Typical CSF Findings in Patients with Meningitis PDF

MICROBIOLOGY AND PARASITOLOGY TYPICAL CSF FINDINGS IN PATIENTS WITH MENINGITIS Dr. Fritz Von T. Gella, RMT, MD | September 18, 2024 ❖ Choroid Plexus OUTL...

MICROBIOLOGY AND PARASITOLOGY TYPICAL CSF FINDINGS IN PATIENTS WITH MENINGITIS Dr. Fritz Von T. Gella, RMT, MD | September 18, 2024 ❖ Choroid Plexus OUTLINE Main producer of cerebrospinal fluid (CSF) I. Typical CSF Findings II. CSF Specimen Collection Located in the ventricles of the brain in Patients with A. Specimen ❖ Ependymal Cells Meningitis Collection Not part of the choroid plexus A.Introduction B. Clinical Do not produce CSF B.Formation and Significance of Play a crucial role in the circulation and Physiology CSF Appearance movement of CSF throughout the central C.Flow of CSF C. Cell Count nervous system D.Production of CSF D. Chemistry Tests These cells line the ventricles and the E. Microbiology Tests central canal of the spinal cord, facilitating F. Limulus Amebocyte the distribution of CSF Lysate Test G. Summary FLOW OF CEREBROSPINAL FLUID (CSF) I. CEREBROSPINAL FLUID 1. Choroid Plexus: CSF is produced in the choroid plexus located in the two lumbar ventricles, third, INTRODUCTION and fourth ventricles. Major fluid of the body 2. Lateral Ventricles: CSF flows from the choroid Provides a physiologic system to supply nutrients to the plexus in the lateral ventricles into the nervous tissue interventricular foramen (Foramen of Monroe). Remove metabolic wastes 3. Third Ventricle: CSF enters the third ventricle, Produce a mechanical barrier to cushion the brain and where more CSF is added from its own choroid spinal cord against trauma plexus. 4. Cerebral Aqueduct: CSF flows through the cerebral aqueduct (Aqueduct of Sylvius) into the FORMATION AND PHYSIOLOGY fourth ventricle. The brain and spinal cord are lined by the meninges, which 5. Fourth Ventricle: CSF is produced in the choroid consists of three layers: plexus of the fourth ventricle. 1. Dura mater (Latin for “hard mother”) 6. Foramina of Luschka and Magendie: CSF exits 2. Arachnoid (“spiderweb-like”) the fourth ventricle through the lateral (Foramina of 3. Pia mater (Latin for “gentle mother”) Luschka) and medial (Foramen of Magendie) apertures into the subarachnoid space. 7. Subarachnoid Space: CSF circulates around the brain and spinal cord in the subarachnoid space. 8. Arachnoid Villi: CSF is absorbed into the venous system through arachnoid villi (granulations) that project into the dural sinuses. 9. Venous Circulation: Finally, the absorbed CSF enters the bloodstream via the venous system. PRODUCTION Choroid plexuses of the lateral ventricles and 3rd and 4th ventricles 20ml is produced/hour Total volume ○ Adults: 90-150mL ○ Neonates: 10-60mL HYDROCEPHALUS – a condition marked by an abnormal accumulation of cerebrospinal fluid (CSF) in the brain's ventricles, leading to increased intracranial pressure. II. CSF SPECIMEN COLLECTION CSF is routinely collected by lumbar puncture between the third, fourth, or fifth lumbar vertebra. Precautions: ➔ Measurement of intracranial pressure ◆ High Intracranial Pressure (ICP): conditions such as severe meningitis, intracranial hemorrhage, or tumors can elevate ICP. ◆ Collecting cerebrospinal fluid (CSF) with high ICP can create a pressure differential. Transcribed by: NMD 2027  Typical CSF Findings in Patients with Meningitis ◆ This may lead to brain herniation, pushing brain tissue through the foramen magnum. ➔ Careful technique to prevent infection or neural tissue damage Anatomical Landmarks for CSF Collection: 1. Iliac Crests: ○ The iliac crests can be palpated and serve as a reference point. The line connecting the highest points of the iliac crests typically corresponds to the level of the L4 vertebra. 2. L3-L4 or L4-L5 Intervertebral Space: ○ The needle is inserted into the intervertebral space between L3 and L4 or L4 and L5. This is the safest and most common site for lumbar puncture. CLINICAL SIGNIFICANCE OF CSF APPEARANCE Appearance Cause Major Significance Crystal Clear NORMAL WBCs Meningitis Microorganisms Meningitis Hazy, turbid, Disorders affecting milky, cloud blood-brain barrier Protein Production of IgG Specimens are collected in three sterile tubes, which are within the CNS labeled 1, 2, and 3 in the order in which they are withdrawn. Radiographic Oily contrast media CSF COMMON Hemorrhage, TUBE STORAGE Bloody RBCs ANALYSIS TESTS Traumatic Tap Glucose levels; Protein Chemical and levels; 1 Serologic Lactate Frozen Tests levels; Immunoglobul in levels Cultures for bacteria, fungi, and mycobacteria; 2 Microbiology Polymerase Room Temp chain reaction (PCR) for viral pathogens White blood cell (WBC) count; Red Hematology/ blood cell 3 Refrigerated Cell Count (RBC) count; Differential count (types of WBCs) Any additional assays that Additional 4 may be Tests requested by the clinician 2 of 8  Typical CSF Findings in Patients with Meningitis Image: A- Pleocytosis – increased number of white blood cells in the CSF (refer to image below) ○ Abnormal CSF - finding of immature WBCs, eosinophils, plasma cells, macrophages, tissue cells and malignant cells Red box: highlighted based on Doc Von’s lecture. Image shows PLEOCYTOSIS (black arrows) Image with red circle: If the CSF is left to stand, a fine clot Lymphocytes, Monocytes and Neutrophils = resembling a pellicle or cobweb may form. Meningitis Neutrophils = Bacterial Lymphocytes and Monocytes = Tubercular, Viral, CELL COUNT Fungal and Parasitic meningitis 3RD TUBE Early stage (1-2days) of viral, fungal, tubercular and Normal CSF: Lymphocytes and Monocytes parasitic meningitis – Increased Neutrophils ○ Adults: 70:30 Lymphocytes to Monocytes (70L, 30M) ○ Children: 30:70 Lymphocytes to Monocytes (30L,70M) ○ Occasional neutrophils may be seen 3 of 8  Typical CSF Findings in Patients with Meningitis CSF GLUCOSE 60-70% of the plasma glucose Blood collection should be done 2 hours before the spinal tap. For accurate measurement of the CSF glucose, plasma glucose should be run simultaneously. CSF LACTATE Less than 25 mg/dL Elevated in bacterial, fungal and tubercular meningitis >35mg/dL : Bacterial meningitis Less than 25mg/dL : Viral meningitis Falls rapidly when treatment is successful= sensitive method for evaluating the effectiveness of antibiotic therapy. CSF GLUTAMINE CHEMISTRY TESTS [1ST TUBE] Produced from ammonia and α-ketoglutarate by the brain cells Serves to remove the toxic metabolic waste product ammonia from the CNS Elevated levels are associated with liver disorders that result in increased blood and CSF ammonia. MICROBIOLOGY Positive identification of the causative agent of the meningitis (Culture – gold standard) CSF PROTEIN The spinal fluid normally contains very little protein 24 hours result with bacterial meningitis to 6 weeks in since serum proteins are large molecules that do tubercular meningitis not cross the blood-brain barrier. Most of the protein that is normally present is Other tests: Gram staining, Acid fast staining, India ink and albumin. Latex agglutination test Normal CSF protein: 15-45 mg/dL Serum protein : 65-80 g/dL 4 of 8  Typical CSF Findings in Patients with Meningitis MICROBIOLOGY: GRAM STAIN Cryptococcus Performed on concentrated specimens because Gram stain for the classic STARBURST pattern produced by often only a few organisms are present at the onset Cryptococcus of the disease CSF should be centrifuged at 1500 g for 15 minutes MICROBIOLOGY: ACID FAST STAINING Slides and cultures should be prepared from the sediment Tubercular meningitis GRAM STAINING Gram staining Streptococcus pneumoniae Haemophilus influenzae Escherichia coli Neisseria meningitidis Streptococcus agalactiae MICROBIOLOGY: INDIA INK Fungal meningitis are Gram stained and often have an India ink preparation performed Detect the presence of thickly encapsulated Cryptococcus neoformans 5 of 8  Typical CSF Findings in Patients with Meningitis FREEDOM WALL LIMULUS AMEBOCYTE LYSATE TEST Simple method for the detection of viable and non- viable Gram-negative bacteria Reaction between LPS and a substance (clottable protein) contained within amoebocyte cells derived from the blood of the horseshoe crab SUMMARY 6 of 8 Typical CSF Findings in Patients with Meningitis 7 of 8 Specimen Collection 8 of 8