Parkinson’s Disease: Complications

The following are the most important diseases or complications that may be contributed to by PD:

Eyes and eye appendages (H00-H59).

  • Keratoconjunctivitis sicca (KCS; dry eye syndrome; sicca syndrome; keratoconjunctivitis sicca; English “dry eye syndrome”) (applies to atypical Parkinson’s disease (PPS) with gaze paresis and early falls in the course of the disease and to idiopathic Parkinson’s disease (IPS)).

Skin and subcutaneous (L00-L99).

Cardiovascular system (I00-I99).

  • Orthostatic hypotension – lowered blood pressure that can cause dizziness and fainting when changing position.

Mouth, esophagus (food pipe), stomach, and intestines (K00-K67; K90-K93).

  • Gastroparesis (gastric paralysis).
  • Constipation (constipation) – due to degenerative processes of the enteric nervous system (ENS; “abdominal brain”):
    • The myenteric plexus (Auerbach’s plexus) between the annular and longitudinal muscle layers.
    • The submucosal plexus (Meissner’s plexus) in the submucosa (tissue layer between the mucosa and the muscle layer)

    This, in addition to intestinal motility (“ability of the intestine to move), regulates baseline gastrointestinal tone, secretion and absorption, which can lead to constipation refractory to therapy (“unresponsive to therapy”).

  • Hypersalivation (synonyms: sialorrhea, sialorrhea or ptyalism) – increased salivation.

Musculoskeletal system and connective tissue (M00-M99).

  • Arthralgia (joint pain)
  • Lumbar spine pain (patients with advanced PD); pain may be amenable to change in dopaminergic medication; recommendation: perform structured L-DOPA test with parallel monitoring of pain intensity; if change in dopamine dose does not improve → opioids (monitor efficacy every 3-6 months)

Neoplasms (C00-D48)

Psyche – Nervous System (F00-F99; G00-G99).

  • Akinetic crisis – inability to move.
  • Delirium – resulting from idiopathic Parkinson’s disease (IPS); delirium prevalence rates:
    • 4% of outpatients with IPS.
    • IPS patients treated as inpatients: 22-48 %.
    • IPS patients after surgical intervention: 11-60 %.

    Predisposing risk factors are: Age > 65 years, history of delirium, alcohol abuse, sensory impairment (visual or hearing impairment), depression cognitive impairment or dementia, multimorbidity.

  • Dementia/Parkinson’s dementia (PD-D) (incidence: 25% to 50%) – close association with:
    • Severe orthostatic hypotension: for every 10 mmHg that systolic pressure went down, the likelihood of dementia increased by 80%
    • Disturbance of color vision led to a threefold increase in the risk of dementia
    • Disturbed REM sleep; almost every patient was affected by it
    • Patients who already had mild cognitive impairment or other signs of cognitive decline such as psychotic symptoms or visual hallucinations
  • Depression (occurring in 35-45% of patients).
    • Two time points: early after diagnosis and, secondly, later in the course typically when impairment and disability increase.
    • In younger patients, depression often occurs before the onset of motor signs of disease and can therefore be considered an early symptom
  • Hypersomnia (increased daytime sleepiness).
  • Insomnia (sleep disturbances)
  • Mild cognitive impairment (LKB; mild cognitive impairment, MCI) in Parkinson’s disease (PD-MCI) – within the first five years after diagnosis, 57% of all people with PD develop mild cognitive impairment; after ten years, the majority of people with PD live with dementia
  • Psychosis
  • Restless Legs Syndrome (RLS) – Abnormal sensations mostly in the legs, rarely also in the arms, and associated urge to move. The complaints occur only at rest, so especially in the evening and at night.
  • Sleep-related breathing disorders (SBAS) – during sleep there are complete (apneas) and incomplete respiratory arrests (hypopneas) with consecutive repeated waking reactions (arousal).

Symptoms and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)

  • Chronic pain (>3 months) due to rigor (stiffness of muscles), akinesia (immobility, rigidity of movement), and postural disturbances: musculoskeletal pain, dystonic pain, radicular pain, and central neuropathic pain (frequency in descending order; 60-90% of patients); pain may occur as an early symptom before initial motor symptoms
  • Dysphagia (up to 75% of patients suffer from dysphagia at some point).

Genitourinary system (kidneys, urinary tract – reproductive organs) (N00-N99).

  • Bladder emptying disorders
  • Impotence

Prognostic factors

  • Cognitive deficits: metabolic syndrome is an independent risk factor for the development of cognitive deficits in PD patients.
  • Three factors determine Parkinson’s disease progression (progression of the disease):
    • Orthostatic hypotension (regulation disorder of blood pressure that occurs when changing to the upright posture).
    • REM sleep behavior disorder (English : rapid eye movement sleep behavior disorder, RBD).
    • Cognitive deficits (Mild cognitive impairment, MCI).

    The most marked progression observed in the diffuse malignant category (= 35% of patients) had patients with MCI, orthostatic hypotension of RBD (> 90% of cases). These patients also showed severe motor symptoms and complications. Also, increased depression and anxiety occurred.

  • Cognition:The GBA gene, which encodes the lysosomal protein β-glucocerebrosidase, increases the risk for Parkinson’s disease patients for cognitive decline when present in heterozygous form.Note: One in 30 people in the normal population is a heterozygous carrier of a mutant variant of GBA.