Day #258 - Meningovascular Syphilis

Today we heard a case of a young man with headache and diplopia who rapidly went on to develop ischemic brain lesions and progressive deficits.

I have blogged about diplopia here.

The final diagnosis was meningovascular syphilis. The discussant also described the natural history (or stages) of syphilis as I have covered here.

Day #257 - Viral Encephalitis

Today we heard the story of a young woman with fever, headache, photophobia, and confusion/drowsiness with a normal CT and an LP with a lymphocytic pleocytosis with elevated protein. The presumed diagnosis was viral meningoencephalitis and she was treated with IV acyclovir.

Despite excellent data on bioavailability, there are only case reports of substituting oral valacyclovir for IV acyclovir in the treatment of HSV encephalitis. This would be an interesting option which would decrease the need for IV in patients who recovered after IV "induction". It is biologically plausible because the levels in the plasma achieved by valacyclovir approximate acyclovir without the concomittant nephrotoxicity. Apparently clinical trials are underway.

We have previously blogged about HSV encephalitis here.

Day #252 - Infective Endocarditis (Staphylococcus Aureus)

Today we heard a case of a patient with a known history of injection drug use who presented with multiple swollen joints, in the context of a persistant staphylococcal bacteremia. The patient also had a history of previous endocarditis and on exam had evidence of moderate-severe tricuspid regurgitation.

I have reviewed the diagnostic criteria for endocarditis here.

I have previously blogged about staphyloccocal bacteremia here. I will re-iterate that for methicillin sensitive staph aureus vancomycin is INFERIOR to beta-lactam therapy.

Some newer evidence suggests that the risk of using adjuvant gentamicin in native valve staphylococcal bacteremia/endocarditis is greater than the benefit.

An interesting concept, which I am now going to endorse because it is inexpensive and relatively simple, is continuous cloxacillin infusion as opposed to intermittant infusion. In this study the 30 day microbiologic cure was 94% in the CI group as opposed to 79% in the II group (ARR 15%, NNT 8).

There have been several studies looking at treatment options in injection drug users. Long term antibiotic therapy requires indwelling lines and this usually mandates extended hospitalization or "confinement" if ongoing drug use is a concern. These two studies (larger study, smaller study) have evaluated quinolone (ciprofloxacin, though today levofloxacin or moxifloxacin would likely be even more effective) combined with rifampin in right sided IE. These are small studies, so they shouldn't influence practice in general -- but in certain cases may be the only option.

Day #239 - Clostridium Difficile (C. Diff)

Today we discussed a case of severe Clostridium difficile associated diarrhea. I have previously blogged about the differential of colitis here.

There is a general review of C. difficile available from last week's JAMA. I prefer these two (#1 and #2) editorials by John Bartlett.

A full suppliment to the journal Clinical Infectious Diseases was devoted to C. difficile in January 2008 and it is very good.

Diagnosis of C. Diff

Microbiology

• At our hospital, the C. diff toxin assay (EIA) detects toxins A and B and has ~70% sensitivityon a single test, with ~90-95% sensitivity on three tests. The specificity greater than 95%.
• The most sensitive assay is the test for cytopathic effect, which is not available
• You can also culture Clostridium difficile from the stool, although most laboratories no longer do this, and just because you grow it does not necessarily mean that it is causing disease

CT Scan

• May show thickening of the bowel wall, colitis, ileus. "Double Halo" and "Accordian Signs"
  

Sigmoid/Colonoscopy

• May see pseudomembranes diagnostic of pseudomembranous colitis

Treatment of First Episode

• If possible stop offending antibiotics
• Mild/Moderate Disease
  
  • Metronidazole OR Vancomycin (PO) duration 10-14d
    
• Severe Disease
  
  • Defined as:
    
    • Two of (Age above 60, Febrile, WBC above 15, Albumin below 25)
      
    • OR hypotension/shock or Cr greater than 1.5x normal, or toxic megacolon, peritoneal signs, perforated bowel
      
  • Infectious Disease +/- General Surgery Consultation
  • ICU Consult for patients with hemodynamic comprimise
    
  • Vancomycin (PO) unless severe illeus, then Metronidazole (IV) duration 10-14d
    

Relapse

• First relapse --> can repeat last treatment depending on severity
• Second relapse --> vancomycin taper (see JAMA article). ID consult.
  

Day #237 - Hepatoma and HCC

Hepatocellular carcinoma is a highly vascular primary cancer of the liver which often arises in the context of underlying cirrhosis and ongoing/chronic liver inflammation caused by viral hepatitis (B and C). In general the risk in cirrhosis is approximately 3% per year.



The diagnosis is often made based on the radiographic appearance and clinical context. From uptodate: "If the lesion is hypervascular, has increased T2 signal intensity, demonstrates venous invasion, or is associated with an elevated AFP, the diagnosis is almost certainly HCC."

There are several staging systems. One useful system is the CLIP score:

• Underlying liver disease:
  
  • Child-Pugh A = 0, B=1, C=2
• Size and extent of tumour
  
  • Uninodular and not extending more than 50% =0
  • Multinodular and not extending more than 50% =1
  • Massive or extending more than 50% = 2
• AFP greater than 400 = 1
• Portal vein thrombus =1

CLIP: 0, 1, 2, 3, 4, 5/6 has associated median survival of 31, 27, 13, 8, and 2 months respectively.

There can be several paraneoplastic syndromes associated with HCC:

• polycythemia (related to EPO)
• hypercalcemia
• hypoglycemia
• chronic watery diarrhea
  

Treatment:

• In general surgical resection is limited to patients with good hepatic reserve (CPA), absence of metastases, absence of invasion of major vascular studies.
  
• Surgery is generally more successful in lesions less than 5cm
• Transplantation of the liver can be an option in patients with inadequate reserve or otherwise unresectable lesions. This really is only an option for lesions less than 3-5cm and solitary or less than three lesions.

• Radiofrequency ablation (RFA) is an option for lesions less than 4-5 centimeters who are otherwise deemed unresectable.
• TACE (transarterial chemoembolization) is an option for unresectable lesions in the absence of portal vein thrombosis. It is relatively contraindicated in tumours making up more than 50% of the liver, heart failure, renal failure, ascites, GI bleeding or thrombocytopenia.
  

There was a recent publication on the use of tyrosine kinase inhibitors in the treatment of advanced HCC showing improved survival.

I have previously blogged about hepatitis B, the most common worldwide cause of hepatoma, here.

Day #236 - Pneumocystis (PCP) x 3

I've previously blogged about PCP here.

We discussed opportunistic infections in HIV here.

A previous talk I've given on HIV is available here.