NG-365

🧠 Spinal Cord Injury

What the level predicts, the two kinds of shock that get confused, and the one true emergency.

🧬 What it is & what the level tells you

The cord with each level band and what is lost below it, and the two critical lines picked out - C4, above which she cannot breathe unaided, and T6, above which autonomic dysreflexia becomes possible. — Find the level, then read downward. And two numbers do most of the work: C4 for breathing, T6 for dysreflexia. Swipe it sideways if it is cut off, or tap to open it full size.

Damage to the cord interrupts every signal that has to pass through that point — motor down, sensation up, and the autonomic traffic in both directions.

Everything below the level of injury is affected. Everything above it is normal. Almost every question about function is answered by locating the level and looking downward.

📏 The levels worth memorizing

Level	What is lost	The clinical point
C1–C4	All four limbs, and the diaphragm	C3, 4, 5 keep the diaphragm alive. At or above C4 the patient cannot breathe unaided — ventilator.
C5–C8	Tetraplegia with some arm function	Diaphragm works but the cough is weak — watch for retained secretions.
T1–T6	Paraplegia; trunk control poor	At or above T6, autonomic dysreflexia becomes possible.
T6–T12	Paraplegia, better trunk control	Independent wheelchair use realistic.
L1–S5	Leg weakness; bowel, bladder, sexual function	Bracing and walking may be possible.

Two numbers do a lot of work. C4 — above it, no breathing. T6 — above it, autonomic dysreflexia. If a stem gives you a level, check it against both immediately.

🧪 Complete or incomplete

Complete — no motor or sensory function below the level, including the lowest sacral segments.
Incomplete — some function is preserved, so some recovery is possible.
The true extent cannot be judged until spinal shock resolves — which is why early prognosis is guarded.

⚡ The two shocks — the classic mix-up

Spinal shock and neurogenic shock are different problems that happen at the same time and get confused constantly. One is about reflexes. The other is about blood pressure.

	Spinal shock	Neurogenic shock
What it is	Temporary loss of all reflex activity below the injury	Loss of sympathetic tone → circulatory failure
Signs	Flaccid paralysis, no reflexes, no sensation, bladder and bowel atonic	Hypotension + bradycardia + warm, dry, flushed skin
Level	Any level	Usually T6 and above
Lasts	Days to weeks; reflexes return, often hyperactive	Up to several weeks
Treatment	Supportive; wait it out	Fluids, vasopressors, atropine for the bradycardia

The discriminator that decides the question. Every other kind of shock is fast heart rate, cold clammy skin — the body compensating. Neurogenic shock cannot compensate, because the sympathetic pathway is cut.

Hypotension with a slow pulse and warm dry skin is neurogenic shock. Hypotension with a fast pulse and cold clammy skin is hypovolemic — go looking for bleeding.

🚨 Autonomic dysreflexia — a true emergency

This is the one that kills. Uncontrolled hypertension in a patient with an injury at or above T6. Blood pressure can reach stroke range within minutes.

🦠 Why it happens

1 · A triggerSomething noxious below the injury — usually a full bladder

2 · Sympathetic surgeThe signal cannot reach the brain, so reflex vasoconstriction runs unopposed

3 · BP climbsSevere hypertension

4 · Half a responseThe brain slows the heart, but cannot stop the vasoconstriction below the injury

Above the injury — the body still works

Pounding headache — usually the first complaint
Flushing and sweating of the face and neck
Nasal congestion, blurred vision
Bradycardia

Below the injury — vessels clamped shut

Skin pale, cold and dry
Goose bumps
Severe hypertension — often >20–40 mmHg above their normal

🩺 What you do, in order

1. Sit the patient upright and lower the legs. Free, instant, and it uses gravity to drop the pressure. This is first.
2. Find and remove the trigger. Check the catheter for kinks; check for retention; check for impacted stool; loosen tight clothing; look for a pressure injury.
3. Monitor blood pressure every 2–5 minutes throughout.
4. Antihypertensive — a rapid-acting agent if the pressure stays high after the trigger is removed.

Do not lay the patient flat. That is the instinct with most emergencies and it is wrong here — it raises the pressure further.

The commonest trigger, by a distance, is a distended bladder. A blocked or kinked catheter is the first thing to check every single time.

💬 Living with it — what the nursing is

Acute care is airway, immobilization and blood pressure. After that, nursing is about the complications that come from not moving.

Breathing. Weak cough → retained secretions → pneumonia. Incentive spirometry, assisted cough, suction.
Skin. No sensation means no warning. Reposition on a schedule, inspect every surface daily, pressure-redistributing surface.
Bladder. Intermittent catheterisation on a schedule — and it doubles as dysreflexia prevention.
Bowel. A regular program at the same time each day; stool softeners, adequate fiber and fluid.
Clots. Immobility plus vessel changes → high DVT risk. Prophylaxis, compression, watch for a swollen calf.
Bones. Disuse osteoporosis and heterotopic ossification.
Temperature. Below the injury the body cannot sweat or shiver to regulate — the patient takes on the room's temperature.

The part that is easy to skip. Grief, altered body image, loss of role and independence, and a real risk of depression. Ask about mood directly, and involve rehabilitation, occupational therapy and peer support early rather than late.

Sources. NINDS, Spinal Cord Injury. NCBI Bookshelf StatPearls, Acute Spinal Cord Injury, Autonomic Dysreflexia and Neurogenic Shock. MedlinePlus, Spinal Cord Injuries. Public-domain and openly licensed sources; written for this site.