Lab med test 3 lecture 15

Bacteremia

is the presence of bacteria in the blood; can be intermittent and transient. Typically manifests as fevers/chills.

- Must obtain two culture specimens from two different sites

- Preferably obtain prior to initiation of antibiotics

- If antibiotics are given prior to blood cultures drawn, notify lab

- 24 to 72 hours for organism growth and identification

Blood culture rules:

•Contamination of blood by skin flora may occur

what are interfering factors for blood cultures

- Suspected sepsis

- Unexplained illness

- Fever of unknown origin

- Severe localized infection (c/f spread to bloodstream)

- Patients with indwelling catheters (central lines, PICC lines, ports)

- Endocarditis (monitor response to therapy)

when would you get a bacteria culture

- temp >38 C or < 36 C

- HR >90

- RR >20 or PaCO2 <32

- WBC >12000 or <4000 or >10% bands

what is the SIRS criteria

sepsis

SIRS + Infection =

Lumbar Puncture

medical procedure used to collected cerebrospinal fluid for diagnostic or therapeutic purposes

- Opening Pressure

- Color

- WBC count + differential

- RBC count

- Culture and sensitivity

- Protein

- Glucose

- Cytology

what studies are available for lumbar puncture and CSF exaimination

gram stain results bc speciation and sensitivity/resistance from culture results take longer

when you first get a blood culture result what due you first receive

- The lowest concentration of an abx that can inhibit the growth of a specific microorganism.

- The lower the MIC, the more effective the abx is against the microorganism.

- Choose an abx that has a MIC BELOW the achievable drug concentration.

what is the minimal inhibitory concentration

Stool cultures

_____ _____are laboratory tests used to facilitate the growth of pathogenic bacteria, parasites, and fungi from a patient's stool

- Urine may inhibit growth of bacteria

- Recent barium studies may obscure detection of parasites

- Recent antibiotic use, bismuth, mineral oil use = disrupt results

what are interfering factors for Stool cultures

Arthrocentesis

Needle inserted into a joint space to aspirate synovial fluid or inject medications

indication on when to

hyperbilirubinemia, other

Yellow tinge for lumbar puncture

elevated WBCs or protein

Cloudy appearance may indicate what in a lumbar puncture

presence of blood

Red tinge may indicate what in a lumbar puncture

abnormal color of CSF

Xanthochromia

- Meningitis

- Encephalitis

- Autoimmune disease of the CNS

- Neurosyphilis

- Demyelinating disorders

- Cerebral Hemorrhage

when do you order a lumbar puncture

- Elevated intracranial pressure due to mass effect (brain tumor, abscess, hemorrhage)- LP may induce cerebral or cerebellar herniation

- Severe vertebral joint disease

- Infection near LP sight (ex: cellulitis)

- Anticoagulation (risk of epidural hematoma)

when are lumbar punctures Contraindications:

Must get CT head to r/o if signs of elevated ICP

If you suspect a that Elevated intracranial pressure is due to a mass effect what should you do

- Haemophilus influenzae (children)

- Neisseria or Streptococcus (adults)

Most common causes of meningitis Haemophilus influenzae (children) and Neisseria or Streptococcus (adults)

decrease

what happens to glucose when bacteria, inflammatory cells, or tumor cells are present

60% of blood glucose

•CSF glucose levels are less than _______________level may indicate meningitis or neoplasm

- Bloody Diarrhea (dysentery)

- Fever

- LLQ Cramps, urgency, tenesmus

- Bacterial > Viral

- Dx eval = routine stool bacterial tests (culture) + C. Diff and parasite testing (if indicated)

when is diarrhea inflammatory

- Watery (No blood)

- No Fever

- Periumbilical cramps, bloating, nausea, vomiting

- Viral > Bacterial

- Dx eval = limited to pts with severe sxs or sxs > 7 days

when is diarrhea non inflammatory

< 2 weeks

acute diarrhea duration

> 4 weeks

chronic diarrhea duration

viral or tubercular meningitis or encephalitis

Elevated mononuclear leukocytes means

bacterial meningitis or abscess

Elevated Neutrophils means

pathologic due to Infection, autoimmune, malignancy

>1 WBC per 500 RBCS is considered _____

- Meningitis, encephalitis (increases permeability of blood brain barrier)

- CNS tumors (secretes proteins into CSF)

- Autoimmune disease (elevated immunoglobulins)

why would there be proteins in the lumbar puncture

<20 cm H2O

what is normal opening pressure for a lumbar puncture

indicates elevation of intracranial pressure: Tumor, Infection, Hydrocephalus, Intracranial bleeding

if the opening pressure is > 20 in a lumbar puncture what does that mean

overlying skin infection

when would you not want to do a Arthrocentesis with Synovial Fluid Analysis

Establish diagnosis of:

•Joint infection

•Arthritis

•Gout vs. pseudogout

•Synovitis

•Neoplasm of the joint

•Injection of corticosteroids

when would you want to do a Arthrocentesis with Synovial Fluid Analysis

- Joint infection

- Joint hemorrhage

What are some potential complications with Arthrocentesis with Synovial Fluid Analysis

gout

Monosodium crystals in Arthrocentesis with Synovial Fluid Analysis

psuedogout

Calcuim crystals in Arthrocentesis with Synovial Fluid Analysis

gou

elevated uric acid in Arthrocentesis with Synovial Fluid Analysismeans

infection or tramua

low glucuse in Arthrocentesis with Synovial Fluid Analysismeans

inflammation, infections, crystal deposition

elevated proteins in Arthrocentesis with Synovial Fluid Analysis mean

inflammation or infections

low viscosity of Arthrocentesis with Synovial Fluid Analysis means

infection, inflammation, crystal induced arthritis

elevated WBCs in Arthrocentesis with Synovial Fluid Analysis means