ACC/AHA/ESC 2006 Guidelines for Management of Atrial Fibrillation – ‘Rate Control’

In addition to allowing adequate time for ventricular filling and avoiding rate-related ischemia, enhancement of intraventricular conduction with rate reduction may result in improved hemodynamics in atrial fibrillation. It may be useful to evaluate the heart rate response to submaximal or maximal exercise or to monitor the rate over an extended period (e.g., by 24-h Holter recording).

Criteria for rate control vary with patient age but usually involve achieving ventricular rates between 60 and 80 beats per minute at rest and between 90 and 115 beats per minute during moderate exercise.

Hemodynamic and Clinical Consequences of Rapid rate:
Patients who are symptomatic with rapid ventricular rates during AF require prompt medical management, and cardioversion should be considered if symptomatic hypotension, angina, or HF is present. A sustained, uncontrolled tachycardia may lead to deterioration of ventricular function (tachycardia-related cardiomyopathy) and that improves with adequate rate control.

Tachycardia-induced cardiomyopathy tends to resolve within 6 months of rate or rhythm control; when tachycardia recurs, LV ejection fraction declines and HF develops over a shorter period, and this is associated with a relatively poor prognosis.

Pharmacological Rate Control During Atrial Fibrillation
RECOMMENDATIONS:

Class I :

1. Measurement of the heart rate at rest and control of the rate using pharmacological agents (either a beta blocker or nondihydropyridine calcium channel antagonist, in most cases) are recommended for patients with persistent or permanent AF.
   (Level of Evidence: B)
2. In the absence of preexcitation, intravenous dministration
   of beta blockers (esmolol, metoprolol, or propranolol) or nondihydropyridine calcium channel antagonists (verapamil, diltiazem) is recommended to slow the ventricular response to AF in the acute setting, exercising caution in patients with hypotension or HF. (Level of Evidence: B)
3. Intravenous administration of digoxin or amiodarone is recommended to control the heart rate in patients with AF and HF who do not have an accessory pathway. (Level of Evidence: B)
4. In patients who experience symptoms related to AF during activity, the adequacy of heart rate control should be assessed during exercise, adjusting pharmacological treatment as necessary to keep the rate in the physiological range. (Level of Evidence: C)
5. Digoxin is effective following oral administration to control the heart rate at rest in patients with AF and is indicated for patients with HF, LV dysfunction, or for sedentary individuals. (Level of Evidence: C)

Class IIa:

1. A combination of digoxin and either a beta blocker or nondihydropyridine calcium channel antagonist is reasonable to control the heart rate both at rest and during exercise in patients with AF. The choice of medication should be individualized and the dose modulated to avoid bradycardia. (Level of Evidence:B)
2. It is reasonable to use ablation of the AV node or accessory pathway to control heart rate when pharmacological therapy is insufficient or associated with side effects. (Level of Evidence: B)
3. Intravenous amiodarone can be useful to control the heart rate in patients with AF when other measures are unsuccessful or contraindicated. (Level of Evidence: C)
4. When electrical cardioversion is not necessary in patients with AF and an accessory pathway, intravenous procainamide or ibutilide is a reasonable alternative. (Level of Evidence: C)

Class IIb:

1. When the ventricular rate cannot be adequately controlled both at rest and during exercise in patients with AF using a beta blocker, nondihydropyridine calcium channel antagonist, or digoxin, alone or in combination, oral amiodarone may be administered to control the heart rate. (Level of Evidence: C)
2. Intravenous procainamide, disopyramide, ibutilide, or amiodarone may be considered for hemodynamically stable patients with AF involving conduction over an accessory pathway. (Level of Evidence: B)
3. When the rate cannot be controlled with pharmacological
   agents or tachycardia-mediated cardiomyopathy is suspected, catheter-directed ablation of the AV node may be considered in patients with AF to control the heart rate. (Level of Evidence: C)

Class III:

1. Digitalis should not be used as the sole agent to control the rate of ventricular response in patients with paroxysmal AF. (Level of Evidence: B)
2. Catheter ablation of the AV node should not be attempted without a prior trial of medication to control the ventricular rate in patients with AF. (Level of Evidence: C)
3. In patients with decompensated HF and AF, intravenous administration of a nondihydropyridine calcium channel antagonist may exacerbate hemodynamic compromise and is not recommended. (Level of Evidence: C)
4. Intravenous administration of digitalis glycosides or nondihydropyridine calcium channel antagonists to patients with AF and a preexcitation syndrome may paradoxically accelerate the ventricular response and is not recommended. (Level of Evidence: C)

When rapid control of the ventricular response to AF is required or oral administration of medication is not feasible, medication may be administered intravenously. Otherwise, in hemodynamically stable patients with a rapid ventricular response to AF, negative chronotropic medication may be administered orally. Combinations may be necessary to achieve rate control in both acute and chronic situations, but proper therapy requires careful dose titration. Some patients develop symptomatic bradycardia that requires permanent pacing. Nonpharmacological therapy should be considered when pharmacological measures fail.

Specail considerations in patients with the Wolff-Parkinson-White (WPW) Syndrome: Intravenous beta blockers, digitalis, adenosine, lidocaine, and nondihydropyridine calcium channel antagonists, all of which slow conduction across the AV node, are contraindicated in patients with the WPW syndrome and tachycardia associated with ventricular preexcitation, because they can facilitate antegrade conduction along the accessory pathway during AF, resulting in acceleration of the ventricular rate, hypotension, or ventricular fibrillation. When the arrhythmia is associated with hemodynamic compromise, however, early direct-current cardioversion is indicated. In hemodynamically stable patients with preexcitation, type I antiarrhythmic agents or amiodarone may be administered intravenously. Beta blockers and calcium channel blockers are reasonable for oral chronic use.

Patients With Both Atrial Fibrillation and Atrial Flutter:
A patient treated with AV nodal blocking drugs whose ventricular rate is well controlled during AF may experience a rise or fall in rate if he or she develops atrial flutter. This is also true when antiarrhythmic agents such as propafenone or flecainide are used to prevent recurrent AF. These compounds may increase the likelihood of 1:1 AV conduction during atrial
flutter, leading to a very rapid ventricular response. Thus, when
these agents are given for prophylaxis against recurrent paroxysmal AF or atrial flutter, AV nodal blocking drugs should be routinely coadministered. An exception may be patients with
paroxysmal AF who have undergone catheter ablation of the
cavotricuspid isthmus to prevent atrial flutter.

Regulation of Atrioventricular Nodal Conduction by Pacing:
Because ventricular pacing prolongs the AV nodal refractory period as a result of concealed retrograde penetration, it eliminates longer ventricular cycles and may reduce the number of short ventricular cycles related to rapid AV conduction during AF. Pacing at approximately the mean ventricular rate during spontaneous AV conduction can regulate
the ventricular rhythm during AF. This may be useful for patients with marked variability in ventricular rates or for those who develop resting bradycardia during treatment with medication.

AV Nodal Ablation:
AV nodal ablation in conjunction with permanent pacemaker
implantation provides highly effective control of the heart rate
and improves symptoms in selected patients with AF. In general, patients most likely to benefit from this strategy
are those with symptoms or tachycardia-mediated cardiomyopathy related to rapid ventricular rate during AF that cannot be controlled adequately with antiarrhythmic or negative chronotropic medications.

Catheter ablation of inferior atrial inputs to the AV node slows the ventricular rate during AF and improves symptoms without
pacemaker implantation. This technique has several limitations, however, including inadvertent complete AV block
and a tendency of ventricular rate to rise over the 6 months following ablation. Ablation of the AV inputs in the atrium may improve the reliability of the junctional escape mechanism. 

Complications of AV nodal ablation include those associated with pacemaker implantation, ventricular arrhythmias, thromboembolism associated with interruption of anticoagulation, the rare occurrence of LV dysfunction, and progression from paroxysmal to persistent AF. Limitations include the persistent need for anticoagulation, loss of AV synchrony, and lifelong pacemaker dependency. There is also a finite risk of sudden death due to torsades de pointes or  ventricular fibrillation. Patients with abnormalities of diastolic ventricular compliance who depend on AV synchrony to maintain cardiac output, such as those with hypertrophic cardiomyopathy or hypertensive heart disease, may experience persistent symptoms after AV nodal ablation and pacemaker implantation. Hence, patients should be counseled regarding each of these considerations before proceeding with this irreversible measure.

Patients with normal LV function or reversible LV dysfunction
undergoing AV nodal ablation are most likely to benefit from standard AV nodal ablation and pacemaker implantation. For those with impaired LV function not due to tachycardia, a biventricular pacemaker with or without defibrillator capability should be considered. Upgrading to a biventricular device should be considered for patients with heart failure and an RV pacing system who have undergone AV node ablation.

Ref: J. Am. Coll. Cardiol. 2006;48;e149-e246

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Are you preparing for FNB Entrance????

Hi Friends, while I was preparing for my Fellowship of National Board (FNB) Entrance for Critical Care Medicine; I was totally confused about the kind of questions the Diplomate of National Board (DNB) asks. Cause there is no book, no reference, no site or blog which clearly mentions about them or even gives a few examples.

With the help of my senior, Dr. Suneel Garg, I have managed to collect quite a many of the Multiple Choice Questions (MCQs) that were asked by the DNB for the entrance in the year 2008 and 2009.

So I am starting a new thread “FNB PEARLS” soon, where I will post MCQs asked in the Fellowship of National Board (FNB) Entrance for Critical Care. Not all the MCQs are complete, as it was very difficult to recollect them as they appeared in the exam. But it will definitely give you an idea of the kind of questions asked, the variety, and the topics covered.

I hope it will help all the aspirants preparing for the DNB Fellowship Entrance in Critical Care.

Your queries and suggestions are always welcome. Just post them in the comment box below or you can also write a mail to icucriticalcare@gmail.com.

All the best!!!

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The ICU Book - Paul Marino

• Title: ICU Book
• Edition Description: Third Edition 
• Authors: Marino, Paul L.                 
• Dr. Kenneth Sutin contributed to the final 13 chapters of this edition
• Publisher: Lippincott Williams & Wilkins
• Pub. Date: October 2006
• Copyright ©2007 Lippincott Williams & Wilkins

The preface to the 3rd edition states “ This edition continues the original intent to provide a generic textbook that presents fundamental concepts and patient care practices that can be used in any intensive care unit, regardless of the specialty focus of the unit. Highly specialized areas, such as obstetrical emergencies, thermal injury, and neurocritical care, are left to more qualified authors and their specialty textbooks. The ICU Book has been unique in that it reflects the voice of one author. This edition welcomes the voice of another, Dr. Kenneth Sutin, who added his expertise to the final 13 chapters of the book.”

The preface to the first edition states “ The purpose of The ICU Book is to present this common ground in critical care and to focus on the fundamental principles of critical illness rather than the specific interests for each intensive care unit. This text is problem-oriented rather than disease-oriented, and each problem is presented through the eyes of the ICU physician.”

Review:

I have loved this book for its smoothness, liquidity and easy readability. The free flowing language makes it more gripping. It not only provides a general overview and basic information, but also provides enough detailed and specific information to address almost all questions and problems that arise in the ICU. It is a perfect blend of basic fundamentals and applied physiology with the fully updated, problem-based approach. The author clearly, logically and concisely explains all the fundamental principles of intensive care medicine at the physiologic level.

WIth new chapters in this 3rd edition, like hyperthermia and hypothermia syndromes; infection control in the ICU; and severe airflow obstruction, this book is actually ‘A Complete Book’. This book however does not cover trauma and neuro.

‘The ICU book’ is a perfect way to obtain a fairly broad fund of ICU knowledge without having to stop every other paragraph to analyze and digest the words used to express an idea. I find it very useful for residents and ICU fellows, and certainly for new starters. Practitioners at all levels will find something interesting in this book. It is extremely approachable, and the material is presented in a brief and quick-access format which allows for topic and exam review.

If you want to understand ICU, get this book!

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Swine flu

To view a beautiful, informative video show on Swine flu, click below....

Thanks to my friend, Dr Rahul Bahot for contributing this presentation!

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Solution to Quiz 5:

Ans: Purpura fulminans / Warfarin induced skin necrosis.

Explanation: Purpura Fulminans is an acute syndrome of massive purpura caused by widespread vascular necrosis and hemorrhagic infarction of the skin and frequently of the distal limbs and digits. It may occur at birth as a result of congenital thrombophilia (i.e. homozygous deficiency of protein C or protein S), durin DIC, with severe infections such as meningococcemia, or after the administration of warfarin(i.e. warfarin skin necrosis). Rare causes are chronic alcohol abuse, acetaminophen ingestion, antiphospholipid antibodies with or without transient acquired protein S deficiency after varicella infection. The skin necrosis observed with heparin is another thrombotic manifestation of the heparin-dependent platelet autoantibody syndrome, caused by antibodies against heparin complexed with platelet factor-4.

The early clinical appearance of Purpura Fulminans is transient flushing, followed by petechiae, with or without edema. At presentation, however, the appearance is usually of massive raised and indurated bruises. The periphery of the lesions may be hyperemic; the center may be replaced by hemorrhagic bullae and necrosis of the skin, with sparing of the subjacent musclle. Dependent areas are typically involved, but the predilection for the breasts, fatty tissue (i.e. abdominal wall and buttocks), and penis is not understood. Areas of pressure may be involved.

The histopathological findings are thrombosis of the dermal capillaries and venules, with hemorrhagic infarction. Arteries and arterioles are spared. The thrombi are composed of fibrin, platelets, or a mixture of the two. There are few or no associated inflammatory changes.

There is a general agreement that Purpura Fulminans results from an imbalance of pprocoagulants and the vitamin K-dependent anticoagulant protein C and S.

Numerous cases of skin necrosis have been observed after warfarin administration, especially when a large loading dose has been used. Warfarin-induced necrosis is more common in women. It has a prevalence between 0.01 and 0.1 percent and typically presents 3 to 10 days after treatment initiation. Late-onset warfarin necrosis has been reported in a patient who developed palpable purpura with rapid progression to hemorrhagic bullae on her abdomen and thighs 56 days after initiation of warfarin treatment for heart valve replacement.

The incidence is highest during the first 3 days of drug administration because protein C has a short half life (6 to 9 hrs) compared with the other vitamin K-dependent procoagulant factors IX, X and II. Twenty four hrs after initiation of warfarin, the level of protein C may be less than 10% of normal, whereas functional levels of procoagulant vitamin-K dependent factors (other than factor VII) may be still greater than 50%. The problem is accentuated in individuals who are heterozygous for protein C deficiency, which may account for as muchas 2% of the population. Warfarin induced skin necrosis has been reported occasionally in patients who are protein S deficient. In individuals with normal protein c and S levels, anti-phospholipid antibodies may stimulate a deficiency state by interfering with endothelial-dependent protein C activation by thrombomodulin.

Treatment involves prompt cessation of warfarin therapy and occasionally surgical intervention if gangrenous tissue develops. Methicillin-resistant Staphylococcus aureus infection of widely involved areas of warfarin necrosis can lead to fatal septic shock. If protein C or S def is suspected, it is common practice to begin cautious warfarin therapy while the patient is heparinized. However, anecdotal evidence of skin necrosis, even in this setting, has been reported. The most important method of prevention is the use of low initial dose of warfarin. A loading dose has no physiological advantage and is no longer recommended.

Ref:                                                                                               1. Thrombosis and hemorrhage by Joseph Loscalzo, Andrew I. Schafer, 3rd edition                                                                      2. Williams Hematology, 7th edition

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ACC/AHA/ESC 2006 Guidelines for management of Atrial Fibrillation- ‘Theurapeutic Options’

Pharmacological and Nonpharmacological Therapeutic Options:
Drugs and ablation are effective for both rate and rhythm control, and in special circumstances surgery may be the
preferred option. Regardless of the approach, the need for anticoagulation is based on stroke risk and not on whether sinus rhythm is maintained. For rhythm control, drugs are
typically the first choice and LA ablation is a second-line choice, especially in patients with symptomatic lone AF. In some patients, especially young ones with very symptomatic AF who need sinus rhythm, radiofrequency ablation may be preferred over years of drug therapy. Because the Left Atrial Appendage is the site of over 95% of detected thrombi, this structure should be removed from the circulation when possible during cardiac surgery in patients at risk of developing postoperative AF, although this has not been proved to prevent stroke.

Drugs are the primary treatment for rate control in most patients with AF. While ablation of the AV conduction system and permanent pacing (the “ablate and pace” strategy) is an option that often yields remarkable symptomatic relief, growing concern about the negative effect of long-term RV pacing makes this a fallback rather than a primary treatment strategy. LV pacing, on the other hand, may overcome many of the adverse hemodynamic effects associated with RV pacing.

Heart Rate Control Versus Rhythm Control:

Distinguishing Short-Term and Long-Term Treatment Goals:

For patients with symptomatic AF lasting many weeks, initial therapy may be anticoagulation and rate control, while the long-term goal is to restore sinus rhythm. When cardioversion is contemplated and the duration of AF is unknown or exceeds 48h, patients who do not require long-term anticoagulation may benefit from short-term anticoagulation. If rate control offers inadequate symptomatic relief, restoration of sinus rhythm becomes a clear long-term goal. Early cardioversion may be necessary if AF causes hypotension or worsening HF, making the establishment of sinus rhythm a combined short- and long-term therapeutic goal. In some circumstances, when the initiating pathophysiology of AF is reversible, as for instance in the setting of thyrotoxicosis or after cardiac surgery, no long-term therapy may be necessary.

AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) found no difference in mortality or stroke rate between patients assigned to one strategy or the other. The RACE (Rate Control vs. Electrical cardioversion for persistent atrial fibrillation) trial found rate control not inferior to rhythm control for prevention of death and morbidity.

The AFFIRM, RACE, PIAF (Pharmacologic Intervention in Atrial Fibrillation), and STAF (Strategies of Treatment of Atrial Fibrillation) studies found no differences in quality of life with rhythm control compared with rate control. Rhythm control in the PIAF and How to Treat Chronic Atrial Fibrillation (HOT CAFÉ) studies resulted in better exercise tolerance than rate control, but this did not translate into improved quality of life.

Ref: J. Am. Coll. Cardiol. 2006;48;e149-e246

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Quiz 5:

A young male with Rheumatic Heart Disease with Mitral Stenosis, developed Atrial fibrillation. He was started on Tab Warfarin. After 3 days,

he reported  to the emergency ward with petechiae and mild edema over his feet, which gradually progressed as shown in the pictures below:

Picture1A----1B-----1C----1D

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TRALI - Pathophysiology

The lung appears to be the main site for leukocyte activation and bears the majority of tissue damage in TRALI. Possible explanations for this include that the pulmonary microcirculation is the first to encounter transfusion-associated antibodies or immune complexes and that it also contains pulmonary macrophages that can become activated.

The pathogenesis of TRALI depends on the blood product transfused, the underlying mechanism, and “threshold effects” that (may) allow more than 1 mechanism to participate in the lung injury. Nearly all plasma-containing blood products and a variety of blood components have been implicated in TRALI pathogenesis, including whole blood, packed RBC, FFP, platelet concentrates or apheresis, granulocytes, cryoprecipitate, intravenous immunoglobulin, and bone marrow stem cells. Generally, TRALI reactions have not been attributed to washed red cells, albumin, and clotting factor concentrates.

The EHN (European Haemovigilance Network) subtypes TRALI based on underlying mechanism into immune (antibody mediated) or nonimmune TRALI (non-antibody mediated). Others, however, favor a “Two hit” model of TRALI pathogenesis that can apply to both antibody mediated and non-antibody mediated TRALI cases.

Ref: Journal of Intensive Care Medicine / Vol. 23, No. 2, March/April 2008

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ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation- Clinical Evaluation

AHA 2006 guidelines for management of Atrial Fibrillation

Clinical Evaluation in Patients With AF:

Minimum evaluation:

1. History and physical examination, to define

Presence and nature of symptoms associated with AF

Clinical type of AF (first episode, paroxysmal, persistent, or permanent)

Onset of the first symptomatic attack or date of discovery of AF

Frequency, duration, precipitating factors, and modes of termination of AF

Response to any pharmacological agents that have been administered

Presence of any underlying heart disease or other reversible conditions (e.g., hyperthyroidism or alcohol consumption)

2. Electrocardiogram, to identify

Rhythm (verify AF)

LV hypertrophy

P-wave duration and morphology or fibrillatory waves

Preexcitation

Bundle-branch block

Prior MI

Other atrial arrhythmias

To measure and follow the R-R, QRS, and QT intervals in conjunction with antiarrhythmic drug therapy

3. Transthoracic echocardiogram, to identify

Valvular heart disease

LA and RA size

LV size and function

Peak RV pressure (pulmonary hypertension)

LV hypertrophy

LA thrombus (low sensitivity)

Pericardial disease

4. Blood tests of thyroid, renal, and hepatic function

For a first episode of AF, when the ventricular rate is difficult to control

Additional testing

One or several tests may be necessary.

1. Six-minute walk test

If the adequacy of rate control is in question

2. Exercise testing

If the adequacy of rate control is in question (permanent AF)

To reproduce exercise-induced AF

To exclude ischemia before treatment of selected patients with a type IC antiarrhythmic drug

3. Holter monitoring or event recording

If diagnosis of the type of arrhythmia is in question

As a means of evaluating rate control

4. Transesophageal echocardiography

To identify LA thrombus (in the LA appendage)

To guide cardioversion

5. Electrophysiological study

To clarify the mechanism of wide-QRS-complex tachycardia

To identify a predisposing arrhythmia such as atrial flutter or paroxysmal supraventricular tachycardia

To seek sites for curative ablation or AV conduction block/modification

6. Chest radiograph, to evaluate

Lung parenchyma, when clinical findings suggest an abnormality

Pulmonary vasculature, when clinical findings suggest an abnormality

Management:

Management of patients with AF involves 3 objectives—

1. Rate control,

2. Prevention of thromboembolism, and

3. Correction of the rhythm disturbance, and these are not mutually exclusive.

The initial management decision involves primarily a rate-control or rhythm-control strategy.

Under the rate-control strategy, the ventricular rate is controlled with no commitment to restore or maintain sinus rhythm.

The rhythm-control strategy attempts restoration and/or maintenance of sinus rhythm. The latter strategy also requires attention to rate control. Regardless of whether the rate-control or rhythm-control strategy is pursued, attention must also be directed to antithrombotic therapy for prevention of thromboembolism.

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TRALI - Definition

Transfusion-related acute lung injury (TRALI)

An international consensus conference on TRALI held in Canada in 2004 advised that TRALI should be recognized as a clinical syndrome and not as a disease with a single etiology.

Definition:

The Canadian consensus conference defined TRALI as having the following criteria:

(a) acute onset,

(b) hypoxemia as defined by a PaO2/FiO2 ≤300 or oxygen saturation by pulse oximetry less than 90% on room air,

(c) bilateral lung infiltrates on chest X ray,

(d) no evidence of left atrial hypertension,

(e) occurrence during or within 6 hours of transfusion, and

(f) no preexisting ALI before transfusion or temporal relationship to an alternative ALI risk factor .

Possible TRALI:

In cases of TRALI occurring in the setting of transfusion and an alternative risk factor for ALI, a designation of “possible TRALI” was added. These alternative risk factors included a variety of conditions that may directly or indirectly induce lung injury, such as pneumonia, pulmonary contusion, and sepsis.

Limitations of the definition:

(1) This definition, however, does not acknowledge the effects of positive end expiratory pressure on the PaO2/FiO2 ratio.

(2) An additional important limitation of this definition is that it excludes patients with preexisting ALI, whose lung injury worsens after transfusion.

Ref: Journal of Intensive Care Medicine / Vol. 23, No. 2, March/April 2008

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Answer to Quiz 4:

Ans: Marfan Syndrome with Aortic Root Dilatation causing Aortic Regurgitation

Explanation:

MARFAN SYNDROME is characterized by

(a) Skeletal Effects:

Patients have long, thin extremities, frequently associated with loose joints. The fingers and hands are long and slender and have a spider-like appearance (arachnodactyly). Many patients have severe chest deformities, including depression (pectus excavatum), protrusion (pectus carinatum), or asymmetry. CT or MRI examinations of the lumbar sacral region frequently reveals enlargement of the neural canal, thinning of the pedicles and laminae, widening of the foraminae, or anterior meningocele (dural ectasia). High-arched palate and high pedal arches or pes planus are common. A few patients have severe joint hypermobility.

(b) Cardiovascular Features:

Cardiovascular abnormalities are the major source of morbidity and mortality.

Mitral valve prolapse develops early in life and progresses to mitral valve regurgitation of increasing severity in about one-quarter of patients.

Dilatation of the root of the aorta and the sinuses of Valsalva are characteristic and ominous features of the disease that can develop at any age. The rate of dilatation is unpredictable, but it can lead to aortic regurgitation, dissection of the aorta, and rupture.

(c) Ocular Features:

Downward displacement of the lens is common. It is usually not progressive but may contribute to the formation of cataracts. The ocular globe is frequently elongated, most patients are myopic, and some develop retinal detachment. A few patients have lattice degeneration and retinal tears; most have adequate vision.

(d) Other Features

Striae may occur over the shoulders and buttocks. A number of patients develop spontaneous pneumothorax. Inguinal and incisional hernias are common. Patients are typically thin with little subcutaneous fat, but adults may develop centripetal obesity.

Treatment

Propranolol or other -adrenergic blocking agents are effectively used to lower blood pressure and thereby delay or prevent aortic dilatation. Surgical correction of the aorta, aortic valve, and mitral valve has been successful in many patients, but tissues are frequently friable.

The scoliosis tends to be progressive and should be treated by mechanical bracing and physical therapy if >20° or by surgery if it progresses to >45°. Dislocated lenses rarely require surgical removal, but patients should be followed closely for retinal detachment.

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