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 measured in degrees.

• Rotation is measured in degrees along the longitudinal axis of

the bone, e.g. for spiral fracture of the tibia or phalanges.

• Shortening: proximal migration of the distal fragment can cause

shortening in an oblique fracture. Shortening may also occur if

there has been impaction at the fracture site, e.g. a Colles’

fracture of the distal radius.

• Is there distal nerve or vascular deficit?

• What is the state of the tissues associated with the fracture (soft

tissues and joints, e.g. fracture blisters, dislocation)?

13.20 Common musculoskeletal investigations

Investigation Indication/comment

Urinalysis

Protein Glomerular disease, e.g. SLE, vasculitis

Secondary amyloid in RA and other chronic arthropathies

Drug adverse effects, e.g. myocrisin, penicillamine

Blood Glomerular disease, e.g. SLE, vasculitis

Haematological

Full blood count Anaemia in inflammatory arthritis, blood loss after trauma

Neutrophilia in sepsis and very acute inflammation, e.g. acute gout

Leucopenia in SLE, Felty’s syndrome and adverse effects of antirheumatic drug therapy

Erythrocyte sedimentation rate/plasma viscosity Non-specific indicator of inflammation or sepsis

C-reactive protein Acute-phase protein

Biochemical

Urea and creatinine ↑ in renal impairment, e.g. secondary amyloid in RA or adverse drug effect

Uric acid May be ↑ in gout. Levels may be normal during an acute attack

Calcium ↓ in osteomalacia; normal in osteoporosis

Alkaline phosphatase ↑ in Paget’s disease, metastases, osteomalacia and immediately after fractures

Angiotensin-converting enzyme ↑ in sarcoidosis

Urinary albumin : creatinine ratio Glomerular disease, e.g. vasculitis, SLE

Serological

Immunoglobulin M rheumatoid factor ↑ titres in 60–70% of cases of RA; occasionally, low titres in other connective diseases. Present

in up to 15% of normal population. Superseded by anti-cyclic citrullinated peptide antibodies

Anti-cyclic citrullinated peptide antibody (ACPA) Present in 60–70% of cases of RA and up to 10 years before onset of disease. Highly specific for

RA. Occasionally found in Sjögren’s syndrome

Antinuclear factors ↑ titres in most cases of SLE; low titres in other connective tissue diseases and RA

Anti-Ro, Anti-La Sjögren’s syndrome

Investigations

Common investigations in patients with musculoskeletal disease

are summarised in Box 13.20.

Investigations • 281

13

13.20 Common musculoskeletal investigations – cont’d

Investigation Indication/comment

Anti-double-stranded DNA SLE

Anti-Sm SLE

Anti-ribonucleoprotein Mixed connective tissue disease

Antineutrophil cytoplasmic antibodies Granulomatosis with polyangiitis, polyarteritis nodosa, Churg–Strauss vasculitis

Other

Schirmer tear test, salivary flow test Keratoconjunctivitis sicca (dry eyes), Sjögren’s syndrome

Imaging

Plain radiography (X-ray) Fractures, erosions in RA and psoriatic arthritis, osteophytes and joint-space loss in osteoarthritis,

bone changes in Paget’s disease, pseudofractures (Looser’s zones) in osteomalacia

Ultrasonography Detection of effusion, synovitis, cartilage breaks, enthesitis and erosions in inflammatory arthritis.

Double contour sign in gout

Detection of bursae, tendon pathology and osteophytes

Magnetic resonance imaging Joint and bone structure; soft-tissue imaging

Computed tomography High-resolution scans of thorax for pulmonary fibrosis

Dual-energy X-ray absorptiometry Gold standard for determining osteoporosis. Usual scans are of lumbar spine, hip and lateral

vertebral assessment for fractures

Isotope bone scan Increased uptake in Paget’s disease, bone tumour, infection, fracture. Infrequently used due to

high radiation dose.

Joint aspiration/biopsy

Synovial fluid microscopy Inflammatory cells, e.g. ↑ neutrophils in bacterial infection

Polarised light microscopy Positively birefringent rhomboidal crystals – calcium pyrophosphate (pseudogout)

Negatively birefringent needle-shaped crystals – monosodium urate monohydrate (gout)

Bacteriological culture Organism may be isolated from synovial aspirates

Biopsy and histology Synovitis – RA and other inflammatory arthritides

RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.

OSCE example 1: Right shoulder pain

Mr Hunt, 38 years old, has a 2-month history of right shoulder pain with no history of trauma.

Please examine the shoulder

• Introduce yourself and clean your hands.

• Expose both of the patient’s shoulders and arms.

• Comment on acromioclavicular deformity and muscle wasting; look for winging of the scapula.

• Compare the right shoulder to the normal left shoulder.

• Perform active and passive movements. In particular, look for frozen shoulder, which is diagnosed by limitation of external rotation and flexion.

• Finally, examine the arm, looking for conditions such as biceps rupture.

• If all movements of the shoulder are normal, conduct a full examination of the neck.

• Thank the patient and clean your hands.

Summarise your findings

The patient reports pain between 120 and 60 degrees of abduction when lowering the abducted shoulder. Pain is reproduced on abduction against

resistance.

Suggest a differential diagnosis

The most common cause of these symptoms is impingement syndrome, which can be confirmed by carrying out special tests (Neer and Hawkins–

Kennedy). Differentials include frozen shoulder, calcific tendonitis, acromioclavicular joint pain, arthritis (osteoarthritis, rheumatoid arthritis or

post-traumatic), long head of biceps rupture and referred pain from the neck.

Suggested investigations

X-ray will reveal degenerative changes in osteoarthritis or tendon calcification. Ultrasound may demonstrate effusions, calcific deposits and tendon

damage/rupture.

282 • The musculoskeletal system

OSCE example 2: Painful hands

Mrs Hill, 46 years old, presents with an 8-week history of insidious onset of pain, stiffness and swelling of her hands. She smokes 15 cigarettes per day.

Please examine her hands

• Introduce yourself and clean your hands.

• Look:

• In this case there is swelling of two MCP joints on the right, and one PIP joint on the left.

• Normal nails and skin (therefore psoriatic arthropathy is unlikely).

• Feel:

• Ask first what is sore and seek permission to examine gently.

• Tender, soft swelling of the MCP and PIP joints in the hands and left elbow.

• In feet: tender across her MTP joints on squeeze test but no palpable swelling.

• Move:

• Painful MCP joints in right hand on active and passive flexion, reducing handgrip and fine movements.

Summarise your findings

The patient has tender, soft swelling of two MCP joints and one PIP joint. There is pain on active and passive movement of the affected joints, resulting

in limitation of hand function.

Suggest a differential diagnosis

The pattern of joint involvement, patient’s gender, duration of symptoms and history of smoking support a clinical diagnosis of rheumatoid arthritis. The

differential diagnosis of psoriatic arthropathy is less likely because of her normal nails and lack of the typical skin changes of psoriasis.

Suggest initial investigations

Full blood count, renal function tests, calcium, phosphate and liver function tests to assess for anaemia of chronic disease and to determine suitability

for disease-modifying antirheumatic drugs; C-reactive protein to assess the degree of systemic inflammation; anti-CCP antibody to confirm whether

seropositive rheumatoid arthritis is present; application of the 2010 American College of Rheumatology/European League Against Rheumatism criteria

(see Box 13.14) for classification of rheumatoid arthritis; hand and foot X-rays to detect any bony erosions; chest X-ray to look for rheumatoid lung

disease.

Integrated examination sequence for the locomotor system

• Ask the patient to undress to their underwear.

• Ask the GALS (gait, arms, legs, spine) questions and perform the GALS screen.

• Identify which joints require more detailed examination:

• What is the pattern of joint involvement?

• Is it likely to be inflammatory or degenerative?

• Examine gait and spine in more detail first, if appropriate, then position the patient on the couch for detailed joint examination.

• Assess the general appearance:

• Look for pallor, rashes, skin tightness, evidence of weight or muscle loss, obvious deformities.

• Check the surroundings for a temperature chart, walking aids and splints, if appropriate.

• Examine the relevant joint, or all joints if systemic disease suspected:

• Ask about tenderness before examining the patient.

• Look at the skin, nails, subcutaneous tissues, muscles and bony outlines.

• Feel for warmth, swelling, tenderness, and reducibility of deformities.

• Move:

– Active movements first: demonstrate to the patient then ask them to perform the movements. Is there pain or crepitus on movement?

– Passive movements second: determine the patient’s range of movement. Measure with a goniometer. What is the end-feel like? Describe the

deformities.

• If systemic disease is suspected, go on to examine all other systems fully.

• Consider what investigations are required:

• Basic blood tests.

• Inflammatory markers.

• Immunology.

• Ultrasound.

• X-rays.

• Special tests.

• Joint aspiration for synovial fluid analysis or culture.

14

The skin, hair and nails

Michael J Tidman

Anatomy and physiology 284

Skin 284

Hair 285

Nails 285

The history 285

Common presenting symptoms 285

Past medical and drug history 285

Family and social history 286

The physical examination 286

Distribution of a rash 286

Morphology of a rash 286

Morphology of lesions 290

Hair and nail signs 290

Supplementary examination techniques 291

Investigations 292

OSCE example 1: Pruritus 292

OSCE example 2: Pigmented lesion 293

Integrated examination sequence for the skin 293

284 • The skin, hair and nails

Dermatological conditions are very common (10–15% of general

practice consultations) and present to doctors in all specialties.

In the UK, 50% are lesions (‘lumps and bumps’), including skin

cancers, and most of the remainder are acute and chronic

inflammatory disorders (‘rashes’), including infections, with genetic

conditions accounting for a small minority.

Dermatological diagnosis can be challenging: not only is there a

vast number of distinct skin diseases, but also each may present

with a great variety of morphologies and patterns determined by

intrinsic genetic factors, with the diagnostic waters muddied still

further by external influences such as rubbing and scratching,

infection, and well-meaning attempts at topical and systemic

treatment. Even in one individual, lesions with the same pathology

can have a very variable appearance (for example, melanocytic

naevi, seborrhoeic keratoses and basal cell carcinomas).

Many skin findings will have no medical significance, but it is

important to be able to examine the skin properly in order to

identify tumours and rashes, and also to recognise cutaneous

signs of underlying systemic conditions. The adage that the skin

is a window into the inner workings of the body is entirely true,

and an examination of the integument will often provide the

discerning clinician with important clues about internal disease

processes, as well as with information about the physical and

psychological wellbeing of an individual.

Anatomy and physiology

Skin

The skin is the largest of the human organs, with a complex

anatomy (Fig. 14.1) and a number of essential functions

(Box 14.1). It has three layers, the most superficial of which

is the epidermis, a stratified squamous epithelium, containing

melanocytes (pigment-producing cells) within its basal layer, and

Langerhans cells (antigen-presenting immune cells) throughout.

The dermis is the middle and most anatomically complex layer,

containing vascular channels, sensory nerve endings, numerous

cell types (including fibroblasts, macrophages, adipocytes and

smooth muscle), hair follicles and glandular structures (eccrine,

sebaceous and apocrine), all enmeshed in collagen and elastic

tissue within a matrix comprising glycosaminoglycan, proteoglycan

and glycoprotein.

The deep subcutis contains adipose and connective tissue.

Dermatoses (diseases of the skin) may affect all three

layers and, to a greater or lesser extent, the various functions

of the skin.

Fig. 14.1 Structures of the skin.

Epidermis

Dermis

Subcutis

Shaft of hair

Opening of sweat duct

Sweat duct

Subpapillary vascular plexus

Sebaceous gland

Arrector pili muscle

Sweat gland

Hair follicle

Subcutaneous adipose tissue

Deep cutaneous vascular plexus

Muscle layer

14.1 Functions of the skin

• Protection against physical injury and injurious substances, including

ultraviolet radiation

• Anatomical barrier against pathogens

• Immunological defence

• Retention of moisture

• Thermoregulation

• Calorie reserve

• Appreciation of sensation (touch, temperature, pain)

• Vitamin D production

• Absorption – particularly fetal and neonatal skin

• Psychosexual and social interaction

The history • 285

14

Hair

Hair plays a role in the protective, thermoregulatory and sensory

functions of skin, and also in psychosexual and social interactions.

There are two main types of hair in adults:

vellus hair, which is short and fine, and covers most of the

body surface

terminal hair, which is longer and thicker, and is found on

trunk and limbs, as well as scalp, eyebrows, eyelashes,

and pubic, axillary and beard areas.

Abnormalities in hair distribution can occur when there is

transitioning between vellus and terminal hair types (for example,

hirsutism in women) or vice versa (androgenic alopecia). Hairs

undergo regular asynchronous cycles of growth and thus, in

health, mass shedding of hair is unusual. Hair loss can occur as a

result of disorders of hair cycling, conditions resulting in damage

to hair follicles (such as purposeful removal in trichotillomania),

or structural (fragile) hair disorders.

Nails

The nail is a plate of densely packed, hardened, keratinised cells

produced by the nail matrix. It serves to protect the fingertip

and aid grasp and fingertip sensitivity. The white lunula at the

base of the nail is the visible distal aspect of the nail matrix (Fig.

14.2). Fingernail regrowth takes approximately 6 months, and

toenail regrowth 12–18 months.

The history

The possible diagnoses in dermatological conditions are broad

and some diseases have pathognomonic features. Thus, in order

to ensure that your history taking is focused and relevant, it

may be appropriate to ask to glimpse the lesion or rash before

embarking on detailed enquiry.

Common presenting symptoms

These include:

a rash: scaly, blistering or itchy

a lump or lesion

pruritus (itch)

hair loss or excess hair (hirsutism, hypertrichosis)

nail changes.

Ask:

When did the lesion appear or the rash begin?

Where is the rash/lesion?

Has the rash spread, or the lesion changed, since its

onset?

Is the lesion tender or painful? Is the rash itchy? Is the itch

intense enough to cause bleeding by scratching or to

disturb sleep, as in atopic eczema and lichen simplex? Are

there blisters?

Do the symptoms vary with time? For example, the

pruritus of scabies is usually worse at night, and acne

and atopic eczema may show a premenstrual

exacerbation.

Were there any preceding symptoms, such as a

sore throat in psoriasis, a severe illness in telogen

effluvium, or a new oral medication in drug

eruptions?

Are there any aggravating or relieving factors? For

example, exercise or exposure to heat may precipitate

cholinergic urticaria.

What, if any, has been the effect of topical or oral

medications? Self-medication with oral antihistamines may

ameliorate urticaria, and topical glucocorticoids may help

inflammatory reactions.

Are there any associated constitutional symptoms,

such as joint pain (psoriasis), muscle pain and

weakness (dermatomyositis), fever, fatigue or

weight loss?

Very importantly, what is the impact of the rash on the

individual’s quality of life?

Past medical and drug history

Ask about general health and previous medical or skin conditions;

a history of asthma, hay fever or childhood eczema suggests

atopy. Coeliac disease is associated with dermatitis herpetiformis.

Take a full drug history, including any recent oral or topical

prescribed or over-the-counter medication. Enquire about allergies

not just to medicines but also to animals or foods.

Fig. 14.2 Structure of the nail. A Dorsal view. B Cross-section.

Distal edge of nail plate

Nail plate

Lateral nail fold

(paronychium)

Lunula

Cuticle

Eponychium

A

Hyponychium

Nail bed

Nail plate

Distal phalanx

Matrix

Proximal nail fold (paronychium)

Cuticle

B

286 • The skin, hair and nails

Family and social history

Enquire about occupation and hobbies, as exposure to chemicals

may cause contact dermatitis. If a rash consistently improves

when a patient is away from work, the possibility of industrial

dermatitis should be considered. Ask about alcohol consumption

and confirm smoking status.

Document foreign travel and sun exposure if actinic damage,

tropical infections or photosensitive eruptions are being considered.

The risk of squamous cell and basal cell cancers increases

with total lifetime sun exposure, and intense sun exposures

leading to blistering burns are a risk factor for melanoma. The

susceptibility of an individual to sun-induced damage can be

determined by defining their skin type using the Fitzpatrick scale

(Box 14.2).

Ask about a family history of atopy and skin conditions.

The history of a skin disorder alone rarely enables a definite

diagnosis, with perhaps the occasional exception: an itchy eruption

that resembles a nettle rash, the individual components of which

last less than 24 hours, is very likely to be urticaria; and an

intensely itchy eruption that affects all body areas except the

head (in adults) and is worse in bed at night should be considered

to be scabies until proved otherwise.

The physical examination

Proper assessment of the skin involves all the human senses,

with the exception of taste. Once we have listened to the

patient’s history, we look at the rash or lesion, touch the skin,

and occasionally use our sense of smell to diagnose infection

and metabolic disorders such as trimethylaminuria (fish odour

syndrome).

Examination of the skin should be performed under conditions

of privacy in an adequately lit, warm room with, when appropriate,

a chaperone present (p. 20). The patient should ideally be

undressed to their underwear. Routinely, the hair, nails and oral

cavity (p. 187) should be examined, and the regional lymph

nodes (p. 33) palpated. Assess skin type using the Fitzpatrick

scale (Box 14.2).

In documenting the appearance of a lesion or rash, use the

correct descriptive terminology (Box 14.3); doing so often helps

crystallise the diagnostic thought processes.

Distribution of a rash

The distribution of a dermatosis can be very informative. Is the

eruption symmetrical? If so, it is likely to have a constitutional

basis, and if not, it may well have an extrinsic cause. This

golden rule has occasional exceptions (such as lichen simplex)

but holds true in the majority of instances. Its application will

almost always prevent the common misdiagnosis of ‘bilateral

cellulitis’ (bacterial infection) of the legs, which in actuality is

usually lipodermatosclerosis or varicose eczema; bacteria are

not known for their sense of symmetry!

The pattern of a rash may immediately suggest a diagnosis: for

example, the antecubital and popliteal fossae in atopic eczema

(Fig. 14.3A); the extensor limb surfaces, scalp, nails and umbilicus

in psoriasis (Fig. 14.3B); the flexural aspects of the wrists and

the oral mucous membranes in lichen planus; the scalp, alar

grooves and nasolabial folds in seborrhoeic dermatitis; and the

sparing of covered areas in photosensitive eruptions. Does the

rash follow a dermatome (as with shingles), or Langer’s lines of

skin tension (as with pityriasis rosea), or Blaschko (developmental)

lines (as with certain genetic disorders)? The localisation of an

eruption to fresh scars or tattoos may be a manifestation of

sarcoidosis, and the anatomical location may provide a clue to

diagnosis, such as the tendency of erythema nodosum, pretibial

myxoedema and necrobiosis lipoidica (Fig. 14.4) to involve

the shins.

Morphology of a rash

The morphology (shape and pattern) of a rash is equally

important. Violaceous, polygonal, flat-topped papules, topped

by a lacy patterning (Wickham striae), are typical of lichen planus

(Fig. 14.5). The Koebner (isomorphic) phenomenon, where a

dermatosis is induced by superficial epidermal injury, results in

linear configurations (Fig. 14.6A), and occurs par excellence in

14.2 Fitzpatrick scale of skin types

• Type 1: always burns, never tans

• Type 2: usually burns, tans minimally

• Type 3: sometimes burns, usually tans

• Type 4: always tans, occasionally burns

• Type 5: tans easily, rarely burns

• Type 6: never burns, permanent deep pigmentation

Fig. 14.3 Distribution of rash. A Atopic eczema localising to the

flexural aspect of the knees. B Psoriasis involving the extensor aspect of

the elbow.

A

B

The physical examination • 287

14

psoriasis, lichen planus, viral warts and molluscum contagiosum.

Linear or angular markings (erythema or scarring) raise the

likelihood of artefactual (self-inflicted) damage to the skin. The

presence of blisters limits the diagnostic possibilities to a relatively

small number of autoimmune (such as dermatitis herpetiformis,

pemphigoid (Fig. 14.6B) and pemphigus), reactive (including

14.3 Descriptive terminology

Term Definition

Abscess A collection of pus, often associated with signs

and symptoms of inflammation (includes boils and

carbuncles)

Angioedema Deep swelling (oedema) of the dermis and

subcutis

Annular Ring-like

Arcuate Curved

Atrophy Thinning of one or more layers of the skin

Blister A liquid-filled lesion (vesicles and bullae)

Bulla A large blister (>0.5 cm)

Burrow A track left by a burrowing scabies mite

Callus (callosity) A thickened area of skin that is a response to

repeated friction or pressure

Circinate Circular

Comedo A blackhead

Crust (scab) A hard, adherent surface change caused by

leakage and drying of blood, serum or pus

Cyst A fluid-filled papular lesion that fluctuates and

transilluminates

Discoid Disc-like

Ecchymosis

(bruise)

A deep bleed in the skin

Erosion A superficial loss of skin, involving the epidermis;

scarring is not normally a result

Erythema Redness of the skin that blanches on pressure

Erythroderma Any inflammatory skin disease that affects >80%

of the body surface

Exanthem A rash

Excoriation A scratch mark

Fissure A split, usually extending from the skin surface

through the epidermis to the dermis

Freckle An area of hyperpigmentation that increases in the

summer months and decreases during winter

Furuncle A boil

Gyrate Wave-like

Haematoma A swelling caused by a collection of blood

Horn A hyperkeratotic projection from the skin surface

Hyperkeratosis Thickening of the stratum corneum

Ichthyosis Very dry skin

Keratosis A lesion characterised by hyperkeratosis

Lentigo An area of fixed hyperpigmentation

Lichenification Thickening of the epidermis, resulting in

accentuation of skin markings; usually indicative of

a chronic eczematous process

Term Definition

Macule A flat (impalpable) colour change

Milium A keratin cyst

Naevus A localised developmental defect (vascular,

melanocytic, epidermal or connective tissue)

Nodule A large papule (>0.5 cm)

Nummular Coin-shaped

Onycholysis Separation of the nail plate from the nail bed

Papilloma A benign growth projecting from the skin surface

Papule An elevated (palpable) lesion, arbitrarily <0.5 cm

in diameter

Patch A large macule

Pedunculated Having a stalk

Petechiae Pinhead-sized macular purpura

Pigmentation A change in skin colour

Plaque A papule or nodule that in cross-sectional profile is

plateau-shaped

Poikiloderma A combination of atrophy, hyperpigmentation and

telangiectasia

Purpura Non-blanchable redness (also called petechiae)

Pustule A papular lesion containing turbid purulent material

(pus)

Reticulate Net-like

Scale A flake on the skin surface, composed of stratum

corneum cells (corneocytes), shed together rather

than individually

Scar The fibrous tissue resulting from the healing of a

wound, ulcer or certain inflammatory conditions

Serpiginous Snake-like

Stria(e) A stretch mark

Targetoid Target-like

Telangiectasia Dilated blood vessels

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