PA 654 - DM - Lecture 2 - Fall 2023 - HEENT and Lab Basics PDF
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Uploaded by DiversifiedCatSEye4641
Medical University of South Carolina
2023
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Summary
This document is a medical lecture on HEENT and basic lab procedures, covering topics such as contraindications, complete blood counts (CBC), and diagnostics. It is intended for undergraduate-level students.
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HEENT 70 y/o M retired building contractor presenting w/ sever left eye pain, tearing and photophobia and blurry vision after being kicked in the eye 2 hours ago by 4 year old grandson. Pt. denies floaters, flashes of light, descending curtain or mucous/bloody drainage. HEENT Diagnostics By: John...
HEENT 70 y/o M retired building contractor presenting w/ sever left eye pain, tearing and photophobia and blurry vision after being kicked in the eye 2 hours ago by 4 year old grandson. Pt. denies floaters, flashes of light, descending curtain or mucous/bloody drainage. HEENT Diagnostics By: John Bowers, PA-C Adapted from slides provided by: Matt Ewald & Gilbert A. Boissonneault, PhD, PA-C Division of Physician Assistant Studies Medical University of South Carolina Topics for today: General Introduction– Contraindications, The Complete Blood Count (“CBC”) HEENT- Specific Topics– HEENT (Head): B2 transferrin lab HEENT (Eyes): Slit Lamp & Tonometry Ophthalmological pH evaluation HEENT (Ears/Nose/Throat): Point-of-Care and Immunoaffinity tests Rapid visualization tests (e.g., Rapid Strep, Flu) Sinus puncture and aspiration Rhinoscopy and Rhinolaryngoscopy HPV testing Contraindications Overview Contraindication/Contraindicated If a provider determines that they would like to perform a diagnostic test or procedure, he/she must weigh the risks and benefits with the patient. That person must also consider reasons for which they should not perform a diagnostic test or procedure regardless These are called the contraindications There are two types of contraindications: 1.) Relative contraindication – under certain circumstances, a patient may undergo a test if they meet criteria for a certain relative contraindication (i.e. benefit outweighs risk; or risk can be mitgated) 2.) Absolute contraindication – under no circumstance should you perform a test if a patient has criteria for an absolute contradiction Examples: Relative contraindicationPerformed an MRI on a patient with claustrophobia It is a relative contraindication to perform an MRI on a patient with this condition, but often the benefit outweighs the risk The condition is also manageable and not likely life threatening, but may require treatment (i.e. anxiolytic medication) Absolute contraindicationPerforming an MRI on a patient with metallic implant that is not MRI-compatible The MRI is absolutely contraindicated in any patient with a metal implant that is not MRI-compatible, as this can cause serious injury The benefit does NOT outweigh the risk to the patient and is not easy to mitigate nor manage without causing injury to the patient. CBC – The Complete Blood Count One of the basic building blocks for diagnostic testing Diagnostic Cornerstone #1: The CBC By the end of this course, you should be able to answer: What does a CBC generally assess? Why do we order it? How can it help you in your assessment of a patient? How does the “differential” help? (Often called “CBC & diff”) Complete Blood Count (CBC) What is the CBC? An analysis of the patient’s blood that provides information about the types & numbers of cells in that sample Specifically: red cells, white cells, and platelets. It also provides valuable information about the cellular immune system. It helps to: Evaluating certain symptoms (eg, weakness, fatigue, fever or bruising) Diagnosing or confirm presence of certain conditions / diseases (eg- anemia, infection, leukemia, and many other disorders) Determining the stage or severity of a particular disease (eg- leukemia) The test is commonly performed by an automated machine and results are available promptly, usually within 10-30 mins (dependent on machine) Automated analyzers are widely available. CBC Across the Lifespan Hbg and HCT are highest at birth (20 g/100 mL and 60%, respectively). The values fall steeply to a minimum at age 3 months (9.5 g/100 mL and 32%, respectively). They then slowly rise to “adult levels” around puberty Thereafter, both values are higher in males when compared to females. A normal decrease usually occurs during pregnancy. This resolves shortly after pregnancy. Composition of blood CBC (cont’d) What does it measure? A CBC panel generally includes the following: WBC (white blood cell) count RBC (red blood cell) count Hgb (hemoglobin) & HCT (hematocrit) [often referred to as H&H] MCH (Mean Cellular Hemoglobin) MCHC (Mean Cellular Hemoglobin Concentration) MCV (Mean Cell Volume) RDW (Red Cell Distribution Width) Platelet Count (usually) A “differential” is usually ordered in addition to a CBC, but can also be ordered separately. The Differential (aka “diff”) The differential measures the percentage of each type of white blood cell (WBC) lineage in a blood sample. Specifically- Neutrophils, Lymphocytes (B cells and T cells), Monocytes, Eosinophils, Basophils The differential helps to determine, differentiate, and diagnose if different types of infection, anemia, or leukemias are present. The percentage of each type of cell will change with certain disorders Example: A bacterial infection would cause increase in neutrophil % CBC Normal Ranges Note these values will vary slightly by institution, by reference book, etc. Primary CBC Differential Indications for CBC? There are many indications! So, let’s keep it simple for now: 1) Assess for changes in the White cell number (WBC) suggestive of leukemia, other cancers, immunosuppression, infection, injury, bone marrow suppression, etc.. (2) Assess for changes in Red cell line (RBC, Hgb or Hct) suggestive of anemia, dehydration, certain cancers, bleeding disorders [acute or chronic], polycythemia, sickle cell, thalassemia, nutrition/vitamin deficiencies In short, think of the CBC in terms of RBC’s and/or WBC’s and why a provider would need either one (or both). This should help you determine if you need a CBC. Abnormal Results In certain situations, abnormal CBC values warrant further evaluation with a peripheral blood smear A peripheral smear includes: RBC morphology, WBC differential, platelet count estimation, and identification of immature and/or malignant cells The test is reserved for significantly or unexpectedly abnormal WBC or Hgb/Hct Used particularly in the setting of a suspicion for a blood-based cancers (i.e. leukemia) This is done by a lab technician manually *The main benefit is to allow identification of abnormal cells and other subtleties that may not be detected with automated systems Of note, in many primary immunodeficiency disorders, cell populations are initially normal, and then decline over time. Peripheral smear Are False Results Possible on CBC? Yes If a capillary fingerstick or heelstick technique is used, the hematocrit may be falsely low. Serum can leak out, without RBC’s If the finger stick is “milked,” sludging of the RBCs can create a falsely high hematocrit. Similar can happen if the plunger on a syringe is pulled too hard against an IV catheter Typically occurs if catheter or needle is against or near a valve within the vein HEENT 70 y/o M retired building contractor presenting w/ sever left eye pain, tearing and photophobia and blurry vision after being kicked in the eye 2 hours ago by 4 year old grandson. Pt. denies floaters, flashes of light, descending curtain or mucous/bloody drainage. HEENT Diagnostics Part 1 – The head -Please note: CT, MRI, and X-ray imaging have a place in HEENT testing, but are not commonly used for day-to-day complaints. àExample: Sinusitis – imaging is not required to make this diagnosis -We will discuss CT, MRI, ultrasound, and other imaging in much more detail later in the year. β-2 Transferrin (Beta-two) β-2 Transferrin β-1 transferrin is found in most body fluids, butβ-2 transferrin is a specific variant of transferrin found in cerebrospinal final (CSF) β-2 transferrin is used as a marker of CSF fluid use in the assessment and the diagnosis of cerebrospinal fluid (CSF) leaks (i.e. rhinorrhea or otorrhea). If this occurs, it is usually is the nose or ear canal, usually as a result of head trauma, tumor, congenital malformation, or surgery. This is measured by electrophoresis, followed by confirmatory testing to determine presence of specific proteins. If beta-2 transferrin is detected in a fluid specimen, it is presumed to contain CSF. http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/80351 β-2 Transferrin The presence of beta-2 transferrin band is detectable with as little as 2.5% spinal fluid contamination in a sample of provided fluid. Specimens 1-4 contain only β-1 transferrin (negative for CSF) but specimens 5 & 6 contain both β-1 transferrin and β-2 transferrin (positive for CSF). http://www.medizinische-fakultaet-hd.uni-heidelberg.de/fileadmin/inst_immunologie/immunchemie/Beta2Trf.bmp Clinical Application: A basilar skull fracture resulting from a head injury or fall can cause a CSF leak, often detected by presence of rhinorrhea or otorrhea. (This injury is a fracture of the bone forming the skull base) Testing of the draining fluid can reveal if it is from a CSF source or not. HEENT Diagnostics Part 2 – Diagnostic tools for the eyes The Slit Lamp Patient Provider Description & Use: The slit-lamp is powerful / magnified light that can focus a narrow beam of light upon the various layers of the cornea, the anterior chamber, iris, the lens, and the anterior third of the vitreous chamber. Uses: Allows for up-close and accurate inspection of: Opacities, foreign bodies, inflammation, complaint of irritation, or eye trauma/injuries. It is primarily only able to look at the anterior eye, though can be used in conjunction with special lenses and a dilated examination to inspect the posterior eye (i.e. retina, etc.) Examples of viewing the eye through a slit lamp Tonometry & The Tonopen Tonometry measures intraocular pressure (IOP). The most common instruments used are the Tono-Pen and the Goldmann applanation tonometer. The normal intraocular pressure ranges between 10-20 mmHg. Measurements may vary slightly with corneal thickness. Standard Tonometry via Tonometry Pen Applanation-Type Tonometry In applanation-type tonometry, intraocular pressure is determined by the force required to flatten the cornea. The higher the intraocular pressure, the greater is the force required. Ophthalmological pH Paper Normal pH should be approximately 7.0 Indications/Uses: To detect for pH abnormalities after chemical or other exposures Pearl: Check pH before, during, and after irrigation of any chemical exposure. (until you reach the desired neutral pH) HEENT Diagnostics Part 3 – Diagnostics for the ears/nose & throat Let’s start with visualization… How do we visualize the posterior oropharynx? What about beyond how a tongue depressor can help? What if we want to look down into the throat? In the anterior sinus passages? Rhinolaryngoscopy This is a tool which allows for direct visualization of the anterior and posterior nasal passages and upper airway Simple anterior rhinoscopy can be performed using your portable otoscope A PA or NP can easily be trained on how to do this Posterior visualization requires a more advanced tool Many different brands, types Ex: Storz Rhinoscope ™ , etc. Rhinocopy About Rhinoscopy: Indications: Visualization of epistaxis (identify source), nasal foreign bodies, nasal polyps, angioedema, septal deviations, nasal tumors, examine vocal cords for injury/paralysis/tumors Note: Posterior epistaxis can only be directly visualized using rhinoscope/rhinolaryngoscope Contraindications: Recent trauma [absolute] (due to suspicion that you could worsen a fracture or puncture into a sinus (or worse), patient intolerance [relative] Additional Info:– This test can also provide: Directly apply therapeutics or medication(s); perform a biopsy; or provide chemical, laser, or photocoagulation for epistaxis Epistaxis Nasal polyps or tumors Upper Airway / Vocal Cord Visualization Similar to rhinoscopy, but can be advanced further to see more Vocal Cord Visualization Click on this link to watch larygoscopy of normal vocal cords Click on this link to watch larygoscopy of abnormal vocal cords Play until 0:13-0:14 Warning: flashing lights in this video (Stop before 0:15 to avoid this) Break Time Point-of-Care Testing (POCT) Convenient, fast results for a multitude of practice settings Rapid Antigen/Antibody Testing (Other terms: Immunoassay / Immunoaffinity Testing) These tests rely on the analyte (the component we want to measure) being bound to an antibody (provided as one of the test components) with specific binding affinity for the analyte Through acid or enzyme action, antibodies are bound to colored microparticles to be able to visualize them Chromatography is used to move the analyte over critical test reagents and deliver them to analyte-specific detectors Rapid Antigen/Antibody Testing Apply specimen in test medium Analyte moves up chromatography pad to conjugate pad, where it interacts with (positive) colored microparticle conjugate Absorbent pad helps to pull sample across the test strip Fluid carries analyte to the capture membrane. If analyte binds to colored microparticles, they will bind to the capture membrane on the capture line (which will become visible) for a specific outcome (positive) POC (“Rapid”) Strep Testing This is part of your “bread and butter” clinical decision-making in clinical practice Used to help rule out (or in) Group A - beta-hemolytic Strep (“GAS”) If untreated, can lead to rheumatic fever and other complications Indications for testing? Those with clinical evidence (erythema, edema, and/or exudates) on physical examination of strep throat. And you do not suspect this set of signs/symptoms to be viral in origin Or - Children with minor symptoms of GAS and exposure to an individual with strep at home or school, or a high community rate of infection Collecting a good sample (it’s important) Use a tongue blade and good light source to identify the area of concern where you will collect your sample Use help if necessary (Pt’s mother; a tech; MA; etc) Use culture swab to touch tonsil(s) and posterior oropharynx (in that order, to avoid gagging first, if possible) Two swabs may be necessary if you intend on both rapid testing and submitting a culture (can be done simultaneously) Note: Some tests will not you allow you to use the same swab for both How To Swab Group A Streptococcus Test Add reagents to tube. Swab pharynx. Expose suspected antigen from swab into reagents. Reagent 1 Reagent 2 Place test strip into tube and wait proper time. Negative Test Positive Test Summary: Contraindications to oropharnygeal swab Absolute Contraindications: If Epiglottitis / Croup is suspected (can worsen these by swapping posterior oropharynx) Or for any other reason when upper airway swelling may be a concern Irritation of this area could theoretically worsen swelling and close off the airway! Risk > Benefit Relative Contraindication: If performing this test puts you at risk for injury Ex: highly uncooperative pt who may bite or otherwise injure you Treatment may be indicated empirically based on suspicion for these patients Risk >/< Benefit? When to consider culture for “strep”? Pts suspected of having an acute GAS infection based on exam, history, or both. Note: If throat culture results will not be available for more than 48 hours, rapid strep testing may be the better choice. Additional Note: **A small delay (~48 hrs) in the start of antibiotics DOES NOT increase risk of rheumatic fever.** Due to high specificity (~95%), but lower sensitivity (~70-90%), negative rapid testing should be confirmed with a follow up throat culture. Thus, some patients will be tested with both modalities. Positive patients (due to high specificity do NOT require culture) When performed properly, the sensitivity of throat culture is 9095 % for GAS (this is the standard of dx for acute GAS pharyngitis ) Centor Criteria A tool to help guide your decision making process. When to use? Children with acute pharyngitis, suspected w/ < 3 days onset; the risk of GAS decreases significantly with age into adulthood. Factors to be considered in the decision to perform testing for GAS include: -Age, clinical signs or symptoms, +/- season of year, +/- exposure to an individual with GAS Modified Centor criteria - also known as the McIsaac score https://www.mdcalc.com/centor-score-modified-mcisaac-strep-pharyngitis Rapid Antigen/Antibody, Immunoassay, and Immunoaffinity Testing POCT can be used for many tests : COVID-19 (antigen) Infectious mononucleosis (anti-mono IgM) Influenza (Influenza A and/or B antigen) Urine Pregnancy testing (hCG) Respiratory syncytial virus (RSV antigen) Chlamydia trachomatis (antigen) Helicobacter pylori (anti-H pylori IgG) When referring to these diagnostics, please be as specific as possible. Please Note: “POCT” for Mononucleosis or “Rapid” Pregnancy will not be accepted as answers on quizzes or exams. These are commonly performed in the office to assist in clinical decision-making. HPV Oro-pharyngeal Testing HPV Testing HPV is the leading cause of oropharyngeal cancers HPV Type #16 is responsible for many Knowledge of HPV status of cancers is helpful for prognosis and treatment planning. The gold standard for assessing HPV infection is in situ hybridization or polymerase chain reaction (PCR) to detect HPV DNA. Several biomarkers serve as surrogates for HPV status or be useful in further refining the risk associated with HPV infection. In situ hybridization or Immunohistochemistry (detecting HPV p16 expression) are recommended by the National Comprehensive Cancer Network Obtaining a Tissue Sample for Testing Fine needle aspiration (FNA) is often used to obtain tissue material from head/neck tumors (i.e. nodules or masses). This is a valuable alternative to surgical biopsies. Tissue material may also come from a lymph node FNA or biopsy. Example on the left is using an ultrasound to obtain a FNA from a thyroid nodule. Similarly, for any nodules, masses, or presumed cancers, it is important to obtain a tissue sample to determine if the cells are cancer. This is done via microscopy. Immunohistochemistry (IHC) A slide of tissue is prepared after biopsy Tissue is exposed to antibody against the protein of interest (primary antibody) If protein antigen is present, the primary antibody binds Tissue is then exposed to a secondary antibody with enzyme attached with enzyme substrate added (called “DAB”), which produces colored product under microscopy and indicates presence or absence of the protein of interest http://www.leinco.com/includes/templates/LeincoCustom/images/immunohistochemistry.gif In situ Hybridization of HPV In Situ Hybridization – How? Tissue cells or a histological slide of fixed tissue is used Then: Add fluorescent-labeled small DNA/sequence which is complimentary to the DNA sequence of the gene in question (or RNA probe for binding to RNA sequence) **That DNA sequence binds to DNA if complementary sequence is found in the specimen DNA Unbound probe is washed out, followed by After staining, fluorescence microscopy is used to look for presence/absence of the desired product ISH results: Abnormal example pathology PCR (polymerase chain reaction) PCR can amplify a single DNA molecule one million-fold. The greatly amplified target DNA is subsequently analyzed via other techniques. Can occur in just a few hours and allows for rapid & highly-specific amplification of DNA fragments Clinical applications of polymerase chain reactions (PCR) are vast. It’s clinical utility is greatest in the context of genotyping and sequencing for diagnostic and predictive testing. Examples: HPV testing, gonorrhea/chlamydia bacteria PCR testing, etc. Obtaining a tissue sample via biopsy is an invasive procedure (i.e. we cut/break the skin and temporarily cause harm to the patient for greater good). In situ hybridization, PCR, or IHC can all be used for detection of HPV-containing tumors. Of note, Immunohistochemistry (IHC) for p16 is highly sensitive for HPV-associated tumors. Thus, IHC is recommended for routine use as a representative of HPV status in a patient. Sinus Puncture/Aspiration Just a few points Sinus Puncture and Aspiration Sinus puncture and irrigation allow for removal of thick, purulent sinus secretions After anesthesizing the area with local anesthetic, a sterile needle is placed into the sinus by passing through its bony wall Entry point through hard palate or through nasal wall Purulent fluid may be sampled and/or sinus rinsed with sterile saline Used to: Remove thick, purulent sinus secretions Guide antibiotic selection when empiric therapy has failed or when antibiotic choices are limited Indications: This should not be performed on patients with uncomplicated sinusitis or sinus infection. Not routinely performed It is, however, indicated if for: Complicated or treatment-resistant infection Typically defined as persistent symptoms despite previous treatment May suggest drug-resistant microorganism This procedure may be of particular importance in patients who are immunocompromised (can be a source of systemic infection/sepsis) Contraindications: Contraindications: Simple sinusitis, trauma/injury to the area of needle insertion, if risk of bleeding outweighs benefit (those on blood thinners) Risks? (Should be performed by a trained provider or specialist) Causing or spreading bacterial infection, pain, bleeding *As usual, should not be considered if performing this procedure will not change your management plan Sinus Puncture and Aspiration Palate approach Nasal approach http://www.theasthmacenter.org/index.php/disease_information/sinusitis/types_of_sinusitis/acute_sinusitis/causes_of_acute_sinusitis/viral_infections/ End of Content Slides Questions? Group Activity Up Next! Small Group Activity Please go on to Brightspace and open the “Week 2 Group Survey” Work in your randomly-assigned group through the two questions in the survey. Once you have your group answers, each student individually should respond to the survey to get credit. Example Patient One 19 y/o F College of Charleston student comes into your office for complaint of sore throat. Pt states this started 3-4 days ago, worse now. No fever/chills noted. Pt denies lymph node swelling in her neck/head area. Temp is 98 (37.1*C) at arrival, vital signs otherwise normal. Pt does report “annoying cough” and congestion during this time. Pt states she thinks her friend has strep, but didn’t have direct contact with her. Her exam does not show tonsillar exudates, but there is some mild erythema and post-nasal drip to her posterior oropharynx. No cervical or local-area lymphadenopathy (LAD). According to Centor Criteria, what should be done? Example Patient Two A 14 y/o M patient presents to urgent care with his mother. Pt is said to have a temp of 101 (38.4*C) at home and complaining of sore throat x 1 day. No cough, rhinorrhea, or ear pain reported. On exam patient has tonsillar exudates, tender cervical LAD, and erythematous posterior throat. Ear exam normal. No meningitis concern at this time, as neck ROM/flexion (etc) are normal. NOTES ( Friday 09/01) Scrotum abscess example CT first to see how bad Maybe do bed side ultrasound to see the direction Cyst: movable, non tender, stay for long time Pilonidal cysts??? Strep testing : strep, group A beta hemolytic strep (GAS)-à peritonsillar abscess Child à Good airwayà Thumb sign?? Strep