Diagnosis of chronic kidney disease: When to refer to a nephrologist?

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This is another recent review from Am Fam Physician:

Chronic kidney disease (CKD) affects 27 million adults in the U.S. It increases risk of cardiovascular disease and stroke.

Patients should be assessed annually to determine whether they are at increased risk of developing chronic kidney disease (CKD).

Risk factors for CKD include:

- diabetes mellitus
- hypertension
- older age
- cardiovascular disease
- family history of chronic kidney disease
- ethnic and racial minority status

Tests for CKD:

- Serum creatinine levels can be used to estimate the glomerular filtration rate (GFR)
- Spot urine testing can detect proteinuria

Staging of CKD is based on estimated glomerular filtration rate (GFR). Evaluation should focus on the specific type of CKD and identifying complications related to the disease stage.

When to refer to a nephrologist?

The patients with the following characteristics should be referred to a nephrologist:

- estimated glomerular filtration rates less than 30 mL per minute per 1.73 m2
- significant proteinuria
- rapid loss of kidney function

References:

Chronic Kidney Disease: Detection and Evaluation. Baumgarten M, Gehr T. Am Fam Physician. 2011 Nov 15;84(10):1138-1148.
Nephrology Cases

First snowmobile front flip landed and winter sport trauma (video)

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Heath Frisby lands the first snowmobile front flip in competition:



This is what happens when the things don't go as planned: Colten Moore flies 120 feet into the air and then hits the snow hard in Snowmobile Freestyle Finals... (video below). He not only survived but went on to win Winter X Games Gold later.



Not all extreme winter sport champions are so lucky though, and some of them have barely escaped death, with life-altering injuries: Kevin Pearce reflects on Sarah Burke's death (USA Today).

Chronic Diarrhea - Diagnostic Evaluation

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Chronic diarrhea is defined as a decrease in stool consistency (loose BM) for more than 4 weeks (Am Fam Physician, 2011).

It can be divided into 3 categories:

- watery
- fatty (malabsorption)
- inflammatory

Watery diarrhea

Watery diarrhea may be subdivided into:

- osmotic
- secretory
- functional, e.g. IBS

Watery diarrhea includes irritable bowel syndrome (IBS), which is the most common cause of functional diarrhea. Another example of watery diarrhea is microscopic colitis, which is a secretory diarrhea affecting older persons.

Laxative-induced diarrhea is often osmotic.

Malabsorptive diarrhea

Malabsorptive diarrhea is characterized by excess gas, steatorrhea, or weight loss. Giardiasis is a classic infectious example of malabsorptive diarrhea.

Celiac disease (gluten-sensitive enteropathy) is also malabsorptive, and typically results in weight loss and iron deficiency anemia.

Inflammatory diarrhea

Inflammatory diarrhea, such as ulcerative colitis (UC) or Crohn disease, is characterized by blood and pus in the stool and an elevated fecal calprotectin level.

Invasive bacteria and parasites also produce inflammation. Infections caused by Clostridium difficile (C. diff.) subsequent to antibiotic use have become increasingly common and virulent.


Image source: Escherichia coli, Wikipedia, public domain.

Not all chronic diarrhea is strictly watery, malabsorptive, or inflammatory, because some categories overlap.

References:

Evaluation of Chronic Diarrhea. Juckett G, Trivedi R. Am Fam Physician. 2011 Nov 15;84(10):1119-1126.
Skin patch vaccine to prevent travelers' diarrhea
Image source: Colon (anatomy), Wikipedia, public domain.

How to evaluate a patient with chronic cough?

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Initial evaluation of chronic cough (defined as more than 8 weeks' duration in adults and 4 weeks in children) should include a chest radiography (CXR) in most adult patients.

Patients who are taking an angiotensin-converting enzyme inhibitor (ACEi) should switch to a medication from another drug class.



Differential diagnosis of cough, a simple mnemonic is GREAT BAD CAT TOM. Click here to enlarge the image: (GERD (reflux), Laryngopharyngeal Reflux (LPR), Rhinitis (both allergic and non-allergic) with post-nasal drip (upper airway cough syndrome), Embolism, e.g. PE in adults, Asthma, TB (tuberculosis), Bronchitis, pneumonia, pertussis, Aspiration, e.g foreign body in children, Drugs, e.g. ACE inhibitor, CF in children, Cardiogenic, e.g. mitral stenosis in adults, Achalasia in adults, Thyroid enlargement, e.g. goiter, "Thoughts" (psychogenic), Other causes, Malignancy, e.g. lung cancer in adults).

The most common causes of chronic cough in adults are:

- upper airway cough syndrome (post-nasal drip)
- asthma
- gastroesophageal reflux disease (GERD)
- any combination of the above

If upper airway cough syndrome is suspected, a trial of a decongestant and an antihistamine is warranted.

The diagnosis of asthma can be confirmed with a clinical response to empiric therapy with inhaled bronchodilators or corticosteroids (spirometry is generally preferred though).

Empiric treatment for gastroesophageal reflux disease (GERD) should be initiated in lieu of testing for patients with chronic cough and reflux symptoms.

Patients should avoid exposure to cough-evoking irritants, such as cigarette smoke.

Further testing may be indicated if the cause of chronic cough is not identified and includes:

- high-resolution computed tomography (CT) of the chest
- referral to a pulmonologist or an allergist

In children, a cough lasting longer than 4 weeks is considered chronic.

The most common causes of chronic cough in children are:

- respiratory tract infections ("bronchitis" and pneumonia)
- asthma
- rhinitis with post-nasal drip
- gastroesophageal reflux disease (GERD)
- aspirated foreign body is relatively rare but must not be missed

Evaluation of children with chronic cough should include chest radiography (CXR) and spirometry (if older than 5 years of age). Skin prick test for environmental allergies can also be indicated.

References:

Evaluation of the patient with chronic cough. Benich Iii JJ, Carek PJ. Am Fam Physician. 2011 Oct 15;84(8):887-92.

Diagnosis of chronic cough in children

"Doctors make mistakes. Can we talk about that?" ED physician Brian Goldman's TED talk

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Dr. Goldman asks if you know your surgeon's "batting average" of operations with good outcomes. He mentions the three words you never want to hear: "Do you remember?" It's a good TED talk:



Every doctor makes mistakes (just like everyone does). But, says Dr. Goldman, medicine's culture of denial (and shame) keeps doctors from ever talking about those mistakes, or using them to learn and improve. Telling stories from his own long practice, he calls on doctors to start talking about being wrong.

Here are some simple steps to avoid medical errors from a patient's perspective (source: CNN):

1. Say: "My name is Mary Smith, my date of birth is October 21, 1965, and I'm here for an appendectomy."
2. Say: "Please check my ID bracelet."
3. Say: "Please look in my chart and tell me what procedure I'm having."
4. Say: "I want to mark up my surgical site with the surgeon present."
5. Be impolite (this particular piece of advice is obviously controversial).

References:

CNN video: Steps to avoid medical errors