Neobook — clinical reference

Introduction
Describe The Pain Thoroughly
Issues To Consider In The History
Clinical Examination
Evaluation Priorities
Differential Diagnosis

Context: Casualty

Introduction

Sudden onset of severe pain in a limb is uncommon and should alert you to a range of possible diagnoses. It is not "one of those things that gets better by itself." Apply your mind and make a rapid, accurate diagnosis; decide if urgent intervention is needed.

Try to decide if this is a brand new symptom, out of the blue, or if it reflects a progression of long standing disease. Is this an acute problem or an exacerbation of a chronic condition?

Describe the Pain Thoroughly

Define the presenting complaint
Location and radiation	Where is it, and where does it radiate to? In the foot, the calf or the back of the thigh? Is it pain radiating along a neurological distribution?
Temporal elements	The onset, frequency, and duration of the pain are helpful features Is there a history of arterial or venous or spinal claudication?
Quality	Is there any parathesia or dysaesthesia? - suggestive of neuropathy
Severity	The severity of the pain generally is related to the severity of the disorder, especially if acute in onset Excruciating = arterial occlusion, compartment syndrome High intensity = DVT Moderate = cellulitis
Precipitants or ameliorating factors	Identify what precipitates or improves the pain Is there a history of trauma, or precedent claudication? Can the patient bear weight? Inability to do this often implies either bone or joint pathology

Issues to Consider in the History

This allows you to consider the other causes, and contextualise the patient's fitness for intervention

Cardio-respiratory symptoms	Is the patient a vasculopath? Is there an arrythmia or CCF? Cough, shortness of breath, orthopnea, exertional dyspnea, angina = pulmonary or cardiac origin of an embolus?
Past medical history	Risk factors for DVT? Previous surgery or trauma? Any back surgery or connective tissue disease or gout? Is the patient diabetic or HIV+ve?
Medication history	Describe a comprehensive medication list, including over the counter medications
Precipitants & other aetiological factors	Is the patient a smoker? Travel history = possible DVT Family Hx of hypercoagulable states

Clinical Examination

General examination	Pyrexia = cellulitis Edema = CCF, arrythmia Peripheral neuropathy Signs of CT disorder, gout or arthropathy
Vascular examination	Does the patient have clinical signs of PVD? Examine all pulses carefully, check blood pressure and do a proper cardiac evaluation Auscultate for bruits, and feel for irregular pulse rhythm
Limb examination	Compare both limbs carefully Look - erythema, pus or bullae, puncture marks, signs of PVD, scars or ulcerations, chronic lymphedema or pigmentation? Any areas of focal swelling, trauma or bruising? Is the leg swollen? If in doubt take a tape measure and compare the calf circumferences of each leg. Is there any tissue loss or frank gangrene? Feel - is it hot or cold? Is there focal tenderness to palpation in a specific compartment? Is it edamatous? Is there fluctuance or crepitus? Do the muscles feel soft and normal or woody and stiff? Is there a palpable mass? Do a neurological evaluation of the limb - is there movement? Signs of peripheral neuropathy?

Evaluation Priorities

How sick is the patient?	Do I need to start a resuscitation protocol? Sometimes needed in severe sepsis or with major cardiac dysfunction
How bad is the pain?	Give adequate analgesia, typically parenteral opiates
What is the diagnosis?	Most of the diagnoses are obvious clinically, with little need for extensive and complex investigations. When suspecting a vascular occlusion, checking for blood flow with an arterial Doppler is extremely helpful
Does the patient OBVIOUSLY need an urgent intervention?	Whilst most common cause of limb pain are treated medically and can be evaluated within 24-48 hours, there are 3 less common conditions that need URGENT intervention: 1. Acute arterial occlusion 2. Compartment syndrome 3. Necrotising fasciitis An acutely ischaemic limb is critically urgent - if blood flow is not re-established within 4-6 hours the chances of major morbidity or limb loss are high! Get on with it! Alert your seniors.

Differential Diagnosis

Common causes
Condition	Clinical Features	SI	Urgent Surgery
Cellulitis	1-2 days of pain and swelling, pyrexial red swollen, hot limb	WCC++	No
DVT	Short Hx, swelling, pain in back of the calf, swollen +++ may have risk factors for DVT	N WCC, +Ddimer, leg compression US	No
Chronic ischemia with tissue loss and sepsis	Vasculopath or diabetic, tissue loss with osetitis or spreading sepsis. Sensation may be absent due to longstanding neuropathy	Elevated WCC, x-ray foot may show osetitis and bone destruction	Yes, within 12-24 hours, typically amputation. A few may be candidates for vascular reconstruction
Don't want to miss
Acute arterial occlusion	Very short history, extreme pain. Cold, pulseless limb, usually from embolic cardiac source	Poor or no arterial flow on doppler. May have cardiac source of emboli	Yes - Immediate embolectomy
Compartment syndrome	Short Hx, usually post trauma or surgical. Pain in muscle group, with tense swelling. Pulses usually present	Clinical diagnosis	Yes - Urgent fasciotomy
Necrotizing infection	Extreme pain, systemically very unwell, visible necrotic tissue, crepitus	WC +++, organ dysfunction	Yes, urgent debridement
Septic arthritis	Extremely tender joint. Hot and swollen. Unable to bear weight	WCC ++++	Yes, urgent wash out
Less common diagnoses
Pathological fractures	Unable to bear weight. No or minor trauma. Bone disease	XR	No
Ruptured Baker's cyst	Pain and swelling back of calf, or popliteal fossa. Often misdiagnosed as DVT	US	No
Discogenic pain	Severe radiating pain into the leg or foot. Often worse when straining or changing position	MRI	Usually mx conservatively. Surgery only with impending spinal cord compression
Gout / arthropathy	Extremely tender JOINT - typically 1st toe, but may involve others, may have preceding episodes of gout	N WCC, elevated urate levels	No
Chronic osteitis	Long standing pain, with exacerbation. Sinus discharging pus	XR or MRI reveals bone destruction	Elective surgery
Sarcoma	Bone sarcoma often has pain as the presenting symptom, before clinical signs are evident	XR, MRI, biopsy	No, elective surgery after full work up