6291295
Description
Flashcards by Andrew Street, updated more than 1 year ago
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Created by Andrew Street
about 8 years ago
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| Question | Answer |
| 1814 Osteomalacia is defective m..... of newly formed bone matrix or osteoid. Rickets is defective m..... at the e..... g...... p..... and is found in association with osteomalacia in children. | Osteomalacia is defective mineralization of newly formed bone matrix or osteoid. Rickets is defective mineralization at the epiphyseal growth plate and is found in association with osteomalacia in children. K & C p558. |
| 1810 List causes of vit D deficiency. | There are three main reasons for vit D deficiency: 1) The body has an increased need for vitamin D - pregnant women, breast feeding women, babies being breast fed by vit D deficient mothers, & growing children. 2) The body is unable to make enough vitamin D - people with inadequate sun exposure, the elderly (due to thin skin), people with darker skin, certain medical conditions (Crohn's, coeliac, liver & kidney DS), medications (eg carbamazepine, phenytoin, primidone, barbiturates and some anti-HIV medicines). 3) Not enough vitamin D is being taken in the diet - strict vegetarian or vegan diet, or a non-fish-eating diet. patient.info. |
| 1811 Clinical features of osteomalacia. | * May be asymptomatic * Muscle weakness * Widespread bone P - ^ on weight-bearing & walking * 'Waddling' gait, difficulty climbing stairs & getting out of a chair. K & C p559. |
| 1811 Clinical features of rickets. | * Craniotabes (thin, deformed skull) - seen at birth due to neonatal rickets * Widened epiphyses at the wrists - young children * Harrison's sulcus - groove in the rib cage due to beading at the costochondral junctions ('rickety rosary') * Lower limb deformities - older children. K & C p559. |
| 1812 DDx for bone P. | * Osteoporosis * Bone tumour * Osteomyelitis * Leukemia * Rickets * Hypercalcaemia * Hyperparathyroidism * Paget's DS * Multiple myeloma and on & on & on...... healthline.com |
| 1813 Causes of rickets & osteomalcia. | K & C p559. |
| 1815 Ix for rickets & osteomalacia. | * Serum alkaline phosphatase - ^ in 90% of cases * Low serum Ca2 & phosphate & ^ PTH - each present in 50% of cases * Serum 25-(OH)D3 is low * Serum FGF-23 ^ in many people with tumour-induced osteomalacia * X-ray - see next card. K & C p559. |
| 1815 What characteristic x-ray finding in osteomalacia is shown? | Looser's pseudo #'s. Seen here in both femurs. K & C p559. |
| 1816 Rx for rickets & osteomalacia. | * Vit D replacement - initial loading dose followed by maintenance doses * Supplementary Ca2. K & C p559. |
| 1816 What advice is given to prevent vit D deficiency in young children? | The Department of Health recommends that: Breastfed babies from birth to one year of age should be given a daily supplement containing 8.5 to 10mcg of vitamin D. Babies fed infant formula should not be given a vitamin D supplement until they are receiving less than 500ml (about a pint) of infant formula a day, because infant formula is fortified with vitamin D Children aged 1 to 4 years old should be given a daily supplement containing 10mcg of vitamin D nhs.uk. |
| 1820 Osteoporosis predisposes to skeletal f..... from a quantitative d..... in bone matrix components (o..... & h.....) of bone. | Osteoporosis predisposes to skeletal fractures from a quantitative decrease in bone matrix components (osteoid & hydroxyapatite) of bone. MAAG p454. |
| 1817 Explain T & Z scores and give the definitions of osteoporosis & osteopenia. | T-score = comparison with young adults of the same sex. Z-score = comparison with the expected BMD for the pt's age & sex. WHO definitions: * Osteoporosis = T-score of <-2.5 * Osteopenia = T-score -1.0 to -2.5 MAAG p455. |
| 1818 What are the typical presentations of osteoporosis? | Low impact #'s (eg distal radius (Colles') or femoral neck) and wedge #'s of the vertebrae in the thoracic region causing height loss, kyphosis & P. MAAG p454. |
| 1819 Give a DDx for pathological #'s. | * Osteoporosis * Osteomalacia * Paget's DS * Osteitis * Osteogenesis imperfecta * Benign bone tumours & cysts * Secondary & primary malignant bone tumours. Wiki. |
| 1821 List risk factors for osteoporosis. | * Elderly women - esp if late menarche, early menopause, or long Hx of oligomenorrhoea (eg athletes, anorexia nervosa) due to decreased oestrogen exposure. * Smoking * Alcohol * Steroid * Sedentary lifestyle * +ve FHX * Lean body type. MAAG p454. |
| 1821 List secondary causes of osteopenia. | * Endocrine DS: > Thyrotoxicosis > Cushing's DS > Hypogonadism > Hyperparathyroidism > Secondary amennorrhoea * Rheumatological DS: > Any inflammatory arthropathy esp if Rx with steroids * Gastroenterological DS: > Malabsorption > Cirrhosis * Neoplasia * Drugs: > Steroids > Heparin > Warfarin > Phenytoin * Alcoholism * Rare genetic disorders: > Osteogenesis imperfecta > Hypophosphatasia. MAAG p454. |
| 1822 Outline the Mx of established osteoporosis. | * Ca2 & vit D supplements * Bisphosphonates - alendronate, risedronate, zoledronate (once yearly injection). Inhibit osteoclasts. * Strontium ranelate * Denosumab - monoclonal AB to RANKL * Raloxifene - selective oestrogen receptor modulator that activates oestrogen receptors in bone * Recombinant human PTH peptide 1-34 (Teriparatide) & 1-84 - anabolic agents that stimulate bone formation * HRT - now 2nd line option due to CVS & breast CA risks. K & C p555. |
| 1824 Outline preventative measures for osteoporosis. | * Maximization of BMD (young women): > Adequate Ca2 (1000mg/daily) & vit D (1000IU/daily) > Quit smoking > Minimize alcohol & caffeine intake > Regular weight bearing exercise * Reducing the rate of bone loss - peri- & postmenopausal women & those on long term steroids should have DEXA scans. Start Rx if suitable. * Prevention of #'s. Those with established osteoporosis should be assessed for falls risks (eg drugs causing hypotension, poor vision, poor mobility). MAAG p455. |
| What is shown by the arrow? | Typical osteoporotic # in the vertebrae (T11 in this eg). |
| 1828 Osteitis deformans or Paget’s disease is a focal disorder of bone re..... The initial event of excessive r..... is followed by a compensatory increase in new bone f....., increased local bone blood flow and fibrous tissue in adjacent bone marrow. Ultimately, formation e...... resorption but the new bone is structurally abnormal. | Osteitis deformans or Paget’s disease is a focal disorder of bone remodelling. The initial event of excessive resorption is followed by a compensatory increase in new bone formation, increased local bone blood flow and fibrous tissue in adjacent bone marrow. Ultimately, formation exceeds resorption but the new bone is structurally abnormal. K & C p557. |
| 1829 Describe the main clinical features of Pagets DS. | May affect one or many bones. The most commonly affected in order are: pelvis, lumbar spine, femur, thoracic spine, sacrum, skull, & tibia. Sx inc: * Bone P * Joint P when bone involved is close to a joint * Deformities * Neurological complications - nerve compression (deafness may result from compression of CN VIII), spinal stenosis, hydrocephalus due to blockage of aqueducts * High output cardiac failure & myocardial hypertrophy due to ^ bone BD flow * Pathological #'s * Osteogenic sarcoma (<1%). K & C p557. |
| 1830 Ix to confirm Paget's DS. | * X-ray features - lytic lesions > mixed phase > sclerotic phase > thickening of trabeculae & loss of distinction between cortex & trabeculae (de-differentiation) * Isotope bone scans * ^ Serum alkaline phosphatase with normal Ca2 & phosphate reflects ^ bone turnover * Urinary hydroxyproline excretion is ^. k & C p557. |
| 1831 Rx of Paget's DS. | * Bisphosphonates - mainstay of Rx either IV or PO * Surgery - joint replacement or osteotomy. K & C p557. |
| What is shown by the arrows? | Lateral skull radiograph shows a large geographic, lytic lesion in the left frontal bone (blue arrows). Also seen are islands of bone (white arrows) producing a "cotton-wool" appearance. Typical in Paget's DS seen in early destructive phase and later mixed stages. |
| What is seen in this x-ray? | 'Sabre' tibia as seen in Paget's DS. |
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