## **Core Concept**
The patient's presentation of sudden respiratory distress, bilateral miosis (pupillary constriction), and bilateral basal crepts (crackles) over the chest, suggestive of pulmonary edema with a normal alveolar wedge pressure (PAWP), points towards a condition known as **non-cardiogenic pulmonary edema**. This condition occurs due to increased permeability of the pulmonary capillaries, leading to fluid leakage into the alveoli without elevated pressures in the left atrium.

## **Why the Correct Answer is Right**
The correct answer, **Heroin-induced pulmonary edema**, is a well-documented cause of non-cardiogenic pulmonary edema. Heroin use can lead to this condition through several mechanisms, including **direct toxic effects on the pulmonary capillary endothelium**, **hypoventilation leading to hypoxia**, and possibly an **immune-mediated response**. The presence of bilateral miosis is a key clinical clue pointing towards opioid use, as opioids cause pupillary constriction.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain infections can cause non-cardiogenic pulmonary edema, the specific combination of miosis and the acute presentation makes it less likely compared to a direct toxic cause like heroin.
- **Option B:** High-altitude pulmonary edema (HAPE) is a form of non-cardiogenic pulmonary edema but typically occurs in the context of recent high-altitude exposure, which is not mentioned in the scenario.
- **Option C:** Neurogenic pulmonary edema occurs after severe head injuries or other conditions affecting the brain. There's no direct indication of such a condition in the provided scenario.

## **Clinical Pearl / High-Yield Fact**
A critical point to remember is that **non-cardiogenic pulmonary edema** presents similarly to cardiogenic pulmonary edema but with a normal or low PAWP. Causes include **acute respiratory distress syndrome (ARDS)**, **severe infections**, **trauma**, and **drug use**, including heroin. The presence of miosis should prompt consideration of opioid-induced causes.

## **Correct Answer: D. Heroin-induced pulmonary edema**