Chemical pathology Flashcards
1
Q
what are the breakdown products of heroin?
A
6-MAM, morphine, 3-MAM
2
Q
A man was put into custody after driving under the influence of drugs. On arrest he was reported as acting extremely aggressive and paranoid. He also claimed his heart was racing. One hour later he was found dead. What is the likely drug of abuse?
A
cocaine
3
Q
WCC reference range?
A
4.0 - 11.0
4
Q
PTH refrence range
A
10 - 60 ng/L, 1.05 - 6.83 pmol/L
5
Q
corrected calcium ref range
A
2.05 - 2.60 mmol/L
6
Q
Which drug is found in the most addict related deaths?
A
cocaine
7
Q
What is a disadvantage of using saliva for forensic drug analysis?
A
small window of detection
8
Q
which drug is not excreted into saliva?
A
THC
9
Q
what are the serious adverse effects of theophylline?
A
tachyarrhythmia, seizures, diarrhoea
10
Q
what are the features of digoxin toxicity?
A
- arrhythmia
- specifically ventricular ectopics, bigeminy/trigeminy or complete heart block
- GI - anorexia, neusea, vomiting
- confusion (esp elderly)
- VISUAL - yellow vision, blurred vision, photophobia
11
Q
treatment for beta-blocker OD?
A
IV atropine for heart rate stabilisation
If still sick, IV glucagon
Glucagon - couteracts hyperglycaemia and activates Gs on heart, increasing cAMP behaving as positive inotrope
12
Q
what toxins are not treated with activated charcoal?
A
- cyanide
- iron
- ethanol
- lithium
- acid base disturbance
- pesticides
13
Q
what is the indication for activated charcoal?
what advice should be given to patients?
A
poisoning with a PO drug immediately after ingestion
given in a dose approx 10:1 w/w charcoal:drug, or 50g q4hr
will taste awful and poo will be black
14
Q
what is the treatment for severe salicylate toxicity (with severe acid base disturbance)
A
haemodialysis
15
Q
at what [glucose]serum does polyuria usually develop as a symptom?
A
> 10 mM
16
Q
what are the situations in which HbA1c is a bad test of diabetic control?
A
IDA
haemaglobinopathy
17
Q
what is the diagnostic criteria of diabetes by HbA1c?
A
value of > 48 mmol/mol (6.5%) on 2 occasions
sample NOT done by finger prick test
18
Q
procedure of OGTT
A
- overnight fast
- 75 g glucose in 250 - 250 mL water (440 mL lucozade)
- take blood at t = 0, 60 mins & 120 mins
19
Q
diagnostic definition of diabetes
fasting and OGTT
A
fasting >= 7.0
120 mins OGTT >= 11.1
20
Q
diagnostic definition impaired glucose tolerance
results from OGTT
A
120 mins OGTT = 7.8 - 11.0 mmol/L
21
Q
diagnostic definition impaired fasting glucose
A
fasting = 6.1 - 6.9 mmol/L
22
Q
a pregnant woman with 120 mins OGTT = 7.8 - 11.0 should be treated how?
A
as though she has GDM
23
Q
which antibiotic should have peak and trough levels measured?
A
gentamicin
24
Q
thiazide diuretics affet the renal clearance of which notoriously toxic medication?
A
lithium
25
which liver enzyme will be raised in MI?
AST
26
which blood test(s) varies with posture when taken?
albumin
renin
27
which blood test has the greatest variability with race?
CK
28
what hormonal disturbance can be caused by ecstasy?
SIADH and hyponatraemia
29
most common cause of addison's disease worldwide?
tuberculosis
30
Na + = 115 mmol/L
K + = 6.3 mmol/L
Osm = 210 mmol/L
addison's disease
31
a 2/12 old baby vomits profusely.
pH = 7.57, H+ = 26 nmol/L ( rr: 35-45 nmol/L), HCO3- = 50 mmol/L
what is the likely accompanying eletrolyte disturbance?
hypokalaemia
32
what are the principle differences between type 1 and 2 RTA?
type 1 = failure to excrete H+ in DCT & CD
type 2 = failure to resorb HCO3- in PCT
33
what are the 3 principle characteristics of RTA?
1. acidosis with HYPOkalaemia
2. alkaline urine with positive anion gap
3. nephrocalcinosis
34
which RTA is most common?
what are the aetiologies of both?
type 1 more common
* type 1 = idiopathic, autoimmune (SLE), chronic pyelonephritis
* type 2 = fanconi syndrome
35
what is delayed separation?
when you leave a vial of blood lying around too long and K+ leaks out from RBC and contaminates the result (falsely eleveated K+)
36
what disease results in
hypervolaemia with urinary Na+ \> 20 mmol/L
chronic renal failure
37
what must you consider with:
normovolaemic and hyponatraemic
SIADH
38
high dose dex supression test
cortisol levels high and rest and supressed in response..
diagnosis?
cushing disease
ACTH secreting pit adenoma
39
a 52 y/o male presents with muscle cramps and headache
hypertensive and HYPOkalaemia
renin-aldosterone ratio = 0.02
diagnosis?
aldosterone-secreting adrenal adenoma
40
excess ACTH symptoms following bilateral adrenalectomy..
eponymous syndrome
nelson's syndrome
41
what steroid is detectable in the urine of CAH patients ?
pregnanetriol
42
what is the gold standard for measurement of GFR?
inulin
43
A 65 yr old woman presents with a four week Hx of weight gain, tiredness, constipation and a puffy face. On Ix she is found to have a TSH level of 20mU/l and a free T4 level of 7pmol/l
primary hypothyroidism
44
A 35 yr old woman presents with pain in her neck which radiates to her upper neck, jaw and throat. The pain is worse on swallowing. She has a Hx of an upper respiratory tract infection two weeks ago. On Ix she has a free T4 of 30pmol/l, free T3 of 11pmol/l and a TSH level of 0.1mU/l. On technetium scanning of the thyroid there is low iodine uptake.
de Quervain's thyroiditis
| (or subacute granulomatous; viral; painful)
45
A 30 yr old woman presents with a Hx of weight loss, diarrhoea, tremor and a marked swelling at the front of her neck. On Ix she is found to have a TSH level of 0.05mU/l a free T4 level of 30pmol/l and a free T3 of 12pmol/l. On technetium scanning the thyroid shows increased iodine uptake.
Graves disease
46
A 70 yr old lady is found to have a tumour of the thyroid gland. She is also found to have high levels of circulating calcitonin
medullary thyroid CA
47
Neurotoxic product(s) of heme breakdown producing neurovisceral damage in certain porphyrias
5-ALA
aminolevulinic acid
48
Product(s) of heme breakdown resulting in photosensitivity (i.e. cutaneous) damage in certain porphyrias
activated porphyrins and oxygen free radicals
49
what is pseudo-hyponatraemia?
increased lipids and proteins in the serum means a lower sodium concentration is detected due to dilution
there is an apparent hyponatraemia without other deranged U&Es
50
what is the numerical osmolality of plasma in SIADH?
plasma \<270 mmol/L
51
the urine osmolality is greater than plasma osmolality in which condition?
SIADH
52
what is the best test for hypovolaemia?
Low urine Na (\<20)
kidney notices hypovelaemia and retains salt and water to compensate
53
what are the causes of hypovolaemic hyponatraemia?
diarrhoea, vomiting
diuretics
salt wasting nephropathy
54
what are the causes of euvolaemic hyponatraemia?
hypotothyroidism
adrenal insufficiency
SIADH
55
what are the causes of hypervolaemic hyponatraemia?
cardiac failure
renal failure
liver failure
56
in what instance are fluids contraindicated in hyponatraemia?
what is the mechanism?
SIADH
high circulating ADH, give 0.9% saline. retain all the water, excrete the salt. overcome the protective natriuretic peptide effect and go into further hyponatraemia/fluid overload
57
what is the treatment of SIADH?
treat the underlying cause + EITHER
**fluid restriction with IV hypertonic saline + frusemide**
OR
**Tolvaptans (V2 receptor antagonist)/demeclocycline**
58
what electrolyte abnormalities can cause a nephrogenic diabetes insipidus?
hypokalaemia and hypercalcaemia
59
what is translocational hyponatraemia?
high glucose in the serum draws water out into the extracellular space which dilutes the sodium causing a translocational hyponatraemia
60
management of hyperkalaemia?
1. 10 ml 10% calcium gluconate
2. 50 ml 50% dextrose & 10 U insulin
3. Nebulised salbutamol
4. Treat underlying cause
61
causes in order of likelihood for hyperkalaemia
CKD
Drugs - ACE-I, ARB, sprionolactone
Endo - Addison's, type IV RTA
Release from cells - rhabdomyolysis, systemic acidosis
62
algorithm for hypokalaemia
* GI loss.
* Renal loss:
* hyperaldosteronism (excess cortisol);
* increased sodium delivery to DCT;
* Osmotic diuresis.
* Redistribution into the cells:
* insulin; beta-agonist; alkalosis.
* Rare - RTA I & II, hypomagnesaemia.
63
muscle weakness
cardiac arrhythmia
polyuria and polydipsia
what is the abnormality?
hypokalaemia
remember: hypokalaemia and hypercalcaemia cause nephrogenic DI
64
what is the treatment algorithm for hypokalaemia?
if 3.0-3.5
two SandoK tablets tds for 48 hours, then review
if \<3.0
IV KCl in normal saline, max 10 mmol/hr.
65
what are the osteolytic bone met primaries?
BLT with Kosher Pickle, Mustard & Mayo
breast, lung, lymphoma, thyroid, kidney, prostate, Multiple Myeloma
66
what is the urgent management for hypercalcaemia?
FLUIDS
4 L in 24 hours 0.9% saline
or
frusemide & fluids if volume overloaded (must start calciuresis)
67
after calciuresis, what is the next step in management of hypercalcaemia?
keep well hydrated
avoid thiazides
surgery (parathyroidectomy)
68
what is the treatment for hypercalcaemia in malignancy?
fluids and IV pamidronate 30-60 mg
69
on hand x-ray, what does radial aspect cystic changes suggest?
primary hyperparathyroidism
70
what is a Looser's zone?
feature of Vitamin D deficiency
71
what is the pathogenesis of pseudohypoparathyroidism?
inherited resistance to PTH, TSH (mild) and LH
Very high PTH, low Ca++, high Phosphate, normal ALP
female - hypogonadotrophic hypogonadism
hypocalcaemia = carpopedal spasm, parasthesia etc.
Albright hereditary osteodystrophy = short, mental retardation, obese, strabismus, ocular opacities, subcut calcifications, short metacarpals/metatarsals
72
elevated - ALP, PTH
decreased - Ca++, Phos, Vit D
diagnosis?
osteomalacia/rickets
73
A 32 year old librarian presents to your clinic complaining of blurring of her vision and amenorrhoea. She has a BMI of 22 and is generally well but has noticed some white secretions from her breast over the past 3 months. What would be a first line investigation for this lady?
CT head
74
what is given for a complete pituitary function test?
100 mcg **GnRH**, 200 mcg **TRH**, **insulin** (complicated dose)
75
at what point is there increased cardiovascular risk with the following parameters:
LDL, HDL, cholesterol:HDL ratio
LDL \> 4.1 mmol/L
HDL \<0.9 mmol/L
Ratio \>5
76
at what point in there decreased cardiovascular risk with LDL and HDL levels?
LDL \<3.4 mmol/L
HDL \>1.2 mmol/L
77
what is the best drug to decrease LDL?
statins
78
which is the best drug to increase HDL?
niacin
79
which are the best drugs to decrease TGs?
fibrates (gemfibrozil)
80
what are the priorities in treating dyslipidaemia from the cardiovascular risk factor perspective?
1. decrease LDL by \>30% (statins & ezetemibe)
2. decrease TG (fibrates, niacin \> statins)
3. increase HDL (niacin)
81
what is a specific therapy for familial hypercholesterolaemia (type II)?
how does it work?
lomitapide - MTP inhibitor
stops liver from producing VLDL
must be added to low-fat diet and highest possible dose statin
82
what is the difference in the loop of henle between infants and adults?
infants - shorter loop of henle
impaired concentrating capacity, so maximum urine osmolality 700 mOsm
83
which 3 drugs can cause aplastic anaemia?
terrible 3C's:
carbimazole, carbamazepine, chloramphenicol
84
what is the difference between cerebral salt wasting and SIADH?
Cerebral salt wasting (CSW) syndrome occurs after head injury or neurosurgical procedures where a **natriuretic substance** produced in the brain leads to **sodium and chloride loss** in the kidneys, reducing intravascular volume and leading to water retention. There is therefore a **baroreceptor-mediated stimulus** to vasopressin production.
It resembles SIADH in that both are hyponatraemic disorders seen after head injury with *high urinary sodium, urinary osmalility and vasopressin levels*. The
difference is the **_primary event in CSW is high renal sodium chloride loss, not high vasopressin release_**.
85
what is carbohydrate-deficient transferrin?
transferrin is usually a glycoprotein in circulation
alcohol abuse leads to reduced carbohydrate moieties bound to the protein, which can be measured
It is a 70% sensitive, 95% specific test for alcohol abuse
86
what does rasburicase do? when do you use it?
recombinant urate oxidase
use in the setting of chemotherapy to prevent hyperuricaemia in tumour lysis syndrome
87
what does probenecid do?
increases renal excretion of uric acid (uricosuric agent)
mechanism - blocks oraganic acid transporter (OAT) in nephron, inhibiting uric acid resorbtion from lumen
use to prevent cidofovir nephropathy
88
which diuertic class increases the chance for gout?
thiazides
89
what is the biochemical picture in osteroporosis?
none
unless acute #, then raised ALP
90
neonate: born with cataracts, poor feeding, lethargy, conjugated
hyperbilirubinaemia with hepatomegaly and reducing sugars
galactosaemia/carbohydrate metabolism disorders
91
failure to thrive in the first few months, bloody stool, lethargy and jaundice. A distinctive cabbagelike odour is characteristic. On examination there is hepatomegaly with signs of liver failure and subsequent survival for less than 12 months if untreated
urinary succinylacetone is positive
tyrosinaemia
92
test for PKU?
blood Phenylalanine
93
immune reactive trypsin tests for what disease?
cystic fibrosis
94
a common cause of cot death in infants screened for on newborn screening? what is the mechanism?
MCAD deficiency
put baby down to sleep for long night and cannot break down fats it has been storing so dies from hypoglycaemia during overnight fast
95
early lens dislocation, thromboembolism and mental retardation...
suggests what inherited disorder of metabolism
homocysteinuria
96
hyperammonaemia and respiratory alkalosis...
what group of disorders should you think of?
FIRST think of poisoning and drug toxicity...
then **urea cycle disorder**
97
hyperammonaemia with metabolic acidosis (not lactate)...
what group of disorders should you consider?
organic aciduria
also lethargy, truncal hypotonia with limb hypertonia, myoclonic jerks
**unusual odour**
98
hypoketotic hypoglycaemia...
what sort of disorders should you consider?
mitochondrial fatty acid oxidation disorders
also... hepatomegaly and cardiomyopathy
99
what are the lab tests for fatty acid oxidation disorders?
blood ketones - low
urine organic acids
blood spot acylcarnitine profile
100
what are children with carbohydrate metabolism disorders at most risk for?
*E. coli* septicaemia
101
what are the investigations in mitochondrial disorders?
lactate - eleveated after periods of fasting
CSF - lactate, pyruvate, protein
CK
muscle biopsy for ragged red fibres
mitochondrial DNA
