Meningitis: Disease Overview

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Questions and Answers

What is the primary characteristic of acute pyogenic meningitis (APM)?

It primarily affects the brain's cortex.

It is an inflammation of the leptomeninges. (correct)

It causes chronic inflammation of the brain.

It is a slowly progressing infection of the spinal cord.

In which demographic is the median age of patients with APM currently reported to be?

Teens aged 13 to 19 years

Children under 5 years

Young adults aged 25 years (correct)

Adults over 60 years

What risk factor is associated with neonatal APM?

Increased incidence in premature births (correct)

A major cause being viral infections

A decreased incidence in African-American populations

Higher prevalence in females compared to males

Which race is noted to have a higher incidence rate of APM in pediatric populations?

African-American and Native American children Signup and view all the answers

Which statement accurately describes the nature of APM?

APM is often related to the patient's age. Signup and view all the answers

Which of the following describes the prevalence of APM among older adults?

It is significantly high compared to young children. Signup and view all the answers

What is the male-to-female ratio for cases of neonatal APM?

3:1 Signup and view all the answers

What type of meningitis is primarily caused by bacteria?

Acute pyogenic meningitis Signup and view all the answers

How quickly does acute pyogenic meningitis typically spread?

Extremely rapidly Signup and view all the answers

What is a common clinical symptom reported in older children with CNS-specific issues?

Lethargy Signup and view all the answers

What is the typical appearance of CSF in cases suggesting bacterial infection?

Cloudy Signup and view all the answers

What is the neutrophil count range in the CSF indicative of bacterial infections?

200–200,000/mm3 Signup and view all the answers

What is the appropriate antibiotic for treating S.pneumoniae infections?

Penicillin G Signup and view all the answers

How does the glucose concentration in CSF typically compare to serum glucose levels in bacterial infections?

50% of serum glucose Signup and view all the answers

What is a crucial characteristic of CSF findings in bacterial meningitis?

Elevated protein concentration Signup and view all the answers

Which antibiotic is preferred for H.influenzae if the strain is β-lactamase producing?

Cefotaxime Signup and view all the answers

What is the main reason glucose levels in CSF are typically at 50% of serum levels during bacterial infections?

Utilization by bacteria Signup and view all the answers

In the context of CSF culture results, what is the percentage of positivity for bacterial cultures in cases of APM?

90% Signup and view all the answers

Which antibiotic is suitable for treating Escherichia coli infections?

Ceftriaxone Signup and view all the answers

Which condition is NOT considered a risk factor for infections that spread to the meninges?

Asthma Signup and view all the answers

What role do polysaccharide capsules play in central nervous system bacterial pathogens?

They protect microbes from white blood cell phagocytosis. Signup and view all the answers

At what age is Streptococcus pneumoniae more commonly associated with meningitis infections?

30–60 years Signup and view all the answers

Which of the following infections can directly extend to the subarachnoid space?

Sinus infection Signup and view all the answers

What complication is caused by the rapid accumulation of exudate in the central nervous system?

Increased viscosity of cerebrospinal fluid Signup and view all the answers

What condition is a result of prolonged use of high-dose corticosteroids?

Immunoglobulin deficiency Signup and view all the answers

Which of the following is a classic risk factor for bacterial meningitis in individuals aged 60 and older?

Gram-negative enterics Signup and view all the answers

Which of the following correctly describes the pathophysiological spread of infections causing acute purulent meningitis (APM)?

Transport through the bloodstream from other infection sites Signup and view all the answers

What is a common risk factor related to immune defenses in meningitis infections?

Alcohol consumption Signup and view all the answers

What is a potential danger of performing a spinal tap in a patient with a brain abscess?

It may cause herniation of the brainstem. Signup and view all the answers

Which sign is indicated by a patient experiencing pain in the hamstrings upon knee extension with hips flexed at 90°?

Positive Kernig sign Signup and view all the answers

Which of the following clinical manifestations is least likely to be present in a patient with APM?

Severe abdominal pain Signup and view all the answers

What role does polymerase chain reaction testing of CSF play in diagnosing CNS infections?

Identifies bacterial infections rapidly. Signup and view all the answers

How is the microbial agent responsible for APM related to the patient?

It is closely linked to the age of the patient. Signup and view all the answers

When is a CT scan typically recommended in the context of suspected CNS infections?

Before lumbar puncture if a brain abscess is suspected. Signup and view all the answers

Which of the following symptoms in young infants may suggest APM?

Altered sleeping pattern Signup and view all the answers

What does a positive Brudzinski sign indicate?

Involuntary flexing of knees in response to neck flexion. Signup and view all the answers

What is the primary cause of neck and back stiffness seen in CNS infections?

Inflammation of the meninges. Signup and view all the answers

Study Notes

Disease Summary

Acute pyogenic meningitis (APM) is a serious inflammation of the leptomeninges, which includes the pia mater and arachnoid, affecting the cerebrospinal fluid (CSF) and ventricular system.
APM, commonly referred to as bacterial meningitis, is predominantly caused by various bacteria.
The infection spreads rapidly due to CSF circulation around the brain and spinal cord.

Prevalence

Higher incidence of meningitis in older adults compared to young children, with a median patient age of 25 years.
Neonatal APM incidence is 0.25–1 case per 1,000 live births, with 2.5 cases per 1,000 premature births.
Among neonates, the male-to-female ratio is 3:1, showing a disparity in incidence rates among pediatric African-American and Native American populations.

Causes and Risk Factors

Bacterial causes of APM vary according to patient age and include conditions that allow infections to reach the meninges.
Key risk factors include:
- Respiratory tract infections
- Otitis media (middle ear infections)
- Mastoiditis (inflammation of the mastoid process)
- Sinusitis
- Neurosurgery and head trauma
- Alcoholism and high-dose corticosteroid use
- Conditions like splenectomy, sickle cell disease, and immunoglobulin deficiency

Pathophysiology

APM typically arises from infections in other body areas, with microbes entering through the bloodstream or extending from infected sites to the subarachnoid space.
Common bacterial pathogens include:
- Haemophilus influenzae and Neisseria meningitidis in ages 1 month to 29 years
- Streptococcus pneumoniae in ages 30-60 years
- S. pneumoniae, gram-negative enterics, and Listeria monocytogenes in patients over 60
Accumulation of exudate leads to increased CSF viscosity, hindering normal flow and raising intracranial pressure.

Diagnosis

Rapid testing methods like polymerase chain reaction for bacteria and CT scans are vital for timely diagnosis.
There are significant clinical manifestations relevant to CNS infections, including:
- Headache, fever, chills, neck and back stiffness, nausea, vomiting, photophobia
- CSF abnormalities, positive Kernig sign (pain when extending knees in hip flexion), positive Brudzinski sign (flexing knees when neck is flexed)

Clinical Presentation

Common Signs:
- Infants may show irritability, altered sleep, high-pitched cry, decreased appetite.
- Older children may exhibit lethargy, somnolence, and confusion.
Analysis of CSF reveals:
- Cloudy appearance, neutrophil count of 200–200,000/mm³, glucose concentration at 50% of serum glucose level, and elevated protein concentration (≥50 mg/dL).

Treatment

Antibiotic therapy should be tailored based on the identified pathogens:
- Penicillin G is preferred for S. pneumoniae and N. meningitidis.
- Cefotaxime or ampicillin is used for H. influenzae according to strain type.
- Cefotaxime or ceftriaxone is indicated for Escherichia coli infections.

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Description

This quiz covers Acute Pyogenic Meningitis (APM), a critical inflammation of the brain and spinal cord's membranes. Explore its definition, causes, and implications of bacterial meningitis. Test your knowledge on this potentially fatal condition and its impact on cerebrospinal fluid.