Metabolic disorders and food allergies

Question 1

How is a food allergy different than an intolerance

Answer 1

an allergy is an adverse reaction to food ingestion mediated by IgE
Intolerance is difficulty digesting or metabolizing a food

Question 2

Food allergy is the main reason for

Answer 2

Anaphylaxis presenting to the ER

Question 3

What are symptoms of a food intolerance

Answer 3

Gas, bloating, abdominal pain, and diarrhea

Question 4

What are Sx of a food allergy

Answer 4

Immediate* pruritis, urticaria, flushing, swelling of lips, face, throat, nausea, vomiting, cramping, diarrhea, wheezing, light headed, hypotension, syncope

Question 5

How do you diagnose a food allergy

Answer 5

Take an amazing history! have them keep a food journal

They can do a 2 week trial elimination

Question 6

What history is important when suspecting food allergy

Answer 6

Frequency of food eaten 
Quantity eaten 
Ingredients 
How the food is prepared 
GI vs Derm vs Respiratory Sx 
Time in between exposures

Question 7

What labs can you get if you suspect a food allergy

Answer 7

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

Question 8

How do you treat a food allergy

Answer 8

Epinephrine auto-injector (epi pen)- give GOOD instructions
Food avoidance
Allergist referral

Question 9

What is lactose intolerance

Answer 9

Intolerance to lactose containing food
MC in black, hispanic, asian, native american
Prevalence increases w/ age (not common <6 y/o)

Question 10

What normally happens to lactose in the body

Answer 10

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

Question 11

How does lactose intolerance occur

Answer 11

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

Question 12

Primary vs secondary causes of lactose intolerance are

Answer 12

Primary: race, development, congenital deficiency
Secondary: Bacteria overgrowth, infectious enteritis, mucosal injury (celiac, IBD)

Question 13

How does lactose intolerance present

Answer 13

Abdominal pain 
Bloating 
flatulence 
diarrhea 
Borborygmi (really loud BS) 
Sx are affected by diet and vary in severity

Question 14

How do you diagnose lactose intolerance

Answer 14

Sx after lactose ingestion that resolve w/ avoidance

Lactose hydrogen breath test at baseline and q30 min x 3 hours

Question 15

how do you treat lactose intolerance

Answer 15

Lactose free diet
Lactase enzyme helps a bit
Monitor calcium and vitamin D

Question 16

What is G6PD deficiency

Answer 16

X linked disorder where you don’t have G6PD, a RBC enzyme that generates NADPH and protects RBC from breakdown 2/2 oxidative stress

Question 17

G6PD deficiency is associated with

Answer 17

Hemolytic anemia

Nothing is protecting the RBC so they all lyse

Question 18

How does G6PD deficiency present

Answer 18

ASx until a trigger (med, food, acute illness/infx) causes hemolysis
Jaundice, pallor, dark urine, abdominal pain, back pain
Normochromic, normocytic anemia

Question 19

What are common findings on peripheral blood smear of G6PD deficiency

Answer 19

Bite cells 
Heinz bodies (denatured globin chains attached to RBC membrane)

Question 20

What does hemolytic anemia stimulate

Answer 20

Erythropoiesis; Reticulocytes can withstand oxidative stress better than adult RBC
Then you get a spontaneous resolution and reversal of anemia

Question 21

How do you treat G6PD deficiency

Answer 21

Avoid oxidative stress
Remove offending agent (antimalarials, sulfa drugs, abx, analgesics)
Hydration
Transfusion if anemia is severe

Question 22

What is Paget’s disease of bone

Answer 22

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

Question 23

How does Paget’s disease of bone present

Answer 23

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

Question 24

What diagnostics should you get for Paget’s disease of bone

Answer 24

Bone turnover markers
Sr calcium (elevated)
Sr 25-OH vitamin D
Bone scintigraphy (tell you what areas of bone are actually involved)

Question 25

How do you treat Paget’s

Answer 25

ASx: monitor

Bisphosphanates (IV zolendronate has longest response rate before recurrence)

Question 26

Complications of Paget’s disease of bone are

Answer 26

Hypercalcemia 
Renal calculi 
high output HF 
Arthritis 
CN palsies 
Bone tumors

Question 27

What is rickets

Answer 27

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

Question 28

Where are rickets bone deformities MC

Answer 28

Distal forearm
Knee
Costochondral junctions

Question 29

How does Rickets present

Answer 29

Bowing of weight bearing extremities
Skeletal fractures
Proximal myopathies

Question 30

What labs should you get for rickets

Answer 30

Alk Phos: high 
Sr. phosphorus: low 
Sr calcium: low-normal 
PTH: elevated in calcipenic rickets 
25 OH vitamin D

Question 31

What are some radiographic findings for rickets

Answer 31

Wide growth plate at long boned
Decreased radiopacity of long bones
If after growth plate closure: decreased cortical thickness, radiolucency

Question 32

How do you treat rickets

Answer 32

Treat underlying disorder

Vitamin D or calcium supplementation