Thursday, November 17, 2011
We also discussed about the management of spontaneous bacterial peritonitis. See a nice review of cirrhosis and ascites in NEJM here.
Monday, November 14, 2011
Monday, September 19, 2011
Friday, September 16, 2011
- Recent trend in cocaine being adulterated by levamisole,
- An anti-helminth agent in the 1960s first identified as a cocaine adulterant in the USA in 2003
- Now found in majority of cocaine seized at US borders, common in Canada also
- Proposed that levamisole potentiates the psychotropic effects of cocaine, and that producers intentionally add it during the cocaine manufacturing process
- Associated with a cutaneous vasculitic syndrome
- Purpuric lesions and/or cutaneous necrosis
- Involves the ears in ~50% of reported cases
- Lab associations: neutropenia + pANCA and + cANCA
1) Acute seroconversion reactions:
-Although rare, acute neurologic presentations at the time of HIV infection do occur, including aseptic meningitis, Bell's palsy, and inflammatory neuropathies. CSF testing for HIV may be positive in these patients.
2) Opportunistic infections: A variety of OI can manifest with neurologic presentations:
- Progressive Multifocal Leukoencephalopathy (PML): a demylenating CNS disease caused by JC virus, mostly in patients with CD4 counts less than 100. Usual presentation is a subacute deterioration in mental status with possible focal neurologic signs/symptoms, with fever and headache not usually present.
- Cytomegalovirus (CMV): although 60% of the population have evidence of exposure to CMV, patients with HIV and CD4 counts less than 50 and other immunocompromised states are at risk of clinical disease from reactivation. CMV can infect and reactivate throughout almost the entire spectrum of the CNS and PNS- from the brain to peripheral nerves. For this reason, the neurologic presentation can be any combination of encephalitis, ventriculitis, myelitis, gangionitis and peripheral polyneuropathy.
- Cryptococcus neoformans: an encapsulated yeast found throughout the world. It usually is cleared by the immune system, but in immunocompromised patients, including HIV patients with CD4 counts less than 100, it can remain in a latent state that can disseminate to organs, with the CNS being particularly common. The usual presentation is that of a subacute menigoencephalitis, with fever, headache and malaise. It can also present with complications of increased ICP, including seizure.
- Toxoplasma gondii: intracellular protazoan with high seroprevalence in the population, with most primary infections being asymptomatic or flu-like. Reactivation can occur in immuno compromised hosts, usually in patients with HIV and CD4 counts less than 200. Usually casues an encephalitis and presents with fever, headache, and focal neurologic signs or seizures.
3) Neoplasms: primary CNS lymphoma is usually a high grade B-cell lymphoma and almost always related to Epsetin -Barr Virus (EBV). It usually presents in HIV patients with CD4 counts less than 100 with headache, changed mental status, focal neurologic signs or seizures.
4) Immune reconstitution inflammatory syndromes (IRIS): a group of syndromes casued by the inflammation generated by a reconstituted immune system in the first 4-8 weeks after starting on combined antiretroviral therapy. Usually seen in HIV patients with CD4 counts less than 50 being started on therapy for the first time in the setting of an opportunistic infection. Typically presents as a paradoxical worsening of course in patients with HIV encephalitis, cryptococcal meningitis toxoplamsamosis encephalitis and PML.
5) HIV associated peripheral neuropathies: many peripheral neuropathic syndromes have been reported in the context of HIV infection, with the most common being a distal peripheral sensory neuropathy. Modifiable risk factors include use of neurotoxic medications, diabetes and alcohol abuse.
6) HIV-associated vacuolar myelopathy: an entity of unclear pathophysiology affecting the spinal cord neurons, more often the dorsal column. It presents with often initial errectile dysfunction and hyper-refexia, but progresses to asymmetric spastic leg weakness, dorsal column vibration/position sensory loss, and ataxic gait.
7) HIV Associated neurocognitive disorders (HAND): this is a group of neurocognitive changes thought to be a spectrum of a subcortical process that primarily affects attention/concentration, psychomotor speed, memory/learning, information processing, and executive function, while language and visuospatial abilities are often relatively unaffected.
More on diagnosis of these conditions from a review article here.
Tuesday, September 13, 2011
Friday, September 9, 2011
- Pendred's syndrome here
- Dermatologic findings in dermatomyositis here
- Familial Adenomatous Polyposis here
- Limb lead reversal here
Thursday, September 8, 2011
A prior post on hyperkalemia here, with a link at the bottom to a recent CMAJ article on management.
A prior post on renal tubular acidosis here, with a good review from the Archives here.
Thursday, September 1, 2011
A little more about medullary thyroid cancer (MTC):
- MTC can be either sporadic or inherited. Inherited forms involve mutations to the RET proto-oncogene and can be either be alone or as part of one of the Multiple Endocrine Neoplasia syndromes- MEN 2A or MEN 2B.
- MEN 2A is characterized by MTC with hyperparathyroidism and/or pheochromocytoma
- MEN 2B is characterized by MTC with typical phenotyic features such as marfanoid body habitus or mucosal neuromas with or without pheochromocytoma.
- Most patients present with a thyroid mass, but some present with symptoms of local spread such as dysphagia, dyspnea, or hoarseness. Roughly 10% will present with systemic symptoms related to the production of neuroendocrine mediators such as calcitonin, resulting in bone pain, flushing, and/or diarrhea.
- Those that present with systemic symptoms usually have metastatic disease.
- More in a review from Cancer here
We also found out through our group searching excercise that MTC is associated with secondary amyloidosis casued by calcitonin.
-A good related article sent out by Dr. Abrams here.
- More on amyloidosis from a prior post here.
Wednesday, August 10, 2011
•It is also known as :Stress-induced cardiomyopathy, apical ballooning syndrome, or broken heart syndrome
•Characterize d by transient systolic dysfunction of the apical and/or mid segments of the left ventricle
–mimics myocardial infarction with ST segment changes
–absence of obstructive coronary artery disease
•Typically presets w. RSCP, but occassionaly with new onset dyspnea
–Women >> Men
–Often at time of intense physical or emiotional stress
•Pathogenesis not well understood
–? Catecholamine surge
See a nice brief article in CMAJ here.
Cardiac tamponade is a clinical syndrome with a few defining characteristics:
-hemodynamic instability (hypotension, tachycardia)
-pulsus paradoxus >10 mmHg
-jugular venous distention
- reduced heart sounds
The primary physiologic abnormality is compression of all cardiac chambers as a result of increasing intrapericardial pressure, which is mostly determined by the rapidity of fluid accumulation, rather than the absolute size of an effusion.
The diagnostic modality of choice is doppler echocardiography. In the presence of an effusion, some echocardiographic signs of tamponade:
- Early diastolic collapse of the right ventricle
- Late diastolic collapse of the right atrial free wall
- Less specific than RV collapse unless lasting for >30% of cardiac cycle
-Left atrial collapse
- Only in 25% of cases, but is highly specific
-Accentuated respiratory variation in peak mitral and tricuspid inflow velocities
-Reduction/absence of the normal decrease in inferior vena cava diameter during inspiration
See here for a good NEJM review
See here for the JAMA acticle "Does This Patient With a Pericardial Effusion Have Cardiac Tamponade?"
Tuesday, August 9, 2011
Auricular cartilage calcification and even true ossification of the auricular cartilages have been described in association with:
–mechanical tissue injury
–exposure to cold
–endocrinopathies including adrenal isufficiency
See more from NEJM here.
Monday, August 8, 2011
The classic digitalis effect has 4 typical findings on ECG:
- Virtually any: flattening, inversion, other abnormal waveforms such as peaking of the terminal portion (seen in about 10% of patients)
3.Sagging or “scooped” ST-segment with concomitant ST-segment depression
- More pronounced in leads with tall R waves (e.g. lateral leads)
4.Increase in the U-wave amplitude
It is important to remember that these do not correlate with toxicity as they can be seen at levels well within normal therapeutic range.
For a good review on this and the other important arrythmias assiociated with digoxin toxixicy, see here.
Thursday, August 4, 2011
–Autosomal dominant inheritance
–New mutations primarily in paternal chromosomes
–Complete penetrance but variable expression
•At least 2 of the following features needed to make the diagnosis:
–6 or more café-au-lait macules
–2 or more neurofibromas of any type or one plexiform neurofibroma
–Freckling in the axillary or inguinal regions
–2 or more Lisch nodules (iris hamartomas)
–A distinctive bony lesion such as sphenoid dysplasia or thinning of the long bone cortex
Wednesday, August 3, 2011
A prior post on differentiating the central and peripheral casues of vertigo here. See the bootom for more info on the Eply manuvers.
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: