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 #230 - Eosinophillia and Pulmonary Infiltrates

Today we heard a case of a patient with 2 weeks of fever and cough with diffuse abnormal chest x-ray infiltrates and profound eosinophilia.

This differential diagnosis of pulmonary eosinophilia is discussed here. Another good review is available here.

Interestingly -- there are case reports of SSRI induced eosinophilic pneumonia and our patient in this case was on two different SSRIs.

Update Oct 2010
This local publication deserves mention -- Tropical Pulmonary Eosinophilia from Toronto General's Tropical Disease Unit.

Day #229 - Strep Throat plus or minus HSV Encephalitis

We heard a case today for which the diagnosis was unclear. The patient presented with a febrile illness with odynophagia and headache accompanied by hallucination which was ascribed to group A streptococcus.

A review of the neurologic sequelae of GAS infection is available here. There has been a link between GAS infections and neuropsychiatric symptoms (primarily OCD and tic disorders) in children.

He was also treated for HSV encephalitis because of fever, headache, and the development of seizures. This was despite an initially negative HSV PCR. Many experts will continue treatment and repeat the LP in 3-7 days in patients in whom they have a high index of suspicion. This would be such a case. The ID Society of America has guidelines on the management of viral encephalitis available here. This article outlines the risk factors for severe disease and poor outcome in HSV encephalitis.

Day #228 - Bilateral Optic Neuritis

Today we heard a great case of bilateral visual loss that was ultimately diagnosed as bilateral optic neuritis.

Acute demylenating optic neuritis typically presents with progressive unilateral eye pain (usually with movement) and visual loss over hours to one week. The visual loss may be exacerbated in the shower (Uhtoff's phenomenon). Progressive worsening over more than one week is atypical as is failure to improve within 4 weeks.

Patients will present with visual acuity loss (mild to severe), abnormal visual fields (typically central scotoma), decreased colour vision, and a relative afferent papillary defect. There may be papilitis of the optic nerve, but it may also appear normal in retrobulbar optic neuritis.

MRI brain can be helpful -- will typically show enhancement of the optic nerves with gadolinium. The presence/absence of other lesions typical of multiple sclerosis (periventricular horizontal projections AKA Dawson's fingers) corresponds to a 10 year risk of developing MS of ~55% and 25% respectively.

LP to look for oligoclonal banding is of use in patients whose MRI is not typical for MS to predict the risk of developing MS but the data set is small. Essentially all of the few patients in the optic neuritis treatment trial (ONTT) with a normal MRI and oligoclonal banding on LP went on to develop MS.

Intravenous methylprednisolone (250mg IV QID x 3days then prednisone 1mg/kg x 11 days) can improve the time to return of vision; however, there are no differences in visual acuity at 1 year. There may be a reduced risk of MS over 2 years, but it does not persist beyond that and this benefit is primarily for those with MRIs with typical MS abnormalities. It seems that oral prednisone was worse than placebo in terms of ON recurrance and consequently most people will avoid oral steroid monotherapy.

There is a good NEJM review here. There is another good review here.

There is a related disease to MS known as Devic's disease which involves the optic nerves and spinal cord and often spares the brain. A review of this condition is here.

While optic neuritis is a rare ophthamologic presentation of syphilis, the condition itself is treatable and a convincing history of primary syphilis is often absence. Consequently in any patient with "MS" or optic neuritis, syphilis should probably be excluded. There is debate over this statement.

B12 deficiency can also present with demyelenating lesions and bilateral optic neuropathy and, although rare, should be considered.

This is a whole journal issue (Seminars in Ophthomology) devoted to optic neuropathy and there are articles on ADON, infectious optic neuropathy, toxic optic neuropathy, and others.

Day # 217 - Polymyalgia Rheumatica

Today's case was highly suspicious of PMR with an elderly woman presenting with bilateral shoulder and hip girdle stiffness with associated proximal muscle weakness and pain. It was not suggestive of closely related Giant Cell Arteritis as there was no suggestion whatsoever of temporal arteritis.

Polymyalgia rheumatica is reviewed in NEJM here.

Day #216 - Acute Interstitial Nephritis

We talked about a case of a patient with an acute rise in creatinine to the 600's from a baseline of 50 in the context of adding new medications. The patient developed eosinophilia and white blood cell casts compatible with a diagnosis of interstitial nephritis.

The types of interstitial nephritis are shown (above).

A similar case is presented in the NEJM here with associated discussion. This was also a case of presumed drug induced AIN. Some of the more common causes are listed (above)

A more detailed review on drug induced AIN is available here.

The role of urine eosinophils (i.e. maybe there shouldn't be a role) in this diagnosis is reviewed here.

I've previously blogged about renal failure (and linked to good articles) here.

Day #215 - Pancytopenia from Lymphoma

Classification of Lymphoma:

A good review article here, from which I have shared with you some of the best figures. If you read this you realize that the classification of lymphoma is extremely complicated and depends on morphologic appearance, genetics and immunophenotype. Lymphomas can arise from B-cells, T-cells or Natural Killer (NK) cells.

It is far easier to conceptualize non-Hodgkin's lymphoma as follows:

Indolent (survival in years, difficult to treat ~ 1/3 of all new diagnoses):

• Follicular lymphoma, Small Lymphocytic Lymphoma (like CLL but primarily nodal disease), Mantle Cell Lymphoma, Marginal Zone Lymphoma

Agressive (survival in months, curable)

• Diffuse Large B Cell Lymphoma (DLBCL), Anaplastic T Cell Lymphoma, Peripheral T Cell Lymphoma

Super Aggressive (survival in weeks, potentially curable)

• Burkitt's Lymphoma, B Cell Lymphoblastic Leukemia, Adult T Cell Leukemia/Lymphoma, T cell lymphoblastic leukemia

We reviewed the Ann Arbor Staging System:

• Stage I - 1 chain
• Stage II - 2 separate chains, same side of diaphragm
• Stage III - Disease on both sides of diaphragm
• Stage IV - Diffuse involvement of extralymphatic organ (i.e. liver, lung, bone marrow, brain)

There are suffixes appendied to this based on:

• B - B symptoms: fever, Night sweats, 10% weight loss
• S - If spleen is involved

Staging is performed by CT scans of thorax/abdomen/pelvis to document nodal disease.

A bone marrow biopsy can be performed to look for involvement.

Lumbar puncture is indicated in:

• Patients with neurological symptoms
• HIV associated lymphoma
• Patients with bone marrow involvement (and aggressive lymphoma)
  
• Highly aggressive lymphoma
• Patients with 2 extranodal sites
  

Prognosis in NHL depends on tumor subtype. For the Aggressive Lymphomas the International Prognostic Index can be used. Bad prognostic features include

• Age >60
• ECOG greater than 2
• LDH abnormal
• Stage III or IV disease
• More than 1 extranodal site of disease
  

Score/5yr Survival (WITH TREATMENT)

• 0-1: Low Risk ~ 75%
• 2: Intermediate Risk ~50%
• 3: Intermediate Risk ~40%
• 4-5: High Risk ~25%
  

Reiterating the point about excisional biopsy this 2008 publication highlights the very important role of the general surgeon in making the diagnosis! Supraclavicular, axillary or cervical nodes are much higher yield than inguinal nodes.

NB: HIV, Hepatitis B, and Hepatitis C testing should be performed in new diagnoses -- particularly in younger patients.

Day #214 Diplopia

The discussant went over an approach to diplopia:

• Neurological -- i.e. ischemia/vasculitis, demyelination, tumour (including leptomenegeal), infection (TB, syphilis, listeria, lyme), toxic/metabolic (alcohol/wernike's)
  
• NMJ - mysesthenia and other myesthenic syndromes
  
• Muscular/Structural - Graves, masses in the muscles, muscular impingement
  
• Opthomologic -- monocular diplopia -- think corneal or lens problem

The physical exam can be helpful in determining which cranial nerve is involved. This site is actually quite informative with regards to the innervation of the cranial nerves and the section on gaze is good to read. This site has some interactive eye movements examples.

Cranial Nerve III:

• Pupil spared/Involved
• Adducts the eye/Innervates Medial Rectus
• Typically "down and out" gaze on affected side with inability to adduct

Cranial Nerve IV:

• Inability to look down and in leading to diplopia while walking down stairs or reading newspaper
• Head characteristically tilted away from the lesion

Cranial Nerve VI:

• Inability to abduct the eye
• Eye deviated inwards
  

Intranuclear Opthalmoplegia:

• Typically normal gaze when looking straight ahead
• Inability to abduct the eye on the contralateral side of the lesion due to failure of co-ordination of gaze.
  

Day #210 Complex Case - Gaucher's Disease

A very complicated case today where we touched upon multiple issues.

Here is a good case review of more than 1000 patients with Gaucher's disease.

Here is a case review of malignancies in Gaucher's disease.

• Bottom line: The risk of lymphoma, melanoma, and pancreatic cancer is 2-3 fold that of age matched healthy controls.

Day #209 - Intestinal Ischemia

Today we heard an interesting case of a patient with post-prandial pain, early satiety and weight loss. The underlying cause was obstruction of the celiac and superior mesenteric arteries.

There is a general review of SMA syndrome here.

The relevant anatomy is reviewed below (images from wikimedia.org, click to enlarge)

Celiac Artery:
Superior Mesenteric Artery:Inferior Mesenteric Artery:

Day #208 - Cryptococcal Meningitis

We resurrected an old case today. I've previously blogged about cyrptococcal meningitis here and here. There are useful links to the HIV guidelines on those pages.

Here is a link to a talk I once gave on "the basics" of HIV.

Day # 207 - Obstructive Renal Failure in Pregnancy

We had a good discussion today looking at the approach to renal failure (previous blog here) in pregnancy.

It is important to note that the correlation between flank pain in pregnancy and hydronephrosis is tenuous. In cases of obstruction, MRI can be useful in differentiating between physiologic and calculi obstruction with no radiation risk. In the absence of recurring infection, renal failure, intractable pain, these patients can be managed expectantly (reference).

Our patient had renal failure. The cause in this case (as evidenced by the rapid reversal after insertion of bilateral nephrostomy tubes) was obstructive, possibly related to the presence of large fibroids. A similar case has been published here. A review article on obstructive uropathy in pregnancy is here.