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Body Fluids. Fluids. CSF Pleural Fluid Peritoneal Fluid. Pt with fever, nuchal rigidity. Get blood cx Give Abx S. pneumo (30-50%), N. Meningitidis (10-35%), H. influenza (<5%), Listeria (5-10%), Staph Ceftriaxone 2mg IV q12h for GPC, GNR Vanc 1g IV BID for PCN-resistant Strep pneumo
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Fluids • CSF • Pleural Fluid • Peritoneal Fluid
Pt with fever, nuchal rigidity.... • Get blood cx • Give Abx • S. pneumo (30-50%), N. Meningitidis (10-35%), H. influenza (<5%), Listeria (5-10%), Staph • Ceftriaxone 2mg IV q12h for GPC, GNR • Vanc 1g IV BID for PCN-resistant Strep pneumo • Ampicillin for Listeria (in elderly, young) • Decadron 0.4mg/kg IV q12 if concern for Bact infxn • Give with first dose of Abx! • Improves mortality, reduces incidence of hearing loss • R/O increased ICP w/Head CT if needed • Lumbar puncture ** Do not delay antibiotics waiting for CT or LP results **
Who to LP? Indications • Fever, vomiting, HA, photophobia, altered level of consciousness, leukocytosis, meningeal signs...to r/o infection, malignancy Contraindications • INR > 1.5 • Platelets < 50,000
Risks of LP First Do No Harm... • Post-lumbar puncture HA • Have pt lie down 1-3 hrs after the procedure to prevent CSF leak • Bleeding; spinal hematoma • Infection (poor sterile technique) • Herniation
Contraindications • infection at desired puncture site • - obstructive / non-communicating hydrocephalus • - intracranial mass • - high intracranial pressure (ICP) / papilledema (relative contraindication, depends on etiology, especially with intracranial mass lesion secondary to the increased risk of transtentorial or cerebellar herniation) • - focal neurological symptoms/signs, decreased level of consciousness (LOC) (see CT before LP section below) • - partial / complete spinal block • - acute spinal trauma
WHEN TO GET A CT FIRST • The absence of all these features makes a significant lesion precluding LP very unlikely: • 1) Age > 60 yrs • 2) Immuno-compromised state (e.g. HIV) • 3) History of CNS disease (eg. grand mal seizures, brain tumour, hydrocephalus, multiple sclerosis) • 4) Seizure within one week of presentation • 5) Abnormal LOC • 6) Unable to answer two questions correctly or follow two commands • 7) Abnormal neurological examination (visual field defect, facial palsy, pronator drift, aphasia)
Lumbar Puncture Procedure • Pt lies in L lateral decub position, knees to chest • Aim for the L3-L4 or L4-L5 intervertebral space • Posterior iliac crest as marker for L4-L5 space • Spinal cord ends L1-L2 • Prep/drape lower back in sterile fashion...lidocaine • Insert LP needle pointing towards umbilicus with the bevel up, advance until “pop” • Obtain opening pressure (only if pt lying down) • Fill tubes #1-4 with CSF
CSF Evaluation • Tube 1-cell count and differential • Tube 2-glucose, protein • Tube 3-cultures, gram stain, cytology, “other” studies (HSV PCR, West Nile, India ink, Crypto Antigen, VDRL, Lyme Ab, AFB, etc…) • Tube 4-cell count and differential
Normal CSF values • Clear color • < 5 RBC’s • < 5 WBC’s • Protein 23-38mg/dl (alt. 14-45) • Glucose - 60% of serum level (75-100)
Opening pressure • Normal = 80-180 mmHg • Obese pts: up to 250mmHg can be normal • Pathologically elevated: > 250mmHg • If elevated, likely due to cerebral edema from intracranial pathology • Infection (cryptococcal meningitis), tumor, benign ICH (pseudotumor)
RBCs Always send tube #1 and #4 for cell count and compare RBCs Traumatic tap: Elev RBC in tube 1, nl in tube 4 • The RBC : WBC ratio should be the same as it is in the blood if it is due to a traumatic tap (Approx 1000 RBC : 1 WBC) • Can find both values in the CBC (RBCs are in millions and WBCs are in thousands) SAH or HSV: Elev RBC in tube 1 AND tube 4 • “Crenated RBCs” and xanthochromia (yellow supernatant after centrifuge) • Seen in hyperbilirubinemia (ESLD), old SAH, old blood from prior traumatic LP or bleed
WBC’s • Infection! • PMN predominance: likely bacterial meningitis • Lymphocytic predominance: viral vs. fungal vs. TB vs. malignancy
Protein • Normal: protein is excluded from CSF by blood-CSF barrier • Increased: nonspecific • Elevated in all infectious meningitis • May remain elevated for months post-meningitis (viral or bacterial) • Increased in malignancy and inflammatory conditions (ex. Guillain-Barre)
Glucose Normal • Viral infection Low glucose • Bacterial meningitis, TB, fungal Really low • < 18 is strongly suggestive of bacterial meningitis
Typical Viral Meningitis • CSF WBC elevated, but < 250 (PMNs in early disease, then lymphocytes) • CSF protein elevated, but < 150 • Glucose > 50% of serum concentration
Typical Bacterial Meningitis • CSF WBC > 1000, PMN predominance • CSF protein > 500mg/dl • CSF glucose < 45 mg/dl
Example • A previously healthy 33-year-old lawyer presents to the ER with acute onset headache and confusion. He develops generalized seizures in the ER. He is treated and sent for a head CT, which shows bilateral hemorrhage in the temporal lobes (and no hydrocephalus). • CSF: mild pleocytosis (mostly lymphocytes), gluc= 60, protein = 30 a) Arbovirus encephalitis b) CNS toxoplasmosisc) Echovirus encephalitisd) Herpetic encephalitise) Metastatic melanoma
HSV Meningoencephalitis • Aseptic meningitis: CSF w/mild ↑ lymphs, nl gluc, nl prot • Most common etiologic agent of sporadic viral encephalitis • Previously healthy pt with rapid onset of confusion and seizures • CT: hemorrhagic necrosis of the temporal lobes • Arbovirus encephalitis: most important cause of epidemic viral encephalitis; clinical course is milder and prognosis is better than herpetic encephalitis • CNS Toxo: in immunocompromised pts; round, ring-enhancing intracerebral masses • Echovirus encephalitis: common cause of asceptic meningitis; mild symptoms (headache, malaise) with normal CSF • Metastatic melanoma: CNS lesions may hemorrhage; but mets appear as space-occupying masses
Example #2 • A 47 year-old male with HIV/AIDS (CD4 = 15), noncompliant with meds, presents with altered mental status. He has had progressively worsening neck stiffness, photophobia, and confusion over the past several weeks. On exam he appears somnolent and confused. You perform an LP, opening pressure is 290 mm Hg, and you see the following slide in the micro lab.
Example #2 • What is the diagnosis? a) Herpes encephalitis b) Disseminated histoplasmosis c) Cryptococcal meningoencephalitis d) Strep pneumo meningitis e) Tb meningitis
Cryptococcus neoformans • Fungal infection seen in immunodeficiency & immunosuppression, esp. in organ transplants and AIDS (CD4 < 50). Signs/sxs of meningitis, but MS changes signify encephalitis. Direct visualization of encapsulated budding yeast in CSF with India Ink stain. Can also see elevated opening pressure and positive crypto antigen in the CSF or serum. Requires lifelong suppressive fluconazole, at least until CD4s are reconstituted. • HSV encephalitis is seen in immunodeficiency, but the organisms are not typically seen on microscopy. • Histoplasma is seen in pulmonary infections locally, but can disseminate to bone marrow, liver… • Strep pneumo is an encapsulated bacterium that can cause meningitis. Signs/sxs and CSF analysis is c/w bacterial meningitis (PMNs, ↓ glucose, etc) • Mycobacterium tuberculosis can cause CNS disease with similar presenting symptoms, but acid-fast organisms are seen on CSF examination.
Example • Pt with AIDS on Combivir (AZT/3TC) and Indinivir c/o leg weakness, incontinence. On exam, reduced strength in lower extremities with mild spasticity. Also diminished sensation in b/l feet, legs. Brain MRI: nonfocal • CSF: Opening pressure=100 mm H20, Cell count=5 lymphs, Glucose=48, Protein=33 Normal serum B12, negative serum RPR, hct nl. • What’s he got? A. AIDS dementia complex B. CMV polyradiculopathy C. Cryptococcal meningoencephalitis D. Vacuolar (HIV) myelopathy E. AZT neurotoxicity
HIV Myelopathy • Common neurologic complications of AIDS • Degeneration of spinal tracts in posterior, lateral columns (causing them to look vacuolated) • Physical findings are similar to B12 deficiency • Diagnosis of exclusion! • AIDS dementia complex: progressive memory loss, alterations in fine motor control, urinary incontinence, altered mental status • CMV polyradiculopathy: CSF has neutrophilic pleocytosis • Crypto meningoencephalitis: presents with signs/symptoms of meningitis, and CSF shows fungus • Zidovudine-related toxicity: can cause asthenia, myopathy
Thoracentesis Indications • Diagnostic - All NEW effusions (except if clearly due to heart failure) • Suspected parapneumonic effusions must be tapped ASAP (“Don’t let the sun set on a new pleural effusion”) • Therapeutic – Respiratory distress
Don’t do Thoracentesis if... • Coagulopathy (INR > 2, platelets < 25,000) • Severe lung disease on contralateral side (risk of PTX – then what do you have left?) • Mechanical ventilation (not due to risk of PTX from PEEP, but due to decreased re-sealing)
Loculated? • Must be > 1 cm and free flowing in lateral decubitus view • If CT shows free-flowing fluid, you don’t also need lateral X-ray
Thoracentesis Procedure • Confirm fluid is free-flowing, not loculated • Obtain consent • Consider US mark if medium-size effusion or loculated • Have pt sitting up and leaning forward over table to spread the scapulae out of the way • Percuss fluid level and go 1-2 rib spaces below, in midclavicular line • Enter just ABOVE the rib to avoid neurovascular bundle • ALWAYS obtain a post-procedure CXR
Pt gets dyspneic after you’ve withdrawn 150cc from L chest....
You took 2.3L clear fluid off this pt’s Right chest. F/u CXR shows....
Other Thoracentesis Complications • PTX • Re-expansion pulmonary edema • Don’t take off more than 1.5 L • Hemothorax • Infection • Hypotension • Hepatic or Splenic puncture
What to order? Serum LDH, total protein Pleural fluid: • Total Protein, LDH • Glucose, cell count and diff, pH (on ice) • Gram stain, culture, fungal stain and culture, AFB • Cytology • Other: triglyceride level to r/o chylothorax; amylase to r/o pancreatitis, esoph perf; Adenosine deaminase (ADA) to eval for Tb pleuritis
Light’s Criteria Fluid is exudative if it meets ANY criteria: 1. Pleural fluid LDH/serum LDH > 0.6 2. Pleural fluid protein/serum protein > 0.5 3. Pleural fluid LDH > 2/3 upper limit of normal serum LDH • If all 3 negative, fluid is transudative
Transudate • Result from imbalances in oncotic and hydrostatic pressure • Usually low serum oncotic pressure +/- high serum hydrostatic pressure • Pulm Edema/CHF • Cirrhosis with ascites • Hypoalbuminemia/Nephrotic syndrome, ESLD • Fluid overload s/p aggressive IVF • Peritoneal dialysis
Exudate Caused by local, not systemic, factors • Infection • Neoplasm • Pancreatitis • Esoph perf • RA • SLE • Sarcoid, Wegeners, PE, Meig’s, Chylothorax
Lymphocytosis • Malignancy (50-70% lymphs) • Also TB, sarcoid, RA, chylothorax (>90% lymphs)
Pneumothorax Hemothorax Pulm infarct Parasitic disease Fungal infection Drugs Malignancy Asbestos Pleural eosinophilia
Why is glucose low?(<60) • RA • TB • Empyema • SLE • Malignancy • Esophageal rupture
Who needs a chest tube? Empyema • Frank pus OR • Positive gram stain OR • pH < 7.0 (consider when pH < 7.2)
Parapneumonic Effusions • Alternate to pH is pleural glucose (< 60) • ACCP recommendations, from Chest, 2000
Parapneumonic Effusions • Treatment: • Small, free-flowing, uninfected effusions (category 1/2) may not require any drainage, or serial thoracentesis. • Complicated effusions and empyemas (category 3/4) require drainage and intervention • Chest tube • Fibrinolytics • VATS • Surgery
Example • A 59-year old man with HIV and Hepatitis C develops progressive SOB and presents to the ER with 90% sats on RA. On CXR, he has a large right-sided pleural effusion. • Serum LDH=200, serum protein = 5.6. • Pleural fluid: LDH 100, protein 2700, WBC 400, pH 7.35, glucose=85 • Exudate or transudate? Retap? Abx? Chest tube?
Pleural fluid LDH/serum LDH=100/200= 0.5 • needs to be > 0.6 to be exudate • Pleural fluid protein/serum protein=2700/5600= 0.4 • needs to be > 0.5 to be exudate • Pleural fluid LDH is < 2/3 x (ULN serum LDH) • Transudate • Cause is cirrhosis/ascites • Presents w/right sided pleural effusion • No Abx or need to retap • Treat the underling problem (ascites) w/ diuretics, aldactone; optimize treatment for Hep C, HIV
Example • A 34 y.o. woman with cystic fibrosis presents to the ER with fever, cough and night sweats for 10 days. CXR shows LLL consolidation and surrounding free-flowing effusion. • The lab loses tubes for serum LDH, protein • Pleural fluid: cloudy, LDH=1360, pH=6.9, gluc = 36, gram stain neg • Does she need a chest tube? Fibrinolytics?