Meningitis Review 2024

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Questions and Answers

What is the primary vector responsible for the transmission of T.brucei species?

Housefly

Tsetse fly (correct)

Kissing bug

Mosquito

Which of the following best describes the chronic phase of Trypanosoma cruzi infection?

Death within 10 days

Cardiomyopathy and giant esophagus (correct)

Severe headache and seizures

Inflammation at the site of bug bite

What is the most likely diagnosis for a patient presenting with severe headache, vomiting, and seizure following exposure to contaminated water?

Sleeping sickness

Primary amebic meningoencephalitis (correct)

Acute bacterial meningitis

Chagas disease

What is the transmission method for Acanthamoeba infections?

Swimming or inhalation in contaminated water Signup and view all the answers

Which of the following treatments is specifically used for Trypanosoma cruzi infections?

Nifurtimox Signup and view all the answers

Which virulence factor is primarily responsible for the development of neonatal meningitis caused by E. coli?

K antigen Signup and view all the answers

What is the most effective treatment for E. coli meningitis?

Cephalosporins Signup and view all the answers

How is Listeria monocytogenes primarily transmitted?

Ingestion or at birth Signup and view all the answers

Which component of Clostridium tetani's virulence factors causes rigid paralysis?

Tetanospasmin Signup and view all the answers

What is a common symptom of tetanus?

Rigid paralysis Signup and view all the answers

Which of the following factors does NOT contribute to Listeria's virulence?

Tetanospasmin Signup and view all the answers

What is the recommended prevention method for tetanus?

Tetanus vaccine Signup and view all the answers

What type of immune response develops against Listeria monocytogenes?

Cell-mediated immunity Signup and view all the answers

What is the primary mode of transmission for the Zika Virus?

Mosquito bites Signup and view all the answers

Which symptom is NOT typically associated with St. Louis encephalitis?

Microcephaly Signup and view all the answers

What is a distinguishing feature of pneumococcal meningitis?

Prolonged fever before onset of classic triad Signup and view all the answers

What percentage of cases of West Nile virus may progress to severe symptoms involving the CNS?

1% Signup and view all the answers

Which vaccine is recommended for the prevention of Neisseria meningitidis?

MCV4 (ACWY Vaccine) Signup and view all the answers

Which treatment is recommended for Zika Virus infection?

Palliative care Signup and view all the answers

Which symptom is characteristic of bacterial meningitis in adults?

Nausea Signup and view all the answers

What type of virus is associated with LaCrosse virus?

Single negative stranded RNA virus Signup and view all the answers

What is a key characteristic of Bunyaviruses?

Single negative stranded RNA Signup and view all the answers

What treatment is commonly used for adults with bacterial meningitis?

IV Vancomycin + Ceftriaxone or Cefotaxime Signup and view all the answers

What virulence factor is specifically associated with Listeria monocytogenes?

Internalin Signup and view all the answers

Which of the following is a secondary symptom of disseminated CNS disease caused by the Cryptococcus neoformans?

Cutaneous manifestations Signup and view all the answers

What is a common treatment strategy for preventing Strep agalactiae infection?

Screening at 35-37 weeks of gestation Signup and view all the answers

Which diagnostic method is used for the Zika Virus?

RT-PCR or IgM antibody tests Signup and view all the answers

Which symptom is NOT typically observed in infants with meningitis?

Classic signs like headaches Signup and view all the answers

What is the primary target group for the Hib polyribose phosphate vaccine?

Children aged 1 month to 3 years Signup and view all the answers

Which symptom is linked to meningococcal meningitis specifically?

Petechial rashes Signup and view all the answers

What type of infection is Strep pneumoniae known to cause?

CNS meningitis Signup and view all the answers

What is the main virulence factor of Clostridium botulinum responsible for causing flaccid paralysis?

Botulinum toxin that blocks ACh release Signup and view all the answers

What symptom is commonly associated with botulism in infants, known as 'Floppy Baby Syndrome'?

Flaccid paralysis Signup and view all the answers

How is leprosy primarily transmitted?

Direct contact with an infected individual Signup and view all the answers

What is a characteristic finding in tuberculoid leprosy?

Granuloma formation with little bacilli Signup and view all the answers

Which form of leprosy is characterized by a poor cell-mediated immune response and many bacteria?

Lepromatous leprosy Signup and view all the answers

What potential risk is associated with the antitoxin treatment for botulism?

Serum sickness Signup and view all the answers

Which statement regarding botulism spores is true?

They are present in anaerobic environments and soil. Signup and view all the answers

What is the method of infection for botulism in infants?

Ingestion of the botulinum toxin Signup and view all the answers

What laboratory method is typically used for diagnosing leprosy?

Acid-fast stain of skin Signup and view all the answers

Which best describes the role of the mycolic acid in Mycobacterium leprae?

Enhances pathogenicity and assists in immune evasion Signup and view all the answers

What is the primary method of rabies transmission in the US?

Wild animal bites Signup and view all the answers

Which of the following is NOT a symptom of encephalitic rabies?

Flaccid paralysis Signup and view all the answers

What type of virus is rabies classified as?

Negative single-stranded RNA virus Signup and view all the answers

How does rabies enter the central nervous system (CNS)?

Via axon transport to the neuron cell body Signup and view all the answers

Which method is used for rabies diagnosis when infection is suspected?

Skin biopsy for viral antigens Signup and view all the answers

What is the incubation period for rabies?

Weeks to years Signup and view all the answers

What prevents effective treatment for rabies once symptoms appear?

The failure to detect the virus in blood Signup and view all the answers

What is a characteristic of poliovirus?

Non-segmented positive single-stranded RNA virus Signup and view all the answers

Which of the following tests can be used for diagnosis of poliovirus infection?

Immunization history check Signup and view all the answers

What type of vectors mainly transmit arboviruses?

Mosquitoes and ticks Signup and view all the answers

How are flaviviruses spread?

Via a bridge vector Signup and view all the answers

What is a potential outcome of infection with any strain of rabies?

Fatality in most cases Signup and view all the answers

What complication arises during the replication of rabies that aids in its survival?

Decreased immune signaling Signup and view all the answers

Which clinical manifestation occurs in paralytic rabies?

Severe muscle weakness Signup and view all the answers

Study Notes

Meningitis Review - 1/22/2024

This review covers bacterial, fungal/TB, and viral meningitis, along with tetanus and botulism.

CSF Findings in Meningitis

Bacterial: Increased opening pressure, increased PMNs, increased protein, decreased sugar
Fungal/TB: Increased opening pressure, increased lymphocytes, increased protein, decreased sugar
Viral: Normal/slightly increased opening pressure, increased lymphocytes, normal/slightly increased protein, normal sugar

Bacterial Meningitis, Tetanus, and Botulism

Bacterial Meningitis:
- Children (<3 months) and adult meningitis, neonatal meningitis
- Key causes: Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae Type B, Listeria monocytogenes (immunocompromised)
- Strep agalactiae, E. coli, and Listeria monocytogenes are also causes in neonatal meningitis
Tetanus:
- Clostridium tetani
Botulism:
- Clostridium botulinum

Bacterial Meningitis Overview

Newborns/Children Symptoms:
- Constant crying, poor feeding, sleeping constantly, irritability
Adult Symptoms:
- Classic triad: fever, headache, stiff neck.
- Sensitivity to light, confusion, nausea, vomiting
- General flu-like symptoms (developing 1-2 days after initial symptoms) may also be present; Petechial rashes
Diagnosis:
- Physical exam (Kernig's sign, Brudzinski's sign)
- CSF analysis (increased polymorphonuclear neutrophils [PMNs], increased protein, decreased glucose)
Treatment:
- Empirical treatment—IV vancomycin + ceftriaxone or cefotaxime

Strep pneumoniae

Leading cause of CNS meningitis
"Pneumococcal meningitis" = caused by Strep pneumo
Distinguishing feature: prolonged fever before onset of classic triad (apparent focal infection)
Virulence factors: polysaccharide capsule, IgA protease, autolysin, pneumolysin

Neisseria meningitidis

"Meningococcal meningitis"
Bacteremia can cause septicemia
Focal infection is often inapparent
Distinguishing feature: petechial rashes
Virulence factors—polysaccharide capsule, pili (adherence in nasopharynx), lipooligosaccharide, IgA protease, OpA, OpC.
Treatment: ceftriaxone or penicillin G

Haemophilus influenzae type b

"Typeable" = has a capsule
Apparent focal infection
Primarily in non-immunized children (1 month to 3 years)
Prevention: Hib polyribose phosphate vaccine

Strep agalactiae

Usually transmitted during birth (both baby and mother can get meningitis)
Virulence factors—Polysaccharide capsule rich in sialic acid, Hemolysin, C5a peptidase

E. coli

Ferments lactose on MacConkey agar
Virulent factors: K antigen (main virulence factor for development of neonatal meningitis), O antigen, H antigen
Meningitis caused by E. coli is transmitted at birth, often with no apparent disease preceding it
Treatment: Cephalosporins

Listeria monocytogenes

Foodborne infection (can grow at 4°C)
Transmission via cell-to-cell transfer or at birth.
Virulence factors: Internalin, Listeriolysin O, ActA
Can affect pregnant women and fetus (infection in utero)
Prevention:
- Treatment of infants with ampicillin.

Tetanus Overview

Symptoms:
- Rigid paralysis: lockjaw (trismus), back spasm, potential respiratory failure due to paralysis of chest muscles
Treatment:
- Supportive (ventilation, muscle relaxants) +
- Human tetanus immune globulin (HTIG) +
- Antibiotics (metronidazole)

Clostridium tetani

Virulence factor: tetanospasmin
Blocks release of inhibitory neurotransmitters (increasing firing rate of motor neurons) causing rigid paralysis.
Transmission: C. tetani spores inoculated into puncture wounds (e.g. rusty nails)
Prevention: tetanus vaccine

Botulism Overview

Symptoms:
- Flaccid paralysis ("Floppy Baby Syndrome")
- GI symptoms (foodborne intoxication)
- Symptoms onset quicker than tetanus
Treatment:
- Supportive (ventilation)
- Antitoxin (equine trivalent) +
- Antimicrobials (if wound infection is involved)

Clostridium botulinum

Virulence Factors: Botulinum toxin blocks release of ACH, resulting in no muscle contraction and flaccid paralysis
Transmission: spores found in soil, surfaces of fruits, and vegetables; Home canning of such as honey
Prevention or treatment: No current vaccine; no natural immunity

Leprosy - Mycobacterium Leprae

Obligate aerobe; non-motile, non-spore forming; Acid fast bacillus (Ziehl-Neelsen stain); Lipid cell wall, mycolic acid
Transmission: via prolonged contact
Virulence factors: PGL-1 (invasion into Schwann cells); Laminin-binding protein (binding to basal lamina of peripheral nerves)
Different forms: Tuberculoid and Lepromatous

Leprosy - Lepromatous and Tuberculoid

Tuberculoid:
- Cell-mediated response (Th1 and CD8+ T cells)
- Granuloma formation (little bacilli)
- Lepromin skin test positive
- Large, asymmetric, pale, hairless, flattened macules on face, trunks, limbs
Lepromatous:
- Poor cell-mediated response
- Multiple symmetric nodules and plaques—diffuse spread
- Can cause bone resorption and folding of skin
- Negative Lepromin skin test

Viral CNS Infections

Important to note different routes, symptoms and causes of infections.

Important Definitions

Direct contact: Includes petting, touching, bites, and scratches.
Indirect contact: Includes places animals live, like chicken coops or aquarium tanks. Plants, soil, etc.
Vector-borne: Transmittal by ticks, mosquitoes, or fleas.
Food-borne: Ingesting contaminated animal products (meat, milk, eggs) and plants.
Sylvatic: Between wild animals involving insect intermediates.
Urban: When an infection moves from sylvatic cycle to humans—usually via insect, direct contact, or domestic animals.

Rabies

Negative single-stranded RNA
Enveloped (glycoprotein surface spikes, phosphoprotein spikes)
Zoonotic with a sylvatic and urban cycle
Replication at slow rates to avoid apoptosis
Fatal

Rabies (Cont.)

Pathogenesis: Incuation varies. Once in brain, replicates and damages axons, spreads anterograde.
Clinical illness: Encephalic (furious) or paralytic (20%). Symptoms are severe and consistent that includes confusion, difficulty swallowing, coma/seizures, death.
Diagnosis: History of exposure, symptoms, post-mortem (Negri bodies in brain tissue).
Treatment: No effective treatment once symptoms emerge.

Poliovirus

Positive single-stranded RNA
Non-enveloped enterovirus
Transmitted via oral/fecal route
Most people asymptomatic; some get poliomyelitis; 1% develop major illnesses
Diagnosis—immunization history, CSF, throat, and stool cultures;
Prevention: oral vaccine (live, attenuated, some reversion); inactivated vaccine for those immunocompromised

Arboviruses

Seasonal fluctuations (mosquitoes & ticks)
Enveloped, positive single-stranded RNA virus
Transmitted to humans by "bridge" vector (replication starts in cytoplasm-> lytic, destroys cells -> viremia across the CNS (blood); inflammation allows for permeability in brain so viruses can enter).
Symptoms: may include abrupt fever, chills, weakness, headache, myalgia; diffuse CNS; fever, headache, irritability, nausea, seizures, coma, and death.

Flaviviruses

Positive enveloped single-stranded RNA
Incubation period ~1 week
Spread via "bridge" vectors
Shares common antigen with EEEV.
Flaviviruses in US: St. Louis encephalitis, West Nile, Zika virus

St. Louis Encephalitis and West Nile

St. Louis Encephalitis:
- Viral saturation of reticuloendothelial system
- Invasion of CNS causing sudden onset of symptoms (fever, malaise, headache, dizziness, nausea).
- Symptoms worsen with disorientation, confusion, irritability, tremors, convulsions
- Death via palliative care in more severe cases.
West Nile:
- Transmission by mosquito bites.
- Migrates to lymph nodes—Blood stream→organs (often the spinal cord).
- Usually self-limited with mild symptoms (fever, malaise, nausea).
- More severe forms can involve CNS (severe muscle weakness, flaccid paralysis; stupor/ seizures / coma).

Zika Virus

Usually mild, self-limiting flu-like disease
Spread by mosquito bite
Concerning in pregnant women; causes vertical transmission from mother
Neuroinvasive (Guillain-Barre and microcephaly)
Transmission (initial sporadic, increasing urban/suburban spread → vertical transmission across placenta → sexual transmission)
Diagnosis (RT-PCR and/or IgM antibody)
Treatment: (none - palliative care) Prevention (Mosquito control and restrict pregnant women travel)

Bunyaviruses

Single-stranded segmented negative sense RNA virus (LaCrosse virus–California encephalitis)
Secondary viremia in CNS (symptoms more likely in people <16 years old)
Neurological sequelae (20% of survivors (often permanent))
Diagnosis: serum antibody or RT-PCR tests
Treatment: (none - palliative care) Prevention (Mosquito control)

Polyomaviruses

Non-enveloped double-stranded DNA
Common infection in childhood, remains dormant in some people
Activated when immune systems are weakened. (common in HIV people)
Causes Progressive Multifocal Leukoencephalopathy
Includes a range of symptoms like impaired speech, mental issues, paralysis / sensory abnormalities / death
No prevention

Prions

Transmissible spongiform encephalopathies (prion diseases).
Not infectious particles, but rather proteins
Infectious protein particles form insoluble aggregates
Proposed mechanism: holes in tissues (sponge-like) during multiplication (H and E)
Most common: Creutzfeldt-Jakob disease (CJD).

Creutzfeldt-Jakob

Rapidly progressive neurologic dysfunction
Myoclonic jerks, visual abnormalities, akinetic mutism
GSS disease or FFI includes a range of symptoms (ataxia, amyloid deposition, neurofibrillary tangles, insomnia etc).
Death typically occurs within a year.
High mortality rate (100%)
No effective treatment

Fungal Meningitis

Characteristics:
- Low glucose
- High protein
- Increased opening pressure
- Increased lymphocytes

Cryptococcus Neoformans

Asymptomatic in healthy people; opportunistic in HIV patients
Flu-like symptoms, headaches, fever, disseminated disease (lungs, skin, bones)
Virulence Factors: Polysaccharide capsule (prevents phagocytosis), phenoloxidase (increased melanin + prevents binding of phagosome to lysosome)
Characteristics: India Ink and Halo stain, Brain abscesses
Treatment: Amphotericin + Flucytosine, then Fluconazole, prophylactic <100 CD4

Coccidioides Immitis

Dimorphic fungi
Asymptomatic/flu-like symptoms – can disseminate to many body locations (lungs, skin, bones, CNS).
Transmission: Southwestern USA, spores inhalation
Characteristics: Spherules of endospores
Treatment: usually self-limited; fluconazole; amphotericin B (disseminated)

Protozoal Meningitis

General term for protozoal infections that involve the meninges (protective membranes of the brain and spinal cord)

African Trypanosomiasis (Sleeping sickness)

T. brucei gambiense: (Western Africa, chronic, human reservoir - infection can last 1 year to death).
T. brucei rhodesiense: (Eastern Africa, acute, wild animals - infection lasts between 3-6 weeks):
Transmission: Tsetse fly
Stages: Chancre; Trypomastigotes in blood (recurrent malaise, lymphadenopathy w/ IgM production. Varying antigens, surface glycoprotein.) Meningitis - headaches; behavior change.

American Trypanosomiasis (Chagas disease)

Trypanosoma cruzi: Southern US and Argentina
Transmission: Contact with reduviid (Kissing bug) feces (bite—skin, defecate, enters skin)
Virulence: Penetrin (invasion of cells), Pore-forming protein, Multiply intracellularly and rupture cell.
Presentation: Acute chagoma, Romña's sign(eye), heart, brain, liver, spleen. Chronic: cardiomyopathy/arrhythmias, giant esophagus.
Diagnosis: Motile trypanosomes in body fluid.
Treatment: Nifurtimox, benznidazole

Naegleria Fowleri

Amoeba
Free-living in lakes and swimming pools
Transmission: Penetration of olfactory neuroepithelium (through nose)
Presentation: Primary amebic meningoencephalitis: severe headache, vomiting, seizure, coma
Death: within 10 days
Diagnosis: Trophozoites in cerebrospinal fluid (CSF)

Acanthamoeba

Primarily affects immunocompromised individuals
Transmission: Brackish and saltwater; acquired via swimming or inhalation
Spread: blood → CNS + lungs + sinuses + skin
Presentation: subacute or chronic: headache, altered mental status; skin lesions; corneal ulcerations
Diagnosis: Trophozoites in CSF or brain biopsy/skin scraping (monocytes in CSF)
Treatment: Self-limiting.

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Description

This quiz comprehensively reviews different types of meningitis, including bacterial, fungal/TB, and viral, as well as related conditions like tetanus and botulism. It highlights key CSF findings associated with each type, demographics, and common pathogens linked to bacterial meningitis in various age groups. Test your understanding and retention of critical concepts regarding these infectious diseases.