An adolescent weighing 42 kg has a urine output of 520 mL over 8 hours.

What is the patient's actual urine output in milliliters per kilogram per hour (mL/kg/hr)? Round your answer to the nearest tenth and enter only digits (not units). —

Choice A rationale

Risk for infection is a generalized diagnosis and is not specific to the hemodynamic consequences of a large patent ductus arteriosus (PDA). The primary pathophysiology involves a left-to-right shunting of oxygenated blood leading to pulmonary overcirculation and systemic underperfusion, which are more critical issues.

Choice B rationale

A large PDA allows a significant volume of blood to shunt from the aorta (higher pressure) to the pulmonary artery (lower pressure). This diversion of systemic blood volume results in decreased systemic cardiac output and perfusion, leading to compensatory tachycardia and eventual heart failure.

Choice C rationale

Fluid volume deficit is incorrect. The left-to-right shunting in a large PDA causes increased pulmonary blood flow and pressure, leading to pulmonary congestion, which can manifest as fluid volume excess in the lungs and sometimes systemically, not a deficit.

Choice D rationale

The excessive blood flow shunting to the lungs due to a large PDA causes pulmonary overcirculation and pressure increase. This over-perfusion impairs alveolar-capillary gas exchange dynamics, leading to pulmonary edema and ventilation-perfusion mismatch, increasing the risk for impaired gas exchange.

Choice E rationale

The chronic strain on the heart from the increased volume and pressure load due to the large left-to-right shunt requires increased myocardial work. This leads to cardiac muscle fatigue and an inability to meet the body's metabolic demands during exertion, resulting in activity intolerance and poor weight gain.

Choice A rationale

Photophobia, or an extreme sensitivity to light, is a common symptom in meningitis, resulting from the meningeal irritation and inflammation caused by the bacterial infection. The meninges, the protective layers covering the brain and spinal cord, contain pain-sensitive fibers. When inflammation reaches the optic nerve pathways or specific cranial nerves, light perception becomes a painful stimulus.

Choice B rationale

A petechial or purpuric rash is a critical and potentially ominous finding, especially in meningococcemia (caused by Neisseria meningitidis). The rash is caused by endothelial damage and vasculitis as the bacteria and inflammatory mediators enter the bloodstream, leading to small, non-blanching hemorrhages beneath the skin due to capillary leakage and microthrombi formation.

Choice C rationale

Nuchal rigidity (stiffness of the neck), a classic sign, is caused by inflammation of the meninges surrounding the cervical spinal cord. Attempting to flex the neck stretches the irritated meninges, eliciting pain and muscle spasm. This rigidity is often assessed using maneuvers like Brudzinski's or Kernig's signs, indicating meningeal irritation.

Choice D rationale

A high-pitched cry is more commonly associated with increased intracranial pressure (ICP), which can be a complication of severe meningitis, particularly in infants due to hydrocephalus or cerebral edema. While a sign of neurological distress, it is a less direct or specific initial symptom compared to the direct signs of meningeal irritation or systemic infection.

Choice E rationale

Seizures are a frequent complication, particularly in infants and young children with bacterial meningitis. They result from the direct inflammatory irritation of the cerebral cortex by the infectious process, cerebral edema, or vascular changes (e.g., thrombosis, infarcts) associated with severe intracranial infection, causing abnormal electrical activity.