Ch 9 Flashcards
(119 cards)
1
Q
What diseases are caused by greenhouse gases and climate change? 4
A
- Cardiovascular/Cerebrovascular/Respi - heatwaves and air pollution
- Gastroenteritis - cholera due to water pollution
3.vector borne infections eg malaria increased weather temp
4.Malnutrition - reduced crop production
2
Q
What is a Xenobiotic?
A
Exogenous chemicals in environment - air, water, food and soil which can become toxic or non toxic compounds
3
Q
The most important catalyst of phase I reactions are (group of enzymes)
A
Cytochrome p450
4
Q
What does the cytochrome P450 do?
A
Catalysed reactions that detoxify xenobiotics or convert them to active compounds that cause cell injury
5
Q
What is smog?
A
Smoke and fog
6
Q
What are examples of outdoor air pollutants?
A
Ozone
Lead
CO
Sulfur dioxide
7
Q
What is the affinity of CO to Hb?
A
200x
8
Q
What happens to CO in the environment?
A
Becomes oxidised to CO2
9
Q
How does CO poisoning cause death?
A
CNS depression –> coma
10
Q
Where are ischemic changes seen in the brain of CO poisoning?
A
Basal ganglia
Lenticular nuclei
11
Q
What is the classic sign of acute CO poisoning in a fair skinned person?
A
Cherry Red skin and mucous membranes (high levels of carboxy haemoglobin)
12
Q
What test is used to diagnose CO poisoning?
A
Blood levels of carboxyhb
13
Q
The no 1 cause of lung cancer in non smokers is from (pollutant)
A
Radon
14
Q
—-(pollutant) can cause legionnaires disease and viral pneumonias
A
Bioaerosols (from pet dander, dust mites)
15
Q
Formaldehyde is considered a (term)
A
Carcinogen
16
Q
How does lead cause disease?
A
Binds to sulfhydryl groups on proteins and interferes with calcium metabolism —> skeletal, neurological, GI, renal toxicity
17
Q
Where is most of lead stores in the body (children)
A
Children: teeth and bones (80-85%). The rest in blood
The rest in blood (5-10%) and soft tissues
18
Q
What effects are associated with lead level of 10ug/ml? 4
A
low IQ, hearing impairments/growth impairments/peripheral nerve function impairment
19
Q
What effects are associated with lead level of 40 ug/ml? 1
A
Decreased Hb synthesis
20
Q
What level of lead is associated with death?
A
150 ug/ml
21
Q
What symptoms are associated with lead level of 100ug/ml? 4
A
Frank anemia
Nephropathy
Encephalopathy
Colic
22
Q
How does lead interfere with haemoglobin synthesis?
A
Inhibits Delta aminovulimic dehydratase and ferrochelatase (haem synthesis)
Inhibits Na-K dependant ATPases in membranes (increases fragility of RBCs)
23
Q
What is diagnostic findings of lead poisoning?
A
Elevated Lead levels plus either
Elevated RBC free protophyrin levels
Or elevated zinc protophyrin levels
24
Q
What kind of anemia is seen in lead poisoning?
A
Microcytic
25
Anemia and basophilic stippling is classically associated with (disease)
Lead poisoning
26
Radiodense lead lines: lead poisoning
27
Radiodense lead lines: lead poisoning
28
What are the neurological effects of lead poisoning: children vs adults?
Children: Brain damage
Adult: peripheral demyelinating neuropathy
29
Lead exposure can lead to which renal problems? 2
Interstitial fibrosis
Decreased uric acid excretion eg saturnine gout
30
What are the types of mercury? 3
1. Organic (methyl mercury)
2. Inorganic (mercuric chloride)
3. Metallic (elemental mercury)
31
What are the main sources of mercury? 2
Contaminated fish (methyl mercury)
Dental amalgrams/workers (metallic)
32
How does mercury cause it's effects?
Similar to lead
33
Where are skin cancers caused by arsenic exposure usually found?
Palms and soles
34
What kinda of cancer is arsenic known to give rise to? 3
Skin
Lung
Bladder
35
What are the effects associated with arsenic exposure? 4
1. Neurologic: sensorimotor neuropathy
2. CVD: HTN and prolonged QT interval
3.skin changes: hyperpigmentation/hyperkeratosis
4. Cancers
36
What are the most toxic forms of arsenic? 3
Arsenic trioxide
Sodium arsenite
Arsenic trichloride
37
How does arsenic cause it's effects (mechanism)
Inhibits oxidative phosphorylation in mitochondria (trivalent arsenic replaces P in ATP)
38
What is nicotine? How does it work?
Alkaloid substance found in tobacco leaves
Binds to nicotinic acetyl choline receptors in brain to release catecholamines--> increase HR, BP, cardiac contractility
39
Smoking: Which components are involved in development of lung cancer? 2
Polycyclic hydrocarbons
Nitrosamines
40
What are the fetal risks of maternal smoking?
Spontaneous abortion
Preterm birth
Intrauterine growth retardation
41
What are the 3 enzymes that metabolize ethanol?
Catalase
Cytochrome P450
Alcohol dehydrogenase
42
A blood alcohol concentration of 80mh/dL is reached after how many SD drinks?
3
43
Where is alcohol dehydrogenase located?
Cytosol of hepatocytes
44
Which cytochrome P450 isotype metabolizes ethanol?
CYP2E1
45
What does acetaldehyde metabolize into?
Acetate/acitic acid
46
Why is fat accumulated in liver of alcoholics?
Alcohol dehydrogenase causes NAD reduction (increase in NADH)
NAD is needed for FA oxidisation in liver and to convert Lactate to pyruvate
47
What is the main nutritional deficiency in alcoholics?
Thiamine B1
48
People who have ALDH2*2 mutation and drink are at risk of which cancer?
Esphageal cancer
49
What is the mechanism of acetaminophen metabolism?
95% goes through Phase II enzymes --> glucoronate/sulfate congugates-->urine excretion
5% goe through CYP2E1--> NAPQI --> lipid peroxidation and protein adducts -->liver necrosis
GSH can detoxify NAPQI
50
What is the treatment of acetaminophen poisoning and it's mechanism?
N-acetylcystiene
Increases GSH levels to metabolize NaPQI
51
What necrosis is seen in liver associated with acetemenophen poisoning?
Centrilobular necrosis
52
Excessive use of oil of wintergreen causes what poisoning?
Salicylate
53
What is the clinical manifestations of acute salicylate poisoning (aspirin)?
Alkalosis (stim of resp centre in medulla)
Development of metabolic acidosis (lactate and pyruvate)
Nausea
Coma
Tinnitus
Headaches
Convulsions
54
Gastric bleeding and petevhial haemorrhages are associated with which poisoning?
Aspirin/salicylate
55
Which form of cocaine is more potent?
Crack (crystal form)
56
What is the mechanism of cocaine?
Prevents reuptake of dopamine in brain (euphoria)
Prevents uptake of epinephrine and norepinephrine and stimulate NA from presynapses
57
What are the symptoms of cocaine use?
1. Cardiac: arrhythmias (Na/Ca/K disruption), coronary vasospasm, dilated carfiomyopathy
2. CNS: seizures and dilated pupils (most common)
3. Perforation of nasal septum (snorters)
4.high temp
5. High BP
58
What are the effects of cocaine in pregnancy?
Decrease blood flow to placenta --> fetal hypoxia and spontaneous abortion
Neurological impairment
59
What is the mechanism that aspirin causes bleeding?
Thromboxane A2 inhibition
60
What is the classic presentation of endocarditis in IV heroin users?
Right sides tricuspid (S. Aureus)
61
Which drug causes feeling of euphoria and then a 'crash'?
Methamphetamine
62
What is the mechanism of methamphetamines?
Releases dopamine in the CNS -->inhibition of presynaptic neurotransmission at corticostriatal synapses-->slowed glutamate release
63
Long term use of this drug causes confusion, pyschosis and paranoia?
Methamphetamine
64
Which illicit drug causes inability to judge time/speed/distance?
Marijuana
65
What is the most common opportunistic infection in burns?
Pseudomonas aeruginosa
66
Classification of burns relies on (burn characteristic)
Depth of burn
67
Burn tissue is what type of necrosis?
Coagulative
68
What are heat cramps?
Excessive electrolyte loss from sweating etc leads to cramping of voluntary muscles
69
What is heat exhaustion?
Brief collapse due to failure of CV system to compensate for hypovolemia. Recovers with hydration
70
What is heat stroke?
Thermoregulatory mechanisms fail, core temp 40: rapid vasodilation and hyperkalemia, arrhythmia and sustained muscle contraction
Can lead rhabdo/muscle necrosis
71
Why does heat stroke lead to rhabdo?
Disruption of ryanodine receptor (RYR1): excessive calcium leakage from SR: muscle contraction stimulated
72
What kind of arrhythmia is associated with electrical injury?
Ventricular arrythmia
73
What is a dangerous characteristic of alternating currents(electricity) in homes?
With contact, can cause tetanic muscle spasms, which would prolong exposure to current and cause chest wall spasm and asphyxia
74
What are the two types of radiation?
Ionising
Non ionising
75
What is ionising radiation?
Radiation that can displace electrons from the atom
76
What is the definition of ionisation?
Collision of electrons with other molecules released electrons in a reaction cascade
77
What is the definition of Curie (Ci) radiation unit?
Disintegration per second of radioisotope (amount radiation from a source)
78
What is a Gray (Gy) or Rad?
Amount of radiation absorbed by target tissue per unit mass
79
What is Sievert unit (Sv) in radiation?
Equivalent dose
80
What is the Field size concept in radiation?
Smaller area exposed to large amounts of radiation is tolerable.
However bigger areas exposed to small doses of radiation can be fatal
81
Which tissues are more vulnerable to ionising radiation?
Rapidly dividing cells eg gonads, bone marrow, lymphoid tissue, mucosa, GI tract
82
How does ionising radiation cause cell death?
DNA damage get detected by P53: this then leads to cell cycle arrest and apoptosis of DNA damage is too great
83
What is the mechanism of which radiation causes DNA damage?
ROS radiolysis of water
84
What is primary malnutrition?
Missing from diet
85
What is secondary malnutrition?
There is a cause eg GI issues, increased needs, impaired use/storage
86
What is severe acute malnutrition?
Weight for height ratio that is 3 SD below normal range
87
How does Marasmus develop?
Low calories (catabolic muscles, head too large for body)
88
What is the serum albumin of a child with Marasmus?
Normal or slightly low (as visceral protein stores not badly affected)
89
What immunity is affected in Marasmus?
T cell mediated
90
What is the clinical features of kwashiorkor?
Oedema
Weight 60-80% normal (fluid retention)
Muscle mass is spared
Skin/hair hypopigmented 'flaky paint'
91
What causes kwashiorkor?
Low protein relative to calories, hypoalbuminemia
92
What size is the liver of kwashiorkor child?
Enlarged - fatty
93
Why do kwashiorkor child may not respond to milk based diets initially?
Disachiridase deficiency - mucosal atrophy and loss of villi. Decrease mitotic cells in crypts of glands
94
Thymic atrophy is seen more is (nutritional disease)
Kwashiorkor
95
This is seen in bone marrow. DX?
Anorexia nervosa (increased fat deposition in bone marrow)
96
What is the diagnostic finding in blood for anorexia nervosa 3
Low levels of GnRH, LH, FSH
97
How does Leptin regulate appetite?
Leptin binds to receptors in hypothalamus --> stimulation of POMC/CART and inhibit NPY/AgRP
This inhibits appetite
98
Aflatoxin increases risk of which cancer?
Hepatocellular carcinoma
99
What cancers are associated with obesity for both genders? Men? Women?
Both: oesophagus and kidney
Men: colon, thyroid
Women: endometrium, gallbladder
100
How does obesity promote cancer?
1. Too much insulin (IGF-1 is carcinogenic)
2. Steroid hormones: regulates cell growth and diff in tissues
3. Reduced adiponectin secretion: no suppression to proliferation
101
Which component in the retina is sensitive to light (needed for night vision)
Rhodopsin rods
102
What can oxygen toxicity cause to lungs?
Diffuse pulmonary infiltrates
103
What deficiency is pellagra caused by?
Niacin
104
What deficiency do alcoholics have?
Thiamine
105
Symptoms of thiamine deficiency?
Neuropathy
Cardiomyopathy
Wernickes
106
What cancer is at higher risk of developing in women that use oral contraceptives?
Hepatic adenoma
107
What are the 3Ds of pellagra?
Diarrhea
Dermatitis
Dementia
108
Which drug can mimic acute psychosis?
Phencyclidine (PCP)
109
Illicit drug that causes acute pulmonary oedema?
Heroin
110
What kind of rays cause thermal injury?
Infrared rays
111
Where is ethylene glycol found? What disease
Anti freeze
Renal tubular necrosis
112
What is the effect of methanol?
Blindness
CNS depression
Acidosis
113
How does methanol cause blindness?
Toxic metabolites: formaldehyde and acetaldehyde damage the retina
114
What deficiency is seen in Beri Beri
Thiamine
115
Symptoms of Beri beri 2
Cardiac failure
Peripheral oedema
116
What symptom is seen in zinc deficiency?
Haemorrhagic dermatitis
117
Isoniazid can cause which deficiency?
Pyridoxine(B6) - pyridoxine antagonist
118
Atrophic gastritis mainly causes which deficiency?
B12
119
Effects of heroin?
Respiratory depression
Convulsions
Cardiac murmurs (endocarditis)
