Metabolic disorders and food allergies Flashcards
How is a food allergy different than an intolerance
an allergy is an adverse reaction to food ingestion mediated by IgE
Intolerance is difficulty digesting or metabolizing a food
Food allergy is the main reason for
Anaphylaxis presenting to the ER
What are symptoms of a food intolerance
Gas, bloating, abdominal pain, and diarrhea
What are Sx of a food allergy
Immediate* pruritis, urticaria, flushing, swelling of lips, face, throat, nausea, vomiting, cramping, diarrhea, wheezing, light headed, hypotension, syncope
How do you diagnose a food allergy
Take an amazing history! have them keep a food journal
They can do a 2 week trial elimination
What history is important when suspecting food allergy
Frequency of food eaten Quantity eaten Ingredients How the food is prepared GI vs Derm vs Respiratory Sx Time in between exposures
What labs can you get if you suspect a food allergy
IgE test (skin prick test or IgE immunoassay) but, think about the pre-test probability; all the things you could find that you now need to work up and treat that weren't even Sx
How do you treat a food allergy
Epinephrine auto-injector (epi pen)- give GOOD instructions
Food avoidance
Allergist referral
What is lactose intolerance
Intolerance to lactose containing food
MC in black, hispanic, asian, native american
Prevalence increases w/ age (not common <6 y/o)
What normally happens to lactose in the body
Lactase is found on microvilli of intestinal membrane.
It breaks down lactose to glucose and galactose
G&G are absorbed by the small intestine
Lactose that isnt absorbed goes into colon to be converted to fatty acid and hydrogen gas by colon bacteria
How does lactose intolerance occur
If you are missing lactase, you have a lactose malabsorption
All the lactose you eat goes into the small intestine and is converted to fatty acid and hydrogen gas
Primary vs secondary causes of lactose intolerance are
Primary: race, development, congenital deficiency
Secondary: Bacteria overgrowth, infectious enteritis, mucosal injury (celiac, IBD)
How does lactose intolerance present
Abdominal pain Bloating flatulence diarrhea Borborygmi (really loud BS) Sx are affected by diet and vary in severity
How do you diagnose lactose intolerance
Sx after lactose ingestion that resolve w/ avoidance
Lactose hydrogen breath test at baseline and q30 min x 3 hours
how do you treat lactose intolerance
Lactose free diet
Lactase enzyme helps a bit
Monitor calcium and vitamin D
What is G6PD deficiency
X linked disorder where you don’t have G6PD, a RBC enzyme that generates NADPH and protects RBC from breakdown 2/2 oxidative stress
G6PD deficiency is associated with
Hemolytic anemia
Nothing is protecting the RBC so they all lyse
How does G6PD deficiency present
ASx until a trigger (med, food, acute illness/infx) causes hemolysis
Jaundice, pallor, dark urine, abdominal pain, back pain
Normochromic, normocytic anemia
What are common findings on peripheral blood smear of G6PD deficiency
Bite cells Heinz bodies (denatured globin chains attached to RBC membrane)
What does hemolytic anemia stimulate
Erythropoiesis; Reticulocytes can withstand oxidative stress better than adult RBC
Then you get a spontaneous resolution and reversal of anemia
How do you treat G6PD deficiency
Avoid oxidative stress
Remove offending agent (antimalarials, sulfa drugs, abx, analgesics)
Hydration
Transfusion if anemia is severe
What is Paget’s disease of bone
Unknown but genetic disorder causing increased bone turnover and overgrowth of bone. MC >55
Increased osteoclast activity= lytic lesion= increased osteoblast activity= disorganized bone formation and abnormal bones and enlarged skeletal deformity
How does Paget’s disease of bone present
ASx w incidental discovery (elevated alk phos w/ isoenzymes indicating bone pathology)
Deep, aching pain worse at night and w/ weight bearing
Bowed tibias
Kyphosis
Chalkstick fractures w/ minimal trauma
increased hat size
HA
What diagnostics should you get for Paget’s disease of bone
Bone turnover markers
Sr calcium (elevated)
Sr 25-OH vitamin D
Bone scintigraphy (tell you what areas of bone are actually involved)
How do you treat Paget’s
ASx: monitor
Bisphosphanates (IV zolendronate has longest response rate before recurrence)
Complications of Paget’s disease of bone are
Hypercalcemia Renal calculi high output HF Arthritis CN palsies Bone tumors
What is rickets
Deficiency in calcium or phosphate leading to altered bone growth (soft, weak bones)
Decreased intake, Malabsorption, or Increased excretion of calcium, phosphate, or vitamin D
Where are rickets bone deformities MC
Distal forearm
Knee
Costochondral junctions
How does Rickets present
Bowing of weight bearing extremities
Skeletal fractures
Proximal myopathies
What labs should you get for rickets
Alk Phos: high Sr. phosphorus: low Sr calcium: low-normal PTH: elevated in calcipenic rickets 25 OH vitamin D
What are some radiographic findings for rickets
Wide growth plate at long boned
Decreased radiopacity of long bones
If after growth plate closure: decreased cortical thickness, radiolucency
How do you treat rickets
Treat underlying disorder
Vitamin D or calcium supplementation
