Chills: Causes, Assessment & Nursing Guide
⚡ Quick Clinical Snapshot
- Serial vitals with accurate fever assessment—compare to baseline and note timing with chills
- Perfusion and mental status: capillary refill, skin temperature, confusion or somnolence
- Focus for source: lungs, abdomen, skin/wounds, urine, lines and devices, recent procedures
- Intake/output, antipyretics given, cultures or labs drawn per order—track trends, not single values
- Hypotension, tachycardia, tachypnea, or hypoxia with chills—think sepsis pathways until evaluated
- Rigors during or immediately after a blood product or infusion—stop per protocol and notify
- New murmur with fever and systemic symptoms—urgent evaluation for endocarditis concern
- Altered consciousness, stiff neck, or petechial rash with fever—emergent escalation per policy
- Severe flank pain, dysuria, or catheter dysfunction with rigors—possible urosepsis
- Immunocompromise or neutropenia with any new chills—lower threshold for escalation
- Rising early warning score or sustained tachycardia with suspected infection
- Oliguria, mottled skin, or lactate elevation when measured—per sepsis bundle
- Recurrent rigors despite antipyretics or worsening focal symptoms
- Neonatal or young infant with poor feeding, lethargy, or tachypnea—pediatric pathways
- Obstetric patient with fever, uterine tenderness, or fetal concern—obstetric review
Few shifts pass without someone mentioning chills. The useful question is what pattern the complaint travels with—onset, associated signs, and trajectory—not a label in isolation.
Use the sections below to prioritize assessment, documentation, and escalation.
What Are Chills?
Chills describe a subjective feeling of cold with involuntary shivering or teeth chattering. Rigors are intense, sometimes violent, shaking episodes that often occur as body temperature rises—patients may say they “cannot stop shaking.”
Chills are common with systemic infection and fever, but the same sensation may be associated with transfusion reactions, drug fever, malignancy-related inflammatory states, autoimmune flares, hypoglycemia, or environmental cold exposure. A chill is not a diagnosis; it is a cue to pair subjective report with objective vitals, risk context, and trajectory.
Patients rarely separate “chills” from “rigors” precisely. Document their words, then add what you see (shivering, color, diaphoresis) and what you measure (temperature curve, hemodynamics). Trends beat a single snapshot.
Common Causes of Chills
The patterns below are teaching categories—not an exhaustive list. Licensed clinicians determine cause and treatment after history, exam, and investigations.
Related symptoms often assessed alongside this topic include High Fever, Low-Grade Fever, and Feverish Feeling.
- Infectious illnesses: Respiratory viruses such as influenza (flu), pneumonia, urinary or intra-abdominal infection, and bloodstream infection may be associated with chills and fever—source identification requires evaluation.
- Systemic inflammatory response: Chills can accompany a rising temperature set-point; severity ranges from self-limited viral illness to life-threatening sepsis when perfusion and organ function decline.
- Infusion- and procedure-related reactions: Blood products, IV medications, or contrast may trigger rigors or warmth with hypotension—follow transfusion and medication administration protocols.
- Non-infectious fever: Drug fever, malignancy, autoimmune disease, pulmonary embolism, and other conditions may be associated with rigors; avoid anchoring on infection alone when the story does not fit.
- Benign thermoregulation: After cold exposure or vigorous cooling measures, shivering can be protective—still verify mentation and perfusion in frail or high-risk patients.
Presentation Patterns
ED / Urgent care
- Acute rigors with measured fever and focal symptoms (cough, dysuria, abdominal pain) prompting evaluation for source and severity
- Chills with hypotension or hypoxia—prioritize resuscitation, monitoring, and sepsis recognition tools
- Travel, animal exposure, or tick history that may shift differential toward region-specific infections—document and communicate
General ward / Medical–surgical
- New-onset chills in a patient with lines, drains, or recent surgery—consider device-related or surgical-site infection in the broader assessment
- Intermittent rigors on the chemotherapy or immunotherapy unit—may overlap with drug reactions or neutropenic fever pathways per protocol
ICU and step-down
- Rigors during or after transfusion or large-volume resuscitation—time-stamp interventions and notify per protocol
- Ventilated patients: chills may be masked by sedation; rely on temperature trends, vasopressor need, and culture data
Outpatient / Primary care
- Classic viral prodrome: myalgias, headache, chills, then fever—education on return precautions and symptom trajectory
- Chronic recurrent night symptoms may overlap with other causes; avoid dismissing persistent systemic symptoms without follow-up planning
Common Signs and Symptoms Nurses Observe
- Patient reports feeling cold, “shaking,” or unable to warm up despite blankets
- Visible shivering, jaw tremor, or generalized muscle fasciculations
- Piloerection, pallor, then flushing as the episode evolves; diaphoresis when fever breaks
- Tachycardia and elevated temperature (or paradoxical hypothermia in some high-risk presentations)
- Myalgias, fatigue, headache, or arthralgias clustered with systemic illness
- Overlapping night sweats or drenching sweats as illness evolves—document timing
- Hypotension or widened pulse pressure when infection progresses—watch perfusion
Bedside Interpretation
Link observations to risk and trajectory—avoid naming a single disease at the bedside.
| Finding | Clinical interpretation (non-diagnostic) |
|---|---|
| Chills with focal lung findings and hypoxia | May be associated with pneumonia or other respiratory infection—escalate evaluation and oxygen therapy per protocol |
| Rigors with suprapubic pain, dysuria, or catheter issues | Raises concern for urinary tract source; may progress to urosepsis—track vitals and urine output |
| Chills during or immediately after infusion | May be associated with infusion or transfusion reaction, line contamination, or drug fever—stop per protocol, preserve access, notify promptly |
| Chills with rising inflammatory markers such as CRP and clinical deterioration | Supports systemic inflammatory state; correlate with cultures and examination—does not replace clinical judgment |
| Chills with clear lungs and benign exam but persistent tachycardia | Remain cautious—occult intra-abdominal, soft tissue, or line infection still possible; reassess rather than reassuring prematurely |
| Elderly patient with subtle confusion and “just not right” plus possible low-grade temperature | May be associated with serious infection with blunted fever—use early warning scores and low threshold for escalation |
Subtle Cues
- Patient requests extra blankets while core temperature is already rising—early chill phase
- Teeth chattering before numeric fever appears—repeat temperature on a schedule, not once
- Resting heart rate climbing across assessments without clear explanation
- Reduced oral intake or new confusion in a previously baseline patient—easy to attribute to fatigue; think infection until assessed
- Isolated rigor without measured fever after antipyretic—do not dismiss sepsis risk on temperature alone
In immunosuppression, older age, or beta-blockade, fever may be blunted while infection advances. Chills plus behavioral change or hemodynamic drift still warrant structured escalation.
When rapid escalation matters versus watchful care
| Presentation pattern | Likely considerations (examples) | Priority |
|---|---|---|
| Rigors with hypotension, tachypnea, hypoxia, or confusion | Sepsis, severe infection, or shock—among other causes of instability | Emergency—sepsis pathways and resuscitation per protocol |
| Chills with focal lung findings and productive cough | May be associated with pneumonia or other respiratory infection—requires evaluation | Urgent—oxygen, monitoring, medical review |
| Rigors during transfusion or shortly after medication bolus | Transfusion reaction, infusion reaction, or line-related event | Emergency/urgent—stop infusion per protocol, continuous monitoring |
| Self-limited chills with viral symptoms and stable vitals between episodes | Uncomplicated viral illness—still provide return precautions | Routine/urgent—follow disposition and safety-netting |
Patient Population Differences
Infants and children
- Young children may not say “chills”; look for shaking, color change, fussiness, or refusing to drink.
- Fever in neonates is handled with specific pediatric protocols—maintain a low threshold for senior review.
Older adults
- Blunted fever response is common; chills with mild temperature change can still reflect serious bacteremia.
- New confusion, falls, or reduced oral intake may be the leading clues rather than classic rigors.
Pregnancy and postpartum
- Fever with uterine tenderness, malodorous lochia, or fetal tachycardia requires obstetric escalation.
- Physiologic flushing occurs; pair subjective chills with objective trends and fetal wellbeing when applicable.
Immunocompromise and oncology
- Neutropenic fever pathways may apply—chills can be the first signal before numeric fever peaks.
- Central lines and chemo ports change the infection risk profile; inspect sites and ask about flushing pain.
Red-Flag Features Requiring Urgent Action
- Hypotension, tachycardia, tachypnea, hypoxia, or altered mental status with suspected infection—activate sepsis pathways per facility policy
- Rigors with new murmur, peripheral stigmata of endocarditis, or septic emboli—urgent medical evaluation
- Petechial or purpuric rash with fever—emergent evaluation for meningococcemia and related emergencies per protocol
- Severe headache, neck stiffness, or photophobia with fever—do not attribute to “just a chill”
- Postpartum fever with uterine pain, foul lochia, or hemodynamic change—obstetric emergency considerations
- Neonatal or young infant with temperature instability, poor feeding, or apnea—pediatric escalation thresholds
Vitals-first assessment and trend review
ABCs and perfusion
- Airway and work of breathing if hypoxic or fatigued; supplemental oxygen per protocol
- Circulation: BP, HR, capillary refill, urine output, lactate when ordered—sepsis thinking when features align
Temperature technique and timing
- Use consistent site and device; repeat after rigors when feasible—single afebrile reading does not rule out infection
- Record antipyretic times before interpreting temperature curves
Focused source survey
- Lungs, abdomen, skin and wounds, joints, urine symptoms, throat, sinuses, and device sites
- Recent travel, sick contacts, animal exposures, sexual history when relevant to institutional policy
- Early warning or sepsis screening tools per facility—document score and actions taken
Immediate Non-Pharmacological Nursing Interventions
Comfort and thermoregulation
- Offer warm blankets during chill phase; anticipate diaphoresis as fever breaks and change linens to protect skin
- Encourage oral fluids when appropriate; monitor intake if NPO or at risk of AKI
Monitoring and access
- Establish or verify IV access when instability is suspected; prepare labs and cultures per order
- Continuous or frequent vitals during rigors and after antipyretics—watch for delayed hypotension
Escalation and isolation
- Notify provider for red flags; initiate sepsis bundle elements you are authorized to perform
- Apply transmission-based precautions when indicated while awaiting definitive diagnosis—follow infection control
Nursing Documentation Focus
Key elements
- Patient-reported words in quotes; onset, duration, and whether shaking was localized or generalized
- All vitals with times; temperature site; SpO₂; antipyretics given; I&O when relevant
- Lines, infusions running, recent blood products, procedures, and travel or exposure history if collected
- Screening scores, notifications, cultures obtained, and response to nursing measures
Example nursing note
“0315: Pt reports ‘shaking so hard the bed moves.’ T 38.9°C oral (0300: 37.2°C). HR 118 bpm, BP 98/62 mmHg, RR 26/min, SpO₂ 93% RA. Appears flushed, visibly shivering; peripheral pulses palpable. Lung auscultation coarse R base per RN; denies dysuria. 2 L O₂ started per protocol; blood cultures x2 drawn 0325 per order; lactate sent. 500 mL bolus running; provider updated at 0330. Will repeat vitals q15 min; sepsis screen documented.”
How This Symptom May Progress
- Uncomplicated viral illness: chills and fever may peak over hours to a day, then improve with supportive care
- Bacterial infection without treatment: rising temperature, tachycardia, and systemic symptoms may evolve toward sepsis
- Transfusion reaction: symptoms may begin during infusion and escalate rapidly—protocol-driven response is time-sensitive
- Occult abscess or endocarditis: intermittent rigors with nonspecific malaise—requires clinician-directed workup
When chills repeat after transient improvement, ask whether a new source has appeared (line, wound, urine) or whether inadequate source control is evolving. Pair the story with objective trends—not a single temperature.
Escalation Criteria
Escalation prioritizes infection severity, hemodynamic stability, and high-risk hosts.
- Hypotension, MAP below threshold per protocol, or escalating vasopressor need
- SpO₂ below target despite oxygen or new requirement for high-flow support
- Altered consciousness, seizure, or signs of meningitis
- Suspected transfusion reaction with instability—follow emergency transfusion reaction steps
- Persistent tachycardia or rigors with focal infection signs and inadequate oral intake
- Neutropenic or immunocompromised patient with new chills—even if fever is not yet documented
- Stable viral symptoms with agreed return precautions; document specific symptoms that should prompt earlier reassessment
Early escalation when chills cluster with perfusion or respiratory compromise supports timely source control and treatment—documentation of the pattern helps the whole team.
💡 Clinical Pearls
- Rigors plus hypotension should trigger sepsis thinking before the labs return—act on the bedside picture.
- Ask about the last transfusion, new antibiotic, or line manipulation—timing links to cause more often than people expect.
- In older adults, “feeling cold” with confusion may be sepsis even without impressive fever—use early warning scores.
- Avoid labeling a patient “just viral” when vitals are trending wrong; reassess rather than anchoring on the first impression.
Emergency search phrases patients use (intake cues)
These phrases reflect common patient search language (plain-language intent), including seriousness, urgency, and when-to-seek-care queries that often accompany symptom searches. This block is written for clinicians and nurses: use it to guide history-taking, anticipate concerns, and align education—not as direct answers to give patients verbatim.
| Patient question (search language) | How to use this in practice (staff) |
|---|---|
| How fast do symptoms progress? | Maps to timeline, trajectory, and repeat vitals; document change over minutes or hours. |
| What should I do while waiting for help? | Structure safety messaging within scope: airway positioning, emergency services, monitoring, nil by mouth when relevant. |
| Could this be a heart attack or a clot? | Expect cardiac and VTE fears; pair with objective monitoring and pathway language—avoid false reassurance. |
| When is calling an ambulance appropriate? | Align with escalation criteria; document advice given per local protocol. |
| Should I drive myself to the hospital? | Reinforces transport safety and severity thresholds. |
| What will the ER do first? | Sets expectations for ABCs, monitoring, access, and initial tests—helps nursing education match actual flow. |
Frequently Asked Questions (FAQ)
1. Are chills always caused by infection?
No. Chills may be associated with infection and fever, but similar sensations can occur with drug fever, transfusion reactions, malignancy-related fever, autoimmune flares, and other inflammatory states. Nurses document timing, associated vitals, lines and infusions, and escalate per protocol rather than assuming a single cause.
2. What is the difference between chills and rigors?
Patients often use the words interchangeably. In practice, rigors describe pronounced, sometimes violent, shaking that may mark the chill phase of a fever spike. Both warrant objective temperature measurement, vital sign trends, and assessment for sepsis when features are concerning.
3. When should chills prompt urgent sepsis evaluation?
When chills occur with hypotension, tachycardia, tachypnea, hypoxia, altered mental status, oliguria, new hypothermia in a high-risk patient, or a suspected infected focus in an immunocompromised host—follow facility early warning and sepsis screening tools and escalate promptly.
4. Can someone have chills without a documented fever?
Yes. Timing of temperature checks, antipyretics, baseline immunosuppression, or peripheral vasoconstriction can limit fever detection. Do not dismiss chills solely because one temperature is normal—repeat assessment, consider core temperature methods when appropriate, and track trends.
5. What should nurses document when a patient reports chills?
Quote the patient words, onset and duration, severity, associated symptoms, recent procedures and lines, all vitals with times, antipyretics given, intake and output when relevant, screening scores completed, notifications, and response to nursing measures—avoid stating a definitive diagnosis.
6. Are there pediatric-specific considerations?
Infants and young children may show feeding change, irritability, lethargy, or tachypnea rather than saying they feel cold. Neonates can present with nonspecific instability; maintain a low threshold for escalation per pediatric early warning systems and institutional policy.
References
[1] National Institute for Health and Care Excellence. Fever in under 5s: assessment and initial management. Clinical guideline (check current update). https://www.nice.org.uk/guidance/ng143
[2] National Institute for Health and Care Excellence. Sepsis: recognition, diagnosis and early management (check current update). https://www.nice.org.uk/guidance/ng51
[3] Centers for Disease Control and Prevention. Sepsis — clinical information and patient education (use current CDC pages). https://www.cdc.gov/sepsis/
[4] World Health Organization. Sepsis — overview and advocacy materials (regional materials may vary). https://www.who.int/news-room/fact-sheets/detail/sepsis
[5] Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-810. doi:10.1001/jama.2016.0287
[6] StatPearls Publishing. Fever. Treasure Island (FL): StatPearls Publishing; use current edition. https://www.ncbi.nlm.nih.gov/books/NBK554418/
[7] Evans SS, Repasky EA, Fisher DT. Fever and the thermal regulation of immunity: the immune system feels the heat. Nat Rev Immunol. 2015;15(6):335-349. doi:10.1038/nri3843
Disclaimer: This content is for informational and educational purposes only and is intended for nursing professionals and students. It supports assessment and communication; it does not replace medical diagnosis, prescribing decisions, or licensed clinician judgment. Nursing practice focuses on objective observation, trending, and escalation per protocol—not labeling a condition at the bedside. Clinical assessment requires correlation with history, examination, and diagnostic testing. This information does not replace clinical judgment, institutional protocols, or current evidence-based practice guidelines. Not medical advice. Always follow your facility’s specific policies and escalation procedures. No conflicts of interest to disclose.