Compartment Syndrome

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Orthopedics: Compartment Syndrome
This is a syndrome that results from swelling of a muscle. The muscle is retained in its fixed volume fascia, however, and thus the swelling of the muscle causes occlusion of the blood supply. this can result in infarction, and can cause an ischaemic contraction known as Volkmann’s Ischaemic Contracture.
It typically occurs in the forearm and calf, but can also occur in the thigh and foot.

Compartment Syndrome


Causes

-          Trauma – compartment syndrome is often a complication of fracture.
-          Continued pressure on a limb – e.g. lying for hours in the same position on the same limb – often seen in drug and alcohol abuse. 

Pathophysiology

-          Swelling of the muscle – usually as a result of post-traumatic bleeding and oedema.
o   Initially only venous flow is disturbed, and arterial flow (due to its greater pressure) still occurs.
o   Eventually, the pressure within the compartment exceeds the arterial pressure, and the muscle begins to undergo ischaemia.
§ The main arteries in the compartment have a higher pressure than the arterioles, and thus these may not be occluded until late on, if at all
§ Other structures close by are also affected by the ischaemia – e.g. nerves, but the nerves are not affected until the pressure is very high!
§ This means that distal pulses and neurological exam are usually normal until VERY LATE ON!
·         If there are reduced or absent pulses, then it is likely the diagnosis is too late to stop severe ischaemic damage.

Clinical features and diagnosis

-          Often co-exists with fractures
-          You should be suspicious if there is:
o   Pain increasing over time – despite appropriate analgesia and joint immobilisation
-          People particularly at risk are children/young adults with:
o   Tibial shaft fractures
o   Forearm injuries
o   Crush injuries
-          There is often increased pain on passive flexion and extension of the fingers and toes of the affected limb
-          Measure compartment Pressure:
o   <30mmHg is normal
o   >40mmHg is high
o   Compare diastolic arterial and compartmental pressures – the difference needs to be >30mmHg for adequate perfusion.
o   In children – compartment pressures are not routinely monitored

Treatment

-          Fasciotomy – of the muscle compartments involved. Do it as soon as possible! To minimise the risk of irreversible ischaemia.
o   If there is any doubt over the diagnosis, perform fasciotomy anyway!


Notes by Tom Leach

Carpal Tunnel Syndrome (CTS)

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Orthopedics: Carpal Tunnel Syndrome (CTS)
Epidemiology and Aetiology
-          More common in women
-          Typical presentation at age 30-50
-          Associated with gout, pregnancy, the pill, premenstrual state, rheumatoid arthritis, diabetes, acromegaly, obesity, amyloidosis
-          Some believe that jobs that involve repetitive flexing of the wrist may be involved.
o   RSI – repetitive strain injury – is a fallacy and doesn’t actually exist! There is usually another underlying diagnosis.
-          Most cases are ideopathic
Carpal Tunnel Syndrome

Pathology
-          Compression of the median nerve as it passes through the carpal tunnel (under the flexor retinaculum)
Signs and symptoms – are those of median nerve compression:
-          Wasting of the thenar eminence (the chunky muscle on the palmar aspect of the base of the thumb) – is often a late sign
-          Parasthesia of the lateral 3½ fingers (thumb, forefinger and middle finger)
-          Pain / tingling in the lateral 3 fingers
o   Pain is often worse at night and may wake the patient. It is often a burning or aching sensation.
-          The median nerve also supplies the lateral part of the palm but typically, this is spared as this branch of the median nerve does not pass through the carpal tunnel.

Examination
-          Look for wasting of the thenar eminence
-          Check sensation on the lateral 3½ fingers
-          Phalens Test – ask the patient to hold their wrists in a flexed position for 1-2 minutes. May elicit / exaggerate typical symptoms
-          Tinel’s Test – tap over the medial aspect of the inside of the wrist. Can induce tingling sensations. Less likely to elicit signs than Phalens
o   “Tinels – Tapping, Phalens – Flexing”

Investigations
-          Diagnosis is usually clinical, but occasionally in difficult cases, nerve conduction may be performed.

Management
-          Conservative – occasionally simple life-style changes (e.g. placement of computer keyboard) may be beneifical.
-          Splint – can be worn at night to reduce nocturnal symptoms, and many patients may also wear it during the day
-          Pain relief – is typically in the form of NSAIDs
-          Carpal Injection – hydrocortisone acetate – can be used if other methods have failed to control symptoms. Inject just dorsal to the wrist crease. Provide pain relief for approximately 1 month. Longer acting pain relief is no more effective than placebo.
o   May cause a sensation of shooting and tingling if you touch the nerve. If this is the case, you are in the wrong place! You are not aiming for the nerve itself, but for the flexor tendons.
o   Wearing a splint for a few days after injection can reduce the symptoms induced at time of treatment
-          Surgical decompression can be used for patients who still fail to respond. This can be open or endoscopic surgery.
o   Wearing a splint for a few days after injection can reduce the symptoms induced at time of treatment

Notes by Tom Leach

Elhers-Danlos Syndrome (EDS)

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Rheumatology: Elhers-Danlos Syndrome (EDS)
Elher-Danlos syndrome is an inherited connective tissue disorder caused by defective collagen synthesis. Symptoms vary widely between individuals. Some may be hardly effected, whilst other live severely restricted lives.


Elhers-Danlos Syndrome (EDS)


Epidemiology and Etiology
  • Several types of the disease (5 main types, + some rarer ones), inheritance depends on the type. Most are autosomal dominant, but some are recessive
  • Thought to affect about 1 in 5000 births
Pathology and clinical findings
  • Defective collagen synthesis, resulting in insufficient and/or ineffective collagen. Affected organs vary depending on the type of the disease, although there is often some degree of all the features below, regardless of what type:
    • Classical (common)hyperelasticity of the skin
    • Hypermobility type (common)hypermobility of joints. Joints are prone to sprain, dislocation, effusion and subluxation
    • Vascular type (rare) easy bruising, aneurysms
    • Ocular-kyphoscoliotic type (rare)– weak sclera, predisposing to perforation of the globe, and kyphoscoliosis of the spine.
    • Arthrokalasis (rare)– characterised by bilateral congenital dislocation of the hip
    • Other types – extremely rare (e.g. <50 reported cases worldwide)
  • Other signs and symptoms
    • Flat feet
    • Poor healing / thin skin particularly scar tissue – can be difficult to suture in surgery as the skin just rips
    • GI bleeds / perforation
    • Hypotonia
    • High, narrow palate
    • Molluscoid pseudotumours – fleshy outgrowths at the site of pressure points
    • Aneurysm
    • Increased risk of pneumothorax
 
Diagnosis
  • Usually clinical
  • Usually a FH
Prognosis and Treatment
  • Life expectancy is usually normal
  • However, some complications are potentially lethal (e.g. ruptured aortic aneurysm)
  • There is no particular treatment
  • Management may involve:
    • Minimising the risk of trauma – this could be with the use of protective clothing / padding
    • Extra precautions to ensure haemostasis during surgery – also watch out for suturing wounds – don’t leave the skin under excessive tension
    • Extra precautions during pregnancy and delivery
    • Genetic counselling – particularly if planning pregnancy
     

    Fractures 1

    Fractures 1

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    Orthopedics: Fractures
    General Info
    -          fractures can involve part of, or all of the bone cortex
    -          Open fracture – the skin or overlying mucous membrane is breached
    -          Closed – there is no damage to the overlying skin or mucous membrane
    Types of Fracture
     
    Presentation
    -          Fractures are always Painful!
    -          Often involve trauma (except for pathological fractures)
    -          Tender
    -          Often swollen
    -          Mobile at fracture site
    -          Loss of limb function
    Investigations
    See also the article on Bone Radiology
    -          X-ray – the investigation of choice.
    o   All suspected fractures should be x-rayed from 2 planes! – AP, and lateral. This allows you to judge the level of displacement, comminution, angulation and rotation.
    -          Bone scans – if you can’t see a fracture on X-ray, but you still highly suspect one, then you might do a bone scan. There is increased Tc uptake at sites of fracture, so fractures will appear dark on bone scan.
    o   This effect is less apparent in older patients due to reduced osteoblastic responses to the scan. In such patients, you might have to wait one week between giving the radioactive isotope and performing the scan.
    o   Particularly useful for femoral neck and sacral injuries in the elderly, and carpal tunnel injuries in the young.
    -          CT – useful if you can’t see anything on x-ray. Make sure the scan is perpendicular to the fracture line!
    o   CT is also very good at detecting new bone formation, and so can detect subtle stress fractures.
    -          MRI – once again, useful if x-ray looks normal. MRI’s can be especially good, as a T1 scan can show the fracture immediately, (bone scans and CT can take a while), whilst T2 are good for showing up older fractures.
    General Complications of Fracture
    Early Complications
    -          DVT and PE – possibly the most common post fracture complication. Take preventative measures:
    o   Stockings
    o   Leg pumps
    o   LMW heparin (in selected patients!)
    ·         Compartment Syndrome – full article
    -          Vascular injury
    o   May lead to avascular necrosis - this usually occurrs in the hip, but can occur at the end of any long bones, sometimes without associated fracture! Tends to occur within 48 hours of fracture. Needs to be treated with a total hip replacement (THR). X-ray will be normal in the early stages, but in the late stages, affected bone areas will be darker than normal bone, due to collapse of subchondral bone.
    o   Generally rare, but well recognised
    o   Usually associated with open, high energy fractures.
    o   Signs include; cold pulseless limb, ischaemia, paralysis and parasthesia of the limb
    § If there is ischaemia, you should presume there is arterial disruption until proven otherwise.
    § Angiography confirms the diagnosis
    § Treated with surgery to revascularise the limb. Also, often just closing an open fracture can help perfusion.
    ·         You may use a temporary vascular shunt to prevent damage whilst more permanent surgery is performed
    ·         The limb should be fixated before you operate on the vessels
    ·         Nerve Injury – particularly if the fracture affects the knee (common peroneal nerve). Look for foot drop and loss of sensation on the dorsum of the foot. The majority of nerve injuries are traction neuropraxia – i.e. the nerve remains intact, but is temporarily unable to transmit nerve impulses. These will subsequently recover. Prognosis for nerve injury is generally good, but many patients might not make a complete recovery
    § It is important to make detailed notes and examination of nerve injury before surgery – as if the nerve injury is only noted after surgery, the surgeon may be liable.
    -          Vascular injury
    Late Complications
    ·         Mal-union – the separate areas of bone heal, but with incorrect alignment. Proper placement and reduction of the fracture at the time of injury can prevent it.
    ·         Nonunion – the separated areas of bone do not fuse. More common in smokers. Often occurs when a fracture is ‘missed’ on x-ray and thus the correct treatment is not administered (e.g. immobilisation in a cast). There is usually some tissue development between the two fractured pieces. This can be scar tissue, or more rarely, a pseudo joint forms with cartilaginous articulating surfaces. If union has not occurred by 6 months, then it is unlikely to do so without intervention. Typically a diagnosis of non-union requires an x-ray at >6 months demonstrating non-union of the fractured ends of the bone.
    ·         Delayed union – difficult to distinguish between delayed and non-union. X-ray at 6 months is definitive. In both instances the joint is likely to be painful throughout.
    Other complications
    -          Infection
    o   Can be early or late
    o   Gas Gangrene
    § Infection, usually by chlostridium, that produces gas within tissues. Rare.
    ·         Algodystrophy – (Sudeck’s Atrophy) – aka Reflex sympathetic dystrophy syndrome and Complex regional pain syndrome
    ·         This typically occurs in the hand or foot after injury, sometimes after only mild injury. It occurs after about 5% of all trauma injury, and can also occur after frostbite and long periods of immobilisation.
    ·          It results from injury to the sympathetic nervous system which inturn, affects the blood supply to the affected region.
    ·         Typical features include:
    o   Burning pain in the affected area
    o   Skin changes – skin often becomes thinned and shiny
    o   Swelling
    o   excessive sweating – at the affected site
    o   Pain stiffness and muscle wasting may become worse with progression, as the patient is reluctant to use the affected body part.
    ·         It can often be successfully treated with physiotherapy, although this can be a lengthy process
    Hip Fractures - Neck of Femur (NoF)
    -          The most common type of fracture
    -          Typically occur in elderly female patients
    o   Also common in high impact trauma – e.g. car accident
    o   Female:Male ratio is 4:1
    o   Mean age is 75
    o   Dementia or cognitive impairment present in 30% of cases
    -          The majority will require corrective surgery
    -          Mortality – 20-35% in the first year
    o   80% of mortality is in women
    Types
    -          Extracapsular – fractures that occur outside the joint capsule
    o   Do not affect the blood supply to the femoral head
    o   Typically occur in well vascularised bone, and thus complications of bone union are rare
    o   Often described as stable, ort unstable. Unstable fractures are generally those where there is detatched fragment of lesser trochanter.
    -          Intracapsular – fractures that occur inside the joint capsule
    o   Can affect the blood supply to the femoral head, especially if the fracture is displaced.
    o   Complications of fracture union are common
    Presentation
    -          History of fall / trauma
    -          Leg may be shortened and externally rotated in displaced fractures.
    -          10% will have a fracture at another site, usually proximal humerus, or distal radius.
    -          Neurovascular injury is rare…
    o   But avascular necrosis is more common here than at other sites. Often treated with total hip replacement.
    o   The sciatic nerve is at risk in dislocation fractures, and dislocations (15% of patients).
    Treatment
    Nearly all will be given surgery, unless there are significant CI’s.
    -          Intracapsular fractures:
    o   Undisplaced – up to 15% will displace without treatment, and thus the usual treatment is internal fixation using a dynamic hip screw.
    § 5% will have avascular necrosis – these cases will need arthroplasty (hip replacement)
    o   Displaced – can be treated by reduction and fixation, but there is a high risk of non-union, and fixation failure. 15% will have avascular necrosis .40% of patients treated in this way will require arthroplasty at some point in the future. Thus, many surgeons opt for hemiarthroplasty as the first line. In hemiarthroplast, the femoral head but not the actebular cup is replaced. (In a total hip replacmenet both the head and the cup are replaced, but this is typically reserved for osteoarthritis).
    § Reduction and fixation more likely to be carried out in younger patients – as long as there is no underlying pathology (e.g. steroids causing osteoporosis) that caused the initial fracture.
    -          Extracapsular fractures
    o   Internal fixation is the treatment of choice for inter-trachanteric fractures. as the blood supply to the femoral head is not in danger. Unlike intracapsular fixation, a sliding screw and plate fixation  (aka Dynamic Hip Screw) is used. AN intra-medually hip screw is used for sub-trochanteric fractures. Other methods may be used for fractures that extend a long way down the femoral shaft. Complications include:
    § Failure of fixation (5%)
    § Non-Union – (1-2%)
    § Infection (5%)
    Dynamic Hip Screw Intra-Medually Screw
    Dynamic Hip Screw - almostadoctor.com - free medical revision notes
    Intramedually Hip Screw - almostadoctor.com - free medical student revision notes
    Prognosis
    This is generally poor, irrespective of the fracture location. This tends to be a reflection of the general health of the patient’s involved (elderly women), and not an indication of the surgery itself.
    -          1 year mortality – 30%
    -          1 year mortality in those with dementia – 50%
    -          Only 70% of patients will return home. The rest will require residential care for the rest of their lives
    Upper Limb Fractures and Dislocations
    Dislocated Shoulder
    -          Patient will support affected arm with other arm
    -          Dislocation usually occur anteriorly – thus traumatic injury is often from behind
    -          Should may appear ‘flattened’
    -          Palpation of the joint will reveal displaced greater tuberosity, and unusual bulge below the clavicle.
    -          May be anaesthesia over the attachment of deltoid (axillary nerve)
    -          Treatment
    o   Can try to relocate the joint manually
    o   Will often spontaneously resolve in a few weeks
    Fracture of shaft of humerus
    -          Common traumatic injury in the elderly
    -          Extensive bruising of the upper arm
    -          Wrist drop common – due to involvement of the radial nerve which runes in the spiral groove of the humerus. In closed injuries, the nerve damage is usually reversible (traction neuropraxia)
    -          Treatment – as long as the injury is closed, then splitting of the wrist and a cast over the break is usually sufficient to allow for healing
    Suprecondylar fracture of the humerus
    -          Only really seen in childhood, but it is a common fracture for children
    -          The humerus fractures just above the condyles, and the distal fragment can be pushed and twisted. This poses a risk to the brachial artery, which if damaged, can result in severe limb ischaemia.
    o   You should always check the radial pulse, which checks the integrity of the brachial artery!

    Fracture of the Radial Head
    -          Often caused by falling onto an outstretched hand
    -          Can be difficult to see on x-ray, particularly if it is not displaced
    -          Typical signs include:
    o   Displacement of the fat pad
    o   Effusion of the elbow
    o   Decreased range of elbow movement – particularly extension – which can last for several months
    Colle’s Fracture – distal radial fracture
    -          Results from falling onto dorsiflexed (outstretch) hands, with resultant posterior displacement of the wrist. The term colle's fracture however is however sometimes applied to almost any fracture of the distal radius.
    -         Management - if undisplaced, cast alone is usually successful. slight displacement and angulation can be treated with closed reduction (manipulation of the fracture without surgery, with plenty of pain releif!). Large displacements require surgery to correct, and often there is some form of internal fixation. rarely, external fixation is also used.
    -         Complications - 
    Colle's Fracture
     Colle's fracture - almostadoctor.com - free medical student revision notes
    Smith’s Fracture – distal radial fracture
    -          The reverse of Colle’s – results from falling onto a palmar flexed wrist

    Chauffer’s fracture – distal radial fracture
    -          Fracture of the styloid of the radius, usually due to compression of this against the scaphoid
    -          Caused by falling onto a dorsiflexed hand
    -          Gets its name from the fractures seen when Chauffer’s, when cranking a car’s engine would break their wrist when the engine backfired.
    Scaphoid Fracture
    -          The scaphoid bone articulates with the distal end of the radius.
    -          Nearly always the result of falling onto a dorsiflexed (outstretched) hand
    -          Often the diagnosis is missed as it can be very difficult to see on x-ray
    o   May be misdiagnosed as a ‘sprained wrist’
    -          Patients will have a feeling of ‘fullness’ or pain in the anatomical snuffbox – the depression between the tendons of the thumb when the thumb is fully extended and abducted
    -          Treatment
    o   Immobilisation of the joint is necessary. Without this, the scaphoid may not unite properly, and there can be necrosis of the scaphoid, resulting in prolonged pain and weakness in the wrist.

    Fracture of the Elbow
    -          Often result from falling on an outstretched arm
    -          Can be very difficult to see on x-ray. Look for the posterior fat pad sign which is visible as a slight dark patch behind the elbow, on the lateral view.
    o    Fracture may be more visible after 10 days, so consider re-x-ray
    -          Pain relief is important for the first couple of weeks, but it is really important to mobilise the joint early to prevent permanent loss of extension. Patients should be encouraged to use the affected arm as much as pain allows and as soon as possible.


    Notes by Tom Leach
    GIM Residents Core Reading

    GIM Residents Core Reading

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    Internal Medicine: Toronto Notes 2002

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    Internal Medicine: Toronto Notes 2002
     
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