How to evaluate a patient with chronic cough?

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

Chronic Diarrhea - Diagnostic Evaluation

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.

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

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

Chronic insomnia - Lancet 2012 review

Insomnia is a common condition that can present independently or comorbidly with another medical or psychiatric disorder.

Treatment of chronic insomnia

Benzodiazepine-receptor agonists (BzRAs) and cognitive-behavioural therapy (CBT) are supported by the best empirical evidence.

Benzodiazepine-receptor agonists (BzRAs) are effective in the short-term management of insomnia, but evidence of long-term efficacy is scarce. Also, most hypnotic drugs are associated with potential adverse effects.

Cognitive-behavioural therapy (CBT) is an effective alternative for chronic insomnia.

CBT is more time consuming than drug management but it produces sleep improvements that are sustained over time.

However, CBT is not readily available in most clinical settings. Access and delivery can be made easier through:

- telephone consultations
- group therapy
- self-help approaches

How to succeed? Get more sleep



In this 4-minute talk, Arianna Huffington (founder of The Huffington Post) shares a small idea that can awaken much bigger ones: the power of a good night's sleep. Instead of bragging about our sleep deficits, she urges us to sleep our way to increased productivity and happiness -- and smarter decision-making.

References:

Chronic insomnia. The Lancet, Volume 379, Issue 9821, Pages 1129 - 1141, 24 March 2012.
Image source: A halo around the Moon. Wikipedia, GNU Free Documentation License.

Chronic sleep loss decreases performance - One night of good sleep is not enough to recover from chronic sleep deficit

On average, a person needs about eight hours a night to preserve performance.

Acute sleep loss is being awake for more than 24 hours in a row and chronic sleep loss is getting only about four to seven hours of sleep per night.

While most people caught up on acute sleep loss with a single night of 10 hours sleep, those with chronic sleep loss showed deteriorating performance for each hour spent awake.

People are largely unaware that they are chronically sleep-deprived but they are more vulnerable to sudden sleepiness, inattentiveness, and potentially, accidents and errors.

Three days is not enough to recover from chronic sleep loss, but they still do not know how many days or weeks may be needed.

References:
Chronic sleep loss hampers performance. Reuters, 2010.

Image source: Sleeping kitten. Wikipedia, Tilman Piesk, public domain.

Back and forth: Study fails to show link previously found between virus and chronic fatigue syndrome

A UK study analysing samples from patients with chronic fatigue syndrome has found no evidence of a link with a retrovirus (XMRV). The virus was first described in 2006.

Patients with chronic fatigue syndrome, also known as myalgic encephalomyelitis, often report that their condition—a mix of symptoms including extreme fatigue—began after an otherwise normal viral infection.

The xenotropic murine leukaemia virus-related virus (XMRV) was found in 67% of patients with chronic fatigue syndrome in a study reported last year (Science 2009,326:585-9).


The Gift of Time is a short film about the doctors who discovered the XMRV virus and the breakthru potential for prostate cancer.

References:

Study fails to show link previously found between virus and chronic fatigue syndrome. BMJ 2010;340:c1033.

Oral Tolvaptan (Samsca) Is Safe and Effective Treatment for Chronic Hyponatremia

Vasopressin antagonists increase the serum sodium concentration in patients who have euvolemia and hypervolemia with hyponatremia in the short term (30 days), but their safety and efficacy with longer term administration is unknown.

In a study, 111 patients with hyponatremia received oral tolvaptan (Samsca) for 700 days.

The most common adverse effects attributed to tolvaptan were pollakiuria, thirst, fatigue, dry mouth, polydipsia, and polyuria.

Mean serum sodium increased from 130.8 mmol/L at baseline to greater than 135 mmol/L throughout the observation period.

Responses were comparable between patients with euvolemia and those with heart failure but more modest in patients with cirrhosis.

In conclusion, prolonged administration of tolvaptan maintains an increased serum sodium with an acceptable margin of safety.

Samsca (tolvaptan) Black Box Warnings

Appropriate Use

Initiate and re-initiate tx only in hospital with serum Na monitoring.

Monitor Serum Sodium

Osmotic demyelination may occur w/ rapid correction of hyponatremia (faster than 12 mEq/L/24h), resulting in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma, and death; slower rates of correction advised in pts w/ severe malnutrition, alcoholism or advanced liver disease.

Cost comparison of conivaptan (Vaprisol) versus tolvaptan (Samsca)

Conivaptan is administered IV only, the average cost per day is $573.

Tolvaptan is administered PO only, the average cost per day is $300.

References:

Oral Tolvaptan Is Safe and Effective in Chronic Hyponatremia. Journal of the American Society of Nephrology, 2010.

Samsca (tolvaptan) Black Box Warnings. Epocrates.

Cost comparison of conivaptan (Vaprisol) versus tolvaptan (Samsca) (PDF).

Lowest sodium I have ever seen http://goo.gl/QgJmf

Image source: Tolvaptan, Wikipedia, public domain.

Comments from Twitter and Facebook:

@kidney_boy: tolvaptan is safe for the patient but not their wallet at $250 per pill!

Neil Mehta: "It costs a king's ransom to keep the sodium level up! Maybe we should just say "Let them eat Salt"!"

Updated: 10/28/2010

Chronic pancreatitis - The Lancet review

There are two forms of chronic pancreatitis

Chronic pancreatitis is a progressive fibroinflammatory disease that exists in 2 forms:

- large-duct forms (often with intraductal calculi)
- small-duct form

Causes of chronic pancreatitis

Chronic pancreatitis results from a complex mix of:

- environmental factors - alcohol, cigarettes, and occupational chemicals
- genetic factors - mutation in a trypsin-controlling gene or the cystic fibrosis transmembrane conductance regulator (CFTR)
- a few patients have hereditary or autoimmune disease

Management of pain

Pain is the main symptom that occurs in two forms:

- recurrent attacks of pancreatitis (representing paralysis of apical exocytosis in acinar cells)
- constant and disabling pain

Management of the pain is mainly empirical, involving:

- potent analgesics
- duct drainage by endoscopic or surgical means
- partial or total pancreatectomy
- steroids rapidly reduce symptoms in patients with autoimmune pancreatitis
- micronutrient therapy to correct electrophilic stress is emerging as a promising treatment

Steatorrhoea, diabetes, local complications, and psychosocial issues associated are additional therapeutic challenges.

References

Chronic pancreatitis. Dr Joan M Braganza DSc a , Stephen H Lee FRCR b, Rory F McCloy FRCS c, Prof Michael J McMahon FRCS d. The Lancet, Volume 377, Issue 9772, Pages 1184 - 1197, 2 April 2011.
Pancreatitis - JAMA Patient Page, 2012.

Image source: Wikipedia, public domain.