Thanks Amanda for sharing your case of a middle aged male with a past history of diabetes and HTN presenting with diplopia found to have a sixth nerve palsy due to a pontine infarct.
- Your approach to diplopia should be the same as we approach any neurologic deficit – Localize the lesion along the anatomic pathway
- Peripheral cranial nerve
- Both a mononeuropathy or external compression of the cranial nerve
- Extraocular muscles
- neuromuscular junction
- Globe (retina, cornea, lens)
- Monocular diplopia vs. binocular diplopia
- Binocular diplopia: If the diplopia is present only when both eyes are open then the diplopia is due to ocular misalignment
- Monocular: Most often due to diseasse of the cornea or lens, less commonly the retina or cerebral lesion
- Extraoccular muscle weakness can be subtle. LT pearl: when testing EOM, move your finger fast as this will be more likely to demonstrate subtle weakness than slow movements.
- Cranial nerve palsies
- 3rd nerve: longest cranial nerve after exiting the brainstem, more commonly affected by compression from an aneurysm or tumor. When a third nerve palsy is due to microinfarction from diabetes it typically spares the pupil. Therefore pupillary defects should raise your suspicion for intracranial lesion
- 4th nerve: Most prone to injury from trauma and more rarely affected by microinfarction
- 6th nerve: Most commonly affected
Check out this excellent chart from EB Medicine reviewing CN III, IV, and VI palsies.
- Code stroke: time sensitive interventions may be changing in the future
- The latest trials are showing benefit to endovascular intervention in patients with large vessel occlusion within 6 hours of symptoms onset even after tPA administration.
- Newer trials are investigating endovascular intervention up to 24 hours after symptom onset
- Risk of future stroke after TIA: Use the ABCD2 score
- This helps estimate the risk of stroke within the next 2 days after TIA
- In patients with a risk < 1%, outpatient work-up may be appropriate
- Goal is to get work=up completed within 24 hours
Evernote link: https://www.evernote.com/l/AMphZJl3GedO_Zz0p6Mjya3DIEWYfNB-uB8
Thank you Kelly for presenting your patient with subacute worsening of chronic low back pain without red flag signs or symptoms found to have surprising findings on MRI of L3-L4 instability with spondylolithesis and edema causing mass effect on the spinal cord.
- Don’t forget your physical exam maneuvers to assess for radiculopathy: straight leg raise (L4-S1); opposite straight leg raise (L5-S1); and reverse straight leg raise (L3-L4).
- Order spinal MRI for patients with red flag signs or symptoms, pain that is progressive, or when it will change treatment (including referral for spinal injections or surgery)
- Inflammatory markers may be helpful in determining who needs an urgent MRI
The Physical Exam Maneuvers for the evaluation of Low Back Pain
- Straight leg raise:
- How to do: Patient supine, examiner raises affected side leg keeping it straight up to 60 degrees
- Positive test: reproduces pain on side of leg raised
- Suggests L4-S1 nerve root pain if radiates below the knee
- Sensitivity = 80%, specificity = 40%
- Reverse Straight Leg Raise (femoral stretch test)
- How to do: Patient lying prone passively extending the hip and leg straight up off the plane of the table
- Suggests L3 nerve root pathology if pain radiates into the anterior thigh
- Opposite Straight leg raise
- How to do: Patient supine, raise opposite side leg, keeping it straight
- Positive if pain reproduced on the affected side
- More specific test for L5-S1 radiculopathy
- An L5-S1 radiculopathy is 95% sensitive for lumbar disk herniation (thus, the absence of radiculopathy almost rules-out a herniated disk)
- FABERE (Flexion, Abduction, External Rotation, and Extension)
- Consider performing if evaluating for hip or SI joint as cause of pain
- How to do: Hip is externally rotated with the ipsilateral knee flexed at 90 degrees and placed on the opposite knee. Then apply downward pressure on the leg towards the examine table. Goal of getting leg parallel to exam table
- If pain: indicates SI joint disease
- If limited ROM: indicates hip, SI, or iliopsoas spasm
When to get imaging for low back pain?
- Red flag signs or symptoms
- If low back pain is not improving after conservative management and the patient is a candidate for surgery or epidural spinal injections
- Imaging choice
- MRI is ideal
- Can consider a CT if a patient cannot get an MRI
- Xrays may be helpful to evaluate for compression fracture and degenerative changes
When should I order inflammatory markers?
- Consider ordering if you are concerning about do not miss diagnoses including seronegative spondyloarthropathies, malignancy, or infection.
- Check out this article on the use of a clinical decision support tool utilizing risk factors and ESR/CRP to evaluate for spinal epidural abscess
- The bottom line: The use of a clinical decision guideline for patients presenting to the ED with low back pain involving risk factors and ESR/CRP to determine who should receive urgent MRI decreased the time to diagnosis of spinal epidural abscess and decreased the incidence of neurologic deficits at the time of diagnosis.
Check out the ACP guidelines on the treatments for chronic low back pain.
Click here for an Evernote on Low Back Pain
Case Summary: Thank you Alicia for presenting your clinic patient a 20 yo F with refractory epilepsy presenting with subacute migratory polyarthritis after starting Oxcarbazepine concerning for Drug-Induced Lupus on top of SLE.
- Patients with drug-resistant epilepsy should be seen at a specialized epilepsy center
- Thanks Chris Sha for teaching us the top three causes of infectious polyarthritis: Disseminated Gonococcal disease, spirochetes, and viral (HIV, HBV)
- Approach to arthritis: Consider basing it on number of joints and inflammatory vs. non-inflammatory
- Differentiating drug-induced lupus from SLE is based on clinical picture and laboratory findings.
- Anti-TNF drugs are increasing in use and can cause an atypical presentation of drug induced lupus.
- No set definition, but has been proposed that drug-resistant epilepsy may be defined as failure of adequate trials of two antiseizure drug schedules (whether as monotherapies or in combination) to achieve sustained seizure freedom
- Other forms of treatment may be considered; vagal nerve stimulation, surgery
- If seizures are not controlled after 12 months, the patient should be referred to a specialized epilepsy center
- Ambulatory EEG monitoring?
- More cost effective than in-hospital EEG. Can increase the yield of detecting a seizure due to longer time on monitors and patient’s are less sleep deprived when sleeping in their normal environment.
- Gold standard for differentiating non-epilieptic seizures from epileptic seizures is still in-patient EEG.
Flashback to Katie Auriemma’s post on an approach to polyarthritis from the Moffitt Pearls earlier this week.
Drug-induced lupus (DIL)
- Common meds: procanamide, hydralazine, penicillamine, INH
- Also seen with TNF-alpha inibitors
- Can be more atypically presentation of DIL including negative anti-histone antibodies, hypocomplementemia positive dsDNA antibodies
- More often causes superficial lupus symptoms (joint pain, rash) over visceral involvement (anemia, nephritis, serositis, etc)
- History of taking a known offending medication
- Development of one feature of lupus
- Serology: Positive ANA.
- Positive anti-histone antibody is strongly suggestive.
- Can be seen in idiopathic SLE but those patients will also have positive subserologies
- You can also see a positive ANCA
- Resolution of symptoms within weeks of stopping the offending agent
How do I differentiate between SLE and DIL?
||Average age of onset 20 -30 y
More likely to affect African Americans than Caucasians
Female: Male 9:1
|Average age of onset 50 -70 y
More likely to affect Caucasians than African Americans
Female: Male 1:1
||ANA positive > 95%
Anti-histone antibodies in 50%
Anti-dsDNA in 80%
Low C3/ C4
|ANA positive in > 95%
Anti-histone antibodies in > 95%
Anti-dsDNA can be present
Thanks to Akshai for presenting an interesting case of a 41 yo F with subacute bilateral leg swelling found to have nephrotic syndrome in the process of being evaluated for the underlying cause.
- Proteinuria can be broken into 4 causes: Overflow, glomerular, tubular, post-renal
- When concerned about a glomerular process use your clinical findings and UA to help you determine if the picture is more consistent with nephritic vs. nephrotic
- Nephritic Syndrome is often diagnosed with lab tests whereas nephrotic syndrome usually needs a biopsy to confirm the underlying cause
- Treatment of nephrotic syndrome: ACEi/ARB for proteinuria, loop diuretic and salt restriction for edema, statin if hyperlipidemia does not resolve, warfarin if thrombosis.
What is the usefulness of BNP for lower extremity edema?
- Breathing Not Properly Study: In a patient presenting with dyspnea a BNP cut off of > 100 can be helpful in determining heart failure over pulmonary cause of dyspnea
- The ACC/AHA 2017 Focused Update gives a Class I recommendation for measurement of BNP in patients presenting with dyspnea, to support a diagnosis or exclusion of HF.
- No studies have looked at BNP in a patient presenting with lower extremity edema as a predictor for heart failure
- Can be elevated for a variety of reasons: renal failure, cirrhosis, sepsis, anemia, stroke, OSA, PE and more.
Causes of Proteinuria (Forgive my powerpoint nephron drawing!)
Nephritic vs. Nephrotic?
Disease of the glomerulus can be nephrotic or nephritic. Use your clinical findings and UA to help you differentiate.
||UA and urine sediment Findings
||Asymptomatic microscopic hematuria and proteinuria
Occassionally gross hematuria
|RBCs, dysmorphic RBCs, RBC casts
|Inflammatory lesions in less than one half of glomeruli
|RBCs, dysmorphic RBCs, RBC casts
Heavy Proteinuria (>1.5g/day)
|Diffuse glomerular disease
|Heavy proteinuria (oftenr >3.5g/day)
Few casts or cells
|Varies based on underlying cause
Nephrotic Range Proteinuria work-up for the PCP:
- Send ANA, A1c, HIV, RPR, and Hepatitis serologies.
- Refer to renal for likely renal biopsy.
- Renal biopsy is often needed in adults whereas children are often treated with empiric steroids for presumed minimal change disease.
Treatment of Nephrotic Syndrome
- The degree of proteinuria is a predictor of renal failure. Treatment can reduce progression.
- ACEi/ARBs – BP effects are immediate but proteinuria effects can take days-weeks
- Volume Overload:
- Due to sodium retention (not oncotic pressure from protein loss)
- Diuretics; Slow diuresis to prevent hypovolemia, start with loop diuretics but may also need thiazide diuretics
- Often reverse when underlying cause is treated and reversed
- Most patients will need statin
- Dietary modification does not help
- More common in membranous nephropathy
- If thrombosis, treat with warfarin
- Unclear if prophylactic anticoagulation benefit outweighs risks, practice varies amongst nephrologists
- Treat underlying cause if identified
LT Pearls from the daily ditty about bacterial meningitis
- Listeria meningitis is the one cause of bacterial meningitis that can have a lymphocytic predominant pleocytosis
- CSF findings in Listeria meningitis can range from 100% PMNs to 100% monocytes
Thank you to Colin for presenting a patient seen in liver clinic with a history of alcoholic cirrhosis who recently stopped drinking found to have hepatocellular injury likely due to Disulfiram.
- DILI can be due to many different medications. To help you narrow your list, focus on the pattern of injury (hepatocellular vs. cholestatic) and the time course (acute vs. chronic)
- Disulfiram can cause an acute hepatocellular injury and should be used with caution and monitoring in patients with a cirrhosis
- In patients with cirrhosis with thrombocytopenia without anemia consider other sites of Epo production such as in HCC
- First line medication assisted treatment for alcohol use disorder include Naltrexone, Acamprosate, and Disulfiram. Choose a medication based on patient goals and side effect profile.
Drug Induced Liver Injury (DILI)
- Depending on the offending agent:
- Can see acute (< 3 months) or chronic liver injury (>3 months) dependi
- Can see hepatocellular injury or cholestatic injury
- Symptoms can vary based on severity of injury and pattern of injury
- Patients are often asymptomatic
- Can have non-specific symptoms including nausea, malaise, anorexia,
- Can also cause present with symptoms similar to other causes of acute or chronic liver injury such as jaundice, pruritus, dark urine, pale stools
- Clinical diagnosis which can be hard to make
- Known offending medication started prior to laboratory abnormalities
- Stopping the offending agent leads to improvement in liver injury
- Negative work-up for other causes
- Assessment of other causes should be guided by history, physical exam, labs
- If still uncertain the patient may need a liver biopsy
- Medications that can cause DILI
- There are over 1000 known medications and supplements that can cause DILI
- Most common: Acetaminophen followed by antibiotics
- Use the pattern and time course of liver injury to help you narrow your list of offending agents
- Great resource for medications and supplements that can cause liver injury by the NIH: https://livertox.nlm.nih.gov/index.html
- Disulfiram induced liver injury
- Seen within 2-12 weeks of starting Disulfiram
- Disease severity can range from asymptomatic elevations in aminotransferases to acute liver failure and death
- Can have immuno-allergenic fevers with fever, eosinophilia and rash
- No hepatic dose adjustment for patients with liver failure but should be used with caution and should monitor for hepatotoxicity
Lab abnormalities in cirrhosis
- Pearl from LT: In patients with cirrhosis who have a thrombocytopenia with a normal hemoglobin think about Epo production from sites other than bone marrow (such as in HCC)
- The classic LFT pattern in patients with alcoholic cirrhosis of AST:ALT of >2 is often maintained when there is another acute insult not related to alcohol
- There is a hypothesis that the AST:ALT ratio in alcoholic use is due to a deficiency of pyridoxal 5′-phosphate in alcoholics, a cofactor for the enzymatic activity of ALT. This may explain why the pattern is maintained when there is a separate liver insult.
- Shoutout to Rabih for these awesome pearls about patterns of LFT abnormalities.
Medications for Alcohol Use Disorder (AUD)
||Mechanism of Action
||Adverse drug effects and contraindications
||Who should I use this in?
||Blocks of the mu-opioid receptor involved in the rewarding effects of drinking
ALT or AST > 150s
Use of Opiates
|Reduces relapse to heavy drinking (See 1, 2)
Reduces alcohol consumption compared to placebo
|Helpful in reducing the amount of alcohol
Less effective for abstinence
|Depot Naltrexone (Vivitrol)
||Same as above, but long acting requiring monthly IM injection
||Same as above
||Decreased rate of heavy alcohol use
Increased the number of abstinent days
|If covered by insurance and patient prefers long acting form
||Acts at GABA and glutamate neutrotransmitters –> reduce symptoms of protracted abstinence
||Three times daily dosing
Safe to use in patients with liver failure
Renal dose adjustment required
Contraindicated in renal failure
|Increased proportion of heavy drinkers who maintained abstinence in European study
Not demonstrated in these two US studies
|Consider if the goal if abstinence and patient cannot tolerate other medication options
||Inhibits aldehyde dehydrogenase –> accumulation of acetaldehyde –> flushing, nausea, palpitations, headache if alcohol is consumed
||Contraindicated in severe heart failure or CAD
Avoid in pregnant or nursing women
Monitor for hepatotoxicity
|Most studies have shown it to be no more effective than placebo in maintaining abstinence, but may reduce drinking days
Most effective when given in monitored setting such as by spouse (27)
|Patients highly motivated to have complete abstinence
Patients can use periodically for high risk social situations
||Acts at propionic acid, GABA and glutamate receptors
||SE: Cognitive impairment, weight loss, headache, depression.
Off label use
Titrate gradually over several weeks
|Decreased consumption in patients with SUD, similar effect as naltrexone
||Off label use, second line medication
||Structurally related to GABA
||SE: Sedation and dizziness
|Higher abstinence rates and decreased alcohol consumption in small trials
||Off label use, second line medication
||SE: nausea, vertigo, sleepiness
Generally well tolerated
||Limited evidence of efficacy, off label use
||SE: nausea, insomnia, fatigue, psychiatric symptoms
|Taken as needed shown to reduce number of heavy drinking days
||Not available in the US
||Inhibits breakdown to serotonin
||Reduced alcohol intake in patients with depression and alcohol use
||No efficacy demonstrated in patients without depression
||5-HT3 receptor antagonist
||SE: diarrhea, headache
|Some demonstrated effectiveness in subgroups: early onset alcohol use and patients with specific genetic variant of 5-HT3 receptor
||Off label use, only demonstrated efficacy in sub-groups
The VA has lots of resources for patients with substance use disorders including: PES, Addiction consult, OTOP, and inpatient rehab.
Check out the California Society of Addiction Medicine’s guide for primary care physicians regarding patients who drink too much.
Thanks Beth for the awesome case of a 90 yo F with pmhx of HTN, CKD presenting after multiple falls who developed urinary retention and fecal incontinence found to have cervical spine myelopathy from spinal stenosis.
Key Learning Points
- Approach to a patient with falls: Consider a physiologic approach thinking about the systems that need to be functioning properly to walk: cognition, motor strength, sensation, musculoskeletal apparatus, cardiovascular fitness, navigable environment
- Use the CHIP rule for determining which patients presenting to urgent care or the ambulatory setting need a head CT. The Canadian head CT rule is for patients with loss of consciousness
- The Timed Get-Up and Go test is helpful for assessing falls risk
Falls in the elderly
Step 1– Assess if the fall is consistent with syncope or pre-syncope vs. mechanical cause.
Step 2 – Assess the patient for injuries related to the fall.
- When to get a head CT?
- Decision rules to help us decide who needs a head CT after a fall. The Canadian CT Head Rule is often applied in the Emergency setting and only applies to patients with loss of consciousness. The Canadian head CT rules are the most widely validated.
- For the ambulatory and urgent care setting you could consider using the CHIP rule because it applies to patients without loss of consciousness. Note that the CHIP rule recommends head CT in patients over 60 years of age. This is a nice reminder that our older patients are at a much higher risk of subdural hematomas due to cerebral atrophy even with minor head trauma.
Step 3 – Evaluate for the etiology of the fall
Falls in the elderly are multifactorial and each fall could have a different etiology so needs to be evaluated separately.
You can use a physiologic approach to falls. Think about all the systems you need to walk (which is actually a very complex task!):
- Dementia from any cause
- Dementias associated with decreased physical functioning: parkinsons, spinal muscle atrophy
- Normal pressure hydrocephalus
- Drugs and toxins: alcohol, medications (see below)
- Motor strength
- Primary muscle disease
- Neuromuscular junction disorder
- Peripheral neuropathy
- Poor vision
- Vestibular dysfunction
- Musculoskeletal apparatus
- Ligamentous Injury
- Cardiovascular fitness
- Orthostatic hypotension
- Navigable environment
- Lighting, irregular floor surfaces, unsafe stairs, cords and carpets
- Medications (always include as a category of your differential in the elderly!)
- Sedative-hypnotics, TCAs, antihypertensives, cardiac medications, corticosteroids, NSAIDs, anticholinergic meds, hypoglycemic agents
Timed Up and Go Test
- Can be used to help with the global gait assessment
- How to perform: Instruct the patient to get out of the chair (without using armrests), stand up, walk forward 10 feet, turn around and walk back to chair, sit down.
- Normal is < 10 seconds and indicates the patient is mobile. > 20 seconds indicates the patient is variably mobile. > 30 seconds indicates impairments in mobility
- Aside from timing, observing the patient’s ability to perform each maneuver of the test can help you determine what area the patient is deficient .
Interventions for abnormal results of the Timed Up and Go test (Table copied from Preventing Falls in the Geriatric Population reference below)
|Difficulty rising from chair
||Proximal muscle weakness
||PT referral for lower extremity strengthening
|Staggering or reported dizziness upon rising
||Check orthostatic vital signs; review medications that may contribute to orthostasis
|Pill-rolling tremor, stooped posture, shuffling/festinating gait
||Consider neurology referral
|Increased sway, magnetic gait
||Possible normal pressure hydrocephalus
||Ask about urinary incontinence and memory issues. If these are highly suspected, consider head CT
||Possible peripheral neuropathy, cerebrovascular disease
||Consider neuropathy workup, examination of feet, PT referral for assistive device
|Slow, antalgic gait
||Pain from osteoarthritis, peripheral neuropathy, podiatric disorders
||Pain control, examination of feet
Differential for Urinary Retention in Women
- Detrusor underactivity: aging, DM, neurologic disease (stroke, spinal cord compression),
- Outflow obstruction: pelvic organ prolapse, pelvic masses
- Functional: Dysfunctional voiding, Detrusor sphincter dyssynergia, bladder neck obstruction
- Meds: Most common: anticholinergic and sympathomimetic
- Infection – UTI, genital herpes
Smits M, et al. Predicting intracranial traumatic findings on computed tomography in patients with minor head injury: the CHIP prediction rule. Ann Intern Med. March 20, 2007;146(6):397–405.
AAFP article on falls in the elderly: http://www.aafp.org/afp/2000/0401/p2159.html
Thanks Tim for presenting the case of a 76 yo M with a pmhx of AS s/p valve replacement presenting to clinic with subacute fatigue, fevers, and weight loss found to have endocarditis likely from one of the HACEK organisms with final culture results still pending.
Key Learning Points
- If your baseline work-up (see details below) of weight loss in the elderly is normal, the likelihood of malignancy is very low. There is no need for further testing, but you should continue with close follow-up.
- TAVR is indicated for severe AS with symptoms and prohibitive surgical risk but also been shown to be non-inferior for high and intermediate surgical risk patients
- Complications of artificial heart valves include: infection, thromboembolism, obstruction, regurgitation, and hemolytic anemia
- HACEK organisms most often will grow in blood cultures but can take longer than our more common strep and staph species.
Weight loss in the elderly (flash back to report pearls from 6.7.17!)
- Work-up is directed by history and physical but at a minimum should include: CBC, BMP, LFTs, TSH, CRP, ESR, LDH, UA, CXR, FOBT, maybe abdominal ultrasound
- A prospective study demonstrated that if this baseline work-up is normal none of the patients went on to have malignancy demonstrated on additional testing. Therefore if the baseline work-up is normal, no further testing is necessary but continue with close follow-up.
- AAFP Practice guidelines for Unexplained Weight Loss in Older Adults
Artifical Heart Valves
- Types of artifical valves
- When choosing between bioprosthesis vs. mechanical valves it should be a shared decision with the patient. Things to consider:
- Longevity of the valve: Mechanical heart valves last 20-30 years vs. 10-15 years with bioprosthetic valves. Consider mechanical heart valves most often in patients < 60 years and bioprosthetic valves in patients > 70 years
- Anticoagulation: Required in mechanical valves
- Ball and cage valves: Phased out ~ 20 years ago, very durable but more complications including thromboembolism, migration of the whole valve, and the ball getting stuck in the cage
- Methods for valve replacement: Surgical vs. TAVR
- The PARTNER trial demonstrated non-inferiority of TAVR vs. SAVR for high surgical risk patients
- Indications for TAVR:
- Severe AS with symptoms and prohibitive risk for surgical replacement
- Severe AS with symptoms and high surgical risk
- Patients could also undergo SAVR
- The PARTNER trial demonstrated non-inferiority of TAVR vs. SAVR for high surgical risk patients
- TAVR is a reasonable alternative for patients at intermediate surgical risk depending on patient specific variables
- PARTNER II trial demonstrated non-inferiority for TAVR vs. SAVR in intermediate risk patients
- Contraindicated for bicuspid aortic valves
- TAVR has not been studied in asymptomatic patients and therefore is not recommended. Patients should be monitored clinically for development of symptoms.
- Complications of artificial valves
- Prosthetic valve thrombus leading to obstructive symptoms
- Valve obstruction
- Can be due to: leaflet fibrosis, Calcification, pannus formation, or thrombus
- LT taught us about a patient he had with pannus formation which is fibrous tissue ingrowth around the valve. This is much less common than other causes of obstruction
- For dx: get echo to determine valve gradient and consider CT to better characterize the mass on the valve. The patient may need surgery for diagnosis and treatment.
- Valve regurgitation
- Can occur both through the valve itself and paravalvular
- Due to leaflet degeneration, calcification, endocarditis, thrombus, or pannus formation
- Hemolytic Anemia
- HACEK organisms: Although historically classified as culture negative endocarditis, our current culture methods can grow these organisms but they take longer to grow (Median time is ~ 3 days).
- Most common cause of culture negative endocarditis: fastidious organisms and strep species in patients already on antibiotics.
- Diagnosing Q fever endocarditis
- Phase I IgG antibody titer should be > 800
- Duke’s criteria include microbiological evidence of infection. Major criteria: IgG Phase I titer > 6400. Minor criteria is a titer > 800
- Shout out to Rabih’s prior morning report pearls on endocarditis breaking the differential down between culture positive and culture negative endocarditis.
PARTNER Trial: Smith, Craig R., et al. “Transcatheter versus surgical aortic-valve replacement in high-risk patients.” New England Journal of Medicine 364.23 (2011): 2187-2198. http://www.nejm.org/doi/full/10.1056/NEJMoa1103510#t=article
PARTNER II Trial: Leon, Martin B., et al. “Transcatheter or surgical aortic-valve replacement in intermediate-risk patients.” N Engl J Med 2016.374 (2016): 1609-1620. http://www.nejm.org/doi/full/10.1056/NEJMoa1514616
AHA/ACC Guidelines for management of Valvular Heart Disease: http://circ.ahajournals.org/content/early/2017/03/14/CIR.0000000000000503