Day #292 - Meningoencephalitis

Today we discussed a few issues:

1. The developing influenza outbreak (see previous blogs on influenza). A review of the neurologic manifestations of influenza infection is available here.
   
2. A case of meningoencephalitis (see TWH blog), presumably due to mumps (though I have my reservations as the parotid enlargement classically predates the encephalitis and the IgM is still pending!)
3. TB Meningitis was discussed given the epidemiology.
   

Day #288 - Fulminant Hepatitis from Hepatitis B

Today we discussed a case of a patient with chronic hepatitis B who presented with massive elevations of his liver enzymes. The cause was felt to be a flare of his underlying hepatitis B.

Day #287 - Massive Splenomegaly

Today we heard about a patient with massive splenomegaly who presented with symptoms anorexia and weight loss.

We discussed the physical diagnosis of splenomegaly. We also talked about differentiating the spleen from an enlarged kidney or stomach based.

Spleen

• Has notch
• Cannot palpate above
• Descends with inspiration
• Cannot ballot
• Splenic rub

Kidney

• No notch
• Can ballot
• May be able to palpate above
• No change with inspiration

Stomach

• No notch
• Cannot ballot
• Can not palpate above
  
• Succession splash
  

We then discussed the differential diagnosis for massive splenomegaly (8cm below costal margin or greater than 1kg) which includes:

• CML, CLL, Hairy Cell Leukemia, and other lymphomas
• Myelofibrosis (less commonly PRV)
• Gaucher's disease (or rarely sarcoidosis)
• Autoimmune Haemolytic Anemia
• Kala-Azar

Remember, the spleen can be enlarged by three mechanisms:

1. Hypertrophy or hyperplasia related to increased splenic function (i.e. thalasemia, infection, autoimmune disease)
2. Congestion due to portal hypertension
3. Infiltration (i.e. lymphomas, leukemias, extramedulary haematopoesis, amyloid)

We finally ended up talking about making the diagnosis in this case, which is likely lymphoma.

Day #278 - Cavitary Lung Lesion

Today we heard the case of a young man with a history of constitutional symptoms (sweats, weight loss) in association with a non-productive cough and a cavitary right upper lobe infiltrate.

I have previously blogged about the differential of cavitary lung lesions

Based on the presentation I favor an infectious etiology, most likely tuberculosis. The absence of AFB on the bronchoscopy does *not* mean this isn't tuberculosis.

This study of 230 cases of culture positive pulmonary tuberculosis showed that the BAL AFB stain was only positive in 48/95 patients without spontaneous sputum production. In this study, the sensitivity of BAL AFB stain was better, but still only 70%.

The take home message is that a negative smear does not exclude TB in a compatible case. Repeat samples are sometimes indicated and awaiting the final culture is also required. In this case I would add induced sputum daily in the AM for three days to maximize my chances of making the diagnosis.

This article reviews the various radiographic manifestations of pulmonary tuberculosis.

Treatment of Pulmonary TB (see Canadian Tuberculosis Standards):
Initial:

• Isoniazid (INH) +/- Vitamin B6
  
• Rifampin (RIF)
  
• Pyrazinamide (PZA)
  
• Ethambutol (ETH)
  

If demonstrated susceptible to INH/RIF/PZA:

• Can stop ETH immediately
  
• Continue INH/RIF/PZA until 2 months then stop PZA
• Continue INF/RIF 4 months to complete 6 total months
  

Day #266 - Febrile Neutropenia

Today we discussed a case of a patient with multiple immunological deficiencies (a review of primary immunodeficiencies is available here)

Multiple myeloma with dysgammaglobulinemia predisposing to infections with encapsulated organisms like streptococcus pneumoniae and other bacterial infections like staphylococci.

High dose prednisone leading to relative deficiencies with cell mediated immunity predisposing to intracellular organisms (i.e. salmonella, listeria), mycobacterial, and fungal infections.

TNF alpha antagonist leading to further risk of fungal and mycobacterial infections

And drug induced febrile neutropenia predisposing to infection with bacteria including pseudomonas as well as fungi such as candida species, aspergillus, and other moulds.

The 2002 (under revision) IDSA guidelines for the management of febrile neutropenia are available here.

When initially seeing the febrile neutropenic patient, the goals (in general) are to:

1. Stablize and rescucitate as appropriate
2. Identify any specific focus of infection on history and physical exam
   
   • Pay attention in particular to sinuses and dental sources, mucositis, new murmurs, skin foci including central line sites and tunnels, evidence of pneumonia, evidence of intrabdominal focus, peri-rectal exam (no DRE)
   • CXR for all cases. Sinus, CT thorax, abdominal, other imaging as clinically indicated.
     
3. Obtain cultures from all sites including two sets of blood cultures and cultures from any indwelling intravenous lines.
   
4. Initiate broad spectrum antibiotic therapy to cover for usual pathogens implicated in febrile neutropenia adjusting/broadening to include identifiable focus
   
   • In general an antipseudomonal beta-lactam combined with an aminoglycoside is a standard regimen with the addition of VANCOMYCIN in patients with indwelling intravenous catheters, risk for MRSA, or who come in pre-treated with quinolone prophylaxis
5. Tailor antibiotics to culture results but remain broad-spectrum while neutropenic
   
   • i.e. if no gram positive identified can consider stopping VANCOMYCIN at 72h
     
   • if no pseudomonas or gram negative identified at 72h can consider stopping aminoglycoside and continuing the beta-lactam