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Kofi: Pure clinical conditions > MEH conditions > Flashcards

MEH conditions Flashcards

1
Q

What is the effect of G6DP deficiency?

A
  • Reduced activity of the enzyme so low level of NADPH. NADPH is required for reduction of oxidised glutathione back to active reduced form
  • Reduced glutathione is needed for oxidative damage protection
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2
Q

Why are red blood cells particularly affected by G6DPH deficiency?

A

The only source of NADPH they have is from the G6DP reaction. This results in haemoglobin cross linkage due to oxidative damage and formation of Heinz bodies.

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3
Q

What is the cause of Galactosaemia?

A

Lack of Galactokinase enzyme and galactose-1-phosphate Uridyl transferase enzyme (more common).

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4
Q

What is galactosaemia?

A
  • Lack of galactokinase results in accumulation of galactose
  • Lack of Galactose-1-phosphate uridyl transferase enzyme and UDP epimerise enzyme results in increase in Glalactose and Galactose-1-Phosphate.
  • Accumulation of galactose results in aldose reductase reducing it to galactitol and depleting NADPH.
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5
Q

What is the effect of galactosaemia?

A
  • In the eye it causes cataracts due to lens structure damage via cross linking of proteins by disulphide bonds. There also could be non enzymatic glycosylation of the lens protein due to high lactose which contribute to cataracts
  • There could be increased intra-occular pressure applied on the eye due to accumulation of galactose and galacticol therefore causes glaucoma
  • Damage to liver, brain, kidney due to galactose 1 phosphate accumulation
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6
Q

What cause essential fructosuria?

A

Fructose kinase missing

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7
Q

What causes fructose intolerance?

A

Aldolase missing. The fructose 1 phosphate accumulates in the liver leading to liver damage

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8
Q

What smell is present on the breath of untreated type 1 diabetic patients?

A

Smell of acetone.(nail polish remover)

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9
Q

What is the cause of ketoacidosis?

A

High concentrations of acetoacetate and beta hydroxybutyrate.

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10
Q

What is the mechanism of action of Statin?

A

They inhibit HMG-CoA reductase so less cholesterol is synthesised.

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11
Q

What is the effect of excessive alcohol consumption on the liver?

A

-Decrease in NAD+/NADH ratio and the increased availability of acetyl CoA lead to increased synthesis of fatty acids and ketone bodies.
-Newly synthesised fatty acids are converted to triacylglycerols
-Lack of lipoprotein synthesis causes a fatty liver
In some cases ketone body production is sufficient to cause ketoacidosis

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12
Q

What is used as an adjunct in treatment for alcohol dependance?

A

Disulfiram. Causes accumulation in acetaldehyde and causes a hangover.

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13
Q

What can damage to hepatocytes lead to?

A
  • Hyperbilirubinaemia due to reduction in the liver capacity to take up conjugate bilirubin which may produce jaundice
  • Oedema due to low serum albumin
  • Decreased in capacity to produce urea so this leads to hyperammonaemia and increased level of glutamine
  • Decreased amounts of clotting factors lead to increase in blood clotting time
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14
Q

What is chronic pancreatitis?

A

Inflammation of the pancreas due to chronic heavy alcohol consumption. Symptoms are

  • constant pain in the upper abdomen that radiate to the back
  • weight loss due to malabsorption causes by insufficient enzyme production
  • if the beta pancreatic cells are damaged, lack of insulin leads to hypoglycaemia and glycosuria
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15
Q

What is produced when a toxic dose of paracetamol is ingested?

A

NAPQI which is a strong oxidising agent and is conjugated with glutathione depleting its levels. This causes oxidative stress

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16
Q

What the treatment for paracetamol overdose?

A

Acetylcysteine (within 8 hours) to replenish the glutathione levels so liver can safely metabolise the NAPQI. Beyond 8 hours, death as a result of liver failure may be inevitable

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17
Q

What is the cause and symptoms of phenylketonuria?

A

Defective phenylalanine hydroxylase enzyme which so phenylalanine accumulates in tissues and blood. It is metabolised in other pathways which causes the production of phenylpyruvate which is excreted in the urine.
If untreated results in inhibition of brain development due to inhibitor of pyruvate uptake into mitochondria by phenylpyruvate.

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18
Q

How is phenylketonuria diagnosed?

A

Phenylketone detected in the urine
Measurement of the blood phenylalanine concetration
At birth the Heel prick test

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19
Q

What is homocystinuria?

A

Rare autosomal recessive defect in methionine metabolism in which the 1 is caused by a deficiency in cystathionine B-synthase (CBS) enzyme. Levels of homocysteine increase in blood and some of this is converted to methionine. Increase in plasma levels of homocysteine can cause disorders of connective tissue, muscle, CNS and cardiovascular system. Detected by high levels of methionine and homocysteine in plasma and homocysteine in urine.

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20
Q

How does homocystunuria present in children and why is this important?

A

Similar symptoms to marfan’s syndrome so can be misdiagnosed. The fibrillin-1 protein structure is affected.

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21
Q

What is refeeding syndrome?

A

When nutritional support is given to severely malnourished patient, due to the enzyme in the urea cycle not being induced to handle the amount of nitrogen being introduced, it can result in a toxic ammonia concentration which can cause death. Therefore it is important to gradually raise to their full needs over a week.

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22
Q

What does defect in one of the enzyme in the urea cycle result in?

A

-Hyperammonaemia
-Accumulation and/or excretion of particular urea cycle intermediate
Symptoms
-Irrittability
-Vomiting
-Lethargy
-Mental retardation
-Seizures
-Coma
-Death

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23
Q

What is the treatment for defect in enzyme in the urea cycle?

A

Low protein diets or a diet in which the keto acids of the essential amino acids are used to replace the amino acids themselves which used NH4+ so lowers it concentration

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24
Q

What is Von gierke’s disease?

A

Glucose-6-phosphatase deficiency

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25
Q

What is McArdle disease?

A

Muscle glycogen phosphorylase deficiency

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26
Q

What is the effect of defect of enzymes in the glycogen cycle?

A 
Increased or decreased amounts of glycogen which may cause:
-Fasting Hypoglycaemia
-Tissue damage if excessive storage
-Poor exercise tolerance
-Glycogen structure may be abnormal
Usually liver and/or muscle affected
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27
Q

What can disorder in lipoprotein metabolism lead to?

A

Atherosclerosis and Coronary artery disease

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28
Q

What causes unstable lipoproteins of abnormal structure?

A

Deficiency in the LCAT enzyme. Less conversion of cholesterol to cholesterol ester using fatty acid derived from lecithin. Failure in the lipid transport process.

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29
Q

Why are LDL particles more likely to lead to formation of atherosclerotic plaques?

A

Longer half life so therefore increased chance of oxidative damage

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30
Q

What is familial hypercholesterolaemia?

A

Absence (Homozygous) or deficiency (heterozygous) of functional LDL receptors. The condition is characterised by elevated levels of LDL and cholesterol in plasma. Extensive atherosclerosis in homozygous sufferers early in life and later in life for heterozygous.

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31
Q

What is the cause of type 1 hyperlipoproteinaemia?

A

Caused by defective lipoprotein lipase. Chylomicrons in fasting plasma.

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32
Q

What is the cause of type 2a hyperlipoproteinaemia?

A

Caused by defective LDL receptor.

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33
Q

Which type of hyperlipoproteinaemia are linked with coronary heart disease?

A

Type 2a, 2b, 3, 4, 5

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34
Q

What is the cause of hyperlipoproteinaemia 3?

A

Defective apoprotein E. Raised IDL and chylomicron remnants.

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35
Q

What is the cause of hyperlipoproteinaemia 5?

A

Raised chylomicrons and VLDL in fasting plasma.

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36
Q

What are the clinical sign of hypercholesterolaemia?

A
  • Xanthelasma
  • Tendon xanthoma
  • Corneal Arcus
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37
Q

What is the result of a splenectomy?

A
  • Increased risk of infection by encapsulated bacteria

- Increased risk of sepsis

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38
Q

What can cause hereditary spherocytosis?

A

Gene mutations in membrane associated proteins. (ankyrin, band 3, protein 4.2, spectrin)

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39
Q

What is iron deficiency ?

A

It is a symptom and not a diagnosis. Clinicians must treat the underlying cause which can be:

  • excessive bleeding
  • pregnancy
  • insufficient intake or poor absorption
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40
Q

What is hereditary hemochromatosis?

A

An autosomal recessive disorder characterised by excessive absorption of dietary iron. Iron accumulates in tissues and organs disrupting their normal function as there is no system for iron secretion. Defect is in HFE gene which normally binds to transferrin receptor to reduce its affinity for iron-bound transferrin.

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41
Q

What is the presentation in a patient with hereditary hemochromatosis?

A
  • Cirrhosis
  • Adrenal insufficiency
  • Heart failure
  • Arthritis
  • Diabetes
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42
Q

What is the treatment for hereditary hemochrombtosis?

A

Therapeutic phlebotomy to remove excess iron

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43
Q

What are the symptoms of acute onset anaemia?

A
  • Fatigue
  • Dyspnoea
  • Palpitations
  • Headache
  • Angina and intermittent claudication in older patients

Clinical signs are

  • Pallor
  • Tachycardia
  • Systolic murmur
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44
Q

Why might anaemia develop?

A
  • Abnormal erythropoiesis (chemotherapy, radiating parvovirus, autoimmunity, chronic kidney disease)
  • Abnormal haemoglobin synthesis (iron deficiency)
  • Chronic disease (macrophages reduce RBC lifespan, IL-6 increase production of hepcidin)
  • Globin gene mutation (Thalassaemia, sickle cell anaemia)
  • Deficiencies in building blocks for DNA synthesis (folate, Vitamin B12)
  • Deficiency in red cell metabolism (G6DPH deficiency, Pyruvate kinase defciency)
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45
Q

What are myeloproliferative neoplasms?

A

A group of diseases of the bone marrow in which excess cells are produced

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46
Q

What is the common molecular pathogenesis of myeloproliferative neoplasms?

A

Mutation of the gene coding for the tyrosine kinase Janus Kinase 2(JAK2)

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47
Q

What is thrombocythaemia?

A

Excess production of platelets by megakaryocytes

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48
Q

What is polycythaemia vera and its clinical features?

A

Characterised by overproduction of red blood cells.

Clinical features are

  • Thrombosis
  • Haemorrhage
  • Burning pain in the hands and feet
  • Pruritis
  • Splenic discomfort, splenomegaly
  • Gout
  • Arthritis
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49
Q

What is myelofibrosis?

A

Characterised by replacement of the haematopoietic tissue by connective tissue leading to impairment of the generation of all blood cells.

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50
Q

What is the treatment of polycythaemia vera?

A
  • Phlebotomy to maintain haematocrit below 45%

- Aspirin is due to its anti-platelet effects may be prescribed unless contraindicated

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51
Q

What are the causes of polycythaemia?

A
  • Increase in number of erythrocytes

- Decrease in the plasma volume

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52
Q

What is the cause of acromegaly?

A

-Excess growth hormone secretion

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53
Q

What are the symptoms of acromegaly in an adult?

A

Gradual change in features over years

  • Broad nose
  • Coarse facial features
  • Thick lips
  • Prominent supraorbital ridge
  • Enlargement of hands and feet
  • Greasy skin with excessive sweating
  • Deepening of the voice
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54
Q

What are the long term complications of acromegaly?

A
  • Premature cardiovascular death
  • Increased risk of colonic tumours
  • Increased risk of thyroid cancer
  • Hypertension and diabetes mellitus
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55
Q

What does excessive secretion of growth hormone in childhood lead to?

A

Gigantism

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56
Q

What is the test for excessive growth hormone secretion?

A

-Oral glucose tolerance test with GH response
-Failure to suppress GH
-Elevated IGF-1 level
-

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57
Q

What are 3 types of treatment for patient with acromegaly?

A
  • Surgery to remove adenoma
  • Radiation therapy
  • Drug therapy (Pegvisomant, Carbegoline)
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58
Q

What are the structure surrounding the pituitary gland?

you don’t to remember according to lecturer but appreciate the effect of the tumour

A

Optic chasm(vision) - Superior
Oculomotor nerve and trochlear nerve (eye movement) - Lateral
Ophthalmic nerve and Maxillary nerve (Pain) - Medial
Internal carotid artery (blood supply) and Abducens nerve (lateral eye movement) - twist around it

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59
Q

What is the effect of growth of the tumour in the pituitary?

A
  • Visual field loss
  • Double vision and pain
  • Eye compressive problems
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60
Q

What is the cause of hypopituitarism?

A 
Commonly as a result of a pituitary adenoma
Rarer causes are:
-Radiation therapy
-Inflammatory disease
-Head injury
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61
Q

What is the deficiency of all anterior pituitary hormones called? Which hormones are affected first?

A

Panhypopituitarism

  • GH
  • LH/FSH
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62
Q

How is deficiency in growth hormone tested?

A

-Check response to hypoglycaemic stress

Growth hormone goes up in hypoglycaemia

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63
Q

How is an excess in GH tested?

A

-Suppress with glucose load

Growth hormone should decrease

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64
Q

What the indications of Gonadotropin deficiency?

A
  • Lack of libido
  • Infertility
  • Oligomenorrhea or Amenorrhea in women of reproductive age
  • Impotence in men
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65
Q

What is the classical change in appearance for Cushing disease?

A
  • Round pink face (moon shaped)
  • Abdominal obesity
  • Skinny and weak arms and legs
  • Thin skin and easy bruising
  • Red/Purple stretch marks on abdomen
  • High blood pressure
  • Hyperglycaemia
  • Osteoporosis
  • Buffalo hump
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66
Q

What is the cause of diabetes insipidus?

A

Lack of vasopressin(ADH) so aqua porin channels are not opened so water isn’t reabsorbed so increased urine.
Can be cranial (pituitary) or nephrogenic (kidney)

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67
Q

What are the consequence of untreated Diabetes insipidus?

A
  • Severe dehydration

- Very high sodium levels - reduced consciousness, coma and death

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68
Q

What is a prolactinoma?

A

Prolactin secreting tumour . The larger the tumour the higher the prolactin

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69
Q

What does hyperprolactinaemia in women cause?

A
  • Menstrual disturbance
  • Fertility problems
  • Galactorrhea
  • Hard breast tissue
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70
Q

What does hyperprolactinaemia in men cause?

A
  • Usually presented later due to lack of periods
  • Usually larger tumour
  • Symptoms of low testosterone are not specific (Loss of sex drive, erectile dysfunction)
  • May present with mass symptoms such as visual loss
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71
Q

Why is hypogonadism caused by the hyperprolactinaemia?

A

Higher level of dopamine (PIH) in the hypothalamus which inhibits GnRH secretion from the hypothalamus therefore FSH and LH secretion from anterior pituitary.

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72
Q

What is the treatment for prolactinoma?

A

Drugs such as Cabergoline and Bromocriptine. Not treated with surgery.

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73
Q

What are the causes of hyperprolactinaemia?

A
  • Pregnancy
  • Suckling
  • Stress
  • Exercise
  • Antipsychotics
  • Antidepressants
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74
Q

What situation of hyperprolactinaemia requires surgery?

A

Rare case where the prolactin increases due to disinhibition by dopamine as a result of a pituitary tumour blocking the secretion of dopamine. This may also inactivate ACTH or LH/FSH

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75
Q

What is marasmus?

A

A type of protein energy malnutrition common in children under 5.

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76
Q

What are the indications of marasmus?

A
  • Emaciated with obvious signs of muscle wasting
  • Loss of body fat with no oedema
  • Hair is thin and dry.
  • Diarrhoea is common
  • Anaemia may be present
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77
Q

What is kwashiorkor?

A

A condition commonly seen in children who have a diet with low protein content and some carbohydrates. Typically with occurs in young children

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78
Q

How does kwashiorkor result in oedema?

A

There is insufficient amino acid for the liver to make a normal level of blood proteins such as albumin so the plasma oncotic pressure drops increasing net flow of fluid out of the vessel into the interstitium.

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79
Q

What are the signs of kwashiorkor?

A
  • Apathetic
  • Lethargic
  • Anorexic
  • Generalised oedema
  • Abdomen distended due to hepatomegaly or ascites
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80
Q

What are the presentations of Type 1 diabetes?

A

Symptoms

  • Polyuria : excess urine production. Loss of isosmotic reabsorption at the end of the proximal nephron so extra glucose remain in the tubule which means less water is also reabsorbed into blood so excess urine.
  • Polydipsia : due to excess water loss
  • Weight loss : fat and protein metabolism

Patient

  • Usually young
  • Presence of ketones
  • Elevated venous plasma glucose
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81
Q

How can type 1 diabetes be diagnosed?

A

-Measured by plasma glucose levels. It is elevated due to lack of glucose.

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82
Q

What can type 1 diabetes cause if not dealt with urgently?

A

Diabetic ketoacidosis which is a life threatening crisis

83
Q

What is glucosuria?

A

Glucose in the urine. Result of diabetes

84
Q

What are the presentations of ketoacidosis?

A
  • Prostration
  • Hyperventilation
  • Nausea
  • Vomiting
  • Dehydration
  • Abdominal pain
85
Q

What is it important to test for in a diabetic patient?

A

Ketones in the urine to assess diabetes control

86
Q

What is the presentation of type 2 diabetes in a patient ?

A
  • Polyuria : excess urine production. Loss of isosmotic reabsorption at the end of the proximal nephron so extra glucose remain in the tubule which means less water is also reabsorbed into blood so excess urine.
  • Thirst : due to excess water loss
  • Weight loss : fat and protein metabolism
  • Lack of energy
  • Persistent infections
  • Particularly thrush infections of genitalia
  • Foot infections
  • Slow healing minor skin damage
  • Visual problems
87
Q

How can type 1 diabetes be cured?

A

It cannot. It has to be managed for the rest of the patients life with insulin injections. Increased dose with infections or trauma. This is done along an appropriate diet and exercise.

88
Q

How can type 2 diabetes be managed?

A
  • Managed by diet or oral hypoglycaemic drugs such as sulphonylureas that increase insulin release from the remain B-cells and reduce insulin resistance and particularly the suphonylurea called metformin that reaches gluconeogenesis
  • Done alongside exercise and diet
89
Q

What are the metabolic consequences of hyperglycaemia?

A
  • Uptake of glucose into cells of tissues such as peripheral nerves, eye, kidney is determined by extracellular glucose concentration and not insulin dependant
  • In hyperglycaemia, the intracellular concentration of glucose in these tissues increased. Glucose is metabolised via the aldose reductase enzyme to sorbitol
  • Reaction depletes cellular NADPH and leads to increased disulphide bond formation in cellular proteins altering their structure and function.
  • Accumulation of sorbitol causes osmotic damage to cells
90
Q

How does persistent hyperglycaemia affect plasma proteins?

A

They undergo glycation that leads to disturbances in the proteins function.

91
Q

What is the percentage of glycated haemoglobin a good indicator of?

A

Percentage of Glycated haemoglobin is a good indicator of how effective blood glucose control has been.

92
Q

What does having over 10% of haemoglobin glycated indicate in a diabetic?

A

Poor controlled diabetes

93
Q

What are the macroscopic complications of long term diabetes?

A
  • Increased risk of stroke
  • Increased risk of myocardial infarction
  • Poor circulation to the periphery
94
Q

What are the microscopic complications of long term diabetes?

A
  • Diabetic eye disease
  • Diabetic kidney disease
  • Diabetic neuropathy
  • Diabetic feet
95
Q

What is the cause of diabetic eye disease?

A
  • Due to diabetic retinopathy.
  • Damage to blood vessels into the retina can lead to blindness.
  • Damaged blood vessels may leak and form protein exudates in the retina or can burst to lead to bleeding into the eye. In addition new blood vessels may form which are weak and easily bleed
  • Also arise from changes to lens due to osmotic effects of glucose and possibly cataracts
96
Q

What is diabetic kidney disease?

A
  • Kidney is affected by damage to glomeruli.
  • Poor blood supply because of changes in kidney blood vessels
  • Damage from infections the urinary tract which are more common in diabetics.
97
Q

What is diabetic neuropathy?

A

Damage to peripheral nerves producing a variety of effects

  • Change or loss of sensation
  • Changes due to alteration in the function of the autonomic nervous system.
98
Q

What is diabetic feet?

A

-Poor blood supply, damage to nerves and increased risk of infection all conspire to make the feet of the diabetics particularly vulnerable.

99
Q

What is type 1 diabetes?

A
  • Characterised by progressive loss of all or most of the pancreatic beta cells. It is rapidly fatal if not treated and must be treated with insulin. It is autoimmune
  • Commonest type in young
100
Q

What is type 2 diabetes?

A
  • Affects a large number of usually older individuals
  • Characterised by slow progressive loss of all or most of the pancreatic beta cells along with disorder of insulin secretion and tissue resistance to insulin. May be present for a long time before diagnosed
101
Q

What can measurement of C-peptide be used for?

A

It is used to monitor any endogenous insulin secretion as it is released in equimolar amount with insulin.

102
Q

What are the actions of aldosterone?

A
  • Acts on distal tubules and collecting ducts of nephrons in the kidney causing reababsorpton of Na+ and water and secretion of K+ into tubular lumen. Upregulates the expression of the basolateral Na+/K+ pump.
  • Upregulates the ENaCs in the collecting duct and also colon promoting Na+ absorption
103
Q

Why should time always be recorded when taking cortisol measurements?

A

-Cortisol levels varies during the day from a peak at a 7am and a trough at 7pm so the time at which the measurement is taken should be repeated at the same time of day

104
Q

What is the effect of over secretion AcTH on the adrenal glands?

A

Hyperplasia and over-production of cortisol

105
Q

What are the clinical effects of excess cortisol secretion and why does it occur?

A

Cushing’s syndrome. This is due to

  • Increased activity of the adrenal cortex due to primary cortisol producing adrenal adenoma
  • Disorders in the secretion of ACTH caused by a pituitary adenoma (Cushing’s disease) or in rare cases ectopic secretion of ACTH from a tumour at a site remote from the pituitary.
106
Q

What are the sign and symptoms of excess cortisol secretion?

A

-Hyperglycaemia (polyuria, polydipsia)
Increased muscle proteolysis and hepatic gluconeogenesis.

-Muscle weakness and thin arms and legs
Increased muscle proteolysis leads to wasting of wasting of proximal muscle and producing thin arms and legs and muscle weakness

-Buffalo hump
-Abdominal obesity
-Plethoric moon shaped face
-Acute weight gain
Increased lipogenesis in adipose use leading to deposition of fat in abdomen , neck and face

-Purple striae on the lower abdomen, upper arms and thigh
Due to catabolic effects on protein structure in the skin and leading to easy bruising because of thinning of skin and subcutaneous tissue

-Acne and bacterial infection
Immuno-supppresive and anti-inflammatory and anti allergic reactions of cortisol

-Back pain and collapse of ribs
Due to osteoporosis caused by disturbances in calcium metabolism and loss of bone matrix protein

-Hypertension
Mineralocorticoid defects of excess cortisol leads to sodium and fluid retention

107
Q

What is the difference between Cushing’s disease and Cushing’s syndrome?

A
  • Cushing’s syndrome refers to generalised symptoms resulting from chronic excessive exposure to cortisol
  • Cushing’s disease refers to the specific case of benign ACTH secreting pituitary adenoma.
108
Q

What is the common cause of Cushing’s syndrome?

A

Patients receiving long term treatment with glucocorticoids from various chronic inflammatory conditions. Examples include Hydrocortisone, Dexamethasone and Prednisolone

109
Q

What are the clinical effects of too little cortisol and what are the possible causes?

A

Decreased activity of the adrenal cortex (Addison’s disease) may be due to

  • Disease of adrenal cortex such as auto immune destruction reduces glucocorticoids and mineral corticoids
  • Disorders in pituitary or hypothalamus that lead to decreased secretion of ACTH or CRF - affects glucocorticoids
110
Q

What are the symptoms of Addison’s disease?

A
  • Lethargy
  • Extreme muscular weakness
  • Extreme dehydration
  • Anorexia
  • Vague abdominal pain
  • Weight loss and occasional dizziness
  • Increased skin pigmentation - Due to increased in ACTH as well as other products of POMC which stimulates melanocytes to produce melanin
  • Decreased blood pressure due to sodium and fluid depletion. Postural hypotension
  • Hypoglycaemic - lack of glucocorticoid
111
Q

What is Addison’s crisis?

A

An acute life threatening emergency due to adrenal insufficiency. Precipitated by

  • Sever stress
  • Salt depravation
  • Infection
  • Trauma
  • Cold exposure
  • Over exertion
  • Abrupt steroid drug withdrawal
112
Q

What is Conn’s syndrome?

A

Aldosterone secreting adrenal adenoma. Can be caused by one or both adrenal glands.

113
Q

What are the signs of hyperaldosteronism?

A
  • Hypertension at young age
  • Hypokalaemia
  • Stroke
  • Hypernatraemia
  • Left ventricular hypertrophy
114
Q

What can be used as a marker for primary hyperaldosteronism?

A
  • High aldosterone with decreasing renin

- High aldosterone:Renin ratio

115
Q

What is congenital adrenal hyperplasia?

A

An autosomal recessive disorder causing adrenal crisis and ambiguous genitalia.
Caused by a block in adrenal cortex pathway due to an enzyme defect and result in increased secretion of androgens

116
Q

What is the effect of the lack of enzyme in CAH?

A
  • Low cortisol and aldosterone

- High male hormone

117
Q

What is the presentation in CAH?

A
  • Hypotension
  • Hyponatraemia
  • Hyperkalaemia
  • Hypoglycaemia
  • Virilisation
118
Q

What are the types of primary hyperaldosteronism?

A
  • Aldosterone secreting adrenal adenoma (Conn’s syndrome)

- Bilateral idiopathic adrenal hyperplasia

119
Q

What is the treatment for adrenal crisis?

A
  • Treated with venous cortisol (hydrocortisone)
  • Rapid Fluid replacement to avoid death.
  • Correction of hypoglycaemia
  • Search for precipitating cause (Addison’s for example)
120
Q

What is the most common enzyme in ACH?

A

21 hydroxylase

121
Q

What are the types of secondary hyperaldosteronism?

A
  • Renin producing tumour

- Renal artery stenosis

122
Q

What is the indication of secondary hyperaldosteronism?

A
  • High renin levels

- Low aldosterone:renin ratio

123
Q

What are the treatment for hyperaldosteronism?

A

Depends on the type

  • Aldosterone-producing adenomas removed by surgery
  • Spironolactone (mineralocorticoid receptor antagonist)
124
Q

What is the common enzyme defect in CAH?

A

21-hydroxylase deficiency

125
Q

What are the clinical features of Addison’s crisis?

A
  • Dehydration
  • Coma
  • Pigmentation
  • Hypotension
  • Vascular collapse
126
Q

What are the characteristics of pheochromocytoma?

A
  • Severe hypertension
  • Headaches
  • Palpitations
  • Diaphoresis
  • Anxiety
  • Weight loss
  • Elevated blood glucose
  • SUDDEN DEATH
127
Q

What are the tests for suspected adrenal insuffiency?

A
  • Electrolytes : low Na, High K in aldosterone deficiency
  • 0900 basal cortisol low : when it should be high
  • Stimulation test : inject with synthetic ACTH (synacthen)
128
Q

What are the tests for suspected adrenal insufficiency?

A
  • Electrolytes : low Na, High K in aldosterone deficiency
  • 0900 basal cortisol low : when it should be high
  • Stimulation test : inject with synthetic ACTH (synacthen)
129
Q

What are the test for suspected adrenal hormone excess?

A
  • Electrolytes : high BP, low K
  • Midnight cortisol high - should be low
  • 24h urine cortisol high
  • Suppression test - failure to suppress
  • Androgens and derivatives high
130
Q

What is the biochemical assessment for adrenal medulla?

A
  • 24h urine catelchoamines - adrenaline, noradrenlaine, dopmine, 3-methyl-tyramine
  • 24h urine metanephrines - met adrenaline, normatadrenaline (metabolites of adrenaline and noradrenaline)
  • Plasma metanephrines - more sensitive than 24h urine

avoid certain foods such as coffee, coke, bananas, chocolate, vanilla

131
Q

What are the different radiological assessment of adrenal disease?

A
  • CT scan
  • MRI scan
  • MIBG scan
  • PET scan
132
Q

How is Addison’s disease controlled?

A

Lifelong treatment with glucocorticoid (prednisone, hydrocortisone) and mineral corticoid (fludrocortisone)

Education to prevent crises - double dose of glucocorticoid at times of illness, Steroid card and bracelet and Emergency hydrocortisone if vomiting.

133
Q

What are the symptoms of ACTH deficiency and when does in occur?

A
  • Occurs in any case of hypopituitarism
  • Similar symptoms to adrenal failure
  • No pigmentation as ACTH not raised
  • No hyperkalaemia as no mineralocorticoid deficiency
  • Hyponatraemia due to effect of cortisol on free water secretion.
134
Q

What is steroid-induced hypoadrenalism?

A

ACTH suppressed with long term steroids so abrupt withdrawal can cause hypo-adrenal crisis
Important to consider in any unwell patients on steroids

135
Q

What is the presentation of adrenal cushing’s syndrome?

A 
ACTH suppressed
Androgenic symptoms may be present such as 
-Hirsutism
-Acne
-Greasy skin
136
Q

What are the treatment for phaeochromocytoma?

A
  • Alpha blockade (phenoxybenzamine)
  • Betablackage (bisoprolol)
  • Surgical excision
137
Q

What is an indication of nephropathy?

A

Increase in the amount of protein in urine. (microalbuminuria)

138
Q

What is the principle components of the calcium hydroxyapatite crystals?

A

Calcium and phosphate

139
Q

What is the major portion of the mineral phase of the bone made of?

A

Calcium Hydroxyapatite crystals

140
Q

What regulates the calcium and phosphate levels?

A
  • Parathyroid Hormone
  • Calcitriol
  • Calcitonin
141
Q

Where is most calcium located?

A

Bone. 1Kg

142
Q

What is a major source of calcium in the diet?

A

Dairy products

143
Q

What states does calcium exist in plasma?

A
  • As free ionised Species
  • Bound to anionic sites on serum proteins
  • Complexed with low molecular weight organic anions
144
Q

What is the result of hypocalcaemia?

A

Results in hyperexcitiability in the nervous system including the neuromuscular junction leading

  • Parathesia
  • Tetany
  • Paralysis
  • Convulsions
145
Q

What is the result of chronic hypercalcaemia?

A
  • Formation of kidney stones
  • Constipation
  • Dehydration
  • Kidney damage
  • Tiredness
  • Depression
146
Q

What are the actions of parathyroid hormone?

A
  • Raises calcium levels in short term regulation
  • Reduced renal phosphate reabsorption
  • Stimulates calcium reabsorption in kidney
  • Stimulates bone resorption and increased calcium release into circulation
  • Stimulates hydroxylation of
147
Q

What is action of Vitamin D?

A
  • Increase intestinal absorption of dietary calcium and renal reabsorption of calcium
  • Increase bone resorption
148
Q

What is action of calcitonin?

A

-Counteracts the effects of PTH

149
Q

How does hypercalcaemia affect plasma calcium levels?

A
  • Decreased PTH secretion
  • Less calcitriol from kidney so less calcium from gut and calcium reabsorption in the kidney
  • Less Ca2+ taken from the gut
  • Less bone breakdown and increase bone building
  • This all acts to decrease the plasma calcium levels.
150
Q

How does hypocalcaemia affect plasma calcium levels?

A
  • Increased PTH secretion
  • Increased calcitriol from the kidney which means more calcium absorbed form the gut and increase calcium reabsorption in the kidney.
  • Increased bone breakdown and decreased bone building
  • This all acts to increase the plasma calcium levels
151
Q

What is the effect of chief cells?

A

Produce parathyroid

152
Q

What is the active form of vitamin D and how is it produced?

A
  • Vitamin D from the sun exposure, food and supplements is biologically inert
  • Must undergo two hyrodxylation reaction to be activated in the body to form calcitriol
153
Q

What is the half life of parathyroid hormone?

A

4 minutes

154
Q

What can be secreted by some tumours which can lead to hypercalcaemia?

A

Parathyroid hormone related peptide.

155
Q

Why doesn’t calcitriol levels increase in humeral hypercalcaemia of malignancy?

A

Parathyroid hormone related peptide doesn’t cause an increase in calcitriol concentration as it doesn’t increase renal C-1 hydroxylase.

156
Q

True/False. Hypo or Hyper secretion of Calcitonin has a large effect on calcium.

A

False. Has very little function. Thyroid gland removal has no apparent effect on calcium homeostasis

157
Q

When is calcitonin suggested to have an impact?

A

During pregnancy it is suggested to preserve the maternal skeleton.

158
Q

Can parathyroid be stored?

A

Yes but has very little stores. It is synthesised continually
-Chief cells synthesise the hormone and degrade it.

159
Q

How does increase calcium levels affect parathyroid release?

A
  • Increased serum calcium levels.
  • Binding to specific receptor
  • GPCR activated
  • Decrease in transcription and release of parathyroid
160
Q

What does the body prioritise calcium levels or structural integrity?

A

Maintaining serum calcium is more important to the body than maintaining structural integrity.

161
Q

What are the actions of PTH in the bone referencing the cells?

A

Osteolysis

  • PTH induces osteoblastic cells to synthesise and secrete cytokines on cell surface
  • Cytokines stimulate differentiation and activity in osteoclasts and protect them from apoptosis
  • PTH decreases osteoblasts activity exposing bony surface to osteoclasts
  • Reabsorption of mineralised bone and release of phosphate and Ca2+ into extracellular fluid
162
Q

Why does the reabsorption of calcium and reabsorption of phosphate need to be regulated?

A
  • Calcium and phosphate need to be regulated as they can be reacted.
  • PTH increases calcium reabsorption and decrease phosphate reabsorption to stop the reaction and formation of hydroxyapatite crystals in kidney.
163
Q

How is Calcitriol formed?

A
  • Cholecalciferol is hydroxylated in the liver to form 25-hydroxycholecalciferol
  • 25-hydroxycholecalciferol is hydroxylated to form 1,25-dihydrocholecalciferol(calcitriol) using the enzyme 1-alpha-hydroxylase
164
Q

Which cells secrete calcitonin?

A

-Secreted by parafollicular cells or C cells of thyroid gland

165
Q

What are the pathological consequences of hypocalcaemia?

A

Hyperexcitability of neuromuscular junction

  • Pins and needles
  • Tetany
  • Paralysis
  • Convulsions
166
Q

What are the pathological consequences of hypercalcaemia?

hyperparathyroidism

A
  • Kidney stones
  • Kidney damage
  • Constipation
  • Dehydration
  • Tiredness
  • Depression
  • Polyuria

stones, mones and groans

167
Q

What is calcium in the clotting cascade?

A

Factor IV

168
Q

What has to be given to recipients of massive blood transfusions?

A

Intravenous Calcium. To allow clotting

169
Q

What are the common cancers that metastasise to bone causing lytic lesions and hypercalcaemia?

A
  • Breast
  • Lung
  • Renal
  • Thyroid
170
Q

Prostate cancer causes osteoblastic metastases that does not cause hypercalcaemia. True/False

A

True

171
Q

What is the aetiology of hypercalcaemia in a hospital setting?

A
  • Malignant osteolytic bone metastases

- Multiple myeloma

172
Q

What are the common sites for metastases?

A

Vertebrae, Pelvis, Proximal parts of the femur, Proximal part of the humerus and Skull. More than 90% of metastases are found in this distribution

173
Q

What is primary hyperparathyroidism?

A

One of the 4 parathyroid glands develops an adenoma and secretes excessive parathyroid hormone. This causes serum calcium rise and serum phosphate to fall

174
Q

What is secondary hyperparathyroidism?

A

All 4 parathyroid glands become hyperplastic.

-Due to vitamin D deficiency. Renal failure or dietary

175
Q

What can occur when the thyroid gland is taken out in surgery?

A

Accidentally take out the parathyroid

176
Q

What does an increased serum alkaline phosphatase show?

A

Increased bone turnover

177
Q

What does sever hypercalcaemia result in if polyuria continues?

A

Dehydration which exacerbates hypercalcaemia. this can lead to

  • Lethargy
  • Weakness
  • Confusion
  • Coma
  • Renal failure
178
Q

What is the mainstay treatment for dehydration as a result of severe hypercalcaemia?

A

Rehydration is the mainstay of treatment.

179
Q

When is symptomatic hypocalcaemia seen?

A

Seen mostly in post total-thyroidectomy patients. Symptoms can develop when serum calcium falls below 2.10 mmol/l and can start within 6 hours of thyroidectomy.

180
Q

What are the sensory symptoms of hypocalcaemia?

A

Tingling around the mouth and in fingers

181
Q

Why does hypocalcaemia need treating quickly?

A

Hypocalcaemia can kill due to laryngeal muscle tetany, so needs treating quickly

182
Q

What is osteoporosis?

A

Decreased bone density with a normal ratio of mineral to matrix. There is normal bone but not enough of it.

183
Q

What does osteoporosis lead to?

A

Leads to brittle bones that are prone to fractures

184
Q

What is osteomalacia?

A

The ratio of mineral to matrix is decreased. It is an abnormality that can affect bone building in children or bone mineralisation in adults. Leads to soft bones that are prone to bending.

185
Q

What can cause osteomalacia?

A
  • Dietary, environmental. In children it is called rickets

- Chronic renal disease - renal osteodystrophy

186
Q

What are the symptoms of osteomalacia in adults?

A
  • Bone pain
  • Muscle weakness
  • May lead to deformity
187
Q

What are the risks factors for osteoporosis?

A
  • Post menopausal women
  • Low body mass index (BMII)
  • Long-term oral steroid use
  • Heavy drinking
  • Smoking
  • Prolonged inactivity such as bed rest
188
Q

What are the 2 main levels of control of energy ?

A
  • Changing activity of enzymes in metabolic pathways

- Altering which substances can enter cells from the blood

189
Q

What is metabolic syndrome?

A

A cluster of most dangerous risk factors associated with cardiovascular disease

  • Diabetes
  • Raised plasma glucose
  • Abdominal obesity
  • High cholesterol
  • Blood pressure
190
Q

What is the cause of metabolic syndrome?

A 
Insulin resistance
Central obesity
Genetics
Physical inactivity
Ageing
191
Q

What are the acute complications of hypoglycaemia?

A
  • Coma

- Brain needs glucose. Caused by hypoglycaemic therapy

192
Q

How does insulin resistance occur in the young?

A

Insulin resistance present before onset of hyperglycaemia and development of overt type 2 diabetes

Initially:
-Beta cells compensate by increasing insulin production in order to maintain normal blood glucose

Eventually
-Beta cells unable to maintain increased insulin production so impaired glucose intolerance

Finally
-Beta cells dysfunction leads to relative insulin deficiency so overt type 2 diabetes

193
Q

What does insulin do?

A

Increases glucose uptake inc ells and glycogen synthesis

  • In the liver it increases glycogen synthesis by stimulating glycogen formation and by inhibiting breakdown
  • In muscle it increase uptake of amino acids promoting protein synthesis
  • In liver inhibits breakdown of amino acids
  • In adipose tissue increases the storage triglycerides
  • Inhibits the breaks of fatty acids
194
Q

How is diabetes diagnosed?

A
  • Random venous plasma glucose contraction of ≥ 11.1 mmol/L or
  • A fasting plasma glucose concentration ≥7.0 mmol/L (whole blood ≥6.1 mmol/L) or
  • Plasma glucose concentration ≥11.1 mmol/L 2 hours after 75g anhydrous glucose in oral glucose tolerance test
195
Q

What is paracetamol broken down into within it therapeutic window?

A

Glucuronide and sulphites

196
Q

How does increased alcohol intake exacerbate gout?

A
  • Decreased utilisation of lactate by liver cells
  • Increased accumulation in the blood and may cause lactic acidosis
  • Increased levels of lactate decrease kidneys ability to excrete uric acid which may exacerbate gout
197
Q

How does fasting hypoglycaemia occur with increased alcohol intake?

A
  • Low NAD+ level combined with the inability of the liver cells to use lactate and glycerol
  • Gluconeogenesis cannot be activated and fasting hypoglycaemia may become a serious problem
198
Q

What are used as markers of damaged hepatocytes?

A
  • AST
  • ALT
  • Gamma Glutamyl Transpeptidase
199
Q

Why are mitochondrial DNA paticularly sensitive to ROS damage?

A

mtDNA is situated near the inner mitochondria membrane where ROS are formed. It is also not protected by histones

200
Q

What is a Heinz body?

A

Red blood cels with precipitated cross linked haemoglobin

201
Q

How do free radical scavenger battle oxidative stress?

A

Donate Hydrogen atom to free radicals in non enzymatic reaction

202
Q

What is chronic granulomatous disease?

A

Defect in NADPH oxidase complex which causes enhanced susceptibility to bacterial infections

  • Atypical infections
  • Pneumonia
  • Abscesses
  • Impetigo
  • Cellulitis
203
Q

What is the action of glutamine synthetase and glutaminase?

A
  • Conversion of glutamate to glutamine using ammonium ions.
  • Glutamine is transported to the liver and the kidney where it is hydrolysed by glutaminase releasing ammonia
  • Ammonia can disposed of in the urine or converted to urea
204
Q

What is the significant of the glutamate dehydrogenase enzyme?

A
  • Catalyses the reaction of ammonia and alpha ketoglutarate to form glutamate in mitochondria.
  • Remove alpha ketoglutarate from the TCA cycle which slows, disrupting energy supply to brain cells

Kofi: Pure clinical conditions (8 decks)

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