Stage 4 Bedsores: The Most Serious Pressure Injury

You see a wound on your loved one that goes deeper than skin. It is open, dark, and the tissue inside does not look like anything you have seen before. You may be able to see bone or muscle. Approximately 60,000 deaths each year in the United States are directly caused by pressure injuries [PMC7949299]. A stage 4 bedsore is the most dangerous form of this injury, and it should never happen without explanation.

A stage 4 bedsore means tissue has been destroyed down to the bone. If your loved one developed this injury in a nursing home, a free case evaluation can help you understand your legal options.

Find Out If It Was Preventable

What Is a Stage 4 Bedsore?

The NPIAP defines a stage 4 pressure injury as full-thickness skin and tissue loss. Fascia, muscle, tendon, ligament, cartilage, or bone is exposed or can be felt directly in the wound [NPIAP / PMC5098472].

In plain language, this means the wound has eaten through every layer of skin and into the structures underneath. You may see yellow, brown, or black tissue in the wound. This dead tissue is called slough (yellow or tan) and eschar (black or brown). It must be removed before doctors can even measure how deep the damage goes [NPIAP / NBK557868].

Stage 4 wounds often have two features that make them worse than they appear from the outside:

• Undermining: The wound is wider underneath the skin than at the surface. Tissue is being destroyed sideways beneath what looks like an intact skin edge [NPIAP].
• Tunneling: Narrow passages extend from the wound opening into surrounding tissue, creating pockets where bacteria grow [NPIAP].

Sacral stage 4 wounds – among the most common locations in bed-bound nursing home residents – can extend five centimeters or more in depth [NPIAP / NBK557868].

A stage 4 pressure ulcer is also called a stage 4 pressure injury under the updated NPIAP terminology. Regardless of the term your facility uses, the severity is the same. This is the deepest and most dangerous form of bedsore that can develop.

Warning Signs of a Stage 4 Bedsore

• A deep, open wound where you can see muscle, bone, or tendon
• Yellow, brown, or black tissue inside the wound
• A foul smell coming from the wound area
• Wound edges that appear rolled inward or undercut
• Heavy drainage or fluid leaking through bandages
• Skin around the wound that is warm, swollen, or red
• Your loved one has a fever or seems confused or more lethargic than usual
• The wound appears to be getting larger despite treatment

When Is a Nursing Home Responsible?

Federal law requires nursing homes to prevent pressure injuries in residents who do not have them at admission – unless the facility can prove the injury was clinically unavoidable [42 CFR 483.25(b)]. The burden of proof is on the facility, not on the family.

A stage 4 bedsore does not happen overnight. It progresses through Stage 1, Stage 2, and Stage 3 before reaching this point. At each stage, the nursing home had an opportunity to intervene.

That means a stage 4 wound represents repeated failures: failure to assess risk, failure to reposition, failure to provide proper nutrition, failure to treat the wound when it was smaller. CMS considers a facility-acquired stage 4 pressure injury a serious regulatory event that can trigger the highest enforcement category.

The facility must be able to show that it performed a risk assessment, built a care plan, followed the plan, and adjusted it when the wound did not improve. If it cannot produce this documentation, the injury is presumed preventable.

Ask the nursing home: “Can you show me the wound care records, repositioning logs, and care plan updates for every week since this wound first appeared?”

A stage 4 wound in a nursing home resident is one of the most serious regulatory findings CMS can make. It can result in substantial deficiency citations and, in some cases, may trigger the highest enforcement category. The significance of this injury cannot be overstated – for the resident, for the family, and for the facility’s legal obligations.

What Happens If a Stage 4 Bedsore Goes Untreated

The consequences of a stage 4 bedsore are severe and well-documented.

Mortality. Patients with Stage 3 and 4 wounds have a 2.4 times higher mortality risk (hazard ratio 2.41) compared to patients without pressure injuries [PMC7949299]. For an elderly resident with a stage 4 wound, a concurrent infection, and underlying medical conditions, the overall mortality rate approaches 50 percent [PMC7949299].

Osteomyelitis. Approximately one-third of stage 4 pressure injuries progress to osteomyelitis – a bone infection [PMC6824522]. Once bone is exposed, bacteria from the wound gain direct access to skeletal tissue.

Amputation. Stage 4 pressure injuries carry a high likelihood of requiring amputation. Published data show a 63 percent amputation-free survival rate at one year – meaning more than one in three patients may face amputation [PMC11604378].

Treatment failure. Standard nonsurgical care rarely closes a stage 4 wound. Only 5 percent of these wounds close within eight weeks under conservative treatment [PMC10144322]. Even with surgery, flap reconstruction carries a complication rate of 59 to 73 percent and a recurrence rate of 29 percent [PMC10144322].

Extended suffering. The mean treatment duration for stage 4 wounds has exceeded 29 months without achieving full closure [PMC10144322]. That is more than two years of wound care, pain, and reduced quality of life.

Surgical complications. When surgical flap reconstruction is attempted, 25 percent of patients experience a complication within the first 30 days. Wound dehiscence (the wound reopening) occurs in 31 percent of cases [PMC10144322]. Surgery is not a guaranteed fix. It carries significant risks of its own.

The progression from Stage 1 through Stage 2 and Stage 3 to Stage 4 is preventable at every point along the way. Each stage that passes without proper intervention makes the outcome worse. To understand how these wounds develop, see our guide on bedsore causes.