November 29, 2010

USMLE 2 Question 25

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A 48 year old female teacher has an x-ray taken because of a recurrent dry cough. It is noted incidentally that there is sclerosis, destruction and fragmentation. On examination it is noted that she has decreased pain sensation over her shoulder joint and upper limb area.

These features are suggestive of:

a) juvenile rheumatoid arthritis
b) syringomyelia
c) epidermolysis bullosa
d) bronchial carcinoma
e) infectious mononucleosis

The correct answer is B

In syringomyelia, decreased pain sensation and impaired position sense contribute to the massive destruction of the the shoulder.

USMLE 2 Question 24

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A patient with long standing renal insufficiency develops mild generalised ecchymoses. Platelet dysfunction is suspected despite a normal platelet count.

Which test would be most useful in this patient?

a) bone marrow aspirate
b) Clot retraction
c) Tourniquet test
d) Bleeding time
e) Prothrombin time (PT)

The correct answer is D

Renal insufficiency is associated with a bleeding tendency. Hemorrhagic manifestations are usually mild (i.e., ecchymoses or purpura) but can be severe in occasional patients who may have gastrointestinal tract or intracranial bleeding.

Modern techniques for the management of uremia have definitely reduced the incidence of severe bleeding episodes in patients with renal failure, but hemorrhages still represent a major clinical problem, particularly for patients undergoing surgery or invasive procedures.

The bleeding time is frequently abnormal in acquired platelet function abnormality such as that seen in uremia and the myeloproliferative syndromes. The bleeding time is usually abnormal in congenital defects of platelet function such as Glanzmann's thrombasthenia. The bleeding time is most helpful as an indicator of platelet abnormality, either in number or function. The bleeding time is usually normal when the platelet count is decreased but still more than 100,000/mm3 (100 × 109 /L). With platelet counts less than 100,000/mm3, there is a rough correlation between severity of thrombocytopenia and degree of bleeding time prolongation.

The bleeding time is usually abnormal in congenital defects of platelet function such as Glanzmann's thrombasthenia. The bleeding time is frequently abnormal in acquired platelet function abnormality such as that seen in uremia and the myeloproliferative syndromes.

In uremia, there frequently are demonstrable abnormalities in platelet function tests but not sufficient to entirely explain bleeding problems. In addition, up to 50% of uremic patients develop some degree of thrombocytopenia.

USMLE 2 Question 23

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A patient has symptomatic WPW syndrome but is refusing surgery.

The medication of choice is:

a) Subclass IB drugs alone plus an AV nodal blocker
b) Subclass IV drugs plus an AV nodal blocker
c) subclass II drugs
d) an AV nodal blocker alone
e) a membrane-active antiarrhythmic drug (class IC or III) plus an AV nodal blocker

The correct answer is E

The 3 main treatment modalities for WPW syndrome are drug therapy, electrical (ie, RF) ablation, and surgical ablation.

Ablation is the first-line treatment for symptomatic WPW syndrome. It has replaced surgical treatment and most drug treatment. However, drug therapy can be useful in some instances, such as in patients who refuse ablation or in patients in whom ablation fails in one or two attempts.

For patients treated longitudinally with pharmacotherapy, consideration should be given to a membrane-active antiarrhythmic drug (class IC or III) with an AV nodal blocker, rather than just an AV nodal blocker, because of the potential for extremely rapid rates during preexcited atrial fibrillation or flutter.

USMLE 2 Question 22

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A 35 year old has severe hemoptysis three weeks following a respiratory tract infection. Investigations reveal pulmonary infiltrates suggestive of alveolar hemorrhage. She is found to have hypertension, generalised edema. Urinalysis reveals hematuria and red cell casts. Her renal function is reduced. Serologic tests for ANA and rheumatoid factor are negative. Circulating antibodies to the glomerular basement memebrane are discovered.

A likely diagnosis is:

a) polycystic disease of the kidneys
b) Berger's nephritis
c) systemic lupus erythematosus
d) renal vein thrombosis
e) Goodpasture's syndrome

The correct answer is E

The diagnosis of anti-GBM antibody disease depends on the demonstration of circulating anti-GBM antibodies and/or the finding of linear deposits of immunoglobulin along glomerular or alveolar basement membranes. In the appropriate clinical setting (alveolar hemorrhage and urinary findings suggestive of active glomerulonephritis), a positive test for circulating anti-GBM antibodies establishes the diagnosis and obviates the need for further diagnostic testing.

True Goodpasture syndrome should consist of the following triad: 1) proliferative, usually crescentic, glomerulonephritis; 2) pulmonary hemorrhage; and 3) the presence of anti-GBM antibodies. When present, the renal disease may be severe and follow a fulminant course, progressing to renal failure over hours to weeks if untreated.

Approximately 20% of patients presenting with rapidly progressive glomerulonephritis will have anti-GBM antibody disease with or without lung hemorrhage. In anti-GBM antibody disease, the pulmonary hemorrhage may precede, occur concurrently with, or follow the glomerular involvement. Documentation of anti-GBM antibody-induced disease may be accomplished by renal biopsy, or by establishing the presence of circulating anti-GBM antibodies. Radioimmunoassay, ELISA, and immunoblotting for the antibodies are both highly specific and sensitive.

Glomerulonephritis The majority of cases of anti-GBM antibody disease occur in the second through the fifth decade of life, although cases have been diagnosed late in life. An upper respiratory tract infection precedes the onset of disease in 20% to 60% of cases. The most common extrarenal findings are by far related to pulmonary involvement. Patients may have cough, dyspnea, and shortness of breath, and hemoptysis may vary from trivial amounts to life-threatening massive amounts associated with exsanguination and suffocation.

In almost three fourths of cases, pulmonary hemorrhage precedes or is coincident with the glomerular disease. Hemoptysis will occur in virtually all patients with pulmonary and renal disease at some point during the course of their illness and will be the presenting symptom in a majority of individuals. Symptoms referable to the renal disease usually are nonspecific and are related to hematuria or to the degree of azotemia.

The clinical renal presentation may be with an acute nephritic picture with hypertension, edema, hematuria and active urinary sediment, and reduced renal function. Laboratory evaluation in patients with Goodpasture syndrome typically shows active urinary sediment with red blood cells and red cell casts on urinalysis. Proteinuria, although commonly present, is usually not in the nephrotic range, perhaps secondary to the reduction in GFR commonly present. Serologic tests such as ASLO, ANA, serum complement levels, rheumatoid factor, cryoglobulins, and CICs are all either negative or normal. Circulating anti-GBM antibodies are present in over 90% of patients.

In patients with pulmonary involvement, the chest x-ray results are abnormal in over 75% and typically show infiltrates corresponding to areas of pulmonary hemorrhage. Approximately 60% to 80% of patients with anti-GBM antibody disease will have clinically apparent pulmonary and renal disease, whereas some 20% to 40% will have glomerulonephritis alone, and 10% or less will have isolated pulmonary disease.

USMLE 2 Question 21

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An enzyme found in tears and saliva is known to damage bacterial cell walls.

It does this by:

a) dissolving the cytoplasmic membrane
b) breaking the covalent links between teichoic acid and muramic acid
c) hydrolyzing the link between N-acetyl glucosamine and N-acetyl muramic acid
d) inhibiting cell wall protein synthesis
e) converting D-alanine to L-alanine

The correct answer is C

The correct answer is c) hydrolyzing the link between N-acetyl glucosamine and N-acetyl muramic acid.

Lysozyme is a small 14 kDa protein found in tears. It contains 4 disulfide bonds and its secondary structure is both helical and sheet.

It hydrolyzes the bond between NAG subunits in bacterial cell walls and therefore serves as a defence mechanism.

November 28, 2010

Pass the Part 1 of the MRCP, WACP, NPMCN, PLAB and USMLE exams

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Postgraduate medical exams like the Royal College of Physicians' MRCP exam, the West African College of Physicians WACP exams, and the National Postgraduate Medical College (of Nigeria) NPMC exams can be quite hard and daunting to get through but the better prepared the candidate is, the greater the chance of success early on either at the first or second attempt.

November 27, 2010

Preexposure Chemoprophylaxis Reduces HIV Infections in Gay and Bisexual Men

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From Medscape Medical News

November 23, 2010 — A combination of oral antiretroviral therapy for preexposure chemoprophylaxis (PrEP) against HIV demonstrates moderate effectiveness in a major, multicontinent clinical trial that heralds a new — and expensive — means of curbing the spread of AIDS.
The study, called iPrEx (for the Spanish name for the study, which translates to Prexposure Prophylaxis Initiative), involved 2499 men and transgender women (1% of the group) who have sex with men. All tested HIV seronegative at baseline but reported engaging in sexual practices that put them at high risk for infection.

Half of the subjects received a placebo and the other half received a combination pill of 2 antiretroviral drugs — emtricitabine, 200 mg, and tenofovir disoproxil fumarate, 300 mg (Truvada; Gilead Sciences), which is currently approved by the US Food and Drug Administration for treatment of HIV infection. Both cohorts in the study, who were followed up for a median of 1.2 years, also received HIV education, testing, and condoms.

As a result of the iPrEx study findings, experts are expecting an increase in off-label prescription of emtricitabine-tenofovir for HIV-negative men who want extra protection. In addition, experts are advising such individuals that they should still use condoms and take other precautions in addition to antiretrovirals.

"PrEP is best conceived as a back-up," said Robert Grant, MD, lead study author of an article published online today in the New England Journal of Medicine that reports the study findings.

The HIV infection rate of 2.88% in the treatment group was 44% lower than the infection rate of 5.13% in the placebo group. Although the additional level of protection offered by emtricitabine-tenofovir was less than the study authors hoped for, they said the risk for infection decreased by more than 70% for individuals who took their pills on 90% or more of the days in the study. Temporary adverse effects, such as nausea, and the knowledge that they were given either a placebo or an unproven medication may have explained why some participants did not take their medicine faithfully, or at all.

Mitchell Warren, executive director of AVAC, an international organization that promotes HIV prevention, called the 44% reduction in HIV risk "modest" and needing improvement but nevertheless "thrilling."

"This is a game-changing trial result," Mr. Warren told Medscape Medical News. "What comes next is how we motivate people for pill-taking behavior."

Paul Sax, MD, an associate professor at Harvard Medical School and clinical director of the HIV Program in the Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, called iPrEx "a landmark study."

"We've been waiting some time to find out whether PrEP using oral medications would work," said Dr. Sax. "It seems to, although the efficacy turned out to be a bit lower than some had predicted."

The $43.6 million study was conducted in 11 sites in 6 countries — the United States, South Africa, Thailand, Peru, Ecuador, and Brazil. The National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health paid for roughly two-thirds of the cost, with the rest funded by The Bill & Melinda Gates Foundation. Gilead Sciences donated the emtricitabine-tenofovir and placebo agents.

Adherence Could Improve in Open-Label Study

The iPrEx is the second major study this year demonstrating the efficacy of PrEP. In July, South African researchers in the so-called CAPRISA 004 trial published an article in Science Express reporting how a vaginal gel containing tenofovir lowered the risk of HIV infection in sexually active women by 39%.

The iPrEx study has quickly garnered superlatives, but more research lies ahead before the "chemical condom" becomes accepted clinical practice.

"This is just one study," NIAID Director Anthony Fauci, MD, said at a press conference yesterday. The study results apply only to men who have sex with other men, Dr. Fauci explained, and the results cannot be extrapolated to other groups. Upcoming PrEP studies will look at the value of the treatment for women and heterosexual men.

In addition, Dr. Grant's research team will conduct a follow-up study in which all iPrEx subjects, including those in the placebo group, can receive emtricitabine-tenofovir for 18 months on an open-label basis. This study, scheduled to start in early 2011, will provide more information about the 'therapy's long-term effectiveness as well as the pill-taking behavior of participants and how to improve adherence. The hope is that adherence will increase because patients will know that they are taking a proven medication, which was not the case in the original iPrEx study published today.

Dr. Grant, a senior investigator at the J. David Gladstone Institutes at the University of California–San Francisco, told Medscape Medical News that getting gay men to take a daily pill to ward off HIV is a feasible goal.

"People use cholesterol-lowering medicine every day," said Dr. Grant. "Women use oral contraceptives every day."

One bonus of PrEP, Dr. Grant and coauthors write in their New England Journal of Medicine article, is that daily pill taking can remind patients to be more diligent about other safe-sex practices. During the iPrEx trial, for example, the percentage of participants in both the placebo and treatment groups who had sex without using a condom decreased from 60% at baseline to roughly 30%. Likewise, the number of their sexual partners decreased. These findings run counter to the fear that patients may drop other safe-sex practices because of a belief that all they need is PrEP.

CDC Issues Precautions for Off-Label PrEP

Experts expect the iPrEx study results will increase off-label use of emtricitabine-tenofovir as a preexposure prophylactic.

"There will be more people walking into the doctor's office and saying, 'Will you write me a prescription?' " Dr. Fauci said at yesterday's press conference.

By all accounts, a smattering of clinicians already prescribe emtricitabine-tenofovir as a form of PrEP. Full report here

November 19, 2010

Understanding Medical Exams: PLAB 1 and 2

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The Professional and Linguistic Assessments Board (PLAB) Test is designed to assess your knowledge and skills, and your ability to work safely in your first appointment as a senior house officer in a British hospital. It is the main route by which International Medical Graduates (IMGs) demonstrate that they have the necessary skills and knowledge to practise medicine in the UK.

November 17, 2010

Required Minimum IELTS scores for PLAB changed

The minimum IELTS scores we accept as evidence of English proficiency are changing on 1 October 2010. This page sets out the arrangements for the change.

USMLE 1 Question 25

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A 70 year old known hypertensive man presents to the general practitioner complaining of sudden onset of a drooping right eyelid and slurred speech. Examination revealed the tongue deviated to the right.

A Horner's syndrome on the right was diagnosed. Further examination showed a loss of pain sensation of the left side. The physician also noted a poor visual acuity from both eyes.

Which area of the brain is involved in ischaemia?

a) spinal cord at the level of C2
b) dorsolateral medulla
c) anterior pons
d) right side of midbrain
e) left side of midbrain

The correct answer is A


This patient's clinical condition suggests ischemia of the dorsolateral medulla. Involvement of the ninth and tenth cranial nerve nuclei result in ipsilateral tongue deviation to the right and ipsilateral palatal weakness, respectively.

Involvement of the central sympathetic pathway results in an ipsilateral Horner's syndrome. Damage to the lateral spinothalamic tract results in contralateral loss of pain and temperature sensation.

The poor visual acuity in this case was irrelevant and an incidental finding- this was corrected with reading glasses.

USMLE 1 Question 24

No comments:
An elderly male patient with right hip pain is suspected of having osteoarthritis. This would be confirmed by the presence of:

a) subperiosteal thickening
b) pericardial rub
c) tight skin
d) papular rash
e) subchondral bony sclerosis

The correct answer is E

Radiographic appearances in osteoarthritis are usually normal early on. Later, however, there is typically a narrowed joint space, osteophyte formation, subchondral bony sclerosis, and cyst formation.

USMLE 1 Question 23

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A young man with anorexia, nausea, and brown urine is thought to have acute viral hepatitis following hepatitis B infection.Screening serologic studies show that IgM anti-HBV core AB is positive.

Which of the following mechanisms is likely to explain the hepatic injury in this patient?

a) Direct injury by viral surface antigen
b) hepatocyte lysis by IgM antibody to viral core antigen
c) obstruction of the microcirculation of the liver by B lymphocytes
d) disruption of the hepatocyte membrane by the hepatitis B virus
e) T lymphocyte-mediated lysis of infected hepatic cells

The correct answer is E


The symptoms (anorexia, nausea, and brown urine) are typical of hepatitis.

The body fights viral infections by CD8+ T cell-mediated lysis of infected cells that present viral antigens on their surface. The viral surface antigen does not directly injure hepatocyte membranes . The role of the host immune response in determining clinical outcome following hepatitis B virus (HBV) infection is well recognized.

In patients infected with hepatitis B, therapies, diseases, or conditions that impair specific lymphocyte responses lead to a high rate of chronic infection; in addition, the vigor of the host T-cell response to HBV-encoded antigenic peptides appears to correlate directly with the degree of acute hepatocellular injury and inversely with levels of HBV viremia. IgM directed against core antigen does not cause the hepatocytes to lyse.

USMLE 1 Question 22

No comments:
Which of the following is true of the optic disc?

a) no arteries pass through it
b) no veins pass through it
c) it appears dark red on fundoscopy
d) contains a concentration of photoreceptors
e) it is normally less than 1cm in diameter

The correct answer is E


This is the point at which axons leave the eyeball and join the optic nerve. Also, arteries enter and veins leave the retina at the optic disk. There are no photoreceptors here, hence it is known as the 'blind spot'. It is a pinky-yellow oval, approximately 2mm in diameter, and situated in the nasal retina

USMLE 1 Question 21

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Three types of RNA involved in comprising the structural and functional core for protein synthesis, serving as a template for translation, and transporting amino acid, respectively, are:

a) mRNA, tRNA, rRNA
b) rRNA, tRNA, mRNA
c) tRNA, mRNA, rRNA
d) tRNA, rRNA, mRNA
e) rRNA, mRNA ,tRNA

The correct answer is E


rRNA's serve a structural and functional role in protein synthesis as a component of the ribosome. The transpeptidization reaction has been shown to be caused by rRNA.

mRNA is transcribed from DNA to be used as a template for protein synthesis. The tRNA's bring the correct amino acid into the protein synthesis process.

November 09, 2010

MRCP 1 Question 25

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A 35 year old male has a chronic anal fissure.

This is typically managed by:

a) abdominal perineal resection
b) chemotherapy and radiatiotherapy
c) CT guided drainage
d) transverse colectomy
e) internal sphincterotomy

The correct answer is E

Chronic fissures are managed by subcutaneous or open lateral internal sphincterotomy, posterior internal sphincterotomy with advancement flap, or manual dilatation.

MRCP 1 Question 24

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What is most likely diagnosis of this ECG?

[click on image to enlarge]

What is the most likely diagnosis:

a) pulmonary embolism
b) early repolarization
c) acute pericarditis
d) acute myocardial infarction
e) Myocarditis

The correct answer is C

The electrocardiogram (ECG) is a useful, simple tool that may aid in the diagnosis of acute pericarditis. Typical ECG findings include diffuse concave-upward ST-segment elevation and, occasionally, PR-segment depression.

ECG changes of both acute myocardial infarction and early repolarization can appear similar to ECG changes of acute pericarditis. However, these conditions can usually be excluded by an accurate history, physical examination and recognition of a few key features on the ECG.

In this ECG of a patient with acute pericarditis, note diffuse concave-upward ST-segment elevation, ST-segment depression in aVR, and PR-segment depression which is best demonstrated in leads II and V3. Note lack of reciprocal ST-segment changes, an important feature differentiating acute pericarditis from acute myocardial infarction.

Also note that the ST/T ratio is greater than 0.25, a finding frequently indicative of acute pericarditis.

MRCP 1 Question 23

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Vascular abnormalities are a known side effect of several cytotoxic drugs.

Which of the following cytotoxic drugs is most likely to lead to thrombosis and thromboembolism?

a) methotrexate
b) 5-fluorouracil
c) taxoids
d) cyclopentenyl cytosine
e) trastuzumab

The correct answer is A

Please refer to the table below:

MRCP 1 Question 22

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Mick, a 58 years old man is admitted to the hospital with ocular pain and diminished vision. On examination he is found to have shallow breathing, wheezing and profuse rhinorrhea. He admits that these symptoms started when he was in his greenhouse spraying flowers with an insecticide. He has broght the insecticide with him. It is discovered that this insecticide contains carbaryl ( a reversible cholinesterase inhibitor).

Treatment should include:

a) Pralidoxime
b) Terbutaline
c) Epinephrine
d) Betamethasone
e) Atropine

The correct answer is E

What we have here are signs of cholinergic activation at its maximum level. In other words, toxicity with a cholinergic drug. The list includes rhinorrhea, lacrimation, wheezing, shallow breathing, and ocular pain and diminished vision.

When parasympathetic activation accurs there are increased secretions in the whole body. This causes an increased intraocular pressure, which causes ocular pain. Meiosis causes blurred vision. Bronchoconstriction causes wheezing.

Mick was working with an insecticide.

Terbutaline and epinephrine are not appropriate treatments. Both are sympathetic drugs. Betamethasone is a Glucacorticoids. It would not solve our problem. Pralidoxime reverses the inhibition of organophosphates.

Organophosphates are irreversible inhibitors of cholinesterase. It would be ineffective in our case because a reversible inhibitor is the cause of the poisoning. Therefore, the best thing to do is to reverse the symptoms that Mick has with atropine.

Atropine is a cholinergic blocker. Therefore, the correct answer is E

MRCP 1 Question 21

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A fifty-five year old with chronic cardiac failure is on treatment with digoxin and the a loop diuretic.

This combination is likely to cause digoxin toxicity by the following reason:

a) this combination increases the half-life of digoxin
b) diuretics decrease potassium levels
c) frusemide and digoxin interact to form a poisonous compound
d) digoxin is a competitive inhibitor of frusemide
e) the above statement is wrong, loop diuretics are not a recognised cause of increased digoxin toxicity

The correct answer is B

Loop and thiazide diuretics decrease potassium and magnesium levels, predisposing patients taking both a diuretic and digoxin to an increased risk of digoxin toxicity.

Also, amphotericin B (Fungizone), an antifungal, has an additive potassium-lowering effect when given with a thiazide or loop diuretic. Thiazides may increase the blood levels of lithium.

Bile acid sequestrants cholestyramine (Questran) and colestipol (Colestid) decrease the absorption of thiazide diuretics when given concomitantly, while nonsteroidal anti-inflammatory drugs such as indomethacin (Indocin) may decrease the therapeutic effects of both the loop and thiazide diuretics

November 04, 2010

US Partners PEPFAR to Transform African Medical Education With $130million Investment

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The U.S. Department of Health and Human Services is partnering with the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR) to invest as much as $130 million over five years to transform African medical education and dramatically increase the number of health care workers.

November 03, 2010

Latest NICE Guidelines on Chronic Heart Failure, Transient Loss of Consciousness and Dronedarone

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The National Institute for Health and Clinical Excellence (NICE) is an independent organisation responsible for providing national guidance on promoting good health and preventing and treating ill health.

Latest NICE Guideline on Chronic Heart Failure

From British Journal of Cardiology
Posted: 10/27/2010; Br J Cardiol. 2010;17(5):209 © 2010 Sherborne Gibbs Ltd.

NICE has published new guidance on the management of chronic heart failure. This updates and replaces the previous guideline in this area (NICE clinical guideline 5).

The new guideline, which covers the management of heart failure in adults in primary and secondary care, contains new and updated recommendations on diagnosis, pharmacological treatment, monitoring and rehabilitation.

Key priorities for implementation in the guidance include:
  • Referring patients with suspected heart failure and previous myocardial infarction (MI) to transthoracic Doppler 2D echocardiography and specialist assessment within two weeks;
  • Measuring serum natriuretic peptides in patients with suspected heart failure without previous MI; referring those with very high levels of serum natriuretic peptides to urgent transthoracic Doppler 2D echocardiography and specialist assessment within two weeks;
  • First-line treatments for heart failure due to left ventricular systolic dysfunction are angiotensin converting enzyme (ACE) inhibitors and beta blockers licensed for heart failure. The latter should be offered to older patients and other special groups;
  • If symptoms persist despite optimal first-line treatment, specialist advice should be sought and a second-line treatment should be added such as an aldosterone antagonist, an angiotensin receptor blocker (also an alternative first-line treatment) or hydralazine in combination with nitrate;
  • Monitoring all patients to include a clinical review;
  • Patients with heart failure should be offered a supervised group exercise-based rehabilitation programme if they are stable;
  • Patients from hospital should be discharged only when their condition is stable and their management plan optimised, taking into account patient/carer wishes and the level of support and care in the community.
Full guidance can be found at

Latest NICE Guideline on Transient Loss of Consciousness

On the transient loss of consciousness in adults and young people, NICE highlights how people who experience spontaneous blackouts may not be receiving accurate or timely diagnoses because of inadequate assessments made by health care staff.

The full guidance is available at

NICE recommendation on Dronedarone

NICE also published its final technology appraisal on the use of dronedarone (Multaq®) for the treatment of atrial fibrillation (AF). It recommends it as a possible treatment for some people with non-permanent AF, such as those who have tried another drug which has not worked or for those who are at higher risk, such as patients with diabetes, those over 70 years old, those taking at least two drugs for high blood pressure and those with a history of stroke or a blood clot.

The full guidance is available at

Article published with materials from Medscape © 1994-2010 by WebMD LLC