D | Basicmedical Key

D filler see valgus pad; Table P1

dactylitis; sausage toe digital inflammation characteristic of psoriatic arthropathy but also associated with other sero-negative arthritides, e.g. Reiter’s disease

dactylosis see ainhum

Dakin’s solution chlorinated soda solution BPC; tissue-irritant and healing-inhibitory antiseptic solution liberating 0.5% chlorine

Daktarin see miconazole nitrate

damped sine wave the intermittent energy wave pattern from an electrosurgery unit used to achieve fulguration, desiccation or coagulation of soft tissues (see Table E2); energy that cuts through tissue and achieves simultaneous homeostasis from a moderately damped sine wave allows ‘bloodless’ surgery

dance-related injuries Table D1

Table D1 Categorization of dance-related lower-limb and foot injuries

Innate feature	Comments
Natural physique	Dance-related injuries are more likely in female dancers who are not naturally very slim, long-backed and long-legged, with exceptional spinal, leg and foot joint mobility, and in male dancers who do not naturally possess a light muscular body
Dance technique	Long-term overuse injury relates to incorrect dance techniques practised during daily class and frequent performances
Overuse	Dancers who have any degree of unrecognized or uncorrected pathomechanical foot/limb problem are predisposed to overuse injury (dance requires hours of daily practice to train and perfect technique)
Mishap	Bravura techniques inherent to intricate dance manoeuvres predispose to accident injury

dancer’s pad prescription orthosis that reduces sesamoid trauma by dispersing plantar pressures away from first metatarsophalangeal joint

dander animal hair, skin or feather particles that trigger allergic reaction in sensitive individuals

disease, Darrier’s see keratosis follicularis

DASA see distal articular set angle

data-gathering Table D2

Table D2 Principles of data-gathering – factors within the medical history interview

Interventions	Comments
Facilitation	Actions/postures/words that communicate the interviewer’s interest in what the patient is saying
Reflection	The interviewer repeats the patient’s key words, to encourage the patient to continue speaking
Clarification	Requesting more support information and meaning, to ensure that the interviewer’s interpretation is the same as the patient’s meaning
Empathy	Words/actions that communicate that the interviewer recognizes the patient’s feelings
Ask about the feelings	Direct questions on what the patient felt in terms of pain, discomfort, an event or a symptom
Interpretation	Summarization and paraphrasing of what the patient has said during the interview to ensure that there is no misunderstanding
Confrontation	Stating something about the patient’s responses (feelings/behaviours) which are inconsistent with other symptoms or signs

Davis’ law see law, Davis’

daylight sign see sign, Sullivan’s

DCCT, 1993 Diabetes Control and Complications Trial

DDx see differential diagnosis

DeBiFVaN protocol for systematic evaluation of the lower limb and foot, forming part of the overall examination of the podiatric patient; De, dermatological examination; Bi, biomechanical examination; F, footwear; VaN, vascular and neurological examination

debilitating causing weakness

debridement excision of devitalized and/or necrotic tissue, to promote healing

decalcification pathological removal of calcium salts from bones

decomposition decay, disintegration or lysis

decomposition of movement lack of smooth voluntary movements, characteristic of cerebellar lesions; due to lack of muscular (agonist, antagonist and synergist) coordination

decompression removal of pressure

joint decompression surgical procedure to reduce intra-articular pressures

nerve decompression nerve pressure release, by excision of local bony or fibrous tissues

decompression osteotomy surgery to increase first metatarsophalangeal joint range of movement

decompressive fasciotomy division of intercompartmental fascia to reduce increased intracompartmental pressures

decubitus ulcer; pressure sore long-standing chronic wound formed by tissue breakdown in response to intermittent pressure at skin surface (especially skin overlying sacrum, greater trochanters and heels) in poorly perfused, ischaemic or neuropathic tissues in elderly, debilitated and bed-bound patients, or at the plantar and digital areas in patients with distal sensory neuropathy or lower-limb/foot neuroischaemia

decussate crossed, as the arms of an X (e.g. decussation of pyramidal tracts)

deep fascia see fascia, deep

deep peroneal nerve; anterior tibial nerve division of the common peroneal nerve; it courses distally lying between tendons of extensor hallucis longus and extensor digitorum longus at (anterior ankle area) and passes into the dorsal foot; it supplies all anterior compartment muscles and extensor digitorum brevis; distal fibres supply skin sensation to dorsal aspect of first or second interdigital cleft (see syndrome, anterior tarsal)

deep peroneal nerve block; fibular block see anaesthesia; deep peroneal block

deep peroneal nerve entrapment see syndrome, anterior tarsal

deep posterior compartment muscular compartment of the lower leg deep to, and separated by fascial tissue from, the superficial muscle compartment, and overlying posterior aspect of interosseous septum between tibia and fibular (see syndrome, compartment) and Figure C2

deep reflex: jerk see reflex, deep tendon

deep retrocalcaneal bursa see bursa, deep retrocalcaneal

deep retrocalcaneal bursitis deep retrocalcaneal bursa inflammation usually due to local intermittent trauma (e.g. from heel counter of shoe); causes diffuse posterior heel pain (exacerbated by dorsiflexing the ankle) but only minor visible swelling; palpable as a fluctuant swelling to either side of Achilles tendon, immediately superior to its insertion into calcaneum; treated by isolating and removing the cause, plus use of an in-shoe 7-mm semicompressed heel pad

deep tendon reflex; DTR see reflex, deep tendon

deep transverse plantar ligament; DTPL bands of tough fibrous tissue between plantar plates of adjacent metatarsophalangeal joints, which prevent lateral spread of metatarsal heads during weight bearing; interossei lie dorsal to DTPL and the lumbricals and plantar digital nerves and vessels lie on its plantar aspect (see Table M16)

deep venous thrombosis; DVT thrombosis formation within deep veins of calf and/or thigh, strongly associated with prolonged immobility (e.g. enforced bed rest, surgery or long-haul air flights); local symptoms include mild to moderate calf/thigh pain exacerbated by exercise, and cyanosis, swelling, distension of superficial veins and tissue warmth distal to thrombosis site; Homan’s sign is positive if calf veins are affected; detachment of clot fragment can cause pulmonary embolism and sudden death; treatment includes rest + limb elevation, antibiosis, anticoagulation; differential diagnosis should exclude ruptured Baker’s cyst

defibrillation part of immediate life support of collapsed patient; use of automated electrical defibrillator device to arrest atrial or ventricular fibrillation and restore normal cardiac sinus rhythm (see electrocardiogram)

degeneration retrogressive, pathological cell or tissue changes and associated loss of function

degenerative joint disease see osteoarthritis

dehiscence suture line failure secondary to wound infection, tissue necrosis or foreign body; wound healing fails to proceed to completion at the normal rate; treatment includes meticulous wound cleansing and debridement, antibiosis as necessary, and regular redressing until wound healing is complete

Déjerine–Sottas disease see disease, CMT disease type III

delayed hypersensitivity see allergic reactions

delayed-onset muscle soreness; DOMS muscle soreness secondary to exercise, characterized by increasing pain/discomfort during subsequent 24–72 hours, and subsiding within a few days

delayed phase see triple-phase bone scan

delirium acute confusional state secondary to systemic pathology (e.g. infection, pyrexia, chronic long-term hypothyroidism, marked vitamin B₁₂ deficiency, chronic alcoholism) or induced by pharmacological agents (e.g. nitrazepam, carbidopa and benhexol); common in elderly patients with psychiatric illnesses; Box D1

deltoid ligament medial collateral ligament of the ankle (see Table A7)

dementia acquired intellect, memory and personality impairment; most common psychiatric disorder affecting the elderly (e.g. affecting ∼20% of those aged > 80 years) (Table D3)

Table D3 Causes of dementias that affect the elderly

Dementia type	Percentage of cases
Alzheimer’s disease	∼ 60%
Cerebral infarction	∼ 10%
Neurological conditions, such as Pick’s disease, Huntington’s chorea, Creutzfeldt–Jakob disease, chronic alcoholism, Parkinson’s disease	∼ 10%
Other conditions, such as depression, cerebral tumours, drug use, hypothyroidism, pernicious anaemia, vitamin deficiencies in which the dementia tends to clear as the problem is resolved	∼ 10%

demi- ; semi- ; hemi- half

demi-pointe foot position in dance, where body weight is supported by metatarsal heads and ankle joint is fully plantarflexed (i.e. on tiptoes)

demineralization loss of or decrease in mineral content of bone

demography statistical study of specific population groups, e.g. in relation to age, environment, geographical distribution

demyelinating diseases group of central and peripheral nervous system disorders characterized by progressive and/or segmental demyelination of nerves and resultant loss of neurological function, e.g. multiple sclerosis, diabetes mellitus

demyelination loss or destruction of myelin sheath surrounding nerves, with associated loss of effective nerve impulse conduction; characteristic of demyelinating diseases

dendrites terminal arborizations of the nerve cell axon

denervation loss of nerve supply

Denis Browne splint bespoke boots joined by a midfoot articulated bar or brace, to maintain the (child’s) feet in a near-anatomical position during ambulation; used in treatment of congenital talipes equinovarus

dentate toothed; notched

deodorant agent that corrects offensive odours by absorption (e.g. powdered charcoal), antiseptic action (preventing bacterial decomposition of sweat), oxidization (e.g. potassium permanganate, hydrogen peroxide) or decreasing sweat flow (e.g. topical formalin, aluminium acetate, charcoal, boric acid)

deoxygenation depriving of oxygen

deoxyribonucleic acid; DNA nucleic acid within chromosomes of cells and many viruses; the ‘genetic fingerprint’ of the individual

DEPA ulcer classification system see Table U2

depigmentation congenital or acquired, partial or total loss of pigment

depressor muscle whose action flattens or lowers a body part

Derby shoe; Gibson shoe laced shoe with a tongue continuous with the vamp; the shoe throat opens far wider than that of an Oxford-style shoe; suitable for patients with a wide forefoot or pes cavus

Dermagraft fibroblast-derived dermal replacement wound dressing

dermal of dermis

dermal naevus see subcutaneous naevus

dermal plexus; DP fine meshwork of nerves, arterioles and capillaries supplying sensation and blood nutrients to dermis, epidermis and epidermal appendages; subdivided into superficial (i.e. within papillary layer of dermis), intermediate and deep (i.e. within deeper fibrous part of dermis, just superior to subcuticular fatty layer) dermal plexuses

dermatitis inflammation of dermis or skin (see eczema)

actinic dermatitis ultraviolet- or sunlight-induced dermatitis

acute dermatitis characterized by acute inflammation with pruritus/pain, redness and scaling, weeping and vesiculation

allergic contact dermatitis see dermatitis herpetiformis, contact

chronic dermatitis characterized by chronic inflammation and pruritus, lichenification (thickening) and excoriation (scratch marks) of affected skin areas

contact dermatitis acute inflammatory skin reaction characterized by eczema and vesiculation in skin areas contacted by an allergen (e.g. latex, causing allergic contact dermatitis) or a specific irritant (e.g. chemicals used in leather tanning, causing irritant contact dermatitis)

dermatitis herpetiformis chronic skin disease characteristic of coeliac disease, with groups of severe, extensive, pruritic papules, subepidermal blisters and dermal microabscesses on extensor surfaces

exfoliative dermatitis see disease, Wilson’s

irritant contact dermatitis see dermatitis herpetiformis, contact

seborrheic dermatitis ‘chronic flaking of skin, especially of the scalp (causing dandruff), face, chest and limb flexures; in adults may be associated with malassezia fungal skin infection, Parkinson’s disease and epilepsy’

stasis dermatitis eczema, atrophy, dystrophy of skin overlying tissue areas with reduced venous drainage and/or chronic venous hypertension, especially those with history of deep-vein thrombosis and/or varicose veins; affected skin areas show chronic inflammation, oedema, lichenification, haemosiderosis and tissue congestion classically in the lower one-third of leg

dermatofibroma; histiocytoma cutis; fibrous histiocytoma sclerosing haemangioma: common benign fibroma of extremities; flat/slightly raised flesh-coloured/yellowish-brown, firm/hard, non-progressive, isolated lesions usually <1 cm in diameter; palpable bulk of lesion extends beyond its visible outline

dermatoglyphics finger and toe prints; pattern of lines and whorls in pulp skin unique to the individual

dermatome (1) instrument for skiving thin sections of donor skin in preparation for skin graft

dermatome (2) area of skin supplied by cutaneous branches of a spinal nerve (Figure D1)

Figure D1 (A) Dermatomes: areas of lower limb skin supplied by cutaneous branches of spinal nerves. (B) Sensory dermatomes of the foot. This article was published in Neale’s Disorders of the Foot, Lorimer, French, O’Donnell, Burrow, Wall, Copyright Elsevier, (2006).

dermatomycosis see dermatophytosis

dermatomyositis skin involvement in polymyositis, characterized by purple discoloration of eyelids and collodion patches (i.e. scaly red, vasculitic areas of skin overlying digital joints), ulcerative vasculitis and calcinosis of subdermal tissues

Dermatophagoides pteronyssinus house dust mite; its faeces contribute to house dust, causing atopic asthma if inhaled by susceptible individuals

dermatophyte reactions; id reactions allergic-type reactions (i.e. asymptomatic desquamation of palmar skin) associated with plantar dermatophytosis; treatment of the foot condition leads to spontaneous resolution of palmar allergy; some reactions present as podopompholyx (i.e. vesicular eruptions of plantar skin) or cheiropodopompholyx (vesicular eruptions of both palmar and plantar skin); vesicle fluid is negative to fungal culture; condition usually clears spontaneously when primary fungal infection subsides

dermatophytes common fungal species infecting skin, nails and hair, e.g. Trichophyton rubrum, T. mentagrophytes var. interdigitale and Epidermophyton floccosum

dermatophytosis inflammation of skin, nails and hair follicles due to dermatophyte infection, causing erythema, itching, papular vesiculation, interdigital and heel fissures and skin scaling; superficial infections are common in adults, especially those with dyshidrosis, living in community, using communal sports or bathing facilities, diabetics or those on long-term antibiotic or immunosuppressive therapies (see onychomycosis; tinea pedis; Table A13)

dermatosclerosis see scleroderma

dermatosis non-specific term denoting any cutaneous lesion or skin eruption of any type

dermis; corium vascular area of connective tissue of skin, immediately deep to the epidermis; formed of two layers: upper dermal layer (stratum papillare) forms upward projection between the epidermal rete pegs; deeper dermal layer (stratum reticulare) contains and supports dermal nerves, blood vessels and lymphatics, and overlies subcuticular fat layer and superficial fascia

dermoepidermal junction; DEJ undulating basement membrane zone between superficial (stratum papillare) and basal layer (stratum basale) of the epidermis

dermoid cyst see synovial cyst

dermoscopy; epiluminescence microscopy diagnostic technique to demonstrate early malignant changes within pigmented nail lesions, or to identify dermal vascular changes in scleroderma and systemic lupus erythematosus

desiccant drying agent

desiccation separation of a skin lesion from underlying healthy tissue, using low-current electrosurgery

desloughing agents; cleansing agents alginate, hydrogel and hydrocolloid dressings and other chemical agents applied to slough to facilitate its separation from granulation tissue within a wound bed; e.g. hypochlorites, Aserbine solution, autolytic enzymes (streptokinase and streptodornase), cadexomer iodine

desmosomes tight intercellular junctions formed by apposed areas of thickened cell membrane; intermediate filaments of one cell link with those of an adjacent cell; see cytoskeleton; intermediate filaments

desquamation normal, continuous loss (shedding) of keratin flakes (squames) from the outer layer of epidermis at the skin surface, so that overall skin thickness remains constant, even though keratinocytes continually generate at the basal layer (stratum basale)

detergents chemicals used to remove greasy/foreign material and dirt from surfaces

anionic detergents soaps and fatty alcohols, incompatible with cationic detergents

cationic detergents quaternary ammonium compounds, e.g. Cetrimide and Roccal; bactericidal to many Gram-positive microorganisms but having little or no effect on Gram-negative microorganisms

detoxification metabolic conversion of pharmacologically active agents into pharmacologically inactive principals (e.g. metabolic breakdown of local anaesthetic drugs by liver enzymes)

devascularization occlusion of all or most blood vessels within an area of tissue

deviation deflection

devitalized (of tissues) devascularized

DEXA dual-energy X-ray absorptiometry

dexter right

dextropropoxyphene see co-proxamol

Diabetes Control and Complications Trial (DCCT, 1993) this US study recorded the effects of glycaemic control on the development of diabetes-related complications; demonstrated that tight glycaemic control significantly reduces development of macro- and microvascular and neurological (autonomic, sensory and motor) complications (see Quality outcomes Framework for Diabetes Mellitus [2006])

diabetes insipidus; DI disease due to insufficient production of antidiuretic hormone (ADH, vasopressin) at the posterior pituitary; characterized by voiding large volumes of very dilute urine, with resultant nocturia and dehydration; patients are treated by replacement hormone (vasopressin or desmopressin)

diabetes mellitus; DM multiaetiology metabolic disease due to reduced/absent production of pancreatic insulin, and/or insulin resistance by peripheral tissue insulin receptors; characterized by reduced carbohydrate metabolism and increased fat and protein metabolism, leading to hyperglycaemia, increasing glycosuria, water and electrolyte imbalance, ketoacidosis, coma and death if left untreated; chronic long-term complications of DM include nephropathy, retinopathy, neuropathy and generalized degenerative changes in large and small arteries; treatment (with insulin/oral hypoglycaemic agents/diet) aims to stabilize blood glucose levels to the normal range (difficult to achieve fully; patients may tend to hyperglycaemia or hypoglycaemia due to mismanagement of glycaemic control); Tables D4–D7

Table D4 Presentations of diabetes mellitus

Presentation of DM	Characteristics
Type 1 DM (formerly termed IDDM)	Tends to affect younger people; acute-onset disease with weight loss and marked dehydration; untreated leads to ketoacidosis, coma and death; treated by diet control and lifelong insulin
Type 2 DM (formerly termed NIDDM)	Tends to affect older people (>35 years old); chronic-onset disease with gradual weight gain and symptom onset; untreated leads to PVD, MI, CVA, and possibly ketoacidosis, coma and death; treated by diet control ± oral hypoglycaemic agents, and possibly insulin therapy in the long term
MODY	Affects young people, but shows the characteristics of type 2 DM
Gestational DM	Characteristics of type 2 DM, which resolve after parturition
Low-birth-weight DM	As type 2 DM, presenting in adulthood in patients who were of low birth weight and/or those who were undernourished as children (including anorexics)
Pre-diabetes (insulin resistance)	Subjects, such as those with obesity, lichen planus, acromegaly, polycystic ovary syndrome, history of anorexia, may show a poor response to a glucose tolerance test, and tend to go on to develop type 1 or type 2 diabetes later in life

IDDM, insulin-dependent diabetes mellitus; NIDDM, non-insulin-dependent diabetes mellitus; PVD, peripheral vascular disease; MI, myocardial infarct; CVA, cerebrovascular accident.

Table D5 Diagnosis of diabetes mellitus

Test	Test result indicating diabetes mellitus
Blood glucose levels	Fasting blood glucose (FBG), tested at >14 hours since eating >6.7 mmol/L Random blood glucose (RBG), tested ∼2 hours since eating >10 mmol/L Glucose tolerance test (GTT) indicated for FBG 5.6–6.7 mmol/L
Urinalysis	Glucose Ketones
Blood analysis	Glucose, creatinine, electrolytes and arterial pH, PO₂ and PCO₂
HbA1_C	>5–8%

Table D6 Treatment of diabetes mellitus

Diabetes presentation	Treatment modality
Type 1, insulin-dependent	Diet Supplementary insulin ± oral hypoglycaemic agents
Type 2, non-insulin- dependent	Diet Oral hypoglycaemic agents
Type 2, insulin-dependent	Diet Supplementary insulin ± oral hypoglycaemic agents

Table D7 Long-term systemic complications that predispose to foot problems in patients with diabetes mellitus

Complication	Feature
Vascular	Accelerated formation of atherosclerosis, especially affecting distal (lower-limb) arteries Abnormal vascular endothelium and associated changes of the microvasculature Medial arterial sclerosis; Mönckeberg’s sclerosis of the intermetatarsal arteries
Altered blood components	Abnormal erythrocytes cause tissue ischaemia (erythrocytes do not adopt normal flow characteristics in small vessels; oxygen dissociation is reduced) Abnormal white blood cells predispose to poor healing and susceptibility to infection (white blood cells show less effective phagocytosis, release fewer growth factors and reduced destruction of microorganisms)
Neurological	Abnormal peripheral (motor, sensory and autonomic) nerve conduction, with reduced perception of and reaction to potentially damaging stimuli; autonomic dysfunction predisposes to dryness of the skin, heel fissures, abnormalities of skin blood flow and Charcot joint formation (neuroarthropathy)
Increased susceptibility to infection	Owing to the combined effects of neurological and vascular complications, and altered blood components (see above)
Impaired vision	Diabetic retinopathy and cataract formation reduce the patient’s ability to examine the feet and react promptly to potential problems at an early stage
Renal disease	Renal dysfunction predisposes to peripheral oedema Correlation of renal disease and median arterial calcification (Mönckeberg’s sclerosis) Risk of digital gangrene in renal transplant patients
Non-enzymatic glycation of protein	Affects all body proteins, causing ‘stiffness’ of globular and structural proteins, with: • Joint immobility, especially of the subtalar joint • Loss of normal resilience of epidermal keratin • Contracture of the fascial structures (formation of the diabetic ‘claw-foot’, with increased loading under the metatarsal heads) • Impaired wound healing, with chronic underlying fibrosis and ischaemia of long-standing chronic wounds (ulcers) and reduced tissue viability