Subdural Hematoma: When to Cut

Subdural Hematoma: When to Cut

Subdural hematoma is a common neurosurgical problem. A subdural usually occurs in patients with significant brain atrophy, such as the elderly or alcoholic. Even minor trauma can injure the bridging veins between the brain and the dura. Bleeding into the subdural space can occur rapidly, causing death in a matter of hours, or gradually over a period of weeks. The surgical management depends on whether the hemorrhage is acute or chronic.

Acute Subdural Hematoma

An acute subdural may result from trauma or in a patient on antiplatelet or anticoagulant drugs. Symptoms often include headache, hemiparesis or alteration of consciousness like agitation, lethargy, or coma. If the acute subdural is small, it can be managed non-surgically. Antiplatelet drugs are stopped, and coagulation is corrected. Careful clinical observation is imperative. The subdural may expand as it becomes chronic, as the osmotic effect of the blood products draws free CSF into the subdural space. All this to say, if a small, acute subdural isn’t surgical today, it may be in two weeks!

Here a moderate sized, acute subdural is seen. You will notice a hyperdense (white) mass over the cortical surface of the brain (arrow), with effacement of the gyral pattern adjacent to the subdural, along with asymmetry of the lateral ventricles and midline shift.

Acute subdural hematoma

This patient was taken to surgery for a craniotomy. In the craniotomy, a large section of the skull was removed. This is called “turning a flap.” It allows the evacuation of the blood clot. At surgery, the clot was so tenacious it could be picked up with forceps. This, by the way, is the reason that an acute subdural cannot be drained with a bur hole. The blood is congealed. It cannot be drained with a bur hole any more than a cup of Jello can be eaten with a straw: it is solid. Air is introduced into the head at the time of surgery. It appears jet black on CT (arrow).

Acute subdural hematoma post op

Chronic Subdural Hematoma

On CT, a chronic subdural is hypodense (dark). It represents old blood in a liquid state. How old is old? It takes about two weeks for an acute subdural to liquefy, and the CT appearance will evolve from hyperdense to hypodense as the hemorrhage becomes chronic. Symptoms include headache on the same side as the subdural. Hemiparesis may be mild or well compensated as weakness occurs gradually. Many patients experience hemiparesis as gait imbalance, or veering to one side. As the patient worsens, frank lethargy or coma may ensue.

Here is a chronic, subacute subdural hematoma. You see a hypodensity over the cerebral convexity anteriorly (double arrow), with a hyperdense component posteriorly (arrow). There is effacement of the gyral pattern, ventricular asymmetry and midline shift.

Subacute chronic subdural hematomaChronic subacute subdural hematoma with labels

This patient was taken to the operating room for bur-hole evacuation of the subdural. The liquefied blood was removed with a simple bur hole. Going back to the Jello analogy: If you leave Jello at room temperature, it turns to liquid; in this case you CAN drink it with a straw. Or drain a chronic subdural with a bur hole!

Here you can see postoperative air in the head (jet black, see arrow), with a mix of residual chronic and subacute blood, with improved mass effect. A drain is present (double arrow).

Chronic subdural hematoma post opChronic subdural hematoma post op with labels

To summarize, an acute subdural is a life threatening emergency, often requiring craniotomy within hours. The chronic subdural can be life threatening as well, but over a period of weeks, often treated with simple bur hole drainage.

On Call Pitfalls

On-Call Pitfalls

Things that Kill. Things that Bother.

Calls to the neurosurgery group can be divided into two groups: things that kill and things that bother. Listening for conditions that may become life threatening is a skill that comes with experience. What is “experience?” Paying attention to the things that have happened, often informed by mistakes you have made in the past!

Things that kill

MI. Specifically myocardial infarction in the post operative patient. Surgery is a stress to the body, and the patient with atherosclerotic coronary disease, for example, can be pushed over the edge simply from the physical impact of the surgical event. A cardiac event is suggested by any combination of chest pain, with radiation to the jaw or arm, with diaphoresis, with shortness of breath. Be quick to order a 12-lead EKG, cardiac enzymes, and pulse ox. If you wonder if the patient may be unstable, call the Rapid Response team for an immediate evaluation.

PE. Pulmonary embolism is characterized by chest pain around the ribs, diaphragm, or back, with shortness of breath, tachypnea, and anxiety about breathing, worse with lying, better sitting and leaning forward. Evaluate with pulse ox, ABG, chest x-ray, CT-Angiogram of the chest, and labs. Definitely call a Rapid Response whenever there is respiratory distress.

DVT. Here are the classic hallmarks of DVT: a painful, red, swollen, hot extremity. This is a little tricky to sort out on the neurosurgery service, since many of our patients have pain in an extremity to start with! So when you are called for pain in a leg or an arm, always ask: Is it swollen, red, and hot compared to the other? Order an ultrasound of that extremity to look for DVT, and unless you are sure it is not a DVT, remove the sequential compression device from the leg and keep the patient on bed rest. If a DVT is present, you’ll need to consider anticoagulation and the placement of an IVC filter.

CVA. Acute ischemic stroke presents with new-onset brain symptoms. Weakness or numbness on one side of the body, facial droop, slurred speech, confusion, and vertigo are all signs of a stroke. These symptoms are usually painless, and the patient almost always discounts their significance. Family members will often be the first to mention the changes. Any new onset stroke symptoms require an immediate CT of the head. Even in acute stroke, though, this is expected to be *normal* unless the stroke is hemorrhagic! Sometimes a follow up MRI is ordered with diffusion weighted images to prove the ischemic event. Other diagnostic steps include pulse ox, 12-lead EKG, labs including chemistry, CBC, lipid profile, and HbA1c. Risks and benefits of aspirin therapy can be weighed carefully in the post op neurosurgical patient.

Spinal cord compression and cauda equina syndrome. An epidural hematoma after a spinal procedure is a neurosurgical emergency. In the cervical spine this can follow anterior or posterior surgery. The hematoma compresses the cord causing severe local pain along with weakness, numbness, and spasticity in the extremities, with increased reflexes and sustained clonus. In the lumbar spine an epidural hematoma may compress the cauda equina causing severe local pain and numbness in the saddle region or in the legs, with weakness and depressed reflexes. Either case is a neurosurgical emergency and must be evaluated with immediate plain x-ray to visualize the bone structure and urgent MRI to image post op fluid collections, CSF, and the neural structures.

Drug allergy. A true drug allergy can be a life threatening emergency with anaphylaxis or hemodynamic shock. The lip swelling of angioedema or a macula-papular rash on the chest and trunk can herald an allergic reaction. Treatment begins with stopping the offending agent, a real trick since you usually don’t know which drug is the culprit! So you go with percentages: phenytoin and antibiotics are well known for causing allergic reactions. The next step of treatment is steroids and antihistamines to suppress the body’s allergic response. Above all, you must be mindful to protect the patient’s airway at all times.

Things that Bother

The vast majority of your calls will be for issues of comfort. I’m not minimizing these, but they occupy a different level of urgency. They are important in the patient’s recovery in that they can be obstacles to the patient’s physical progress. Here are the most common.

Pain. An inordinate amount of pain can signal an urgent problem like an epidural hematoma in the immediate post op patient, or infection days to weeks after surgery. After you have ruled out worrisome causes of pain, treat it using the standard drugs in your armamentarium: narcotics, muscle relaxants, anticonvulsants (like gabapentin), antidepressants (like amitriptyline), and sometimes a short course of steroids. Physical options include an ice pack to the surgical site. The PT/OT can instruct the patient in proper body mechanics to reduce pain with movement. The main idea is to control the pain well enough to allow physical progress in recovery.

Nausea. Pain can be nauseating, and the drugs used to treat pain can be nauseating! Nausea may reflect a post operative ileus that can occur after exposure for anterior lumbar surgery. Diagnostic evaluation with KUB can demonstrate an ileus. For the nauseated patient, limit the diet to ice chips or clear liquids until the gut is in better spirits.  Antiemetics and prokinetics are the medications most useful to keep on board, and in severe nausea these can be ordered around the clock for a period as a preventative. A physical technique to help prevent vomiting is slow, steady breathing. If vomiting is imminent, prevent aspiration by having the patient in a side-lying position or elevate the head of bed.

Constipation. There, I’ve said it! This is the number one complication of any hospitalized patient, and you will soon become an expert in preventing and treating constipation. Keep in mind that managing constipation in the *hospitalized* patient is different from the primary care setting. You’ll use docusate (Colace) in all hospitalized patients. Be quick to add polyethylene glycol (Miralax) and senna (Senokot) nightly for mild constipation. Bisacodyl functions like a stick of dynamite in the gut, and you’ll prefer the suppository route to “put the medicine right where it needs to work.” An enema is another option.

Itching. Itching can be an annoying but benign side effect of some medications like narcotics, or it may be a much more significant signal of an allergic reaction. For mild itching, a systemic antipruritic like diphenhydramine or hydroxyzine is useful. I avoid topical antihistamines and steroids because I don’t want my patient slathering medicine around a surgical incision. Blisters will appear with Stevens-Johnson syndrome, which is a life threatening emergency.

Call for help

As a neurosurgery beginner, you won’t have the experience, so learn from the experience of others. Keep your handbooks handy, both neurosurgery and medicine. Be quick to call your attending physician or a seasoned peer for advice. There are dangers and pitfalls lurking everywhere. As the saying goes: Learn from the mistakes of others—you won’t live long enough to make them all yourself.