Histological slides regarding pneumonia: Note, all slides are H&E.

First and foremost, a slide of how a NORMAL lung looks like.

Gross microscopy.

This is a low-magnification view of part of a lobule. It has small airways (bronchioles (B)) with adjacent branches of the pulmonary artery (A). The blood flows from the arteries into fine capillaries in the alveolar walls (the diffuse network) where gas exchange occurs. The blood then flows into the pulmonary veins (V) that carry the oxygenated blood back to the heart.

Detailed close up.

Note the cilia on the cell surface.

Cryptoccocal pneumonia: A complication of crytoccosis. Often by cryptoccocus neoformans.

low power magnification.

high power magnification.

Because of the presence of the giant cells, this pattern is also referred to as "granulomatous infiltrate”. Cryptococci possess a large capsule so they tend to stand out in the cytoplasm of the giant cells. The giant cells are unique participants in our response to this type of injury. They are commonly seen in association with inflammatory responses to tuberculosis and foreign material that has been injected or left behind in the body.

Lung with lobar pneumonia: A form of pneumonia that affects a large and continuous area of the lobe of a lung.

low power

high power

Infiltrate in the alveolar spaces with the inflammatory response expected against a bacteria (lots of polymorphonuclear leukocytes).

Interstitial pneumonia: A group of diffuse lung diseases. It is a term used for a type of diffuse parenchymal lung disease (DPLD), also called interstitial lung disease (ILD).

Due to the many types, it is very hard to classify. Below are some common characteristics of this type.

There is evidence of previous inflammation of the pleura, as noted by the scarring, plus changes of emphysema.

Here you will see the infiltrate is interstitial (not within the alveolar air spaces), and consists almost exclusively of lymphocytes.

Progressed form of usual interstitial pneumonia. From a surgical lung biopsy at low magnification

Has the appearance of honeycomb pattern. in a surgical lung biopsy at low magnification. The dilated spaces seen here are filled with mucin.

Vaccines Related to Pneumonia prevention:

There are several vaccines that prevent infection by bacteria or viruses that may cause pneumonia. These vaccines are against:

Streptococcus pneumonia

2 kinds which are:

1) Polysaccharide vaccine

The polysaccharide vaccine is the most commonly used vaccine against pneumococcal infection presently. It consists of purified polysaccharides from 23 serotypes (1, 2, 3, 4, 5, 6b, 7F, 8,9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F and 33F). Immunity is induced primarily through stimulation of B-cells which release IgM without the assistance of T cells. However, theimmune response is less robust than the response provoked by conjugated vaccines, which has several consequences. The vaccine is ineffective in children less than two years old, presumably due to their less mature immune systems. Non-responders are also common amongst older adults. Immunization doesn’t last, so individuals must be re-vaccinated every 5–6 years. Mucosal immunity is unprovoked; hence the vaccine does not affect carrier rates, or protect from upper or lower respiratory tract infections.

2) Conjugated Vaccine

The conjugated vaccine consists of capsular polysaccharides covalently bound to the diphtheria toxoid CRM197, which is highly immunogenic but non-toxic. This combination provokes a significantly more robust immune response by recruiting CRM197-specific type 2 helper T cells, which allow for immunoglobulin type switching (to produce non-IgM immunoglobulin) and production of memory B cells. Among other things, this results in mucosal immunity and eventual establishment of lifelong immunity after several exposures. The main drawbacks to conjugated vaccines are that they only provide protection against a subset of the serotypes covered by the polysaccharide vaccines.

Haemophilus influenzae type b

The Hib vaccine comes in 3 types:

1) Polysaccharide vaccine

It is a pure polysaccharide vaccine. Similar to other polysaccharide vaccines, immune response to the vaccine was highly age-dependent. Children under 18 months of age did not produce a positive response for this vaccine. As a result, the age group with the highest incidence of Hib disease was unprotected, limiting the usefulness of the vaccine. The vaccine was withdrawn from the market in 1988.

2) Conjugate vaccine

This vaccine works by attaching Hib polysaccharide to a protein carrier which greatly increased the ability of the immune system of young children to recognize the polysaccharide and develop immunity. There are currently three types of conjugate vaccine, utilizing different carrier proteins for the conjugation process, all of which are highly effective and safe: inactivated tetanospasmin (also called tetanus toxoid), mutant diphtheria protein, and meningococcal group B outer membrane protein.

3) Combination vaccines

Generally, it means using multiple combinations of Hib and other types of vaccines to reduce the number of shots necessary to vaccinate a child. Hib vaccine combined with diphtheria-tetanus-pertussis–polio vaccines and Hepatitis B vaccines. The World Health Organization (WHO) has certified several Hib vaccine combinations, including a pentavalent diphtheria-pertussis-tetanus-hepatitis B-Hib, for use in developing countries. There is not yet sufficient evidence on how effective this combined pentavalent vaccine is in relation to the individual vaccines.

Note, most of the common Hib vaccines are only found in the US and are fairly uncommon in SEA or other developing countries.

Bordetella pertussis

Mostly comes in the form of conjugation vaccines much like the example for Hib above.

1) DTaP-HB-IPV-Hib (105) (Diphtheria, Tetanus, Pertussis, Hepatitis B, Polio and Haemophilus influenzae type b) same vaccine as the one above. Three doses are given to children under the age of 7 years, usually at 2, 4 and 6 months of age.

2) DTaP-IPV-Hib (15b) (Diphtheria, Tetanus, Pertussis, Polio, Haemophilus influenzae Type b) A single dose is given as a booster to children at 18 months of age after completing a three dose primary series of DTaP-HB-IPV-Hib.Some children may receive DTaP-IPV-Hib as a three dose primary series at 2, 4 and 6 months followed by a booster dose at 18 months.

3)One dose of DTaP-IPV (15a) (Diphtheria, Tetanus, Pertussis, Polio) vaccine is given to children 4 to 6 years of age (as they start school).

4)Grade 9 students should get a single booster shot of Tdap (18c) (Tetanus, Diphtheria, Pertussis) to boost their immune response if they have been immunized earlier in life.

5) The Tdap (18c) (Tetanus, Diphtheria, Pertussis) vaccine is recommended and free for adults who were not immunized against pertussis as children. The vaccine is also recommended once in adulthood for those who were immunized in childhood to boost protection against pertussis. Once fully immunized, the Tdap vaccine is around 85% effective in protecting you against pertussis. This is free in the US