Pulse, absent or weak
Pulse, absent or weak: Excerpt from Handbook of Signs & Symptoms (Third Edition)
An absent or a weak pulse may be generalized or affect only one extremity. When generalized, this sign is an important indicator of such life-threatening conditions as shock and arrhythmia. Localized loss or weakness of a pulse that’s normally present and strong may indicate acute arterial occlusion, which could require emergency surgery. However, the pressure of palpation may temporarily diminish or obliterate superficial pulses, such as the posterior tibial or the dorsal pedal. Thus, bilateral weakness or absence of these pulses doesn’t necessarily indicate underlying pathology. (See Evaluating peripheral pulses.)
History and physical examination
If you detect an absent or a weak pulse, quickly palpate the remaining arterial
pulses to distinguish between localized or generalized loss or weakness. Then quickly check the patient’s other vital signs, evaluate his cardiopulmonary status, and obtain a brief history. Based on your findings, proceed with emergency interventions. (See Managing an absent or a weak pulse, pages 506 and 507.)
Medical causes
Aortic aneurysm (dissecting)
When a dissecting aneurysm affects circulation to the innominate, left common carotid, subclavian, or femoral artery, it causes weak or absent arterial pulses distal to the affected area. Absent or diminished pulses occur in 50% of patients with proximal dissection and usually involve the brachiocephalic vessels. Pulse deficits are much less common in patients with distal dissection and tend to involve the left subclavian and femoral arteries. Tearing pain usually develops suddenly in the chest and neck and may radiate to the upper and lower back and abdomen. Other findings include syncope, loss of consciousness, weakness or transient paralysis of the legs or arms, the diastolic murmur of aortic insufficiency, systemic hypotension, and mottled skin below the waist.
Aortic arch syndrome (Takayasu’s arteritis)
Aortic arch syndrome produces weak or abruptly absent carotid pulses and unequal or absent radial pulses. These signs are usually preceded by malaise, night sweats, pallor, nausea, anorexia, weight loss, arthralgia, and Raynaud’s phenomenon. Other findings include neck, shoulder, and chest pain; paresthesia; intermittent claudication; bruits; vision disturbances; dizziness; and syncope. If the carotid artery is involved, diplopia and transient blindness may occur.
Aortic bifurcation occlusion (acute)
Aortic bifurcation occlusion is a rare disorder that produces abrupt absence of all leg pulses. The patient reports moderate to severe pain in the legs and, less commonly, in the abdomen, lumbosacral area, or perineum. Also, his legs are cold, pale, numb, and flaccid.
Aortic stenosis
With aortic stenosis, the carotid pulse is sustained but weak. Dyspnea (especially on exertion or paroxysmal nocturnal), chest pain, and syncope dominate the clinical picture. The patient commonly has an atrial gallop. Other findings include a harsh systolic ejection murmur, crackles, palpitations, fatigue, and narrowed pulse pressure.
Arrhythmias
Cardiac arrhythmias may produce generalized weak pulses accompanied by cool, clammy skin. Other findings reflect the arrhythmia’s severity and may include hypotension, chest pain, dyspnea, dizziness, and a decreased level of consciousness (LOC).
Arterial occlusion
With acute occlusion, arterial pulses distal to the obstruction are unilaterally weak and then absent. The affected limb is cool, pale, and cyanotic, with an increased capillary refill time, and the patient complains of moderate to severe pain and paresthesia. A line of color and temperature demarcation develops at the level of obstruction. Varying degrees of limb paralysis may also occur, along with intense intermittent claudication. With chronic occlusion, occurring with disorders such as arteriosclerosis and Buerger’s disease, pulses in the affected limb weaken gradually.
Cardiac tamponade
Life-threatening cardiac tamponade causes a weak, rapid pulse accompanied by these classic findings: paradoxical pulse, jugular vein distention, hypotension, and muffled heart sounds. Narrowed pulse pressure, pericardial friction rub, and hepatomegaly may also occur. The patient may appear anxious, restless, and cyanotic and may have chest pain, clammy skin, dyspnea, and tachypnea.
Coarctation of the aorta
Findings of coarctation of the aorta include bounding pulses in the arms and neck, with decreased pulsations and systolic pulse pressure in the lower extremities.
Peripheral vascular disease
Peripheral vascular disease causes a weakening and loss of peripheral pulses. The patient complains of aching pain distal to the occlusion that worsens with exercise and abates with rest. The skin feels cool and shows decreased hair growth. Impotence may occur in male patients with occlusion in the descending aorta or femoral areas.
Pulmonary embolism
Pulmonary embolism causes a generalized weak, rapid pulse. It may also cause an abrupt onset of chest pain, tachycardia, dyspnea, apprehension, syncope, diaphoresis, and cyanosis. Acute respiratory findings include tachypnea, dyspnea, decreased breath sounds, crackles, a pleural friction rub, and a cough — possibly with blood-tinged sputum.
Shock
With anaphylactic shock, pulses become rapid and weak and then uniformly absent within seconds or minutes after exposure to an allergen. This is preceded by hypotension, anxiety, restlessness, feelings of doom, intense itching, a pounding headache and, possibly, urticaria.
With cardiogenic shock, peripheral pulses are absent and central pulses are weak, depending on the degree of vascular collapse. Pulse pressure is narrow. A drop in systolic blood pressure to 30 mm Hg below baseline, or a sustained reading below 80 mm Hg, produces poor tissue perfusion. Resulting signs include cold, pale, clammy skin; tachycardia; rapid, shallow respirations; oliguria; restlessness; confusion; and obtundation.
With hypovolemic shock, all pulses in the extremities become weak and then uniformly absent, depending on the severity of hypovolemia. As shock progresses, remaining pulses become thready and more rapid. Early signs of cardiogenic shock include restlessness, thirst, tachypnea, and cool, pale skin. Late signs include hypotension with narrowing pulse pressure, clammy skin, a drop in urine output to less than
25 ml/hour, confusion, a decreased LOC and, possibly, hypothermia.
With septic shock, all pulses in the extremities first become weak. Depending on the degree of vascular collapse, pulses may then become uniformly absent. Shock is heralded by chills, a sudden fever and, possibly, nausea, vomiting, and diarrhea. Typically, the patient experiences tachycardia, tachypnea, and flushed, warm, and dry skin. As shock progresses, he develops thirst, hypotension, anxiety, restlessness, and confusion. Then pulse pressure narrows and the skin becomes cold, clammy, and cyanotic. The patient experiences severe hypotension, oliguria or anuria, respiratory failure, and coma.
Thoracic outlet syndrome
A patient with thoracic outlet syndrome may develop gradual or abrupt weakness or loss of the pulses in the arms, depending on how quickly vessels in the neck compress. These pulse changes commonly occur after the patient works with his hands above his shoulders, lifts a weight, or abducts his arm. Paresthesia and pain occur along the ulnar distribution of the arm and disappear as soon as the patient returns his arm to a neutral position. The patient may also have asymmetrical blood pressure and cool, pale skin.
Other causes
Treatments
Localized absent pulse may occur distal to arteriovenous shunts for dialysis.
Special considerations
Continue to monitor the patient’s vital signs to detect untoward changes in his condition. Monitor hemodynamic status by measuring daily weight and hourly or daily intake and output and by assessing central venous pressure.
Pediatric pointers
Radial, dorsal pedal, and posterior tibial pulses aren’t easily palpable in infants and small children, so be careful not to mistake these normally hard-to-find pulses for weak or absent pulses. Instead, palpate the brachial, popliteal, or femoral pulses to evaluate arterial circulation to the extremities. In children and young adults, weak or absent femoral and more distal pulses may indicate coarctation of the aorta.
Pictures
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: Cardiac Arrest (Sudden Cardiopulmonary Collapse) (A Pocket Manual of Differential Diagnosis)
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