short case meds and metabolic Flashcards
clexane for DVT/PE + renal dosing prophylactic and treatment
Normal dosing
prophylactic - 40mg /24 hr
treatment
- 1.5mg /kg /24hr
high risk (obesity/symptomatic, cancer) 1mg/kg/BD
renal dosing eGFR <30
- prophylactic - 20mg/ day
- treatment 1mg up to 100u /kg /day
treatment of GCA
If suspected do ESR then
1. Prednisone 1mg/kg po daily for 4 weeks.
Then taper over 6-12 months with symptoms / ESR improvement
- If visual/ neuro symptoms 1. Prednisolone IV 1g for 3 days
- If confirmed - aspirin 75mg daily
- consider bone protection - VIt D, BP
What can you prescribe for constipation Non pharm, prophylactic and oral
Non pharm
1. regular toileting, increased dietary fibre, hydration and mobilisation
Prophylaxis
1. Stimulant + softener taken regular
eg. Docusate sodium (softener) + sennoside B (peristalsis stimulator)
= Laxsol 1-2 tab at night up to 4 tabs
NB cannot use stimulants in bowel obstruction
- Molaxole or lactulose (osmotic agents) added
NB avoid softeners in spinal cord compression
- Rectal interventions
- manual evacuation of faecal impaction
If soft faeces: Microlette (sodium citrate osmotic enema)1-2 daily ( osmotic ) OR 1-2 Bisacodyl suppository (stimulant)
If hard faeces: 1-2 Bisacodyl suppository (stimulant)
+/ or 1-2 glycerol suppository (osmotic)
or microlette (osmotic)
Then
Rectal phosphates - Fleet enema (saline laxative)
what can you prescribe for nausea -moa, indication, SE, CI
1.Dopamine receptor antagonist (upper GI prokinetic) for general n+v
-Metoclopramide 10mg TDS PO/IV/SC :
Contra: GI obstruction/haemorrhage/parkinsons
-SE: extrapyramidal, drowsiness, restlessness, acute angle glaucoma. Note doses reduced in renal and hepatic impairment
- Domperidone -10mg TDS - dopamine receptor antagonist. CI: prolactinoma, GI obstruction, per or haemorrhage, long QT
-SE less central effects, dry mouth
- avoid in mod to severe hepatic impairment and reduce frequency in renal impairment - Antihistamine
Cyclizine 25-50mg TDS - h1 receptor antagonist with central anticholinergic effects. Good for n+V, vertigo and motion sickness
CI: GI obstruction, severe HF, severe Liver disease, acute porphyria
SE: sedation, anticholinergic, extrapyramidal, hypotension with IV, arrhyhthmia s
- not for severe liver disease - 5HT3 antagonist
eg. Ondansetron 4-8 mg BD . Good for post op and chemo/radiotherapy nausea
CI : long QT, hypokalaemia, hypomagnesmia, serotoninergic drugs
SE: constipation, flushing, headache
Max 16 per day in hepatic impairment - Dopamine antagonist (phenothiazine). N+V related to vertigo, radiation, neoplastic disease, opioids, anaesthetics, cytotoxics
Prochlorperazine 5mg BD/TDS PO or 3-6mg buccal BD
CI ; CNS depression, phaeochromocytoma, long QT
SE: extra pyramidal, anticholinergic, acute angle glaucoma
Start low in renal impariment and liver disease - Haloperidol 0.5-3mg PO/SC
Centrally acting sedative used in pall care good for opoid induced N+V , renal failure, hypercalcaemia
CI: parkinsons
what can you prescribe for pain
- paracetamol 0.5-1g Q4-6hourly max 4g daily
- NSAID - consider not long term GI bleeding, severe heart failure, pregnancy
- ibuprofen (200-400mg 2-4 times daily max 2.4 g daily
- celecoxib (selective COX 2 - less GI - 200-400mg daily in 1-2 divided doses
+/- PPI - omeprazole 20mg daily for 4 weeks if bleed
- Weak Opioids
-Tramadol 50-100mg BD + prochlorperazine 5mg BD
-Codeine 30-60mg Q4H max 240mg + Laxsol 1-2 tabs nocte - swap the opioids to Strong opioids + antiemetic+ laxative
- Morphine 5-10mg Q4H adjusted to response
first SA severidol every 4 hours, then BD modified release M-eslon
Oxycodone or Fentanyl when renal failure - po, IV , SC
2x morphine strength
OxyNorm (IR) 5mg Q4-6h
Oxycontin (MR) 10mg every 12 hours
Fentanyl via protocol
Provide PRN dose and review daily to see if prescribed doses accurate
- Adjuvants for neuropathic pain
a) TCA: SE: dry mouth, blurred vision
b) gabapentin or pregabalin: SE drowsiness, dizziness, ataxia - adjuvants for bone/ met pain, spinal pain, liver mets
Dexamethasone - Adjuvants for spasticity pain in MS, spinal cord, Baclofen 5mg TDS
what can you prescribe for DKA
- ABCD - secure 3x IV lines
- IV fluids within 30min - 0.9% NaCl 1000ml first hour, 500 mL per hour next 4 hrs.
- Add K+ per L of fluid depending on serum K
- at least 70 mmol in the first 24 hours - cardiac monitoring needed if infusion K+ rate >10mmol> hr - Insulin infusion units/hour based on schedule within 60 minutes
- Investigations
- VBG - bicarb
- U&E, Cr, Bhb, lactate
- Urinalysis, BC and CXR
-ECG
===Repeat serum K on VBG 3 times in first 24 hours
- FBC - Monitor vitals, fluid balance -?urinary catheter, NG.
6.Start Glucose Infusion when BG <13mmol - start sub cut insulin when pt well hydrated. VBG >7.35, and give insulin before next meal, discontinue insulin infusion 2 hours post meal
What are the presentations, investigations and management for hyperkalaemia (K= >6.5 mmol) - danger is VF
Presentation - fast irregular pulse, chest pain, palpitations, dizziness
Causes: renal failure, metabolic acidosis (secondary to sepsis, volume) K+ sparing diuretics (spironolactone) rhabdomyolysis, metabolic acidosis, burns, artefactual result
Ix
U+E, ECG, renal function
ECG : tall, tented T waves. Wide QRS which becomes sinusoidal then VT/ VF , flat p waves
Treatment
1.start ECG put on telemetry
2. SA insulin 10u + 50mL 50% dextrose over 10 minutes
+ 5 mg salbutamol nebulised hourly
3. Give calcium gluconate 10% injection over 10 minutes and titrating to ECG improvement
4. For acute case stop ACE and arbs. Stop any fluids with K+.
5. Assess fluid status and treat accordingly
6. Calcium resonium (-K+ binder in the gut) + lactulose
7. Increase K+ elimination - K+ losing diuretic = furosemide. Consider dialysis if not correcting
7. Fix underlying problem - treat acidosis with oral bicarb 840mg 2-3 BD or IV bicarb 8.4% 50mL over 2 hours and repeat
how do you interpret anaemia tests
- Hb
- high reticulocytes = haemolysis or post haemorrhage
NORMAL RETICs - Microcytic = do iron studies to differentiate
- iron deficiency (decreased everything, increased/normal TIBC)
from
- anaemia of chronic disease (ferritin increased , everything normal or decreased) or
- haemoglobinopathies (increased/normal ferritin everything) - macro = do TSH and folate/B12 - hypothyroidism, renal failure, myelodysplasia
- Normocytic anaemia can be mixed picture - do Cr, CRP, folate B12 + other tests looking for all macro and micro except for iron deficiency
What are the considerations for someone on long term steroids - SE, stress dosing, interactions, prophylactic needs
SE:
- weight gain, skin thinning,
- GI ulceration
-HTN
Muscle weakness
Immunosuppression
DM
Bone loss / increased # risk
Stress dosing in illness
- 2x regular dose for duration of illness/surgery/ flare and then gradually reduce
eg. IV 50-100mg hydrocortisone Q6-8h if severe flare.
Interactions: with NSAIDS/ warfarin to cause hypokalaemia
Prophylactic: vit D/bisphosphanates for those at risk of fracture
Physical activity. start low, go topical if can
What are the SE and contraindications of NSAIDS
GI bleeding - CI in aspirin, active GI ulcers
Renal impairment
CI in heart failure, increased risk of MI and stroke especially with smoking + drinking
Causes of hyponatraemia and how do you investigate/ manage
Signs of hyponatraemia = n+v, headache, confusion, seizures , oedema
- Hypervolaemic: nephrotic syndome HF, cirrhosis, RF
- Loop diuretics - monitor - Euvolaemic: do urine osmolality - if >300 than SIADH, if not then water intoxication, severe hypothyroidism, glucocorticoid insuficiency
Treatment for SIADH is r/v meds, fluid restrict
- Hypovolaemic: check urine Na+.
- If >20 then due to renal na+ loss in addisons, renal failure, diuretics, osmotic diuresis
- If no then loss by v+d, fisutale, burns, SBO, sweat
Treatment: IV 0.9% saline slowly - don’t increase Na more than 15mmol/L per day for central pontine myelinolysis
Hypernatremia treatment and cause and signs
signs: lethargy, thirst, confusion, coma, dehydration.
Causes: fluid loss (d+v+ burns), diabetes insipidus, iatrogenic (too much IV fluids)
Management is
- oral water if possible
Or IV glucose 5% slowly +
0.9% saline if hypovolaemic
Correction should not exceed 10-12 mmol per day
Meningitis ix and treatment
- Blood cultures
- Screen for encephalitis - GCS <14, seizures, altered behaviour, focal neurology
- Red flags - shock, sepsis, purpuric rash - IVabx immediately , call ID and ICU
IV ANTIBIOTICS
1. dexamethasone 10mg IV Q6H - discuss with ID after 4 hrs
2. Ceftriaxone 2g IV Q12H
- if immediate or delayed severe reaction - d/w OC ID or if cant then
- Vancomycin as per vanculator and aztreonam 2gIV and discsus
3. If risk factors for listeria eg. immunocompromise, >50. alcohol, pregnant then add benzylpenicillin 2.4g IV Q4H as resistant to ceph
4. If risk factors for s. pneumoniae (hospitalisation, sinus disease, frequent abx treatment, contact with daycare children) - Add Vancomycin
- CT head if neurology, papilloedema, >60yo, immunocompromise
- If no raised ICP then LP within 30 minutes or abx
- CSF analysis,
- gram stain and culture , PCR for enterovirus and HSV
- cytology
- rbc, WCC, protein,
- ZN stain for acid fast bacilli
- oligoclonal bands - Review results
bacterial - gram stain Or WCC >100 + polymorphs >50% or protein >0.5, <2.8 glucose
aseptic - nil on gram stain + WBC 5-230, lymphocytes >505
What medications prolong QT interval, what is QT interval (Q wave to T end (period of ventricular systole to relax)
QT prolongation is dangerous as associated with Torsades de Points and VT/F / sudden cardiac death
QT interval corrected is estimation of QT interval at standard HR of 60 bpm. Formulas use the QT / square root of RR interval in seconds
QTc prolonged if >440ms in men, or 460ms in women.
Associated with
Drugs
Antipsychotics, antiarrhythmics, TCA, antidepressants, Antihistamines, hydroxycholoroquines, macrolides
- hypokalaemia
- hypomagnesmia
- hypocalcaemia
-hypothermia
- MI
- raised ICP
How to interpret TFT - primary and secondary hypothyroidism, primary and secondary hyper
T3 is the active form, but majority release is T4 gets converted into T3 peripherally and is a negative feedback to the pituitary and hypothalamus
1’ hypothyroid eg. autoimmune thyroiditis, iodine deficiency, radiotherapy,
= reduced thyroid hormone secretion = low T4 and T3, raised TSH
2’ hypothyroid - rare - reduced TSH - from pituitary adenoma
= normal / low TSH due to lack of production
Low T4
1’ hyperthyroidism eg. Graves, toxic multinodular goitre,
= raised T3/4, low TSH
2’ hyperthyroidism
- TSH secreting tumour, HcG tumour
Raised T3/4 and raised TSH
