Respiratory Tract Infections Ch 2 PDF

CHAPTER 30: RESPIRATORY TRACT INFECTIONS, NEOPLASMS, AND CHILDHOOD DISORDERS A R E A S I N V O LV E D I N R E S P I R AT O RY T R A C T INFECTIONS Upper respiratory tract Nose, oropharynx, and larynx Lower respiratory tract Trachea, bronchi...

CHAPTER 30: RESPIRATORY TRACT INFECTIONS, NEOPLASMS, AND CHILDHOOD DISORDERS A R E A S I N V O LV E D I N R E S P I R AT O RY T R A C T INFECTIONS Upper respiratory tract Nose, oropharynx, and larynx Lower respiratory tract Trachea, bronchi and lungs 2  COMMON R E S P I R AT O RY INFECTIONS Common cold Rhinosinusitis Influenza Pneumonia Tuberculosis Fungal infections of the lung Viruses are the most frequent cause of respiratory tract infections (Upper respiratory 3 infections—URI) Viral Etiology Pathogenesis Clinical Manifestations Diagnosis/ Treatment Commo Rhinoviruse Can spread Dryness/ Diagnosed n Cold s—most rapidly stuffiness of clinically common Children: nasopharynx Self-limiting Parainfluenza; major Clear watery Antipyretics respiratory reservoir nasal Symptom syncytial virus Fingers for secretion/tearin relief (RSV); human spread & g No need for metapneumo Nose/conjun Edematous and antibiotics virus (hMPV); ctiva as a erythematous coronavirus; portal mucous adenovirus Incubation: membranes Children: ~2 days Post nasal drip Bocavirus Duration: ~7 (PND) days Sore throat/hoarsen 4 ess TYPES OF SINUSES Paranasal sinuses: Air cells connected by narrow openings or ostia with the superior, middle, and inferior nasal turbinates of the nasal cavity Maxillary sinus Inferior to the bony orbit and superior to the hard palate Its opening is located superiomedially in the sinus, a location that impedes drainage. Frontal sinuses Open into the middle meatus of the nasal cavity Sphenoid sinus Anterior to the pituitary fossa behind the posterior ethmoid sinuses Its paired openings drain into the sphenoethmoidal recess at the top of the nasal cavity. Ethmoid sinuses Comprise 3 to 15 air cells on each side, 5with each maintaining a separate path to the nasal chamber Viral Etiology Pathogenesis Clinical Manifestations Diagnosis/ Treatment Rhino- Acute: viral, Most common: Hard to Diagnosed sinusitis bacterial or mixed With a viral URI differentiate from clinically Haemophilus or allergic common cold or Sinus influenza or rhinitis (causes allergic rhinitis radiographs/CT Streptococcus mucosal swelling Fever, facial pain, may be used pneumoniae & obstruction) headache purulent Viral: Nasal polyps nasal discharge, supportive care Chronic: bacterial Acute viral: ~ 5- decreased sense of Bacterial: or fungal 7 days without smell antibiotics Streptococcus/ treatment Maxillary: recent Mucolytics Staphaureus Acute bacterial: URI, nasal drainage, Decongestants or symptoms that pain with bending, Nasal irrigation Pseudomonas worsen after 5-7 unilateral maxillary aeruginosa days or persist pain, tooth pain beyond 10 days, or out of proportion May last up to 4 weeks 6 RHINOSINUSITIS Special Notes: Immunocompromised people (leukemia, aplastic anemia, HIV, bone marrow transplant) often present with FUO, rhinorrhea or facial edema, typically purulent drainage is absent Complications: Because of the sinuses’ proximity to the brain and orbital wall, sinusitis can lead to intracranial and orbital wall complications Intracranial complications: seen commonly with infection of the frontal/ ethmoid sinuses (proximity to the dura and drainage of the veins from the frontal sinus into the dural sinus) Orbital complications: range from edema of the eyelids orbital cellulitis subperiosteal abscess formation. Facial swelling over the involved sinus, abnormal extraocular movements, protrusion of the eyeball, periorbital edema, or changes in mental status may indicate intracranial complications and require TYPES OF I N F LU E N Z A VIRUSES Type A Most common type Can infect multiple species Causes the most severe disease Further divided into subtypes based on two surface antigens: hemagglutinin (H) and neuraminidase (N) Type B Has not been categorized into subtypes Type C Influenza B and C undergo less frequent antigenic shifts than influenza A, probably because few related viruses exist in mammalian or avian 8 species Viral Etiology Pathogenesis Clinical Diagnosis/Treatment Manifestations Influenza Orthomyxoviri Can cause three types of Abrupt onset of Rapid influenza dae family infections: fever, chills, rigors testing Uncomplicated URI Influenza A: (rhinotracheitis) Malaise, muscle Rest Can affect Viral pneumonia aches multiple species Respiratory viral infection Antipyretics (avian and followed by a bacterial Headache mammalian) infection Symptom relief Profuse, watery nasal Influenza B Transmission by inhalation discharge Antivirals in some of droplets populations (initiated Influenza C Nonproductive cough within 48 hours of Young children: common onset of symptoms) vectors and recipients Sore throat Amantadine (Symmetrel) (Flu A) Rapid Onset: can be as In severe cases: Rimantadine quick as 1-2 minutes— hypoxemia and (Flumadine) (Flu A) profound malaise death Zanamivir (Relenza) *Survivors often (Flu A & B) Incubation: 1-4 days (~2 develop pulmonary Oseltamivir days) fibrosis (Tamiflu) (Flu A & B) Infectious Period: Day 1- Day 7; (viral shedding can No need for continue x 3 weeks) antibiotics Peaks: ~3-5 days 9 Duration: ~7-10 days INFLUENZA Influenza vaccine Recommended from 6 months- on Complications: Sinusitis Otitis media Bronchitis Croup (children) Bacterial pneumonia Phenomenon of resolution of symptoms with return of fever, shaking chills, pleuritic chest pain, productive cough Most common: S. pneumoniae, S. aureus, H. influenzae, and Moraxella catarrhalis Reyes syndrome Rare condition that causes brain and liver damage (fatty liver with INFLUENZA : AVIAN (BIRD FLU) Avian influenza, or zoonotic influenza Caused by avian influenza viruses (occurs naturally among birds) Normal hosts: birds and occasionally pigs Avian strains usually do not cause outbreaks of disease in humans Can occur if a reassortment of the virus genome has occurred within an intermediate mammalian host (such as a pig) Virus is produced that contains mammalian characteristics as well as avian characteristics to which humans may not be immune Harmful subtypes: H5, H7, and H9 S/S: Typical influenza symptoms +eye infections, pneumonia, acute RDS INFLUENZA : SWINE FLU (H1N1) Caused by an influenza A flu known as the swine-origin influenza A flu (H1N1) Extremely high fevers Seriously affected young adults