Differentials
Rhinosinusitis
SIGNS / SYMPTOMS
Sinusitis pain to palpation is localised to the para-nasal and frontal sinuses. Pain from rhinosinusitis is usually worse when bending forwards.
TMDs usually involve the temporomandibular joint region and possibly the temporal and masseteric regions.
INVESTIGATIONS
Otoscopic examination may reveal an abnormality such as effusion or obstruction.
Evaluation is best performed by a dentist when dental pathology is suspected.
Pericoronitis
SIGNS / SYMPTOMS
Joint clicking is absent; breath may be malodorous; pericoronal tissues around an impacted wisdom tooth may be inflamed and erythematous.
INVESTIGATIONS
Examination reveals that mandibular posterior teeth (especially the third molars) are erupting.
Chronic headache
SIGNS / SYMPTOMS
Joint clicking is absent.
Pain is not cyclic.
INVESTIGATIONS
There are no differentiating tests.
Dental pain
SIGNS / SYMPTOMS
Hot/cold testing of teeth indicates extreme sensitivity.
Tapping the tooth elicits pain.
Joint clicking is absent.
INVESTIGATIONS
Dental x-rays may reveal peri-apical pathology.
Evaluation is best performed by a dentist when dental pathology is suspected.
Systemic lupus erythematosus
SIGNS / SYMPTOMS
Clinical manifestations of systemic lupus erythematosus may be present including malar rash or discoid lupus (thick, red, scaly patches on the skin).
Small joints of the hand and wrist are usually affected, although any joint is at risk.
Other presenting features include pericarditis, myocarditis, and endocarditis; pulmonary manifestations; autoimmune hepatitis; and glomerulonephritis.
INVESTIGATIONS
Markers of systemic disease: anaemia, thrombocytopenia, neutropenia, deranged LFTs.
Positive antinuclear antibody, anti-double stranded DNA antibody and anti-Smith antibody on serological testing.
Rheumatoid arthritis
SIGNS / SYMPTOMS
Patients with rheumatoid arthritis may have other joint involvement, particularly symmetrical small joint polyarthritis in the hands, chiefly affecting the metatarsophalangeal joints and sparing the distal interphalangeal joints.
Patients with acute rheumatoid arthritis may also feel generally unwell with fatigue and low mood.
INVESTIGATIONS
In rheumatoid arthritis, ESR and CRP are often abnormal and rheumatoid factor and anticyclic citrullinated (anti-CCP) antibodies are usually positive.
Typical rheumatoid arthritis erosive changes may be seen on x-ray, MRI, or ultrasound.
Giant cell arteritis
SIGNS / SYMPTOMS
Patients typically have pain and tenderness over the temporal artery, which may occur with amaurosis fugax and loss of vision.
Pain resolves within 3 days of high-dose corticosteroid treatment.
INVESTIGATIONS
Duplex scanning of temporal arteries may reveal thickening of the arterial wall.
Erythrocyte sedimentation rate >100 mm/hour.
CRP is usually elevated.
Biopsy shows giant cell arteritis.
Neuralgias
SIGNS / SYMPTOMS
Joint clicking is usually absent.
Facial pain is elicited by touching a trigger point.
INVESTIGATIONS
Clinical diagnosis.
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