Mohammed El-Khateeb MSVL-4 Nov 26 th 2013

Transcription

1 Mohammed El-Khateeb MSVL-4 Nov 26 th 2013

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3 The respiratory system is the most commonly infected system. Health care providers will see more respiratory infections than any other type.

4 Geography of the respiratory system (and sites of infection)

5 A major portal of entry for infectious organisms The upper respiratory tract: Mouth, nose, epiglottis, Nasal cavity, sinuses, pharynx, and larynx Infections are fairly common. Usually nothing more than an irritation The lower respiratory tract: Lungs and bronchi Infections are more dangerous. Can be very difficult to treat

6 The most accessible system in the body, continuously exposed to potential pathogens. Breathing brings in clouds of potentially infectious pathogens. The body has a variety of host defense mechanisms. Innate immune response The cells and mechanisms that defend the host from infection by other organisms, in a nonspecific manner Adaptive immune It is adaptive immunity because the body's immune system prepares itself for future challenges.

7 Protective structures of the respiratory system Ventilatory flow Involuntary responses such as coughing, sneezing and swallowing Mucous membranes Hairs; ciliated epithelia Lymphoid tissues (tonsils) Mucociliary escalator keeps microbes out of lower respiratory tract Alveolar macrophages; IgA

8 Normal Flora: Moraxella, nonhemolytic and a-strep, Coryenbacterium, Diphtheroids, Candida albicans, Others

9 Definition: Sore Throate Inflammation of the mucous membranes and submucosal structures of the oropharynx but not tonsils

10 30%-65%: idiopathic 30%-60%: viral 5%-10%: bacterial Group A beta-hemolytic: most common bacterial pathogen 15%-36%: pediatric cases 5%-10% : adult pharyngitis Disease of children

11 Strep.A Mycoplasma Strep.G Strep.C Corynebacterium diphteriae Toxoplasmosis Gonorrhea Tularemia Rhinovirus Coronavirus Adenovirus CMV EBV HSV Enterovirus HIV

12 Pharyngeal mucosa exhibits an inflammatory response to many other agents other than viruses Opportunistic bacteria Fungi Environmental pollutants Neoplasm Granulomatous disease Chemical and physical irritants

13 Sore throat is estimated to account for 10% of all general practice consultations Asymptomatic carriage of streptococcus Is common with rates of 6-40% Carriers have low infectivity and are not at risk of developing complications such as rheumatic fever

14 Inflammation of the throat Pain and swelling, reddened mucosa, swollen tonsils, sometime white packets of inflammatory products Mucous membranes may swell, affecting speech and swallowing Often results in foul-smelling breath Incubation period: 2-5 days

15 Sore throat Pain on swallowing Fever Hoarseness if laryngeal involvement Gradual onset Rhinorrhea Cough Diarrhea Headache Malaise

16 Redness of the pharynx and tonsils Presence of exudate Enlarged tonsils Swollen tender neck glands. Note that a streptococcal sore throat is impossible to diagnose on clinical grounds alone.

17 Full head and neck exam General respiratory distress, toxic Face mouth breathing Nose rhinorrhea Neck lymph nodes, thyroid, Mucosal edema, tonsillar swelling, exudates, discrete lesions, deviation of the uvula or tonsillar pillars, bulges in the posterior pharyngeal wall Laryngoscopy Nasal endoscopy - sinusitis

18 Treatment VIRAL Supportive care only Analgesics, Antipyretics, Fluids No strong evidence supporting use of oral or intramuscular corticosteroids for pain relief few studies show transient relief within first hrs after administration EBV infectious mononucleosis activity restrictions mortality in these pts most commonly associated with abdominal trauma and splenic rupture

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20 Commonly called a sinus infection Most commonly caused by allergy Can also be caused by infections or structural problems Generally follows a bout with the common cold Symptoms: nasal congestion, pressure above the nose or in the forehead, feeling of headache or toothache Facial swelling and tenderness common Discharge appears opaque with a green or yellow color in case of bacterial infection Discharge caused by allergy is clear and may be accompanied by itchy, watery eyes

21 Also a common sequel of rhinitis Viral infections of the upper respiratory tract lead to inflammation of the Eustachian tubes and buildup of fluid in the middle ear- can lead to bacterial multiplication in the fluids Bacteria can migrate along the eustachian tube from the upper respiratory tract, multiply rapidly, leads to pu production and continued fluid secretion (effusion) Chronic otitis media: when fluid remains in the middle ear for indefinite periods of time (may be caused by biofilm bacteria) Symptoms: sensation of fullness or pain in the ear, loss of hearing Untreated or severe infections can lead to eardrum rupture

22 Figure 21.2

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24 Most common agents in pharyngitis are the rhinovirus and coronavirus Both single stranded, + sense RNA picornaviruses Grow best at 33 degrees Celsius Approximates the temperature of the nasopharynx Disease is self-limited Clinical signs and symptoms may be identical to bacterial pharyngitis Evaluation for Group A streptococcus is advisable

25 Major cause of acute respiratory disease Rhinovirus &Coronaviruses Respiratory syncicial virus Parainfluenza viruses Respiratory syncicial virus Herpes Group HIV

26 RHINOVIRUS INFECTION -There are several hundred serotypes of rhinovirus. Fewer than half have been characterized. 50% that have are all picornaviruses. Extremely small, non-enveloped, singlestranded RNA viruses Optimum temperature for picornavirus growth is 33 C. The temperature in the nasopharynx

27 PARAINFLUENZA: There are four types of parainfluenza virus. All belong to the paramyxovirus group. Single-stranded enveloped RNA viruses Contain hemagglutinin and neuraminidase Transmission and pathology similar to influenza virus, but there are differences. Parainfluenza virus replicates in the cytoplasm. Influenza virus replicates in the nucleus.

28 Parainfluenza is genetically more stable than influenza. Very little mutation Little antigenic drift No antigenic shift Parainfluenza is a serious problem in infants and small children. Only a transitory immunity to reinfection Infection becomes milder as the child ages.

29 Produces giant multinucleated cells (synctia) in the respiratory tract Most prevalent cause of respiratory infection in the newborn age group First symptoms: fever that lasts approximately 3 days, rhinitis, pharyngitis, and otitis More serious infections give rise to symptoms of croup: coughing, wheezing, dyspnea, rales

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31 Etiologic agent of infectious mononucleosis (IM) Herpes virus 4 Double stranded DNA virus Selectively infects B-lymphocytes

32 Early infections in life are mostly asymptomatic Clinical disease is seen in those with delayed exposure (young adults) Defined by clinical triad Fever, lymphadenopathy, and pharyngitis combined with +heterophil antibodies and atypical lymphocytes

33 Other clinical findings Splenomegaly 50% Hepatomegaly 10% Rash 5%

34 Pharyngitis White membrane covering one or both tonsils Petechial rash involving oral and palatal mucosa

35 Diagnosis By Clinical presentation CBC with differential (atypical lymphocytes T lymphocytes) Detection of heterophil antibodies (Monospot test) IgM titers

36 Supportive management Rest Avoidance of contact sports (?- >splenic rupture?) Glucocorticoids (severe cases)

37 Complications Autoimmune hemolytic anemia Cranial nerve palsies Encephalitis Hepatitis Pericarditis Airway obstruction

38 Herpes virus 5 Ubiquitous 50% of adults seropositive 10-15% of children seropositive by age 5 years Etiology of 2/3 of heterophil-negative mononucleosis

39 Clinical manifestation Fever and malaise Pharyngitis and lymphadenopathy less common Esophagitis in HIV infected patients

40 Diagnosis 4-fold rise in antibody titers to CMV

41 Herpes (Greek word herpein, to creep ) Two antigenic types (HSV-1, HSV- 2) Both infect the upper aerodigestive tract Transmission is by direct contact with mucous or saliva

42 Clinical manifestations Depends on Anatomic site Age Immune status of the host First episode (primary infection) More systemic signs and symptoms Both mucosal and extramucosal sites involved Longer duration of symptoms

43 Clinical manifestations: Gingivostomatitis and pharyngitis most common in first episode Usually in children and young adults Fever, malaise, myalgias, anorexia, irritability

44 Physical exam Cervical lymphadenopathy Pharynx exudative ulcerative lesions Grouped or single vesicles on an erythematous base Buccal mucosa Hard and soft palate

45 Clinical manifestations Acute illness evolves over 7-10 days Rapid regression of symptoms Resolution of lesions

46 Immunocompromised patient Persistent ulcerative lesions are common in patients with AIDS Lesions more friable and painful Aggressive treatment with IV acyclovir

47 Diagnosis Usually clinical Isolation of HSV Culture from scrapings of lesions oresults in 48 hours

48 Treatment Acyclovir, 400 mg PO 5X/day X 10days Valacyclovir, 1000 mg PO BID X 10 days Recurrent disease Acyclovir 400 mg PO 5X/day for 5 days Duration reduced from 12.5 to 8.1 days Acyclovir 400 mg po bid every day Recurrence reduced 36% to 19%

49 Pharyngitis Usually opportunistic infection HSV CMV Candida Viral particles have been detected in lymphoepithelial tissues of the pharynx