Category Archives: Bacterial infection

PYEMIA

Posted by on January 30, 2012 No comments

PYEMIA

Definition:

It is a condition in which multiple small abscesses are formed in different organs due to circulation and impaction of septic emboli.

Characters of pyemia abscesses:

They are multiple, small and nearly of the same size, usually peripheral, yellow in color and surrounded by a zone of congestion.

Pathogenesis of pyemia:

1.     Pyemia starts by inflammation and thrombosis in a vein (thrombophlebitis).

2.     The thrombus become infected, fragmented and circulate as septic emboli.

3.     Septic emboli are impacted in the organs forming multiple abscesses.

 

Types of pyemia: There are two types:

1.     Systemic

2.      Portal

1. Systemic pyemia: occurs when the septic emboli and the organisms are carried by the systemic veins as occurs in:

a.   Puerperal sepsis.

b.   Acute haematogenous osteomyelitis.

c.   Acute bacterial endocarditis.

d.   Suppurative   otitis   media   with   lateral   sinus
thrombosis.

e.   Suppurations of the face with cavernous sinus
thrombosis.

Sites of systemic pyemia:

The pyemic abscesses in systemic pyemia form primarily in the lungs but may also occur in the kidney, liver, and brain. 2. Portal pyemia: in which the septic emboli and the organisms are carried by the portal veins as occurs in.

a.   Acute suppurative appendicitis.

b.   Infected thrombosed pile.

c.   Septic lesions of the gall bladder, colon or rectum.
Sites of portal pyemia:

The pyemic abscesses in portal pyemia form in the liver.

 

Pyemic abscesses: They are multiple,small and surrounded by zone of congestion .

SEPTICEMIA

Posted by on January 30, 2012 No comments

SEPTICEMIA

Definition:

It is the circulation and multiplication of virulent organisms in the blood, with the production of severe constitutional symptoms and various structural changes. Causes of septicemia:

Septicemia is produced by all pyogenic organisms but the commonest is streptococcus hemolyticus. It is a rare disease now since the introduction of antibiotics. It can complicate the following diseases and conditions:

a.   Puerperal sepsis or suppurative endometritis.

b.   Acute hematogenous osteomyelitis.

c.   Septic wounds particularly those of the hands and
foot.

d.   Prick wounds by infected pin pointed instrument or
surgical instruments in operations and shoe-makers.

e.   Gonorrhea.

Very important is the low resistance of the patient

 

Pathological features of septicemia:

1.    Petechial hemorrhages all over the body e.g. in the skin, mucous membranes and serous membranes. This is due to destruction of endothelial lining of the capillaries by the streptococcal toxins.

2.    The blood becomes fluid and is not clotted in the post mortem. This is due to hemolysis of the blood by hemolysins liberated by the streptococci.

3.    The spleen shows a characteristic appearance which is called acute splenic swelling and is pathognomonic of septicemia. The spleen is moderately enlarged and very soft. The cut section shows a semifluid dark red pulp which can be easily washed by tap water.

4.    Cloudy swelling, fatty change and foci of necrosis in the heart, kidney and liver.

5.    The valves of heart may be invaded, a condition called (acute bacterial endocarditis). Vegetations (i.e. thrombi on the valves) are formed. It may break off and circulate as septic emboli leading to pyemia.

TOXEMIA & BACTEREMIA

Posted by on January 30, 2012 No comments

TOXEMIA

Definition:

It is the circulation of bacterial toxins in the blood with the production of clinical manifestations and pathologic changes.

Effects and manifestations of toxemia

1.   General or clinical manifestations: in the form of fever, rigors, sweating, headache, pain all over the body and rapid weak heart beats. There is increased catabolism resulting in loss of weight (i.e. fever is always accompanied by increased tissue metabolism which depletes the body storage of fat and carbohydrate leading to loss of weight).

2.    Degeneration: fatty changes and cloudy swelling in the heart, kidney and spleen.

3.    Depression of the bone marrow leading to anemia of the normocytic type, especially in chronic toxemia.

 

 

 

BACTEREMIA

Definition:

It is the mere circulation of bacteria in the blood or it is the transient presence of bacteria in the blood. The bacteria may be derived from a septic focus of infection some where in the body e.g. in the tonsils (tonsillitis), nasal sinuses (sinusitis) and gall bladder (cholecystitis). Effects of bacteremia:

a.  When small numbers of organisms enter the blood they
are rapidly phagocytosed by the cells of the
reticuloendothelial system and destroyed.

b. When larger numbers of organisms enter the blood one of
the following effects may result:

1. Rigors may occur as in bacteremia which follows catheterization.

2.      When bacteria lodged in the bone. Staphylococci may cause acute suppurative osteomyelitis. Trauma to the limb leads to mild injury at the metaphysis of a long bone, and this cause localization of the staphylococci in the hematoma produced.

3.      When the bacteria lodged into the heart (streptococci viridance may cause subacute bacterial endocarditis) if the patient is predisposed to by a previous rheumatic heart or a congenital heart disease.

4.      In bacteremia the kidney may filter off the organisms and a renal infection occurs.

BACTERIAL INFECTION

Posted by on January 30, 2012 No comments

BACTERIAL INFECTION

The term bacterial infection means invasion of the body by disease producing organisms (i.e. pathogenic organisms) and the subsequent pathologic changes in the tissues. The effects of infection: These depend on two factors:

1.      The resistance of the body.

2.      The strength of the organism, which is determined by the virulence of the organism and the dose of infection.

The power of organism to produce disease lies in its capacity:

■       To produce toxins (exogenous toxins or endogenous toxins) or induce hypersensitivity reactions.

■       Inflammation is the local reaction of the body against bacterial infection.

■       Inflammation aims at localization of infection, but if the localizing mechanism fails, the infection spreads.

Spread of infection occurs to:

1.      The surrounding tissues.

2.      Then to lymphatics.

3.      And to blood vessels.

 

■       Finally the organisms or its toxins reach the circulation and become generalized all over the body resulting in.

■       Toxemia, bacteremia, septicemia, or pyemia.