Tuesday, July 19, 2011
Findings and clinical mimics of common limb-lead changes:
Right arm-Left arm:
- Q wave I, aVL
- Inverted p-wave I, II, II, aVF
- Mimics: old lateral infarct, non-sinus atrial activity, dextrocardia (limb lead reversal will still have normal R-wave progression, dextrocardia will not)
Right arm- Left leg:
- Q wave II, III, aVF
- Inverted p-wave II, III, aVF
- Mimics: old inferior infarct, non-sinus atrial activity
Right arm- Right leg:
- Diffuse low voltage in limb leads (esp. lead II)
- Mimics: any condition causing low voltage (limb-lead reversal will have normal precordial voltages)
Other limb lead reversals causing only minor changes with no real clinical mimics include Left arm- Left leg, Left arm- Right leg and leg-leg reversals. Precordial lead changes will interfere mostly with R-wave progression.
More from an old but concise review here.
Monday, July 18, 2011
Friday, July 15, 2011
A few points on mesothelioma, with more in NEJM here:
–Malignancy of pleura (<90%) or peritoneum (>10%)
–~90% of patients will have a history of exposure to asbestos, with mean time from exposure to diagnosis ~35y (wide range)
Thursday, July 14, 2011
- Upper-GI tumors: Fundic gland polyps, duodenal adenomas
- Adenocarcinoma of the ampula of Vater
- Extra-intestinal features: osteomas, desmoid/soft-tissue tumors, retinal pigment hypertrophy
Here is a link to a basic BMJ review on hereditary colorectal cancer.
Wednesday, July 13, 2011
A quick review of the associated dermatologic findings:
Gottron’s papules-80% of patients
Heliotrope rash- <50% of patients
We didn't get in to the management of hyperkalemia, but as Dr. Bunce said- you should know it by tomorrow, so here is a prior post with a good link to a review at the bottom.
Tuesday, July 12, 2011
Pendred's syndrome is an autosomal-recessive disorder of iodine organification caused by mutations in iodine transport protein pendrin.
It is characterized by the combination of congenital sensorineural hearing and goiter, and accounts for up to 10% of cases of hereditary deafness.
Patients have a positive perchlorate discharge test because they cannot provide substrate for the organification step in thyroid hormone synthesis.
Monday, July 11, 2011
Thursday, July 7, 2011
The other discussion was on stem cell transplants and graft versus host disease (GVHD). A few points:
1) Types of stem cell transplant:
Autologous: Patient's own mononuclear cells are harvested from bone marrow or (now more commonly) from peripheral blood prior to high-dose myeloablative chemotherapy/radiotherapy. The cells are then reinfused during the period of prolonged bone marrow failure that occurs after these treatments in order to help restore hematopoiesis. Classically this type of transplant was used in lymphoma, but there is an ever-expanding list of trials for other indications including solid tumors and plasma-cell dyscrasias.
Allogeneic: Stem cells are harvested from the bone marrow of healthy donors or newborn umbilical cord/placenta. The cells are infused to reconstitute the patient's hematopoeitic system, but also can have direct anti-leukemia activity, termed graft-versus-leukemia (GVL). Given that the cells are from a donor, there are a greater number of risks than in autologous transplant due to immune suppression and graft-versus-host-disease (below).
2) Graft versus host disease:
Lymphocytes from the donor may target normal host tissues and cause inflammation, with particular predilection for skin, gut, liver, and lungs. The acute form usually occurs before 100 days post-transplant and can present with a maculopapular or bullous rash, cholestasis potentially leading to hepatic failure, or secretory diarrhea. The chronic form more resembles other autoimmune disorders, presenting with arthritis, scleroderma-like skin changes, sicca syndrome, chronic hepatitis, and GI malabsorbtion.
The risk of GVHD is directly related to age and inversely related to the the degree of major histocompatibility antigen matching between donor and recipient. It remains the major complication of allogeneic transplant, affecting upwards of 40% of patients.
Wednesday, July 6, 2011
Here is a prior post on the causes of pericarditis
When thinking of pericardial effusions, the causes are all the same, as well as the addition of hypothyroidism.
We talked only briefly about cardiac tamponade, but here is a link to the JAMA rational clinical exam paper 'Does this patient have cardiac tamponade'
I will be using the blog quite a bit this year, but I plan to use it a little differently than before in a few ways: