Cilinical Conditions

Question 1

Ehlers danlos disease

Answer 1

Type 3 collagen deficiency (reticular fibres)
-stretchy skin,unstable joints,easy bruising

Type 5 Lysyl oxidase deficiency-no crosslinks formation between collagen

Question 2

Vitiligo

Answer 2

Patches on skin
More apparent on darker skin
-Autoimmune destruction of melanocytes, causing depigmentation

Question 3

Alopecia areata

Answer 3

-hair loss due to autoimmune destruction of hair follicles

Question 4

Psoriasis

Answer 4

• dry,itchy,red,scaly skin
• proliferation of keratinocytes in basal layer causing gross enlargement of prickle cell layer
• abnormal stratum corneal cell number
• loss of barrier, more water loss etc.

Question 5

Malignant melanoma

Answer 5

Aggressive skin cancer mainly caused by UV radiation

• melanocyte mutation
• bad prognosis if penetrates basement membrane (metastasises)

Question 6

OI (osteogenesis imperfecta)

Inheritance

Answer 6

Autosomal dominant

• type 1 collagen defect
• severe cases leads to no conversion of hyaline cartilage to bone
• repeated fractures-leads to bowed long bones, and BLUE sclera
• confused with non accidental INJURY

Question 7

Rickets/osteomalacia

Answer 7

Vit D deficiency (sunlight or diet or decreased function of liver/kidneys)
-decreases reabsorption of Ca2+ in small intestine
-less rigid bones
RICKETS-bowed bones as they are still growing (epiphyseal plates present)
OSTEOMALACIA-no growth plates so bones become brittle and weak

Question 8

Osteoporosis (type 1 and 2)

Answer 8

Type 1-after menopause-less oestrogen so more osteoclast action
Type 2-age-loss of osteoclast function-no remodelling

Question 9

Marfans syndrome

Inheritance and effects

Answer 9

Autosomal dominant

• misfolding of fibrillin leading to more connective tissue
• very tall,arachnodactyly
• aortic rupture (arteries too elastic and just snap-catastrophic haemorrhage)

Question 10

Acromegaly/gigantism

Answer 10

• acromegaly-intramembranous ossification as growth plates are closed (larger FLAT BONES)
• gigantism-intramembranous and endochondral ossification as growth plates are open (LONGER BONES)

Question 11

Cretinism

Answer 11

Neonatal hypothyroidism-retarded and short stature

-give thyroxine

Question 12

Achondroplasia

Inheritance

Answer 12

Autosomal dominant

• deformed fibroblast growth factor receptor, leads to decreased endochondral ossification
• thin epiphyseal growth plates
• short limbs, enlarged forehead

Question 13

Myasthenia gravis

Answer 13

-autoimmune destruction of ACh receptors on motor end plate
-decreased folding so less area available for receptors
-increased width of synoptic cleft
-sudden falling, droopy eyelids, double vision
TREATMENT-immunosuppression and AChesterase inhibitors

Question 14

Muscular dystrophy 2 types

X linked recessive

Answer 14

X linked recessive
Duchenne (total absence of dystrophin)
Beckers (truncation)
-muscle fibres tear on contraction (actin cannot bind to sarcolemma properly)
-Ca2+ induced necrosis
-Pseudohypertrophy (lay down fat and connective tissue in muscle)
-growers sign (brace thighs with arm-hunched over to support weak legs

Question 15

Botulism

Answer 15

Blocks ACh release-no muscle contraction

Question 16

Thyrotoxicosis (hyperthyroidism)

Answer 16

Increased BMR, proteolysis,atrophy

Question 17

Hypoparathyroidism

Answer 17

Decreased Ca2+ absorption—>tetany

Question 18

malignant hyperthermia

Inheritance

Answer 18

Autosomal dominant
Reaction to general anaesthesia (succinylcholine)
Release of Ca2+ from all sarcoplasmic reticulum
Spike in Ox Phosphorylation
huge temp spike –>death
TREATMENT:dantrolene-stops Ca2+ release

Question 19

Multiple sclerosis

Answer 19

Autoimmune destruction of myelin sheath and Schwann cells
-decrease in conduction so loss of function
TREATMENT:B interferon and steroids