58

58 CASE 58


A 38-year-old man comes to the clinic complaining of abdominal cramping and diarrhea.


The patient has a 20-year history of alcohol abuse. He is complaining over the past 6 months of passing pale and malodorous stools that are difficult to flush.



PHYSICAL EXAMINATION



VS: T 37°C, P 72/min, R 15/min, BP 120/80 mm Hg

PE: The patient is malnourished, and his liver appears cirrhotic. His sclera are jaundiced.


LABORATORY STUDIES



Plasma analysis: Plasma K+: 3.3 mEq/L (normal: 3.5-5.0 mEq/L)

Serum calcium: 1.9 mEq/L (normal: 2.1-2.8 mEq/L)

pH: 7.30 (normal: 7.35-7.45)

HCO3−: 18 mEq/L (normal: 22-28 mEq/L)

Serum triglycerides: 30 mg/dL (normal: 35-160 mg/dL)

Cholesterol: 130 mg/dL (normal < 200 mg/dL)

Fecal analysis: Positive for fat


DIAGNOSIS


Impaired fat absorption



PATHOPHYSIOLOGY OF KEY SYMPTOMS


Malabsorption is characterized as the inability to absorb ingested nutrients. The defect can be due to inadequate digestion, inadequate transport into the intestinal epithelia, or impaired movement from the intestinal epithelia into the body.


Lipid digestion is complex. Lipids are composed primarily of triglycerides and cholesterol. Ingested lipids interact with bile salts and lecithin in the lumen of the small intestine and become emulsified. Pancreatic lipase, assisted by colipase, digests the triglycerides into free fatty acids and monoglycerides (Fig. 58-1).


image

FIGURE 58–1 Products of lipid digestion are repackaged into chylomicrons in the intestinal epithelium. The combination of hepatic bile salts, pancreatic lipase, and pancreatic colipase digests fats into monoglycerides, free fatty acids, and cholesterol. These digested components enter the intestinal epithelial cells and are transported to the smooth endoplasmic reticulum. The absorbed fats combine with cholesterol and protein to form chylomicrons, which are secreted by exocytosis. The chylomicrons enter the lymphatic lacteals and are transported to the vena cava.

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Jul 4, 2016 | Posted by in PHYSIOLOGY | Comments Off on 58

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