Pathophysiology of Diabetic Foot for Nurses | Bobr.ai

Pathophysiology of Diabetic Foot

How Diabetes Affects the Feet & Its Complications

Jawaher Almaskari

Podiatrist | Seeb Polyclinic

Presented for Health Centre Nurses

What is Diabetic Foot Disease?

A serious complication of diabetes affecting the feet

Includes: neuropathy, poor circulation, ulcers, infections & amputation

15–25%

Lifetime risk of foot ulcer in diabetics

50–70%

Ulcer recurrence rate within 5 years

Up to 85%

of amputations are preceded by a foot ulcer

How Does Diabetes Damage the Feet?

4 Main Pathophysiological Mechanisms

Metabolic Dysfunction

Hyperglycemia damages nerves and blood vessels

Nerve Damage (Neuropathy)

Loss of feeling, weakness, dry skin

Blood Vessel Disease (Angiopathy)

Poor circulation, atherosclerosis

Immune Impairment

Reduced ability to fight infections

These 4 factors together lead to

Diabetic Foot Ulcers, Infections & Amputation

Diabetic Neuropathy

Loss of Feeling

SENSORY NEUROPATHY

Loss of protective sensation — patient can't feel pain, heat, pressure → injuries go unnoticed

MOTOR NEUROPATHY

Muscle weakness → foot deformities (claw toes, hammer toes) → abnormal pressure points

AUTONOMIC NEUROPATHY

Dry skin, no sweating → cracked skin, fissures → entry point for infection

Neuropathy is the underlying cause in >60% of diabetic foot ulcers

Poor Blood Flow — Diabetic Angiopathy

Can lead to: ischemia → gangrene → amputation

Signs to watch for

Absent foot pulses, cold feet, pale/blue skin, pain on walking

How Ulcers Develop — The Pathway to Ulceration

Diabetes → Neuropathy

Nerve damage causes a profound loss of sensation in the feet.

Pressure & Deformities

Abnormal foot pressure and structural changes cause callus formation.

Subcutaneous Bleeding

Callus builds up over time, triggering bleeding under the skin.

Foot Ulcer

Skin breaks down entirely, exposing deeper tissues.

Minor trauma (e.g., tight shoes, walking barefoot) → Unnoticed due to neuropathy → Foot Ulcer

The patient often does NOT feel pain — which is why regular foot inspection is critical!

Diabetic Foot Infections

High blood sugar impairs white blood cell function

Poor circulation limits antibiotic delivery to tissues

Loss of sensation = infections go unnoticed

Skin cracks and ulcers = entry points for bacteria

Most common: Staphylococcus aureus

MRSA found in up to 30% of cases

Severe infections can reach bone (Osteomyelitis)

⚠️ Infection in a diabetic foot = EMERGENCY — can spread rapidly to bone and blood, leading to amputation

Charcot Foot

A Special Complication

What is it?

A progressive bone and joint destruction in the foot

Caused by: neuropathy + increased blood flow + repeated minor trauma

Bones weaken and fracture without pain

What does it look like?

Red, hot, swollen foot (can mimic infection)

Midfoot collapse → 'rocker-bottom' foot deformity

Foot becomes very deformed over time

Why is it important for nurses to know?

Easy to miss — patient has NO pain due to neuropathy

Must be differentiated from infection

Early detection and offloading prevents severe deformity

KEY SIGN:

Hot, swollen foot in a diabetic patient with neuropathy = suspect Charcot foot

Risk Stratification — Who Is at High Risk?

IWGDF Risk Categories for Clinical Screening

Risk Level

Description

Check Frequency

0 — Very Low

No neuropathy, no PAD

Once a year

1 — Low

Neuropathy OR poor circulation

Every 6–12 months

2 — Moderate

Neuropathy + poor circulation OR foot deformity

Every 3–6 months

3 — High

History of ulcer or amputation + neuropathy/PAD

Every 1–3 months

LOPS = Loss of Protective Sensation (tested with 10g monofilament)

PAD = Peripheral Artery Disease (check foot pulses)

All diabetic patients need annual foot screening — even those with no symptoms!

The Nurse's Role — Foot Screening Checklist

What to LOOK for

Skin colour and temperature changes

Callus, blisters, fissures or wounds

Nail problems (ingrown, fungal, thickened)

Foot deformities (claw toes, bunions)

Swelling or redness

What to TEST

<span style="color: #FFFFFF; font-weight: 600;">Sensation:</span> 10g monofilament test (3 sites per foot)

<span style="color: #FFFFFF; font-weight: 600;">Pulses:</span> Dorsalis pedis and posterior tibial

<span style="color: #FFFFFF; font-weight: 600;">Footwear:</span> Check inside shoes for rough edges

<span style="color: #FFFFFF; font-weight: 600;">Skin moisture:</span> Dry vs normal

<span style="color: #FFFFFF; font-weight: 600;">Ask about:</span> Numbness, tingling, pain on walking

Refer to podiatry if:

ulcer present, LOPS confirmed, absent pulses, Charcot suspected, or foot deformity found

Patient Education

Key Messages for Diabetic Patients

👣

Inspect both feet daily — look between the toes

🚿

Wash feet daily in warm water (below 37°C), dry well between toes

👟

Never walk barefoot — indoors or outdoors

🩺

Wear properly fitting shoes — check inside before putting on

🧴

Moisturize dry skin — but NOT between toes

✂️

Cut toenails straight across

🌡️

Never use hot water bottles on feet

🏥

Report any wound, blister or color change immediately

Early reporting saves limbs. A small cut can become a major problem in a diabetic patient.

Key Takeaways

Diabetes causes nerve damage, poor circulation and immune impairment — all affecting the feet

Neuropathy = patient feels NO pain → injuries go unnoticed → ulcers develop

Poor blood flow = wounds heal slowly → risk of gangrene and amputation

All diabetic patients need annual foot screening — even without symptoms

Early detection and prompt referral can prevent amputation

Questions?

Contact Jawaher Almaskari — Podiatrist, Seeb Polyclinic