Question | Answer |
Describe the pathological process of venous thrombosis | Formation of clotted mass within non-interrupted vascular system. Occurs in normal vessels, usually deep veins. Virchow's triad. |
What may predispose a person to venous thrombosis? | Immobility, heart failure, pregnancy, injury, surgery, clotting factor changes. |
Describe Virchow's triad | Endothelial abnormality/injury, alteration in blood flow (e.g. stasis, turbulence), hypercoagulability |
How do endothelial cells promote thrombosis? | On injury/activation - Release of von Willebrand factor, binding factors IXa + Xa, and tissue factor, activating extrinsic clotting cascade |
Describe how pain is experienced | Stimulation (damaging or on verge) of afferent pain nerve fibre causes release of Substance P, which stimulates AP along spinal cord, thalamus, and into the somatosensory cortex. |
Which skin receptor fibres are associated with pain? | A-delta fibres (fast) and C fibres (slow) |
What chemicals can cause pain by their release? | Histamine, prostaglandins, cytokines, bradykinin, neuropeptide transmitters. |
What measures can be taken to reduce the chances of atheroma? | Smoking cessation, low cholesterol diet, mobilisation and exercise, identifying family history, drugs (e.g. vasodilators, statins), surgical bypass. |
Describe the presentation of DVT | Calf warmth/tenderness/swelling, mild fever, pitting oedema, Homans' sign (^resistance/pain on forced foot dorsiflexion) |
Describe the presentation of a soft tissue infection | Acute inflammation (rubor, calor, dolor, tumor), fever |
Give some examples of soft tissue infections | Cellulitis (Strept. pyogenes, S. aureus), gas gangrene (C. perfringens), necrotising fasciitis (in immunocompromised - Strep. or E. coli), Melaney's synergistic gangrene (S. aureus or Strep.) |
How do opiates effect pain transmission? | Opiate binds to opiate receptor on afferent pain fibre, blocking release of substance P and therefore blocking pain transmission |
How do NSAIDs help reduce pain? | NSAIDs inhibit the release of prostaglandin (a nociceptor-stimulating chemical) |
Discuss the mechanism of TENS | Transcutaneous electric nerve stimulation is the stimulation of of non-pain low-threshold afferent fibres, causing inhibition of neurons in pain pathways (much like rubbing the skin after a bump) |
Describe the mechanism of acupuncture | Activates afferent neurons leading to spinal cord and mid-brain centres that release endogenous opioids |
What are the 4 causes of haemarthrosis of the knee? | Peripheral meniscal tear, intra-articular fracture, bleeding disorder, * cruciate ligament rupture * |
How can a tear between the quardraceps and the patellar tendon be tested for? | Active straight leg raise |