Updated: 12/18/2020

Neisseria meningitidis

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Snapshot
  • An 18-year-old man presents to the emergency department for an intractable headache and generalized malaise. His symptoms began 3 days ago and have progressively worsened. Physical examination is significant for nuchal rigidity, diffuse petechia, and an inability to extend at the knee while the hips are flexed at 90°. A lumbar puncture is performed and cerebral spinal fluid studies demonstrate an elevated opening pressure, elevated protein, decreased glucose, and a leukocytosis. Gram stain of the cerebral spinal fluid demonstrates gram-negative diplococci.
Introduction
  • Classification
    • a gram-negative diplococcus
  • Epidemiology
    • risk factors 
      • college students
      • military
      • infants and the elderly
      • no meningococcus vaccine
  • Transmission
    • respiratory and oral secretions
  • Microbiology
    • properties
      • metabolizes glucose
      • produces IgA proteases
      • contains lipooligosaccharides (has strong endotoxin activity)
      • aerobic or facultatively anaerobic
      • maltose fermenter 
    • reservoir
      • nasopharynx
        • penetrates mucosal epithelium and enters circulation
          • pharynx → hematogenous spread (blood) → choroid plexus → meninges 
    • molecular biology
      • virulence factors
        • polysaccharide capsule 
          • an important virulence factor
            • provides resistance against phagocytosis
        • IgA protease
          • allows oropharynx colonization
        • endotoxin (lipooligosaccharide)
          • analogous to LPS from other gram-negative bacteria
          • causes hemorrhage and sepsis
          • responsible for petechial rash
            • small red dots of hemorrhage
        • pili
          • enables attachment to the nasopharynx 
          • antigenic variation avoids the immune system attack
  • Pathogenesis
    • begins as asymptomatic colonization in the nasopharynx in healthy patients
      • in rare cases, the bacteria invade through the mucosa, resulting in bacteremia, which can allow seeding of the microbe to the meninges
      • an inflammatory response against the microbe (due to its endotoxin) ensues, leading to tissue injury
        • procoagulant pathways can also be activated, causing intravascular thrombosis (e.g., purpura and petechiae)
    • Patients deficient in components of the alternative and terminal complement (C5b-C9 - membrane attack complex) pathways have increased susceptibility to recurrent Neisseria bacteremia
  • Prevention
    • meningococcal vaccine
      • indication
        • all patients 11-18 years of age
        • ≤ 10 years of age and ≥ 19 years of age who are high risk for invasive meningococcal disease
  • Associated conditions
    • meningitis
    • meningococcemia
    • purpural fulminans
    • Waterhouse-Friderichsen syndrome  
      • adrenal infarction leading to adrenal insufficiency 
  • Prognosis
    • poor prognosis include shock, young and old age, coma, purpura fulminans, and disseminated intravascular coagulation
Presentation
  • Symptoms
    • headache
    • fever
    • neck stiffness
    • nausea and vomiting
    • myalgias
  • Physical
    • petechial rash 
    • nuchal rigidity
    • Brudzinki sign
      • spontaneous flexion of the hips during passive neck flexion
    • Kernig sign
      • inability to extend the knees while the hips are flexed at 90°
Studies
  • Culture
    • perform a Gram stain of the cerebral spinal fluid or blood
      • gold standard for the diagnosis
Differential
  • Meningitis caused by other organisms
    • Streptococcus pneumoniae
    • Listeria monocytogenes
    • differentiating factors
      • different organisms are isolated with microbiologic testing
Treatment
  • Medical
    • empiric antibiotic therapy
      • indication
        • preferably given after cerebral spinal fluid cultures and blood cultures are obtained
          • given antibiotics first will impair diagnostic testing
      • regimen
        • third-generation cephalosporin
          • e.g., ceftriaxone or cefotaxime 
    • antimicrobial chemoprophylaxis
      • indication
        • ideally given within 24 hours
          • household members
          • roommates or intimate contacts
          • direct exposure to oral or respiratory secretions (e.g., kissing and endotracheal intubation)
          • sitting next to the infectious person for ≥ 8 hours
          • patients who work in a childcare center
      • medication
        • rifampin
        • ciprofloxacin
        • ceftriaxone
Complications
  • Sepsis
  • Hypovolemic shock
  • Cerebral edema and hydrocephalus
  • Cognitive impairment
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Questions (8)
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(M1.MC.17.4798) A 22-year-old female is brought to the emergency department by her roommate with a one day history of fever and malaise. She did not feel well after class the previous night and has been in her room since then. She has not been eating or drinking due to severe nausea. Her roommate checked on her one hour ago and was alarmed to find a fever of 102°F (38.9°C). On physical exam temperature is 103°F (40°C), blood pressure is 110/66 mmHg, pulse is 110/min, respirations are 23/min, and pulse oximetry is 98% on room air. She refuses to move her neck and has a rash on her trunk. You perform a lumbar puncture and the CSF analysis is shown below.

Appearance: Cloudy
Opening pressure: 180 mm H2O
WBC count: 150 cells/µL (93% PMN)
Glucose level: < 40 mg/dL
Protein level: 50 mg/dL
Gram stain: gram-negative diplococci

Based on this patient's clinical presentation, which of the following should most likely be administered?
Tested Concept

QID: 109200
1

Ceftriaxone

88%

(121/138)

2

Rifampin

2%

(3/138)

3

Erythromycin

6%

(8/138)

4

Acyclovir

1%

(2/138)

5

Dexamethasone

1%

(2/138)

M 3 C

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(M1.MC.15.75) A 19-year-old college student is brought to the emergency department by her roommate. Her roommate reports that the patient was complaining of a headache this morning. A few hours later, the patient seemed lethargic and confused. In the emergency department, the patient's vital signs are as follows: HR 98, BP 110/70, T 38.7 degrees Celsius. Her neurological exam is notable for flexion at the hips when her neck is passively flexed. A lumbar puncture is performed, and Gram stain results are shown in Figure A. Which of the following bacterial structures does the involved organism use to adhere to the nasopharynx? Tested Concept

QID: 106716
FIGURES:
1

Lipooligosaccharide

9%

(6/65)

2

Pilus

51%

(33/65)

3

Capsule

25%

(16/65)

4

Spore

3%

(2/65)

5

Glycocalyx

9%

(6/65)

M 1 B

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(M1.MC.14.1) An 18-year-old male in his first year of college presents to the emergency room with a fever and a severe headache. He reports having unprotected sex with several partners over the past few weeks. Upon examination, the male demonstrates nuchal rigidity and photophobia. His past medical history is notable for a lack of vaccinations beginning from infancy due to his parents' belief that vaccinations may cause autism. The bacteria causing these symptoms would most likely demonstrate which of the following? Tested Concept

QID: 106341
1

Positive quellung reaction

52%

(25/48)

2

Negative quellung reaction

4%

(2/48)

3

Lactose fermentation

6%

(3/48)

4

Urease positive

6%

(3/48)

5

Negative catalase test

21%

(10/48)

M 1 B

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(M1.MC.13.21) A 15-year-old female is brought to the emergency room with high fever and confusion. She complains of chills and myalgias, and physical examination reveals a petechial rash. Petechial biopsy reveals a Gram-negative diplococcus. The patient is at greatest risk for which of the following? Tested Concept

QID: 101480
1

Bilateral adrenal destruction

67%

(44/66)

2

Pelvic inflammatory disease

9%

(6/66)

3

Septic arthritis

12%

(8/66)

4

Osteomyelitis

3%

(2/66)

5

Acute endocarditis

6%

(4/66)

M 2 D

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(M1.MC.13.173) A 19-year-old man is admitted to the medical intensive care unit with suspected sepsis. Blood cultures grow Gram-negative cocci containing lipooligosaccharide in their cell wall. Which of the following would you expect to find on a detailed history and physical examination of this patient? Tested Concept

QID: 101632
1

History of consuming undercooked beef

11%

(7/62)

2

Petechial rash

71%

(44/62)

3

Ascending paralysis

8%

(5/62)

4

History of exposure to rabbit hides

5%

(3/62)

5

Rice water stools

2%

(1/62)

M 1 D

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