Weakness and Dizziness Answers 387Patients can usually remember a preceding viral illness, usually gastroen-
teritis.Deep tendon reflexes are typically absent.
Hypokalemic periodic paralysis is part of the heterogeneous group of
muscle diseases known as periodic paralyses and is characterized by episodes
of flaccid muscle weakness occurring at irregular intervals. Most of the
conditions are hereditary and are more episodic than periodic. Peripheral
vascular disease (c), a common complication of longstanding diabetes, causes
paresthesias in the distal lower extremities and not acute paralysis. Tetanus
(d)manifests as muscular rigidity caused by the Clostridium tetanitoxin
preventing release of inhibitory neurotransmitters. Lockjaw is a common
complaint in generalized tetanus. A brain abscess (e)typically presents with
fever, headache, and focal neurologic findings and is usually caused by an
associated trauma, surgery, or infectious spread from another site.
349.The answer is c.(Rosen, pp 120-122.)Progressive paralysis in Guillain-
Barrésyndrome can rapidly ascend to the respiratory system and cause
respiratory failure.Patients need to be monitored and provided ventilator
support as necessary.
(a)Guillain-Barrésyndrome is a transient, not permanent, condition.
(b, d, and e)are not complications of the syndrome.
350.The answer is d.(Tintinalli et al, p 172.)This patient presents with
hypokalemia,secondary to increased potassium losses through vomiting
and diarrhea as well as reduced oral intake. Potassium deficiency results in
hyperpolarization of the cell membrane and leads to muscle weakness,
hyporeflexia, intestinal ileus, and respiratory paralysis.Characteristic
ECG findings include flattened T waves, U waves, and prolonged QT and PR
intervals.
Hyponatremia (a)and hypernatremia (b)mainly affect the central nervous
system (CNS), resulting in headache, anorexia, lethargy, and confusion. In
more severe cases, hyponatremia causes seizures, coma, and respiratory arrest;
whereas patients with profound hypernatremia develop ataxia, tremulousness,
and spasms. Hyperkalemia (c)can lead to cardiac dysrhythmias and typically
exhibits distinctive ECG findings including peaked T waves, prolonged QT
and PR intervals, and widened QRS complex that can progress to a sine
wave pattern. Signs of hypercalcemia (e)include bony and abdominal pain,
renal stones, and altered mental status (remembered by: “bones, stones, groans,
and psychiatric overtones”). In addition, cardiac effects include bradycardia,
heart blocks, and shortened QT interval on ECG.