A 51-year-old woman with a history of poor dentition secondary to methadone use is scheduled for dental extraction in one week. Her past medical history is significant for chronic heart failure. She is currently taking ramipril, bisoprolol, furosemide, and methadone. She has no known drug allergies.
What is the most appropriate antimicrobial prophylaxis to reduce her risk of infective endocarditis?
Ciprofloxacin
Doxycycline
Flucloxacillin
No antibiotic prophylaxis recommended
Rifampicin
Antibiotic prohylaxis to prevent infective endocarditis is not routinely recommended in the UK for dental and other procedures
Which procedures do not require antibiotic prophalaxis for IE?
NICE recommends the following procedures do not require prophylaxis:
- dental procedures
- upper and lower gastrointestinal tract procedures
- genitourinary tract; this includes urological, gynaecological and obstetric procedures and childbirth
- upper and lower respiratory tract; this includes ear, nose and throat procedures and bronchoscopy
It is important to note that these recommendations are not in keeping with the American Heart Association/European Society of Cardiology guidelines which still advocate antibiotic prophylaxis for high-risk patients who are undergoing dental procedures.
When do guidelines suggest to give abx prophalaxis for infective endocarditis?
The guidelines do however suggest:
- any episodes of infection in people at risk of infective endocarditis should be investigated and treated promptly to reduce the risk of endocarditis developing
- if a person at risk of infective endocarditis is receiving antimicrobial therapy because they are undergoing a gastrointestinal or genitourinary procedure at a site where there is a suspected infection they should be given an antibiotic that covers organisms that cause infective endocarditis
ESC guidelines for IE prophalaxis
ESC Guideline: Antibiotic prophylaxis is recommended in patients at high risk of IE undergoing an oral-dental procedure.
Populations at high risk of infective endocarditis (IE) include patients with previous IE; patients with a surgically implanted valve, transcatheter valve, or prior valve repair; patients with uncorrected cyanotic congenital heart disease (CHD) or those with CHD and prior repair involving prosthetic material; and patients with a ventricular assist device.
A 55-year-old man who has a history of ischaemic heart disease presents with myalgia. His long-term medications include aspirin, simvastatin and atenolol. Given his statin use a creatine kinase is measured and reported as follows:
Creatine kinase 1,420 u/l (< 190 u/l)
His problems seem to have followed the prescription of a new medication. Which one of the following is most likely to have caused the elevation in creatine kinase?
Rifampicin
Felodipine
Clarithromycin
Isosorbide mononitrate
Amitriptyline
Clarithromycin
Which commonly used antibiotic medication interacts with statins and why?
- Clarithromycin and erythromycin and why
- The interaction between clarithromycin and simvastatin can increase the risk of myopathy or rhabdomyolysis, a severe muscle condition that can lead to kidney damage. Both conditions are associated with elevated creatine kinase levels.
- Clarithromycin inhibits CYP3A4, an enzyme involved in the metabolism of many drugs including simvastatin.
- When CYP3A4 is inhibited by clarithromycin, it can lead to increased levels of simvastatin in the body, thereby increasing the risk of statin-related side effects such as myalgia and elevated creatine kinase levels.
How do statins work?
Statins inhibit the action of HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis.
Adverse effects of statins
- myopathy: includes myalgia, myositis, rhabdomyolysis and asymptomatic raised creatine kinase.
- liver impairment
- there is some evidence that statins may increase the risk of intracerebral haemorrhage in patients who’ve previously had a stroke. This effect is not seen in primary prevention. For this reason the Royal College of Physicians recommend avoiding statins in patients with a history of intracerebral haemorrhage
Which patients are at higher risk of myopathy with statins?
Risks factors for myopathy include advanced age, female sex, low body mass index and presence of multisystem disease such as diabetes mellitus.
Which statins are more likely to have myopathy as a side effect?
Myopathy is more common in lipophilic statins (simvastatin, atorvastatin) than relatively hydrophilic statins (rosuvastatin, pravastatin, fluvastatin)
Monitoring with statins
the 2014 NICE guidelines recommend checking LFTs at baseline, 3 months and 12 months. Treatment should be discontinued if serum transaminase concentrations rise to and persist at 3 times the upper limit of the reference range
Contraindication to statins
- macrolides (e.g. erythromycin, clarithromycin) are an important interaction. Statins should be stopped until patients complete the course
- pregnancy
Who should receive a statin?
- all people with established cardiovascular disease (stroke, TIA, ischaemic heart disease, peripheral arterial disease)
- anyone with a 10-year cardiovascular risk >= 10%
- patients with type 2 diabetes mellitus should now be assessed using QRISK2 like other patients are, to determine whether they should be started on statins
- patients with type 1 diabetes mellitus who were diagnosed more than 10 years ago OR are aged over 40 OR have established nephropathy
When should statins be taken and why?
- Statins should be taken at night as this is when the majority of cholesterol synthesis takes place.
- This is especially true for simvastatin which has a shorter half-life than other statins
Which statin to use and dose
- atorvastatin 20mg for primary prevention. increase the dose if non-HDL has not reduced for >= 40%
- atorvastatin 80mg for secondary prevention
A 54-year-old female presents with an acutely painful hand. She has a history of hypertension, Raynaud’s phenomenon, and has smoked twenty cigarettes a day since she was twenty-two years old. She describes the pain as ‘different from her usual Raynaud’s,’ there has been no relief of symptoms despite wearing gloves and making sure her hands are warm. On examination she has a blood pressure of 158/80 mmHg, her right hand is blanched white and feels cold. The colour of her forearm is normal. The radial pulse is not palpable at the wrist.
Which of the following conditions is the most likely explanation for her symptoms?
Buerger’s disease
Osteoarthritis of the wrist
Radial artery dissection
Raynaud’s phenomenon
Superficial vein thrombosis
Buerger’s disease
In Raynaud’s phenomenon with extremity ischaemia think Buerger’s disease
What is buerger’s disease?
Buerger’s disease (also known as thromboangiitis obliterans) is a small and medium vessel vasculitis that is strongly associated with smoking.
What is buerger’s disease characterized by?
- characterised by progressive inflammation and thrombosis of the small and medium arteries in the hands and feet.
- It can present as acute ischaemia or chronic progressive ischaemic changes to the skin/tissues. May also be seen as intermittent claudication and ischemic ulcers
- Superficial thrombophlebitis may occur
- Patient may also have a history of Raynaud’s
- Ultimately it may result in gangrene of the affected area, often needing amputation. It is strongly associated with an extensive smoking history
