Definition

1. Noun:
   • A historical epidemic disease: "sleepy sickness" refers to a specific type of encephalitis (inflammation of the brain) that was epidemic between approximately 1915 and 1926. Its medical name is encephalitis lethargica.
   • Characteristic symptoms: The disease is notably characterized by symptoms such as paralysis of the extrinsic eye muscles (leading to ophthalmoplegia), extreme muscular weakness, profound lethargy (sleepiness), and sometimes a Parkinson's disease-like state.

Usage Examples

• Noun:
  • The outbreak of sleepy sickness in the early 20th century puzzled doctors for years.
  • Patients with sleepy sickness often exhibited a mask-like face and severe lethargy.
  • Historical records describe the devastating effects of the sleepy sickness epidemic.

Advanced Usage

• Historical/Medical Context: The term is almost exclusively used in historical or medical discussions about the early 20th-century epidemic. It is not used for general sleepiness or modern illnesses.
  • The chapter on neurological history detailed the impact of sleepy sickness.

Variants and Related Words

• Encephalitis lethargica: The formal medical term for "sleepy sickness."
• Sleeping sickness: CRITICAL NOTE: This is a different disease. "Sleeping sickness" refers to African trypanosomiasis, a parasitic disease spread by tsetse flies. Do not confuse "sleepy sickness" with "sleeping sickness."

Synonyms

• Encephalitis lethargica (formal medical term).
• Epidemic encephalitis (descriptive term).

Notes on Meaning

• This term has a single, specific historical-medical meaning. It does not describe general tiredness or a minor illness. Its use is highly specialized.

Noun

1. an encephalitis that was epidemic between 1915 and 1926; symptoms include paralysis of the extrinsic eye muscle and extreme muscular weakness