What are the different fever patterns (continuous, remittent, intermittent, biphasic, quotidian, tertian, relapsing, low‑grade) and the diseases that exemplify each?

Types of Fever Patterns and Their Clinical Examples

Fever patterns have limited diagnostic utility in modern clinical practice, with the notable exception of quotidian fever in Adult-Onset Still's Disease (AOSD) and the brief 1-3 day episodes characteristic of Familial Mediterranean Fever (FMF). 1, 2, 3

Major Fever Pattern Categories

Continuous (Sustained) Fever

• Definition: Persistent elevation with minimal variation (<1°C) over 24 hours 4, 5
• Classic examples:
  • Gram-negative pneumonia 1
  • Central nervous system damage 1
  • Typhoid fever (enteric fever) in early stages 2
• Clinical note: While sustained fever nearly always occurred in patients with Gram-negative pneumonia or CNS damage, some patients with these diseases had other patterns as well 1

Remittent Fever

• Definition: Temperature fluctuates daily but never returns to normal, with variations >1°C 4, 5
• Most common pattern: This is the predominant fever pattern observed in clinical practice, typically following diurnal variation when due to infection 1
• Examples:
  • Most bacterial and viral infections 1
  • Respiratory tract infections 2
  • Acute diarrheal diseases 2

Intermittent Fever

• Definition: Temperature returns to normal daily, with fever spikes separated by afebrile periods 4, 5
• Examples:
  • Malaria (with specific periodicity patterns - see below) 2
  • Pyogenic infections 1
  • Abscesses 1

Quotidian Fever

• Definition: Daily fever spikes, typically occurring once every 24 hours 2
• Pathognomonic example: Adult-Onset Still's Disease (AOSD) - fever >39°C, intermittent pattern lasting >1 week is a major diagnostic criterion 2
• Differential consideration: Familial Mediterranean Fever does NOT have quotidian pattern; episodes last 1-3 days 2, 3

Tertian Fever

• Definition: Fever spikes occurring every 48 hours (on days 1 and 3) 5
• Classic example: Plasmodium vivax and P. ovale malaria 5
• Mechanism: Corresponds to erythrocytic schizogony cycle 5

Quartan Fever

• Definition: Fever spikes every 72 hours (on days 1 and 4) 5
• Classic example: Plasmodium malariae infection 5

Relapsing/Periodic Fever

• Definition: Recurrent fever episodes with complete resolution between attacks 2, 3
• Key examples:
  • Familial Mediterranean Fever (FMF): Brief episodes lasting 1-3 days, does NOT follow quotidian pattern 2, 3
  • TRAPS (TNF Receptor Associated Periodic Syndrome): Longer episodes averaging 21 days 2
  • PFAPA syndrome: Periodic fever with aphthous stomatitis, pharyngitis, and adenitis 6
  • AOSD polycyclic pattern: Recurrent flares with complete remission between episodes, may be years apart 2

Hectic (Septic) Fever

• Definition: Wide daily temperature swings (>1.4°C) with dramatic fluctuations 1, 4
• Clinical significance: Although more frequently seen in bacteremic patients, this pattern has poor diagnostic specificity - many nonbacteremic subjects had hectic fever, and many bacteremic patients lacked this pattern 1
• Examples:
  • Septicemia/bacteremia 2
  • Abscesses 1
  • Tuberculosis 2

Biphasic Fever

• Definition: Two distinct fever peaks separated by an afebrile interval 5
• Examples:
  • Dengue fever (classic "saddleback" pattern) 2, 5
  • Leptospirosis 2, 5
  • Some viral hemorrhagic fevers 2

Low-Grade Fever

• Definition: Persistent mild temperature elevation, typically 37.5-38.3°C 7, 8
• Examples:
  • Tuberculosis 2
  • Subacute bacterial endocarditis 5
  • Chronic viral infections (HIV, hepatitis) 2
  • Neoplastic diseases 2

Critical Clinical Caveats

Limited Diagnostic Value

• Most fever patterns lack clinical significance: Prospective studies of 200 consecutive patients showed that fever patterns (except sustained fever in specific conditions) are not diagnostically helpful 1
• Pattern overlap is extensive: Hectic fevers occurred in patients with all categories of infectious and noninfectious diseases 1

Diurnal Variation Considerations

• Body temperature varies significantly throughout the day, with implications for fever detection 8
• The likelihood of detecting fever varies by time of day, patient age, and sex 8
• Approximately 50% of patients with undifferentiated fever may be afebrile at presentation despite clear fever history 7

Geographic and Travel Context

• In returning travelers, malaria (22.2% of tropical infections) and dengue (5.2%) are the most common tropical causes of fever 2
• Enteric (typhoid) fever accounts for 2.3% of febrile illnesses in travelers 2
• Respiratory tract infections (13.5%) and acute diarrheal disease (13.6%) are the most common non-tropical causes 2

Specific Pattern Recognition

• AOSD quotidian fever: Fever >39°C with intermittent pattern >1 week is a major Yamaguchi criterion (93.5% sensitivity) 2
• FMF episodes: Last 1-3 days with marked elevation of acute phase reactants, respond to colchicine 2, 3
• TRAPS: Fever attacks average 21 days with ocular involvement 2