Diagnosis Flashcards
Diarrhea.Types.Diagnostic-Classification
- Acute
- Chronic
- Inflammatory
- Fatty
- Watery
- Osmotic
- Secretory
- Abnormal-motility
- Exudative
- Ano-rectal-dysfunction
How can we clinically figure out the mechanism of diarrhea?
- Effect of fasting:
- Stops: Osmotic diarrhea
- Continues: secretory.
- Volume of stool:
- Small volume: osmotic, ano-rectal
- Large volume: secretory diarrhea.
- Osmolar gap:
- Large: Osmotic diarrhea
- Small: secretory diarrhea
- Blood and pus in feces: Exudative
- Fecal incontinence: Ano-rectal dysfunction
Diarrhea+Constipation+Abdominal-pain
Recurrent abdominal pain or discomfort and a marked change in bowel habit for at least six months, with symptoms experienced on at least three days of at least three months. Two or more of the following must apply:
- Pain is relieved by a bowel movement
- Onset of pain is related to a change in frequency of stool
- Onset of pain is related to a change in the appearance of stool.
IBS
ROME III critera
Diarrhea.Stool-Osmolar-gap
Osmolar gap = 290 − ([Na+] + [K+]) × 2
- Osmolar gap > 40 suggests osmotic diarrhea
- Osmolar gap < 40 suggests secretory diarrhea
Diarrhea.bloody + abdominal pain + age > 50
If abdominal pain and bloody diarrhea occur together in a patient older than 50 years, consider:
Ischemic Colitis
Diarrhea.chronic
Lasts longer than 4 weeks
Diarrhea.chronic.functional-vs-organic
- Fever
- Weight loss
- Arthritis
- Signs and symptoms of malabsorption
Diarrhea.Chronic.massive
Massive diarrhea WDHA syndrome (watery diarrhea, hypokalemia, achlorhydria
Vasoactive intestinal peptide tumors (VIPomas)
Diarrhea.Endocrine-causes
- Diabetes
- Hyperthyroidism
- Adrenal insufficiency
- Vasoactive intestinal peptide tumors (VIPomas)
- Carcinoid syndrome
- Medullary thyroid cancer
- Gastrinoma
- Mastocytosis
Diarrhea.inflammatory-causes
- Ulcerative colitis
- Crohn disease
- Microscopic colitis
- Eosinophilic gastroenteritis
Osmotic diarrhea: mechanism and examples
osmotically active solutes not absorbed from the gut lume causing passive water loss across the mucosa of the duodenum and jejunum, overwhelming the absorptive capacities of the ileum and colon
Diarrhea stops when oral intake stops
Volume < 1 L/day
Diarrhea.right-sided-valvular-heart-disease
Flushing
Abdominal pain
Wheezing
Right-sided valvular disease
Carcinoid
Diarrhea.Steatorrhea.causes
-
Maldigestion:
- Pancreatic exocrine insufficiency
- Bacterial overgrowth
- Liver disease
-
Malabsorption:
- Celiac sprue
- Tropical sprue
- Whipple disease
- Ischemia
Diarrhea.Steatorrhea.malabsorptive-causes
- Celiac sprue
- Tropical sprue
- Whipple disease
- Ischemia
Diarrhea.WorkUp
- StandardTests
- Fecal leukocytes
- Bacterial culture
- Ova and parasites
- Clostridium difficile toxin assay
- 72-hour quantitative stool collection for volume
- Stool electrolytes for osmolar gap calculation
- Qualitative and quantitative fecal fat on a high-fat diet (e.g., 72 hr, 100 g fat/day)
- Stool phenolphthalein (lax abuse)
- Tests for malabsorption
- d-Xylose testHydrogen breath test
- Tests for lactose intolerance
Diarrhea.WorkUp.d-Xylose
- Measures the absorptive capacity of the proximal small bowel
- Urine and blood are collected after 25 g oral xylose is administered
- Abnormal test suggests small bowel mucosal disease or bacterial overgrowth
- Normal in pancreatic enzyme deficiency
Diarrhea
Pruritus
Flushing
Abdominal pain
Headache
Urticaria pigmentosa—macular lesions that urticate when stroked (Darier’
Mastocytosis
- 24-hr urine histamine and metabolites
- Serum tryptase
- Skin biopsy
GI.bacterial-overgrowth-syndrome.Dx
- 14C-glycocholate breath test and 14C-d-xylose breath tests
- d-Xylose sensitivity and specificity approach 90%
- Hydrogen: Low sensitivity and specificity
- Normalization of Schilling test after antibiotics is highly suggestive
- Gold standard: small bowel aspirate culture
Multisystem-Sx.diarrhea-fever-arthritis-dementia-CHF
Presents with diarrhea, steatorrhea, abdominal pain, weight loss, migratory arthritis, and fever
Neurologic (dementia, ocular disturbances, meningoencephalitis, cerebellar symptoms), cardiac (congestive heart failure, pericarditis, valvular heart disease), and ophthalmologic features may be present
Whipple
Multisystem.GI-predominant
bloating+steatorrhea+dematitis+arthritis+hypocalcemia
Folate may be elevated
Bacterial overgrowth syndrome
A 56-year-old man has had profuse watery diarrhea for 3 months. Measured stool electrolytes are as follows: Na+ 30 mmol/L, K+ 85 mmol/L, Cl− 15 mmol/L, and HCO3− 18 mmol/L. Which diagnosis is least likely?
- Vasoactive intestinal peptide tumor (VIPoma)
- Lactose intolerance
- Laxative abuse
- Celiac sprue
VIPoma
The patient has a stool osmolar gap of 60. Since it is greater than 40, it is suggestive of an osmotic diarrhea. VIPomas cause secretory diarrhea and no osmotic gap. The other three all cause osmotic diarrhea.
Joint-Stiffness.Shoulder
Subacute shoulder pain, globally reduced motion; normal X-ray
Adhesive capsulitis
Joint-stiffness-and-pain.Shoulder
Limited adduction, weakness with active abduction, particularly when the arm is in neutral position
Supraspinatus tear
Pain.back
Pain of lumbar spinal stenosis is relieved by
Leaning forward
Hematologic-abnormalities
Thrombocytopenia + MAHA
TTP
Joint-pain
Arthritis, erythema nodosum, hilar adenopathy
Lofgren’s
Acute sarcoidosis
Multisystem.
purpura+abdominal-pain+bloody-diarrhea+arthritis
HSP
Henoch-Schönlein purpura (HSP), also called immunoglobulin A vasculitis (IgAV), is the most common systemic vasculitis of childhood.
- self-limited disease and is characterized by a tetrad of clinical manifestations that vary in their occurrence and order of presentation
- Palpable purpura without thrombocytopenia and coagulopathy
- Arthralgia and/or arthritis
- Abdominal pain
- Renal disease
DxMethod: is usually based upon clinical presentation. In patients with an incomplete or unusual presentation, biopsy of the affected organ (eg, skin or kidney) demonstrating predominantly immunoglobulin A (IgA) deposition.
Diarrhea.Chronic.Watery
Older person with chronic watery diarrhea (can be severe enough to cause dehydration) with remissions
Microscopic colitis
GI-bleeding.Hematochezia-after-aorto-femoral-bypass
Stable patient
BestTest
CT angio with delayed imaging
If unstable: OR
If stable: CT angio
Dx relies on a high index of suspicion. AEF must be kept in mind as a possible etiology of gastrointestinal bleeding in any patient with known AAA or prior aortic intervention, no matter how long ago. The diagnosis may not be easy to make and is often delayed, particularly when the presence of AAA is unknown
primary aortoenteric fistula (PAEF) and secondary aortoenteric fistula (SAEF).
SAEF can develop following virtually any type of surgical aortic reconstruction, but is most commonly due to erosion of a surgically-placed aortic prosthetic graft into the surrounding bowel. SAEFs can also occur after other aortic interventions, including endovascular aneurysm repair. Rarely, SAEF has been reported to occur in the absence of a prosthetic graft. (See ‘Secondary aortoenteric fistula (SAEF)’ above.)
●
•PAEF arises de novo between the aorta and the bowel, most often the result of compression of an abdominal aortic aneurysm (AAA) against the bowel. Mechanical factors and aortic inflammation/infection may have a role in their development. •
A previously healthy29-year-old woman presents to the emergency department with jaundice. No prescribed medications. Noalcohol use, drug use, or recent use of over-the-counter medications
ALT = 105 U/L (reference range, 10-40 U/L)
AST = 445 U/L (reference range, 20-48 U/L)
Alkaline phosphatase = 18 U/L (reference range, 50-120 U/L)
Total bilirubin = 15.8 mg/dL (reference range, 0.3-1.2 mg/dL)
Direct bilirubin = 4.2 mg/dL (reference range, 0-0.2 mg/dL)
CT: cirrhotic morphology of the liver and small to moderate ascites.
Acute on chronic Wilson disease
notably low alkaline phosphatase levels (due to copper displacing zinc as a cofactor) and elevated indirect bilirubin, consistent with a hemolytic anemia caused by red cell destruction by copper released by hepatocytes. In addition, an AST to ALT ratio greater than 2.2 and an alkaline phosphatase to total bilirubin ratio less than 4 are highly consistent with acute on chronic Wilson liver disease, specifically in the setting of acute liver failure. These ratios can be used to help make the diagnosis quickly when liver transplant must be pursued immediately and traditional copper-based testing will take too long.
Dyspepsia.Alarm-symptoms
- new-onset dyspepsia after age 45 to 55 years
- unintended weight loss
- gastrointestinal bleeding
- iron deficiency anemia
- dysphagia,
- odynophagia
- persistent vomiting, and/or
- family history of upper gastrointestinal malignancy in a first-degree relative
Patients with new-onset dyspepsia after age 45 to 55 years (average age 50 years) and/or those with alarm features should undergo initial endoscopy . Alarm features include unintended weight loss, gastrointestinal bleeding or iron deficiency anemia, dysphagia, odynophagia, persistent vomiting, and/or family history of upper gastrointestinal malignancy in a first-degree relative. In patients with early gastric cancer, symptoms of vague mild epigastric pain and early satiety are indistinguishable from those with functional dyspepsia, and the diagnosis cannot be made on the basis of symptom severity alone. Finally, up to one-fourth of patients with malignancy and dyspepsia do not report alarm symptoms.
Fever.Rodent-Excreta-transmitted
lymphocytic choriomeningitis and hantavirus infections
The deer tick (Ixodes scapularis) is the vector of Lyme disease, anaplasmosis, and babesiosis, and the dog tick (Dermacentor variabilis) is the vector of Rocky Mountain spotted fever and tularemia in the eastern United States. On the West Coast, I. pacificus transmits Lyme disease. Of these infections, only tularemia commonly causes pneumonia. Approximately 10% of cases of plague (Yersinia pestis) in the United States are reported from California. Infection of humans follows exposure to infected fleas in environments where host rodents can seek food and shelter, such as human dwellings. Consideration of pneumonic tularemia and pneumonic plague is important because of the high mortality in the absence of treatment. Aerosolization of mouse excreta is associated with transmission of lymphocytic choriomeningitis and hantavirus infections. Lymphocytic choriomeningitis is typically transmitted by the house mouse and causes aseptic meningitis. North American hantavirus infection causes the hantavirus pulmonary syndrome, which has been reported in both New York and California. After an incubation period of 2 to 3 weeks, an influenza-like prodrome occurs, followed by the development of noncardiogenic pulmonary edema and, in severe cases, renal failure. Coccidioides immitis, the etiologic agent of valley fever, is a dimorphic fungus that is endemic to the San Joaquin Valley. Infection is caused by inhalation of highly infectious soil-living arthroconidia, with symptoms developing after a mean incubation period of 1 to 3 weeks. In addition to fevers and arthralgias, pulmonary involvement is typical in primary infection, with the severity of manifestations proportional to the burden of inhaled arthroconidia.
Fever.Dyspnea
thrombocytopenia, hemoconcentration, and a left shift with atypical lymphocytes.
The most striking abnormalities are the markedly left-shifted granulocytes and thrombocytopenia. The presence of giant platelets suggests peripheral destruction or consumption with thrombopoietin-stimulated marrow reaction. Disseminated intravascular coagulation is unlikely with the normal prothrombin time and fibrinogen level. The elevated partial-thromboplastin time is of uncertain significance but could suggest a preexisting factor deficiency or the presence of a lupus anticoagulant associated with a hypercoagulable state. The hematocrit, at the upper limits of the normal range, could represent mild hemoconcentration; it should be compared with the patient’s baseline level, if available. Thrombocytopenia is commonly seen with rickettsial infections and anaplasmosis. Hantavirus infection is also associated with thrombocytopenia, hemoconcentration, and a left shift with atypical lymphocytes.
Influenza-like-illness: ARDS+thrombocytopenia
hematologic findings of thrombocytopenia, a left-shifted granulocyte series without toxic granulations, atypical lymphocytosis, and hemoconcentration. Lymphoblasts, also described in this syndrome, were not seen.
Hantavirus pulmonary syndrome
The presence of four of these five characteristic hematologic abnormalities was reported to have 98% diagnostic sensitivity for the hantavirus pulmonary syndrome among patients in whom the disease was suspected on clinical grounds by experienced clinicians working in an endemic region.12 Other laboratory abnormalities characteristic of the hantavirus pulmonary syndrome were also present in this patient, including elevations in aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels. Hypoalbuminemia and a low total protein level were not present but are common in severe cases.3,12
Hypoxia, cyanosis,
low pulse oximetry reading, but a normal arterial blood gas Pao2
Methemoglobinemia
methemoglobin (ie, hemoglobin with its iron in the oxidized [Fe+++] state) is suspected when there is clinical cyanosis in the presence of normal arterial pO2.
•The blood in methemoglobinemia has been variously described as dark red, chocolate, or brownish to blue in color, which, if noted during a procedure associated with the use of a topical anesthetic agent, is a valuable clue for making this diagnosis in a timely manner.
●Confirming the diagnosis
•The standard method of assaying methemoglobin utilizes a microprocessor-controlled, fixed wavelength co-oximeter. False positives may occur in the presence of other pigments, including sulfhemoglobin and methylene blue (MB). (See ‘Diagnostic testing’ above.)
•
Pneumonia.Chronic
+ single round opacity
From Indiana
Blastomycosis
headache (most common), malaise, nausea, and dizzines
Meta: NonspecificPresentation, HardToDx, HighRisk
CO poisoning
cooximetry
Carbon monoxide (CO) poisoning is common, potentially fatal, and probably underdiagnosed because of its nonspecific clinical presentation.
quantification by cooximetry of a blood gas sample; standard pulse oximetry (SpO2) is unable to distinguish between oxyhemoglobin and COHb. Blood PO2 measurements tend to be normal because PO2 reflects O2 dissolved in blood, and this process is not affected by CO
Anemia: mild anemia + infrequent pain crises + splenomegaly
Hemoglobin SC disease
Hb SC disease is not as severe as Hb SS disease but more so that sickle trait.
Hemoglobin C — HbC, a beta globin chain mutation, is less soluble than HbA, forming hexagonal crystals (picture 2) rather than the long polymers seen in sickle cell disease (picture 3) [27]. More importantly, HbC, either in the homozygous state (HbCC) or in heterozygous states (HbSC, HbAC) induces red cell dehydration, resulting in red cells with an increased mean corpuscular hemoglobin concentration (MCHC) [17,28,29]. (See “Stomatocytosis and xerocytosis”, section on ‘Hemoglobin C disease’.)
Bleeding disorder: young adult with recurrent bleeding + PTT which corrects after mixing + normal Factor IX
von Willebrand’s
- VWF factor decrease
- Autosomal dominant
- Only 1% of affected are symptomatic
- hree tests are recommended as initial screening tests for VWD (table 2):
●Plasma von Willebrand factor (VWF) antigen (VWF:Ag)
●Plasma VWF activity (ristocetin cofactor activity, VWF:RCo and VWF collagen binding VWF:CB)
●Factor VIII activity (FVIII
INTRODUCTION — Von Willebrand disease (VWD) is the most common inherited bleeding disorder, affecting up to 1 percent of the population as assessed by random laboratory screening, although only approximately 1 percent of these individuals are appreciably symptomatic [1]. It is characterized by mutations that lead to a decrease in the level or impairment in the action of von Willebrand factor (VWF) (table 1). Most cases are transmitted as an autosomal dominant trait that affects males and females equally [2]. There are also acquired forms of VWD that are caused by several different pathophysiologic mechanisms. (See “Classification and pathophysiology of von Willebrand disease” and “Biology and normal function of von Willebrand factor”.)
Hemophilia B
Factor IX deficiency