Chem path Flashcards
(118 cards)
1
Q
Units for osmolality
A
Mmol/kg
2
Q
Units for osmolarity
A
mmol/l
3
Q
Osmolarity calculation
A
2(Na+K) + urea + glucose
4
Q
Normal range for osmolality
A
275 - 295 mmol/kg
5
Q
Normal range sodium
A
135 - 145 mmol/l
6
Q
Symptoms of hyponatraemia, starting with symptoms experienced as Na falls
A
Nausea and vomiting (
7
Q
What can happen if you correct hyponatraemia too fast? What rate should you aim for?
A
Central pontine myelinosis (pseudobulbar palsy, paraperesis, locked-in syndrome)
Rate: 1mmol/l per hour
8
Q
Two reasons why hyponatraemia may occur post-surgery?
A
Over hydration with hypotonic IV fluids
Transient increase in ADH due to stress of surgery.
9
Q
Causes of SIADH
A
Malignancy - small cell lung cancer, pancreas, prostate, lymphoma
CNS disorders - meningoencephalitis, haemorrhage, abscess
Chest - TB, Pneumonia, abscess
Drugs - opiates, SSRIs, carbamazepine
10
Q
Symptoms of hypernatraemia
A
Thirst Confusion Seizures and ataxia Coma Death
11
Q
Three types of ECF
A
Intravascular
Transcellular
Interstitial
12
Q
What is the test used in diagnosing Diabetes Insipidus? There are four potential type of results from the test, name them and what you would expect to see.
A
8hr fluid deprivation test
Normal: Urine concentration >600mOsmol/kg
Primary polydipsia: Urine concentrates >400-600mOsmol/kg
Cranial DI: urine concentrates only after giving desmopressin
Nephrogenic DI: zero concentration urine after desmopressin
13
Q
What is the normal range for potassium? (with units)
A
3.5-5.5mmol/l
14
Q
Four causes of hypokalaemia?
A
GI loss Renal loss (hyperaldosteronism, excess cortisol) Redistribution into the cells (insulin, beta-agonists, alkalosis) Rare causes (tutbular acidosis type 1 & 2)
15
Q
Normal pH range
A
7.35-7.45
16
Q
normal CO2 range
A
4.7-6kPa
17
Q
normal bicarbonate range
A
22-30mmol/l
18
Q
normal O2 range
A
10-13kPa
19
Q
Anion gap calculation
A
(Na + K) - (Cl + HCO3)
20
Q
Normal anion gap range
A
14-18 mmol/l
21
Q
Causes of a metabolic acidosis with elevated anion gap
A
mnemonic KULT
Ketoacidosis (DKA, alcoholic, starvation)
Uraemia (renal failure)
Lactic acidosis
Toxins ( ethylene glycol, methanol, paraldehyde, salicylate)
22
Q
Osmolar gap calculation
A
Osmolality (measured) - Osmolarity (calculated)
23
Q
What is the normal osmolar gap?
A
24
Q
Normal range of AST/ALT
A
25
What causes AST/ALT (the aminotransferases) to rise?
Death of hepatocytes
26
What condition causes an AST:ALT of 2:1
Alcoholic liver disease
27
What condition causes an AST:ALT of
Viral liver disease
28
What is the normal range of ALP?
30-150iu/L
29
In what conditions does ALP rise?
cholestasis (intra/extrahepatic)
Bone disease
Pregnancy
30
What is the normal range of GGT
15-85iu/L men
| 5-55iu/l women
31
What causes GGT to rise?
chronic alcohol use
bile duct disease
metastases
32
Acute intermittent porphyria is characterised by what enzyme? Is it raised or low?
Porphobilinogen (PBG) deaminase deficiency
33
What are the symptoms of acute intermittent porphyria?
```
Abdominal pain
Seizures
Psych disturbances
N+V
Tachycardia
Muscle weakness
NO cutaneous manifestations
```
34
What are the 6 Ps of Acute Intermittent Porphyria?
```
Porphobilinogen deaminase deficiency
Pain in abdomen
Psychological symptoms (anxiety, hallucinations)
Peripheral neuropathy (patchy numbness)
Pee abnormality (dark urine)
Precipitated by drugs (barbiturates, oral contraceptives)
```
35
How to diagnose acute intermittent porphyria
aminolevulinic acid (ALA) and porphobilinogen (PBG) in the urine
36
What are the three aspects to interpret in the combined pituitary function test?
Insulin Tolerance Test
Thyrotrophin Releasing Hormone Test
Gonadotrophin Releasing Hormone Test
37
What is an adequate cortisol response in an Insulin Tolerance test?
Rise above 550 nmol/l =normal
400-550 =impaired
Rise of less than 170 = Cushing's syndrome
38
What is an adequate growth hormone response in an Insulin tolerance test?
greater than 6 mcg/l
39
In primary hypothalamic disease which would be greater in a TRH test? 30min or 60min TSH levels?
60min
40
What hormones are produced from the anterior pituitary?
ADH and Oxytocin
41
In diabetes insipidus, which of the following are raised or low: urine osmolality; serum osmolality.
Urine osmolality is decreased
| Serum osmolality is raised
42
Normal range for TSH?
0.33-4.5 mu/L
43
Normal range for free T4?
10.2-22.0 pmol/L
44
normal range of free T3?
3.2-6.5 pmol/L
45
Raised TSH, Low T4
Hypothyroidism
46
Raised TSH, normal T4
Treated hypothyroidism/subclinical hypothyroidism
47
Raised TSH, raised T4
TSH secreting tumour or thyroid hormone resistance
48
Low TSH, raised T4 or T3
Hyperthyroidism
49
Low TSH, normal T3 and T4
Subclinical hyperthyroidism
50
Low TSH, Low T4
Central hypothyroidism (hypothalamic/pituitary disorder)
51
Raised (then later low) TSH, low T3 and low T4
Sick euthyroidism (with any severe illness)
52
Normal TSH, abnormal T4
?assay interference
TBG changes
amiodarone
53
Which thyroid conditions on an isotope scan will have 'high uptake'?
Graves
Toxic multinodular goitre
Toxic adenoma
54
Which thyroid conditions will have low uptake on an isotope scan?
Subacute DeQuervains thyroiditis
| Postpartum thyroiditis
55
Which thryoid condition has a 'hot nodule' on an isotope scan?
Toxic adenoma
56
Which thyroid condition is a self-limiting, post-viral painful goitre?
Subacute DeQuervains thyroiditis
57
Name two autoimmune forms of hypothyroidism
Primary atrophic hypothyroidism
| Hashimotos thyroiditis
58
'Diffuse lymphocytic infiltration, atrophy and no goitre' describes which thyroid condition?
Primary atrophic hypothyroidism
59
'Plasma cell infiltration and a goitre' describes which thyroid condition?
Hashimotos thyroiditis
60
In general how would you treat low uptake hyperthyroid conditions?
Symptomatically
| beta-blockers
61
In general, how would you treat high uptake hyperthyroid conditions?
betablockers
antithyroid therapy
carbimazole
62
Name 5 different categories of Thyroid neoplasias
```
Papillary
Follicular
Medullary
Lymphoma
Anaplastic
```
63
What causes a phaeochromocytoma?
Adrenal medulla tumour leading to increased adrenaline
64
Signs and symptoms of Cushing's?
```
Moon face
Buffalo hump
Striae
Acne
Hypertension
Diabetes
Proximal myopathy
Hirsutism
```
65
Signs and symptoms of Addison's?
```
Raised potassium
Low sodium
Low glucose
Postural hypotension
Skin pigmentation
Lethargy
Depression
```
66
Signs and symptoms of Conn's?
Raised sodium
Low potassium
Uncontrollable hypertension
67
Signs and symptoms of a phaeochromocytoma?
```
Headache
Flank Pain
Tachycardia
Palpitations
Paroxysmal Hypertension (sporadic/episodic)
Orthostatic Hypotension
Diaphoresis (excessive sweating)
Elevated glucose
DEATH
```
68
Investigation for Cushing's?
Low dose dexamethasone (0.5mg)
High dose dexamethasone (2mg)
ACTH levels
69
Investigations for Addison's?
SynACTHen test
70
Investigations for Conn's?
Aldosterone:Renin ratio will be raised
| To diagnose: saline suppresion test; ambulatory salt loading test; or fludrocortisone test.
71
Investigations for a phaeochromocytoma?
plasma and 24hr urinary metaadrenaline measurement + catecholamines
72
Normal plasma range of calcium?
2.2-2.6mmol/l
73
What four effects does PTH have in relation to calcium?
1) increased 1alpha hydroxylation of VitD
2) mobilises calcium from bone
3) increased renal calcium reabsorption
4) increased renal phosphate excretion
74
What effects does calcitriol have on bone and calcium?
Increased calcium and phosphate absorption from the gut
| Bone remodelling
75
```
Ca - raised
PO4 - low
PTH - raised/normal
Alk Phos - raised/normal
Vit D - normal
```
Primary hyperparathyroidism
76
```
Ca - low/normal
PO4 - raised
PTH - raised
Alk Phos - raised
Vit D - normal
```
Secondary hyperparathyroidism
77
```
Ca - raised
PO4 - low
PTH - raised
Alk Phos - raised/normal
Vit D - normal
```
Tertiary hyperparathyroidism
78
```
Ca - low
PO4 - raised
PTH - low
Alk Phos - low/normal
Vit D - normal
```
hypoparathyroidism
79
```
Ca - low
PO4 - low
PTH - raised
Alk Phos - raised
Vit D - low
```
Ricket's/ostseomalacia
80
```
Ca - normal
PO4 - normal
PTH - normal
Alk Phos - raised
Vit D - normal
```
Paget's disease
81
```
Ca - normal
PO4 - normal
PTH - normal
Alk Phos - normal
Vit D - normal
```
Osteoporosis
82
Symptoms of hypercalcaemia
```
Stones (renal)
Bones (pain)
Groans (psych)
Moans (abdo pain)
Polyuria
Muscle weakness
```
83
In general how do you approach treating hypercalcaemia?
Correct dehydration
Bisphosphonates
Correct the cause
84
Symptoms of hypocalcaemia
Perioral paraesthesia
Carpopedal spasm
Neuromuscular excitability - Trousseau's and Chvostek's signs.
85
What is Trousseau's sign and what condition is it associated with?
After inflating a BP cuff above systolic pressure on the patient's arm will induce spasm of the hand/forearm.
Associated with hypocalcaemia.
86
What is Chvostek's sign and what condition is it associated with?
Tapping the facial nerve at the angle of the jaw will induce muscle twitch on that side of the face.
It is associated with hypocalcaemia.
87
What acute condition is associated with high serum amylase?
Acute pancreatitis
88
In what pathology will Creatine Kinase be raised?
Duchenne Muscular Dystrophy
Myocardial Infarction
Rhabdomyolysis
89
In who may Creatine Kinase be physiologically raised?
Afro-Caribbeans
90
In who may ALP be raised physiologically?
Pregnant women
| Children during growth spurts
91
In what pathologies may ALP be raised?
BONE: Pagets; osteomalacia (less raised: tumours, fractures, osteomyelitis)
LIVER: Cholestasis; Cirrhosis (less raised: infiltrative disease, hepatitis)
92
What is Troponin a marker of and when should it be measured?
myocardial injury biomarker
| Measure at 6 hours then at 12 hours post-onset of chest pain
93
What type of protein is CRP, what is its time frame and what sort of concentration you expect to see in a normal person.
Acute phase protein
~6-8 hours after tissue damaage, peaking around 24 hours
serum conc. of around 5-10mg/L
94
What enzyme is deficient in Wilson's disease?
Caeruloplasmin
95
What protein is associated with Prostate Cancer?
PSA
96
What protein is associated with Hepatic Cancer?
AFP
97
What protein is associated with Pancreatic Masses?
CA19-9
98
What protein is associated with Ovarian Cancer/Pelvic Masses?
CA125
99
What protein is associated with Colorectal Cancer?
CEA
100
What protein is associated with Gestational Trophoblastic Disease?
bHCG
101
PSA is a tumour marker of what?
Prostate Cancer
102
AFP is a tumour marker of what?
Hepatic Cancer
103
CA19-9 is a tumour marker of what?
Pancreatic masses
104
CA125 is a tumour marker of what?
ovarian cancer/pelvic masses
105
CEA is a tumour marker of what?
Colorectal Cancer
106
beta HCG is a tumour marker of what?
Gestational Trophoblastic Disease
107
Phenylketonuria is caused by what pathology? How do we screen for this condition?
Phenylalanine hydroxylase deficiency
Screen using the guthrie test
108
Which six inherited metabolic diseases are newborns screened for? What other three conditions are newborns screened for?
```
PKU - Phenylketonuria
MCADD - Medium-chain acyl-CoA dehydrogenase deficiency
MSUD - Maple syrup urine disease
IVA - isovaleric acidaemia
GA1 - glutaric aciduria type 1
HCU - homocystinuria
```
Also: sickle cell; cystic fibrosis; congenital hypothyroidism
109
Galactosaemia Type 1 is associated with what enzyme deficiency?
Galactose-1-phosphate uridyl transferase (Gal-1-PUT)
110
Galactosaemia Type 2 is associated with what enzyme deficiency?
Galactokinase
111
Galactosaemia Type 3 is associated with what enzyme deficiency?
UDP galactose epimerase
112
How and when can Barth syndrome present?
From birth
Cardiomyopathy (dilated or hypertrophic)
Neutropenia (chronic, cyclic or intermittent)
Myopathy
113
What does MELAS stand for? What is the pathology? How and when does it present?
Mitochondrial Encephalomyopathy Lactic Acidosis and Stroke like episodes.
Defective mitochondrial genome
Presents in childhood after a period of normal development.
Muscle weakness, vomiting, stroke-like episodes
114
What is the pathology of Kearns-Sayre syndrome?
When and how does it usually present?
Mitochondrial disorder
Before the age of 20.
Unilateral ptosis that worsens resulting in the person extending their neck to see.
Later, reduced eye movements leading to movement of the head to see the peripheries.
Retinopathy - "salt and pepper"
Cardiopathy - AV block
115
What result on an oral glucose tolerance test is classified as diabetes?
>11.1 mmol/l 2-hours after the test
116
What result on an oral glucose tolerance test is classified as an impaired glucose tolerance?
Between 7.8-11.1 mmol/l 2 hours after the test.
117
To diagnose diabetes what result do you expect on a fasting plasma glucose?
>7mmol/l
118
Impaired fasting glycaemia is indicated by what fasting plasma glucose result?
A value between 6.1-7.0mmol/l
