Environmental and nutritional pathology Flashcards
Which deficiency causes diarrhoea, dermatitis and dementia?
A Riboflavin
B Vitamin B1
C Niacin
D Pyridoxine
C
Explanation
Remember: Niacin cause 4 “D”s. The fourth D is death.
Extra: Niacin is also known as Vitamin B3 and nicotinic acid. Niacin deficiency is known as Pellagra A deficiency causes the 4 D’s=Diarrhoea, Dermatitis, Dementia, Death. Other features include Casal’s Necklace on the lower neck, hyperpigmentation, skin thickening and inflammation of tongue and mouth.
A deficiency in which of the following can cause heart failure?
A Thiamine
B vitamin D
C Zinc
D Pyridoxine
A
Explanation
Thiamine (vitamin B1) deficiency gives rise to three distinctive syndromes. A polyneuropathy (dry beriberi), a cardiovascular syndrome (wet beriberi) and Wernicke-Korsakoff syndrome. Wet beriberi is associated with vasodilatation, leading to more rapid arterio-venous (AV) shunting of blood, high output cardiac failure and eventually peripheral oedema
Which of the following is not associated with B12 deficiency?
A Microcytic anaemia
B Autoimmune gastritis
C Subacute degeneration of the spinal cord
D Crohn’s disease
A
Explanation
B12 is absorbed in the terminal ileum of the small intestine. Crohn’s disease often affects this part of the intestine causing a lack of B12 absorption. Autoimmune gastritis leads to a deficiency in intrinsic factor which is important for the absorption of B12. This results in pernicious anaemia. Vitamin B12 deficiency causes a subacute combined degeneration of the posterior spinal tracts
Smoking is related to all the following carcinomas, with the exception of?
A Oesophageal
B Lung
C Laryngeal
D Endometrial
D
Explanation
Carcinomas caused by smoking include: Trachea, lung, bronchus, larynx, lip, oral cavity, pharynx, oesophagus, bladder, urinary tract, cervix, pancreas and stomach
Note: Cigarette smoking was found to be significantly associated with a reduced risk of endometrial cancer, especially among postmenopausal women.
Which body cell is the most sensitive to radiation injury?
A Gastric mucosal cells
B Ovarian cells
C Cerebral cells
D Haematopoietic stem cells
D
Explanation
In general tissue/cells with the greatest proliferation capability show the highest sensitivity. In terms of sensitivity for the cell types in this question the order from highest sensitivity to lowest is;
- Lymphohaematopoietic
- Ovarian
- Gastric mucosal
- Cerebral
Effects of total body ionizing radiation
Main site if injury
1-2Sv: lymphocytes, granulocytes
2-10Sv: bone marrow
10-20Sv: small bowel
> 50Sv: brain
Estimated Threshold doses for acute radiation effects on specific organs:
Doses in Sv
Testes 0.15
0.5 Sv: Bone Marrow
0.5 Sv: Skin (reversible effects)
1-2 Sv: Ovary
2.5-6Sv: Skin (temporary hair loss)
3-5 Sv: Testis (Permanent sterility) 3.5 Sv
5 Sv: Lens of eye
Which of the following is not increased by cigarette smoking?
A Pancreatic cancer
B Chronic liver disease
C Oesophageal cancer
D Spontaneous abortion
B
Explanation
Smoking increases the risk of cancer, ischaemic heart disease, cardiac arrest, cerebrovascular disease, arteriosclerosis and chronic respiratory disease.
Currenly smoking has a clear dose-response effect on spontaneous abortion, preterm births & intrauterine growth retardation. Prior smoking has not shown to be a significant predictor for future miscarriages.
In pure iron deficiency anaemia, which of the following options occurs?
A Increased ferritin
B Decreased total iron-binding capacity (TIBC)
C Decreased transferrin saturation
D Decreased platelet count
C
Explanation
In a pure iron deficiency, the total iron binding capacity is high and the serum ferritin is low. There is decreased transferin saturation. There is no effect on the platelets. Iron deficiency is the most common nutritional deficiency in the world. Iron is absorbed in the duodenum and has an increased absorption in the presence of vitamin C. Iron excess can cause pulmonary fibrosis
Regarding electrical injuries, which of the following statements is correct?
A Lightning does not cause thermal injury
B Voltage rather than amperage is the most important factor in electrical injury
C All body compartments conduct electricity
D Death is always associated with extensive burns
C
Explanation
Death resulting from electrical injuries is not always associated with extensive burns (usually). Amperage is very important in the aetiology of injury from electrocution. Lightening can cause thermal injury. All tissues of the body are conductors of electricity but they have differing degrees of resistance. Dry skin is not a good conductor of electricity.
Which of the following options is correct regarding electrical injuries?
A Amperage is not important
B Dry skin is a good electrical conductor
C Massive skin burns may cause death
D All body tissues conduct equally
C
Explanation
Death resulting from electrical injuries is not always associated with extensive burns. Amperage is very important in the aetiology of injury from electrocution. Lightening can cause thermal injury. All tissues of the body are conductors of electricity but they have differing degrees of resistance. Dry skin is not a good conductor of electricity.
Which of the following may be caused by thiamine deficiency?
A Glossitis
B Anaemia
C Rickets
D High output cardiac failure
D
Explanation
Wet beriberi will cause high output cardiac failure. The heart may be mildly affected or be massively dilated resulting in a 4 chamber dilitation. The walls become thin and dilated and a mural thrombus may be generated.
Ricketts is associated with Vit D deficiency
Glossitis is associated with Vit B2 (riboflavin) and B6 (pyridoxine) deficiency. Anaemia is associated with B12 (megaloblastic anaemia), B6 (sideroblastic), folate (megaloblastic), and iron (microcytic) deficiency
Which of the following is not a cause of megaloblastic anaemia?
A Folate deficiency
B Neoplasms
C Epstein-Barr virus (EBV) infection
D Pregnancy
C
Explanation
Megaloblastic anaemias are caused by a vitamin B12 deficiency, folic acid deficiency, or due to unresponsiveness to vitamin B12, or folic acid therapy. Pregnancy, hypothyroidism and disseminated cancer all have an increased requirement for B12
EBV may be associated with acute haemolytic anaemia
Which of the following options occurs In iron deficiency?
A Decreased transferrin saturation
B Macrocytic anaemia
C Decreased total iron binding capacity (TIBC)
D Increased serum ferritin
A
Explanation
In iron deficiency anaemia, there is typically a microcytic, hypochromic anaemia, with decreased serum iron, decreased transferrin saturation, decreased serum ferritin, and increased total iron binding capacity. Both the haemoglobin and haematocrit are low and there is a modest poikilocytosis. Remember that the MCV and the MCHC is also low in iron deficiency anaemia
Heroin overdose can cause all of the following, with the exception of?
A Pulmonary oedema
B Miosis
C Acute myocardial infarction due to vasospasm
D Coma
C
Explanation
Heroin is not a sympathetic stimulant and therefore does not cause vasospasm of the coronary arteries
Heroin is a type of opioid. Opiate overdose presents with triad of - CNS depression, Respiratory depression, Miosis. Pulmonary oedema associated with opiate overdose occurs almost exclusively with heroin, occurring in upto 10% of patients.
Which of the following body tissues is most susceptible to radiation damage?
A Brain
B Lungs
C Lymphohaematopoietic system
D Gastrointestinal tract
C
Explanation
Lymphohaematopoietic tissue/cells display the highest sensitivity to radiation. tissues/cells with the greatest proliferation capability show the highest sensitivity. Gastrointestinal tissue is less sensitive followed by brain.
Which of the following is an anti-oxidant?
A vitamin E
B vitamin B6
C vitamin B12
D vitamin K
A
Explanation
Vitamin E is a major antioxidant. Vitamin K is a cofactor in hepatic carboxylation of procoagulants (factor 2, 7, 9 and 10, proteins C and S) Vitamin B12 is required for normal folate metabolism and DNA synthesis Vitamin B6 (pyridoxine) coenzyme in many intermediary reactions. Vitamins A and C are also antioxidants
Regarding Iron, which of the following statements is false?
A Most is found in myoglobin
B Transferrin is usually 33% saturated
C Most is absorbed in the duodenum
D Absorption is increased by vitamin C
A
Explanation
Most iron is found in haemoglobin. 80% of functional iron is found in Hb; myoglobin and iron containing enzymes such as catalase and the cytochromes contain the rest. Almost all iron absorption occurs in the duodenum in the ferrous (Fe2+) form. Transferrin saturation ranges: men 20-50% and women 15-50%. Vit C enhances iron absorption
Common neurological sequelae of lead poisoning in children include all EXCEPT?
A Low intellectual capacity
B Peripheral neuropathies
C Brain damage
D Behavioural changes
B
Explanation
Children absorb more than 50%of ingested lead (adults <15%). The higher intestinal absorption and the more permeable blood brain barrier create a high susceptibility to brain damage. Subclinical lead poisoning (<10ug/dl) leads to low intellectual capacity, behaviour changes, poor organisation skill and hyperactivity. High levels of lead poisoning lead to encephalopathy and brain damage even death. Peripheral neuropathies predominate in adults and not in children
In the current textbook
A figure shows the main clinical features of lead poisoning in children and adults
Peripheral nerves: demyelination in adults
The subsequent text:
Excess lead is toxic to nervous tissues in adults and children; peripheral neuropathies predominate in adults, whereas central effects are more common in children. The effects of chronic lead exposure in children may be subtle, producing mild dysfunction, including reduced IQ, learning disabilities, and delayed psychomotor development. At higher doses, however, the results can be devastating, taking the form of blindness, psychoses, seizures, coma, and even death. Lead-induced peripheral neuropathies in adults generally remit with the elimination of exposure, but both peripheral nervous system and CNS abnormalities in children usually are irreversible.
Although it appears that peripheral neuropathies can occur in children it is more prevalent in adults
(We are leaving the answer as is)
Regarding protein energy malnutrition (PEM), which of the following statements is CORRECT?
A PEM only occurs in children
B Marasmus results in a fatty liver
C Kwashiorkor is due to loss of the visceral protein compartment stores
D A person with a BMI of <20kg/m2 is considered malnourished
C
Explanation
In developing countries PEM occurs in children (up to 25% of children). In developed countries the elderly and debilitated patients in nursing homes and hospitals are affected. A body mass index of <16kg/m2 is considered malnutrition. An easier way to remember is that a child with a weight of <80% of normal is malnourished. PEM presents in malnourished children as marasmus and kwashiorkor. Marasmus-the somatic protein compartment (skeletal muscles) is affected and Kwashiorkor, the visceral compartment (liver). Marasmus occurs when the weight falls <60% of normal. Somatic protein compartment is lost, this is protective as the visceral compartment is more important for survival is maintained. Therefore serum albumin levels are normal or only slightly depleted. Lipolysis also occurs-to obtain fuel. The patient is emaciated. Immune and vitamin deficiencies and anaemia occurs.
Kwashiorkor occurs when the protein deprivation is greater than the reduction in calorie intake. Basically children weaned too early and then fed an exclusive carbohydrate diet. Severe depletion of the visceral compartment occurs resulting in hypoalbuminaemia giving rise to dependant oedema. Loss of weight is masked by the increased fluid retention. There is relative sparing of muscle mass and subcutaneous fat. A fatty liver occurs. Skin changes include area of hypopigmentation and desquamation.
Vitamin B12 deficiency is associated with the following disorders EXCEPT?
A Crohn’s disease
B Autoimmune gastritis
C Fish tape worm infestations
D Left hemicolectomy
D
Explanation
Vitamin B12 deficiency is associated with disorders other than pernicious anaemia. Most of these impair absorption of the vitamin. E.g. malabsorption states, diffuse intestinal disease (lymphoma, systemic sclerosis), ileal resection (including as part of a right hemicolectomy), ileitis (Crohn’s disease), competitive parasitic uptake, fish tapeworm infestation, and bacterial overgrowth in blind loops and diverticula of bowel. Increased demand for B12 can also result in a deficiency such as: pregnancy, hyperthyroidism, disseminated cancer, chronic infection
Pernicious anaemia- a specific cause of vitamin B12 deficiency- is a specific form of megaloblastic anaemia caused by autoimmune gastritis (also atrophic gastritis) and an attendant failure of intrinsic factor production, resulting in failure to absorb vitamin B12
Which vitamin deficiency causes the 3 Ds?
A Vitamin A
B Vitamin B1
C Riboflavin
D Niacin
D
Explanation
Niacin-vitamin B3-deficincey causes Pellagra which consists of the following symptoms: diarrhoea, dermatitis and dementia. There is a fourth “D”-death
Pellagra (rough skin) is a disease caused by a lack of the vitamin niacin (vitamin B3). Symptoms include inflamed skin, diarrhea, dementia and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over time affected skin may become darker, stiff, begin to peel, or bleed.
There are two main types of pellagra, primary and secondary. Primary pellagra is due to a diet that does not contain enough niacin and tryptophan. Secondary pellagra is due to a poor ability to use the niacin within the diet. This can occur because of alcoholism, long term diarrhea, carcinoid syndrome and Hartnup disease, and several medications such as isoniazid. Diagnosis is typically based on symptoms and may be assisted by urine testing.
Source: Wikipedia
A 25 male is brought into the ED with a GCS of 3. He has a cherry-red skin colour. What is the most likely poisoning?
A Cardon monoxide
B Nitric oxide
C Carbon dioxide
D Cyanide
A
Explanation
Hemoglobin is a tetramer with four oxygen binding sites. The binding of carbon monoxide at one of these sites increases the oxygen affinity of the remaining three sites, which causes the hemoglobin molecule to retain oxygen that would otherwise be delivered to the tissue. This situation is described as carbon monoxide shifting the oxygen dissociation curve to the left. Because of the increased affinity between hemoglobin and oxygen during carbon monoxide poisoning, little oxygen will actually be released in the tissues. This causes hypoxic tissue injury. Hemoglobin acquires a bright red color when converted into carboxyhemoglobin, so poisoned cadavers and even commercial meats treated with carbon monoxide acquire an unnatural reddish hue.
From the TB: acute poisoning of CO is marked by a characteristic generalised cherry-red colour of the skin and mucous membranes
Note: UptoDate: Cyanide poisoning-Skin – Flushing (cherry-red colour), cyanosis (late finding), irritant dermatitis (itching, erythema, oedema, vesicles resulting from skin exposure)
I think CO is a better answer than cyanide causing the cherry red colour.
A 22-year-old man suffers 50% body surface area burns. Which microorganism is he at most at risk of infection from?
A S. aureus
B Pseudomonas aeruginosa
C S. epidermidis
D E. Coli
B
Explanation
The burn site is ideal for growth of microorganisms. The serum and debris provide nutrients, and burn injury compromises blood flow, blocking effective inflammatory responses. The most common offender is the opportunistic Pseudomonas aeruginosa, but antibiotic-resistant strains of other common hospital-acquired bacteria, such as S aureus, and fungi, particularly Candida species, may also be involved.
What is the leading cause of premature death and morbidity worldwide?
A Malnutrition
B HIV/AIDS
C Diarrhoeal diseases
D Cardiovascular disease
C
Explanation
In the current text book Robbin’s (9th): “Undernutrition is the single leading global cause of health loss (defined as morbidity and premature death” whereas IHD and cerebrovascular disease are the leading causes of death in developed countries.
The top 10 causes of death according to the WHO website:
In 2019, the top 10 causes of death accounted for 55% of the 55.4 million deaths worldwide.
The top global causes of death, in order of total number of lives lost, are associated with three broad topics: cardiovascular (ischaemic heart disease, stroke), respiratory (chronic obstructive pulmonary disease, lower respiratory infections) and neonatal conditions – which include birth asphyxia and birth trauma, neonatal sepsis and infections, and preterm birth complications.
Causes of death can be grouped into three categories: communicable (infectious and parasitic diseases and maternal, perinatal and nutritional conditions), noncommunicable (chronic) and injuries.
The leading cause of Death GLOBALLY is IHD followed by stroke.
The leading cause of death in:
Low income countries: neonatal conditions
Lower, middle and upper income countries: IHD
Overall thoughts: One should follow the textbook; therefore, malnutrition should be the right answer. Apologies to the users, we are not sure what the right answer should be.
Extras: from a user
The question asks leading cause of premature death and MORBIDITY worldwide. This is measured in DALYs, not just Mortality. The WHO Report from 2000-2019 indicates that the leading cause is Neonatal conditions ( 8%) followed by IHD (7.1%). Given that Neonatal conditions are not listed as an answer (birth trauma etc.) and “Cardiovascular disease” covers Rheumatic heart disease, Hypertensive heart disease as well as IHD; Malnutrition could be the correct answer. From Robbins “Undernutrition is the single leading global cause of health loss (defined as morbidity and premature death). It is estimated that about one third of the disease burden in developing countries is, directly or indirectly, due to poor general nutrition or deficiencies in specific nutrients that increase the risk of infections.”
A concerned mother brings her 2 week old daughter to the emergency department due to yellow skin. She is otherwise well. Blood tests reveal an unconjugated hyperbilirubinaemia. What is the likely cause?
A Impaired conjugation
B Impaired excretion
C Impaired hepatocellular uptake
D Deficienct gastrointestinal enzymes
A
Explanation
Physiological jaundice of the newborn presents with jaundice at 1-14 days in an otherwise well infant. Because hepatic metabolic machinery does not mature until approximately 2 weeks of age, almost every newborn develops transient, mild unconjugated hyperbilirubinaemia. This can be exacerbated by breast-feeding due to bilirubin-deconjugating enzymes in breast milk.
Opthalmoplegia and neurological dysfunction in an alcoholic is most likely to response to supplementation with which vitamin?
A B3
B B12
C B6
D B1
B
Explanation
Wernicke encephalopathy presents with psychotic symptoms and ophthalmoplegia and is a complication of thiamine deficiency in alcoholics.
Thyroid disease is now relatively uncommon in the developed world due to addition of which of the following substances to table salt?
A Iodide
B Calcium
C Potassium
D Sodium
A
Which tissue is most damaged with radiation dose of 1-2Sv?
A Lymphoid
B Cardiovascular
C Brain
D Gastrointestinal
A
Explanation
Main site of injury for 1-2Sv is lymphocytes (Table 7-8) – moderate granulocytopaenia, lymphopaenia.
2-10Sv associated with injury to bone marrow.
10-20Sv with small bowel injury.
>50Sv associated with brain injury
Which tissue is most susceptible to radiation-induced cancer?
A Breast
B Thyroid
C GIT
D Lymphoid
D
Explanation
The hematopoietic and lymphoid systems are extremely susceptible to radiation injury and deserve special mention
Increased incidence of leukaemias and solid tumours in several organs (e.g. thyroid, breast, and lungs) observed after Hiroshima, Nagasaki, Marshall Islands etc. ‘Second cancers’ include acute myeloid leukaemia and myelodysplastic syndrome (as well as solid tumours)
Extra: Radiation exposure can cause cancer in any living tissue, but high-dose whole-body external exposure is most closely associated with leukemia, reflecting the high radiosensitivity of bone marrow. (Wikipedia)
Which tissue is most susceptible to radiation-induced cancer?
A Lymphoid
B Breast
C Brain
D Thyroid
A
Explanation
The level of radiation required to increase the risk of cancer development is difficult to determine, but there is little doubt that acute or prolonged exposures that result in doses of greater than 100mSv cause serious consequences, including cancer. Proof- increased incidence of leukaemia’s and solid tumours in several organs (thyroid, breast and lungs) in survivor of the atomic bombings of Hiroshima and Nagasaki. High number of thyroid cancers in the Chernobyl accident. High incident of leukaemia’s in the Marshall island nuclear fallout.
Extra:
For most of these cancers, the risk was highest for those exposed as children, and was lower as the age at exposure increased. Those exposed while still in the womb (in utero) had lower risks than those exposed during childhood.
Higher radiation exposure was linked to higher risk of cancer, but even low amounts of radiation were linked to an increased risk of getting and dying from cancer. There was no clear cut-off for safe radiation exposure.
These cancers took years to develop, but some cancers appeared sooner than others. Deaths from leukemia went up about 2 to 3 years after exposure, with the number of cases peaking after about 10 years and going down after that. Solid tumors took longer to develop. For example, excess deaths from lung cancer began to be seen about 20 years after exposure.
What do the studies show?
Atomic bomb survivors
Much of what we know about cancer risks from radiation is based on studies of the survivors of the atomic bombs in Nagasaki and Hiroshima. These people had higher risks of some, but not all cancers. Studies have found an increased risk of the following cancers (from higher to lower risk):
Most types of leukemia (although not chronic lymphocytic leukemia)
Multiple myeloma
Thyroid cancer
Bladder cancer
Breast cancer
Lung cancer
Ovarian cancer
Colon cancer (but not rectal cancer)
Oesophageal cancer
Stomach cancer
Liver cancer
Lymphoma
Skin cancer (besides melanoma)
For most of these cancers, the risk was highest for those exposed as children, and was lower as the age at exposure increased. Those exposed while still in the womb (in utero) had lower risks than those exposed during childhood.
Higher radiation exposure was linked to higher risk of cancer, but even low amounts of radiation were linked to an increased risk of getting and dying from cancer. There was no clear cut-off for safe radiation exposure.
These cancers took years to develop, but some cancers appeared sooner than others. Deaths from leukemia went up about 2 to 3 years after exposure, with the number of cases peaking after about 10 years and going down after that. Solid tumors took longer to develop. For example, excess deaths from lung cancer began to be seen about 20 years after exposure.
Source: American cancer society
