General Things Flashcards
What are the 3 types of interferon, what cells are they produced by and what is their main action?
What are they used to treat?
Interferon alpha, beta and gamma
Alpha - leucocytes, antiviral and some anti-cancer
Beta - fibroblasts, antiviral action
Gamma - NK cells, macrophage activation and weak antiviral action
Alpha - hep B&C, kaposi sarcoma, renal cell cancer (SE: flu-like reaction and depression)
Beta - MS, reduces frequency and severity of relapses
Gamma - chronic granulomatous disease and osteoporosis
Daily fluid requirements?
Na, Cl and K?
Glucose?
25-30 ml/kg/day water
1 mol/kg/day of Na, Cl and K
50-100g glucose/day (to limit starvation ketosis if fasting)
Does the amount of glucose prescribed in fluids change based on the patient’s weight?
No
Specific risks associated with prescribing saline?
Hartmann’s?
Hypercloraemic metabolic acidosis
Contains K so do not use in patients with/at risk of hyperkalaemia
How to work out anion gap in metabolic acidosis?
Na - (Cl+HCO3), normal range = 4-12
OR
(Na+K) - (Cl+HCO3), normal range = 10-18
Causes of anion gap metabolic acidosis?
MUDPILES CAT
Methanol Urea DKA Paraldehyde Iron/Isoniazid Lactate Ethanol Salicylates
Carbon monoxide
Aminoglycosides
Theophylline
Causes of normal anion gap metabolic acidosis?
HARDASS
Hyperalimentation (TPN feeds) Addison's disease Renal tubular acidosis Diarrhoea Acetazolamide Spironolactone Saline infusion
How to work out maintenance fluid replacement for a kid?
100ml/day for every kg 0-10kg
50ml/day for every kg 11-20kg
20ml/day for every kg >20kg
Max rate of K infusion via peripheral line?
10mmol/hour
Any higher than 20mmol/hr needs cardiac monitoring
Shock with warm peripheries?
Neurogenic shock
From loss of sympathetic or hyper-parasympathetic innervation - marked vasodilation
Allograft?
Isograft?
Autograft?
Xenograft?
Allo - to a non-identical relative
Iso - between identical twins
Auto - within yourself
Xeno - to another unrelated person
7 P450 enzyme inducers?
Phenytoin Carbamazepine Rifampicin Phenobarbitone St John's Wort Chronic alcohol intake Smoking (smokers need to take more aminophylline)
12 P450 inhibitors?
Ciprofloxacin and erythromycin Isoniazid Cimetidine Omeprazole Amiodarone Allopurinol -azole antifungals Fluoxetine and Sertraline Valproate Acute alcohol intake
As bisphosphonates take around 3 days to work (7 days for maximal effect), what else can be used acutely?
Advice for long term management of hypercalcaemia in malignancy?
Calcitonin Steroids (sarcoidosis)
Diuretics - esp in patients who cannot tolerate aggressive fluid resuscitation
Long term:
- Increase fluid intake
- No need to have low Ca diet (as gut absorption usually reduced)
Why is hyperkalaemia usually associated with acidosis?
K and H are competitors - as K levels rise fewer H ions can enter the cell
Causes of hypokalaemia with alkalosis?
- vomiting
- thiazide/loop diuretics
- Cushing’s syndrome
- Conn’s syndrome (primary hyperaldosteronism)
Causes of hypokalaemia with acidosis?
- Diarrhoea
- renal tubular acidosis
- acetazolamide
- partially treated DKA
Deficiency of what other mineral can cause K deficiency?
Mg
Drugs which can cause SIADH?
Carbamazepine Sulfonylureas SSRI's Tricyclics Vincristine
What malignancy can cause SIADH?
Small cell lung cancer
also pancreas and prostate
Neurological causes of SIADH?
Stroke
SAH
Subdural haemorrhage
Meningitis/encephalitis/abscess
Infections which cause SIADH?
TB
Pneumonia
Can PEEP cause SIADH?
Can porphyrias cause SIADH?
Yes
Yes
Management of SIADH?
Slow correction to avoid central pontine myelinosis
Fluid restriction
Demeclocycline: reduces responsiveness of collecting tubule cells to ADH
Captains (ADH antagonists)
Causes of hyperkalaemia?
AKI Drugs - spironolactone, ACEI, ARB, ciclosporin, heparin/LMWH, B blockers Metabolic acidosis Addison's Rhabdomyolysis Massive blood transfusion
Food:
- salt substitutes (contain K instead of Na)
- bananas, oranges, kiwi, avocado, spinach, tomato
In acute pancreatitis what happens to:
- glucose?
- K?
- Ca?
- Mg?
Hyperglycaemia
Hypokalaemia (vomiting)
Hypocalcaemia
Hypomagnesaemia (vomiting)
Causes of hypocalcaemia?
- VitD deficiency (osteomalacia)
- CKD
- hypoparathyroidism
- Pseudohypoparathyroidism
- Rhabdomyolysis
- Mg deficiency
- Massive blood transfusion
- acute pancreatitis
Blood samples contaminated with EDTA give falsely low Ca
Acute management of severe hypocalcaemia?
IV Ca gluconate
10ml, 10% over 10 mins
ECG monitoring
Further management depends on cause
Causes of hypernatraemia?
Management?
Dehydration
Osmotic diuresis (e.g. HHS)
Diabetes insipidus
Excessive saline
Correct hypernatraemia slowly and cautiously, can predispose cerebral oedema and seizures
General rate is no greater than 0.5mmol/hour
What are the general causes of hyperuricaemia?
What can cause increased synthesis of urea?
Decreased excretion?
Increased cell turnover or decreased renal excretion of uric acid
Increased synthesis:
- Myeloproliferative disorders
- Exercise
- Cytotoxics
- Psoriasis
- Lesch-Nyhan disease
- Diet rich in purines
Decreased excretion:
- Drugs: low-dose aspirin, diuretics, pyrazinamide
- pre-eclampsia
- alcohol
- renal failure
- lead
2 main causes of hypokalaemia with hypertension?
Cushing’s syndrome
Conn’s syndrome
Raised ALP and raised Ca?
Bone mets
Hyperparathyroidism
Raised ALP and low Ca?
Osteomalacia
Renal failure
Generally, what is reabsorbed in kidney?
Na, Ca, Cl, Mg H2O HCO3 Glucose AA
Generally, what is excreted in kidney?
K, H, urea
Creatinine
Where do PTH and aldosterone work?
PTH proximal part of distal convoluted tubule (same as thiazides)
Aldosterone distal part of distal convoluted tubule (same as spironolactone)
H1 antagonist antiemetic examples?
MOA?
What are they esp good for?
SE?
- Cyclizine, promethazine, diphenhydramine
- Block H1 receptors in brain
- Motion sickness
- Sedation
Antimuscarinic antiemetic example?
MOA?
Esp good for?
SE?
Hyoscine (scopolamine)
- Block muscarinic M1 ACh receptors in brain
- Motion sickness
- Dry mouth, tachycardia, constipation
5-HT3 receptor antagonist antiemetic examples?
MOA?
SE?
- Ondansetron
- Block 5-HT3 receptors in the CTZ in the medulla, as well as same receptors in GI tract
- Constipation, diarrhoea, headache
Dopamine antagonist antiemetic examples?
- Chlorpromazine, haloperidol, prochlorperazine, metoclopramide, domperidone
- D2 antgonists in the CTZ of the medulla (except domperidone) and also the GI tract
- SE: diarrhoea, EPSE (except domperidone)
NK1 antagonist amtiemetic examples?
Blocks NK1 receptors in the GI tract and CTZ blocking the effects of substance P (which evokes vomiting)
SE: constipation, headaches
Antidiarrhoeal drug examples?
MOA?
SE?
- Main thing is electrolyte replacements
- Loperamide, diphenoxylate
- bind mu-opioid receptors in GI tract (less of an effect on the brain)
- SE: constipation, sedation, respiratory depression
Laxative examples?
Lspaghula husk - bulk forming
Lactulose - osmotic - hepatic constipation
Senna - stimulant purgative - increases electrolyte/water secretion
Hyponatraemia causes with urinary Na >20mmol/L?
Sodium depletion/renal loss (often hypovolaemic):
- diuretics: thiazides, loops
- Addison’s
- renal failure
If patients euvolaemic:
- SIADH (urine osmolality often >500mmol/kg)
- Hypothyroidism
Hyponatraemia causes with urinary Na <20mmol/L?
Sodium depletion/extra-renal loss:
- diarrhoea, vomiting, sweating
- burns
- rectal adenoma
Water excess (often hypervolaemic and oedematous):
- secondary hyperaldosteronism (HF, cirrhosis)
- nephrotic syndrome
- IV dextrose
- psychogenic polydipsia
Causes of hyperlipidaemia which result in predominant hypercholesterolaemia?
What is predominantly raised in the other causes?
High cholesterol:
- nephrotic syndrome
- cholestasis
- hypothyroidism
Other things cause hypertriglyceridaemia (diabetes, obesity, alcohol, thiazides, unopposed oestrogen, liver disease)
Management of acute hyponatraemia (<48 hours)
Typically hypertonic saline (3%) is given - can correct more quickly than in chronic as less risk of demyelination
Management of chronic hypovolaemia if:
- hypovolaemic cause (renal failure, diuretics, addison’s)?
- euvolaemic cause (SIADH)?
- hypervolaemic cause (HF, liver failure, nephrotic syndrome)?
Hypovolaemic: 0.9% saline
Give as trial initially, if Na falls then likely alternative diagnosis such as SIADH
Euvolaemic: fluid restrict to 500ml/day. Consider demeclocycline/vaptans
Hypervolaemic: fluid restrict to 500ml/day. Consider loop diuretics/vaptans
Complication of correcting sodium too quickly?
Rate it should be done?
Symptoms of complication?
Central pontine myelinosis
Na+ level raised by 4-6mmol/L each day
Symptoms appear after 2 days:
- dysarthria, dysphagia
- paraparesis/quadraparesis
- seizures, confusion, coma
- locked in syndrome
Indications for cyclizine?
Indications:
Central causes nausea
Movement related
Bowel obstruction
Indications for Dexamethasone as antiemetic?
Intracranial disease
Bowel obstruction
Indications and contraindications for domperidone antiemetic?
Indications:
Gastric stasis
Parkinson’s - doesn’t cross BBB
Contra:
Bowel obstruction
Indications and contraindications for metoclopramide antiemetic?
Indications:
gastric stasis
Contra:
Not in parkinson’s
Not in bowel obstriction
Indications and contraindications for haloperidol as anti-emetic?
Chemical causes e.g. opioid
Metabolic causes
Indications and contraindications for lorazepam as antiemetic?
Anxiety-related
Indications and contraindications for ondansetron antiemetic?
chemo-induced
Causes of hypophosphataemia?
Alcohol excess Acute liver failure DKA Refeeding syndrome Primary hyperparathyroidism Osteomalacia
Consequences:
- RBC haemolysis
- WCC and platelet dysfunction
- Muscle weakness and rhabdomyolysis
- CNS dysfunction (resp depression etc)
When is a 150ml bolus of 3% NaCl typically given?
Acute hypovolaemia Na <120
