Day #321 - Polyarticular Gout

Today we discussed a patient with polyarticular gout presenting with fever and multiple swollen joints.

Precipitants:

Drugs: HCTZ, other diuretics, ASA, pyrazinamine, allopurinol, cyclosporin, other
Foods: Alcohol (red wine), Red Meat, Cheeses
Diseases: Myeloproliferative disorders, hematologic malignancies, renal failure

Diagnosis (how to do an arthrocentesis):

Synovial fluid cell count usually in the 10,000-20,000 range but can be as high as 100,000.

Crystals should be seen -- negatively birefringent needle shaped crystals which are intracellular

Acute Treatment (usually one of):


NSAIDS: I.e. Naproxen 500mg PO BID
Steroids: Intrarticular (i.e. depomedrol 20-40mg) or systemic prednisone (i.e. 40mg x 3 days then taper by 10mg every three days)
Colchicine: colchicine 0.6mg po q1h x3 (diarrhea, nausea) then 0.6 OD-BID (renal dosed)

Long term Treatment:
Weight loss, avoidance of foods and drugs that precipitate

Initiate low dose colchicine if you are going to start anti-hyperuric medications to avoid precipitating an attack

Generally initiate therapy if one/more of: (i) urate nephropathy or recurrent stones (ii) destructive tophi (iii) greater than three attacks per year (iv) greater than 1100mg urinary urate per day

Some advocate for use of 24h urine urate -- if >800 then uricosuric therapy is contra-indicated. Titrate to uric acid less than 360umol/L

Uricosuric therapy:

Probenecid start 250mg BID titrate to 500-1000 BID

Consider vitamin C 500mg PO OD

Consider losartan as an antihypertensive if needed (has uricosuric effect)

Consider fenofibrate

Xanthine Oxidase Inhibition:

Allopurinol 100mg PO OD titrate to effect (usual dose ~ 300mg/day)

I have previously blogged about the approach to the mono/oligo arthritis (and septic arthritis) here.

Day #231 - Cavitary Lung Lesions

Today we discussed an immunosuppressed patient with bilateral upper lobe cavitary lung lesions. The differential diagnosis for such lesions in the immunocompetent includes:








Infection:

• TB or Atypical Mycobacterial Disease
• Cavitary Pneumonia
  
  • Gram negatives (Klebsiella, E. Coli, Pseudomonas)
  • Gram positives (Staphylococcus aureus (particularly CA-MRSA), group A streptococci)
  • Anaerobes (Lung Abscess)
• Fungal: Aspergillosis, Histoplasmosis, Coccidiomycosis, Blastomycosis, Cryptococcus
• PCP
  
• Superinfection/Colonization of an existing cavity
  
  • Aspergilloma ("fungus ball" or mycetoma)
• Septic pulmonary emboli with cavitation

Inflammatory:

• Wegner's Granulomatosis
• Rheumatoid Arthritis
• Sarcoidosis (rare)
  

Vascular

• Pulmonary Infarct

Malignancy:

• Bronchoalveolar carcinoma
• Bronchogenic carcinoma
  
• Squamous cell cancer of lung
  
• Cavitating metastases

Anotomical:

• Cystic Bronchiectasis

Day #139 - Atrial Fibrillation

Today we talked about a case of rapid atrial fibrillation.

The ACC guidelines for atrial fibrillation are here, and the ACLS tachycardia algorithm is here.

Is the AF causing severe CHF, hypotension or angina? If so manage as unstable. Otherwise manage as stable.

Unstable:

• DC Cardioversion

Stable:

• Does the patient have pre-excitation or a grade III/IV LV?
  
  • Amiodarone 150mg IV over 10 minutes, can repeat, then give 360mg IV over 6h then 540mg IV over 18h loading. Risk of cardioversion.
• No WPW or grade III/IV LV:
  
  • IV beta blocker (like metoprolol 5mg IV over 2 mins, can repeat q 5 mins x 3)
  • IV calcium channel blocker (diltiazem 0.25mg/kg IV over 2 mins, can repeat in 10 mins with 0.35mg/kg IV)
  • Follow up with oral agent of same class
• There is evidence that IV magnesium can be effective as a rate control agent, either alone or in combination.
  
• Afib of less than 48h duration (or no thrombus on TEE) can consider cardioversion either electrical or chemical.
• Does this patient need anticoagulation?
  
  • CHADS2 score if greater than or equal to 2, yes. Otherwise anti-platelet agents.
    

Consider the cause of the AF:

• Hypertension
• Structural Heart Disease
• Hyper/hypo thyroidism
• Alcohol/Stimulants
• Ischemia
• PE
• Infection
• Other stressor

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We have previously talked about septic bursitis and septic arthritis here.

I will expand on that by saying that one of the keys in effective management is source control. The septic joint should be repeatedly tapped until there is a negative culture and the cell count is dramatically decreased. If it isn't improving -- they will need surgical management. If you can't tap the joint, they will need surgical management. This is particularly a problem with "difficult" to aspirate joints like the shoulder or hip. These patients should have orthopedic surgery to wash out the joint.

Failure to drain the joint can lead to treatment failure and joint damage.

Here is a good review of the diagnosis and management of acute septic arthritis.

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1. For the record, ciprofloxacin monotherapy is a totally inappropriate empiric choice for the treatment of community acquired cellulitis (even if the patient is penicillin allergic)
   
   • Penicillin allergy is one of the bains of my existance. I direct you to this article on trying to determine if a history of penicillin allergy is "real".

Day #124 - Pretibial Septic Bursitis

Today's case was of a painter, who did a lot of work on his hands and knees, presenting with acute onset knee pain. We discussed the differential diagnosis in detail and then focused on septic arthritis. I have previously blogged about this here and had linked to an excellent article that I recommend you reading.

In this case, the diagnosis was pretibial septic bursitis, which can mimic septic arthritis and is commonly seen in people who do labor on their hands and knees and is associated with minor traumas. The most common infectious aetiology is stapylococcus aureus.

Day #93 - Staphylococcus Aureus Bacteremia

Today we talked about a patient who presented with a febrile gastrointestinal illness who happened to have two diagnoses. First, a probable viral gastroenteritis acquired from his daycare aged son. Second, a concomitant staphylococcus aureus bacteremia.

I wanted to talk about the management of Staphylococcus Aureus Bacteremia. There is a good article here on the management of MRSA bacteremia.

• Never treat staphylococcus aureus in the blood as a contaminant. Like fungus in the blood, this always needs to be treated!
• The *minimum* treatment duration is 14 days (intravenous). This is for uncomplicated infections only.
  
  • Risk factors for complication:
    
    • Longer duration of illness
    • Community acquired infection
    • Persistent fever at 72h (OR 2)
      
    • Persistent positive blood culture at 96h (OR 5)
      
    • Hemodialysis patients
    • Indwelling lines or other prosthetic material
    • MRSA
    • No identifiable source for the bacteremia (i.e. no skin or line focus)
    • Blood cultures positive within 14 hours of drawing them
      
• You need to exclude bacterial endocarditis. Present in 10-13% of cases...
  
  • TEE is much more sensitive than TTE for making this diagnosis (103 patients with SA -- TEE dx endocarditis in 25%, TTE only found 7%). In patients for whom you are planning 14d therapy (particularly those who have risk factors for complication) you should probably not rely on a TTE to exclude IE.
• Can also cause pacemaker and AICD infections
• Vertebral osteomyelitis
• Septic arthritis
• Splenic abscess (persistant fever, LUQ pain)
  
• Septic thrombophlebitis (particularly with lines)
• Septic pulmonary emboli
  
• Brain abscess/meningitis/mycotic aneurysms
• Skin/soft tissue abscesses

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Treatment:

• Ideal treatment for MSSA is with a beta-lactam like cloxacillin or cefazolin. These are superior head to head with vancomycin for the treatment of MSSA.
• Removable foci should be removed if feasible and practical to do so
• Duration depends on complications. IE 4-6 weeks. Osteo ~6 weeks.
  

Risk of Death

• 20 to 40%!
• Age
  
• MRSA (OR 9.3)
• Blood cultures positive less than 12 hours (OR 7)
• Complication (OR 9)
  

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In medicine we often attempt to find one unifying diagnosis that explains all symptoms -- in satisfying what is known as Occam's Razor.

The important teaching point in a complicated case like this is that the patient may have multiple diagnoses and that we must keep an open mind. In response to Occam's Razor, Hickam's Dictum states that "[the patient] can have as many diseases as the damn well please".

Day #56 - Acute Monoarthritis Redux

We again approached this issue today.

The differential diagnosis of subacute-acute monoarthritis includes:

• Septic arthritis (gonococcal, non-gonnococcal bacterial, tuberculosis, fungal)
• Crystal (gout, pseudogout AKA CPPD, hydroxyapatate)
• Osteoarthritis flare

More rarely an acute monoarthritis can be a presentation of

• Seropositive and seronegative arthridities including reactive arthritis and post-streptococcal arthritis
• Hemarthrosis (in hemophilia and acquired hemophilia)

We use the history and physical to help us form an opinion on the etiology, but ultimately because septic arthritis is so damaging if missed, a synovial fluid analysis is required if there is suspicion of septic arthritis.

A previous blog discussed septic arthtiris and synovial fluid analysis.

Day #4 - Acute Monoarthritis

Today the discussant spoke about the approach to acute monoarthritis. It was a very articulate presentation and your participation was excellent.

To clarify the point on treatment:

• CEFTRIAXONE 2g IV q24h will cover most organisms including GC, most streptococci, Staph. aureus and many gram negatives. It is not the ideal agent for Staph. aureus, so if it turns out to be methicillin *sensitive* staph. aureus you should change to ANCEF (1g IV q8) or CLOXAILLIN (2g IV q6)
  
• Is MRSA a possibility or is this a prosthetic joint? --> ADD VANCOMYCIN (renal dose)
• Is there reason to worry about pseudomonas? --> I would suggest VANCO+CEFTAZADIME and ID consult.
  

• Prosthetic Joint = Call ortho. Probably should not be admitted to medicine if septic prosthetic joint is the main reason they are in hospital -- they need to go to the OR for wash-out and, in my experience, this is much less likely if they are admitted to GIM instead of orthopedics. Should get ID consult as well.
  

This article from JAMA is an excellent reference on making an evidence based diagnosis of septic arthritis on history, physical and laboratory examination.

VIDEO: How to do an arthrocentesis of the knee

Highlights include:

Risk Factors: Age, DM, rheumatoid arthritis, joint surgery, hip/knee prosthesis, HIV infection, skin infection, (unprotected sexual intercourse for GC)

History: Pain and swelling are present >80% of the time; fever is present only 60% rigors and chills less than that.

Synovial Fluid Exam (LR less than 0.1 rules out; LR >10 rules it in)

• WBC <=25,000 unlikely septic arthritis (LR 0.32) unless immunosuppressed
• WBC >=25,000 LR 2.9
• WBC >=50,000 LR 7.7
• WBC >100,000 LR 28

• PMNs <90%>
• PMNs >90% LR 3.4
  

Important to note that measurement of glucose, protein, lactate do not appear to be helpful according to the literature. Also note that LDH in the joint may have some utility in ruling out as LDH <250>