23

23 CASE 23


A 38-year-old man presents to his primary care physician complaining of difficulty in voiding for the past 6 months.


The patient was diagnosed with insulin-dependent diabetes mellitus at age 15. He has managed his diabetes with daily injections of insulin and has been able to achieve good plasma glucose control.



PHYSICAL EXAMINATION



VS: T 37°C, P 72/min, R 15/min, BP 120/80 mm Hg

PE: Unremarkable


LABORATORY STUDIES



Cystoscopy: No obstruction

Cystometry: Weak contraction of the detrusor muscle

Plasma analysis:
• Fasting glucose: 90 mg/dL (normal: 75-115 mg/dL)

• BUN: 12 mg/dL (normal: 7-18 mg/dL)

• Creatinine: 1.0 mg/dL (normal: 0.6-1.2 mg/dL)

• Plasma albumin: 3.8 mg/dL (normal: 3.5-5.5 mg/dL)

• Glycosylated hemoglobin: A1c (HbA1c) levels 4.2% (normal: 3.8% to 6.4%)

Urinalysis:
• Glucose: 0 (normal: 0)

• Albuminuria: 0 mg/24 hr (normal: 0)

• Urine cultures: Negative


DIAGNOSIS


Neurogenic bladder



PATHOPHYSIOLOGY OF KEY SYMPTOMS


Urine produced in the kidneys is transported through the ureter by peristalsis and is stored in the bladder until elimination from the body. The detrusor muscle is the major structural component of the bladder wall. The wall of the bladder is highly compliant and can accommodate an increase in volume of 300 mL with only a small increase in pressure.


When there is little urine in the bladder no pressure is exerted against the bladder wall. An increase in 50 to 300 mL of urine exerts a pressure against the wall, generating a force of 5 to 10 cm H2O. Increases in volume above 300 mL cause pressure to rise; and above 400 mL, intrabladder pressure rises rapidly. Bladder cystometry measures the tension developed within the bladder (Fig. 23-1).


image

FIGURE 23–1 Normal cystometrogram also showing acute pressure waves (dashed spikes) caused by micturition reflexes.

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Jul 4, 2016 | Posted by in PHYSIOLOGY | Comments Off on 23

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