 48 h?
  → YES: Physical manoeuvres (sugar, cold water, breath-holding)
           Remove ear foreign body if found
           Reassure and observe
  → NO (≥48 h): Investigate for cause
           ↓
     Check: ear canal, CXR, renal function, glucose, drug list (dexamethasone?)
           ↓
     First-line drug: Chlorpromazine 25–50 mg PO/IV
           ↓
     Not responding → Baclofen or Gabapentin (titrate up)
           ↓
     Intractable >1 month → specialist referral (neurology/gastroenterology)
                            Consider phrenic nerve block

Key Points for Ward Practice

1. Always check the drug chart — dexamethasone is a frequent culprit in oncology/ward patients.
2. Look in the ear — a simple hair removal can cure persistent hiccups.
3. Chlorpromazine IV causes hypotension; ensure IV access and have the patient supine; monitor BP.
4. Baclofen and gabapentin are preferred for long-term outpatient management due to better tolerability.
5. Hiccups persisting during sleep are less likely psychogenic — pursue organic work-up.
6. Lateral medullary (Wallenberg) syndrome and brainstem lesions must be excluded in new-onset intractable hiccups with any neurological signs.

• Tintinalli's Emergency Medicine, Ch. 62 (Tables 62-5, 62-6, 62-7)
• Adams and Victor's Principles of Neurology, 12th Ed., Ch. on Aberrant Respiratory Patterns
• Recent evidence: Pharmacotherapy for Chronic & Intractable Hiccups in Palliative Care [PMID: 41274322]; Perioperative hiccups narrative review [PMID: 40055925]; Amitriptyline for refractory idiopathic hiccups [PMID: 41348394]

Shivering Without Fever — Clinical Guide

Physiology of Shivering

Key distinction: Fever = elevated set-point (pyrogen-driven), with shivering/chills as the rising phase. Shivering without fever = normal or low set-point, with actual or perceived heat loss.

Causes of Shivering Without Fever

1. Hypothermia / Environmental Cold

• Exposure to cold ambient temperature
• Cold IV fluids or blood products administered rapidly
• Post-operative state (see below)
• Wet clothing/bedding, poor insulation in the elderly

2. Post-Anaesthetic / Post-Procedural Shivering

• Heat redistribution from core → periphery during anaesthesia
• Anaesthetics (volatiles, spinal, epidural) suppress the normal vasoconstrictive response to cold
• Differential CNS recovery: spinal cord recovers before the cortex → uninhibited spinal clonic reflexes
• Remifentanil withdrawal → NMDA receptor stimulation → shivering independent of temperature

3. Sepsis / Bacteraemia (Rigors)

• Rigors are severe paroxysmal shivering that can precede the fever spike by 30–60 minutes
• A ward patient shivering with no current fever may be in the pre-febrile phase of sepsis
• Must always be considered and excluded

4. Transfusion Reactions

• Febrile non-haemolytic transfusion reaction (FNHTR): shivering ± mild fever during/after blood transfusion
• Haemolytic transfusion reaction: shivering, flank pain, haemoglobinuria — can be afebrile early on

5. Drug / Contrast Reactions

• Amphotericin B infusion: classic rigors (shaking chills) without sustained fever
• IV contrast media reactions
• Drug allergy reactions
• Vancomycin — associated with rigors during infusion

6. Hypoglycaemia

• Catecholamine surge from hypoglycaemia can produce shivering, diaphoresis, tremor
• Check bedside glucose in any unexplained shivering episode

7. Anxiety / Panic / Psychogenic

• Hyperventilation and anxiety can produce shivering-like tremors
• Diagnosis of exclusion

8. Neurological Causes

• Unilateral shivering, particularly in the context of a deep intracerebral haemorrhage or brainstem lesion
• Lateral medullary syndrome can affect thermoregulation

9. Thyroid Storm / Endocrine

• Thyrotoxicosis: increased metabolic activity with shivering, tachycardia, diaphoresis
• Hypoadrenalism / Addisonian crisis: can present with shivering

10. Haemorrhage / Shock

• Sympathetic activation and peripheral vasoconstriction in hypovolaemic shock can cause shivering even without fever

Consequences of Shivering (Why It Matters)

Assessment in the Ward

1. Temperature — rectal/tympanic (most accurate); axillary underestimates
2. Blood glucose — exclude hypoglycaemia
3. SpO₂ and HR — shivering raises demand; watch for tachycardia
4. Recent history: surgery/procedure, blood transfusion, IV drug infusion, contrast exposure
5. Blood cultures if sepsis suspected — before starting antibiotics
6. Check IV lines for site of infusion reactions

Management

Step 1 — Treat the Cause

Step 2 — Symptomatic Treatment of Shivering

Meperidine 12.5–25 mg IV is the first-line pharmacologic agent — it terminates shivering from any cause within minutes. The antishivering effect is disproportionate to its analgesic effect and appears mediated via α₂β-adrenoceptor, not κ-opioid receptors.

Mechanically Ventilated Patients

• Small dose of neuromuscular blocker (just enough to resolve shivering) while actively rewarming — used as a bridge in the ICU/PACU.

Summary Algorithm

Shivering without fever (ward patient)
         ↓
Immediate: O₂ supplementation + check glucose + temperature
         ↓
┌────────────────────────────────┐
│ Is the patient hypothermic?   │
│ (Temp < 36°C)                 │
└────────────────────────────────┘
     YES → Forced-air rewarmer + warm IV fluids
             → Meperidine 12.5–25 mg IV if intense
     NO  → Seek cause:
           • Post-anaesthetic? → Rewarm + meperidine
           • Pre-febrile sepsis? → Cultures + antibiotics
           • Transfusion reaction? → Stop transfusion
           • Drug/contrast reaction? → Stop infusion + antihistamine
           • Hypoglycaemia? → IV dextrose
           • Haemorrhage/shock? → Fluid resuscitation
           • Neurological? → Examine, consider imaging

• Costanzo Physiology, 7th Ed. — Thermoregulation and Shivering
• Miller's Anesthesia, 10th Ed. — Thermoregulation, Postoperative Hypothermia and Shivering
• Morgan and Mikhail's Clinical Anesthesiology, 7th Ed. — Shivering & Hypothermia
• Barash Clinical Anesthesia, 9th Ed. — Hypothermia and Shivering