Tony Montana, an international businessman, was rushed to the hospital due to vomiting and a decreased level of consciousness.

The patient displays slow and deep (Kussmaul breathing), and he is lethargic and irritable in response to stimulation.

He appears to be dehydrated—his eyes are sunken and mucous membranes are dry—and he has a two-week history of polydipsia, polyuria, and weight loss.

Measurement of arterial blood gas shows pH 7.0, PaC02 23 mm Hg, and HCO3 12 mmol/L; other results are Na+ 126 mmol/L, K+ 5 mmol/L, and C- 95 mmol/L. What is your assessment?

Choice A rationale

Placing an NG tube could potentially worsen a basilar skull fracture or cause further injury by penetrating the cranial vault if the cribriform plate is compromised. This intervention is contraindicated when clear fluid, possibly cerebrospinal fluid, is draining from the nose, indicating a potential breach in the dura mater.

Choice B rationale

Testing the clear fluid for the presence of glucose is a critical diagnostic step. Cerebrospinal fluid (CSF) contains glucose, whereas nasal secretions do not. A positive glucose test strongly indicates a CSF leak, which is a significant complication of facial trauma that requires specific management to prevent intracranial infection. Normal CSF glucose ranges from 40 to 70 mg/dL.

Choice C rationale

Encouraging coughing and deep breathing would increase intrathoracic and intracranial pressure, which could exacerbate a CSF leak and potentially introduce pathogens into the intracranial space. This action should be avoided as it poses a risk for further neurological complications such as meningitis.

Choice D rationale

Placing a mustache dressing on the patient might absorb the drainage but does not address the underlying issue of a potential CSF leak. Furthermore, applying pressure or occluding the nares could impede the free flow of CSF, potentially leading to a build-up of pressure and increasing the risk of retrograde infection into the central nervous system.

Choice A rationale

Diabetes insipidus is a condition characterized by the inability of the kidneys to conserve water, typically due to a deficiency in antidiuretic hormone (ADH) or kidney unresponsiveness to ADH. Post-neurosurgery, especially involving the pituitary or hypothalamus, ADH secretion can be impaired, leading to excessive urine output (polyuria), often exceeding 200 mL/hr, and dilute urine with a low specific gravity (normal range 1.005-1.030).

Choice B rationale

SIADH (Syndrome of Inappropriate Antidiuretic Hormone) is characterized by excessive ADH secretion, leading to water retention, hyponatremia, and concentrated urine. This condition would manifest as decreased urine output, not increased, and would be associated with a higher urine specific gravity (normal range 1.005-1.030) due to water reabsorption.

Choice C rationale

Acute Kidney Injury (AKI) involves a rapid decrease in kidney function, leading to the accumulation of waste products in the blood. While AKI can affect urine output, it typically results in oliguria (decreased urine output) or anuria (no urine output), rather than the profound polyuria observed in the patient.

Choice D rationale

Diabetes mellitus is a metabolic disorder characterized by high blood glucose levels due to insulin deficiency or resistance. While uncontrolled diabetes mellitus can cause polyuria due to osmotic diuresis from hyperglycemia, it would also present with other classic symptoms like polydipsia and polyphagia, and would be detected by elevated blood glucose levels (normal fasting plasma glucose <100 mg/dL).