3rd March.2015.Physiology module
Dr Jalees Khalid Khan
Pathology Deptt. KEMU. Lahore
Upper respiratory tract
infections are the most
common human affliction.
Major share of time lost
from work and school.
Most common cause of
antibiotic abuse.
Figure 21.1
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•
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Generally limited to the upper respiratory tract
Gram-positive bacteria (streptococci and
staphylococci) very common
Disease-causing bacteria are present as normal
biota; can cause disease if their host becomes
immunocompromised or if they are transferred
to other hosts (Streptococcus pyogenes,
Haemophilus influenza, Streptococcus
pneumonia, Neisseria meningitides,
Staphylococcus aureus)
•
Normal biota perform microbial antagonism
•
•
•
•
Most common place for infectious agents to gain
access to the body
Upper respiratory tract: mouth, nose, nasal
cavity, sinuses, pharynx, epiglottis, larynx
Lower respiratory tract: trachea, bronchi,
bronchioles, lungs, alveoli
Defences
Nasal hair
Cilia
Mucus
Involuntary responses such as coughing, sneezing, and
swallowing
– Macrophages
– Secretory IgA against specific pathogens
–
–
–
–
 Influenza
 Epiglottitis
 Sinusitis
 The
Common Cold
 Diphtheria





Nosocomial infections-indisciminate use of drugs
by doctors and quacks.
Drug resistance-causes
Cell wall alteration, Plasmid, ESBL,Efflux pump
etc
Lysogenic strains
MRSA and others





Pandemics
Epidemics
Endemic
Seasonal
Age
Worldwide - antigenic
shift
Local - antigenic drift
Sporadic
Winter months - abrupt
Infection: children
>adults
Mortality: adults
>children

Virus replication: 24 - 72 hours

Virus excretion: 3 - 7 days

Antibodies to HA, NA subtypes

S. pneumoniae

H. influenzae

S. aureus - Toxin Shock Syndrome





Post influenza B
Encephalopathy
Hepatic dysfunction
Elevate NH3, LFTs, CPK
Children:Streptococcus pneumoniae
◦ Most common cause outside of neonatal period
◦ Nasopharyngeal colonization – 50% of kids
◦ >90 serotypes – majority of invasive disease caused by
10 serotypes
◦ Bacteremia in 25-30% of kids
◦ Gram stain – gram positive lancet shaped diplococci
(“gram positive cocci in pairs”)

Adults – lobar pneumonia

Kids – lobar or bronchopneumonia


Classically a lobar consolidation on CXR
Raise suspicion of staph
◦
◦
◦
◦
Pneumatoceles
Pleural effusion
Air fluid levels
Necrosis



Changes in alveolar epithelial-ciliated columnar to
pseudostratified/columnar epithelium
Inefficiency of cilia to expel the
debris,contaminants,carbon etc inhaled from
atmosphere
Emphysema, COPD, Bronchiectasis,Carcinoma of
lung
Trivalent vaccine
A/Beijing/262/95-like
(H1N1)
A/Sydney/5/97-like
(H3N2)
B/Harbin/07/94





Elderly (age>65)
High-risk*
Household contacts
Health-care personnel
Pregnant women after 14th week
High-risk: institutionalized, chronic heart or
lung disease, diabetes,
renal dysfunction, immunosuppressed,
children on aspirin




Killed vaccines
Live vaccines
Live vaccines are long acting while short acting are
killed vaccines
Immunization
◦ Measles –
 Pneumonia is what they die of – often super-infection
 World-wide coverage rate – 76% in 2004
 Still having 30-40 million cases a year
◦ HemophilusInfluenzae B –




2-3 million cases of severe disease a year
In 2003, developed world coverage – 92%
Developing world – 42%
Least developed countries – 8%
Timing: October Mid-November
Duration of immunity:
start 1-2 weeks
end 4-6 months
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Prozone phenomenon
Serum sickness
Fever, lymphadenopathy
Severe anaphylactic reation
Defective vaccine production-NIH
DPT-not properly killed
*Viral culture – tissue
culture
*Fluorescent-labeled
murine monoclonal Ab shell viral cell culture viral Ag
*PCR
*CF - at onset and 2 weeks
4-fold-rise in Ab titre
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
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Control of outbreaks in institutions
Adjunct to late vaccination
Immunodeficient - AIDS
Vaccine contraindicated
Home caregivers of high risk

Epidemiology:
◦ most common in children 3-7 yrs.
◦ decreased incidence because of Hib conjugate
vaccine-stable rate in adults

Rate:
◦ 1 in 1000-2000 pediatric admissions
◦ 1 in 100,000 adult admissions

Peritonsillar abscess
◦ sore throat, drooling, hoarseness, trismus, asymmetric
tonsillar enlargement

Epiglottitis
◦ Children: high fever, toxic, drooling, absence of cough
◦ Adult: severe sore throat, dyshagia, fever

Infectious mononucleosis
◦ tonsillar enlargement, exudative tonsillitis, pharyngeal
inflammation, lymphadenopathy, splenomegaly,
maculopapular rashes, petechial anathema

Parapharyngeal space infection
◦ neck swelling after a sore throat



Haemophilus influenzae type b,
S. pneumoniae, S. aureus, H. influenzae type
non-b, H. parainfluenzae
Inflammation and edema of the epiglottis,
arytenoids, arytenoepiglottic folds, subglottic
area
Epiglottis pulled down into larynx and
occludes the airway
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Visualization of epiglottis - “cherry red”
Laternal neck x-rays: “thumb sign”
WBC count > 15,000 left shift
Blood cultures
Prophylaxis: Rifampin - 20 mg/kg for 4 days
All household contacts if children under 4
Daycare and nursery school contacts
Patient before discharge
*Viral URI, fever (50%),
purulent nasal discharge,
swelling, facial pain worse on
percussion, headache, nasal
obstruction, loss of smell
*Children: facial pain,
swelling, malodorous breath
(50%), cough (80%), nasal
discharge (76%), fever (63%),
sore throat (23%)
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



Nasal swabs not helpful
Transillumination of maxillary and frontal
sinuses
Sinus x-rays: air-fluid level, complete
opacity, mucosal thickening
CT scan not indicated - unless chronic
infection, immunocompromised, suspected
intracranial or orbital complication
Direct sinus aspiration
 Impaired
mucociliary function
 Obstruction of sinus ostia
 Immune defects
 Increased risk of microbial
invasion
Children
MICROBIAL AGENT (Bacteria)
Streptococcus pneumoniae
Haemophilus influenzae
(nonencapsulated)
S. pneumoniae and H. influenzae
Anaerobes (Bacteroides, Fusobacterium,
Peptostreptococcus, Veillonella)
Staphylococcus aureus
Streptococcus pyogenes
Branhamella (Moraxella) catarrhalis
Gram-negative bacteria
 Fugal causes in immunocompromised
PREVALENCE MEAN (RANGE)
Adults
(%)
31 (20-35)
21 (6-26)
5 (1-9)
6 (0-10)
(%)
36
23
---
4 (0-8)
2 (1-3)
2
9 (0-24)
-2
19
2
PREVALENCE MEAN (RANGE)
Adults
Children
(%)
(%)
MICROBIAL AGENT
Viruses
Rhinovirus
15
Influenza virus
5
Parainfluenza virus 3
Adenovirus
--2
--
2
Complication

Meningitis

Osteomyelitis
Epidural abscess
Subdural empyema

Cerebral abscess



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Venous sinus thrombosis
death
Cavernous sinus
palsies
Clinical Signs
Headache, fever, stiff neck
lethargy, rapid
death
Pott’s puffy tumor
Headache, fever
Headache, seizures
hemiplegia, rapid death
Convulsions, headache,
personality change
Picket-fence fever, rapid
Orbital edema, ocular
Virus type
Andenoviruses
Coronaviruses
Influenza viruses
Parainfluenza viruses
Respiratory syncytial virus
Rhinoviruses
Enteroviruses
Serotypes
41
2
3
4
1
100+
60+


May-Aug
Sept-Dec
Rhinoviruses,

Jan-Feb -

Mar-Apr
Enteroviruses
Mycoplasma,
Parainf. 1+2, RSV
Adenoviruses, Influenza,
Coronaviruses
Parainf. 3, Rhinoviruses
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Direct contact with infected secretions
Hand - to - hand
Hand - to environmental surface - to hand
Spread by aerosoles
Complications:Bacterial superinfection
◦ Otitis media
◦ Sinusitis
◦ S. pneumoniae, H. influenzae, B. catarrhalis


Guillain-Barre Syndrome
Asthma attacks



Aspirin - prolonged excretion of rhinoviruses,
influenza virus
Children - aspirin associated with Reye’s
syndrome
Prevention:Vaccines
◦ influenza A/B
◦ adenoviruses types 4,7

Intranasal interferon
◦ rhinoviruses
◦ nasal obstruction, bloody discharge