Lumbar Puncture and CSF Analysis Quiz

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Questions and Answers

What symptoms suggest meningeal irritation in a patient?

Nausea and vomiting

Fever and tachycardia

Increased white cell count

Headache and photophobia (correct)

What is the primary reason for performing a lumbar puncture in suspected bacterial meningitis?

To drain cerebrospinal fluid

To confirm the presence of a virus

To relieve pressure on the brain

To analyze and obtain CSF for diagnosis (correct)

What is the most common contraindication to performing a lumbar puncture?

Patient's age over 60

Hypertension

Local infection at the puncture site (correct)

Previous lumbar surgery

Which finding is characteristic of bacterial meningitis in CSF analysis?

Elevated protein levels Signup and view all the answers

What precautions should be taken to prevent infection during a lumbar puncture?

Wearing sterile gloves and mask Signup and view all the answers

What symptom seen in the clinical case suggests a systemic bacterial infection?

Fever of 39ºC Signup and view all the answers

Which preliminary test is most critical for diagnosing meningitis after a lumbar puncture?

CSF culture Signup and view all the answers

What clinical sign is indicative of meningeal irritation?

Kernig's sign Signup and view all the answers

What type of pathogens can PCR be used to identify in CSF samples?

Both bacterial and viral pathogens Signup and view all the answers

What is the normal appearance of CSF in a healthy adult?

Clear and colorless Signup and view all the answers

Which of the following should be included in the laboratory examination of CSF?

Cell count and differential Signup and view all the answers

For a patient with suspected bacterial meningitis, how would you expect the CSF glucose level to compare to the serum glucose level?

CSF glucose will be less than 60% of serum glucose Signup and view all the answers

What is the typical cellular profile of CSF in a patient with bacterial meningitis?

High cell count with predominance of polymorphs Signup and view all the answers

When transporting CSF samples to the laboratory, what is the most appropriate method?

Seal in leak-proof bags and hand deliver ASAP Signup and view all the answers

Based on the example CSF results, what is the most likely type of meningitis in this case?

Bacterial meningitis Signup and view all the answers

What is the typical protein level in CSF for normal adults?

Between 15-45 mg/dl Signup and view all the answers

What is the typical cell count in CSF for an adult without any pathology?

0 - 5 cells/mm3 Signup and view all the answers

Which finding in CSF is an indicator of bacterial meningitis?

Cell count of 540 white cells/mm3 Signup and view all the answers

What is the normal glucose to serum glucose ratio for CSF?

0.6 Signup and view all the answers

Which of the following additional tests is used for identifying specific pathogens in CSF?

PCR for bacteria/virus/fungi Signup and view all the answers

What is the characteristic protein level in CSF during bacterial meningitis?

80 mg/dl Signup and view all the answers

In the transport of CSF, which method is improper?

Sending via the chute system Signup and view all the answers

What can a student infer from a CSF glucose level of 0.3 mmol/l when serum is 5.7 mmol/l?

Bacterial meningitis likely Signup and view all the answers

What is a common characteristic of the CSF appearance in a case of purulent meningitis?

Cloudy Signup and view all the answers

What patient factors would most clearly indicate the need to perform a lumbar puncture?

Signs of meningeal irritation Signup and view all the answers

In a patient with suspected bacterial meningitis, what clinical sign would you identify as most significant in the diagnosis?

Positive Brudzinski's sign Signup and view all the answers

Which combination of CSF analysis findings would most strongly suggest a bacterial meningitis diagnosis?

Low glucose, elevated protein, and high neutrophil count Signup and view all the answers

What is the most important aspect of patient safety during a lumbar puncture?

Ensuring aseptic technique to prevent infection Signup and view all the answers

What should be prioritized when preparing to perform a lumbar puncture on a patient with neck stiffness and fever?

Checking for the presence of contraindications Signup and view all the answers

During the interpretation of a CSF analysis for suspected bacterial meningitis, which factor would most likely be misinterpreted by students?

Clear appearance of CSF Signup and view all the answers

Which microbial feature would be most critical in determining the course of treatment for a patient diagnosed with bacterial meningitis?

Presence of Gram-positive cocci Signup and view all the answers

What is a common misconception regarding the CSF analysis in patients with bacterial meningitis?

Lymphocytes are predominantly elevated in bacterial infections Signup and view all the answers

Study Notes

Lumbar Puncture, CSF Analysis and Interpretation

Learning Outcomes:
- Recognize when lumbar puncture (LP) is necessary, including contraindications and risks to health.
- Employ appropriate precautions to protect the patient and oneself during LP.
- Describe the diagnostic pathway for processing CSF specimens from patients with CNS infections.
- Interpret biochemical, cellular, and preliminary microbiological results of CSF analysis.

Clinical Case 1

Patient: 63-year-old female with new-onset headache, photophobia, neck stiffness, and fever.
Examination: Fever of 39°C, heart rate of 120/min, positive Kernig's sign, no localizing neurological signs or rash.
Investigations: White blood cell count of 16 x 10^9/L (normal range 4-11).

Differential Diagnosis

Likely Diagnosis: Bacterial meningitis, due to the patient's systemic illness (fever, tachycardia) and elevated white blood cell count.

Investigations for Bacterial Meningitis

CSF Analysis: Gram stain, cell count, protein and glucose, culture, PCR (bacterial: N. meningitidis, Streptococcus pneumoniae, Listeria monocytogenes; viral).
Blood Culture: Assess for bacteremia.
Blood PCR: Additional testing when available.

CSF Transportation

Transport CSF samples in leak-proof bags to the laboratory as soon as possible.
Do not send via the chute system.

CSF Laboratory Analysis

Appearance: Clear, cloudy, purulent, bloody.
Microscopy: Cell count and differential (morphology of cells), Gram stain.
Biochemistry: Protein, glucose, spectrophotometry.
Culture and Susceptibility: Identifying pathogens and their responses to antibiotics.
Additional Tests: PCR (bacterial, virus, fungi), antigen/antibody tests (e.g., cryptococcal, neuroborreliosis), cytology, biomarkers.

Normal CSF Findings in Adults

Appearance: Clear and colorless.
Cellular: Normally acellular; however, <5 white cells and <5 red cells are acceptable if obtained by LP.
Protein: 15-45 mg/dL.
CSF:Serum Glucose Ratio: > 0.6.

Raised Protein/Low Glucose CSF - Possible Causes

Multiple sclerosis
Bacterial meningitis
Tuberculosis meningitis
Subarachnoid hemorrhage
CNS fungal infections

Management of Meningitis

ABCs: Airway, Breathing, Circulation; IV fluids, possibly ventilation.
Antibiotics: Administered promptly, ideally before/with other antibiotics.
Steroids: Administered before or with antibiotics
ICU Support: Especially for organ support related to bacteremia or sepsis.
Seizure Management: If necessary.
Correction of Coagulation Abnormalities: As needed.

Case 1: Empirical Therapy (Adults)

3rd-generation Cephalosporin (Cefotaxime/ceftriaxone): Because it crosses the blood-brain barrier.
Vancomycin: For possible penicillin-resistant pneumococci.
Amoxicillin: Addition, if Listeria suspected, patient is elderly, immunocompromised, or pregnant.
Steroids: Prior to the first dose of antibiotics.

Case 1: CSF Results (Day 1)

Cell count: 540 white blood cells/mm³ (abnormal).
CSF protein: 80 mg/dL (abnormal).
CSF glucose: 0.3 mmol/L (low).
Blood glucose: 5.7 mmol/L.

Likely Pathogen

Bacterial: Given the high white blood cell count, low CSF glucose, and presence of bacteria on the Gram stain.

Typical Bacterial Pathogens

Neonates: Group B Streptococcus, E. coli, Listeria monocytogenes.
Children/Adolescents: Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae.
Older Adults/Immunocompromised, Pregnant: Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes, Staphylococcus aureus.

Case 1: CSF Gram Stain (Day 1)

Gram-positive diplococci.

Case 1 Culture Results (Day 2)

Streptococcus pneumoniae detected .

Case 1: Day 3 Therapy Changes

Stop vancomycin and amoxicillin.
Consider if oral antibiotics can be started if the patient is stable.
Minimum 14 days of intravenous antibiotics for uncomplicated pneumococcal meningitis.

Potential Complications of Lumbar Puncture

Back pain
Bleeding
Cerebral herniation
Infection
Post-LP headache

Clinical Case 2

Patient: 53-year-old male with headache, neck stiffness, fever, and reported episode of shaking/unresponsiveness.
Examination: Fever of 39.5°C, HR 130/min, BP 90/60 mm Hg, positive Kernig's sign.
Investigations: White blood cell count 20 x 10^9/l, CRP 150 mg/L.

Contraindications to Lumbar Puncture

Relative: Platelet count 20-40 x 10^9/L, thienopyridine therapy.
Absolute: Non-communicating obstructive hydrocephalus, uncorrected bleeding diathesis, anticoagulant therapy, platelet count <20 x 10^9/L, spinal stenosis or spinal cord compression above the puncture level, local skin infections, spinal or cranial developmental abnormalities.

Clinical Case 3

Patient: 45-year-old female with acute onset confusion, increasing drowsiness, and pyrexia. Headache for the previous 2 days.
Examination: Temperature 38°C, BP 100/70, HR 90, not oriented. No rashes or other skin lesions. No sick contacts or recent travel history.

Case 3: Likely Pathogens (HPSC data 2019)

Potential pathogens include varicella/herpes zoster virus, enteroviruses, herpes simplex virus, parechovirus, human herpes virus type 6, and tick-borne encephalitis virus.

Case 3: Microbiological Investigations

CSF for Gram stain, cell count, protein & glucose, culture, PCR (viral & bacterial).
Blood culture.

Case 3: Radiological Investigations

MRI brain is a useful tool in diagnosis.

Case 3: HSV Encephalitis MRI Findings

Asymmetrical changes in the medial temporal lobes.

Case 3 CSF Results

CSF Appearance: cloudy
Erythrocyte count: 3 cells/mm³
Leucocyte count: 60 cells/mm³
Polymorphs: 2%
Lymphocytes: 98%
Other cells: 0%
CSF Total Protein: 60 mg /dL
CSF glucose: 65 mg/dL
Blood glucose: 75 mg/dL
Gram stain: negative

Case 3 Empirical Therapy

Acyclovir 10 mg/kg t.d.s. IV

Case 3: HSV-DNA detected by PCR

Continue acyclovir.
Anti-infective therapy for 21 days, administer intravenously.
No antibiotic prophylaxis for contacts.
Notify public health.

Clinical Case 4

Patient: 36-year-old male with acute onset headache, photophobia, and pyrexia, receiving chemotherapy for lymphoma.
Examination: Temperature 38°C, BP 90/70, HR 100, positive Kernig's sign. No other significant findings.
Investigations: WBC 6 x 10^9/L, platelets 3 x 10^9/L, CRP 250 mg/L.

Clinical Case 5

Patient: 38-year-old female with chronic headache, low-grade pyrexia, weight loss, and increasing confusion with a history originally from India.
Examination: Temperature 37.8°C, BP 110/80, HR 90, positive Kernig's sign. No other significant findings.
Investigations: WBC 12 x 10^9/L, CRP 60 mg/L (normal ranges).

Case 5 CSF Results

CSF Appearance: cloudy
Erythrocyte count: 5 cells/mm³
Leucocyte count: 2000 cells/mm³
Polymorphs: 4%
Lymphocytes: 96%
Other cells: 0%
CSF Total Protein: 60 mg /dL
CSF glucose: 20 mg/dL
Blood glucose: 65 mg/dL

Additional tests in case 5

CSF Ziehl-Neelsen or auramine stain
CSF TB PCR
CSF TB culture
Chest X-ray (CXR)
sputum for TB culture if productive

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Description

Test your knowledge on the indications and procedures of lumbar puncture, including patient safety and CSF analysis. This quiz also covers the interpretation of results in cases of central nervous system infections, especially bacterial meningitis. Enhance your understanding of clinical diagnostics with real case scenarios.