DSA - Disorders of the Small Bowel and Colon (Completed) Flashcards
Paradoxical “diarrhea” described as liquid stool leaking around impacted feces
Overflow incontinence
You observe benign hyperpigmentation of the colon
Melanesis coli Due to chronic use of laxatives
The prescence of the following is inconsistent with medication, IBS, and lactose intolerance mechanisms of chronic diarrhea
- Nocturnal diarrhea
- weight loss
- anemia
- FOBT (fecal occult blood test)
What laboratory tests indicate inflammatory bowel disease?
- erythrocyte sedimentation rate
- C-reactive protein
What measurement determined from a fecal specimen indicates pancreatic insufficiency?
Fecal elastase less than 100 mcg/g
How might you localize a neuroendocrine tumor to visualize it’s location on imaging?
By using somatostatin receptor scintigraphy
What are four neuroendocrine tumors that all have a complication of secretory diarrhea?
- >1 L/day of high-volume watery diarrhea
- normal osmotic gap
- Diarrhea persists during fasting
- VIPoma (VIP) vasoactive intestinal peptide
- Medullary Thyroid carcinoma (calcitonin)
- Zollinger-Ellison syndrome (gastrin)
- (5-HIAA) urinary 5-hydroxyindoleacetic acid
How can small bowel bacterial overgrowth diagnosis be confirmed?
- Breath test (glucose or lactulose)
What is a non-invasive method for the diagnosis of carbohydrate malabsorption?
Hydrogen breath test
ex. Lactase deficiency —> hydrogen breath test
also can perform an elimination trial for 2-3 weeks but this takes longer
Numerous medications can cause diarrhea. What are the common offenders?
- Cholinesterase inhibiitors (-)
- SSRIs
- Angiotensin II-receptor blockers
- PPIs
- NSAIDs
- Metformin
- Allopurinol
- Orlistat (weight loss medication)
Microscopic colitis is a condition of chronic inflammation idiopathic in origin in which 15% of patients have chronic or intermittent watery diarrhea. Most commonly occurs in women between the fifth and sixth decade. What are the two types?
- Lymphocytic colitis
- collagenous colitis
What do we see histologically in microscopic colitis?
- Lymphocytes and plasma cells within the LP
- increased intraepithelial lymphocytes
normal-appearing mucosa on endoscopy
Collagenous colitis is a type of microscopic colitis. Differentiate collagenous colitis from lymphocytic colitis
Collagenous colitis:
- thickened bands of subepithleial collagen (> 10 μm)
Several medications have been implicated as the etiologic agent of microscopic colitis. What are they?
- NSAIDs
- PPIs
- ASA
- SSRI
- ACE (-)
- beta-blockers
removal of these medications resolves diarrhea within 30 days
What is osmotic gap in reference to osmotic diarrhea?
The difference between the measured osmolaltiy of the stool or serum and the estimated stool osmolaltiy
normal: less than 50 mOsm/kg
With reference to osmotic diarrhea what does an increased osmotic gap greater than 75 mOsm/kg indicate?
That the cause of the diarrhea is due to ingestion or malabsorption of an osmotically active substance
What are the most common causes of osmotic diarrhea?
- Carbohydrate malabsorption (lactose, fructose, sucrose)
- Laxative abuse (can be osmotic or secretory)
- malabsorption syndromes
What is one important and easy way you can differentiate whether a patient is havin secretory or osmotic diarrhea?
Osmotic diarrheas resolve during fasting
secretory diarrheas see little change in stool output during fasting
- volume of stool doesn’t reduce during fasting
Patients with carbohydrate malabsorption are often characterized by having chronic postprandial diarrhea. What is postprandial diarrhea?
Diarrhea occurring during or after meals (lunch/dinner)
Secretory diarrhea is a result of either increased intestinal secretion or decreased intestinal absorption. What are the defining characteristics of secretory diarrhea?
- A high-volume watery diarrhea > 1 L/day
- normal osmotic gap
- fasting = little change in stool output
Ingestion of phosphate containing compounds such as laxatives, antacids, or ingestion of magnesium and the use of fat substitute Olestra has been correlated with what?
Incidences of osmotic diarrhea
What are important causes of secretory diarrhea?
- Endocrine tumors that stimulate pancreas/intestines
- Zollinger-Ellison syndrome
- Carcinoid syndrome
- VIPoma
- Medullary thyroid carcinoma
- Bile salt malabsorption (stimulates colonic secretion)
Malabsorptive conditions are conditions in which there is disruption in digestion and nutrient absorption. What are the major malabsorptive conditions?
- Bile salt malabsorption
- Celiac Disease
- Whipple (Tropheryma whippelii, gram +)
- Lactase deficiency
Patient presents with weight loss, osmotic diarrhea, steatorrhea, and nutritional deficiency
Patient has a malabsoprtive condition
- Bilar salt malabsorption
- celiac disease
- whipple
- lactase deficiency
If a patient presents with complaints of significant diarrhea, but no complaints of weight loss what should you be thinking?
This patient most likely doesn’t have a malabsorptive condition
Patient presents with weight loss, gaseous distention, flatulence, and large greasy foul-smelling. You diagnose the patient with pancreatic insufficiency. What is causing this host of symptoms?
Due to malabsorption of triglycerides
Where are bile salts absorbed?
Bile salts are resorbed in the terminal ileum
This process is effected by certain conditions such as Crohn’s disease
While weight loss is minimally seen in bile salt malabsorption. What two things occur as a direct result of bile salt malabsorption?
- Impaired absorption of fat-soluble vitamins (ADEK)
- Can cause a watery secretory diarrhea
What occurs as a result of the impaired absorption of fat-soluble vitamins (ADEK) in bile salt malabsorption
- bleeding tendencies
- Osteoporosis
- Hypocalcemia
What are the classic symptoms seen in Celiacs disease?
- Malabsorption (steatorhea)
- Weight loss and chronic diarrhea
- dyspepsia (indigestion)
- flatulence (colonic bacterial digestion)
- abdominal distention
- muscle wasting (weakness)
- growth retardation
- infants younger than 2
A patient presents with pruritic papulovesicles over the extensor surfaces of the extremities and over the trunk, scalp, knee, and neck.
Dermatitis herpetiformis
seen atypically in Celiacs disease (typical, atypical)
What are atypical symptoms/presentations of Celiacs disease?
- Dermatitis herpetiformis
- iron deficiency anemia
- osteoporosis
What neurologic signs might you see as a result of malabsorption of vitamin B12 and vitamin E in Celiacs disease?
- Peripheral neuropathy
- ataxia
What molecules will be present in a patient with Celiacs disease?
- HLA-DQ2 (95%)
- HLA-DQ8 (5%)
Remember: if you have one autoimmune disorder you are more likely to develop others (myasthenia gravis, sjogren syndrome, Addison disease, Graves’ disease)
What is the means of diagnosis of Celiacs disease?
- abnormal serologic findings (CBC, CMP w/ GGT)
- small bowel biopsy
With serological testing of a patient with Celiacs disease what are some key findings?
- Anemia (CBC)
- Impaired calcium or vitamin D absorption (CMP)
- Imparied fat-soluble vitamin absorption
- Low serum albumin (CMP)
In a patient with Celiac’s disease one of the complications identified based off laboratory findings is anemia. What two types of anemia might you see in Celiac’s Disease?
Microcytic anemia - due to occult blood
- ferritin, iron, iron saturation, TIBC
Megaloblastic anemia - more extensive involvement
- B12, folate
Patients with Celiac’s often have impaired calcium or vitamin D absorption with osteomalacia or osteoporosis. This is identified based off collection of a CMP. What can a CMP tell us?
- Low calcium
- elevated alkaline phosphatase
- Normal GGT —> indicates bone etiology not liver
gamma-glutamyltransferase, an enyzme of the liver
What laboratory findings derived from a CMP would you indicate that a Celiac’s patient had small intestine protein loss or poor nutrition?
- Low serum albumin
- low zinc
- low vitamin B
What two serological tests will identify Celiac’s disease in a patient?
IgA tissue transglutaminase antibody (IgA tTG)
Anti-DGP (IgG antibodies to delaminates gliadin peptides)
- useful for patients who are IgA deficient
- second choice, tTG still number 1
(True/False) Anti-DGP is the preferred method for diagnosing Celiacs because it will indicate prescence of the disease even if the patient is IgA deficient
False
IgA tTG is more specific/sensitive and is number one choice
(True/false) next to IgA tTG and anti-DGP, IgA anti-endomysial antibodies can also be used in the diagnosis of Celiac’s disease
False
IgA endomysial antibodies are no longer used due to failure for labs to standardize to their use
You’re presented with a patient who has all the hallmark typical symptoms of a patient with Celiac’s disease, he even has Dermatits herpetiformis! However when you perform both a IgA-tTG (top choice) and anti-DGP (second choice) you observe that there are no antibodies present? Explain this
Levels of all antibodies become undetectable after 3-12 months of dietary gluten withdrawal. Your patient shouldn’t be on a gluten free diet if you want to check these antibodies.
however, this is a way to check to see if your patient is being compliant once Celiac’s is diagnosed
The standard method for confirmation of Celiacs after serological testing is a mucosal biopsy of what?
Proximal duodenum (bulb) and distal duodenum
What would you see on endoscopy of the proximal and distal duodenum in a Celiacs patient?
Atrophy or scalloping of the duodenal folds
What will you see on histology of a Celiac’s patient?
- intraepithelial lymphocytosis
- extensive infiltration of the LP w/ lymphocytes and plasma cells
- hypertrophy of intestinal crypts
- loss of intestinal villi
Once a CMP is obtained from your patient with Celiacs disease you observe a low serum calcium and elevated alkaline phosphatase. However, a GGT reads normal and you become concerned that your patient may have osteoporosis. What test can be performed to verify whether or not your patient has osteoporosis?
Dual-energy x-ray densitometry (DEXA)
Will indicate whether or not the patient has osteoporosis
Celiac patients must avoid all wheat, rye, and barley. What other complications due Celiac patients tend to have?
Most Celiac patients also have lactose intolerance (either temporarily or permenantely)
(True/false) The most common reason for treatment failure of Celiac’s disease is incomplete removal of gluten
True
What is Whipple disease?
A rare multi-system disease caused by gram positive bacillus tropheryma whipplei
What are the hallmark signs/symptoms of Whipple disease. Which sign/symptom was mentioned in the CIS?
- Lymphadenopathy (LAD) - CIS
- Fever
- Arthralgias*
- Weight loss*
- Malabsorption
- Chronic diarrhea
- abdominal pain
What stain can be used to identify Whipple disease and by what means?
Duodenal biopsy w/ periodic acid Schiff (PAS) positive for macrophages with characteristic bacillus
Source of the infection is unknown
Clinically, what is typically the first symptom seen in Whipple disease and what is the most common presenting symptom?
Non-deforming arthralgias - first symptom
weight loss - most common presenting symptom
What physical exam findings might you see in a patient with Whipple disease?
- Hypotension - late finding
- heart murmurs due to valvular involvement
- peripheral joint inflammation and enlargement (non-deforming arthlragias)