For medical students

1. PNEUMONIA
Dr. Usman Shams

2. Classifications of PNEUMONIAS
• COMMUNITY ACQUIRED ACUTE
• HEALTH CARE-ASSOCIATED
• HOSPITAL ACQUIRED
• ASPIRATION
• CHRONIC
• NECROTIZING/ABSCESS FORMATION
• PNEUMONIAS in IMMUNOCOMPROMISED HOSTS

3. Although pneumonia is one
of the most common causes
of death, it usually does
NOT occur in healthy people
spontaneously

4. MORPHOLOGY
• LOBAR vs. BRONCHO
• “HEPATIZATION”, RED vs. GREY
• CONSOLIDATION
• “INFILTRATE”, XRAY vs. HISTOPATH
• Loss of “CREPITANCE”

10. COMMUNITY ACQUIRED, Bacterial
• STREPTOCOCCUS PNEUMONIAE
• HAEMOPHILUS INFLUENZAE (“H-Flu”)
• MORAXELLA
• STAPHYLOCOCCUS (STAPH)
• KLEBSIELLA PNEUMONIAE
• PSEUDOMONAS AERUGINOSA
• LEGIONELLA PNEUMOPHILIA
• MYCOPLASMA

11. STREPTOCOCCUS
• The classic LOBAR pneumonia
• Normal flora in 20% of adults
• Only 20% of victims have + blood cultures
• “Penicillins” are often 100% curative
• Vaccines are often 100% preventive

13. HAEMOPHILUS PNEUMONIA
• Commonest in CHILDREN <2, with otitis, URI,
meningitis, cellulitis, osteomyelitis, conjunctivitis
(pink eyes)
• PNEUMONIAS in CHILDREN <2 are often thought
of as being H Flu until proven otherwise.
• Most common pneumonia from COPD in adults
• BACTRIM (Trimethoprim-Sulfa) most common
treatment
• Vaccine available against capsulated form.

15. MORAXELLA CATARRHALIS
• 2nd most common COPD pneumonia, after
haemophilus
• Gram NEGATIVE coccobacillus, like H. Flu

16. STAPH aureus
• Most common pneumonia following viral
pneumonias
• M.R.S.A., of course, is usually NOT
“community” acquired
• IV Drug abusers
• Increased risk of complications … lung
abscess, empyema.

17. KLEBSIELLA PNEUMONIAE
• DEBILITATED MALNOURISHED PEOPLE
• ALCOHOLICS with pneumonia are often
thought of as having Klebsiella until proven
otherwise
• Thick, gelatinous, blood tinged sputum

18. PSEUDOMONAS Aeruginosa
• Usually NOT community acquired but
nosocomial
• Burns & Neutropenia
• CYSTIC FIBROSIS patients with pneumonia
are presumed to have PSEUDOMONAS until
proven otherwise
• Dangerous … invasive organism

19. LEGIONELLA (pneumophila)
• Often in OUTBREAKS
• Often LOBAR
• Spread by water “droplets”
• Often immunosuppressed patients …
TRANSPLANT

20. MYCOPLASMA
• Often in closed communities … SCHOOLS,
MILITARY CAMPS, PRISONS

21. COMMUNITY ACQUIRED, Viral
• CULTURES NOT HELPFUL
• Usually
– Confined to alveolar septum and
pulmonary interstitium
– Moderate amount of sputum
– No consolidation

22. VIRAL PNEUMONIAS
• Frequently “interstitial”, NOT alveolar

24. • INFLUENZA VIRUS
• RESPIRATORY SYNCITIAL VIRUS
• HUMAN METAPNEUMO VIRUS
• ADENOVIRUS
• RHINOVIRUS
• RUBEOLA
• VARICELLA

25. INFLUENZA VIRUS
• RNA virus … types A,B,C
• PAN-demics, type A
• Virulence factors:
– Hemagglutinin (H1-H3) … Attachment
– Neuroaminidase (N1, N2) … Release of newly formed
virions
• Antigenic drift … Has MUTATED throughout
history, many STRAINS … Avian (H5N1)
• B and C in children
• Exact strains can be ID’s by PCR

26. METAPNEUMO VIRUS
• Most commonly seen in extremes of ages and
immunocompromised
• 20% of paediatric outpatient URTIs

27. SARS
(Severe Acute Respiratry Syndrome)
• A new CORONA-VIRUS
• 2002 China outbreak
• Spread CHIEFLY in Asia
• Last infection … 2004 in lab.
• Like most viral pneumonias, interstitium
infiltrated, some giant cells often present

28. S
A
R
S

29. MORPHOLOGY
• Mucosal hyperemia and swelling,
lymphomonocytic and plasmacytic infiltration of
the submucosa
• Overproduction of mucus secretions.
• Plugging … suppurative secondary bacterial
infection.
• Tonsillitis … frequent in children
• Severe bronchiolar involvement …, organization
and fibrosis, resulting in obliterative bronchiolitis
and permanent lung damage.

30. HOSPITAL CARE-ASSOCIATED
• Recently described clinical entity
• Risk factors
– Hospitalization of at least 2 days within the recent
past
– Presentation from a nursing home or long-term care
facility
– Attending a hospital or hemodialysis clinic
– Recent intravenous antibiotic therapy, chemotherapy
or wound care. The most common
• Common organisms
– Methicillin-resistant Staphylococcus aureus
– P. aeruginosa.
• Higher mortality than those with community-
acquired pneumonia.

31. NOSOCOMIAL
• “Pulmonary infections acquired in the course of a
hospital stay.”
• Risk factors
– Severe underlying disease
– Immunosuppression
– Prolonged antibiotic therapy, or invasive access devices
such as intravascular catheters.
– Patients on mechanical ventilation
• Often life-threatening complications.
• Gram-positive cocci (mainly S. aureus and S.
pneumonia) and gram-negative rods
(Enterobacteriaceae and Pseudomonas species).

32. Classifications of PNEUMONIAS
• COMMUNITY ACQUIRED ACUTE
• HEALTH CARE-ASSOCIATED
• HOSPITAL ACQUIRED
• ASPIRATION
• CHRONIC
• NECROTIZING/ABSCESS FORMATION
• PNEUMONIAS in IMMUNOCOMPROMISED HOSTS

33. ASPIRATION PNEUMONIAS
• UNCONSCIOUS PATIENTS
• PATIENTS IN PROLONGED BEDREST
• LACK OF ABILITY TO SWALLOW OR GAG
• USUALLY CAUSED BY ASPIRATION OF GASTRIC
CONTENTS
• POSTERIOR LOBES (gravity dependent) MOST
COMMONLY INVOLVED, ESPECIALLY THE SUPERIOR
SEGMENTS OF THE LOWER LOBES
• TYPICALLY MORE THAN ONE ORGANISM IS FOUND ON
CULTURES.
• OFTEN LEAD TO ABSCESSES

34. • MICROASPIRATION
– GERD patients
– Leads to small, poorly formed non-necrotizing
granulomas with multinucleated foreign body
giant cell reaction.
– Usually inconsequential

35. LUNG ABSCESSES• ASPIRATION
• SEPTIC EMBOLIZATION
• NEOPLASIA
• FROM NEIGHBORING STRUCTURES:
– ESOPHAGUS
– SPINE
– PLEURA
– DIAPHRAGM
• ANY PNEUMONIA WHICH IS SEVERE AND
DESTRUCTIVE, AND UN-TREATED … Kleb., S. aureus
• IF NO CAUSE DETERMINED … PRIMARY CRYPTOGENIC
LUNG ABSCESSES.

36. • Vary in diameter from a few millimeters to large cavities
of 5 to 6 cm
• ASPIRATION … more common on the right, most often
single.
• PNEUMONIA OR BRONCHIECTASIS … usually
multiple, basal, and diffusely scattered.
• SEPTIC EMBOLI & PYEMIC ABSCESSES …multiple
and may affect any region of the lungs.
• Suppurative destruction of the lung parenchyma
within the central area of cavitation.

39. • Manifestations
– cough, fever, and copious amounts of foul-smelling purulent or
sanguineous sputum.
– Fever, chest pain, and weight loss
– Clubbing of the fingers and toes may appear within a few weeks
• Must be confirmed radiologically.
• In older individuals … rule out an underlying carcinoma,
(10% to 15%)
• Complications: Extension into the pleural cavity,
hemorrhage, the development of brain abscesses or
meningitis from septic emboli, and (rarely) secondary
amyloidosis (type AA).

40. CHRONIC Pneumonias
• USUALLY NOT persistences of the community or nosocomial
bacterial infections, but CAN BE, at least histologically
• Often SYNONYMOUS with the 4 classic systemic fungal or
granulomatous pulmonary infections infections, i.e.,
TB, Histo-, Blasto-, Coccidio-
• If you see pulmonary granulomas, think of a CHRONIC
process, often years

41. CHRONIC Pneumonias
•TB
•HISTO-PLASMOSIS
•BLASTO-MYCOSIS
•COCCIDIO-MYCOSIS

42. HISTOPLASMOSIS
• Spores in bird or bat droppings
• Mimics TB
• Histoplasma CAPSULATUM (intracellular)
• Pulmonary granulomas, often large and calcified
• Tiny organisms live in macrophages
• Ohio, Mississippi valley
• MANY other organs can be affected
• In fulminant cases … no granulomas, only
macrophages aggregates

45. BLASTOMYCOSIS• Spores in soil
• Mimics TB, like ALL the granulomatous lung diseases
do.
• Blastomyces DERMATIDIS
• Pulmonary granulomas, often large and calcified
• Large distinct SPHERULES (larger than coccidio)
• Ohio, Mississippi valley, Great Lakes, WORLDWIDE
• MANY other organs can be affected, especially SKIN
• In the normal host, the lung lesions of blastomycosis
are suppurative granulomas.

48. COCCIDIOMYCOSIS
• Spores in soil
• Mimics TB
• Coccidioides IMMITIS
• Pulmonary granulomas, often large and calcified
• Smaller spherules than blasto.
• Tiny organisms live in macrophages
• American SOUTHWEST
• MANY other organs can be affected

50. GRANULOMA

51. COMPROMISED HOSTS
• Defenses are suppressed by
– Disease
– Immunosuppressive therapy for organ or
hematopoietic stem cell transplants
– Chemotherapy for tumors
– Irradiation.
• Infectious agents
– Bacteria (P. aeruginosa, Mycobacterium species, L.
pneumophila, and Listeria monocytogenes),
– Viruses (cytomegalovirus [CMV] and herpesvirus)
– Fungi (P. jiroveci, Candida species, Aspergillus
species, the Phycomycetes, and Cryptococcus
neoformans).

53. HIV Patient
• 30% to 40% of hospitalizations in HIV-infected
individuals.
• Bacterial pneumonias in HIV-infected persons are
more common, more severe, and more often
associated with bacteremia than in those without HIV
infection.
• The CD4+ T-cell count determines the risk of infection
with specific organisms.
– Bacterial and tubercular infections … more than 200
cells/mm3
– Pneumocystis pneumonia … less than 200 cells/mm3
– Cytomegalovirus, fungal, and Mycobacterium avium complex
infections … less than 50 cells/mm3

54. PCP

55. Methenamine SILVER
stain for
Pneumocystis carinii*