Chapter 1
Veterinary General Medicine

INTRODUCTION
General systemic states
• DEFINITION: Systemic alterations that are
contributed from many diseases
• Examples are toxemia, fever, septicemia and
hyperthermia.

Con…
1.1. Toxemia: refers to the presence of toxins in the
blood
It is a generalized/systemic disease state caused by
the presence of toxins derived from bacteria or
injured body cells/tissues.
• This state doesn’t not include the diseases caused by
plants or insects or ingested organic or inorganic
poisons

Classification of toxins
• 1. Antigenic toxins
• 2. Metabolic toxins.
• 1. Antigenic toxins: toxins produced mainly by bacteria and to less
extent by helminthes parasites
• Act as antigens and stimulate the development of antibodies.
 Antigenic toxins are divided into:-
 Exotoxin
 Endotoxin
 Enterotoxins

Con…
• 1. Exotoxins: toxins (proteins) produced inside certain
species of pathogenic bacteria
• These are gram-positive bacteria (cell wall-40 layers of
peptidoglycan)
• They produce it during their multiplication (growth and
metabolism).
• The exotoxins are secreted or released in to the surrounding
media following lysis.
• They are heat labile toxins.

Con…
• The important bacterial exotoxins are those produced by
Clostridium spp., and for which commercial antitoxins are available.
• Toxemia due to the exotoxins of Clostridium species can be:
 Ingested as preformed in botulism (ex., botulin toxin of Cl.
Botulinum)
 Produced by heavy growth in the bowel e.g., enterotoxaemia, E.coli
or enterotoxaemic clostridia (C1. perfringens (A–E)).
 Grow in tissues and produce toxin as in blackleg and black disease

Con…
2. Enterotoxins:
 Those are exotoxins and exert their effect
principally on the mucosa of the intestine causing
disturbances of fluids and electrolyte balance.
 Example: enterotoxin released by enterotoxigenic
E.coli, which causes a hypersecretory diarrhea in
neonatal farm animals

Con…
3. Endotoxins:
• It is produced from lipopolysaccharide structural components of cell wall of
Gram Negative Bacteria (40% of cell wall is LPS).
• Heat stable
• Get in to the medium and into the systemic circulation only when the
bacterial walls break down and liberate them, i.e., released during lysis of the
cell (needs cell lysis or death of bacteria)
• The presence of endotoxins in the blood is known as endotoxemia and is
very common form of toxemia in farm animals

Con…
• In ruminants, causes are: E.coli, Salmonella spp., Pasteurella spp.,
and Haemophilus.
• Most of them are normal floras of the intestinal tract.
• Endotoxemia is characterized clinically by abnormalities of all
major body systems.
• These abnormalities include:
 Marked alterations in cardiopulmonary function
 Abnormalities in blood cellular elements (leukons and
thrompocytes), often leading to coagulopathies

Con…
 Change in vascular integrity
 Decreased organ blood flow and metabolism leading to
heart and renal failure
 Major changes in gastrointestinal function, especially
motility
 Decreased perfusion of peripheral tissues leading to shock.
 The need for intensive and complex therapy
 A high case fatality rate.

Con…
• The most causes of endotoxemia in horse are associated
with disease of the gastrointestinal tract including colitis,
intestinal strangulation and obstruction or ileus.
• Complications associated with foaling and grain overload
are also common causes.
• N.B. the endotoxins are not ordinarily absorbed through the
intestinal mucosa unless it is injured as in enteritis or acute
intestinal obstruction

Con…
• If small amount of it is absorbed in to circulation, it is
detoxified by the liver but if hepatic efficiency is reduced or the
amounts of toxins are large, a state of endotoxemia is produced.
• Endotoxins may be absorbed in large amount from sites other
than intestine including the mammary gland, peritoneum,
abscess and other septic foci or from large areas of injured or
traumatized tissues.
• The best known endotoxins are those of E.coli and Salmonella
spp.

Con…
• Varying degree of severity of toxemia occur in
disease such as mastitis, peritonitis, pneumonia
and pleuritis, pericarditis, septic metritis,
septicemia of neonates, myositis,
meningoencephalitis and some enteritides.

1

Con…
2. Metabolic toxins
• These are toxins produced by body metabolism
• Toxin will be accumulated and developed in to toxemia if only if
there:
 incomplete elimination or higher production-due abnormal
metabolism or
 when the normal mechanisms of detoxifications are disrupted,
mainly in hepatic dysfunction, the toxins accumulate beyond the
critical point and resulted in a state of toxemia.

Con…
• Obstruction of lower alimentary tract
• Example are:
 Phenols
 Cresols
 Amines
 Ketone and lactic acidemia

Con…
Reason for accumulation
 Incomplete elimination
 Higher production-due to abnormal metabolic
process in the cell
 Obstruction of lower alimentary tract
• Significance: play important role in
pathogenecity but they don’t stimulate immunity

Con...
 The most common metabolic toxemias in animals are:
 Ketonaemia
 Lactic-acidaemia
 Ketonaemia/ Pregnancy toxemia is caused by disproportionate fat
metabolism characterized by hyperketonemia, ketonuria, ketolactin
and hypoglycemia mostly in large and small ruminants and pigs.
 In sheep and goats the disease is known as pregnancy disease,
lambing sickness and twin-lamb/kid disease.

Con…
• The principal cause of pregnancy toxemia is low
blood sugar (glucose).
• Lactic-acidaemia: is a metabolic toxemia caused
by acute ruminal impaction of rumen by easily
digestible carbohydrate rich animal feeds.
• Also known as Lactic acidosis/metabolic
acidosis Carbohydrate engorgement

Toxomeia-diagnosisosis
Theoretically the diagnosis of toxemia should
depend on the isolation of the toxin causing
toxemia.
But practically diagnosis is based on
observation of the common clinical signs for
early treatment.

Treatment of endotoxemia
 The principles of treatment of toxemia should be directed
towards
 Removal of the foci of infection
 Administration of antimicrobial agents
 Aggressive fluid and electrolyte therapy to combat the
relative hypo-volemia, hypoglycemia and electrolyte and
acid-base disturbance

Con…
 Using of anti-inflammatory pre-parates like that of
glucocorticoides (e.g., prednisolone,
methylprednisolone and Dexamethasone)
 Treatment of toxemia should be directed towards
removal of the toxin and provision of specific
antitoxins.