16.1 CASE STUDY

A 22-year-old female schoolteacher was brought to the emergency room after a 2-day history of headache and fever. On the day of admission the patient was confused and highly agitated. Purpuric skin lesions were present on her trunk and arms. Gram stain of CSF showed many gram-negative diplococci, and the same organisms were isolated from blood and CSF. 


What is the most likely organism responsible for this fulminant disease? What is the most likely source of this organism?

  • Given the clinical presentation of rapid onset, purpuric skin lesions, and the presence of gram-negative diplococci in the CSF, the most likely organism responsible for this fulminant disease is Neisseria meningitidis. This bacterium is also known as the meningococcus and is a common cause of bacterial meningitis, particularly in young adults.


  • The most likely source of this organism is the respiratory tract. N. meningitidis is often found as a commensal in the nasopharynx of healthy carriers. The bacterium can be transmitted from person to person through respiratory droplets, such as those produced by coughing, sneezing, or close face-to-face contact. In some individuals, the bacteria can invade the bloodstream and then reach the meninges, causing meningitis. Outbreaks can sometimes occur in close-knit communities, such as military barracks, college dormitories, and boarding schools, which might explain the young teacher's exposure. Vaccination against some strains of N. meningitidis can help prevent the disease, especially in high-risk populations or areas.

Mind Map: Neisseria meningitidis and Meningococcal Meningitis

Central Idea: Neisseria meningitidis as the causative organism for fulminant disease

Main Branch 1: Clinical Presentation

  • Rapid onset of symptoms

  • Headache and fever

  • Confusion and agitation

  • Purpuric skin lesions on trunk and arms

    • purpura: a rash of purple spots on the skin caused by internal bleeding from small blood vessels

Main Branch 2: Neisseria meningitidis

  • Gram-negative diplococci

  • Also known as meningococcus

  • Common cause of bacterial meningitis

  • Particularly affects young adults

Main Branch 3: Source of Organism

  • Respiratory tract

  • Commensal in the nasopharynx of healthy carriers

  • Transmitted through respiratory droplets

  • Close face-to-face contact, coughing, sneezing

  • Outbreaks in close-knit communities

Sub-Branch 1: Transmission

  • Respiratory droplets

  • Coughing

  • Sneezing

  • Close face-to-face contact

Sub-Branch 2: Invasion and Disease

  • Bacteria invade bloodstream

  • Reach the meninges

  • Causes meningitis

  • Fulminant disease

Sub-Branch 3: High-Risk Populations

  • Military barracks

  • College dormitories

  • Boarding schools

  • Close-knit communities

Sub-Branch 4: Prevention

  • Vaccination

  • High-risk populations

  • Areas with outbreaks

Note: This mind map provides a concise overview of the central idea, main branches, and sub-branches related to Neisseria meningitidis and meningococcal meningitis. It highlights the clinical presentation, the organism itself, its source, transmission, disease progression, high-risk populations, and prevention strategies.