Lab diagnosis of Meningitis

It discusses laboratory tests involved in diagnosing meningitis with more emphasis on details of each test and findings, esp useful for microbiologists and medical students.

1. Lab diagnosis of Meningitis By Jagjit Khosla

2. Types of Meningitis Pyogenic Tubercular Aseptic Pyogenic Bacteria Eg . N. Meningitidis , S. pneumoniae , H. Influenzae Mycobacterium Tuberculosis Viral, Fungi and protozoa

3. Sample Collection Transport Initial Processing Reporting Examination Laboratory Diagnosis

4. Sample Collection

5. CSF – Lumbar Puncture Blood – i.v . Other samples : For viruses : Nasopharyngeal & Throat swab, Feaces Cobweb appearance (Tubercular) Samples to be collected

6. Lumbar Puncture CSF Collection

7. Contraindications Local skin infections Suspected spinal cord or i/c mass lesion bleeding diathesis Spinal column deformities Non-cooperation of patient Lumbar Puncture

8. Stylet Needle Black – 22 G Yellow – 20 G Spinal Needle Lumbar Puncture

9. STEP 1 PATIENT’S CONSENT IS TAKEN Lumbar Puncture

10. STEP 2 PATIENT POSITIONING Lateral lying position Sitting position Lumbar Puncture

11. STEP 3 LANDMARKING PUNCTURE SITE Line joining Post. Sup. iliac crests intersects Midline at Spinous process of L4 Lumbar Puncture

12. STEP 4 CLEANING SITE WITH ANTISEPTICS First Iodinated antiseptics Then, Isopropyl alcohol Lumbar Puncture

13. STEP 5 LOCAL ANAESTHESIA 1% Lidocaine without Epinephrine Lumbar Puncture

14. STEP 6 SPINAL NEEDLE INSERTION Lumbar Puncture

15. Lumbar Puncture

16. STEP 7 CSF COLLECTION IN 3-4 TEST TUBES TUBE 1 Glucose Protein TUBE 2 Gram stain Culture TUBE 3 Cell count TUBE 4 For special tests (2-5 mL each) Lumbar Puncture

17. STEP 8 REMOVAL OF NEEDLE AND APPLYING BANDAID Lumbar Puncture

18. Transport of Specimen

19. Immediately hand-delivered Never refrigerated ( H.Inf may die) Transport of Specimen

20. Initial Processing

21. One Portion Centrifugated at 3000 rpm/5min Other portion left uncentrifuged SUPERNATANT DEPOSIT UNCENTRIFUGED CENTRIFUGED for Antigen detection , Biochemical Analysis for Direct Microscopy , Culture for Cell count Initial Processing

22. Examination

23. Cell Count Biochemical Analysis Direct Microscopy Culture Antigen Detection Examination

24. Diagnosis Total Cells (per mm 3 ) Predominant cell Proteins (mg/ dL ) Glucose (mg/ dL CSF Pressure (mm Hg Normal CSF 0-5 Lymphocyte 15-45 40-80 70-180 Pyogenic Meningitis ↑↑ ed (5-20,000) Polymorph ( Neutrphl ) ↑↑↑ ed (>100) ↓↓ ed ↑ ed Tubercular Meningitis ↑ ed (5-2,000) Lymphocyte ↑↑ ed (>45) ↓ ed ↑ ed Viral Meningitis ↑ ed (5-2,000) Lymphocyte ↑ ed (>45) Normal ↑ ed or Normal Cell count & Biochemical

25. Direct Microscopy Using part of sediment Two types : Dry Smear Wet film

26. Direct Microscopy Dry Smear Gram + ve Gram - ve C. neoformans India ink Stain M. tuberculosis Ziehl-Neelsen Gram Stain

27. Direct Microscopy Wet Films Acanthamoeba Cryptococcus

28. Culture CSF culture using sediment For Pyogenic Bacteria : Blood Agar Macconkey Agar Chocolate Agar Brain-Heart Infusion Broth For M. tuberculosis : Lowenstein-Jensen (LJ) Middlebrook media For fungi : Sabouraud dextrose agar (SDA) Incubated at 37 o C for 48-72 hours Incubated at 30 o C for 8 weeks Incubated at 30 o C for 3 weeks

29. Culture MacCconkey Agar (LF) Blood Agar (Str. Pneumoniae ) Pink circular colonies Small, dome-shaped with greenish discolouration ( α - hemolysis )

30. Culture Chocolate Agar (H. Influenzae ) Brain-Heart Infusion Broth (Fastidious bacteria) Small opaque colonies

31. Culture Lowenstein-Jensen Medium (Egg based) Middle-brook Medium (Agar based) Dry, Rough, Tough, buff coloured colonies Granular colonies

32. Culture SDA medium (Cryptococcus) Smooth, Mucoid , Cream- coloured colonies

33. Culture Blood Culture Useful in meningitis due to : N. meningitidis H. influenzae Str. Pneumoniae Special Culture/isolation techniques If Viral/ Protozoal /Fungal meningitis is suspected

34. Confirmatory Tests For confirmation Microscopy and biochemical reactions Serological techniques Other confirmatory tests depending on the organism

35. Rapid Diagnosis

36. Rapid Diagnosis Supernatant fluid contains Antigen Detected Serologically Rapid Diagnostic Test for Meningitis Methods : Latex Agglutination , Counterimmunoelectrophoresis (CIEP)

37. Rapid Diagnosis Available for : N. meningitidis , Str. Pneumoniae , H. influenzae type b Group B streptococcus

38. Rapid Diagnosis Latex Agglutination Test Slide AGGLUTINATION occurs Antigen Polystrene Latex Particles Antibody coated Supernatant

39. Rapid Diagnosis Counter- immuno -electrophoresis Antigen Antibodies Supernatant Slide Agarose layer Wells cut on surface - + Electric Current is applied PRECIPITATION LINE forms

40. Relax !!! Thank you…