science

Priapism

Priapism is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Priapism rather than just read about it. In short: Priapism is a condition in which a penis remains erect for hours in the absence of stimulation or after stimulation has ended. There are three types: ischemic (low-flow), nonischemic (high-flow), and recurrent ischemic (intermittent).

Key takeaways

Priapism belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Priapism to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Priapism from memory before moving on to harder problems.

Reference excerpt

Priapism is a condition in which a penis remains erect for hours in the absence of stimulation or after stimulation has ended. There are three types: ischemic (low-flow), nonischemic (high-flow), and recurrent ischemic (intermittent). Most cases are ischemic. Ischemic priapism is generally painful while nonischemic priapism is not. In ischemic priapism, most of the penis is hard; however, the glans penis is not. In nonischemic priapism, the entire penis is only somewhat hard. Very rarely, clitoral priapism occurs in women. Sickle cell disease is the most common cause of ischemic priapism. Other causes include medications such as antipsychotics, SSRIs, blood thinners and prostaglandin E1, as well as drugs such as cocaine. Ischemic priapism occurs when blood does not adequately drain from the penis. Nonischemic priapism is typically due to a connection forming between an artery and the corpus cavernosum or disruption of the parasympathetic nervous system resulting in increased arterial flow. Nonischemic priapism may occur following trauma to the penis or a spinal cord injury. Diagnosis may be supported by blood gas analysis of blood aspirated from the penis or an ultrasound. Treatment depends on the type. Ischemic priapism is typically treated with a nerve block of the penis followed by aspiration of blood from the corpora cavernosa. If this is not sufficient, the corpus cavernosum may be irrigated with cold, normal saline or injected with phenylephrine. Nonischemic priapism is often treated with cold packs and compression. Surgery may be done if usual measures are not effective. In ischemic priapism, the risk of permanent scarring of the penis begins to increase after four hours and definitely occurs after 48 hours. Priapism occurs in about 1 in 20,000 to 1 in 100,000 males per year.

Classification Priapism is classified into three groups: ischemic (low-flow), nonischemic (high-flow), and recurrent ischemic. The majority of cases (19 out of 20) are ischemic in nature. Some sources give a duration of four hours as a definition of priapism, but others give six. Per the University Hospital Schleswig Holstein, "The duration of a normal erection before it is classifiable as priapism is still controversial. Ongoing penile erections for more than 4 hours can be classified as priapism."

In women Priapism in women (continued, painful erection of the clitoris) is significantly rarer than priapism in men and is known as clitoral priapism or clitorism. It is associated with persistent genital arousal disorder (PGAD). Only a few case reports of women experiencing clitoral priapism exist.

Signs and symptoms

Complications Because ischemic priapism causes the blood to remain in the penis for unusually long periods of time, the blood becomes deprived of oxygen, which can cause damage to the penile tissue. Such damage can result in erectile dysfunction or disfigurement of the penis. In extreme cases, if the penis develops severe vascular disease, the priapism can result in penile gangrene.

Low-flow priapism Causes of low-flow priapism include sickle cell anemia (most common in children), leukemia, and other blood dyscrasias such as thalassemia and multiple myeloma, and the use of various drugs, as well as cancers. A genome-wide association study on Brazilian patients with sickle cell disease identified four single nucleotide polymorphisms in LINC02537 and NAALADL2 significantly associated with priapism. Other conditions that can cause priapism include Fabry's disease, as well as neurologic disorders such as spinal cord lesions and spinal cord trauma (priapism has been reported in people who have been hanged; see death erection). Priapism can also be caused by reactions to medications. The most common medications that cause priapism are intra-cavernous injections for the treatment of erectile dysfunction (papaverine, alprostadil). Other medication groups reported are antihypertensives (e.g. Doxazosin), antipsychotics (e.g., chlorpromazine, clozapine), antidepressants (most notably trazodone), anti-convulsant and mood stabilizer drugs such as sodium valproate. Anticoagulants, cantharides (Spanish Fly) and recreational drugs (alcohol, heroin and cocaine) have been associated. Priapism is also known to occur from bites of the Brazilian wandering spider.

High-flow priapism Causes of high-flow priapism include:

blunt trauma to the perineum or penis, with laceration of the cavernous artery, which can generate an arterial-lacunar fistula. Anticoagulants (heparin and warfarin). Antihypertensives (i.e., hydralazine, guanethidine and propranolol). Hormones (i.e., gonadotropin releasing hormone and testosterone).

Diagnosis The diagnosis is often based on the history of the condition as well as a physical exam. Blood gas testing the blood from the cavernosa of the penis can help in the diagnosis. If the low-flow type of priapism is present, the blood typically has a low pH, while if the high-flow type is present, the pH is typically normal. Color Doppler ultrasound may also help differentiate the two. Testing a person to make sure they do not have a hemoglobinopathy may also be reasonable.

Ultrasonography

Penile ultrasonography with Doppler is the imaging method of choice, because it is noninvasive, widely available, and highly sensitive. By means of this method, it is possible to diagnose priapism and differentiate between its low- and high-flow forms. In low-flow (ischemic) priapism the flow in the cavernous arteries is reduced or absent. As the condition progresses, there is an increase in echogenicity of the corpora cavernosa, attributed to tissue edema. Eventually, changes in the echotexture of the corpora cavernosa can be observed due to the fibrotic transformation generated by tissue anoxia. In high-flow priapism normal or increased, turbulent blood flow in the cavernous arteries is seen. The area surrounding the fistula presents a hypoechoic, irregular lesion in the cavernous tissue.

Treatment Medical evaluation is recommended for erections that last for longer than four hours. Pain can often be reduced with a dorsal penile nerve block or penile ring block. For those with nonischemic priapism, cold packs and pressure to the area may be sufficient.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Priapism

Start with the simplest possible case. Write down what Priapism claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Priapism before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Priapism ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Priapism

In research: Priapism appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Priapism in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Priapism is common in secondary-school and first-year university syllabi. It links to neighbouring topics Medical emergencies, Men's health, Penis disorders, so understanding it makes those chapters shorter.
In everyday life: Look for Priapism outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Priapism in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Priapism means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Priapism out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Priapism in simple terms?

Why does Priapism matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Priapism?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Priapism.