Crohn's disease - 2011 review

Crohn's disease is a chronic inflammatory condition affecting the GI tract at any point from the mouth to the rectum.

Symptoms and signs may consist of:

- diarrhea
- abdominal pain
- fever
- weight loss
- abdominal masses
- anemia

Extraintestinal manifestations of Crohn's disease include:

- osteoporosis
- inflammatory arthropathies
- scleritis
- nephrolithiasis
- cholelithiasis
- erythema nodosum

Laboratory findings

Acute phase reactants, such as CRP and ESR, are often increased with inflammation and may correlate with disease activity.

Levels of vitamin B12, folate, albumin, prealbumin, and vitamin D can help assess nutritional status.

Procedures often used to diagnose Crohn's disease:

- colonoscopy with ileoscopy
- capsule endoscopy
- computed tomography (CT) enterography
- small bowel follow-through

Diagnostic tools for extraintestinal manifestations or complications (e.g., abscess, perforation):

- ultrasonography
- computed axial tomography (CT)
- scintigraphy
- MRI

Medical management

Mesalamine products are used for mild to moderate colonic disease. Antibiotics (e.g., metronidazole, fluoroquinolones) are often used for treatment.

Patients with moderate to severe Crohn's disease are treated with:

- corticosteroids
- azathioprine
- 6-mercaptopurine
- anti-tumor necrosis factor agents (e.g., infliximab, adalimumab)

References

Diagnosis and management of Crohn's disease. Wilkins T, Jarvis K, Patel J. Am Fam Physician. 2011 Dec 15;84(12):1365-75.

Image source: Colon (anatomy), Wikipedia, public domain.

Cirrhosis - 2011 update from Am Fam Physician

Cirrhosis is the 12th leading cause of death in the United States. The mortality rate is 9.7 per 100,000 persons.

The most common causes of cirrhosis are:

- alcohol abuse
- viral hepatitis
- nonalcoholic fatty liver disease is emerging as an increasingly important cause

Patients with cirrhosis should be screened for hepatocellular carcinoma with imaging studies every 6-12 months.

Causes of hepatic encephalopathy include:

- constipation
- infection
- gastrointestinal bleeding
- some medications
- electrolyte imbalances
- noncompliance with medical therapy

Treatment

Lactulose and rifaximin are aimed at reducing serum ammonia levels.

Ascites should be treated initially with salt restriction and diuresis. Physicians should be vigilant for spontaneous bacterial peritonitis.

Patients with acute GI bleeding should be monitored in an intensive care unit, and should have endoscopy performed within 24 hours.

Prevention

Mechanisms to reduce the incidence of cirrhosis:

- treat alcohol abuse
- screen for viral hepatitis
- control risk factors for nonalcoholic fatty liver disease

Cirrhosis: Phil's story (video):



From NHSChoices: Many people enjoy a drink in the pub after work without realising how social drinking can damage health. Phil didn't realise the harm his alcohol intake was doing until he was diagnosed with cirrhosis of the liver. He talks about his experience and the shock he felt at being diagnosed.

References

Cirrhosis: diagnosis, management, and prevention. Starr SP, Raines D. Am Fam Physician. 2011 Dec 15;84(12):1353-9.

Cirrhosis - JAMA Patient Page, 2012.

Pathogenesis of idiopathic pulmonary fibrosis - 2011 Lancet review

Idiopathic pulmonary fibrosis (IPF) is a devastating, age-related lung disease of unknown cause that has few treatment options.

IPF was once thought to be a chronic inflammatory process, but current evidence indicates that the fibrotic response is driven by abnormally activated alveolar epithelial cells (AECs).


Interstitial Lung Diseases (ILD) (click to enlarge the image).

Alveolar epithelial cells (AECs) produce mediators that induce the formation of fibroblast and myofibroblast foci through:

- proliferation of mesenchymal cells
- attraction of circulating fibrocytes
- stimulation of the epithelial to mesenchymal transition

The fibroblast and myofibroblast foci secrete excessive amounts of extracellular matrix (collagen), resulting in scarring and destruction of the lung architecture.


Mechanisms of IPF (click to enlarge the image). Image source: PLoS Medicine, Creative Commons license.

References:

Idiopathic pulmonary fibrosis. The Lancet, Volume 378, Issue 9807, Pages 1949 - 1961, 3 December 2011.

Interstitial Lung Diseases (ILD)

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 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.

Lung cancer - Lancet review

Small-cell lung cancer

Diagnosis relies on histology, with the use of immunohistochemical studies to confirm difficult cases.

Typical patients are men older than 70 years who are current or past heavy smokers and who have pulmonary and cardiovascular comorbidities.

Patients often present with rapid-onset symptoms due to:

- local intrathoracic tumour growth
- extrapulmonary distant spread
- paraneoplastic syndromes
- a combination of these features

Staging aims ultimately to define disease as metastatic or non-metastatic:

- Combination chemotherapy (platinum-based plus etoposide or irinotecan) is the mainstay first-line treatment for metastatic small-cell lung cancer.

- For non-metastatic disease, early concurrent thoracic radiotherapy is indicated.

Prophylactic cranial irradiation should be considered for all patients, even without metastases, whose disease does not progress after induction chemotherapy and radiotherapy.

Despite high initial response rates, most patients eventually relapse. Except for topotecan, few treatment options then remain.

Non-small-cell lung cancer (NSCLC)

The recently introduced 7th edition of the TNM classification relates better to other prognostic factors such as biological markers.

The advances in treatment include:

- a new generation of chemotherapy agents
- a proven advantage to adjuvant chemotherapy after complete resection for specific stage groups
- new techniques for radiotherapy
- new surgical approaches

References:

Small-cell lung cancer. The Lancet, Volume 378, Issue 9804, Pages 1741 - 1755, 12 November 2011

Non-small-cell lung cancer. The Lancet, Volume 378, Issue 9804, Pages 1727 - 1740, 12 November 2011

Image source: A CXR shows a right upper lobe (RUL) mass due to lung cancer. Source: Finger Clubbing due to Lung Cancer. Clinical Cases and Images.

Premenstrual syndrome and premenstrual dysphoric disorder (review)

Premenstrual syndrome

Premenstrual syndrome is defined as recurrent psychological and physical symptoms that occur during the luteal phase of menses and resolve with menstruation. It affects 20-30% of premenopausal women.

Premenstrual dysphoric disorder

Premenstrual dysphoric disorder includes affective or somatic symptoms that cause severe dysfunction in social or occupational activity. It affects 3-8% of premenopausal women.

Proposed etiologies (causative factors) include:

- increased sensitivity to normal cycling levels of estrogen and progesterone
- increased aldosterone and plasma renin activity
- neurotransmitter abnormalities, particularly serotonin

The Daily Record of Severity of Problems is one tool with which women may self-report premenstrual symptoms.

Symptom relief is the goal, and there is limited evidence for the use of:

- calcium
- vitamin D
- vitamin B6 supplementation

Serotonergic antidepressants (SSRIs) (citalopram, escitalopram, fluoxetine, sertraline, venlafaxine) are first-line pharmacologic therapy.

References:

Premenstrual syndrome and premenstrual dysphoric disorder. Biggs WS, Demuth RH. Am Fam Physician. 2011 Oct 15;84(8):918-24.

Image source: OpenClipArt.org, public domain.

Acute pyelonephritis in women (2011 review)

This is a 2011 review from the official journal of the AAFP, American Family Physician:

Acute pyelonephritis is a bacterial infection of the renal pelvis and kidney most often seen in young women.

Symptoms of acute pyelonephritis

Most patients have fever, although it may be absent early in the illness. Flank pain is nearly universal.

Tests for acute pyelonephritis

A positive urinalysis confirms the diagnosis.

Urine culture should be obtained in all patients to guide antibiotic therapy if the patient does not respond to initial empiric antibiotic regimens.

Escherichia coli is the most common pathogen in acute pyelonephritis. In the past decade, there has been an increasing rate of E. coli resistance to extended-spectrum beta-lactam antibiotics.

Imaging, usually with contrast-enhanced CT is not necessary unless there is:

- no improvement in the patient's symptoms
- symptom recurrence after initial improvement

Treatment of acute pyelonephritis

Outpatient treatment is appropriate for most patients.

Oral fluoroquinolone is the initial outpatient therapy if the rate of fluoroquinolone resistance in the community is less than 10%. If the resistance rate exceeds 10%, an initial IV dose of ceftriaxone or gentamicin should be given, followed by an oral fluoroquinolone regimen.

Oral beta-lactam antibiotics and trimethoprim/sulfamethoxazole (TMP-SMX (Bactrim) are inappropriate for therapy because of high resistance rates.

References:

Diagnosis and treatment of acute pyelonephritis in women. Colgan R, Williams M, Johnson JR. Am Fam Physician. 2011 Sep 1;84(5):519-26.
Nephrology Cases