Thursday, April 28, 2011

Diarrhea in HIV-infected patients

Diarrhea can cause significant morbidity in HIV-infected patients, and can be due to a myriad of causes from infectious pathogens, malignancy and even medications. Before the use of HAART, chronic diarrhea was a large cause of AIDS-defining conditions. However, in the current era the infectious causes of diarrhea in HIV-infected individuals in declining. Key to the evaluation of diarrhea in HIV-infected individuals is a thorough history that includes duration of symptoms, frequency and characteristics of stool, amount of weight loss, and the presence of other abdominal symptoms and constitutional symptoms. Additionally, all medications should be reviewed. A careful physical examination is key to help determine the degree of wasting or to identify any particular findings that may point to specific diseases. For example, fever and wasting may suggest an underlying opportunistic infection. Initial investigations should include stool examination and cultures, and blood cultures. Abdominal CT imaging and endoscopy may be considered if the initial non-invasive work-up is non-diagnostic.

Below is a list of several key causes of diarrhea in HIV-infected individuals:

Bacterial: salmonella, campylobacter, MAC, TB, C. difficile, shigella
Viral: CMV, herpes simplex, adenovirus, norwalk
Protozoal: microsporidium, cryptosporidium
Fungal: histoplasmosis, coccidiomycosis
Gut neoplasms: lymphoma, Kaposi’s sarcoma
Pancreatic insufficiency
Infectious pancreatitis: CMV, MAC
Drug-induced pancreatitis: didanosine, pentamidine
Tumor invasion: lymphoma, Kaposi’s sarcoma
Idiopathic: “AIDS enteropathy

Thursday, April 21, 2011

Is my patient delirious?

Delirium is a very common medical problem in elderly patients admitted to hospital. The 4 key features that characterize delirium include: (1) disturbance of consciousness with reduced ability to focus, sustain, or shift attention; (2) a change in cognition or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia; (3) the disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day; and (4) there is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by a medical condition, substance intoxication, or medication side effect.

The Confusion Assessment Method (CAM) is a simple tool that can be used by clinicians to integrate their observations and identify when delirium is the most probable diagnosis. In medical and surgical settings, the CAM has a sensitivity of 94-100% and a specificity of 90-95%.

Confusion assessment method (CAM) for the diagnosis of delirium

1. Acute onset and fluctuating course
- Usually obtained from a family member or nurse and shown by positive responses to the following questions: "Is there evidence of an acute change in mental status from the patient's baseline?"; "Did the abnormal behaviour fluctuate during the day, that is, tend to come and go, or increase and decrease in severity?"

2. Inattention
- Shown by a positive response to the following: "Did the patient have difficulty focusing attention, for example, being easily distractible or having difficulty keeping track of what was being said?"

3. Disorganized thinking
- Shown by a positive response to the following: "Was the patient's thinking disorganized or incoherent, such as rambling or irrelevant conversation, unclear or illogical flow of ideas, or unpredictable switching from subject to subject?"

4. Altered level of consciousness
- Shown by any answer other than "alert" to the following: "Overall, how would you rate this patient's level of consciousness?"
Normal = alert
Hyperalert = vigilant
Drowsy, easily aroused = lethargic
Difficult to arouse = stupor
Unarousable = coma

The diagnosis of delirium requires the presence of features 1 AND 2 plus either 3 OR 4.

Friday, April 15, 2011

Does my patient have COPD?

We are often faced with many patients who are given a label of obstructive airway disease based on a history of smoking and wheezing. But in many instances patients with these features do not have obstructive airway disease. Dr. Straus and colleagues identified 4 elements on history and physical examination that were significantly associated with a diagnosis of obstructive airway disease:

1. Smoking at least 40 pack-years (LR + 8.3)

2. Self-reported history of chronic obstructive airway disease (LR + 7.3)

3. Maximum larygeal height less than 4cm (LR + 2.8)

4. Age at least 45 yrs (LR + 1.3)

The presence of all 4 of these elements has a LR + 220, rulling in a diagnosis of obstructive airway disease.

Click on the following link to see the abstract: http://http//

Thursday, April 14, 2011

Adrenal Insufficiency

The clinical presentation of adrenal insufficiency is variable and depends on whether the onset is acute (leading to adrenal crisis) or chornic, with symptoms that are often vague and insidious. The key to making the diagnosis of adrenal insufficiency is a high level of clinical suspicion. The signs and symptoms of adrenal insufficiency depend upon the rate and extent of loss of adrenal function, whether mineralocorticoid production is preserved, and the degree of stress. The following is a list of key clinical features of primary adrenal insufficiency:

  • weakness

  • fatigue

  • anorexia

  • orthostatic hypotension

  • nausea

  • vomiting

The following is a list of key laboratory abnormalities of primary adrenal insufficiency:

  • hyponatremia

  • hyperkalemia

  • hypoglycemia

  • lymphocytosis

  • eosinophilia

  • hypercalcemia (rarely)

Tuesday, April 12, 2011

Patients with Headache

Headaches are a very common medical complaint. In assessing patients with headaches, we must determine who has a serious cause of a headache and who requires neuroimaging. A Rational Clinical Exam article from JAMA entitled "Does this patient with headache have a migraine or need neuroimaging?" helps to outline an approach to headache. After a systemic review of the literature, the best predictors of a migraine were summarized by the mnemonic POUNDing: Pulsation, duration of 4-72 hOurs, Unilateral, Nausea, Disabling). If a patient meets 4 out of the 5 criteria, the likelihood ratio (LR) for definite or possible migraines is 24. For neuroimaging, several clinical features were found on pooled analysis to predict the presence of a serious intracranial abnormality: cluster-type headache (LR 10.7), abnormal findings on neurological examination (LR 5.3), undefined headache (LR 3.8), headache with aura (LR 3.2), headache aggrevated by exertion or valsalva (LR 2.3), and headache with vomiting (LR 1.*). It should be noted that no clinical features were useful in ruling out significant pathologic conditions. To see the full Rational Clinical Exam article click here

Thursday, April 7, 2011

Dabigatran for anticoagulation in Afib

Dabigatran is an oral, direct thrombin inhibitor. Its efficacy and safety relative to warfarin was evaluated in the RE-LY trial, at 2 doses. It was the first randomized trial to demonstrate that an alternative oral anticoagulant is superior to adjusted-dose warfarin. Over 18,000 patients with non-valvular atrial fibrillation and at least 1 stroke risk factor were were randomly assigned to receive oral dabigatran at one of two doses (110 or 150 mg) twice daily, or adjusted dose warfarin (INR 2-3). The primary study outcome was stroke or systemic embolism. After a median follow-up 2 years, rates of the primary outcome were 1.69%/yr in the warfarin group, compared with 1.53%/yr in the group that received 110 mg of dabigatran (P<0.001), and 1.11%/yr in the group that received 150 mg of dabigatran (P<0.001). The rate of major bleeding was higher in the warfarin group, compared to the lower dose dabigatran group. This study concluded that in patients with atrial fibrillation, dabigatran given at a dose of 110 mg was associated with rates of stroke and systemic embolism that were similar to those associated with warfarin, as well as lower rates of major hemorrhage. To see the full article click here