Lipoprotein Metabolism, Metabolic Disorders, Hyper/Hypo Glycaemia, Flashcards

1
Q

Lipoprotein Metabolism

A

page 76 in path guide has a great flow chart for this, not sure how to put photos on here so feel free to add if you would like. i will put it into words for anyone who wants it though…

fats in diet are absorbed in the small intestine to form Chylomicrons - converted via LPL to Remnants -> Liver where they are converted to vLDLs. vLDLsconvert to LDLs via LPL and HPL or go to adipose tissue and then back to the liver via FFA and albumin

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2
Q

Lipoproteins in order of density

A
Chylomicron 
FFA
vLDL
IDL
LDL
HDL
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3
Q

PCSK9…what does it do?

A

ProProtein Convertase Subtilisin/Kexin type 9
-Binds LDLReceptor (which breaks down LDL) and promotes its degradation
-Loss of function mutation of PCSK9 -> low LDL levels
Novel form of LDL-lowering therapy is Anti-PCSK9 MAb

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4
Q

Fat soluble Vitamins

A

A - retinol
D - Chole-calciferol
E - Tocopherol
K - Phytomenadione

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5
Q

Fat soluble Vitamins - A - Retinol

  • Deficiency?
  • Excess?
  • Test?
A
  • Colour blindness
  • Exfoliation, Hepatitis
  • Serum
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6
Q

Fat soluble Vitamins - D - Chole-calciferol

  • Deficiency?
  • Excess?
  • Test?
A
  • Osteomalacia/ Rickets
  • Hypercalaemia
  • Serum
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7
Q

Fat soluble Vitamins - E - Tocopherol

  • Deficiency?
  • Test?
A
  • Anaemia/ Neuropathy, ?malignancy/IHD

- Serum

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8
Q

Fat soluble Vitamins - K - Phytomenadione

  • Deficiency?
  • Test?
A
  • Defective clotting

- PTT

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9
Q

Water soluble vitamins

A
B1 - Thiamin
B2 - Riboflavin
B6 - Pyridoxine
B12 - Cobalamin
C - ascorbate
Folate
B3 Niacin
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10
Q

Water soluble vitamins - B1 - Thiamin

  • Deficiency?
  • Test?
A
  • Beri-Beri, Neuropathy, Wernicke Syndrome

- RBC tranketolase

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11
Q

Water soluble vitamins - B2 - Riboflavin

  • Deficiency ?
  • Test?
A
  • Glossitis

- RBC glutathione reductase

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12
Q

Water soluble vitamins - B6 - Pyridoxine

  • Deficiency?
  • Excess?
  • Test?
A
  • Dermatitis/ anaemia
  • Neuropathy
  • RBC AST activation
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13
Q

Water soluble vitamins - B12 - Cobalamin

  • Deficiency?
  • Test?
A
  • Pernicious anaemia

- Serum B12

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14
Q

Water soluble vitamins - C - ascorbate

  • Deficiency?
  • Excess?
  • Test?
A
  • Scurvy
  • Renal Stones
  • Plasma
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15
Q

Water soluble vitamins - Folate

  • Deficiency?
  • Test?
A
  • Megaloblastic anaemia, Neural tube defect

- RBC folate

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16
Q

Water soluble vitamins - B3 Niacin

- Deficiency?

A

-Pellagra - 3Ds …
…Dementia
…Dermatitis
…Diarrhoea

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17
Q

Trace elements - Iron

  • Deficiency?
  • Excess?
  • Test?
A
  • Hypochromic anaemia
  • Haemochromatosis
  • FBC, Fe, Ferritin
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18
Q

Trace elements - Iodine

  • Deficiency?
  • Test?
A
  • Goitre, Hypothyroid

- TFT

19
Q

Trace elements - Zinc

- Deficiency?

A
  • Dermatitis
20
Q

Trace elements - Copper

  • Deficiency?
  • Excess?
  • Test?
A
  • Anaemia
  • Wilson’s Disease
  • Cu, Caeroplasmin
21
Q

Trace elements - Fluoride

  • Deficiency?
  • Excess?
A
  • Dental caries

- Flourosis

22
Q

Current UK screening of Metabolic Disorders and the tests carried out

A

1) Phenylketonuria - Guthrie Test
2) Congenital hypothyroidism - Test TSH levels
3) Cystic Fibrosis - Test immune reactive trypsin, if + = DNA mutation detection
4) Sickle cell disease
5) Medium Chain AcylCoA dehydrogenase Deficiency - test Acylcarnitine levels by tandem Mass Spectrometry

23
Q

Urea Cycle Disorders

  • Inheritance
  • Red Flags
  • Treatment
A
  • Autosomal recessive ( except for Ornithine Transcarbamylase Deficiency - X linked)
  • Red flags
    • Vomiting without diarrhoea
    • Hyperammonia and Resp Alkalosis
    • Encephalopathy
    • Change in diet
  • Remove ammonia. Reduce ammonia production
24
Q

Organic Acidurias - what is it?

A

A group of metabolic disoders that disrupt amino acid metabolism, particularly branched amino acids (leucine, isoleucine and valine)

25
Q

Organic Acidurias - Neonates - presentation and Bloods

A

Presentation
-Unusual odours, lethargy, feeding problems
- Truncal hypotonia/Limb hypertonia, myoclonic jerks
Bloods
- Hyperammonia with metabolic acidosis and high anion gap (not lactate)
- Hypocalcaemia, Neutropenia, Thrombopenia, Pancytopenia

26
Q

Organic Acidurias - Chronic Intermittent forms of fatty acid oxidation. Present with Recurrent episodes of …

A

Ketoacidotic coma
Cerebral abnormalities
Reye Syndrome
- Vomiting, lethargy, confusion, seizures, decerebration, resp arrest
- Triggers = salicylates, antiemetics, valproates

27
Q

Galactosaemia - what is it?

A

Glucose-1-phosphate uridylyltransferase deficiency (GAL-1-PUT) is the most severe of the 3 unknown disorders. Raised Gal-1-PUT causes liver and kidney disease

28
Q

Galactosaemia - Presentation

A

Vomiting, diarrhoea, conjugated hyperbilirubinaemia, hepatomagaly, hypoglycaemia and sepsis

29
Q

Galactosaemia - Lab investigations

A

Urine reducing substances, Red cell GAL-1-PUT

30
Q

Glycogen storage disorders - what is it? due to? leads to?

A

A result of defects in glycogen synthesis or breakdown. Commonly have muscular, liver and other consequences.

11 types altogether, all due to enzyme deficiencies. GSD type 1 (von Gierke’s disease) is glucose-6-phosphatase deficiency

Leads not only to excessive glycogen storage but also prevents glucose export from gluconeogenetic organs

31
Q

Glycogen storage disorders - Presentation

A
Lactic acidosis
Convulsions
Hypoglycemia (Irritability, pallor, cyanosis, hypotonia, tremors, loss of consciousness and apnea)
Hepatomegaly
Hyperlipidaemia
Hyperuricaemia
Neutropaenia
32
Q

Lysosomal Storage Disease

  • what is it? what does it lead to?
  • Lab invetigations?
  • Treatment?
A
  • Intraorganelle substrate accumulation leading to organomegaly and consequent dysmorphia and regression.
  • Lab Investigations - Urine mucopolysaccharides and Oligosaccharides, Leucocyte enzyme activity
  • Treatment - Bone Marrow transplant, exogenous enzymes
33
Q

Peroxisomal Disorders

A

Disorder in metabolism of very long chain fatty acids and biosynthesis of complex phospholipids

34
Q

Peroxisomal Disorders in Neonates - symptoms

A
  • Severe muscular hypotonia, seizures
  • Hepatic dysfunction - mixed hyperbilirubinaemia
  • Dysmorphic signs
35
Q

Peroxisomal Disorders in Infants - symptoms

A
  • Retinopathy (often leading to early blindness), sensorineural deafness, mental deficiency
  • Hepatic dysfunction
  • Large fontanelle, osteopenia of long bones, calcified stippling
36
Q

Peroxisomal Disorders - Lab investigations

A

Very long chain fatty acids

37
Q

Mitochondrial disorders - what is it?

A

Defective ATP production leads to multi systemic disease especially affecting organs with a high energy requirement such as brain, muscle, kidney, retina and endocrine organs

38
Q

Mitochondrial disorders - age, disorder, presentations?

A
  • Birth - Barth Disorder - Cardiomyopathy, neutropenia, myopathy
  • 5-15 years - MELAS Disorder - Mitochondrial Encephalopathy, Lactic acids and stroke-like episodes
  • 12-30 years - Kearns Sayre Disorder - CPEO, retinopathy, deafness, ataxia
39
Q

Diabetes Mellitus

  • Diagnosis?
  • HbA1C?
  • GTT?
  • Fasting Glucose?
A
  • 90% T2DM
  • Diagnosis - made with either typical symptoms plus one off fasting glucose >7, OGTT >11.1 or random glucose >11.1 or made without symptoms via 2 tests
  • HbA1C >48
  • Random/Oral GTT >7.8 but 6.1 but
40
Q

Hypoglycaemia - classification

A

1) Hyperinsulinaemic hypoglycaemia - Iatrogenic insulin, sulfonylurea excess, insulinoma
2) hypoinsulinaemic hypoglycaemia
a) +ve Ketones - Alcohol binge no food, Pituitary insufficiency, Addison’s, Liver failure
b) -ve Ketones - Non Pancreatic neoplasms - Fibrosarcomata, fibromata

41
Q

Causes of Hypoglycaemia with low insulin and C-peptide in Adults?

A

Adults

  • Fasting
  • Strenuous excerise
  • Critical Illness
  • Endo deficiency - Hypopit, adrenal failure
  • Liver failure
  • Anorexia Nervosa
42
Q

Causes of Hypoglycaemia with low insulin and C-peptide in Neonates?

A

Ketones present

  • Premature
  • IUGR
  • Co morbidity

Ketones absent
-Inherited Metabolic Disorder

43
Q

Causes of Hypoglycaemia with high insulin?

A

Endogenous Cause

  • Insulinoma - requires -ve sulphonylurea screen
  • Quinine
  • Pentamidine
44
Q

Non-Islet tumour hypoglycaemia

A

LOW Glucose, insulin, C-peptide, FFA, Ketones

Tumours that can cause a paraneoplastic syndrome, secreting Big IGF-1, which binds to IGF-1 and Insulin receptors