MEDICINE 2

Question 1

1. Vitiligo: pathology, presentation, management.

Answer 1

• pathology: chronic skin disorder. autoimmune disorder with aberrant T-cell response against melanocytes.
• presentation: asymptomatic, symmetrical, well-demarcated macules of complete pigment loss. typically affects the face, genitalia, and bony prominences
• Mx: topical steroids, tacrolimus, phototherapy. sunblocks to prevent burning. skin camouflage with psychotherapy may benefit some.

Question 2

2. Urticaria: pathology, presentation, hereditary type, management.

Answer 2

• pathology: localised mast cell degranulation and resultant dermal microvascular hyperpermability. may be mast-cell dependent or independent and/or IgE dependent or independent. triggers include food, drugs, physical triggers, or allergens.
• presentation: wheals (hives, nettle rash), angioedema (inflammation of lips, tongue, eyelids)
• hereditary angioedema: angioedema occurs without urticaria. autosomal dominant involving SERPING1 locus. involves complement and C4 can be used as screening test
• Mx: acute (IM adrenaline, IV steroids) and chronic (non-sedating antihistamines such as loratidine). avoid opiates and NSAIDs as this can worsen

Question 3

3a. Atopic eczema: pathology, histology, presentation, exacerbating factors, management

Answer 3

• pathology: T-cell mediated inflammation (type IV hypersensitivity). reactive chemicals introduced at the epidermis modify self-proteins, turning them into neo-antigens which migrate to the lymph nodes and activate memory T cells. on re-exposure, memory T cells migrate to the surface of the epidermis and migrate to the surface of the epidermis and induce eczema within 24 hours.
• histology: acanthosis (thickened epithelium), hyperkeratosis (scaling), vesicles, spongiosis (intercellular oedema)
• presentation: presents on flexors (elbows, knees, wrists, ankles). repeating scratching and rubbing produces skin thickening (lichenification). HSV and Coxsackie A may cause infection.
• exacerbating factors: soap, bubble bath, woolen fabric, anxiety, stress, dander
• Mx: avoiding irritants. topical therapies usually sufficient to control eczema (steroids, bland moisturiser, soap substitute). FTUs for each area of the body range from 1-1.5 (3-6 months) to 2.5-8 (adult). TCIs (topical calcineurin inhibitors) are also licensed to children and adults >2yr. they are slightly less penetrative but avoid steroid side effects. in unresponsive eczema, systemic immunosuppression (e.g. AZA or MTX) may be used.

Question 4

3b. Other types of eczema (seborrheic, venous, contact).

Answer 4

• seborrheic: areas with high density of seborrheic glands (scalp, forehead, ear). it is an inflammatory condition and not a disease of sebaceous glands. often milder forms (dandruff) are overlooked. treatment options include levodopa, topical azole anti-fungal creams (e.g. ketoconazole shampoo), steroids
• venous: more common in elderly or those with venous thrombosis. signs include haemosiderin, lipodermatosclerosis, varicose ulceration. Mx with bland emollients and short term steroid use.
• contact: consists of allergic and irritant (although almost identical). causes include fragrances, rubber, metal, chemical hair dye, preservatives, cream etc. Mx is with avoiding triggers.

Question 5

4. Psoriasis: pathology, histology, subtypes and their presentations, and management.

Answer 5

• pathology: chronic inflammatory disease linked to TH1, TH17, and CD8 cells.
• histology: typical lesion is a pink-salmon coloured plaque covered with silver white scales. stratum granulosum is thinned with parakeratosis (nucleus retained in upper skin layers). when scale is lifted, multiple tiny bleeding points are observed (Auspitz sign). nail changes include pitting, onycholysis (distal seperation of nail plate), yellow-brown discolouration, subungual hyperkeratosis, dystrophy
• subtypes:
  – chronic plaque: plaques on extensor surfaces.
  — short-term: topical steroids (+/- calcipitriol), long term vitamin D analogue
  – flexural: groin, nasal cleft, and sub-mammary areas
  – guttate (raindrop): explosive eruption seen over the trunk about 2 weeks after a streptococcal sore throat.
  — coal tar for large areas, steroid and calcipitriol for symptomatic areas
  – erythrodermic and pustular: >90% of skin. pustules not infected but filled with sterile inflammatory cells.
• general Mx: topical therapy for 4-6 weeks with re-assessment in 4-6 weeks. refer to rheumatology with signs of psoriatic arthritis, or dermatology after a second topical therapy or with erythrodermic or pustular psoriasis (emergency referral indicated).

Question 6

5a. SJS (Stevens-Johnson syndrome) and TEN (toxic epidermal necrolysis): pathology, categorisation, presentation, management, prognosis

Answer 6

• pathology: type IV hypersensitivity on a spectrum (SJS less severe, TEN most severe). characterised by varying extent of blistering/epidermal detachment from the dermis and mucosal ulceration.
• categorisation:
  – <10% is SJS
  – 10-30% is SJS-TEN overlap syndrome
  – >30% with all mucosal sites is TEN
• presentation: almost always initiated by a drug. initially non-specific (malaise, myalgia, fever, cough), followed by tender macropapular erythema on the torso with mucosal inflammation. common triggers include sulfonamides, AEDs, immune modulators, and NSAIDs. Nikolsky’s sign (rubbing gently on lesions causes epidermis to shed).
• Mx: as for extensive burns, patients are at risk of sepsis due to skin failure and may need intensive care. triggering medication stopped immediately. supportive measures may be used to dampen immune response (antihistamines, IV Ig, cyclosporin, steroids)
• prognosis: SCORTEN score for prognosis with TEN (1 pt each):
  – age > 40
  – tachycardia >120
  – neoplasia
  – initial detachment >10%
  – urea >10mmol/l
  – CHO3 <20mmol/l
  – glucose >14mmol/l
  – 0-1 3%; 2 12%; 3 35%; 4 58%; 5+ 90%

Question 7

5b. DRESS (drug reaction with eosinophilia and systemic symptoms): pathology, triggers, presentation, management.

Answer 7

• pathology: similar to SJS/TEN but takes much longer to develop (2-6 weeks) and covers >50% of body surface.
• triggers: AEDs, allopurinol, anti-psychotics, sulfonamides
• presentation: rash >50% of body with systemic features (facial oedema, fever, lymphadenopathy, hepatosplenomegaly). additional features include
  – pulmonary: pleural effusion, pneumonitis, pneumonia
  – hepatic: ranges from asymptomatic to liver failure
  – renal: acute interstitial nephritis
  – cardiac: myositis
• Mx: stop offending drug immediately, 3 month course of steroids

Question 8

6a. Lichen planus: pathology, triggers, presentation, management.

Answer 8

• pathology: unknown aetiology, probably of autoimmune origin
• triggers: viral infections, beta-blockers, gold, levamisole, ACE inhibitors, sunlight
• presentation: 6 P’s (pruritic, purple, polygonal, planar, papules, plaques). white lines/dots can connect these (Wickham striae). Koebner phenomenon (new lesions at sites of trauma) may present.
• Mx: may resolve 1-2yr after onset. may rarely progress to malignancy (SCC). Lesions may respond to topical steroids or TCIs. other treatments include MTX, oral retinoids, AZA, and thalidomide.

Question 9

6b. Lichen sclerosus: pathology, presentation, indication for biopsy, management.

Answer 9

• pathology: triggers include autoimmune, infection, trauma, or moist environments. bimodal incidence (puberty and perimenopause).
• presentation: intensely pruritic, shiny white lesions on the vulva or glans penis
• biopsy: clinical examination sufficient for diagnosis unless:
  – failure to respond to treatment
  – suspicion of neoplasia (e.g. VIN)
  – extragenital LS
  – pigmented areas (to exclude melanoma)
• Mx: topical steroids and emollients, or TCIs. in males, may require circumcision with prolonged phimosis

Question 10

7a (tumours of the skin): benign tumours: moles, seborrheic keratosis, acanthosis nigricans, skin tags

Answer 10

• moles (melanocytic naevus): caused by activating mutation in Ras pathway (importantly BRAF). size is the most important factor in relating risk to melanoma progression
• seborrheic keratosis: harmless, due to mutations in FGFR3, extremely common in older individuals
• acanthosis nigricans: associated with obesity, diabetes, and cancers as part of a paraneoplastic syndrome (e.g. GI adenocarcinoma).
• skin tags (aka acrochordon, squamous papilloma, fibroepithelial polyp): common in middle-old age, often attached to skin via slender stalk. fibro-vascular core covered by benign squamous epithelium

Question 11

7b (tumours of the skin): pre-malignant syndromes: actinic keratosis, Bowen’s disease, keratocanthoma, familial atypical multiple mole melanoma (FAMMM).

Answer 11

• actinic keratosis: hyperkeratotic, parakeratotic (retains nucleus) sun-damaged skin leading to SCC. may produce a ‘cutaneous horn’. spontaneous regression is ~5%, imiquimod eradicates ~50%. other options include cryotherapy, 5-FU cream, and PDT.
• Bowen’s (aka carcinoma in situ): typically affects the lower limbs (rarely torso, genitals, or anus). rarely progresses to SCC. Mx as for actinic keratosis.
• keratoacanthoma: occur in sun-exposed skin later in life with central necrosis and ulceration. should be excised as they closely resemble SCC
• FAMMM: typically occurs in childhood with many melanocytic naevi all over the body. suspicious moles should be removed as can progress to many types of cancer

Question 12

7c (tumours of the skin): squamous cell carcinoma (SCC): pathology, presentation, management.

Answer 12

• pathology: usually discovered in early stages (>95%). risks include UV, immunosuppression, HPV5/8, Bowen’s, actinic keratosis
• presentation: rapid growth, ‘flat’ lesions.
• Mx: examination of lymph nodes for metastasis is essential as SCC has a high tendency to metastasise. treatment is with surgical excision (minimal margin of 5mm). radiotherapy may also be used.

Question 13

7d (tumours of the skin): basal cell carcinoma (BCC): pathology, presentation, management.

Answer 13

• pathology: most common skin malignancy worldwide. aggressive tumours arising from activation of the Hedgehog signalling pathway.
• presentation (‘rodent ulcer’): slowly growing, enlarging shiny nodule on the head/neck bleeding following minor trauma. these are pearly papules with telangiectasia and central ulceration.
• Mx: treatment of choice is wide excision (e.g. Mohs surgery). other options include radiotherapy, cryotherapy, photodynamic therapy, imiquimod, and vismodegib (dependent on size and location of tumour)

Question 14

7e (tumours of the skin): melanoma: pathology, presentation, clinical types, prognostic measures, management.

Answer 14

• pathology: most dangerous of all skin cancers. risks include UV, pale skin, genetic syndromes, family history. genetic aberrations include CDKN2A, PI3K pathway (RAS, PI3K, AKT, MDM2, mTOR), BRAF pathway (RAS, BRAF, MEK, ERK), and telomerase activation
• presentation [ABCDE]: asymmetry, borders (irregular), colour (varying), diameter (increasing), and evolution (over time).
• clinical types [4]:
  – superficial spreading: large, flat, irregularly pigmented lesion
  – nodular: bleeds and ulcerates, most aggressive type
  – acral lentiginous: palm, sole of foot, under nail
  – lentigo maligna: irregularly shaped lesion growing slowly over years
• prognostic measure (Breslow thickness): probability of metastasis is related to depth of invasion. removal and examination of lymph nodes (sentinel lymph node) yields additional prognostic information
• Mx: all melanomas >1mm should be referred. surgery is the only curative option. 1cm margin for thin lesions and 3cm for thicker. specific inhibitors (e.g. PI3K, AKT, BRAF) also exist.

Question 15

7f (tumours of the skin): mycosis fungoides: pathology, presentation, management

Answer 15

• pathology: a T-cell lymphoma (with no fungal involvement). may show atypical CD4+ cells (Sezary cells) in Sezary syndrome on biopsy
• presentation: pruritic scaly patches typically on the buttocks which may resemble eczema (asymmetry and atrophy are useful clues)
• Mx: corticosteroids, nitrogen mustard, low dose PUVA.

Question 16

8a (bullous disorders): pemphigus vulgaris: pathology, histology, presentation, investigations, management.

Answer 16

• pathology: bullous disorder type II hypersensitivity caused by IgG4; these dissolve dermosomes (intercellular attachments) formed of desmoglein 1 and 3. most common in Ashkenazi Jews and Indians.
• histology: apoptosis and proteases cause acanthosis (cells break apart), leading to bullae. hemidesmosomes (dermis-epidermis) are not affected, causing ‘tombstoning’.
• presentation: blistering bullae on the mucosa and skin, particularly the scalp, face, axilla, groin, trunk, and mouth. bullae may rupture easily leaving erythematous erosions. Nikolsky’s sign is positive (lateral pressure to bullae causes epidermis and dermis to separate)
• investigations: skin biopsy may be used to look for acanthosis and tombstoning. direct immunofluorescence may be used to tag IgG4 autoantibodies
• Mx: steroids, steroid-sparing agents (MTX, AZA), or rituximab

Question 17

8b (bullous disorders): bullous pemphigoid: pathology, presentation, management.

Answer 17

• pathology: IgG autoantibodies attack hemidesmosomes (unlike pemphiguS, which attacks desmosomes), meaning lesions do not rupture easily and heal without scarring.
• presentation: bullae on the thighs, flexor forearm, axilla, groin, and lower abdomen. mucosal involvement is uncommon.
• Mx: steroids, then steroid-sparing agents (MTX, AZA). topical steroids may be used in milder cases.

Question 18

8c (bullous disorders): epidermolysis bullosa: pathology, investigation, and management.

Answer 18

• pathology: different types include simplex (>75%), junctional, dystrophic, and aquisita. EB simplex is an autosomal dominant disorder affecting keratin 5 and 14. there is a proclivity to form blisters at sites of rubbing, trauma, or pressure.
• Ix: should be undertaken at a specialist centre. includes ultrastructural analysis (electron microscopy), immunohisto-chemistry, and genetic counselling. prenatal diagnosis is available for more severe forms.
• Mx: gene therapy and bone marrow transplantation are undergoing clinical trials.

Question 19

9. Acne vulgaris: risk factors, pathology, lesion classification, management.

Answer 19

• risk factors: seen primarily in mid-late teenage years. may be induced or exacerbated by drugs (steroids, sex hormones [testosterone, gonadotrophins, contraceptives]), heavy clothing, cosmetics, and tropical climates.
• pathology: four main components:
  – keratinisation of follicles
  – hypertrophy of sebacous gland (due to androgens in puberty)
  – propionibacterium acnes
  – secondary inflammation of involved follicle
• lesion classification:
  – noninflammatory: open and closed comedones. blackheads are open (Open = O2 causing necrotising change) and whiteheads are closed (keratin plug is deeper within the skin)
  – inflammatory: papules and pustules (inflamed lesions; pustules have a yellow/white pus tip), nodules, and cysts.
  – scars
• Mx: depends on clinical severity (mild or moderate) and type (noninflammatory or inflammatory).
  – mild: noninflammatory (comedones = topical retinoid); inflammatory (papules, pustules, nodules, cysts = topical benzoyl peroxide). review at 12 weeks. if in remission consider stopping; if poor response, switch drugs then combine. consider adding antibiotic in inflammatory type.
  – moderate: after second 12 week review of mild acne or straight away at initial presentation. combine topical benzoyl peroxide and oral antibiotic (e.g. a tetracycline).
  — review at 8 weeks and stop antibiotic at 12 weeks in remission, or switch benzoyl peroxide to topical retinoid and continue antibiotic.
  – severe: oral isotretinoin (potent teratogen so females must have contraception).

Question 20

10. Rosacea (acne rosacea): exacerbating factors, pathogenesis, management.

Answer 20

• exacerbating factors: middle-age and older age, female sex, hot drinks, alcohol, sunlight, steroids
• pathogenesis: four main steps. the commensal mite Demodex folliculorum is suspected to be one of the primary triggers.
  – 1. flushing episodes
  – 2. persistent erythema, telangiectasia
  – 3. pustules and papules (like inflammatory acne vulgaris)
  – 4. rhinophyma (permanent thickening of nasal skin)
• Mx: depends on severity and key features.
  – mild, papules and pustules: topical metronidazole, azelaic acid cream/gel
  – flushing: topical brimonidine, cosmetic concealers
  – telangiectasia: vascular laser surgery
  – severe disease: oral antibiotic (e.g. tetracycline)
  – rhinophyma: refer to dermatology for surgical debulking

Question 21

11. Erythema nodosum: definition of panniculitis, definition of erythema nodosum, causes

Answer 21

• panniculitis: inflammatory reaction in subcutaneous adipose tissue. most types affect the lower legs.
• erythema nodosum: poorly defined, extremely tender erythematous plaques that are more easily palpated than seen
• causes: beta-haemolytic strep, TB, histoplasmosis, leprosy, sarcoidosis, IBD, and neoplasia

Question 22

12. Disorders of nails: clinical signs and their causes.

Answer 22

• dystrophy: psoriasis, fungal infection, trauma
• pitting: psoriasis, alopecia, atopic eczema, trauma
• onycholysis (distal nail separation): psoriasis, hyperthyroidism, trauma, tetracyclines
• koilonychia (spoon shaped nails): iron deficiency anaemia
• leuconychia: hypoalbuminaemia
• sub-ungual hyperkeratosis: tinea, psoriasis, trauma

Question 23

13a. Hair growth: stages of hair growth, hirsutism (causes, investigation, management) and hypertrichosis.

Answer 23

• stages of hair growth: anagen (90%, 2-6y for scalp, 30-45 days for other areas) - hair growth phase, ~1cm/month. catagen (3%, 2-3wk) - transitional phase. telogen (7%, 100+dy) - rest phase, 25-100 hair shed/day.
• hirsutism: causes (PCOS, Cushing’s, CAH, obesity, adrenal or ovarian tumours, phenytoin, steroids), Ix (Ferriman-Gallwey score of 0-4 in 9 body areas, >15 indicates)

Question 24

13b. Hair loss: androgenic, alopecia, telogen effluvium

Answer 24

• androgenic: young men, frontal receding and thinning. treatment may not be required but can include 5a-reductase inhibitors (e.g. finasteride). 1/3 won’t respond and s/e include loss of libido
• alopecia: autoimmune disease with patchy hair loss. steroids may retrigger growth while topical diphencyprone can be useful in extensive disease. other options include wigs and support groups
• telogen effluvium: diffuse hair loss seen 3 months after pregnancy or severe illness. stress puts all hairs into telogen phase simultaneously. hair recovers fully and normal cycle resumes within a few months.

Question 25

14. Pressure ulcers: risk factors and epidemiology, grading, presentation, management, prevention, and neuropathic ulcers

Answer 25

• Rx & epidemiology: occurs in elderly, immobile, unconscious, or paralysed patients due to ischaemia from sustained pressure over a bony prominence. Rx include prolonged immobility, decreased sensation, vascular disease, and poor nutrition (particularly vitamin C deficiency).
• grading (I - IV):
  – I: non-blanching erythema of skin
  – II: partial thickness skin loss (epi-dermis)
  – III: full thickness loss (hypodermis but not fascia)
  – IV: full thickness with involvement of muscle, bone, tendons, or joint capsule
• presentation: early signs of red/blue discolouration, further reddening and loss of skin
• Mx: bed rest, air filled cushions, pressure-relieving mattresses or beds, nutrition, non-irritant occlusive moist dressings, analgesia, debridement, Mx underlying condition
• prevention: based on Norton or Waterlow Pressure Ulcer Risk scale. based on e.g. physical, mental state, activity, mobility, and incontinence
• neuropathic ulcers: pressure areas of feet due to repeated trauma, most commonly found in diabetics due to peripheral neuropathy. Mx with ulcer cleaning and removing pressure/trauma from the area.

Question 26

15. Lymphedema: presentation, causes, management.

Answer 26

• presentation: chronic, non-pitting oedema caused by lymphatic insufficiency. most commonly affects the legs, causing them to become enormous and the patient being unable to wear normal shoes.
• causes: primary (e.g. inherited deficiency), secondary (obstruction due to Milroy’s disease, fliarial infection etc.)
• Mx: compression stockings, physical massage. if recurrent, long-term antibiotics to avoid cellulitis.

Question 27

16a. Impetigo: pathology, presentation, management, complications

Answer 27

• pathology: bacterial infection caused by staph aureus. bacterial toxins cleave desmoglein 1 leading to epidermal injury and oedema.
• presentation: pustules form a honey-coloured crust most commonly perioral, but also can affect the hands and rest of face.
• Mx: rigourous hand washing, topical fusidic acid; flucloxacillin or erythro/clarithromycin if widespread. children should avoid school until lesions are dry, or until 48hr after antibiotics have been commenced
• complications: glomerulonephritis, osteomyelitis, sepsis

Question 28

16b. necrotizing fasciitis: pathology and risk factors, presentation, management.

Answer 28

• pathology: rapidly spreading deep infection of subcutaneous tissue. classified into 2 types based on pathogen: type 1 (mixed aerobes and anaerobes) and type 2 (strep pyogenes). Rx include recent trauma, burns, or soft tissue infection; DM (esp. SGLT-2 inhibitors); IV drug use; immunosuppression
• presentation: acute pain, swelling, and erythema; pain is out of keeping with physical features. most common site is the perineum (Fournier’s gangrene). skin is extremely tender to touch. late features: skin necrosis, crepitus/gas gangrene, fever, tachycardia.
• Mx: dermatologic emergency requiring debridement and antibiotics (clindamycin and penicillin). mortality is ~20%.

Question 29

16c. Tinea: fungology, types and their presentations, management.

Answer 29

• fungology: tinea are dermatophytes which grow on soil and animals.
• types and presentations:
  – tinea captis: scalp
  – barbae: beard area
  – corporis (ringworm): main body
  – cruris: obese men in inguinal area (particularly in warm weather)
  – pedis (athlete’s foot)
  – versicolor: common in young adults. pink-beige scaly macules on torso. ‘meatballs and spaghetti’ on skin scraping microscopy
  – unguium: nails
• Mx: localised tinea treated with antifungals (e.g. miconazole and terbinafine). widespread treated with the oral version for 1-2 months.

Question 30

16d. Scabies: presentation, management, crusted (Norwegian) scabies

Answer 30

• presentation: pruritis worse at night, ‘knots on a rope’ sign
• management: scabicide (e.g. 5% permethrin, malathon) applied overnight all over the body under the neck, repeated after one week. all clothes should be washed at 60 deg. pruritis may persist for up to 4 weeks.
• crusted (Norwegian) scabies: more severe form where immunosuppressed individuals may carry a huge number of mites and may cause an outbreak. may resemble eczema or psoriasis. Mx with barrier nursing and careful application of scabicide.

Question 31

16e. Verrucae (warts): pathology, investigation, management.

Answer 31

• pathology: squamoproliferative disorders caused by HPVs. transmission is by direct contact or autoinnoculation. key types include
  – HPV 5&8: SCC
  – HPV 6&11: anogenital warts
  – HPV 16: carcinoma in situ appearance of genital lesions which regresses spontaneously
• Ix: viral typing by FISH or PCR
• Mx: generally self-limiting and will regress within 6m-2y. monitoring required for highly pathogenic types.

Question 32

16f. Cellulitis and erysipelas: presentation and pathogens, risk factors, investigations, management.

Answer 32

• presentation: infection of skin. tender confluent areas of skin with fever and malaise. erisyipelas is superficial and caused by strep pyogenes, and cellulitis is deep and caused by staph aureus.
• Rx: lymphedema, leg ulcers, intertrigo and traumatic wounds
• Ix: serological tests (e.g. anti-streptolysin O, anti-DNAse B)
• Mx: flucloxacillin or erythromycin

Question 33

17. Osteoporosis: definition, physiology, risk factors, investigation (and indications for), management.

Answer 33

• definition: a weakening of bone, defined as bone mass <2.5 standard deviations below mean peak bone mass. significantly increases risk of atraumatic fracture.
• physiology: peak bone mass is reached in early adulthood and is dependent on many factors (physical activity, muscle strength, diet, hormones). age-related bone mass is normal as osteoblasts lose efficiency with age.
• Rx: oestrogen deficiency (e.g. post-menopause), glucocorticoids, vitamin D deficiency, previous fracture, aging, smoking, and falls
• Ix: indications: radiographic osteopenia, previous fragility fracture (<75), glucocorticoid therapy (<65), low BMI (<19), maternal history of hip fracture, BMD-dependent (CKD, low vitamin D, COPD). Best options for Ix are DEXA and CT-scan.
• Mx: bisphosphonates (e.g. alendronate, risedronate). well tolerated, s/e include oesophagitis, worsening of CKD, and osteonecrosis of jaw. other options are more expensive or carry more risk, and include denosumab, strontium ranelate, recombinant human PTH.

Question 34

18. Paget’s disease of bone: physiology of bone remodelling, pathogenesis of Paget’s, clinical features, investigation, management

Answer 34

• physiology: osteoblasts lay down bone matrix while osteoclasts break it up. osteoblasts release RANKL, which binds to RANK on osteoclasts and stimulates them. broken down bone releases OPG, which binds and inhibits RANK on osteoclasts.
• pathogenesis: Paget’s occurs in three main stages: 1. osteolysis (OC > OB), 2. mixed (OC = OB), and 3. osteosclerotic (OC < OB). rapid degradation of bone by OCs causes rapid regeneration by OBs, creating structurally unsound bone. the hallmark in histology is prominent ‘cement lines’).
• clinical features: >80% is asymptomatic. signs include bone pain caused by compression of nerves by bone (high yield: compression of CN VIII causes deafness), lion face, platybasia, bowing of femurs and tibiae, and HFpEF. tumours commonly develop as a complication, most often sarcoma.
• Ix: clinical, radiographic (thick cortices), high ALP and Ca2+, low vitamin D
• Mx: calcitonin and bisphosphonates. both associated with flu-like symptoms. surgery may be needed

Question 35

19. Rickets and osteomalacia: vitamin D metabolism, pathology, presentation, investigations, management.

Answer 35

• vitamin D metabolism: UVB absorbed via the skin and is transported to the liver by D-binding protein (DBP). 25-OHases convert vitamin D to 25(OH)D in the liver, which is converted to 1,25(OH)2D in the kidney. 1,25(OH)2D causes Ca2+ absorption in the GI tract and Ca2+ release from bone by activating RANK on osteoclasts.
• pathology: deficiency of vitamin D, phosphate deficiency (e.g. refeeding syndrome, alcohol, malabsorption, renal tubular acidosis)
• presentation: bone pain (pelvis, spine, femurs), pathological fractures, hypocalcaemia (peripheral nerve pathology, muscle cramps, irritability, fatigue, seizures, brittle nails).
• Ix: ALP and PTH elevated, Ca2+, PO4-, and 25-hydroxyapatite depleted. radiographs show depleted mineralisation and pseudofractures.
• Mx: vitamin D, calcium and phosphate supplementation. done in two stages: loading and maintenance stages.

Question 36

20. Osteomyelitis: pathology, presentation, investigations, management.

Answer 36

• pathology: osteomyelitis is inflammation of bone, almost always secondary to infection. most often caused by fractures which allow bacterial spread.
  – Staph aureus is the most common cause (skin commensal)
  – Haemophilus and Salmonella are more common in those with sickle cell and children
  – Syphilis and TB can cause rare, complicated cases
• presentation: systemic illness with malaise, fever, chills, leukocytosis. localised, throbbing pain over the affected area.
• Ix: radiographic (MRI, bone scan, bone biopsy) findings of a lytic focus with sclerotic findings.
• Mx: immobilisation and antibiotics (IV teicoplanin + flucloxacillin)

Question 37

21. Tumours of bone (see table in summary notes): type (benign / malignant), pathology, who it affects, x-ray signs.

Answer 37

• osteochondroma: benign, affects epiphyses, men 3:1, exocytosis (bone stalk) on x-ray
• osteoid osteoma / osteoblastoma: benign, cortical bone of appendicular skeleton, men <20yr, sclerotic halo on XR
• osteosarcoma: malignant, affects metaphyses, bimodal age distribution. XR signs include Codman triangle (lifting of periosteum) and sunburst appearance
• Ewing’s sarcoma: malignant, affecting mesenchymal and neuroectodermal cells. occurs due to t11:22. affects young males. XR shows onion skin appearance
• giant cell tumour: either benign or malignant. multi-nucleated osteoclasts. soap-bubble appearance on XR.
• chondrosarcoma: malignant tumour of cartilage. affects older patients (>45). moth-eaten cloth appearance on XR.
• fibrosarcoma: malignant, affects abnormal bone (fibrous dysplasia of infarct etc.). affects young patients and shows a Shepard’s crook deformity on XR.

Question 38

22. Osteoarthritis (OA): pathology, clinical features, investigations, x-ray findings, management.

Answer 38

• pathology: degeneration of cartilage resulting in structural and functional failure of synovial joints. In 95% it is due to aging (‘wear and tear’) but may also occur due to trauma, diabetes, or obesity.
• clinical features: typically the patient is >50yr and has only one or a few joints affected. symptoms include deep, insidious achy pain that worsens with use, morning stiffness, and limitation of movement. clinical signs include crepitus, restricted movement, bony enlargement, joint effusion or inflammation, and bone instability.
• Ix: raised ESR/CRP (inflammatory markers) but RA markers are negative (e.g. ANAs and RF). MRI may show mensical tears and cartilage injury
• XR findings [LOSS]: loss of joint space, osteophytes, subarticular sclerosis, subchondral cysts. XR findings may not correlate with clinical symptoms. diagnosis may be made without XR but are useful in confirming.
• Mx: lifestyle (losing weight, support), physical measures (local heat, ice packs, massage, topical NSAIDs). analgesia follows the ladder: oral paracetamol/topical NSAIDs –> oral NSAIDs (consider adding a PPI) –> short term opiate use. steroid injection may be useful. in severe cases, treatment is with replacement arthroscopy.

Question 39

23a. Rheumatoid arthritis (RA): pathogenesis, antibodies, clinical features, scoring systems, investigations, complications

Answer 39

• pathogenesis: non-suppurative proliferative and inflammatory response of the joints and other body systems. CD4+ cells are exposed to a trigger and when exposed again release cytokines that cause the disease; most important are IFNy, IL-1 and -17, TNF, and RANKL. There are five main histological stages:
  – synovial cell hyperplasia
  – dense inflammatory infiltrates
  – angiogenesis
  – fibrinopurulent exudate
  – erosions and subcondral cysts (caused by OCs).
  – together these form a pannus, which then bridges the synovium to form a fibrous ankylosis.
• antibodies:
  – anti-CCP (anti-citrullinated peptides) occur where arginine is post-translationally modified to be replaced by citrulline, which is then recognised by CD4 cells.
  – RF (rheumatoid factor) is IgM/IgA directed against the Fc portion of patient’s own IgG antibodies
• clinical features: malaise, fatigue, and general MSK pain and peripheral polyarthritis.
  – hands and wrists: ulnar drift, palmar subluxation, fingers (swan-neck, boutonniere deformities)
  – shoulders: may mimic rotator cuff tendonitis or painful arc syndrome
  – knees: synovitis, knee effusion (responds well to aspiration and steroids), valgus or varus deformity, Baker (popliteal) cysts)
  – feet: swelling of MTP joints, ulcers, calluses, flat medial arch, valgus ankle
  – TMJ, acromioclavicular, sternoclavicular, cricoarytenoid joint dysfunction
  – extra-articular: subcutaneous nodules,, vasculitis, lung fibrosis, pericarditis, endocarditis, episcleritis, scleritis, nephrotic syndrome, CKD, amyloid, Felty syndrome, anaemia
• scoring systems: ACR and DAS28. ACR based on number of joints involved (>10 = 5), serology (high titre = 3), acute phase reactants (CRP/ESR = 1), and duration (>6wk = 1). DAS28 used to measure disease progression.
• complications: septic arthritis (most commonly s aureus), amyloidosis, carpal tunnel, subcutaneous nodules.

Question 40

23b. Rheumatoid arthritis (RA): management.

Answer 40

• Mx: DMARD + short course prednisolone as bridging therapy, and monitor response with CRP/DAS28 score. DMARDs: MOA and s/e:
  – MTX: inhibits dihydrofolate reductase. s/e include teratogenicity, TB reactivation, agranulocytosis, and folic acid antagonism
  – sulfasalazine: inhibits prostaglandins, broken down by GI flora to 5-ASA. s/e include leucocytopenia, thrombocytopaenia; safe in pregnancy.
  – HCQ: interferes with lysosome activity and autophagy. s/e include irreversible retinopathy
  – leflunomide: inhibits DHODH preventing synthesis of rUMP. s/e are diarrhoea and long-half life (avoid if family planning).
  – biologics include anti-TNFs (etanercept, infliximab, adalimumab), anti-CD20 (rituximab), and T-cell modulation (abatacept). s/e of anti-TNFs include cardiac failure, TB reactivation, and amyloidosis.

Question 41

24a. Seronegative spondyloarthropathies: ankylosing spondylitis (AS): clinical features, diagnostic criteria, investigation, management.

Answer 41

• clinical features: lower back pain and spinal immobility most common in young men. fusion of apophyseal joints may cause a ‘bamboo spine’ or ‘question mark spine’ on imaging. pain is worse at night and improves with movement.
• diagnostic criteria: 4/5 of the following has a 80% sensitivity for AS.
  – age <45
  – insidious onset
  – improvement of back pain with exercise
  – no improvement of back pain with rest
  – pain at night with improvement on getting up
• Ix: Schober’s test (less than 20cm expansion on flexion of the spine). others include inflammatory markers (ESR/CRP), HLA-B27, XR (sacroiliac joint definition loss and sclerosis), and MRI to detect early changes.
• Mx: NSAIDs, steroids during flares, and anti-TNF therapy. useful to consider are physiotherapy, smoking cessation, bisphosphonates for osteoporosis, and spinal surgery.

Question 42

24b. Seronegative spondyloarthropathies: reactive arthritis: pathology, presentation, management.

Answer 42

• pathology: reactive arthritis is a sterile arthritis that occurs after infection of the GU (chlamydia, gonorrhoea) or GI (shigella, salmonella, campylobacter) tracts. it occurs in the lower limbs a few days to weeks after presentation.
• presentation [can’t see, can’t pee, can’t climb a tree]: conjunctivitis, circinate balanitis, arthritis.
• Mx: joint should be considered septic until proven otherwise. aspirate and provide abx cover until culture and gram stain performed. Mx of reactive arthritis is with steroid injection and DMARDs in chronic cases.

Question 43

24c. Seronegative spondyloarthropathies: psoriatic arthritis: clinical features, management

Answer 43

• clinical features: within 10yr of onset of psoriasis. 30% of those diagnosed with psoriasis will develop PsA.
• presents as a mono- or asymmetrical oligoarthritis, sacroilitis, DIP swelling with nail changes (nail dystrophy, onycholysis, dactylitis). XR may show pencil-in-cup appearance.
• Mx: NSAIDs, local steroid injection, DMARDs. avoid HCQ avoided as it causes flare ups of psoriasis.

Question 44

25. Septic arthritis: microbiology, presentation, investigation and management.

Answer 44

• microbiology: H influenzae (<2yr), S aureus (>2yr), N gonorrhoea (sexually active young adults), Salmonella (sickle cell)
• presentation: sudden inflammation of a joint with limited ROM, held immobile by muscle spasm. most cases only involve one joint.
• Ix: arthrocentesis and gram stain, blood culture, leucocytosis, skin swab, throat or sputum swab, or urinalysis.
• Mx: begin before culture results are available. immobilise the joint and give IV flucloxacillin and oral sodium fusidate (allergy: erythromycin or clindamycin).
  – if a prosthesis is involved, it should be removed and replaced with an antibiotic-impregnated space for 3-6wk before replacing the prosthesis. cover with teicoplanin and sodium fusidate.

Question 45

26. Gout: pathology, risk factors, presentation, investigation, management.

Answer 45

• pathology: crystal induced arthritis, caused by monosodium urate (uric acid) within and around joints. deposition of uric acid in the joints triggers the immune response, particularly IL-1 and proteases.
• Rx: male, genetic predisposition, heavy alcohol consumption (esp. beer, rich in purines), obesity, thiazide diuretics and aspirin.
• presentation: the first MTP is the most common joint affected (‘podagra’), with extreme pain and effusion into the joint.
• Ix: arthrocentesis (negatively refringent of polarised light), serum uric acid, urea and creatinine (for eGFR)
• Mx: responds rapidly to painkillers (NSAIDs or colchicine if NSAIDs C/I). first line prevention of further attacks is lifestyle modification (reduce alcohol, cholesterol, lose weight etc.). allopurinol, a xanthine oxidase inhibitor, should be used when attacks are severe and frequent. it must never be taken during an acute attack, but may be continued through attacks if started before.

Question 46

27. Ehlers-Danlos syndrome: pathology, presentation, diagnosis, management.

Answer 46

• pathology: autosomal dominant. many different types, with ED type III most common (hypermobility). affects type III collagen which produces reticular fibres supporting soft organs.
• presentation: most suffer no adverse effects. can cause recurrent subluxation, widespread MSK pain. cutaneous features include hyperextensive skin, tissue paper scarring, and pseudotumours. internal features can include rupture of colon and large arteries, ocular fracture and retinal detachment, and diaphragmatic hernia.
• Dx: clinical diagnosis, with examination of joints and skin, and DNA studies for specific mutation if possible.
• Mx: supportive, e.g. physiotherapy, orthopaedic instruments, beta-blockade

Question 47

28. Osteogenesis imperfecta (OI): pathology, presentation, types of OI, and management.

Answer 47

• pathology: deficiency in collagen I synthesis (forms most bone). most cases are autosomal dominant. bones tend to be gracile with thin cortices and osteopenia.
• presentation: multiple fragility fractures in childhood, short stature, blue sclerae (high yield), and loss of hearing. may be mistaken for NAI
• types:
  – I: mild deformities, hypermobility of joints and heart valve disorders
  – II: death in the prenatal period
  – III: severe bone deformity
  – IV: fewer fractures, normal sclerae, normal lifespan.
• Mx: daily oral risedronate. prognosis is variable, depending on severity of the disease

Question 48

29. MSK tumours and cysts: ganglion, synovial cyst, tenosynovial giant cell tumour, bursitis

Answer 48

• ganglion: small cyst near a joint capsule or tendon sheath. most commonly at wrist. well-defined, firm, and readily transilluminate
• synovial cyst: herniation of synovium through a joint capsule or enlargement of a bursa. most-common is the Baker cyst seen in RA.
• tenosynovial giant cell tumour: develops in synovial lining of joints, tendon sheaths, and bursae. two main types: diffuse (large joints) and localised (small joints). arises from t1:2 which stimulates macrophages from over-expression of M-CSF. therefore, anti-M-CSF looks promising in treatment.
• bursitis: inflammation of the bursa; small fluid filled sacs around synovium to protect from friction. excision may be required with recurrent cases.

Question 49

30a. Systemic lupus erythematosus (SLE): pathology, auto-antibodies

Answer 49

• pathology: type III hypersensitivity involving multiple organs, orchestrated by ANAs. immunologic factors include failure of self-tolerance of B cells and CD4+ cells (specific for the nucleosome), toll-like receptor engagement, and presence of type I interferons. environmental factors such as UV light, female sex, EBV, and drugs (hydralazine, procainamide, and penicillamine) have also been implicated. complement is consumed in immune complexes.
• auto-antibodies:
  – ANA: highly sensitive (rule-out test)
  – anti-dsDNA: highly specific (rule-in)
  – anti-Smith: highly specific
  – anti-RNP
  – anti-Ro (SS-A): common in subcutaneous, neonatal lupus, congenital heart block, decreased risk of nephritis
  – anti-La (SS-B): decreased risk of nephritis

Question 50

30b. Systemic lupus erythematosus: clinical presentation and diagnosis.

Answer 50

• presentation:
  – blood vessels (100%). necrotizing vasculitis, anaemia, thrombocytopenia
  – renal (50-70%). six classes of lupus nephritis depending on how much of the kidney is involved
  – skin (85%): facial butterfly rash, urticaria, bullae, livedo reticularis, photosensitivity, Raynaud’s
  – joints (80-90%). synovitis which is typically painful but not swollen. myalgia.
  – CNS (25-35%): neuropsychiatric features
  – cardiovascular (25%): pericarditis, aortic or mitral valve disease, Libman-Sacks endocarditis
  – pulmonary (45%): pleuritis, interstitial fibrosis, pulmonary hypertension
  – ocular (15%): episcleritis, conjunctivitis, optic neuritis, secondary Sjogren’s
  – GI: mouth ulcers, small bowel infarct or perforation, liver or pancreas involvement (rare)
  – systemic (55-100%): fever, fatigue, weight loss.
• Ix: leucopenia, lymphopenia, thrombocytopenia, anaemia (haemolytic), raised ESR (typically normal CRP), low serum albumin (high urinary ALB/CR ratio), screen for autoantibodies and quantify compliment. CT chest may be useful for fibrosis or effusion.

Question 51

30c. Systemic lupus erythematosus (SLE): management

Answer 51

• general: lifestyle, avoidance of excessive sunlight (due to photosensitivity), reduce cardiovascular risk factors. NSAIDs and topical steroids work well for cutaneous features.
• pharmacologic: HCQ is the treatment of choice for SLE; regular eye checks are required due to the s.e of retinal toxicity. consider cyclophosphamide or prednisolone with internal organ involvement.

Question 52

31. Sjogren syndrome: pathology, presentation, investigations, diagnosis, management

Answer 52

• pathology: lymphocytic destruction of the salivary and lacrimal glands. triggers are thought to include HTLV, HIV, and HCV. about 75% are positive for RF, and anti-Ro and anti-La in about 90%.
• presentation: most common in women 50-60yr. ocular symptoms include blurred vision, burning, itching, and accumulation of thick secretions in the conjunctival sac. parotid symptoms include dysphagia, decreased taste, cracks and fissures in the mouth, and dryness of the buccal mucosa. other complications include pulmonary fibrosis, bronchitis, pneumonitis, and synovitis.
• Ix: biopsy of lip, Schirmer tear test, labe test (raised Ig, immune complexes, anti-Ro and anti-La).
• Dx: 4+ of the following indicates the diagnosis:
  – dry eyes >3m
  – dry mouth, swollen glands
  – Schirmer’s positive
  – abnormal sialography
  – positive lip biopsy
  – positive anti-Ro or -La
• Mx: artificial tears and saliva replacement solution. pilocarpine, HCQ, and steroids may be helpful to consider.

Question 53

32. Systemic sclerosis: classification and pathology, presentation, investigations, management.

Answer 53

• classification and pathology: two types - diffuse (30%) and limited (70%). limited is also known as CREST syndrome: calcinosis, Raynaud’s, eosophageal dysmotility, sclerodactyly, and telangiectasia. pathology is uncertain, but is known to be autoimmune based and involves anti-Scl 70 (diffuse) and anti-centrometre (limited/CREST).
• presentation:
  – skin: fingers become tapered and claw-like with loss of movement. atrophy of skin occurs
  – GI: atrophy and fibrosis of smooth muscle, most commonly in the lower oesophagus (causing dysmotility).
  – MSK: synovial inflammation and fibrosis
  – renal: hypertension caused by renal fibrosis
  – lungs: pulmonary hypertension and fibrosis
  – heart: pericarditis, effusion, fibrosis, arrhythmia from fibrosis
• Ix: FBC (normocytic anaemia), U&Es, eGFR (raised urea and creatinine), autoantibodies (anti-centromere, anti-Scl 70, RF, ANA)
• Mx: there is no cure, so Mx should be organ-based. Raynaud’s should be treated with CCBs, ACE inhibitors, ARBs etc.

Question 54

33. Anti-phospholipid syndrome (APLS): presentation, investigation, management, APLS in pregnancy

Answer 54

• presentation: thrombosis (arterial or venous, e.g. stroke or DVT), recurrent miscarriage, and positive antibodies (anticardiolipin, lupus anticoagulant, anti-B2 glycoprotein I). additional features include thrombocytopaenia, chorea, migraine, epilepsy, valvular heart disease, livedo reticularis, and renal impairment.
• Ix: persistently positive antibodies (positive on 2+ occasions <12wk apart). FBC to show thrombocytopaenia. Direct Coombs’ test to show haemolytic anaemia.
• Mx: long-term anticoagulation with warfarin with low target INR (2-3 for initial, 3-4 for recurrent).
• pregnancy: oral aspirin and LMWH from when a foetal heart is seen on USS, and LMWH discontinued at 34wk. Increases live birth rate seven-fold.

Question 55

34. Dermatomyositis and polymyositis: pathology, presentation, investigations, management

Answer 55

• pathology: autoimmune disease involving Anti-Mi2, anti-Jo1, and anti-P155/P140. complement consumption is more associated with dermatomyositis, while CD8+ cells are more associated with polymyositis.
• presentation: insidious proximal muscle weakness, myalgia, malaise, weight loss. may present with difficulty e.g. rising from a chair, climbing stairs etc. DM includes heliotrope rash (eyelids) and Gottron papules. organ involvement is a late stage of these diseases.
• Ix: raised CK (muscle necrosis), ALT/AST, LDH, ERP/CRP. autoantibodies may be positive. electromyography.
• Mx: prednisolone until 1 month after remission; then steroid sparing agents (AZA, MTX, CYC). Rituximab may be more useful in auto-antibody positive cases.

Question 56

35. Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR): pathology, presentation, investigations, management.

Answer 56

• pathology: large-vessel vasculitis principally affecting the temporal and ophthalmic arteries. seems to be related to a T-cell response (TNF, anti-endothelial and anti-smooth muscle cell antibodies).
• presentation: almost always >50. may be vague and constitutional, tenderness of the scalp, claudication on eating. PMR is strongly related to GCA and presents with sudden pain and stiffness in the shoulders and neck, and hips and lumbar spine. ophthalmic features of GCA may include amaurosis fugax and posterior ciliary artery infarct (causing blindness).
• Ix: long biopsy (1+cm) of the temporal artery; negative result does not exclude the disease. also include ESR/CRP, ALP/GGT, anaemia (normocytic).
• Mx: tapered dose of steroids for 12-18 months. steroid-sparing agents in refractory cases.

Question 57

36. Takayasu arteritis: pathology, presentation, management.

Answer 57

• pathology: medium-large vessel arteritis with granulomas. particularly affects the aorta, causing transmural fibrous thickening.
• presentation: hypertension, absent pulses in upper extremities, claudication of legs, pulmonary hypertension, MI (coronary arteries), systemic hypertension (renal arteries).
• Mx: steroids

Question 58

37. Polyarthritis nodosa (PAN): pathology, presentation, investigations, management

Answer 58

• pathology: medium sized vessel vasculitis. inflammation is segmental transmural necrotizing. there is a strong link with hepatitis B and pANCA antibodies.
• presentation:
  – constitutional: fever, malaise, arthralgia, weight loss
  – neuro: mononeuritis multiplex, sensorimotor polyneuropathy
  – abdo: pain
  – renal: haematuria, proteinuria, renal failure, hypertension
  – cardiac: MI, CHF, pericarditis
  – skin (livedo reticularis)
• Ix: bloods (anaemia, leucocytosis, raised ESR), angiography (microaneurysm in hepatic, intestinal, or renal arteries), antibodies (HBV 30%, pANCA 20%), and other Ix as appropriate (e.g. ECG, abdo USS etc.)
• Mx: immunosuppression: steroids or steroid sparing agents (e.g. AZA, MTX).

Question 59

38. Kawasaki disease: pathology, presentation, investigation, management.

Answer 59

• pathology: vasculitis affecting the coronary arteries primarily in children <4. vascular disease is primarily mediated by T cells and macrophages.
• presentation: fever >5 days resistant to antipyretics, red palms and soles which peel ~5days after onset, bright red cracked lips, strawberry tongue, cervical lymphadenopathy.
• Ix: FBC (leucocytosis, thrombocytosis, raised CRP), echo (instead of angiography for coronary artery aneurysm)
• Mx: single high-dose IVIg, plus high dose aspirin daily (normally C/I in children due to risk of Reye’s syndrome)

Question 60

39. ANCA-associated vasculitis: risk factors, ANCA-positivity, URT symptoms, LRT symptoms, renal symptoms, other clinical features, and general management

Answer 60

• three main ANCA-related vasculitidies: granulomatosis with polyangiitis (GPA, previous Wegener’s); eosinophilic GPA (EGPA, previous Churg-Strauss), and microscopic polyangiitis (MPA).
• GPA:
  – granulomas present
  – risks: ???
  – ANCA-positivity: cANCA [PR3-ANCA]
  – URT: epistaxis, sinusitis, nasal crusting
  – LRT: dyspnoea, haemoptysis
  – renal: rapidly progressive glomerulonephritis
  – other: proptosis, CN lesions
• EGPA:
  – granulomas present
  – risks: leukotriene receptor antagonists
  – ANCA-positivity: pANCA [MPO-ANCA]
  – URT: paranasal sinusitis
  – LRT: late onset asthma
  – renal: N/A
  – other: eosinophilia, polyneuropathy (mononeuritis multiplex),
• MPA:
  – risks: penicillin, strep, tumours
  – ANCA-positivity: pANCA [MPO-ANCA]
  – URT: N/A
  – LRT: cough, dyspnoea, haemoptysis
  – renal: raised creatinine, proteinuria, haematuria
  – other: systemic (fever, lethargy, myalgia, weight loss), polyneuropathy (mononeuritis monoplex)
• Mx: depends on the organs involved. major organ involvement (particularly with GPA) requires high-dose steroids, immunosuppression, and sometimes plasma exchange.

Question 61

40. Trauma: the Glasgow Coma Scale (GCS).

Answer 61

• three sections (motor, verbal, and eye opening) with a maximum score of 15 and a minimum of 3.
• motor: obeys commands (6), localises pain (5), normal withdrawal (flexion, 4), abnormal withdrawal (3), extension (2), and none (1)
• verbal: orientated (5), confused conversation (4), inappropriate words (3), incomprehensible sounds (2), none (1)
• eye opening: spontaneous (4), to speech (3), to pain (2), to none (1)

Question 62

41. Trauma: fractures - definition and pathology, types, open vs closed, investigation, management

Answer 62

• definition and pathology: break in the bone due to direct / indirect trauma (direct blow, twisting or bending) or pathological (abnormal bone which fractures on minimal trauma).
• types: five basic types: transverse, oblique (shearing force), spiral (torsional force), comminuted (3+ fragments, very unstable), segmental (fracture in two separate places)
• open vs closed: Gustilo and Anderson system:
  – 1. low energy <1cm
  – 2. moderate soft tissue damage >1cm
  – 3. high energy, extensive soft tissue damage >1cm
  — 3a. adequate soft tissue coverage
  — 3b. inadequate soft tissue coverage
  — 3c. associated arterial injury
• Ix: XR is used to diagnose most with usually both an AP and lateral view. CT can be used for complex bones (vertebrae, pelvis, calcaneus, glenoid etc.). MRI is useful when fracture is suspected but XR is normal.

Question 63

42. Trauma: nerve injury: types, common specific injuries

Answer 63

• neurapraxia: temporary conduction defect from compression or stretch, resolves fully over time (<28 days)
• axonotmesis: sustained compression or stretch, or high degree of force. endoneurium remains intact but axons undergo Wallerian degeneration. regenerates about 1mm per day. recovery is variable.
• neurotmesis: complete transection of a nerve. occur in penetrating injuries. observation for recovery is all that is usually required.
• common specific injuries:
  – Colles #: carpal tunnel
  – anterior dislocation of shoulder: axillary nerve
  – humeral shaft #: radial nerve
  – supracondylar fracture of elbow: median nerve
  – lateral knee, foot drop: common peroneal nerve

Question 64

43. Trauma: compartment syndrome - pathology, causes, presentation, investigations, managament.

Answer 64

• pathology: rise in pressure in compartments of the limbs causes hypoxia and tissue damage. in response to compression of arteries, cells release histamine, nitric oxide causing extracellular oedema. lack of ATP causes lower function of the Na/K ATP pump, causing hyponatraemia and oedema
• causes: bleeding (e.g. penetrating wounds), swelling (e.g. severe burns), crush injury, inappropriate cast placement, and reperfusion injury
• presentation [6 Ps]: pain, paraesthesia, pulselessness, pallor, poikilothermic, paralysis. the first two are the most common.
• Ix: physical exam (showing pain worsening with passive stretching, and wood-like stiff muscles), bloods (creatinine kinase, myoglobin), intra-compartmental pressure monitoring, imaging
• Mx: surgical (fasciotomy).