Definition

1. Adjective:

   • Occurring every fourth day: Describes something, especially a fever or symptom, that recurs at intervals of approximately 72 hours (every fourth day, counting inclusively). This term is most historically associated with descriptions of malaria.

2. Noun:

   • A malarial fever that recurs every fourth day: A specific type of malarial paroxysm characterized by fever peaks occurring at roughly 72-hour intervals, typically caused by the Plasmodium malariae parasite.

Usage Examples

• Adjective:

  • The patient experienced quartan fevers, with severe chills every fourth day.
  • Historically, physicians distinguished quartan ague from other periodic fevers.

• Noun:

  • He was diagnosed with a quartan, which indicated infection with *Plasmodium malariae.*
  • Before modern medicine, a persistent quartan could last for many years.

Advanced Usage

• Medical/Historical Context: The term is primarily used in historical or specialized medical texts describing the periodicity of diseases, especially classical forms of malaria. The cycle is "quartan" because the fever occurs on day one, is absent on days two and three, and returns on day four.
• "Double quartan": A historical term for a more complex fever pattern with overlapping cycles, suggesting a mixed infection.

Variants and Related Words

• Quartan fever: (Noun phrase) Synonymous with the noun definition, a fever recurring every fourth day.
• Quartan ague: (Noun phrase, archaic) An older term for quartan malaria, where "ague" refers to a fever with chills.

Synonyms

• Fourth-day: (Adjective) Descriptive synonym for the recurring interval.
• Malariae malaria: (Noun) The modern clinical term for the disease caused by , which produces a quartan fever pattern.

Notes on Meaning

• The "fourth day" is counted inclusively in the traditional medical sense: if a fever occurs on Monday, the next episode is on Thursday (Monday=day 1, Tuesday=day 2, Wednesday=day 3, Thursday=day 4).
• In contemporary medicine, the specific parasite name () is used more frequently than the term "quartan," which remains a descriptive term for the fever's timing.

Adjective

1. occurring every fourth day (especially the fever and weakness of malaria)
   • quartan malaria

Noun

1. a malarial fever that recurs every fourth day