Malabsorption Disorders

Welcome to today’s episode where we’re diving into malabsorption disorders—conditions where the body has difficulty absorbing essential nutrients, leading to a wide range of symptoms and complications. We'll touch on the causes, types, and treatments.

AudioBoards is an audio-learning platform designed to help you review key topics and clinical vignettes while on the move. With the convenience of headphones, you can listen and learn as you go about your day—whether doing household chores, running errands or during your daily workout. This platform lets you make the most of small pockets of time, transforming mundane tasks into valuable learning opportunities.

Elevate your internal medicine knowledge without letting a busy schedule hold you back. Try AudioBoards today and enhance your ability to retain important information—one audio lesson at a time.

Our goal is to enhance understanding of medical principles while emphasizing that this content is for informational purposes only and not a substitute for professional clinical guidance. Tune in to expand your medical knowledge and stay informed about current trends in medicine!

Transcript

Welcome to today’s episode of AudioBoards. In this session, we’re discussing malabsorption disorders—conditions where the body has difficulty absorbing essential nutrients, leading to a wide range of symptoms and complications.

One of the most common signs of malabsorption is steatorrhea, which is fatty stool. In the lab tests, this shows up as increased fecal fat and low levels of vitamins A, D, and E, along with low serum cholesterol. Another frequent symptom is diarrhea, which involves an increase in stool volume and weight. In lab tests, this can show more fecal fat and an increased stool osmolality gap, suggesting malabsorption of fats and carbohydrates. Malabsorption also commonly leads to weight loss and muscle wasting.

Anemia is another issue that may develop, with microcytic anemia tied to low serum iron, and macrocytic anemia associated with low levels of vitamin B12 or folate. If nerve issues like tingling or muscle spasms are present, lab findings often reveal low calcium or magnesium, which indicates deficiencies in these minerals.

Another concern with malabsorption is bone pain, fractures, or skeletal deformities, which are often due to deficiencies in calcium and vitamin D. A bleeding tendency, such as easy bruising or nosebleeds, can occur when vitamin K is not absorbed properly, which is evident in lab tests showing prolonged prothrombin time or INR. Edema can also occur and is typically linked to low protein and albumin levels in the blood, as well as increased loss of alpha-1-antitrypsin in stool, signaling a protein absorption issue. Finally, milk intolerance, causing bloating, cramps, and diarrhea, is often associated with an abnormal lactose tolerance test, indicating difficulty absorbing lactose.

One of the most well-known malabsorption disorders is Celiac Disease, also known as sprue or gluten enteropathy. This is a permanent condition caused by an immune response to gluten, which damages the proximal small intestine and causes nutrient malabsorption. Classic symptoms include diarrhea, steatorrhea, weight loss, abdominal distension, weakness, muscle wasting, or growth retardation. Other less common symptoms can include dyspepsia and flatulence. Atypical symptoms might also manifest as fatigue, depression, iron deficiency anemia, osteoporosis, short stature, delayed puberty, amenorrhea, or reduced fertility.

When it comes to physical exams, mild cases may appear normal, but in more severe cases, signs of malabsorption are visible, including muscle loss, loss of subcutaneous fat, pallor due to anemia, easy bruising from vitamin K deficiency, hyperkeratosis from vitamin A deficiency, bone pain due to osteomalacia, and neurological symptoms caused by deficiencies in vitamin B12 or vitamin E.

A hallmark skin condition in celiac disease is dermatitis herpetiformis, a pruritic, blistering rash found on the extensor surfaces of the limbs, trunk, scalp, and neck. It occurs in about 10% of patients with celiac disease. For diagnosis, lab findings depend on the extent of the small intestine involved. Proximal small intestine involvement may lead to microcytic anemia, while megaloblastic anemia can occur with involvement of the terminal ileum or associated autoimmune gastritis. Low serum calcium and elevated alkaline phosphatase are also common. A DEXA scan is recommended for all patients to check for osteoporosis. Additionally, prolonged prothrombin time or decreased vitamin A and D levels can be seen.

Serologic tests for IgA tissue transglutaminase-2 antibodies should be done in all patients suspected of having celiac disease. If these are negative, it’s recommended to check IgA levels. Endoscopic mucosal biopsy of the duodenum is considered the gold standard for diagnosing celiac disease, revealing atrophy or scalloping of the duodenal folds.

In terms of treatment, the cornerstone of managing celiac disease is a strict gluten-free diet. Most patients will also experience temporary or permanent lactase deficiency, so avoiding dairy products is necessary. During the initial stages, patients may need dietary supplements such as zinc, vitamins, calcium, folate, and iron, though long-term supplementation is usually not required. For those with osteoporosis, long-term calcium, vitamin D, and sometimes bisphosphonate therapy may be necessary.

Another disorder to consider is Whipple Disease, which is caused by an infection with the bacillus Tropheryma whipplei. It commonly affects white men in their fourth to sixth decades of life. The most frequent symptoms are arthralgias, abdominal pain, diarrhea, steatorrhea, and significant weight loss. Protein-losing enteropathy, leading to hypoalbuminemia and edema, is common, and patients may also experience low-grade fever, lymphadenopathy, and peripheral joint enlargement. Neurologic symptoms can be diverse, ranging from ophthalmoplegia and dementia to cerebellar ataxia, chronic meningitis, myelopathy, and even seizures.

Diagnosis is typically confirmed by an endoscopic biopsy showing PAS-positive macrophages in the duodenum, or by using T. whipplei–specific PCR or immunohistochemistry. The standard treatment involves a course of antibiotics like ceftriaxone or meropenem for 2 weeks, followed by trimethoprim-sulfamethoxazole for up to 12 months. After treatment, repeat biopsies and CSF PCR should be done every six months for at least a year to monitor for relapse. Without treatment, Whipple disease is fatal, but with early intervention, patients can experience dramatic improvements, although some neurological signs may remain permanent.

Next Let’s talk about Bacterial overgrowth in the small intestine. Regardless of the cause, it can lead to malabsorption through several mechanisms. The causes of bacterial overgrowth, include: Gastric achlorhydria , often linked to PPI therapy, Anatomic abnormalities of the small intestine, leading to stagnation of food, Small intestine motility disorders, and Gastrocolic or coloenteric fistula.

Bacterial overgrowth is a particularly important cause of diarrhea in older adults, potentially due to reduced gastric acidity or impaired intestinal motility.

Many patients with bacterial overgrowth don’t show symptoms, but when they do, they tend to be nonspecific. Symptoms may include diarrhea, bloating, flatulence, and sometimes steatorrhea along with weight loss. In severe cases, bacteria in the small intestine can lead to deficiencies in key vitamins and minerals. For example, the bacteria might produce folic acid and consume vitamin B12, which can cause elevated serum folate and decreased vitamin B12 levels. It may also result in deficiencies of fat-soluble vitamins and low serum albumin.

To diagnose bacterial overgrowth, the most definitive test involves an aspirate and culture of distal duodenal secretion to identify if the bacteria count exceeds 1000 organisms per mL. However, this test is not commonly available in most clinical settings. Instead, non-invasive options like breath hydrogen and methane tests are preferred due to their ease of use. In some cases, imaging studies like CT or MR enterography, or even barium radiography, can help identify mechanical factors that might be causing intestinal stasis.

Many clinicians begin treatment with an empiric antibiotic trial, which can serve as both a diagnostic and therapeutic approach. If possible, any underlying anatomic defect causing the overgrowth should be corrected. For treatment, a course of broad-spectrum antibiotics for 7 to 10 days is often prescribed. Common antibiotics used include ciprofloxacin, amoxicillin-clavulanate, trimethoprim-sulfamethoxazole, rifaximin, or a combination of neomycin and metronidazole.

In cases where symptoms come back frequently, cyclic antibiotic therapy may be helpful. However, long-term, continuous antibiotic use should be avoided to prevent resistance.

Next, let’s talk about short bowel syndrome: It occurs after the surgical removal of significant parts of the small intestine. The most common causes in adults include Crohn’s disease, mesenteric infarction, radiation enteritis, volvulus, tumor resection, and trauma.

One key issue in short bowel syndrome is the removal of the terminal ileum, which leads to malabsorption of bile salts and vitamin B12. For patients with low vitamin B12 levels or those who’ve had more than 50 cm of ileum removed, monthly B12 injections are necessary to prevent deficiency.

Bile salt malabsorption can lead to fluid secretion in the colon, causing watery diarrhea. This can be managed with bile salt-binding resins, such as cholestyramine or colesevelam, taken with meals.

The loss of bile salts also results in steatorrhea and malabsorption of fat-soluble vitamins. Management includes a low-fat diet and vitamin supplementation. Unabsorbed fatty acids can bind to calcium, decreasing its absorption and increasing the absorption of oxalate, which can lead to oxalate kidney stones. To counter this, calcium supplements are recommended to bind oxalate and increase serum calcium. Patients are also at risk for cholesterol gallstones due to reduced bile salts.

Antidiarrheal agents like loperamide can help slow intestinal transit and reduce diarrhea. Octreotide is another option that can reduce intestinal transit time, as well as fluid and electrolyte loss. Gastric hypersecretion, which can occur after intestinal resection, should be treated with proton pump inhibitors.

For patients with less than 100-200 cm of proximal jejunum remaining, parenteral nutrition is almost always necessary to meet nutritional needs. An FDA-approved treatment for short bowel syndrome is Teduglutide, a glucagon-like peptide-2 analogue that helps stimulate small bowel growth and absorption. In some severe cases, small intestine transplantation is considered, especially when complications from parenteral nutrition become life-threatening.

Finally, let’s talk about Lactase deficiency. It typically leads to bloating, cramps, and diarrhea after consuming dairy. Diagnosis is usually made with a hydrogen breath test, and many clinicians will recommend an empiric lactose-free diet to see if symptoms improve. For treatment, lactase enzyme replacements are often helpful, and calcium supplementation is recommended for patients who avoid dairy to ensure proper bone health.

That’s all for today’s episode. Thanks for listening to AudioBoards. Stay tuned for more educational content in our next episode! The views and opinions expressed on the AudioBoards Podcast do not necessarily reflect those of our employers. This podcast is for educational purposes only and should not be used to diagnose or treat any medical conditions. It is not a substitute for professional medical advice. Always consult a qualified, board-certified healthcare provider for any medical concern.