Steatorrhea, commonly referred to as fatty stool, is a symptom of fat malabsorption characterized by greasy, bulky, foul-smelling stools that are challenging to flush. It’s not a disease itself, but it indicates something is seriously wrong with the intestines, the pancreas, or the liver, in the background. Untreated steatorrhea leads to severe malnutrition and similar outcomes, making it a serious health concern. Therefore, we need to diagnose it early and treat it timely, to prevent the complications, and also catch deadlier underlying issues such as pancreatic cancer on time.

How does Steatorrhea occur?

Any defect in the digestion of fat or its absorption through the villi of the small intestine gives rise to steatorrhea. In a healthy body, coordination between the liver, intestines, and the pancreas is responsible for digesting a fatty diet. When the fat we eat enters the duodenum, our liver and the pancreas secrete their juices into the small intestine to come in contact with the meal. Liver juice or the bile emulsifies larger fat globules into smaller ones, whereas pancreatic juice, through its lipid-digesting enzymes, further breaks it down into even smaller molecules called fatty acids and triglycerides. These smaller molecules can now be easily absorbed through tiny projections called villi, in our small intestine. But if there is a defect in any step of this process, it makes more fat pass into the stool, causing steatorrhea.

Human Digestive system diagram — Our digestive system, with a close-up of the liver, pancreas, and the duodenum (Image courtesy: Wikimedia Commons; CC license 2.5)

What causes Steatorrhea?

Steatorrhea can arise secondary to a number of problems with our pancreas, liver, or intestines:

Disorders of the Pancreas:

These mainly include the conditions that result in Exocrine Pancreas Insufficiency (EPI), i.e, insufficient production of digestive enzymes, such as:

Chronic Pancreatitis: It’s a long-standing inflammation of the pancreas. By damaging the cells responsible for digestive enzymes, it can cause steatorrhea.
Cystic Fibrosis: It’s a genetic condition characterized by abnormal production and accumulation of mucus in your body, causing breathing and digestive problems. 85% of patients with this condition also have a defect with their exocrine portion of the pancreas.¹
Pancreatic tumors, surgeries, and other conditions that might obstruct the pancreatic ducts or lead to resection of a portion of the pancreas, also produce fat malabsorption and hence, steatorrhea.

Disorders of the Liver & Bile Ducts:

These include conditions that either interfere with the production of bile or its secretion through the bile ducts into the duodenum.

Primary Biliary Cholangitis (PBC): It’s a chronic autoimmune disease that causes inflammation and destruction of the bile ducts within the liver.
Primary Sclerosing Cholangitis (PSC): It’s a chronic inflammatory disease that affects both the intrahepatic and extrahepatic bile ducts.
Cholestasis: It’s a condition in which bile flow from the liver to the duodenum is impaired due to either mechanical or metabolic hindrance.
Liver Cirrhosis
Liver Failure

Disorders of the Intestine:

These include conditions that cause either maldigestion or poor absorption of fats.

Celiac disease: It’s an autoimmune disease in which gluten intake triggers reactions that damage the small intestine.
Crohn’s disease: It’s a chronic inflammation of our gastrointestinal tract that affects nutrient absorption.
Tropical Sprue: It’s a common condition in the tropics. It causes steatorrhea through damaging the intestinal cells, secondary to long-standing inflammation or infection.
Short Bowel Syndrome: This condition arises after the surgical removal of the small bowel. In this, our body fails to absorb a sufficient amount of fat, as the surface area for absorption is reduced.

Infectious Causes of Steatorrhea:

Whipple’s disease: This chronic bacterial infection of the small intestine damages our villi, leading to malabsorption.
Small Intestinal Bacterial Overgrowth or SIBO: It’s a condition with excessive bacteria in the small intestine, which interferes with normal digestion.
Giardiasis: It’s a parasitic infection from contaminated food or water, leading to malabsorption.
HIV Enteropathy: In patients with HIV, the virus penetrates and destroys the cells of the small intestine, hampering fat absorption, causing greasy stools.

Drug-induced Causes:

Certain medications can affect how our bodies digest or absorb fat. These include:

Orlistat: It’s a weight loss medication that acts by blocking the fat-digesting pancreatic enzymes.
Cholestyramine: Doctors prescribe it when you have high cholesterol in your blood. It traps the bile salts, making them unavailable for fat digestion.
Antibiotics such as Neomycin: These drugs indirectly cause malabsorption of fat through several mechanisms, such as disturbing gut flora, damaging intestinal cells, or promoting abnormal bacterial growth.
Chronic laxative use: By speeding up the normal gut motility, these medications give fat less time to absorb, and can even destroy the intestinal cells.

How common is Steatorrhea?

Steatorrhea is a common symptom, but people often don’t report it out of shame, or it goes unnoticed due to the initial asymptomatic phase. Therefore, its exact prevalence is difficult to determine. However, scientists have somehow given an estimate from the prevalence of underlying causes.

For example, chronic pancreatitis is a frequent cause, with a prevalence of 42 per 100,000 cases every year in the US.² Similarly, 1 in every 3000 births suffers from cystic fibrosis, and 85% of cystic fibrosis patients (mainly children) also develop Exocrine Pancreatic Insufficiency, hence steatorrhea.³ Another study indicates that around 78% of liver disease patients have fatty stools.⁴
Also, steatorrhea is more common in developing countries due to a higher incidence of giardiasis and malnutrition-related conditions.

Symptoms of Steatorrhea

The symptoms of steatorrhea involve certain stool characteristics accompanied by symptoms of malabsorption or maldigestion, indicating corresponding underlying pathologies:

Stool Characteristics:

It is possible that initially, you might not have any symptoms at all. Later, your stool may exhibit the following characteristics:

Bulky, greasy, and loose
Clay-colored or pale
Foul-swelling
May float
It may be hard to flush
Presence of foam or oil droplets in the toilet bowl

Associated Symptoms:

These are often non-specific and include:

Pain Abdomen
Bloating
Loose stools
Weight loss
Fatigue

Manifestations of the Underlying Cause:

You might exhibit some case-specific symptoms depending on the cause of your steatorrhea, such as:

Jaundice and pruritis in the case of Primary Biliary cirrhosis or Primary Sclerosing Cholangitis
Oral ulcers, dermatitis herpetiformis, and anemia if celiac disease is the underlying cause
Frequent lung and sinus infections in patients with cystic fibrosis

Signs of fat-soluble vitamins Deficiency:

Since the digestion and/or absorption of fats is compromised in these patients, they often present with a deficiency of fat-soluble vitamins:

Vitamin A deficiency: Dry eyes (Xerophthalmia), night blindness, skin problems
Vitamin D deficiency: Bony pains, weakness, low mood
Vitamin E deficiency: Peripheral neuropathy, brittleness of skin or nails
Vitamin K deficiency: Abnormalities with clotting

Symptoms in Children:

Children often present with other manifestations such as:

Growth retardation
Delayed puberty

How do doctors diagnose Steatorrhea?

Doctors diagnose steatorrhea through a combination of clinical evaluation, lab tests, and imaging studies. The focus is on confirming the presence of fatty stools and then identifying the underlying cause.

Clinical Evaluation:

It starts with a thorough history, in which the doctor explores the characteristics of your poop, their duration, any accompanied symptoms and presence or absence of nutrient deficiency signs. He may also inquire about the medications you might be taking to rule out drug-induced causes of steatorrhea.
Then the doctor proceeds to an in-depth general physical examination, as well as an abdominal examination.

Lab Investigations:

These include qualitative and quantitative tests to confirm the presence of fat in stools.

Qualitative Fecal Fat Test

For this test, you give a stool sample, and the microbiologist examines it under the microscope using Sudan III staining to detect fat globules. A presence of more than 50 neutral fat globules and more than 100 fatty acid globules confirms steatorrhea

Quantitative Fecal Fat Test

This test measures the excretion of fat over 72 hours. Your healthcare provider will advise you to go on a high-fat diet for a given number of days. In the last three days, you will need to collect your stool samples. The lab technologists then examine these stool samples to calculate the Coefficient of Fat Absorption (CFA), i.e, how much amount of ingested fat is absorbed through the small intestine. A value above 92% indicates normal stool characteristics.⁵

Apart from this, your doctor may ask you to undergo these labs:

D-xylose Test: Doctors ask you to drink a sugary solution, called D-xylose. Then they ask for a urine sample and evaluate it for the presence of D-xylose. If positive, the test indicates that pathology lies within the liver or pancreas, as D-xylose was perfectly absorbed from the small intestine and was excreted in urine. If negative, it means there is a problem with the small intestine.
Fecal Elastase test: Doctors prescribe this test to rule out chronic pancreatitis. If fecal elastase in your stool sample is below the required threshold, it means you have exocrine pancreatic insufficiency (EPI).

Imaging & Endoscopy:

Your healthcare provider would ask you to get these done to find out which underlying disorder is causing steatorrhea.

Plain X-ray Abdomen: To detect calcifications in case of chronic pancreatitis.
CT/MRI Abdomen: To get a more detailed view of the pancreas, or look for ductal damage.
Magnetic Resonance Cholangiopancreatography (MRCP): It’s a specialized form of MRI to assess the bile ducts and pancreatic ducts. It may reveal a beaded appearance in the case of Primary Sclerosing Cholangitis (PSC).⁶
Endoscopic Retrograde Cholangiopancreatography (ERCP): It’s an invasive test that combines endoscopy and imaging to assess the pancreatic/biliary ducts. It is helpful in PSC and chronic pancreatitis.
Duodenal Biopsy: Doctors use it to confirm celiac disease when blood tests come positive
Colonoscopy / Workup for Inflammatory Bowel Disease (IBD): Doctors recommend it when PSC is diagnosed, as more than 80% of PSC patients also have IBD.

Other Investigations:

These may include lab tests to diagnose other conditions, such as:

Tissue Transglutaminase IgA and Endomysial Antibodies for Celiac Disease.⁷
Liver Function Test, such as AST, ALT, GGT, to look for the presence and progression of underlying liver pathology.
Anti-Mitochondrial Antibodies (AMA) for Primary Biliary Cirrhosis (PBC).⁸
Glucose or Lactulose Breath Test: It’s a non-invasive screening test for SIBO.
Stool PCR or antigen testing for Giardia.
Small bowel biopsy for Whipple’s or tropical sprue.
HIV testing, if clinically indicated.

Steatorrhea vs. Diarrhea

Steatorrhea and diarrhea are distinct gastrointestinal symptoms, but they are often confused due to overlapping features. Here’s how they differ:

Feature	Steatorrhea	Diarrhea
Definition	Passage of fatty, greasy stools due to fat malabsorption	Increased frequency and liquidity of stools
Stool Appearance	Pale, bulky, foul-smelling, oily; may float and stick to the toilet bowl	Watery or loose; usually doesn’t contain fat
Cause	Fat malabsorption (e.g., pancreatic insufficiency, celiac disease)	Infection, IBS, IBD, medications, food intolerance
Fat Content	High fat content in stool	Normal or low fat content
Associated Symptoms	Weight loss, vitamin deficiencies, bloating	Cramping, urgency, dehydration
Stool Frequency	May or may not be increased	Usually increased
Diagnosis	Stool fat test, imaging, serology, endoscopy	Stool cultures, electrolyte panel, colonoscopy (if chronic)
Treatment Focus	Address fat malabsorption and its cause, dietary support	Rehydration, antidiarrheals, and treat the underlying cause

How do doctors treat Steatorrhea?

Doctors focus on treating the underlying pathology, managing the symptoms, and offering nutritional support.

Addressing the underlying cause:

Pancreatic Enzyme Replacement Therapy (PERT).⁹and dietary recommendations for patients with EPI.
Ursodeoxycholic acid in the case of PBC.¹⁰
Antibiotics like Rifaxamine for SIBO patients, Ceftriaxone for Whipple’s disease, anti-parasitic agents like Metronidazole for Giardiasis, and Anti-retroviral therapy (ART) in case of HIV Enteropathy.
For drug-induced causes, doctors advise discontinuing the culprit drug and replacing it with one that doesn’t interfere with fat digestion.
ERCP with stent dilation for those with PSC.
Strictly gluten-free diet and counselling for celiac disease.

Symptomatic Management:

Your doctor may prescribe:

Antidiarrheals such as loperamide to aid with loose stools.
Probiotics to support gut flora, especially in SIBO patients, after an antibiotic treatment.

Nutritional Support:

In steatorrhea, our bodies have a hard time absorbing fat-soluble vitamins like Vit A, D, E, and K. Therefore, you would need supplementation with these vitamins.
Your nutritionist will advise you to consume medium-chain triglycerides (MCTs), which are absorbed easily and don’t require bile salts.
Apart from this, you might need a high-protein, nutrient-rich diet to combat malnutrition

Dietary Recommendations for Steatorrhea

Dietary modifications depend on the underlying cause. If your steatorrhea is due to excessive consumption of fat, your diet should be devoid of the following fat-rich foods:

Butter
Coffee creamers
Red meat
Whole nuts
Alchohol
Coconut & palm oils

On the contrary, if the cause of your steatorrhea is a malabsorption of fats, then you need to consume a high-fat diet, with the replacement of pancreatic enzymes as required. In this case, make sure your diet consists of unsaturated fats, especially:

Fish oil
Nut butter
Olive oil
Avocados

Also, you can add sources of fat-soluble vitamins to your diet while continuing their oral supplementation. Some good dietary sources of these vitamins are:

Carrots, butter, and fish oil for vitamin A
Oily fish, egg yolks, and liver for vitamin D
Almonds, peanuts, and sunflower oil for vitamin E
Leafy green vegetables such as spinach and kale for vitamin K

Complications of Steatorrhea

If left untreated, steatorrhea can cause the following complications:

Malnutrition:

A long-standing loss of nutrients and fat can produce anemia, vitamin deficiencies, and cachexia. This is particularly alarming in children as they can fall into a state of impaired growth and abnormal cognitive development.

Bone Health Issues:

If calcium and vitamin D aren’t being absorbed well, your bones won’t be left with much mineral content, resulting in conditions like osteoporosis or osteopenia.

Neurological Symptoms:

These are common with a deficiency of vitamin E, vitamin B12(in case of ileal resection), and with Whipple’s disease. These include loss of sensation, muscle weakness, impaired balance and cognition, and vision problems.

What is the prognosis of Steatorrhea?

The prognosis of steatorrhea depends upon the underlying pathology.¹¹

Patients with treatable diseases such as Giardiasis and Celiac disease have a good prognosis due to the reversible nature of these conditions.
On the other hand, patients with cystic fibrosis, PBC, and PSC have a longer course and often a poor prognosis, due to the progressive nature of these etiologies.
Positive prognostic indicators include compliance with dietary and medical therapy.
On the contrary, persistent weight loss, severe malnutrition, or ongoing fat malabsorption may worsen outcomes.

Take-Home message

Steatorrhea is more than just fatty stools – it indicates serious underlying pathologies. Common causes are pancreatic insufficiency, liver conditions, celiac disease, and cystic fibrosis. Symptoms include greasy, bulky, hard-to-flush stools and associated symptoms according to the cause. Diagnosis involves a mix of clinical evaluation, stool fat tests, imaging, antibody testing, and sometimes endoscopy. Treatment is focused on addressing the underlying cause, advising dietary modifications, and managing other symptoms. Since it leads to malabsorption of essential nutrients, particularly fat-soluble vitamins (A, D, E, K), early recognition and intervention are crucial to prevent complications like malnutrition, bone disease, and immune dysfunction.

Refrences

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Steatorrhea: A Window into Hidden Digestive Disorders

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