Transcript Clinical Biochemistry

Clinical Biochemistry
FAQ for GP Trainees
Dr Mourad Labib
Consultant Chemical Pathologist
DGOH NHS Foundation Trust
July 2009
Plan

Common scenarios

How best to investigate common
problems

Gold Standard investigations

Advances in Clinical Biochemistry
Case 1
A 58-yr old woman with a 5-year history of diabetes (on
metformin, simvastatin, ACEI and bendroflumethiazide). She
stopped smoking 3 years ago.
Mar 09
Sodium
potassium
Urea
Creatinine
134
4.8
3.9
77
What next?
Scenario 1
•
•
•
•
•
Look at urea
Look at previous results
Look at her medications
Look for weight loss or coughing
Check BP for postural drop
Sodium
potassium
Urea
Creatinine
Low
Chronic
On Citalopram
No
133/82 & 136/79
Mar 09
Oct 08
Mar 08
134
4.8
3.9
77
137
4.6
4.2
82
135
4.3
4.1
79
Mild SIADH secondary to Citalopram
Further investigations: Serum and urine osmolality & sodium
Scenario 2
•
•
•
•
•
Look at urea
Look at previous results
Look at her medications
Look for weight loss or coughing
Check BP for postural drop
Sodium
potassium
Urea
Creatinine
Mar 09
Dec 08
134
4.8
3.9
77
141
4.6
4.2
82
Low
Acute
ACEI
Yes
133/82 & 136/79
?SIADH secondary to bronchial carcinoma
Further investigations: Urgent chest x-ray
Scenario 3
•
•
•
•
•
High
Trend
bendroflumethiazide
dizziness
Look at urea
Look at previous results
Look at her medications
Look for symptoms
Check BP for postural drop
Sodium
potassium
Urea
Creatinine
118/76 & 105/65
Mar 09
Dec 08
134
5.2
7.9
77
137
4.8
7.2
82
Salt loss: D&V, diuretics, ??Addison’s
Further action: consider stopping diuretic, ?synacthen test
Case 2
A 61-yr old man with hypertension on Irbesartan (150 mg
O.D.) and simvastatin.
Sodium
Potassium
Urea
Creatinine
e-GFR
Jan 09
Mar 09
141
4.8
5.9
85
84
143
4.6
6.3
94
75
Does he have CKD?
Is the change in e-GFR significant?
Case 2
• Does he have CKD?
Check for haematuria & ACR
• Is the change in e-GFR significant?
Sodium
Potassium
Urea
Creatinine
e-GFR
Jan 09
Mar 09
141
4.8
5.9
85
84
143
4.6
6.3
94
75
Advised
to have
blood test
after
avoiding
meat the
night
before
Jun 09
140
4.4
5.7
83
87
Serum creatinine can vary by 10 umol/L and can be affected by diet
Case 3
A 68-yr old man presented with tiredness and dry cough.
Medical conditions: IHD, hypertension and osteoarthritis (BB,
aspirin, ACEI, atorvastatin)
Mar 09
Sodium
Potassium
Urea
Creatinine
e-GFR
143
6.4
6.9
97
71
What next?
Case 3
•
•
•
•
Look at urea, creatinine and sodium
Look at previous results
Look at FBC
Check time of collection and receipt
at laboratory
Normal
Normal
Normal
5 hours
Mar 09 Nov 08
Sodium
Potassium
Urea
Creatinine
e-GFR
143
6.4
6.9
97
71
141
4.7
6.5
93
74
Most likely cause: delay in separation
Further action: repeat in plasma and serum ensuring no delay
Case 3
• Advise patient to go to RHH for repeat
• Ensure that you put on request form ‘Plasma potassium’
Sodium
Potassium
Urea
Creatinine
e-GFR
Serum
Plasma
143
5.4
6.7
93
74
142
4.9
6.6
94
74
Case 4
A 49-year old man on simvastatin 40 mg daily for 2 years for
primary prevention (10-year CVD risk was 22%). He
complained of non-specific muscle aches and pains and
his CK was raised 336 IU/L (0-190).
Question:
Do I stop the statin?
Case 4
• Look at previous CK results
Not done
• Check for activity/exercise
✔
• Stop statin and repeat CK after 4 weeks
✔
He takes part in a walking group (walks 7 miles on Mondays and
Thursdays every week)
Four weeks after stopping simvastatin, his CK is 290 IU/L
Raised CK is associated with his exercise and not a side effect of simvastatin
Action: Re-introduce simvastatin
When checking his CK, do it at least 2 days from the walk!
Case 4

Genuine increase in CK as a side effect of statin therapy is
very rare and generally occurs with maximum doses (80
mg daily)

Mild/moderate increase in CK is generally due to the level
of activity/occupation of the patient

Many people at middle-age have non-specific aches and
pains

If a patient is on a lifelong treatment of any drug, he/she is
bound to have unrelated symptoms during treatment!
Case 5
A 55-year old woman presented with thirst and polyuria.
Urinalysis showed glucose ++
FPG
HbA1c
8.8 mmol/L
8.1%
ALT
ALP
Bili
84 IU/L
92 IU/L
14 umol/L
Question: Can I start her on simvastatin?
Case 5
• Mild/moderate increases in ALT and GGT are not
uncommon in newly diagnosed diabetes due to fatty
liver
Action: Start simvastatin
Check LFTs after 6-8 weeks
After 8 weeks
FPG
HbA1c
8.8
8.1%
7.6
7.4%
ALT
ALP
Bili
84
92
14
55
88
13
Case 6
A 62-yr old Asian woman presented with aches and pains,
nausea and heartburn. She had an episode of upper
abdominal pain a week before.
ALT
ALP
Bilirubin
Albumin
49 (7-56)
156 (40-120)
21 (3-22)
39 (35-47)
What next?
Case 6
• Raised ALP could be of bone or liver origin
• Possibilities: Osteomalacia (Asian with aches & pains)
Cholelithiasis (abdominal pain, nausea)
Action: Check GGT and Bone ALP
Scenario 1
ALP
149 (40-120)
GGT
98 (10-58)
Bone ALP 52 (<60)
U/S liver
Scenario 2
ALP
149 (40-120)
GGT
38 (10-58)
Bone ALP 98 (<60)
Serum Vit D
Case 7
A 65 yr old woman presented with back pain for 2 months.
She has hypertension and mild CCF. She has a past history of
breast cancer. She is on Bendroflumethiazide, rosuvastatin
and furosemide.
Calcium
2.74 (2.1-2.6)
Phosphate 0.82 (0.80-1.40)
ALP
96 (40-120)
Albumin
46 (35-47)
What next?
Scenario 1
•
•
•
•
Chronic
No
Normal
Yes
Look at previous results
Check for weight loss
Look at FBC and ESR
Check for history of renal stones
Calcium
Phosphate
ALP
Albumin
PTH
Mar 09
Nov 08
Feb 08
2.74
0.82
96
46
2.62
0.91
88
41
2.67
0.87
92
42
Apr 09
2.71
0.82
87
40
9.5
(1-5)
Most likely cause: primary hyperparathyroidism
Further action: repeat serum calcium with PTH (fasting and no tourniquet)
Scenario 2
•
•
•
•
Look at previous results
Check for weight loss
Look at FBC and ESR
Check for history of renal stones
Calcium
Phosphate
ALP
Albumin
PTH
Mar 09
Nov 08
Feb 08
2.74
0.82
96
46
2.42
0.91
88
41
2.44
0.87
92
42
Normal
Yes
High ESR
No
Apr 09
2.82
0.82
87
37
<1.0
(1-5)
Most likely cause: malignancy
Further action: repeat serum calcium with PTH (fasting and no tourniquet)