ENVIRONMENTAL PATHOLOGY
-all diseases that are not entirely genetic, are influenced by
environmental factors
limitations: even genetic diseases are influenced by environmental
factors
-most diseases are multifactorial
“environmental diseases”
1- d. resulting from the pollution of environment, particularly the air
2- d. due to abuse of drugs and physical agents
3- d. due to over or undernutrition
1. ENVIRONMENTAL POLLUTION
-pollution of environment and particularly the air is rapidly becoming
a major problem in industrialized areas
air is polluted by industrial waste and products of car exhausts, etc
-food and water may be polluted by pesticids and herbicids
-food and water could be contamined by microbes- still the most
important cause of morbidity in third world
pollutant - is defined as an agent in the environment, the presence of
which may cause disease in those who are exposed
pollutants may cause diseases
-by direct toxic immediate effects
-by long- term effects
acute toxicity may result in necrosis, acute inflammation or indirectly
through hypersensitivity immune response
more difficult to study are long-term effects - these may have forms of
chronic inflammation, fibroproduction, degenerative changes, may
produce mutations, may result in cancer, cause congenital defects,
etc...
AIR POLLUTION
SMOG - visible accumulation of air pollutants -coal dust particles,
automobile exhaust fumes, sulphur oxides, nitrogen oxides and
carbon dioxide- CO2
-air pollutants may affect various organs, but most important
are the lungs
-pulmonary diseases, such as pneumoconiosis silicosis
-asbestosis and related diseases
 PNEUMOCONIOSIS = chronic lung disease resulting from the
inhalation of mineral dusts
there are several most common types of pneumoconioses: nearly in all
cases due to chronic exposure at workplaces
-result from the exposure to coal dust- anthracosis
-to dust with silica particles- silicosis
-with asbestos particles- asbestosis
-and with beryllium-berylliosis
pathogenesis:
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-the reaction of the lungs to mineral dusts depends on various
factors such as the size and shape of the particles, solubility and
reactivity of particles,
coal dust is relatively inert, small amounts do not cause lung disease
large amounts must be deposited in the lungs before the disease is
detectable clinically
silica, asbestos and beryllium are more reactive than coal dustfibroproduction even in lower concentrations
-inhaled particles are removed by cilliary movement of mucosa
of respiratory tract, some particles may be taken up by epithelial cells,
the other particles cross epithelial cell lining and may be entrapped by
interstitial macrophages -(deposited in lungs as alveolar macrophages)
-or may reach lymphatics and lymph nodes
macrophages may be activated- stimulsted macrophage produce
mediators -such as cytokines, fibroblast-stimulating factor,
fibronectin, platelet- derived growth factors, TNF, etc - which play key
role in fibrogenesis
important factors determinating clinical course are
-concentration of particles
-length of exposure
-tobacco smoking worsens the effects of all inhaled mineral
dusts
 PNEUMOCONIOSIS - includes a spectrum of lung diseases
1) pulmonary anthracosis
2) simple coal workers pneumoconiosis CWP
3) complicated CWP
1 ) PULMONARY ANTHRACOSIS
-most common disorder- coal dust-induced pulmonary lesioncoal miners, commonly seen in all people living in the cities, in
tobacco smokers
morphology:
-carbon pigment is engulfed by alveolar macrophages
-carbon pigment also occurs in interstitial macrophages accumulation in the vicinity of large vessels, bronchi and scars in the
lungs
-marked anthracotic pigmentation of regional lymph nodes
2) SIMPLE COAL WORKERS PNEUMOCONIOSIS
-is characterized by occurrence of coal macules (composed of
dust-laden macrophages) and coal nodules (composed of groups of
macrophages with small amount of collagen fibers)
-these coal macules and nodules are scatterd through out the
lungs, mostly infiltrated are upper lobes
the site of early dust accumulation- vicinity of small bronchioli and
vessels
3) COMPLICATED COAL WORKERS PNEUMOCONIOSIS
-occurs in a background of simple CWP- requires years to
develop
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it is characterized by large scars heavily infiltrated with anthracotic
pigment particles - consist of dense hyalinized collagen. The centers of
these scars may be necrotic
Clinical significance:
pulmonary anthracosis and mild cases of CWP are benign, no or mild
abnormalities of lung function
complicated CWP - results in progressive pulmonary fibrosis,
increasing pulmonary dysfunction, pulmonary hypertension- cor
pulmonale chronicum- right ventricle failure
increased susceptibility for pulmonary tuberculosis
SILICOSIS
-is a lung disease caused by inhalation of crystalline silicon
dioxide (silica particles)
-is among the most important occupational diseases
morphology:
-silicosis is characterized in early stage grossly by multiple tiny,
barely palpable small nodules (pale to black) in upper lobes of lungs
in progressive stage- large nodules throughout the lungs- nodules
coalesce to form hard collagenous scars and masses- some nodules
undergo softening- due to central necrosis
microscopicallynodules consist of concentric layers of hyalinized collagenexamination by polarized microscopy reveals birefringent silica
particles
clinical course:
the disease is progressive, impaired pulmonary function results in
pulmonary hypertension and heart failure
ASBESTOSIS
-severe lung disease caused by inhalation of asbestos polluted
air
-occupational disease
asbestosis is linked to the following lung diseases and complications
1) interstitial lung fibrosis
2) increased risk of bronchogenic carcinoma
3) causes recurrent pleural effusions, development of fibrous pleural
plaques or diffuse pleural fibrosis
4) increased risk of induction of malignant mesothelioma of the pleura
morphology:
-marked diffuse lung interstital fibrosis - begins as fibrosis
around respiratory bronchioles more often in lower lobes- distortion of
original architecture
-presence of asbestos bodies - golden-brown rods with
translucent center, which consists of asbestos coated with
proteinaceous substance containing iron
asbestosis
-visceral pleura undergoes fibrous thickening
-pulmonary scarring
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chronic lung asbestosis results in pulmonary hypertension and
chronic right-sided heart failure
clinical course:
similar as in progressive silicosis
BERYLLIOSIS
-is lung disease caused by heavy exposure to airborne dusts or
to fumes containing beryllium
-occupational disease of workers in aircraft and nuclear
industry
- chronic berylliosis is caused by induction of cell- mediated
immunity
it appears that genetic susceptibility is necessary for induction of
immune response (only 2 % of exposed persons develop the disease )
morphology:
-noncaseating granulomas in lungs, hilar lymph nodes, and less
commonly in spleen, kidney, liver etc.
clinical course:
dyspnea, cough, weight loss, progressive pulmonary failure

2. DISEASE CAUSED BY ABUSE OF DRUGS

Injury by nontherapeutic toxic drugs
ALCOHOL
Drug abuse- is the use of a mind-altering substance in a way
that differs from generally approved social practices
-in excess, alcohol may cause marked physical and psychologic
damage disorders directly associated with abuse of alcohol include
- acute alcohol intake- the major effects of are exerted on the
CNS, may induce also hepatic and gastric acute injury
-chronic abuse - causes alterations in many organs and tissues,
particularly the liver and stomach, and pancreas
LIVER- alcohol is the most common cause of hepatic injury- alcohol
liver disease, finally resulting in liver cirrhosis
- possible causes of death in chronic alcoholics- massive
bleeding from gastric or duodenal peptic ulcers or from esophageal
varices (associated with cirrhosis)
PANCREAS- excess in alcohol use- increases the risk of acute and
chronic pancreatitis
STOMACH- massive bleeding from gastric ulcer- can be fatal
CNS- chronic abuse causes cerebral atrophy, peripheral neuropathies
CARDIOVASCULAR SYSTEM- increased incidence of hypertension and
congestive cardiomyopathy
FETAL ALCOHOL SYNDROME- massive abuse of alcohol in pregnancy
can cause growth retardation and mental disorders in a newborn child
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
Injury by therapeutic agents (adverse drug reactions)
EXOGENOUS ESTROGENS AND ORAL CONTRACEPTIVESestrogen therapy widely used in postmenopausal women
-adverse effects include: unopposed estrogen therapy
increases the risk of endometrial cancer
-increases the risk of breast cancer
-synthetic estrogens stimulate production of coagulation
blood factors- higher risk of thromboembolism
-positive influence of estrogen therapy on cardiovascular
systém- decrease in risk of atherosclerosis, protective effect of
estrogen
ASPIRIN- acute overdose (in suicide)- metabolic acidosis
-chronic aspirin toxicity- CNS changes, such as headache, nausea,
vomiting, mental confusion
-acute erosive gastritis- gastrointestinal bleeding
-chronic abuse of aspirin and phenacetin-results in analgesic
nephropathy
3. NUTRITIONAL DISEASES
-in most of the highly industrialized countries- diseases
associated with overnutrition are very common - such as diabetes
mellitus, obesity, atherosclerosis, hypertension, hypercholestrolemia
on the other hand, in third countries- protein-energy malnutrition
PEM- refers to a range of clinical symptoms characterized by
inadequate intake of calories and proteins
the most affected are children
morphology and diagnosis:
- children suffer of growth retardation, loss of weight, loss of fat and
muscles
-anemia and manifestation of multivitamin deficiencies
-immune deficiency

KWASHIORKOR
-occurs when protein deprivation is relatively greater than the
reduction of total calories- marked protein deprivation- causes
hypalbuminemia- generalized or dependent edema
enlarged fatty liver- owing to decreased synthesis of proteins
decreased immunity with increased susceptibility to infections
hypoplastic bone marrow owing mainly to decreased RBCs
VITAMIN DEFICIENCIES- read in textbooks (pp.244-255)
OBESITY is common condition with a increasing tendency in
occurrence
obesity - increases the risk for development of diabetes mellitus,
hypertension, hypertriglyceridemia, HDL cholesterol, coronary artery
disease, cholelithiasis- is 6 times more common in fat people
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-hypoventilation syndrome- is respiratory failure in very obese
people- it is called „pickwickian syndrome“ after the fat man by the
name Mr. Pickwick who was described by Dickens in his famous novel
-it is characterized by somnolence and right-sided heart failure
-degenerative joint diseases
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