Differential Diagnosis A1 Final

What direction do pulleys run in the finger?

Lateral to medial, across the tendons

What direction do tendons run in the finger?

Proximal to distal

What are the general patterns of finger or thumb injury?

Hyperextension

Hyperflexion

Rotational or valgus/varus forces

Direct axial forces

What test is used for vascular screening in the hand?

Allen's test

What neural exams are used for the fingers?

Two-point discrimination

Sensory testing

Motor

muscle/tendon check

What deformities can occur in the fingers?

Heberden's nodes

Bocuahrd's nodes

Sausage fingers

Clubbing of the fingers

What are types of vascular compromise in the fingers?

Reflex sympathetic dystrophy

Raynaud's phenomenon

What are X-rays useful to diagnose in the fingers?

Rheumatoid arthritis

Osteoarthritis

Psoriatic arthritis

Which orthopedic tests are performed in the fingers?

Bunnel-littler test

Retinacular test

What injury results from Hyperextension of the thumb?

Gamekeeper's thumb

What injury results from Abduction of the thumb?

Ulnar collateral ligament damage

What injury results from Axial compression of the thumb?

Bennett's fracture

Dislocation

What injury results from hyperextension of the fingers?

Volar plate injury

Jersey finger

Dislocation

What injury results from hyper flexion of the fingers?

Avulsion of central slip

Mallet finger

What injury results from valgus stress on the fingers?

Collateral ligament damage

What injury results from varus stress on the fingers?

Volar plate injury

What injury results from Axial compression of the finger?

Capsular irritation

fracture

Why is a fracture of the finger more severe if it extends to the articular surface?

The poor healing potential of cartilage

What is the term for Avulsion fracture of the posterior distal phalanx by the extensor tendon?

Mallet Finger

What are the AKAs of Mallet finger?

baseball finger / drop finger

What is the typical history of mallet finger?

patient hit on the end of the finger usually with a ball, finger dropped into a flexed position

What are the exam findings of mallet finger?

Active extension of DIP impossible, passive extension causes tenderness of dorsum of joint

What is the treatment of mallet finger if it only affects the PIP?

Splint

When is surgery used to treat mallet finger?

if fragment is larger than ⅓ of the joint surface and >2 mm displaced or if non-reducible, or open fracture

What are the complications of mallet finger?

Dorsal skin ulcer

Nail deformity

Extensor lag

Swan neck deformity

Secondary OA

What is a type 1 mallet finger?

Tendon tear

Little retraction

What is a type 2 mallet finger?

Tendon tear

Lots of retraction

What is a type 3 mallet finger?

Bony avulsion

What is the term for Rupture of the flexor digitorum brevis tendon?

Jersey finger

What is the AKA of jersey finger?

Football finger

What is typical history of jersey finger?

Forced extension of digit on flexing finger

Which digits are more commonly affected by jersey finger?

3 and 4

What is the exam finding of jersey finger?

Inability to flex DIP

What is the term for Inability to flex the DIP?

Sweater sign

What are the complications of Jersey finger?

Unstable DIP

Secondary OA

Flexion contracture

What is the AKA for boutonniere deformity?

Central slip tear

What is the history of Boutonniere deformity?

Forced flexion injury of finger that tears extensor digitorum causing PIP joint to flex while DIP joint remains extended

What is the exam finding of boutonniere deformity?

Flexion deformity is pathognomonic with inability to move finger

What is the AKA of claw fingers?

Claw hand

What causes claw hand?

ulnar and median nerve entrapment, usually at the brachial plexus

What is the finding of claw hand at the MCP?

hyperextension

What is the finding of claw hand at the PIP and DIP?

Flexion

T or F: Claw hand is an irreversible deformity

False (since it is caused by nerve lesion, not joint deformity, it is reversible)

What are the causes of claw hand?

Nerve palsies

Charcot's joint

Compartment syndrome

How can claw hand be treated?

Contracture release

Referral to orthopedist

What is the history of solar plate injury?

Fall of outstretched finger or struck by ball hyperextends finger

What does solar plate injury mimic?

boutonniere deformity (except that the patient can move finger)

What is the history of bowler's thumb?

Usually compression of thumb on edge of ball or from any utensil or tool also overstretch into acute or chronic extension irritates ulnar digital nerve

What is the exam finding of bowler's thumb?

Tapping of the thumb causes pain and sensory symptoms into distal thumb

What is the history of trigger finger/thumb?

Insidious onset patient presents with finger getting "stuck" when trying to extend from flexed position often having to passively extend digit

What are the exam findings of trigger finger?

Active extension may be blocked

When possible, it causes a snapping action

When passive extension is possible it will snap as nodule clears under the pulley

What is the term for sprain of UCL of MCP?

Gamekeeper's thumb

What is the AKA of Gamekeeper's thumb?

Skier's thumb

What is the history of Gamekeeper's thumb?

Fall on bent back thumb such as ski pole injury where strap pulls thumb back or hit on thumb such as volleyball or basketball or football

What is the exam finding of gamekeeper's thumb?

Movement into extension or abduction is painful

What % of psoriasis patients get psoriatic arthritis?

20%

What ar the exam findings of Psoriatic arthritis?

marginal erosions in PIP and DIP joints

sharpened pencil appearance

Involvement in SI joints ad/or anterior vertebral bodies

What are the lab findings of Psoriatic arthritis?

(-) RF, may have HLA B27

What demographic is most affected by RA?

women 20-40 yo

Which joints are affected by RA?

PIP and MCP

What are the history findings of RA?

fatigue and weight loss

What are the exam findings of RA?

Joints feel warm to palpation, swollen and tender

What are the x-ray findings of RA?

Rat bite erosions in ulnar styloid process, metacarpal heads, and carpal bones

What defomrities are associated with RA?

Boutonniere

swan neck

lanois

haygarth's nodes

rheumatoid nodules

What are the Lab findings of RA?

+ RF

- HLA B27

May have elevated ESR

What nerve is entrapped in pronator teres syndrome?

Median nerve

What are the symptoms of pronator teres syndrome?

Pain and paresthesia in median nerve distribution

Impaired thumb, index finger, and middle finger flexion

Sensory disturbance over the proximal palm

Resisted forearm pronation with pain and paresthesia

Tinel's sign over the pronator muscle

What are the possible causes of pronator teres syndrome?

Fibrous band

Biceps aponeurosis fibrosis

Anomalous head of pronator teres

Nerve perforating the pronator teres

Sustained forearm supination/elbow extension

Pronator muscle hypertrophy

What is the history of pronator teres syndrome?

Repetitive pronation and wrist flexion, anterior forearm pain maybe into the thane part of the hand

What are the exam findings of pronator teres syndrome?

Decreased supination extension and ulnar deviation possible

Hypertrophy of pronator teres amy radiate into thumb and hand

What nerve is entrapped in the carpal tunnel?

Median nerve

What are the S/S of carpal tunnel syndrome?

Nocturnal hand pain and numbness

Thenar hypertrophy or atrophy

Difficulty grasping and pinching

Impaired repetitive finger motion

Which fingers are affected by carpal tunnel syndrome?

thumb - 1/2 of 4th digit

T or F: proximal palmar sensation is impaired in carpal tunnel syndrome

False

What are the potential causes of carpal tunnel syndrome?

Rheumatoid arthritis

DJD

Flexor tenosynovitis

Palmar lipomas

Repetitive wrist digit action

wrist/carpal fractures

Carpal subluxation

Congenital bony stenosis

What is the history of carpal tunnel syndrome?

Repetitive motion or prolonged compression at wrist with clumsiness and tingling

Pain and symptoms at night

What is the most common peripheral nerve injury?

Carpal tunnel syndrome

What are the exam findings of carpal tunnel syndrome?

Tinel's and phalen's may be positive

pressure sensitive

atrophy of thenar muscles is visually diagnostic

What are common comorbidities of carpal tunnel syndrome?

Pregnancy

Diabetes mellitus

Obesity

Multiple myeloma

Tuberculosis

Renal insufficiency

Hyperparathyroidism

hypothyroidism/myxedema

Amyloidosis

Psoriasis

Hemophilia

T or F: Imagining is required to diagnose carpal tunnel syndrome

False

What special tests are the gold standard of carpal tunnel syndrome?

EMG and NCV

What are the potential ddx of carpal tunnel syndrome?

Pronator entrapment syndrome*

Cervical radiculopathy

Incomplete upper plexopathy

Spondylotic myelopathy

Motor neuron disease

Syringomyelia

Polyneuropathy

Multiple sclerosis

How is carpal tunnel syndrome managed?

Change workspace to avoid extreme wrist positions

Adjust to create space in tunnel

Wrist splint at night, during activity

Surgery is rarely required and may not cure problem

What nerve is entrapped in the supinator muscle?

Radial nerve posterior interosseous branch

What are the S/S of Supinator syndrome?

Deep posterior forearm pain

Progressive fist weakness

Pain with manual compression distal to the lateral humeral epicondyle

May develop wrist drop paresis

Symptom aggravation by "wringing linen" motion

No sensory defects

What condition can supinator syndrome mimic?

lateral epicondylitis

What are the possible causes of supinator syndrome?

Repetitive stretching over frohse's arcade (supinator arch)

Radial head subluxation

Distal humeral fracture

Bursitis

RA

Monteggia fracture

fibroma/lipoma/ganglion (cystic tumor)

What is the AKA of the supinator arch?

Frohse's arcade

What nerve is entrapped in cheiralgia paresthetica?

Superficial branch of the radial nerve

What are the S/S of Cheiralgia paresethetica?

Dorsal-medial hand paresthesia (burning)

Sensory abnormalities along the dorsal wrist, thumb, and web space

Nocturnal pain

Mild cutaneous trophic changes

Positive tinel's sign

No forearm or hand atrophy

No weakness

T or F: Cheiralgia paresthetica has forearm and hand atrophy

False

What are the possible causes of cheiralgia paresthetica?

Compressive plaster cast

Tight watch strap

Tight cuffs

Intravenous infusion in forearm or wrist

Wrist osteoarthropathy

Split tendon of brachioradialis muscle

Palmar ganglion

What are the AKAs of Cheiralgia paresthetica?

handcuff neuritis / Wartenberg's syndrome

Entrapment of the superficial branch of the radial nerve between which two tendons causes cheiralgia paresthetica?

extensor carpi radialis longus (ECRL) and the brachioradialis

What are the exam findings of cheiralgia paresthetica?

Tinel's sign is often positive over the point of compression at the dorsolateral wrist

Pain may be caused by passive ulnar deviation and flexion of the wrist

Which nerve is entrapped in the tunnel of guyon?

Ulnar nerve

What are the S/S of tunnel of guyon syndrome?

Possible hypothenar atrophy

Paresis of finger abduction

Difficulty with hand grasp

Sensory abnormality over palmar aspect of medial 4th and 5th digits (dorsal is spared)

Positive reverse phalen's sign over ulnar tunnel

Sparing of flexor carpi ulnaris and flexor digitorum profundus (digits 3,4)

What are the possible causes of tunnel of guyon syndrome?

Fracture or anomaly of hook of hamate

Prolonged direct pressure, such as bike riding with racing handlebars

Fourth finger flexor tendon anomaly

Degenerative arthritis/ganglion

Pisotriquetral joint arthritis

Rheumatoid arthritis

Lipoma

Which structured make up the tunnel of guyon?

Pisiform and hook of hamate

What runs through the tunnel of guyon?

Ulnar artery and nerve