Therapeutic Drug Monitoring, Calcium, Enzymes and Cardiac Markers Flashcards
Phenytoin
- used to treat?
- signs of toxicity?
- Seizures
- Ataxia and nystagmus
Phenytoin
- interactions and cautions?
- treatment?
- At high levels liver becomes saturated -> surge in blood levels
- Omit/ reduce dose
Digoxin
- used to treat?
- signs of toxicity?
- Arrythmias
- Arrythmias, heart block, confusion, xanthophsia (seeing yellow)
Digoxin
- Interactions and cautions?
- Treatment?
- Levels increased with hypokalaemia. Reduce dose in renal failure and in elderly
- Digibind AKA Digoxin immune Fab
Lithium
- used to treat?
- Signs of toxicity?
- Mood disorders eg bipolar
- Tremor (early), lethargy, fits, arrhythmia, renal failure
Lithium
- Interactions and cautions?
- Treatment?
- Excretion impaired by hyponatreamia, decreased renal function and diuretics
- Renal failure may need heamodialysis
Gentamicin
- Used to treat?
- Signs of toxicity?
- Infection
- Tinnitus, deafness, nystagmus, renal failure
Gentamicin
- Interactions and cautions?
- Treatment?
- Mostly use single daily dosing. Monitor peak and trough level before next dose
- Omit/ Reduce dose
Theophyline
- Used to treat?
- Signs of toxicity?
- COPD, Asthma - Bronchodilator
- Arrythmias, anxiety, tremor convulsions
Theophyline
- Interactions and cautions?
- Treatment?
- Variation in 1/2 life; e.g. 4hr for smokers, 8hrs for non smokers, 30hrs in liver disease. Level increased by erythromycin, cimetidine and phenytoin
- Omit/ Reduce dose
Normal range for Calcium and body composition? (can’t think of the correct way of saying it)
- 2-2.6mmol/l
- 45% isonised (free- biologically active form)
- 50% bound to albumin, therefore affected by albumin level- use corrected calcium
What are the two main hormones involved in calcium metabolism?
PTH
1,25 (OH)2D - Calcitriol
PTH - Parathyroid Hormones - how does it have its effects?
- Increases tubular 1alpha hydroxylation of vitamin D (25(OH)D) leading to increased intestinal absorption via calbindin
- Mobilises calcium from bone
- Increase renal calcium reabsorption
- Increase renal phosphate excretion
1,25 (OH)2D - Calcitriol -how does it have its effects?
- Increase calcium and phosphate absorption from the gut
- Bone remodelling
Disorders of Calcium Balance
- Primary Hyperparathyroidism
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Increase in PTH (80% parathyroid adenoma)
- Ca = HIGH
- PO4 = LOW
- PTH = HIGH/NORM
- Alk Phos = HIGH/NORM
- Vit D = NORM
Disorders of Calcium Balance
- Secondary Hyperparathyroidism
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Renal Osteodystrophy
- Ca = LOW/NORM
- PO4 = HIGH
- PTH = HIGH
- Alk Phos = HIGH
- Vit D = NORM
Disorders of Calcium Balance
- Tertiary Hyperparathyroidism
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Autonomous PTH secretion post renal transplant
- Ca = HIGH
- PO4 = LOW
- PTH = HIGH
- Alk Phos = HIGH/NORM
- Vit D = NORM
Disorders of Calcium Balance
- Hypoparathyroidism
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Low levels of PTH. Primary = DeGeorge Syndrome. Secondary = Post Thyroid Surgery
- Ca = LOW
- PO4 = HIGH
- PTH = LOW
- Alk Phos = LOW/NORM
- Vit D = NORM
Disorders of Calcium Balance
- Rickets/ Osteomalacia
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Vitamin D deficiency
- Ca = LOW
- PO4 = LOW
- PTH = HIGH
- Alk Phos = HIGH
- Vit D = LOW
Disorders of Calcium Balance
- Paget’s Disease
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Re-modelling of bone
- Ca = NORM
- PO4 = NORM
- PTH = NORM
- Alk Phos = HIGH
- Vit D = NORM
Disorders of Calcium Balance
- Osteoporosis
- primary defect?
- Ca, PO4, PTH, Alk Phos, Vit D levels?
- Bone loss
- Ca = NORM
- PO4 = NORM
- PTH = NORM
- Alk Phos = NORM
- Vit D = NORM
Causes of Hypercalcaemia with High Albumin?
Urea high = Dehydration
Urea normal = Cuffed (left the tourniquet on too long when taking blood)
Causes of Hypercalcaemia with Low/Norm Albumin and Low phosphate?
Primary or Tertiary hyperparathyroidism - confirm with ++ PTH
Causes of Hypercalcaemia with Low/Norm Albumin and High phosphate?
- High ALP (increased bone turnover) - Bone metastasis, Thyrotoxicosis, Sarcoidosis (increased 1alpha OH)
- Normal ALP - Myeloma, Excess Vit D, Sarcoid, Milk alkali syndrome ( + high HCO3)
Symptoms of Hypercalcaemia?
Stones (renal) Bones (pain) Groans (psych) Moans (abdo pain) Polyuria Muscle Weakness
Treatment for Hypercalcaemia?
Correct dehydration
Bisphosphonates
Correct cause e.g. chemo for cancer
Causes of hypocalcaemia with High Phosphate?
Chronic Kidney Disease
Hypoparathyroidism (inc post thyroid surgery)
Pseudohypoparathyroidism
Hypomagnesaemia
Causes of hypocalcaemia with Norm/Low Phosphate?
Osteomalacia
Acute pancreatitis
Over hydration
Respiratory alkalosis (low ionised/active Ca)
Symptoms of Hypocalcaemia?
Perioral paraesthesia
carpopedal spasm
neuromuscular excitability
(Trousseau’s and Chvostek’s sign)
Treatment for Hypocalcaemia?
Mild - Give calcium
Chronic Kidney Disease - Alfacalcidol
Severe - 10% calcium gluconate IV
Risk Factors for Renal Stones
Dehydration , abnormal urine pH (e.g. meat intake, renal tubular acidosis), increased excretion of stone constituents, urine infection (treat infection), anatomical abnormalities
Renal Stones - Calcium Stones
- due to?
- preventative management?
most patients are normocalcaemic
Results from
-Hyperoxaluria - Increased intake, absorption etc
-Hyercalciuria - increased intake, renal leak
Preventative management - avoid dehydration, reduce oxalate intake, maintain Ca intake, thiazides -> hypocalciuric, citrate (alkalinise urine)
Investigations for recurrent Renal Stones
- Serum - Cr, Bicarbonate, Ca, Phosphate, Urate, PTH (if hypercalcaemic)
- Stone analysis
- Spot urine
6 different stone compositions, Frequency and X ray appearance
- Calcium mixed - 45% - Radio-opaque
- Calcium oxalate - 35% - Radio-opaque
- Calcium phosphate - 1% - Radio-opaque
- Tripple phosphate “Struvite” - 10% - Radio-opaque “staghorn calculi” (branching calcific densities overlying the renal outline
- Uric acid - 5% - Radiolucent
- Cysteine - 1-2% - Radiolucent
Amylase levels in pancreatitis?
High serum levels in acute pancreatitis - usually >10x upper limit of normal (normal serum amylase test - 40-140U/L
Creatine Kinase is a marker of? Raised levels due to?
CK is a Marker of muscle damage (CK-MM = Skeletal muscle, CK-MB (1&2) = cardiac muscle)
- raised levels due to
- Physiological - Afro-Caribbean (5x upper limit of normal)
- Pathological - Duchenne Muscular Dystrophy (>10x Upper limit of normal), MI (>10xULN), Statin related myopathy, Rhabdomyolysis
Alkaline Phosphatase - Causes of raised levels?
Present in high concentrations in liver, bone, intestine and placenta
-causes of raised ALP :-
-Physiological - Preganacy (third trimester), Childhood (during growth spurt)
- Pathological
->5xULN = Bone (Pagets, osteomalacia), Liver (Cholestasis, Cirrhosis)
-
Troponin (NOT an enzyme) - Biomarker for?
Myocardial injury biomarker
Measure at 6 hours and then at 12 hours post onset of chest pain, remains elevated for 3-10 days
Diagnostic Criteria for Acute MI
1) Typical rise and gradual fall (troponin) or more rapid rise and fall (CK-MB) with at least one of the following…
- ischemic symptoms
- pathological Q waves on the ECG
- ECG changes indicative of schema
- Coronary artery intervention
2) Pathological findings of an acute MI
