ENVIRONMENTAL AND NUTRITIONAL DISEASES PATHOLOGY

MOSUGU O.

AIM

• Describe how the environment affects health
• Have an understanding of drug abuse and its effects
• Have an understanding of the health and morphological effects of alcohol and tobacco use
• Have an overview of how nutrition affects health

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INTRODUCTION

• The environment encompasses all the various outdoor, indoor, occupational and ambient interactions of man
• Environmental pathology refers to the study of diseases arising from mans exposure to his surroundings, workplace and personal environment

CLIMATE AND HEALTH

• Currently, there is an increased awareness to the effects of climate change and its impact on health
• The extent and severity of this effects is still debated
• These effects maybe direct and indirect, immediate or longstanding

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Climate and Health

• Some examples include;
• Increased flooding which has led to the spread of waterborne diseases like cholera and typhoid
• Drought and water shortages has led to malnutrition
• Elevated atmospheric temperature has contributed to the spread of vector borne diseases

Climate change

• Climate change refers to any distinct change in measures of climate lasting for a prolonged period of time. These changes include measures include: changes in temperature, rainfall, snow or wind lasting for decades or longer.
• Climate change may be due manmade or natural factors

Climate change

• Global warming refers to the longterm average increase in atmospheric temperatures near the earth’s surface.
• Greenhouse effect refers to the natural process by which the atmosphere insulates the earth’s surface from the Sun’s radiant energy.
• Greenhouse gases include: H2O vapor, CO2, CH4, N2O, HFC’s and PFC’s

AIR POLLUTION

• Air pollution occurs when harmful gases, fumes, dust or particulates capable of harming human health is introduced into the atmosphere
• Exposure to high levels of air pollutants can result in:

-irritation of the eyes

-Wheezing, coughing, chest tightness and difficulty breathing

-worsening of preexisting lung dz

- Increased risk of heart attacks

AIR POLLUTION

• There are a wide variety of air pollutants including
• Carbon monoxide
• Nitrogen dioxide
• Ozone (ground level)
• Sulphur dioxide
• Lead
• Particulates
• Methane

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Environmental effects of air pollution

• Haze
• Eutrophication
• Crop and plant damage
• Global climate change
• Wildlife effects
• Ozone depletion

XENOBIOTIC METABOLISM

• Xenos GREEK WORD for stranger or foreigner
• Xenobiotic refers to chemical substances considered foreign to the body, e.g drugs and substances of abuse
• These substances may access the body via;
• Oral route
• Percutaneously
• inhalation

Xenobiotic metabolism

• These xenobiotics must be transformed into more stable, less toxic substance via cytochrome p450 enzymes in two stages:
• PHASE ONE-hydrolysis, redox rxns producing more soluble/permeable substrates
• PHASE TWO- conjugation with methyl, glutathione and glucuronyl produces less toxic substrates
• PHASE THREE- Conversion of conjugated metabolites into lipophilic substrates for easy excretion

DRUGS OF ABUSE

COCAINE

• Extract from the leaf of coca plant
• Taken by inhalation, IV injection or orally
• Usual effects include euphoria and drug dependent stimulation
• Effects of high doses include dizziness, tremors, seizures, hallucinations, nausea and vomiting and angina

DRUGS OF ABUSE

HEROIN

• An opioid derivative similar to but more potent than morphine
• Produces euphoria followed sedation, anaesthetic effect
• In high doses produces bradycardia, respiratory depression, death most commonly follows respiratory depression or asphyxiation

DRUGS OF ABUSE

HALLUCINOGENS

-Phencyclidine aka angel dust produces anaesthetic effects and potential for self harm

-LSD produces hallucination, anxiety and sympathomimetic effects

AMPHETAMINES

Potent CNS stimulant

Examples include: speed, ice etc

Used to treat ADHD

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HORMONES

Oral contraceptives

• Harmful effects arise mainly from effects on blood vessels (thrombosis) and also from increased risk in certain neoplasms

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TOBACCO

the no. 1 contributor to morbidity and mortality in developed climes.

Some diseases associated with tobacco include:

1. Cardiovascular disease
2. Lung cancer
3. COPD (Emphysema and Chronic Bronchitis)
4. Other cancers(oral, esophageal, bladder, kidney, pancreas)

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• Effects of tobacco smoking is dose and duration dependent
• Cessation of smoking can lead to reversal of some harmful effects
• Cigarette smoke contains over 2000 known chemical substances. Nicotine (addictive), carcinogens (polonium-210, PAH, benzene, nitrosamines, aldehydes etc)

ALCOHOLISM

• Alcohol is ingested in various forms
• Effects maybe acute or chronic
• Chronic alcoholism refers to regular intake of sufficient to produce psychological, social or physical injury to an individual
• The specific limits for intoxication vary for individuals
• >45g should be discouraged and >100g potentially harmful

Alcohol and Organ Effects

Liver

Alcoholic liver disease( fatty liver, alcoholic hepatitis and cirrhosis)

Pancreas

Acute and chronic pancreatitis. Chronic calcifying pancreatitis

Heart .

Alcoholic cardiomyopathy leads to low output CCF

Skeletal Muscle

Alcoholic myopathy produces skeletal muscle weakness. Alcoholic rhabdomyolysis

is rare but can be fatal.

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Endocrine System

Particularly affects males, producing feminization, loss of libido and gynecomastia

Gastrointestinal System

Reflux esophagitis, Mallory-Weiss syndrome and malabsorption in small intestine

Hemopoietic system

Megaloblastic anemia from malabsorption and antagonistic effects. Hemolytic anemia results from splenomegaly

Bone

Osteoporosis and aseptic necrosis of the head of femur

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Nervous system

Generalised cortical atrophy

Wernicke Encephalopathy

Korsakoff psychosis

Alcoholic cerebellar degeneration

Central pontine myelinolysis

Amblyopia

Peripheral neuropathy

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Fetal Alcohol Syndrome

• Occurs in approx 6% of alcoholic mothers
• Mental retardation
• Microcephaly
• Facial abnormalities
• Neurologic dysfunction
• Other congenital abnormalities

METALS

Lead

• Microcytic hypochromic anemia is a cardinal feature of lead poisoning

Peripheral motor neuropathy in adults, lead encephalopathy in children

Lead nephropathy produces aminoaciduria, glycosuria and hyperphosphaturia

METALS

Mercury

Produces nephrotoxicity and neurotoxicity

Iron

Iron deficiency produces anemia. Excessive ingestion produces Bantu hemosiderosis

Cadmium, Arsenic, Chromium and Nickel all have putative effects based on epidemiologic studies

THERMAL INJURY

Hypothermia

May be local or generalised

generalised hypothermia reduces core body temperature and central blood flow.

Produces death via cardiac arrhythmia

Lethargy, withdrawal and inappropriate behavior.

Morphology shows skin discoloration, ear and hand swelling

THERMAL INJURY

Localised hypothermia

Occurs as either trench/immersion foot or frostbite

Frostbite results from the crystallization of tissue water

Trench foot results from prolonged exposure to supra-freezing temperatures. Resulting in endothelial damage which produces thrombosis and then gangrene

THERMAL INJURY

HYPERTHERMIA

Thermal injuries produce endothelial injury and then altered vascular permeability, edema and blistering

Burns

1. Cutaneous burns
2. Inhalation burns
3. Electric burns

• Some conditions producing systemic hyperthemia

1.Malignant hyperthermia: follows anesthesia in susceptible persons with mutations affecting either the SR ryanodine receptor(RYR1) or a voltage gated calcium channel(CACNA1S)

2. Heat Stroke: follows high ambient temperatures or vigorous exercise

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PHYSICAL INJURIES

• The effects of mechanical trauma is dependent on:
• The force transmitted
• The rate at which the transfer occured
• The surface area to which the force is applied
• The area of the body

PHYSICAL INJURIES

• A contusion is localised mechanical injury with focal hemorrhage
• Abrasion- this is a skin defect caused by a crushing force or scrape
• Lacerations represent a split or tear of the skin resulting from a force greater than an abrasion
• Wounds- these are mechanical disruptions of tissue integrity

NUTRITIONAL DISORDERS

• MALNUTRITION is defined as the cellular imbalance between supply of nutrients and energy and the body’s demand for them to ensure growth, maintenance and specific functions
• Malnutrition may be primary or secondary

• PROTEIN ENERGY MALNUTRITION

Inadequate intake of protein and calories

PEM is subdivided into 2 main clinical syndromes:

1. Marasmus
2. kwashiorkor

NUTRITIONAL DISORDERS

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MARASMUS

-arises from a global deficiency of all elements of the diet. Simply put, it denotes a deficiency of calories from all sources.

-pathologic changes include:

↓body weight, ↓ subcutaneous fat, protuberant abdomen, muscle wasting and wrinkled face. Edema is characteristically absent

-Histology shows organ atrophy and lipofuscin pigment in most organs

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• KWASHIORKOR

Results from deficiency from protein in diets relatively high in carbohydrates

Typically follows too early weaning off breast milk

Characterised by hypoalbuminemia and generalised dependent edema

Weight is between 60-80% of expected for age

• KWASHIORKOR CONTINUED

-↓muscle and subQ fat, with large head, anemia and immune deficiency

-Loss of appetite, apathy and listlessness

-FLAG SIGN may be seen in the hair. Flaky paint lesion on the skin

-Morphology shows hepatomegaly and fatty liver, organ atrophy ( cerebral atrophy, BM hypoplasia, lymphoid atrophy) but subQ fat is preserved.

Obesity

• Defined broadly as excess body weight for a given height. BMI> or = 30kg/m2
• Complex aetiology/pathogenesis

involving: Environmental, genetic, medical, physiological and social factors.

Neurohumoral mechanism believed to involve a control circuit involving; ghrelin, leptin, Melanocortin control, TRH and autonomic pathway

Complications of obesity

• CVS: HTN, IHDz, CVDz, DVT, CCF etc
• Respiratory: obstructive sleep apnea, Pickwickian syndrome
• Neoplastic: cancers of esophagus, colon, breast etc
• CNS: idiopathic intracranial hypertension (pseudotumor cerebri)
• MSS: Osteoarthritis, gout, low back pain

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Complications of obesity

• GIT: Cholelithiasis, fatty liver, GERD, hernia and pancreatitis
• Ophthalmologic: cataracts
• Endocrine: metabolic syndrome, DM,PCOS
• GYNECOLOGIC: abnormal menstruation, infertility

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VITAMINS

Vitamin A

-Functions in normal vision, regulation of cell growth, immune functions and lipid metabolism

• Deficiency results in squamous metaplasia esp in glandular epithelium ( eyes- xerophthalmia, keratomalacia) and results in immune deficiency
• Vitamin A toxicity produces pseudo-tumor cerebri, hepatomegaly, splenomegaly and ↓bone density

VITAMIN B COMPLEX DEFICIENCY

-Vitamin B1- Beriberi, neuropathy, cardiac failure, Korsakoff’s psychosis and Wernickes encephalopathy

-B2- mucosal fissuring, cheilosis, angular stomatitis and glossitis

B6- cheilosis, glossitis, neuropathy, sideroblastic anemia

B12- megaloblastic anemia, SACD

B9- megaloblastic anemia, neural tube defects, mouth ulcers

B3- pellagra (dermatitis, diarrhea, dementia)

VITAMIN C

-deficiency results from lack of fresh fruits and vegetables

-vitamin C is needed for collagen synthesis

- Deficiency results in delayed wound healing, gingival bleeding, petechiae and ecchymosis. Less commonly soft bones and growth retardation.

• VITAMIN D
• Functions in maintenance of plasma levels of Ca and Po.
• Photosynthetic activation of 7-dehydrocholesterol produces cholecalciferol (Vit D3)
• Deficiency produces Rickets or Osteomalacia

THANK YOU