VT 121 Respiratory Powerpoint

VT121

Respiratory Diseases

Alveoli
N
Trachea
Bronchiole
Bronchus

Terminology - Abbreviations

  • TV - Tidal Volume
    • Definition: The volume of air inspired or expired during normal respiration.
  • ERV - Expiratory Reserve Volume
    • Definition: The maximum volume of air that can be expired after a normal expiration.
  • IRV - Inspiratory Reserve Volume
    • Definition: The maximum volume of air that can be inspired after a normal inspiration.
  • VC - Vital Capacity
    • Definition: The maximum amount of air that can be moved into or out of the lungs.
    • Formula: VC=TV+ERV+IRVVC = TV + ERV + IRV
  • RV - Residual Volume
    • Definition: Air remaining in the lungs after a forced expiration.
  • COPD - Chronic Obstructive Pulmonary Disease
    • Definition: Chronic inflammation and fibrosis of lung tissue that causes difficulty in inspiration and expiration.

Terminology – Word Components

  • Rhinorrhea
    • Breakdown: rhino = nose, rhea = flow or discharge.
  • Hemoptysis
    • Breakdown: hemo = blood, ptysis = spitting.
  • Tachypnea
    • Breakdown: tachy = abnormally fast, pnea = breathing.
  • Tracheostomy
    • Breakdown: tracheo = windpipe, ostomy = surgically creating an opening.
  • Pneumonia
    • Breakdown: pneumo = lung or air, -ia = state or condition.
  • Pulmonitis
    • Breakdown: pulmo = lung, itis = inflammation.
  • Antitussive
    • Breakdown: anti = against, tuss = cough, ive = performing a specified action.
  • Chylothorax
    • Breakdown: chylo = lymphatic fluid, thorax = chest cavity.
  • Bronchiectasis
    • Breakdown: bronchi = bronchial tube, ectasis = dilation or enlargement.

Terminology

  • Agonal Breathing
    • Definition: Respirations occurring near death or during extreme suffering.
  • Apnea
    • Definition: Absence of breathing.
  • Asphyxiation
    • Definition: Suffocation, to deprive of oxygen.
  • Asthma
    • Definition: Chronic allergic disorder characterized by airway inflammation and constriction.
  • Atelectasis
    • Definition: Incomplete expansion of the alveoli or collapse of the lung.
  • Crackles
    • Definition: Abnormal crackling noises heard on auscultation of the lungs caused by sudden opening of collapsed or fluid-filled small airways.
  • Dyspnea
    • Definition: Difficult or labored breathing.
  • Emphysema
    • Definition: Chronic lung disease caused by enlargement of the alveoli or changes in the alveolar walls.

Terminology (Continued)

  • Epistaxis
    • Definition: Nosebleed.
  • Hypercapnia
    • Definition: Excessive amounts of carbon dioxide in the blood.
  • Pleural Effusion
    • Definition: Abnormal accumulation of fluid in the pleural space.
  • Pneumothorax
    • Definition: Abnormal accumulation of air or gas in the chest cavity.
  • Stenosis
    • Definition: Narrowing or stricture of a passage or opening.
  • Stridor
    • Definition: Snoring, squeaking, or whistling sounds that suggest airway narrowing.
  • Tracheal Wash
    • Definition: Collection of fluid or mucus from the trachea via an endotracheal tube.
  • Wheezes
    • Definition: Abnormal whistling sounds heard on auscultation caused by air passing through narrowed airways.

Physical Exam Observations

  • Observe how the animal is breathing before touching them.
  • Note the respiratory rate and respiratory effort.
  • Check naris and nose for nasal discharge and swelling.
  • Check the mouth for ulcers and mucous membrane color.

Respiratory System Review

  • Heart and lungs are interlinked; observe the functioning relationship.

Physical Exam Auscultation

  • Imagine each side of the chest is divided into quadrants.
    • Listen carefully in each quadrant for abnormal sounds such as wheezes, crackles, or absent sounds.

Use Caution with Dyspneic Patients

  • Handle dyspneic patients with extreme care.
  • Recognize that stress can exacerbate respiratory diseases and can be fatal.
  • If a patient is struggling to breathe, place them in a quiet oxygen cage before handling.
  • Sedatives may be required in these situations.
  • Diagnostic procedures should be skipped until the patient is stable.

Diagnostics

Thoracic Radiographs

  • Perform right lateral and ventrodorsal (VD) views.
  • Radiographs should be taken on inspiration.
  • Collimate from the thoracic inlet to the second to last rib.
  • If the patient cannot tolerate VD positioning, a dorsoventral (DV) view can be used.
  • When checking for tracheal diseases, include the neck and collimate to the base of the skull.

Skull/Nasal Radiographs

  • Purpose: Used to examine the nasal turbinates or sinuses.
  • Sedation/anesthesia is typically required for high-quality images.
  • Standard views include lateral and DV/VD.
  • Extra views for nasal cavity include VD open mouth, frontal 90 rostral caudal, or intraoral DV.

CBC/Chemistry

  • White blood cell counts typically increase in infectious/inflammatory diseases.
  • Some respiratory diseases relate to other body systems.

Computerized Tomography (CT) Scan

  • Provides more detailed imaging than radiographs.
  • Patients must be sedated or under anesthesia to perform the CT scan.

Rhinoscopy

  • Requires heavy sedation or general anesthesia.
  • An otoscope and cone or rigid scope are used.
  • Pharyngeal exam performed under sedation.
  • Useful for diagnosing foreign bodies or conditions such as brachycephalic syndrome or laryngeal paralysis.

Bronchoalveolar Lavage (BAL)

  • Conducted during bronchoscopy.
  • Requires patients to be under anesthesia.
  • Sterile water is introduced into a lung segment and suctioned back for laboratory evaluation.

Thoracocentesis

  • Used to sample pleural effusion.
  • A needle is inserted into the chest to remove fluid for testing, which can also provide therapeutic relief, enabling better breathing for the patient.

Diseases Covered in this Lesson

  • Nasal tumors
  • Nasal polyps
  • Epistaxis
  • Sinusitis
  • Tonsillitis
  • Brachycephalic syndrome
  • Laryngitis
  • Laryngeal paralysis
  • Kennel cough
  • Collapsing trachea
  • Feline asthma
  • Pneumonia
  • Feline heartworm disease
  • Feline upper respiratory infections
  • Fungal disease
  • Pulmonary neoplasia
  • Pleural effusion

Nasal Tumors

  • Description: Aggressive locally but slow to metastasize.
  • Common types: Adenocarcinoma (dogs) or lymphoma (cats).
  • Clinical Signs:
    • Sneezing/snoring
    • Pawing at nose
    • Unilateral nasal discharge or bleeding
    • Facial deformity
    • Seizures
  • Diagnosis:
    • Imaging (radiographs, CT, or MRI) and rhinoscopy with biopsy.
  • Treatment:
    • Options include surgery, radiation, or chemotherapy depending on the tumor type.

Nasal Polyps

  • Definition: A polyp is a benign mass, commonly found in cats.
  • Growth Description: Grows from the middle ear into the back of the throat or nasal cavity.
  • Symptoms: Can cause partial obstruction resulting in snorting sounds while breathing.
    • Secondary bacterial infections may lead to nasal discharge and sneezing.
  • Treatment: Surgical removal is necessary. If the polyp root is not removed, reoccurrence frequently occurs.

Epistaxis

  • Definition: Bleeding from the nose.
  • Causes:
    • Trauma
    • Foreign bodies
    • Coagulopathies (e.g., warfarin or rat-bait)
    • Neoplasia (intranasal or multiple myeloma)
    • Fungal infections
  • Treatment:
    • Address the underlying cause.
    • Mild bleeding may require elevating the nose.
    • Severe bleeding may require packing the nose with a vasoconstrictive drug-soaked cotton tip applicators.

Sinusitis

  • Definition: Infection or inflammation of the sinus cavities.
  • In dogs, most often secondary to a tooth root abscess.
  • Clinical Signs:
    • Swelling under the eye on the affected side
    • Unilateral or bilateral nasal discharge
  • Treatment: Removal of the abscessed tooth and administration of antibiotics.

Tonsillitis

  • Definition: Inflammation of the tonsils which are lymphoid tissues in the throat.
  • Clinical Presentation: Tonsils swell up in response to infection.
  • Diagnosis: Made by visualization of swollen, infected tonsils.
  • Treatment: Involves antibiotics, pain control, and soft foods.

Brachycephalic Syndrome

  • Definition: A condition affecting certain breeds with anatomical airway abnormalities.
  • Breeds Affected: Pug, Bulldog, Boston Terrier, Pekingese, and Shih-Tzu.
  • Characterized by:
    • Stenotic nares
    • Elongated soft palate
    • Everted laryngeal saccules
    • Hypoplastic trachea
  • Treatment: Surgical correction can improve breathing issues.

Laryngitis

  • Description: Most commonly caused by excessive barking or meowing.
  • Other Causes: Upper respiratory tract infections causing loss of voice.
  • Treatment: Involves rest, antibiotics (if indicated), and anti-inflammatory medications.

Laryngeal Paralysis

  • Definition: Caused by weakness or paralysis of the nerve that innervates laryngeal muscles.
  • Causes: May include neuromuscular degeneration, trauma, or neoplasia.
  • Breeds Most Affected: Irish Setters and Labrador Retrievers.
  • Clinical Signs:
    • Exercise intolerance
    • Noisy breathing (stridor)
    • Cough
    • Voice change
    • Cyanosis or syncope
  • Diagnosis: Examining the larynx under heavy sedation with a laryngoscope or endoscope.
  • Treatment: Using sedatives, avoiding excitement or heat, and using a harness instead of a neck lead. Severe cases may require laryngeal tie-back surgery.

Infectious Tracheobronchitis (Kennel Cough)

  • Definition: A general term for an infectious cough spread through kennels, also known as infectious tracheobronchitis.
  • Symptoms: Loud "goose honk" cough, often with normal energy levels.
  • Clinical Testing: Palpation of the trachea stimulates a cough.
  • Possible Causative Agents:
    • Adenovirus
    • Parainfluenza virus
    • Canine Coronavirus
    • Bordetella bronchiseptica
  • Treatment: Varies from rest and isolation to antibiotics (e.g., doxycycline) and cough suppressants (e.g., Hycodan).

Collapsing Trachea

  • Description: The cartilage in the trachea becomes soft and floppy, leading to airway narrowing during inspiration.
  • Symptoms: Chronic, dry, harsh cough that worsens at night, with excitement, or with neck pressure.
  • Breeds Most Affected: Pomeranians, Yorkshire Terriers, Poodles, and Chihuahuas.
  • Treatment: Avoiding neck leads, cough suppressants, weight control, and anti-inflammatory medications. Some cases may require stenting procedures by specialists.

Feline Asthma

  • Definition: A condition resulting from inflammation of the airways due to various triggers.
  • Triggers: Could include dust, smoke, mold, aerosols, pollen, dust mites, and certain foods.
  • Symptoms: Dry cough with gagging, presenting later as dyspnea and wheezing.
  • Diagnosis: Based on physical exam, bloodwork, and radiographs.
  • Treatment: May include steroids and bronchodilators, commonly administered via inhalers.

Pneumonia

  • Definition: Infection or inflammation of the lungs and bronchi, commonly caused by viral, bacterial, fungal, or parasitic pathogens or aspiration.
  • Diagnosis: Typically via thoracic radiographs.
  • Treatment: Involves antimicrobials, oxygen support, IV fluids, nebulization, and coupage depending on severity.

Feline Heartworm Disease

  • Transmission: Spread via mosquito bites; 6 months required for microfilariae to mature into adults.
  • Clinical Signs: Respiratory symptoms in cats, such as cough and dyspnea.
  • Diagnosis: Antigen or antibody blood tests, radiographs may show distended pulmonary arteries, and ultrasound may display worms.
  • Preventative Measures: Cats in heartworm-endemic areas should receive heartworm preventative treatments.

Feline Upper Respiratory Infection (URI)

  • Description: Similar to a "cold" in humans.
  • Clinical Signs: Sneezing, congestion, runny nose, cough, decreased appetite, and conjunctivitis.
  • Transmission: Via aerosolization, direct contact, or fomites.
  • Diagnosis: Typically based on clinical signs but can be confirmed via respiratory PCR panels utilizing nasal, conjunctival, and pharyngeal swabs.
  • Treatment: Supportive care, with antibiotics and antivirals when necessary; steroids and stress should be avoided.

Feline Upper Respiratory Infection (URI) Pathogens

  • Feline Herpesvirus: Most common cause; vaccination through FVRCP vaccine.
  • Feline Calicivirus: Causes oral ulcers; also vaccinated against via FVRCP.
  • Feline Chlamydia: Involves conjunctivitis.
  • Feline Bordetella: Associated with stress and overcrowded conditions.
  • Cryptococcus: Fungal infection acquired from bird droppings and decaying plants.

Fungal Diseases

  • Geographical Variance: Fungal infections vary across the United States and are more common in dogs than cats.
  • Areas Affected: Can affect the nose, sinuses, lungs, or multiple locations.
  • Clinical Signs: Chronic cough, acute respiratory distress, lethargy, facial swelling, or nasal discharge.
  • Diagnosis: Bloodwork, radiographs, serology, urine antigen tests, cytology, or PCR tests.
  • Treatment: Involves systemic antifungals, oxygen therapy, and possible anti-inflammatory medications.

Fungal Diseases - Common Infections

  • Blastomycosis: Found in warm humid areas of the Southeast.
  • Coccidioidomycosis: Known as “Valley Fever,” typically occurs in the Southwest.
  • Histoplasmosis: Common in soil containing bird or bat feces around the Mississippi, Missouri, and Ohio River Valleys.
  • Cryptococcosis: Worldwide distribution, mainly infects cats, and is concentrated in bird droppings.
  • Aspergillosis: Found globally on decaying vegetation, affects various species, including birds.

Pulmonary Neoplasia

  • Adenocarcinomas: The most common type of primary lung cancer in dogs and cats.
  • Metastatic Tumors: More frequently affecting dogs and cats, requiring comprehensive evaluation.
  • Diagnosis: Conduct three view chest radiographs, often referred to as a "met check," involving left lateral, right lateral, and ventrodorsal views; fine needle aspiration through the chest wall.
  • Treatment: Primary lung cancer may be surgically removed; metastatic disease usually has a poor prognosis, requiring chemotherapy or radiation.

Pleural Effusion

  • Definition: The pleural space is the area around the lungs in the thorax, with pleural effusion filling this area and preventing full lung expansion.
  • Symptoms: Patients take rapid, shallow breaths with muffled lung sounds.
  • Diagnostics: Thoracocentesis is employed to collect fluid samples or drain excess fluid for patient comfort.
  • Additional Treatments: May include heart medications, antibiotics, or vitamin K.

Pleural Effusion - Types

  • Congestive Heart Failure: Fluid is typically clear/straw colored.
  • Chylothorax: Caused by lymphatic ducts leaking white/pink fluid, may be secondary to trauma, heart disease, neoplasia, or idiopathic causes.
  • Pyothorax: Characterized by pus and infection in the chest cavity, treated with antibiotics and possible chest tube placement.
  • Hemothorax: Accumulation of blood, with causes being trauma or coagulopathy (e.g., rat bait toxicity).

Therapeutics

  • Antimicrobials: General category of drugs targeting specific infections.
    • Examples:
    • Antibiotics: Doxycycline, Clavamox, Clindamycin, Azithromycin, Enrofloxacin.
    • Antifungals: Ketoconazole, Fluconazole, Itraconazole, Terbinafine, Amphotericin.
    • Antivirals: Famciclovir, interferon, lysine.
    • Warnings: Ensure clients hydrate when administering doxycycline to prevent esophageal stricture from improper swallowing.

Therapeutics - Continuing

  • Anti-Inflammatories: Steroids such as prednisone, dexamethasone, or inhaled fluticasone.
  • Bronchodilators: Theophylline, aminophylline, albuterol (delivered via inhalant).
  • Cough Suppressants: Hycodan (controlled substance), guaifenesin.
  • Diuretics: furosemide, torsemide, spironolactone.
  • Antihistamines: diphenhydramine (Benadryl).