Tietze Chapter 5 Diagnostics (Respi, Biomarkers)

Bronchoscopy

It is used to visualize the tracheobronchial tree. A flexible bronchoscope is introduced into the tracheobronchial tree through the nose, mouth, or endotracheal or tracheotomy tube. Samples of fluid and tissue may be obtained for Gram staining, culture, and cytologic examination

Thoracentesis

IT is the procedure that is used to obtain a sample of pleural fluid for analysis. The fluid is assessed for each of the following characteristics

• Blood

• Yellow

• Green

• Black

PLEURAL FLUID ANALYSIS

• — is associated with trauma, malignancy, and pulmonary infarction.

• A straw — color is associated with a transudate.

• A — color is associated with biliopleural fistula.

• A — color is associated with Aspergillus niger infection.

• Pus

• Turbid

• Viscous

PLEURAL FLUID ANALYSIS

• — is associated with an empyema.

• A — fluid is associated with inflammatory exudates or lipids.

• A — fluid is associated with mesothelioma.

• Ammonia-like

• Putrid

PLEURAL FLUID ANALYSIS

• An — odor is associated with urinothorax.

• A — odor is associated with infection with anaerobic organisms.

Spirometer

Pulmonary function testing is performed using spirometry or body plethysmography.

• It detects and records changes in lung volume and flow

Body plethysmography

Pulmonary function testing is performed using spirometry or body plethysmography.

• It detects changes in intrathoracic pressure and volume.

Carbon monoxide diffusing capacity

The test is a noninvasive test of lung function. DLCO is an index of the surface area available for gas exchange and is decreased in emphysema, alveolar inflammation, and pulmonary fibrosis.

Forced expiratory volume in 1 second (FEV1)

• It is the volume of air (in liters) exhaled in the first second during forced exhalation after maximal inspiration. Normally, at least 80% of the forced vital capacity (FVC) is exhaled in the first second.

• It is used with the FVC to differentiate between obstructive lung disease and restrictive lung disease

Forced Vital Capacity FVC

It is the total volume of air (in liters) blown out of the lungs during forced exhalation after maximal inspiration.

peak expiratory flow rate (PEF, PEFR

IT measures the forced expiratory flow in liters per minute. It is used to monitor disease progression and response to therapy in patients with bronchospastic diseases such as asthma.

30%

PEF variability of greater than — indicates moderate to severe persistent asthma

residual volume (RV)

• The — is the volume of air remaining in the lungs after forced expiration. It is measured with body plethysmography.

• They are increased in diseases characterized by small airway obstruction (e.g., asthma).

Tidal volume (TV)

— is the volume of air inspired or expired in normal breathing.

Pulse oximetry

is a noninvasive transcutaneous technique used to assess oxygen saturation.

Quantitative pilocarpine iontophoresis (Sweat test)

• It measures the concentration of sodium in sweat after stimulation of the sweat glands with topical pilocarpine; low-voltage current is applied to aid in the absorption of the pilocarpine.

• It is used in the diagnosis of cystic fibrosis.

Ventilation/Perfusion Scanning

• It is used to compare ventilation and perfusion. Images of the airways taken after the inhalation of radiolabeled tracers are compared with images of the pulmonary vasculature taken after the injection of contrast agents.

• Normally, ventilated and perfused areas match. This test is commonly used to identify pulmonary emboli.

BIomarker

• a characteristic that is measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic response to a therapeutic intervention.”

• In the broadest sense, it is any clinical biologic measure

Proximal biomarker

biomarker that occurs early in the pathophysiologic cascade

Distal biomarker

biomarker that occurs late in the pathophysiologic cascade

Preventive biomarker

biomarker that prospectively identifies risk of disease

Diagnostic biomarker

biomarker that identifies the disease before any clinical signs or symptoms appear

Prognostic biomarker

biomarker that stratifies the risk of disease progression

Predictive biomarker

biomarker that prospectively identifies patient response to therapy

Surrogate end point biomarker

biomarker that substitutes for a clinical end point

• CK MB

• Troponins

Well-established cardiac biomarkers for detecting an acute myocardial infarction (AMI) include

• Atrial natriuretic peptide (ANP), Brain natriuretic peptide (BNP)

—, secreted by the heart, regulate blood pressure and body fluid balance by antagonizing the renin-angiotensin-aldosterone system and the sympathetic nervous system.

C-reactive protein CRP

—, a protein synthesized by the liver in response to cytokine stimulation, reflects ongoing inflammation and is predictive of increased risk of AMI.

QT interval prolongation

---

often precedes potentially fatal ventricular arrhythmias but has low sensitivity and specificity for torsades des pointes (TDP

• CEA

• Alpha fetoprotein

• PSA

• CA125

• CA19-9

CANCER BIOMARKERS

• Colorectal cancer

• Primary liver carcinoma

• Prostate cancer

• Ovarian carcinoma

• Pancreatic/gastric carcinoma

• BRCA1

• BRCA2

These gene mutations are used as screening markers to identify patients at increased risk for developing breast and ovarian cancer.

• Serum BUN

• Creatinine

What are the well established kidney biomarkers

Cystatin C

• is a cysteine protease inhibitor that is freely filtered by the glomeruli, resorbed in the proximal tubule, and not affected by muscle mass, age, or race.

• Serum levels may predict glomerular function better than serum creatinine concentration.

Kidney injury molecule 1 (Kim1)

IT is a renal tubular protein and is a very early indicator of kidney damage.

Neutrophils gelatinase-associated lipocalin (NGAL)

It is one of the proteins found earliest in the blood and urine after acute kidney injury.

IL-18

It is a specific early marker of acute tubular necrosis.

CSF levels of Tau protein

These may be useful for identifying patients with mild cognitive impairment that may progress to Alzheimer’s disease (AD).

• Endotoxin

• TNF

• IL-6

• Procalcitonin (PCT)

• CRP

Although more than 100 biomarkers have been identified as potentially useful indicators of sepsis, none is currently sensitive or specific enough to be clinically applicable.17 Biomarkers of interest include: