Saturday 1 September 2012

Prevention

The following is mostly a summary of the "Red Book" Guidelines for preventative activities in general practice.

          Screening

Involves conducting tests (questionnaires or lab tests) on patients to work out who is more likely to be helped than harmed by further tests of treatment to reduce the risk of a disease.

          Informed consent

Must be obtained before carrying out any screening test.

For example I saw a patient the other day for a review of results and I had not specifically taken the time to explain what the implications of doing a fasting blood glucose level might be. The result was 14 suggesting that combined with her history and weight that she had undiagnosed diabetes. She was angry and shocked when I told her and has since left the practice. The background of which I was unaware is that her husband has severe type 2 diabetes and she has always said that she would never get it and if she did she would rather die than be on any medication. I could have prevented this by specifically providing pre-test counselling and education about what a diagnosis of diabetes might mean for her.


There are various guidelines which help determine what screening programs are effective. These guidelines deal with
  • The condition
  • The test
  • The treatment
  • The outcome

The condition should be important, it should be recognisable early on (e.g. cervical dysplasia precedes CIS).
The test should be simple, safe and validated.
There disease must be treatable by a means that is agreed upon and effective.
Screening should result in an outcome of reduced morbidity and mortality.

Patient education is important in helping patients reduce their risk of developing an illness.
Effective patient education depends on:

  • The GP enquiring about what the patient understands of a condition
  • The patient feeling they can trust their GP
  • Face to face communication
  • The patient being able to be involved in decision making
  • The GP highlighting the benefits and costs of change vs no change
  • Strategies to help the patient remember what you've told them
  • The GP tailoring the information to the patient's interest in change (see stages of change model)

          Stages of Change Model


Remember the dam PC has broken again! (PCDAM)

Pre-contemplation (Mrs Wrinkles smokes 2 packs a day and hasn't even thought of quitting)
Contemplation (Mr Wobbles is beginning to wonder if all the Big Macs might be giving him indigestion. He's looking for information in the Woman's Weekly but isn't ready to take action yet)
Determination (Mr Stoned has lost his job and decided he's sick of his drug habit ruling his life. He's ready to change!)
Action (Mrs Papilloma has made an appointment to have her pap smear and is in the waiting room after not having had one for 10 years)
Maintenance (Sporty Spice is working to keep up her exercise and diet but she needs a bit of encouragement to avoid falling back into her old ways)

Motivational interviewing is about understanding where the patient is at by asking questions and listening and then it is about helping them move from one stage to the next by asking more questions and providing appropriate information. There's no point discussing nicotine replacement or varenicicline with Mrs Wrinkles in the above scenario. You need to ask her about any negative experiences she or anyone else had had by smoking..ask her to imagine what possible negatives there are. Give her some relevant details about the health benefits of quitting etc.

Prevantative activities before pregnancy
Target: Women aged 15 to 49
SNAP PIC

Smoking
Nutrition and folate
Alcohol (and other drugs prescribed and illicit)
Physical Activity, Obesity

Psycho-social support
Immunisations
Co-morbid conditions (including genetic/ family hx and chronic conditions)

Note that women receiving live viral vaccines such as MMR and varicella should be advised against falling pregnant within 28 days of vaccination.

Influenza vaccine is recommended during pregnancy (especialy if they will be in 2nd or 3rd trimester during flu season)

DTP should be considered before conception.

Folate 0.5mg should be started 1 month before pregnancy and continued until 3 months after pregnancy.
High risk for NTD = previous pregnancy affected by NTD, those on anti-epileptics, those who have diabetes: These women should be on 5mg daily folic acid.


 

Sunday 5 August 2012

Hypertension Part 3: When to intervene

High Blood pressure is a major risk factor for cardiovascular disease. None the less it is important to consider any individual risk factor in the context of overall cardiovascular risk.
treatment is influenced by
  • pre-existing vascular disease
  • other risk factors
  • associated conditions (diabetes and renal disease) & target organ damage
Treatment Goals
  • improve long term survival and quality of life
  • reduce blood pressure
  • reduce overall cardiovascular risk
  • minimise end-organ damage

"Remember to remove, revise, or substitude drugs which may be causing hypertension (eg NSAIDs, corticosteroids, oral contraceptives)" Murtagh's General Practice 5th edition.


Individual and population interventions to reduce blood pressure, stroke and vascular disease (From Medicine Today sept 2009 vol 10 number 9 p 62; and Guidelines for the management of absolute cardiovascular disease risk p 39)
  • decrease weight (ideal weight is BMI <25 and waist circ < 94 cm in men (<90 Asian men) and < 80cm in women (including Asian women).
  • physical exercise (minimum 30 mins 5 to 7 times a week)
  • reduce salt < 6 grams a day (= 2300 mg sodium)
  • reduce alcohol (<2 drinks a day and 2 alcohol free days)
  • increase unsaturated fat intake
  • increase fresh fruit and vegetable intake
  • use drug therapy in high risk individuals
  • no smoking 




Immediate treatment to lower blood pressure is recommended in the following situations:
  • Systolic blood pressure 180 mmHg or greater (grade 3 hypertension) and or
  • Diastolic blood pressure 110 mmHg or greater
  • Systolic blood pressure 160 mmHg or greater and diastolic blood pressure 70 mmHg or less (isolated systolic hypertension with widened pulse pressure)
  • Patients with associated conditions (for example, stroke or myocardial infarction) or evidence of end-organ damage (for example, microalbuminuria, left ventricular hypertrophy) also need urgent treatment (see the tables below)
  • Patients assessed as being at "high risk" following 5 year absolute risk assessment
Any pharmacotherapy should always be used in conjunction with lifestyle modification, and management of associated conditions.
 
 

Associated clinical conditions
Diabetes
Ø  > age 60
Ø  With urine ACR >2.5 male or > 3.5 female

Cerebrovascular disease
Ø  Ischaemic or haemorrhagic stroke
Ø  TIA
Coronary heart disease
Ø  MI
Ø  Angina
Ø  Stent/ angioplasty
Chronic heart failure

Chronic kidney disease
Ø  Diabetic nephropathy
Ø  GN
Ø  Hypertensive kidney disease
Aortic disease
Aneurism (dissecting or fusiform)
Peripheral Arterial Disease
Clinically or ABI < 0.9
Hypercholesterolaemia
>7.5 total
Family history of:
Premature cardiovascular disease
Previous diagnosis of:
Familial hypercholesterolaemia


End Organ Disease
LVH
Diagnosed on ECG or echo (see previous blog)
Microalbuminuria

Chronic kidney disease
Presence of either
Ø  Proteinuria
Ø  eGFR < 60
Vascular disease
Ø  Atherosclerosis evident on ultrasound or radiology
Ø  Hypertensive retinopathy grade II or higher

From Heart Foundation Guide to Management 2010 guide




The most up to date guidelines on blood pressure that I can find are the "National Vascular Disease Prevention Alliance Guidelines for the management of absolute cardiovascular disease risk". 2012.

In contrast to the 2008 (updated 2010) guidelines from the Heart Foundation "Guide to the Management of Hypertension", the former, more recent guidelines, recommend immediately treating anyone who is over age 45, at low or moderate risk (based on the Australian cardiovascular risk charts) with blood pressure ≥ 160/100.

Treatment should begin with any of the following
  • ACEi or ARB
  • CCB (dihydropyridine)
  • Low dose thiazide or thiazide like diuretic (in patients > age 65)*

* Note that thiazide diuretics have been associated with increased risk of new onset diabetes therefore use cautiously in patients with "pre-diabetes" or metabolic syndrome. The Heart foundation recommends reserving these agents as first-line for older patients in whom the benefits of managing isolated systolic hypertension and preventing stroke are likely to outweigh the risk of diabetes onset.

Always begin with the LOWEST recommended dose (e.g. ACEi or ARB).

If target not reached after 6 week trial
suggest ACEi (or ARB) + CCB (dihydropyridine)

If target not reached at 3 months
suggest ACEi (or ARB) + CCB + Thiazide

ACEi/ ARB are recommended in a number of settings for cardiac and renal benefit, they must be used cautiously/ avoided in patients with renal artery stenosis.

Beta Blockers are recommended post MI and in the setting of angina. Exercise caution in patients with depression, uncontrolled heart failure, bradycardia/ AV block and asthma/ COPD.
Combinations to avoid:

X ACEi (or ARB) + potassium sparing diuretic (spironolactone, amiloride)
= hyperkalaemia
X Beta blocker + verapamil 
= heart block
X ACEi + ARB
= hypotension and lack of efficacy

Common Adverse Effects
 ACEi (and ? ARB) can cause cough
CCBs may cause constipation (especially verapamil), flushing, headache and oedema
Thiazide diuretics can cause gout
Beta blockers can cause depression, lethargy, erectile dysfunction

If blood pressure is not responding to medication, reassess for;
  • non adherence
  • undiagnosed secondary cause
  • hypertensive effects of other drugs
  • treatment resistance due to sleep apnoea
  • hidden use of alcohol or recreational drugs
  • unrecognised high salt intake
  • white coat hypertension
  • technical factors affecting measurement
  • volume overload in CCF
Which of the following  combinations would you avoid?
  • Lisinopril 20mg daily and Olmesartan 30mg once daily
  • Eplerenone 50mg and Captopril 25mg
  • Atenolol 50mg daily and Verapamil CR 240mg once daily
  • Carvedilol 50mg and Amlodipine 10mg in a patient with CHD

Following blogs will cover management of hypertension in particular situations such as pregnancy, diabetes, stroke etc